WO2021241367A1

WO2021241367A1 - Friction-charging nonwoven fabric and method for manufacturing same

Info

Publication number: WO2021241367A1
Application number: PCT/JP2021/019046
Authority: WO
Inventors: 拓磨白武; 悠一郎高島
Original assignee: 日本バイリーン株式会社
Priority date: 2020-05-27
Filing date: 2021-05-19
Publication date: 2021-12-02

Abstract

The problem to be solved by the present invention is providing a friction-charging nonwoven fabric in which two or more types of fibers having differing constituent resins are mixed, the nonwoven fabric being thin and having superior strength.　The present invention is a friction-charging nonwoven fabric in which two or more types of fibers having differing constituent resins are mixed, the thickness of the nonwoven fabric being 1.2 mm or less, and the maximum point strength being greater than 43.0 N/50 mm. Moreover, the present invention is a method for manufacturing a friction-charging nonwoven fabric in which two or more types of fibers having differing constituent resins are mixed, said method having: (1) a step for preparing a web in which two or more types of fibers having different constituent resins are mixed; (2) a step for performing a hydroentangling process on the web and formulating a hydroentangled web; and (3) a step for deforming the hydroentangled web in the thickness direction and applying, to the hydroentangled web that was deformed in the thickness direction, tensile force in a direction perpendicular to the thickness direction, whereby constituent fibers of the hydroentangled web are twisted together.

Description

Triboelectric non-woven fabric and its manufacturing method

The present invention relates to a triboelectric nonwoven fabric and a method for producing the same.

Conventionally, air filters and masks have been required to have low pressure loss, excellent air permeability, and excellent collection efficiency of atmospheric dust, dust such as PM2.5, and pollen. In order to satisfy both of these contradictory performances, air filters and masks provided with triboelectric non-woven fabrics have been studied.
As such a triboelectric non-woven fabric, Japanese Patent Application Laid-Open No. 2006-218342 (Patent Document 1) provides a needle punching process on a web in which two or more types of fibers having different constituent resins (hereinafter, may be referred to as triboelectric fibers) are mixed. Disclosed is a triboelectric non-woven fabric that is charged by rubbing the triboelectric fibers against each other. Specifically, in the examples of Patent Document 1, it is disclosed that a triboelectric non-woven fabric can be prepared by rubbing friction-charged fibers with each other by performing a needle punching process on a web subjected to a water flow entanglement treatment.

JP 2006-218342

The applicant of the present application tried to provide a thin triboelectric non-woven fabric so as to meet the needs of air filters and masks having various thicknesses and shapes.

However, it has been difficult to provide a thin triboelectric non-woven fabric as long as the conventional technique of rubbing the triboelectric fibers with each other by needle punching to charge the fibers is used. The reason for this is that, as is clear from the description in the examples of the present application described later, when a needle punching process is performed on a web in which triboelectric fibers are mixed in order to rub the triboelectric fibers against each other, the thickness of the web is doubled. To do. Therefore, in order to provide a thin triboelectric non-woven fabric (for example, a triboelectric non-woven fabric having a thickness of 1.2 mm or less), it is necessary to lighten the basis weight of the web in which the triboelectric fibers are mixed.

However, although the triboelectric non-woven fabric prepared by performing needle punching on a web with a light weight mixed with triboelectric fibers is thin, the needle punching forms holes derived from needle processing such as through holes in the web. Probably because of this, the strength was greatly reduced. Such a friction-charged non-woven fabric having a weak strength (for example, a friction-charged non-woven fabric having a maximum point strength of 43.0 N / 50 mm or less) is processed so as to have a three-dimensional shape such as pleats by punching with tension applied. When processing into an air filter or mask, breaks or cracks may occur, which may cause deterioration of the filtration performance of the prepared air filter or mask.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a triboelectric nonwoven fabric in which two or more types of fibers having different constituent resins are mixed, which is thin and has excellent strength. Is to be.

As a result of diligent studies, the present inventors have succeeded in realizing a triboelectric non-woven fabric that is thin and has excellent strength. Specifically, we have succeeded in realizing a triboelectric non-woven fabric having the physical characteristics of "thickness is 1.2 mm or less and maximum point strength is higher than 43.0 N / 50 mm".
Further, the present inventors have described in a method for producing a triboelectric non-woven fabric, in which a water flow entangled web prepared by subjecting a web containing triboelectric fibers to a water flow entanglement treatment is subjected to a step of rubbing and charging the triboelectric fibers. The water flow entangled web was deformed in the thickness direction, and tension was applied to the water flow entangled web after being deformed in the thickness direction in a direction perpendicular to the thickness direction. It has been found that a triboelectric non-woven fabric that is thin and has excellent strength can be realized for the first time by efficiently rubbing the constituent fibers of the water flow entangled web with each other without using the needle punching process by the manufacturing method having this step. .. Specifically, by the method for producing a triboelectric nonwoven fabric according to the present invention, a triboelectric nonwoven fabric having the physical characteristics of "thickness is 1.2 mm or less and maximum point strength is higher than 43.0 N / 50 mm" is realized. succeeded in.

That is, the first invention is a triboelectric nonwoven fabric in which two or more types of fibers having different constituent resins are mixed, and the thickness is 1.2 mm or less, and the maximum point strength is higher than 43.0 N / 50 mm. , Triboelectric non-woven fabric.

The second invention is a method for producing a triboelectric nonwoven fabric in which two or more types of fibers having different constituent resins are mixed.
(1) A process of preparing a web in which two or more types of fibers having different constituent resins are mixed.
(2) A step of preparing a water flow entangled web by subjecting the web to a water flow entanglement treatment.
(3) By deforming the water flow entangled web in the thickness direction and applying tension to the water flow entangled web after being deformed in the thickness direction in a direction perpendicular to the thickness direction. The step of rubbing the constituent fibers of the water flow entangled web with each other,
It is a method of manufacturing a triboelectric non-woven fabric having the above.

According to the present invention, it is possible to obtain a triboelectric nonwoven fabric that is thin and has excellent strength.

In the present invention, various configurations such as the following configurations can be appropriately selected. Unless otherwise specified or specified, the various measurements described in the present invention were carried out under normal pressure under 25 ° C. temperature conditions. Then, unless otherwise specified or specified, the various measurement results described in the present invention were obtained by measurement up to a value one digit smaller than the desired value, and the value to be obtained was calculated by rounding off the value. As a specific example, if the value up to the first decimal place is the value to be obtained, the value up to the first decimal place is calculated by finding the value up to the second decimal place by measurement and rounding off the obtained value to the second decimal place. Then, this value was used as the value to be calculated. Further, each upper limit value and each lower limit value exemplified in the present invention can be arbitrarily combined.

The triboelectric nonwoven fabric according to the present invention is a charged nonwoven fabric composed of two or more types of charged fibers having different constituent resins. The term "two or more types of fibers having different constituent resins" as used herein means that two or more types of fibers are mixed in the triboelectric non-woven fabric, and in the two or more types of fibers, the surface (both ends) of the first type of fiber is used. It means that the constituent resin of (excluding the portion) and the constituent resin of the surface of other fibers (excluding both ends) are different. Hereinafter, the fiber constituting the triboelectric nonwoven fabric according to the present invention may be referred to as a triboelectric fiber.

Further, "a mixture of two or more types of fibers having different constituent resins" here means that the above-mentioned two or more types of triboelectric fibers are intertwined with each other. For example, in a web prepared by uniformly mixing two or more types of triboelectric fibers and supplying them to a card machine, two or more types of fibers having different constituent resins are mixed, and the present invention can be made by using the web. Such a triboelectric non-woven fabric can be prepared.

The triboelectric non-woven fabric is breathable and the constituent fibers are randomly present, so that it provides an air filter and mask with high void ratio, uniform pore diameter, low pressure loss, and excellent breathability and collection efficiency. can.

The type of triboelectric fibers may be appropriately selected as long as it is a combination of fibers that are charged by rubbing against each other. As a combination of the first kind of friction charged fiber and the second kind of friction charged fiber, for example, a combination of a polyolefin fiber and an acrylic fiber; a fluorine fiber and a polyamide fiber, wool, a glass fiber, silk or rayon. Combination with fiber; Urethane fiber and polyamide fiber, wool, glass fiber, silk or rayon fiber; Vinyl chloride fiber and polyamide fiber, wool, glass fiber, silk or rayon fiber Combination of polyolefin fiber and polyamide fiber, wool, glass fiber, silk or rayon fiber; combination of acrylic fiber and polyamide fiber, wool, glass fiber, silk or rayon fiber; vinylon type Combination of fiber with polyamide fiber, wool, glass fiber, silk or rayon fiber; combination of polyester fiber with polyamide fiber, wool, glass fiber, silk or rayon fiber; acetate fiber and polyamide fiber Combinations with fibers, wool, glass fibers, silk or rayon fibers; combinations of polyolefin fibers and polyester fibers and the like can be mentioned.
Among these, if the combination of the polyolefin fiber and the acrylic fiber is used, the amount of charge can be increased by rubbing the triboelectric fibers against each other, and it is possible to provide an air filter or mask having excellent collection efficiency. It is preferable because a triboelectric non-woven fabric can be realized.

Examples of the constituent resin of the polyolefin-based fiber include polypropylene resin, polyethylene resin, polystyrene resin, vinyl acetate copolymer resin, ethylene-propylene copolymer, or a part of these resins using a nitrile group, a cyano group, or a halogen. Examples thereof include a substituted resin, and the polyolefin-based fiber can be a composite fiber composed of one kind or two or more kinds of these constituent resins. For example, it may be a core-sheath type composite fiber, and the sheath component may be a polyolefin-based fiber made of a polyolefin-based resin.

Further, it is preferable that the constituent resin of the polyolefin fiber contains a phosphorus-based additive or a sulfur-based additive. By containing a phosphorus-based additive or a sulfur-based additive, the amount of charge can be increased and the initial collection efficiency can be improved. In addition to the phosphorus-based additive and the sulfur-based additive, other additives such as phenol-based and amine-based additives may be further contained. If the total amount of these additives is large, the spinnability may be deteriorated. Therefore, the total amount of the additives is preferably 5% by mass or less of the polyolefin fiber, and preferably 2% by mass or less. It is more preferably 1% by mass or less, and further preferably 1% by mass or less.

Examples of the phosphorus-based additive include trisnonylphenyl phosphite, tris (2,4-di-t-butylphenyl) phosphite, distearylpentaerythritol diphosphite, and bis (2,4-di-t-butyl). Phenyl) pentaerythritol phosphite, bis (2,6,di-t-butyl-4-methylphenyl) pentaerythritol phosphite, 2,2-methylenebis (4,6-di-t-butylphenyl) octylphosphite, Tetrax (2,4-di-t-butylphenyl) -4,4'-biphenylene-di-phosphonite, bis (2,4-bis (1,1-dimethylethyl) -6-methylphenyl) ethyl ester subphosphorus Acid, tetrakis (2,4-di-t-butylphenyl) (1,1-biphenyl) -4,4'-diylbisphosphonite, bis (bis (2,4-di-t-butyl-5-) Phenyl antioxidants such as methylphenoxy) phosphino) can be mentioned. This phosphorus-based additive is preferably contained in an amount of 0.01% by mass or more, more preferably 0.2% by mass or more, and more preferably 0.3% by mass or more in the polyolefin-based fiber. Is more preferable, and it is more preferable that the content is 0.6% by mass or more. Sulfur-based additives include sulfur such as dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, disstearyl-3,3'-thiodipropionate, and pentaerythritol tetrakis. A system antioxidant or the like can be preferably used. The sulfur-based additive is preferably contained in the polyolefin fiber in an amount of 0.01% by mass or more, more preferably 0.1% by mass or more.

As the acrylic fiber, either a polyacrylonitrile fiber containing acrylonitrile as a main component (85% or more) or a modacrylic fiber containing acrylonitrile 35% or more and less than 85% can be used. Further, there are two types of polyacrylonitrile-based fibers, one spun using an organic solvent and one spun using an inorganic solvent, and any polyacrylonitrile-based fiber may be used.

The friction-charged fiber is, for example, a melt spinning method, a dry spinning method, a wet spinning method, a direct spinning method (melt blow method, spunbond method, electrostatic spinning method, etc.), and removal of one or more resin components from a composite fiber. It can be obtained by a known method such as a method of extracting a fiber having a small fiber diameter and a method of beating the fiber to obtain a divided fiber.

The fineness of the triboelectric fiber is not particularly limited as long as the object of the present invention can be achieved. The fineness of the triboelectric fiber is preferably 0.1 to 10 dtex, preferably 0.3 to 7 dtex, so that the triboelectric non-woven fabric can provide an air filter or mask having low pressure loss and excellent air permeability and collection efficiency. It is preferably 0.6 to 5 dtex, and most preferably 0.8 to 3 dtex. The "fineness" is obtained by the method A specified in JIS L1015: 2010, 8.5.1 (positive amount fineness).
It should be noted that the fineness of various triboelectric fibers can be increased because the triboelectric fibers can be efficiently rubbed against each other for two or more types of triboelectric fibers that are intertwined with each other and exist in the triboelectric non-woven fabric. Is preferably close. Specifically, the percentage of the fineness of the other type of triboelectric fiber to the fineness of one type of triboelectric fiber is preferably 250% or less, more preferably 220% or less, 130. It is more preferably% or less. Ideally, the fineness of the various triboelectric fibers is most preferably the same (ie, the percentage is 100%).
When the triboelectric non-woven fabric contains three or more types of triboelectric fibers, the fineness is confirmed for the two types of triboelectric fibers having a large mass ratio as described above.

The fiber length of the triboelectric fiber is not particularly limited as long as the object of the present invention can be achieved, and may be a short fiber, a long fiber or a continuous fiber. However, by realizing a triboelectric non-woven fabric in which triboelectric fibers are randomly present, it is possible to provide an air filter or mask having a high void ratio, a uniform pore diameter, low pressure loss, and excellent air permeability and collection efficiency. The fiber length is preferably 3 to 150 mm, more preferably 10 to 100 mm, and even more preferably 30 to 80 mm, because it is a triboelectric non-woven fabric.
The "fiber length" is obtained by JIS L1015: 2010, 8.4.1 [corrected staple diagram method (B method)].

For the plurality of types of triboelectric fibers contained in the triboelectric non-woven fabric, the mixing ratio of each triboelectric fiber is appropriately adjusted. For example, when the triboelectric non-woven fabric contains two types of triboelectric fibers (triboelectric fiber A and triboelectric fiber B), the mixing ratio of the triboelectric fiber A and the triboelectric fiber B is 5% by mass: 95% by mass. It can be up to 95% by mass: 5% by mass, 15% by mass: 85% by mass to 85% by mass: 15% by mass, 25% by mass: 75% by mass to 75% by mass: 25% by mass. Can be.

The triboelectric non-woven fabric may contain fibers other than the triboelectric fibers. The percentage of the mass of triboelectric fibers in the mass of the fibers that make up the triboelectric non-woven fabric can be adjusted as appropriate, but triboelectric charging can provide air filters and masks with low pressure loss and excellent air permeability and collection efficiency. Like a triboelectric, it is preferably 50% by mass or more, more preferably 65% by mass or more, further preferably 80% by mass or more, and the fibers constituting the triboelectric non-woven fabric are triboelectric fibers. Most preferably only.

The fibers constituting the triboelectric non-woven fabric may contain an oil agent. The type of oil agent can be appropriately selected, and a hydrophilic oil agent or a non-hydrophilic oil agent can be adopted. The hydrophilic oil agent referred to here refers to a treatment agent that enhances the hydrophilicity of the fiber surface, and known components and formulations can be used. For example, a lubricant such as mineral oil or synthetic oil containing a wetting agent such as an anionic surfactant or a nonionic surfactant may be mentioned. Further, the non-hydrophilic oil agent refers to a treatment agent that reduces the hydrophilicity of the fiber surface, and known components and formulations can be used. For example, those in which the type and amount of the surfactant are adjusted, and those in which a lubricant such as mineral oil or synthetic oil contains a fluorine-based or silicone-based component can be mentioned.

The type of the oil agent can be confirmed by subjecting the oil agent extracted from the fibers constituting the triboelectric nonwoven fabric as described later to a known analyzer such as FT-IR (ATR method).
The triboelectric non-woven fabric can be used as a constituent fiber because it can prevent an increase in the water content of the triboelectric non-woven fabric and increase the amount of charge due to rubbing between the triboelectric fibers to realize a triboelectric-charged non-woven fabric having excellent collection efficiency. It is preferable to contain triboelectric fibers to which a non-hydrophilic oil agent is applied.

The percentage of the oil agent contained in the constituent fibers of the friction-charged non-woven fabric can be adjusted as appropriate, but the percentage of the oil agent mass in the fiber mass is preferably 0.01% by mass or more, preferably 0.05% by mass or more. It is more preferably 0.08% by mass or more, further preferably 0.10% by mass or more, and particularly preferably 0.11% by mass or more. The upper limit can be adjusted as appropriate, but it is realistic that it is 1% by mass or less. The percentage (unit: mass%) of the oil agent mass contained in the fibers constituting the triboelectric nonwoven fabric was first subjected to the sampled test piece to the methanol extraction method described in the JIS L-1015 chemical staple test method. The mass of the oil contained in the test piece is obtained from the measured mass. Then, determine the conversion value in terms of the mass of oil contained in the test piece of 1 m ² around (g / m ^2), further, the converted value to total fiber mass constituting the test piece (g / m ²⁾ The percentage of oil is calculated, and the calculated value is taken as the percentage of the oil mass (unit: mass%).

The fibers constituting the triboelectric non-woven fabric may be in a state where the fibers are integrated with each other by a binder or fiber adhesion. However, in the charging method according to the present invention, the triboelectric fibers can efficiently rub against each other to provide a triboelectric non-woven fabric having a large amount of charge, and the constituent fibers of the triboelectric non-woven fabric can be connected to each other while the gas passes through the triboelectric non-woven fabric. Since the triboelectric fibers are maintained in charge by efficiently rubbing against each other, it is possible to provide a triboelectric non-woven fabric that can provide an air filter or mask having excellent collection efficiency. Therefore, it is preferable that the fibers constituting the triboelectric non-woven fabric are triboelectric non-woven fabrics in which the fibers are not integrated with each other by a binder or fiber adhesion, and the fibers are simply entangled with each other. Further, it is preferable to use a triboelectric nonwoven fabric in which fibers are simply entangled with each other, because it is possible to provide a triboelectric nonwoven fabric in which contamination is less likely to occur and the texture is less likely to deteriorate.

The friction-charged nonwoven fabric has a fiber layer in which fibers are oriented in one direction (for example, a direction parallel to the transport direction) (fiber layer A, for example, a fiber layer derived from a one-way web) and a direction different from the above-mentioned one direction. It is preferable to have a structure in which a fiber layer in which the fibers are oriented (fiber layer B, for example, a fiber layer derived from crosslay web) is laminated. As a specific example, a fiber layer made by laminating one-way webs containing triboelectric fibers so as to have different fiber orientations, and one-way webs and crosslay webs containing triboelectric fibers are laminated. It is preferable that the fiber layer is made of the Chris Crossweb. Due to the triboelectric non-woven fabric having such a layer structure, the fiber layer B is applied to the non-woven fabric or the web in the transport direction in the step of rubbing the constituent fibers of the web according to the present invention. The fiber orientation of the fabric moves so as to be parallel to the transport direction. As a result, the triboelectric fibers in the fiber layer B are strongly rubbed against each other, and the triboelectric fibers existing between the layers are rubbed more strongly due to the rubbing between the fiber layer A and the fiber layer B. It is preferable because a triboelectric non-woven fabric can be realized.
Alternatively, since the triboelectric fibers in the fiber layer rub against each other strongly, a non-woven fabric having a fiber layer in which the fibers are oriented in various directions (for example, a fiber layer derived from a random web) is preferable.
The orientation of the fibers in the fiber layer of the triboelectric non-woven fabric can be confirmed visually or by a micrograph of the surface or cross section of the fiber layer. Further, when the manufacturing process of the triboelectric nonwoven fabric is known, the orientation of the fibers in the fiber layer can be determined from the type of web used in the manufacturing process.

^{The texture of the triboelectric nonwoven fabric is not particularly limited, but it is preferably 15 to 200 g / m 2} and 25 to 150 g / m ² so that a triboelectric nonwoven fabric having excellent rigidity such as the maximum point strength described later can be prepared. It is more preferably present, and even more preferably 30 to 100 g / m ² . The "Metsuke" is ^{the mass per 1 m 2} , and is obtained by the method specified in JIS L1085: 1998, 6.2 "Mass per unit area".

The thickness of the triboelectric nonwoven fabric according to the present invention is 1.2 mm or less, which can meet the needs of air filters and masks having various thicknesses and shapes. If the thickness of the triboelectric non-woven fabric is 1.2 mm or less, the value can be adjusted as appropriate according to the needs, but it can be widely met by the needs of air filters and masks having various thicknesses and shapes (for example, thick air filters). However, if it is a thin charged nonwoven fabric, it can meet the needs by laminating a plurality of thin charged nonwoven fabrics), and it is 1.1 mm or less. It is preferably 1.0 mm or less, more preferably 0.9 mm or less, and particularly preferably 0.8 mm or less. The lower limit value can be adjusted as appropriate, but it is realistic that it is 0.1 mm or more.
The "thickness" in the present invention is a random measurement of the thickness in a load region performed by loading 0.98 N (= 100 gf) in the thickness direction per ^{5 cm 2} area on the main surface of the base material. It is carried out at 5 selected places, and means the value obtained by arithmetically averaging those thicknesses. Such a thickness measurement can be performed by, for example, a high-precision digital length measuring machine (Mitutoyo Co., Ltd., Lightmatic (registered trademark)).

The lower the apparent density of the triboelectric nonwoven fabric according to the present invention, the lower the pressure loss and the better the air permeability of the air filter or mask. Therefore, the apparent density of the frictional charging nonwoven can be 0.15 g / cm ³ or less, preferably less than 0.15 g / cm ^3, more preferably 0.14 g / cm ³ or less , further preferably 0.13 g / cm ³ or less, particularly preferably 0.12 g / cm ³ or less.
The lower limit can be adjusted as appropriate, but since it is possible to realize an air filter or mask that is less likely to reduce pressure loss due to its high strength, it is ^{higher than 0 g / cm 3} and 0.04 g / cm ³ or more. Is preferable. The apparent density (g / cm ³ ) of the triboelectric nonwoven fabric can be calculated by dividing the triboelectric nonwoven fabric's texture (g / m ² ) by the thickness (mm).

The triboelectric nonwoven fabric according to the present invention is characterized in that it is highly rigid even though its thickness is 1.2 mm or less, and its maximum point strength is higher than 43.0 N / 50 mm. Since the triboelectric nonwoven fabric according to the present invention has a maximum point strength higher than 43.0 N / 50 mm, it can be used for air filters and masks, for example, by punching it in a state where tension is applied or by processing it into a three-dimensional shape such as pleats. It is prevented from breaking or cracking during processing, and it is difficult to deteriorate the filtration performance of the prepared air filter or mask. If the maximum point strength of the triboelectric nonwoven fabric is higher than 43.0 N / 50 mm, the value can be appropriately adjusted according to the needs. It is preferably 50 N / 50 mm or more, more preferably 60 N / 50 mm or more, further preferably 70 N / 50 mm or more, further preferably 80 N / 50 mm or more, and 90 N / 50 mm or more. Is particularly preferable. The upper limit value can be adjusted as appropriate, but it is realistic that it is 300 N / 50 mm or less. The maximum point strength referred to in the present invention is a value obtained by subjecting the object to be measured to the following measuring method.

(Measurement method of maximum point strength)
Make sure that the machine direction (transportation direction at the time of manufacture) and the long side direction match from the object to be measured, and the length can be measured by the test piece (shape: rectangle, long side: constant speed extension type tensile tester described later). It was longer than 100 mm, and the short side: 50 mm) was collected. Then, the collected test piece is subjected to a constant-speed extension type tensile tester (Orientec, Tensilon, initial grip interval: 100 mm, tensile speed: 300 mm / min), and the long side of the test piece is obtained until the test piece breaks. I pulled it in the direction. The maximum value of the measured intensities measured before the test piece broke was defined as the maximum point intensity (unit: N / 50 mm) of the object to be measured.

For objects to be measured whose length in the long side direction is smaller than 100 mm, the initial grip interval is adjusted to be longer than the fiber length of the short fiber with the longest fiber length excluding the long fiber. A test piece collected from the object to be measured is provided to a rapid extension type tensile tester, and the maximum point strength (unit: N / 50 mm) of the object to be measured is obtained by the same measurement. When the constituent fibers are composed of only long fibers, the initial gripping interval of 10 mm or more can be secured, and the maximum point strength (unit: N / 50 mm) of the object to be measured can be obtained by the same measurement.

If the mechanical direction of the object to be measured is unknown, the length of the test piece (shape: rectangle, long side: length that can be measured by the above-mentioned constant speed extension type tensile tester) from various directions of the object to be measured. Collect multiple pieces (short side: 50 mm) longer than 100 mm. Then, each of the collected test pieces is subjected to the above-mentioned measurement method. Then, among the maximum values of the measured intensities in each measured test piece, the highest value is regarded as the maximum point intensity (unit: N / 50 mm) of the object to be measured.

For a measurement object whose length in the short side direction is smaller than 50 mm, a test piece (shape: rectangular, long side: length that can be measured by the above-mentioned constant speed extension type tensile tester) collected from the measurement object. (Longer than 100 mm, short side: smaller than 50 mm) is applied to a constant-speed elongation type tensile tester in the same manner as described above, and the maximum per length of the short side in the object to be measured is measured in the same manner. Find the point strength. Then, by converting the obtained maximum point strength per length of the short side of the object to be measured into the maximum point strength per 50 mm of the length of the short side of the object to be measured, the maximum point strength of the object to be measured ( Unit: N / 50 mm) can be calculated. Specifically, a test piece having a short side length of 10 mm was subjected to a constant-speed extension type tensile tester, and the maximum point strength per 10 mm short side length in the measurement object obtained by measurement was 1N. If so, it can be calculated that the maximum point strength of the object to be measured is 5N / 50 mm by conversion.

Triboelectric non-woven fabric (test piece) can be collected from an air filter or mask in order to obtain each of the above-mentioned values. At that time, a section is collected from a portion other than the welded portion of the air filter or mask which has a flat plate shape by opening the pleated fold. Then, by removing unnecessary components such as a cover material from the section, a test piece used for obtaining each value can be collected.

In the triboelectric nonwoven fabric according to the present invention, the points where the triboelectric fibers rub against each other are positively or negatively charged. That is, positively charged portions and negatively charged portions are randomly distributed and exist on the surface of the triboelectric fiber. On the other hand, in the charged nonwoven fabric obtained for the corona charging treatment, positively charged portions are unevenly distributed on the surface of one main surface side of the charged nonwoven fabric in the constituent fibers, and the positively charged portions are unevenly distributed on the other main surface side of the charged nonwoven fabric. Negatively charged parts are unevenly distributed on the surface. Therefore, the triboelectric nonwoven fabric according to the present invention and the charged nonwoven fabric provided for the corona charging treatment have different charged states in the constituent fibers.

Since the triboelectric non-woven fabric according to the present invention has the triboelectric fibers in the charged state described above, dust, pollen and the like tend to be uniformly collected on the surface of the triboelectric fibers. As a result, it is possible to realize an air filter or mask having excellent collection efficiency.

Next, a method for manufacturing a triboelectric nonwoven fabric capable of producing the triboelectric nonwoven fabric according to the present invention will be described. The configuration described above will be omitted.

This manufacturing method includes (1) a step of preparing a web in which two or more types of fibers having different constituent resins are mixed.

The two or more types of fibers having different constituent resins are a plurality of types of triboelectric fibers constituting the triboelectric nonwoven fabric according to the present invention, or a plurality of types of triboelectric fibers and fibers other than the triboelectric fibers. The method of preparing the web in which these fibers are mixed can be appropriately selected, but the method of preparing the web by blending each fiber at the desired blending ratio and supplying it to the card device, and the method of preparing the web by supplying each fiber of the desired blending ratio to the air array device and depositing them. A method of preparing a web, or a method of preparing a web in which each fiber is mixed at a required compounding ratio by using direct spinning such as a melt blow nonwoven fabric, a spunbonded nonwoven fabric, or an electrostatically spun nonwoven fabric can be adopted.

Various values such as the basis weight and thickness of the web are appropriately adjusted so that the triboelectric nonwoven fabric according to the present invention can be prepared. Although the web may contain a binder or an adhesive fiber, the web may contain a triboelectric non-woven fabric having a large amount of charge by efficiently rubbing the triboelectric fibers with each other in the charging method according to the present invention. It is preferable that it does not contain binders or adhesive fibers, and it is preferable that the web is composed of only constituent fibers (more preferably only triboelectric fibers).

Further, it is preferable that the fiber is provided with a hydrophilic oil agent or a non-hydrophilic oil agent. Since the web contains an oil agent, it is possible to prevent the occurrence of fiber breakage in the step of rubbing the constituent fibers of the step (3) described later. As a result, it is possible to provide a triboelectric non-woven fabric that can prevent a decrease in the amount of charge and provide an air filter or mask having excellent collection efficiency. In particular, it is preferable to use triboelectric fibers to which a non-hydrophilic oil agent is applied, because it is possible to prevent an increase in water content and increase the amount of charge due to rubbing between the triboelectric fibers.

This manufacturing method has (2) a step of applying a water flow entanglement treatment to the web to prepare a water flow entanglement web.

In the water flow entanglement process applied to the web, adjust the strength of the water flow and the spacing and arrangement of the nozzles that radiate the water flow as appropriate. The type of water used for the water flow entanglement treatment can be appropriately selected, and may be, for example, industrial water, clean water, distilled water, pure water, or the like. In addition, water after being used for the water flow entanglement treatment (which may contain an oil agent or the like that has fallen off from the fiber) may be repeated and used for the water flow entanglement treatment.

The average water pressure per nozzle, excluding the pre-shower, is preferably 2 MPa or more, preferably 3 MPa or more, so that the fibers can be entangled with each other and have excellent rigidity and a thin triboelectric non-woven fabric can be prepared. It is more preferably 4 MPa or more, and further preferably 4 MPa or more. On the other hand, if the average water pressure is too high, the entanglement between the constituent fibers becomes too strong, and the porosity becomes unintentionally low, which may make it difficult to provide an air filter or mask having a low pressure loss. Therefore, it is preferably 25 MPa or less, more preferably 20 MPa or less, further preferably 18 MPa or less, and most preferably 16 MPa or less.
In this step, only one main surface of the web may be subjected to the water flow entanglement treatment, or both main surfaces of the web may be subjected to the water flow entanglement treatment. Further, the number of times of the water flow entanglement treatment may be once or a plurality of times.

The water flow entanglement web thus prepared may be subjected to the next step in a wet state by the water flow entanglement treatment, but the dry water flow is so that triboelectric charging is performed more efficiently. It is preferable to use the entangled web for the next step. A method of drying the water flow entangled web moistened by the water flow entanglement treatment can be appropriately selected, but a method of providing the web to a heating device, a method of drying by exposing to atmospheric pressure or reduced pressure, and the like can be adopted. The type of heating device can be selected as appropriate, and for example, a method using a device that heats or pressurizes with a roller, an oven dryer, a far-infrared heater, a dry heat dryer, a hot air dryer, a device that can irradiate and heat infrared rays, etc. is adopted. can. The heating temperature by the heating device is appropriately selected, but it is appropriately adjusted so that the water content can be evaporated and the constituent components such as constituent fibers are not unintentionally decomposed or denatured. If an adhesive component such as a binder or an adhesive fiber or a crosslinkable resin is present on the web, the binder may be bonded or the fiber may be bonded by subjecting the web to a heat treatment, or the crosslinkable resin may be crosslinked. ..

In this manufacturing method, (3) the water flow entangled web is deformed in the thickness direction, and tension is applied to the water flow entangled web after being deformed in the thickness direction in a direction perpendicular to the thickness direction. It has a step of rubbing the constituent fibers of the water flow entangled web.

In the method for producing a triboelectric nonwoven fabric according to the present invention, by deforming the water flow entangled web in the thickness direction, the triboelectric fibers contained in the water flow entangled web can be rubbed against each other to charge the water flow entangled web. .. The method of deforming the water flow entangled web in the thickness direction can be appropriately selected, but a method of applying a roller to the water flow entangled web, a method of providing the water flow entangled web with a clearance that can be deformed in the thickness direction, and the like can be adopted.

As a specific example
A mode in which a water flow entanglement web is provided between two rollers adjusted to have a clearance thinner than the thickness of the water flow entanglement web.
-The member between the two rollers adjusted to have a thinner clearance than the thickness of the water flow entangled web and the thickness of the member (for example, a transport conveyor) that conveys the water flow entangled web. A mode to provide a water flow entanglement web,
-A mode in which the water flow entanglement web is provided to the clearance formed by a member such as a plate, a rod, a conveyor, and a roller, which is adjusted to have a clearance thinner than the thickness of the water flow entanglement web.
-For plates, rods, conveyors, etc. adjusted to have a thinner clearance than the thickness of the water flow entangled web and the thickness of the member (for example, a conveyor) that conveys the water flow entangled web. A mode in which a water flow entanglement web is provided to the clearance formed by a member and a single roller, etc.
And so on.

The length of the clearance may be any as long as the water flow entangled web can be deformed in the thickness direction, and the length can be adjusted as appropriate, but it is preferably less than 100% of the thickness of the water flow entangled web, and is preferably 80% or less. It is preferably 60% or less, and preferably 40% or less. In this step, when the water flow entangled web is deformed in the thickness direction by using an easily deformable member having an elastic member on the surface such as a rubber roller or a polyurethane conveyor, the clearance may be 0.

The material of the pressure member (hereinafter referred to as the pressure member) used to deform the water flow entangled web such as rollers and conveyors in the thickness direction, and various physical properties such as the hardness of the surface thereof are efficient. Select as appropriate so that a triboelectric non-woven fabric can be produced well.

Also, as another specific example,
-The contact is made by bringing the water entangled web into contact with the surface of the roller and changing the transport direction of the water entangled web before contacting the roller and the transport direction of the water entangled web after contacting the roller. Examples thereof include a mode in which a force acts in the thickness direction of the water flow entangled web in the portion where the water flow is entangled.
In this step, pressure is applied to the main surface of the water flow entangled web in contact with the surface of the roller on the opposite side to the roller side by using another roller or a conveyor so that the triboelectric nonwoven fabric can be efficiently manufactured. May act. Further, a speed difference may be provided between the speed at which the roller conveys the water flow entangled web and the speed at which the other roller or the transfer conveyor conveys the water flow entangled web.

The presence or absence of rotation, the rotation speed, and the rotation direction of the roller can be selected as appropriate. For example, when a water flow entangled web is provided between two rollers, the presence / absence of rotation, the rotation speed, and the rotation direction between the two rollers may be different combinations. Further, the speed at which the conveyor conveys the water flow entangled web can be appropriately adjusted.

The pressure acting in the thickness direction of the water flow entangled web and the magnitude of the tension acting on the water flow entangled web during transportation are appropriately adjusted so that the desired triboelectric non-woven fabric can be produced. Adjust appropriately so that the entangled web does not crack, break, or change unintended physical properties.

In the method for manufacturing a triboelectric nonwoven fabric according to the present invention, tension is applied to the water flow entangled web after being deformed in the thickness direction in a direction perpendicular to the thickness direction of the water flow entangled web. By this step, the triboelectric fibers contained in the water flow entangled web can be further rubbed against each other to further charge the water flow entangled web. In the present invention, "tension is applied in a direction perpendicular to the thickness direction" means that the water flow entanglement web acts on the water flow entanglement web before it comes into contact with the pressurizing member. Rather than the tension acting in the direction perpendicular to the thickness direction of the web, the thickness direction of the water entanglement web acting on the water entanglement web after the water entanglement web comes into contact with the pressurizing member. It means that the tension acting in the vertical direction is larger.

A method of applying tension to the water flow entangled web after contact with the pressurizing member in a direction perpendicular to the thickness direction can be appropriately selected. for example,
・ Water flow entanglement after contact with the pressurizing member by another roller or conveyor that rotates at a speed that can be conveyed at a higher speed than the transfer speed of the web at the time of contact with the pressurizing member. How to transport or wind the web,
・ Punch the water entangled web after it comes into contact with the pressurizing member while applying tension to the water entangled web in the direction perpendicular to the thickness direction of the water entangled web. Method,
Etc. can be adopted.

The transport direction of the water flow entangled web until the pressurizing member is applied and the transport direction of the water flow entangled web after the pressurizing member is acted on may be the same direction or different directions. However, when the directions are different from each other, tension can be applied more effectively in the thickness direction of the water flow entangled web and the direction perpendicular to the thickness direction, and a triboelectric non-woven fabric having a large amount of charge can be produced, which is preferable.

The magnitude of the tension applied to the water flow entangled web after contacting the pressure member is appropriately adjusted so that the desired triboelectric nonwoven fabric can be produced, but the water flow entangled web is cracked, broken or has unintended physical properties. Adjust appropriately so that no change occurs.

According to the manufacturing method of the present invention, the frictionally charged fibers, which are constituent fibers, are not only in the thickness direction (one dimension in the Z-axis direction) but also in the thickness direction and the transport direction (Z-axis direction and the X-axis direction). Friction-charged fibers efficiently interact with each other in a three-dimensional direction (Z-axis direction, X-axis direction, and Y-axis direction) other than the transport direction (Z-axis direction, X-axis direction, and Y-axis direction) that are perpendicular to the thickness direction, the transfer direction, and the thickness direction. Rubbing and friction charging are performed. Therefore, it is possible to realize a triboelectric non-woven fabric having a large amount of charge and excellent filter performance even though the thickness is as thin as 1.2 mm or less.

As a result of the study by the present inventors, an attempt was made to reduce the thickness of the triboelectric non-woven fabric prepared by performing the needle punching process by subjecting it to the calendar process, although the thickness can be temporarily reduced. In the calendar processing, the entangled state of the fibers did not change, so the thickness returned to the original with time.

The triboelectric non-woven fabric produced in this way can be used as a filter material by itself, but a cover material, a support, and / or a pre-filter, a backup filter, etc. are laminated on the triboelectric non-woven fabric to form a filter material. You may. As the cover material, the support, and / or the pre-filter and the backup filter, known ones can be adopted, and for example, a cloth, a porous film, a breathable foam, or the like can be adopted. Even if the laminated filter material is made by simply laminating the illustrated material and the triboelectric non-woven fabric, it can be bonded by using a binder, hot melt web, or fiber bonding to perform bonding treatment such as heat sealing or ultrasonic welding. It may be a laminated filter material made of.

Further, the outer shape of the filter material provided with the triboelectric nonwoven fabric and the triboelectric nonwoven fabric can be appropriately adjusted and is not particularly limited, but for example, a two-dimensional sheet shape, a three-dimensional corrugated shape, a pleated shape, or a cylinder. It can be a shape or the like. The filter material provided with the triboelectric nonwoven fabric and the triboelectric nonwoven fabric may have a cutout portion, a punched portion, or a notch portion.

Examples of the present invention will be described below, but the present invention is not limited to the following examples. The evaluation method in the following examples is as follows.

(Reference example)
A unidirectional web and a crosslay web were prepared by uniformly mixing 70% by mass of polypropylene fibers having the configurations shown in Table 1 and 30% by mass of acrylic fibers and feeding them to a card machine. Then, a Chris Crossley web was prepared by laminating a one-way web and a crosslay web.
A water flow entanglement treatment (water pressure: 3 MPa, process transfer speed: 5 m / min) was performed from one main surface side (A) to the other main surface side (B) of the Chris Rossley web. Then, under the same conditions, the water flow entanglement treatment (water pressure: 3 MPa, process transfer speed: 5 m / min) is performed again from the other main surface side (B) of the Chris Crosslay web to the one main surface side (A). provided. Then, the water contained in the Chris Crosley web was removed by subjecting the Chris Crosley web subjected to the water flow entanglement treatment to an oven dryer (heating temperature: 80 ° C.).
In this way, a water flow entangled web was prepared. The prepared water flow entangled web was a web formed by laminating a fiber layer A in which fibers are oriented in one direction and a fiber layer B in which fibers are oriented in a direction different from the above one direction. ..

(Comparative Example 1)
The water flow entangled web prepared in the reference example was subjected to needle punching from one main surface side (A) to the other main surface side (B) ^{under the condition of a needle density of 50 lines / cm 2.} Triboelectrically charged.
In this way, a triboelectric non-woven fabric was prepared.

(Comparative Example 2)
A water flow entangled web was prepared in the same manner as in the reference example, except that the basis weight of the Chris Crosley web used was increased. A triboelectric nonwoven fabric was prepared in the same manner as in Comparative Example 1 except that the water flow entangled web prepared in this manner was used.

(Example 1)
With the water flow entangled web prepared in the reference example placed on a transport conveyor whose surface is made of polyurethane material and is easily deformed, the fiber orientation of the fiber layer A constituting the water flow entangled web and the transport direction are parallel to each other. Then, it was conveyed at a transfer speed of 25.0 m / min. Then, the water flow is brought into contact with the metal roller (roller rotation direction: rotation direction in which the water flow entanglement web can be conveyed downstream in the transfer direction) whose clearance with the transfer conveyor is adjusted to 0 mm. The entangled web was deformed in the thickness direction and triboelectrically charged. At this time, a speed difference (conveying speed of the water flow entangled web by the transport conveyor: 25.0 m / min, moving speed on the surface of the metal roller: 24.5 m / min) is generated between the conveyor in contact with the water flow entangled web and the metal roller. By providing it, the friction between the triboelectric fibers is further promoted.
Next, the water flow entangled web after contacting the metal roller was conveyed toward the downstream side in the transport direction of the water flow entangled web at a transport speed of 25.5 m / min. In this way, by applying tension to the water flow entangled web in a direction perpendicular to the thickness direction, the constituent fibers of the water flow entangled web were rubbed against each other and further triboelectrically charged.
In this way, a triboelectric non-woven fabric was prepared.

(Example 2)
A water flow entangled web was prepared in the same manner as in the reference example, except that the basis weight of the web used was increased. A triboelectric nonwoven fabric was prepared in the same manner as in Example 1 except that the water flow entangled web prepared in this manner was used.

Table 1 shows various physical properties of the water flow entangled web of the reference example and each triboelectric nonwoven fabric manufactured as described above. In the following tables, the fibers to which the alkylphosphate ester, which is a non-hydrophilic oil agent, is given are marked with the NH mark, and the fibers to which the hydrophilic oil agent is given are marked with the H mark. In addition, the percentage of the oil agent mass contained in the fibers constituting the water flow entangled web or the triboelectric non-woven fabric is described in the "percentage of the oil agent (mass%)" column.
The ventilation resistance (unit: Pa) and the collection efficiency (unit:%) were determined by using the water flow entangled web of the reference example and each triboelectric non-woven fabric for the following measurement methods. Further, a QF value capable of evaluating the filter performance was calculated from the obtained values of the aeration resistance (unit: Pa) and the collection efficiency (unit:%).

(Measurement method of ventilation resistance and collection efficiency)
Specimens were collected from each of the water flow entangled webs and each triboelectric non-woven fabric of the reference example. Then, the collected test piece was attached to a measuring device "AP-9000" manufactured by Sibata Scientific Technology Co., Ltd., and the collection efficiency and the ventilation resistance were measured. At the time of measurement, the test piece was attached so that the main surface side derived from one main surface side (A) of the web in the test piece faces the upstream side of the measuring device.
First, the test flow rate is adjusted so that the effective filtration area of ^{the test piece is 40 liters per minute per 124 cm 2} (for example, the test flow rate supplied to the test piece ^{having an effective filtration area of 12.4 cm 2 is 4 liters per minute).} The differential pressure between the upstream and the downstream in the piece was measured, and the ventilation resistance (unit: Pa) of the test piece was obtained from the measured differential pressure.

Next, the test flow rate is adjusted so that the effective filtration area of ^{the test piece is 30 liters per minute at 124 cm 2} (for example, the test flow rate supplied to the test piece ^{having an effective filtration area of 12.4 cm 2 is 3 liters per minute).} Test containing sodium chloride particles (median particle size distribution: 0.06 to 0.10 μm, geometric standard deviation: 1.8 or less) at a concentration of 50 mg / m ³ or less (concentration variation: ± 15% or less) The airflow was supplied to the upstream side of the test piece. Then, after the test air flow was supplied for 1 minute, the concentrations of the sodium chloride particles present on the upstream side and the downstream side of the test piece were measured using a light scattering type dust densitometer, and the test was performed from both of the measured concentrations. The concentration of sodium chloride particles collected in the pieces was calculated. Then, the percentage of the concentration of the sodium chloride particles collected in the test piece to the concentration of the sodium chloride particles supplied to the upstream side of the test piece is calculated, and the value is used as the collection efficiency of the test piece (unit::). %).

It should be noted that the lower the ventilation resistance, the easier it is to breathe if it is a mask filter, and if it is an air filter, it means that the energy and equipment load can be reduced, and the filter performance is rich. Therefore, the aeration resistance is preferably 50 Pa or less, preferably 40 Pa or less, preferably 30 Pa or less, preferably 20 Pa or less, preferably 10 Pa or less, and most preferably 5 Pa or less. The lower limit can be adjusted as appropriate, but 0.5 Pa or more is realistic.

In addition, the higher the collection efficiency, the better the filtration performance of atmospheric dust and pollen. Therefore, the collection efficiency is preferably 50% or more, preferably 60% or more, preferably 70% or more, preferably 80% or more, preferably 90% or more, and most preferably 95 or more.

(Calculation method of QF value)
The QF value (without unit) was calculated by substituting the values of the aeration resistance (unit: Pa) and the collection efficiency (unit:%) calculated as described above into the following equation. It should be noted that the higher the QF value, the better the balance between the low ventilation resistance value and the high collection efficiency, and the better the filter performance.
QF value = -Ln (1-A / 100) / B
Ln: Natural logarithm A: Collection efficiency (unit:%)
B: Ventilation resistance (unit: Pa)

From the result of comparing the thickness of the water flow entangled web of the reference example and the triboelectric non-woven fabric prepared in Comparative Example 1, a needle punching process was performed on the web in which the triboelectric fibers were mixed in order to rub the triboelectric fibers against each other. It turns out that the thickness of the web doubles. Furthermore, from the results of comparing the maximum point strengths of the water flow entangled web of Reference Example and the triboelectric nonwoven fabric prepared in Comparative Example 1, it was found that the strength was significantly reduced when the needle punching treatment was performed.
It should be noted that such a friction-charged nonwoven fabric having a weak strength (for example, a friction-charged nonwoven fabric having a maximum point strength of 43.0 N / 50 mm or less) has a three-dimensional shape such as pleats, which is punched in a state where tension is applied. When processing into an air filter or mask such as processing, breakage or cracks may occur, which may cause deterioration of the filtration performance of the prepared air filter or mask.

Then, from the result of comparing the triboelectric nonwoven fabrics prepared in Comparative Example 1 and Comparative Example 2, in order to prepare a thin triboelectric nonwoven fabric (for example, a triboelectric nonwoven fabric having a thickness of 1.2 mm or less), it is frictionally charged. It turned out that it was necessary to lighten the texture of the web mixed with fibers. However, from the results of comparing the maximum point strengths of the triboelectric nonwoven fabrics prepared in Comparative Example 1 and Comparative Example 2, the triboelectric nonwoven fabric prepared by performing needle punching on a web having a light texture mixed with triboelectric fibers is , It turned out that the strength is greatly reduced.

From the above, in a triboelectric nonwoven fabric in which two or more types of fibers having different constituent resins are mixed, as long as the prior art is used, it is thin (specifically, the thickness is 1.2 mm or less) and has excellent strength (specifically). It was not possible to prepare a triboelectric non-woven fabric (with a maximum point strength higher than 43.0 N / 50 mm).

In contrast to the above findings, the triboelectric nonwoven fabrics prepared in Examples 1 and 2 are triboelectric nonwoven fabrics having physical properties such that the thickness is 1.2 mm or less and the maximum point strength is higher than 43.0 N / 50 mm. rice field. The reason for this is that in the method for producing a triboelectric nonwoven fabric according to the present invention, the constituent fibers of the water flow entangled web can be rubbed against each other to be triboelectricly charged without performing needle punching on the web, so that the web is thin and has excellent strength. It was possible to realize a triboelectric non-woven fabric.

(Example 3)
A water flow entangled web was prepared in the same manner as in the reference example except that the acrylic fiber having the composition shown in Table 2 was adopted. A triboelectric nonwoven fabric was prepared in the same manner as in Example 1 except that the water flow entangled web thus prepared was used.

(Example 4)
A water flow entangled web was prepared in the same manner as in the reference example except that polypropylene fibers having the configurations shown in Table 2 were adopted. A triboelectric nonwoven fabric was prepared in the same manner as in Example 1 except that the water flow entangled web thus prepared was used.
Table 2 shows various physical properties of each triboelectric nonwoven fabric manufactured as described above. In Table 2, the results of Example 1 are also shown for easy understanding.

The triboelectric nonwoven fabrics prepared in Examples 3 to 4 were all triboelectric nonwoven fabrics having a thickness of 1.2 mm or less and a maximum point strength of more than 43.0 N / 50 mm. From this, according to the present invention, even when various triboelectric fibers having different fineness and fiber length are adopted, "the thickness is 1.2 mm or less and the maximum point strength is more than 43.0 N / 50 mm". It was possible to realize a triboelectric non-woven fabric having the physical characteristics of "high".

(Example 5)
A water flow entangled web was prepared in the same manner as in the reference example, except that polypropylene fibers and acrylic fibers having the configurations shown in Table 3 were adopted.
Then, the water flow entangled web is placed in a calendar roll whose surface is made of a metal material so that the fiber orientation of the fiber layer A constituting the water flow entangled web is parallel to the transport direction (rotation direction: transport direction of the water flow entangled web). The water flow entangled web was pressurized under the conditions of a rotation direction capable of transporting to the downstream side and a linear pressure of 100 kg / cm), deformed in the thickness direction, and frictionally charged. Immediately after passing through the calendar roll, tension (1.7 N / 50 mm) was applied to the water flow entangled web in the transport direction to further promote friction between the triboelectric fibers.
In this way, by applying tension to the water flow entangled web in a direction perpendicular to the thickness direction, the constituent fibers of the water flow entangled web were rubbed against each other and further triboelectrically charged. In this way, a triboelectric non-woven fabric was prepared.

(Example 6)
A triboelectric nonwoven fabric was prepared in the same manner as in Example 5 except that the water flow entangled web was pressurized under the condition of a linear pressure of 60 kg / cm.

(Example 7)
A unidirectional web was prepared by uniformly mixing 70% by mass of polypropylene fibers having the configurations shown in Table 3 and 30% by mass of acrylic fibers and feeding them to a card machine.
A water flow entanglement treatment (water pressure: 3 MPa, process transfer speed: 5 m / min) was performed from one main surface side (A) of the one-way web to the other main surface side (B). Then, under the same conditions, water flow entanglement treatment (water pressure: 3 MPa, process transfer speed: 5 m / min) is performed again from the other main surface side (B) of the one-way web to the one main surface side (A). bottom. Then, the water contained in the one-way web was removed by subjecting the one-way web subjected to the water flow entanglement treatment to an oven dryer (heating temperature: 80 ° C.).
In this way, a water flow entangled web was prepared. The prepared water flow entangled web was a web composed of only the fiber layer A in which the fibers were oriented in one direction.
A triboelectric nonwoven fabric was prepared in the same manner as in Example 5, except that the water flow entangled web thus prepared was used.

(Example 8)
A water flow entangled web was prepared in the same manner as in the reference example except that polypropylene fibers and acrylic fibers having the configurations shown in Table 3 were adopted. A triboelectric nonwoven fabric was prepared in the same manner as in Example 5, except that the water flow entangled web thus prepared was used.
Table 3 shows various physical properties of each triboelectric nonwoven fabric manufactured as described above.

The triboelectric nonwoven fabrics prepared in Examples 5 to 8 were all triboelectric nonwoven fabrics having a thickness of 1.2 mm or less and a maximum point strength of more than 43.0 N / 50 mm.

Further, from the results of comparing Examples 5 to 8, the following was found.
-From the results of comparing Example 5 and Example 6, a triboelectric non-woven fabric having a low ventilation resistance is provided because ^{the apparent density is less than 0.15 g / cm 3} (more preferably 0.12 g / cm ^{3 or less).} It turned out that it could be done.
From the result of comparing Example 5 and Example 7, the fiber layer A in which the fibers are oriented in one direction and the fiber layer B in which the fibers are oriented in a direction different from the one direction are laminated. It has been found that by having the structure, it is possible to provide a triboelectric non-woven fabric having high collection efficiency.
From the results of comparing Examples 5 and 8, it was found that the triboelectric fibers constituting the triboelectric nonwoven fabric contain a non-hydrophilic oil agent, so that the triboelectric nonwoven fabric with high collection efficiency can be provided. bottom.
In each triboelectric nonwoven fabric other than Example 7 prepared as described above, the fiber layer A in which the fibers are oriented in one direction and the fiber layer B in which the fibers are oriented in a direction different from the above one direction are used. It had a structure in which and were laminated. Further, since it is manufactured without performing needle punching, the triboelectric nonwoven fabric prepared in each example does not have holes derived from needle processing such as through holes by needle punching.

From the above, it is possible to meet the needs of air filters and masks having various thicknesses and shapes depending on the triboelectric nonwoven fabric and the manufacturing method thereof according to the present invention.

By using the frictionally charged non-woven fabric according to the present invention, for example, it is used in a production factory for foods and medical products, a manufacturing factory for precision equipment, an indoor cultivation facility for agricultural products, a general household use or an industrial facility such as an office building, and air. It is possible to prepare air filters for electric appliances such as purifiers and OA equipment, and for various vehicles such as automobiles and aircraft. Further, a mask can be prepared by using the triboelectric nonwoven fabric according to the present invention.
Further, the above-mentioned triboelectric nonwoven fabric can be produced by the method for producing a triboelectric nonwoven fabric according to the present invention.

Claims

A triboelectric non-woven fabric in which two or more types of fibers with different constituent resins are mixed.
The thickness is 1.2 mm or less, and the maximum point strength is higher than 43.0 N / 50 mm.
Triboelectric non-woven fabric.
This is a method for manufacturing a triboelectric non-woven fabric in which two or more types of fibers having different constituent resins are mixed.
(1) A process of preparing a web in which two or more types of fibers having different constituent resins are mixed.
(2) A step of preparing a water flow entangled web by subjecting the web to a water flow entanglement treatment.
(3) By deforming the water flow entangled web in the thickness direction and applying tension to the water flow entangled web after being deformed in the thickness direction in a direction perpendicular to the thickness direction. The step of rubbing the constituent fibers of the water flow entangled web with each other,
A method for manufacturing a triboelectric nonwoven fabric.