JP6955645B1 - Triboelectric non-woven fabric and its manufacturing method - Google Patents

Abstract

An object to be solved by the present invention is to provide a triboelectric non-woven fabric in which two or more kinds of fibers having different constituent resins are mixed, which is thin and has excellent strength. The triboelectric non-woven fabric of the present invention is a triboelectric non-woven fabric in which two or more types of fibers having different constituent resins are mixed, and has a thickness of 1.2 mm or less and a maximum point strength of 43.0 N / 50 mm or more. Further, the method for producing a friction-charged nonwoven fabric of the present invention is a method for producing a friction-charged nonwoven fabric in which two or more types of fibers having different constituent resins are mixed, and (1) two or more types of fibers having different constituent resins are mixed. A step of preparing a web, (2) a step of applying a water flow entanglement treatment to the web to prepare a water flow entangled web, (3) deforming the water flow entangled web in the thickness direction and the thickness direction. The present invention includes a step of rubbing the constituent fibers of the water flow entangled web by applying a tension to the water flow entangled web after being transformed into a water flow entangled web in a direction perpendicular to the thickness direction.

Description

The present invention relates to a triboelectric non-woven 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 triboelectric fibers can be rubbed against each other to prepare a triboelectric non-woven fabric 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 has attempted 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 charging by rubbing the triboelectric fibers with each other by needle punching 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 reduce 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 having 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 in a state where tension is 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 non-woven 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 the water flow entangled web was 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 non-woven fabric according to the present invention, a triboelectric non-woven fabric having a physical property 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 non-woven fabric in which two or more kinds 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. , A triboelectric non-woven fabric.

The second invention is a method for producing 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
It is a method for producing a frictionally charged non-woven fabric having the above.

According to the present invention, it is possible to obtain a triboelectric non-woven fabric which 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 are measured to a value one digit smaller than the desired value, and the obtained value is calculated by rounding off the value. As a specific example, when 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 up to the second decimal place. Then, this value was used as the desired value. Further, each upper limit value and each lower limit value exemplified in the present invention can be arbitrarily combined.

The triboelectric non-woven fabric according to the present invention is a charged non-woven fabric composed of a mixture 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 the surface (both ends) of the first type of fibers in the two or more types of fibers. It means that the constituent resin of the surface of the other fiber (excluding both ends) is different from the constituent resin of the other fiber (excluding the portion). Hereinafter, the fiber constituting the triboelectric non-woven 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" as used herein means that the above-mentioned two or more types of triboelectric fibers are entwined 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 to provide an air filter or 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 type of friction charged fiber and the second type 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 fiber Combination of fiber and polyamide fiber, wool, glass fiber, silk or rayon fiber; combination of polyester fiber and 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, when 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. Substituted resins and the like can be mentioned, 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, the constituent resin of the polyolefin fiber preferably contains a phosphorus-based additive and 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. More preferably, it is 1% by mass or less.

Examples of phosphorus-based additives 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 a polyolefin-based fiber 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. 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 a polyolefin-based fiber in an amount of 0.01% by mass or more, and 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) and 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, spun bond 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 fibers having a small fiber diameter and a method of beating the fibers to obtain divided fibers.

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 fibers 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 to form 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 proportion of existing mass 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. ~ 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 non-woven fabric, 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 a mineral oil or a synthetic oil containing a wetting agent such as an anionic surfactant or a nonionic surfactant can 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 non-woven fabric as described later to a known analyzer such as FT-IR (ATR method).
It should be noted that the triboelectric non-woven fabric can be used as a constituent fiber because it is possible to 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 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. To determine the percentage (unit: mass%) of the mass of the oil agent contained in the fibers constituting the triboelectric non-woven fabric, first, the collected test piece was subjected to the methanol extraction method described in the JIS L-1015 chemical staple test method. Obtain the mass of the oil contained in the test piece 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⁾ Is calculated, and the calculated value is taken as the percentage (unit: mass%) of the oil agent mass.

The fibers constituting the triboelectric non-woven fabric may be in a state in which 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 be efficiently rubbed 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 provided 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, a triboelectric non-woven fabric in which fibers are simply entangled with each other is preferable because it is possible to provide a triboelectric non-woven fabric in which contamination is unlikely to occur and the texture is not easily deteriorated.

The friction-charged non-woven 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 formed by laminating unidirectional webs containing triboelectric fibers so as to have different fiber orientations, and unidirectional webs and crosslay webs containing triboelectric fibers are laminated. It is preferable that the fiber layer is made of the Chris Crossweb. By being a triboelectric non-woven fabric having such a layer structure, in the step of rubbing the constituent fibers of the web according to the present invention, when a tension is applied to the non-woven fabric or the web in the transport direction, the fiber layer B 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 by rubbing the fiber layer A and the fiber layer B, resulting in a large amount of charge and excellent collection efficiency. 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 non-woven 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 non-woven 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 non-woven fabric having excellent rigidity such as the maximum point strength described later can be prepared. It is more preferably present, and further 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 non-woven fabric according to the present invention is 1.2 mm or less, and it is possible to 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 non-woven fabric, it can meet the needs by laminating a plurality of thin charged non-woven fabrics), and it is 1.1 mm or less. It is more preferably 1.0 mm or less, further 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 in which 0.98 N (= 100 gf) is loaded in the thickness direction per ^{5 cm 2 of} an area with respect to the main surface of the base material. It is carried out at 5 selected locations, and means the value obtained by arithmetically averaging the thicknesses. Such thickness measurement can be performed by, for example, a high-precision digital length measuring machine (manufactured by Mitutoyo Co., Ltd., Lightmatic (registered trademark)).

The lower the apparent density of the triboelectric non-woven fabric according to the present invention, the lower the pressure loss and the more excellent 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 non-woven fabric can be calculated by dividing the triboelectric non-woven fabric's texture (g / m ² ) by the thickness (mm).

The triboelectric non-woven fabric according to the present invention is characterized in that it is highly rigid despite having a thickness of 1.2 mm or less, and its maximum point strength is higher than 43.0 N / 50 mm. Since the triboelectric non-woven fabric according to the present invention has a maximum point strength higher than 43.0 N / 50 mm, for example, it can be punched in a state where tension is applied, processed to have a three-dimensional shape such as pleats, or used for an air filter or a mask. 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 non-woven 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)
The length of the test piece (shape: rectangle, long side: length that can be measured by the constant-speed extension type tensile tester described later) so that the machine direction (transportation direction at the time of manufacture) and the long side direction coincide with each other from the object to be measured. A short side (50 mm), which is longer than 100 mm, was collected. Then, the collected test piece is subjected to a constant-speed extension type tensile tester (manufactured by Orientec, Tensilon, initial grip interval: 100 mm, tensile speed: 300 mm / min), and the long side of the test piece is 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.

Further, for the object 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 having the longest fiber length excluding the long fiber among the constituent fibers. A test piece collected from the object to be measured is provided to a fast 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 maximum point strength (unit: N / 50 mm) of the object to be measured can be obtained by securing an initial gripping interval of 10 mm or more and performing 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 a plurality of short sides (50 mm) that are 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 of 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 extension 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 of the short side length of the measurement object obtained by the measurement was 1N. In this case, it can be calculated that the maximum point strength of the object to be measured is 5N / 50mm by conversion.

In order to obtain each of the above-mentioned values, a triboelectric non-woven fabric (test piece) can be collected from an air filter or a mask. At that time, a section is collected from a portion other than the welded portion of the air filter or mask which has been made into 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 non-woven fabric according to the present invention, the portion where the triboelectric fibers rub against each other is 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 of the constituent fibers on one main surface side of the charged nonwoven fabric are unevenly distributed, 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 non-woven fabric according to the present invention and the charged non-woven fabric obtained 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, an air filter or mask having excellent collection efficiency can be realized.

Next, a method for producing a triboelectric nonwoven fabric capable of producing the triboelectric nonwoven fabric according to the present invention will be described. The description of 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 non-woven 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 the fibers. A method of preparing a web, or a method of preparing a web in which each fiber is mixed at a required blending ratio by using direct spinning such as a melt-blown non-woven fabric, a spunbonded non-woven fabric, or an electrostatically spun non-woven 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 binders and adhesive fibers, the web may contain a triboelectric non-woven fabric having a large amount of charge by efficiently rubbing the triboelectric fibers against each other in the charging method according to the present invention. It is preferably free of binders and adhesive fibers, and is preferably a web 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 the 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 includes (2) a step of subjecting a web to a water flow entanglement treatment to prepare a water flow entangled web.

In the water flow entanglement treatment applied to the web, the strength of the water flow and the spacing and arrangement of the nozzles that radiate the water flow are adjusted 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 entangled web prepared in this way 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 the water flow entangled web is deformed in the thickness direction in a direction perpendicular to the thickness direction. Therefore, it has a step of rubbing the constituent fibers of the water flow entangled web.

In the method for producing a triboelectric non-woven 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. .. A 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 the water flow entanglement web is provided between the two rollers adjusted so as to have a clearance thinner than the thickness of the water flow entanglement web.
-The member is placed between 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.
-A plate, rod, conveyor, 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 for the clearance formed by a member and a roller, etc.
And so on.

The length of the clearance may be 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 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 pressurizing member (hereinafter sometimes referred to as the pressurizing member) used to deform the water flow entangled web such as a roller or conveyor 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 concrete example,
-By contacting the water flow entangled web with the surface of the roller and changing the transport direction of the water flow entangled web before contacting the roller and the transport direction of the water flow entangled web after contacting the roller, the contact is made. 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 non-woven 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 / absence of rotation, the rotation speed, and the rotation direction of the roller can be appropriately selected. 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 may be different combinations from each other. Further, the speed at which the transport 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 material can be produced. Adjust appropriately so that the entangled web does not crack, break, or change its physical properties unintentionally.

In the method for producing 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, "applying tension 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 pressure member. Rather than the tension acting in the direction perpendicular to the thickness direction of the web, the thickness direction of the water entangled web acting on the water entangled web after the water entangled 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,
・ Punching the water entangled web while applying tension to the water entangled web after it comes into contact with the pressurizing member in a direction perpendicular to the thickness direction of the water entangled web is used for the next process. 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, if the directions are different from each other, tension can be applied more effectively in the thickness direction of the water flow entangled web and in 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 non-woven 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 as 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) in a direction or a direction other than the transfer direction perpendicular to the thickness direction and the transfer 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 studies by the present inventors, an attempt was made to reduce the thickness of the triboelectric non-woven fabric prepared by performing the needle punching treatment by subjecting it to the calendar treatment, 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 simply a superposition of the illustrated material and the triboelectric non-woven fabric, it can be bonded by bonding 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.

The outer shape of the triboelectric non-woven fabric and the filter material provided with the triboelectric non-woven fabric can be adjusted as appropriate, and is not particularly limited. 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 non-woven fabric and the triboelectric non-woven 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 supplying them to a card machine. Then, a criss-cross-ray web was prepared by laminating a one-way web and a cross-lay web.
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 crisscross ray web to the other main surface side (B). 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 crisscross ray web to the one main surface side (A). provided. Then, the water contained in the crisscross ray web was removed by subjecting the crisscross ray 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 crisscross ray web used was increased. A triboelectric non-woven 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 transfer 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 transfer direction are parallel to each other. Then, it was conveyed at a transfer speed of 25.0 m / min. Then, the water flow entangled web is brought into contact with a metal roller (roller rotation direction: rotation direction that enables the water flow entangled web to be transported downstream in the transport direction) whose clearance with the 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 transport conveyor in contact with the water flow entangled web and the metal roller. By providing it, the friction between the triboelectric fibers was 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 non-woven 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 non-woven fabric manufactured as described above. In the following table, 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 "oil agent percentage (mass%)" column.
The ventilation resistance (unit: Pa) and the collection efficiency (unit:%) were determined by applying the water flow entangled web of the reference example and each triboelectric non-woven fabric to the following measurement methods. Further, a QF value capable of evaluating the filter performance was calculated from the obtained values of the ventilation 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 Shibata 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 of the piece was measured, and the ventilation resistance (unit: Pa) of the test piece was determined 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 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 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 existing on the upstream side and the downstream side of the test piece were measured using a light scattering dust concentration meter, 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 with a mask filter, and the more energy and equipment load can be reduced with an air filter, which means that the filter performance is rich. Therefore, the ventilation 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 value can be adjusted as appropriate, but 0.5 Pa or more is realistic.

Further, 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 ventilation resistance (unit: Pa) and the collection efficiency (unit:%) calculated as described above into the following equation. 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 non-woven 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 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) 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 non-woven fabrics prepared in Comparative Example 1 and Comparative Example 2, in order to prepare a thin triboelectric non-woven fabric (for example, a triboelectric non-woven fabric having a thickness of 1.2 mm or less), triboelectric charging is performed. It turned out that it was necessary to lighten the texture of the web mixed with fibers. However, based on the results of comparing the maximum point strengths of the triboelectric non-woven fabrics prepared in Comparative Example 1 and Comparative Example 2, the triboelectric non-woven 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 non-woven 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). The triboelectric non-woven fabric (which has a maximum point strength higher than 43.0 N / 50 mm) could not be prepared.

In response to the above findings, the triboelectric non-woven fabrics prepared in Examples 1 and 2 are triboelectric non-woven 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 non-woven fabric according to the present invention, the constituent fibers of the water flow entangled web can be rubbed against each other to be triboelectric without performing needle punching on the web, so that the web is thin and has excellent strength. This is 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 non-woven fabric was prepared in the same manner as in Example 1 except that the water flow entangled web prepared in this manner 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 non-woven 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 2 shows various physical properties of each triboelectric non-woven fabric manufactured as described above. In Table 2, the results of Example 1 are also shown for easy understanding.

The triboelectric non-woven fabrics prepared in Examples 3 to 4 were all triboelectric non-woven fabrics having physical properties of 1.2 mm or less in thickness and higher maximum point strength 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 arranged so that the fiber orientation of the fiber layer A constituting the water flow entangled web is parallel to the transport direction, and the surface of the calendar roll is made of a metal material (rotation direction: transport direction of the water flow entangled web). The water flow entangled web was pressurized in the direction of rotation so that it could be transported to the downstream side and the linear pressure was 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 non-woven 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 supplying 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 unidirectional 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 unidirectional web was removed by subjecting the unidirectional 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 non-woven fabric was prepared in the same manner as in Example 5 except that the water flow entangled web prepared in this manner 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 non-woven fabric was prepared in the same manner as in Example 5 except that the water flow entangled web prepared in this manner was used.
Table 3 shows various physical properties of each triboelectric non-woven fabric manufactured as described above.

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

Furthermore, 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 above one direction are laminated. It has been found that the triboelectric non-woven fabric having a high collection efficiency can be provided by having the structure.
-From the results of comparing Example 5 and Example 8, it was found that the triboelectric fibers constituting the triboelectric non-woven fabric contain a non-hydrophilic oil agent, so that the triboelectric non-woven fabric having high collection efficiency can be provided. bottom.
In each triboelectric non-woven 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 the needle punching process, the triboelectric nonwoven fabric prepared in each example does not have holes derived from the needle processing such as through holes by the needle punching process.

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 friction-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 non-woven 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 (2)

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. A method for producing 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
A method for producing a triboelectric non-woven fabric.