JPWO2019198829A1 - Non-woven fabric, sound absorbing material, and oil adsorbent - Google Patents

Abstract

An object of the present invention is to provide a non-woven fabric having excellent water repellency, particularly excellent water repellency even under harsh conditions such as high temperature and humidity, and further, in terms of water repellency and sound absorption using the non-woven fabric. It is to provide an excellent sound absorbing material. Another object of the present invention is to provide an oil adsorbent having excellent oil absorption using the non-woven fabric. The non-woven fabric of the present invention is a non-woven fabric containing water-repellent pulp and a heat-sealing adhesive, and the water-repellent pulp satisfies the following (1). (1) In the water absorption test specified in JIS L1907: 2010 standard, the settling start time is 30 seconds or more.

Description

The present invention relates to a non-woven fabric, a sound absorbing material, and an oil adsorbent.

Currently, non-woven fabrics are used in a wide range of fields, from consumer products such as clothing, daily necessities, and medical products to industrial products. In addition, the purpose of use is diverse, and it is used not only as a cloth but also as a filter, an absorbent / adsorbent, a sound absorbing material, a heat insulating material, and the like.
Among these, sound absorbing materials are used in home appliances and the like to absorb noise and vibration generated by motors, compressors, and the like.

The above-mentioned non-woven fabric is required to have water repellency. For example, when the non-woven fabric is used as a sound absorbing material in an environment where dew condensation occurs, the water repellency suppresses deterioration of performance due to water absorption. Furthermore, it also has the effect of suppressing the growth of microorganisms such as mold.
Patent Document 1 describes a non-woven fabric made of organic fibers and an air volume measured based on JIS L1096 of 0.01 to 30 cc / cm ² / sec, and at least two layers of a skin material treated with a water repellent. A water-repellent sound-absorbing material characterized by being laminated with each other is described.

Japanese Unexamined Patent Publication No. 2005-208599

An object of the present invention is to provide a nonwoven fabric having excellent water repellency, particularly excellent water repellency even under harsh conditions such as high temperature and humidity. Furthermore, an object of the present invention is to provide a sound absorbing material having excellent water repellency and sound absorbing property using the non-woven fabric. Another object of the present invention is to provide an oil adsorbent having excellent oil absorption using the non-woven fabric.

The present inventors have found that the above-mentioned problems can be solved by a non-woven fabric containing a specific water-repellent pulp and a heat-sealing adhesive.
That is, the present invention relates to the following <1> to <13>.
<1> A non-woven fabric containing a water-repellent pulp and a heat-sealing adhesive, wherein the water-repellent pulp satisfies the following (1).
(1) In the water absorption test specified in JIS L1907: 2010 standard, the sedimentation start time is 30 seconds or more. <2> The water-repellent pulp is further at least one of the following (2) to (5). The non-woven fabric according to <1>, which satisfies the above conditions.
(2) The amount of pulp water retained in the water retention test is 15 g or less (3) The amount of liquid flow in the liquid flow test is 35 g or more (4) The swelling rate when water is dropped is 20% under microscopic observation. (5) The non-woven fabric according to <1> or <2>, wherein the water absorption in the tea bag test is 10 (g / g) or less. <3> The non-woven fabric is a dry non-woven fabric.
<4> The non-woven fabric according to any one of <1> to <3>, wherein the Krem water absorption degree measured in accordance with JIS P8141: 2004 is less than 30 mm.
<5> Any of <1> to <4>, wherein the non-woven fabric is subjected to a washing treatment in which the non-woven fabric is washed with running water for 1 hour, and then the Krem water absorption measured in accordance with JIS P8141: 2004 is less than 30 mm. The non-woven fabric described.
<6> After subjecting the non-woven fabric to a heat resistance test in which the non-woven fabric is exposed to an environment of 100 ° C. for 1000 hours, the Krem water absorption measured in accordance with JIS P8141: 2004 is less than 30 mm, <1> to <5. > The non-woven fabric according to any one of.
<7> After subjecting the non-woven fabric to a high-temperature and high-humidity test in which the non-woven fabric is exposed to an environment of 85 ° C. and 95% RH for 600 hours, the Krem water absorption degree measured in accordance with JIS P8141: 2004 is less than 30 mm. , <1> to <6>.
<8> Using the non-woven fabric, 1 hour at -10 ° C and 1 hour at 60 ° C are set as one cycle, which is subjected to a heat cycle test in which 30 cycles are repeated, and then measured according to JIS P8141: 2004. The non-woven fabric according to any one of <1> to <7>, wherein the Krem water absorption is less than 30 mm.
<9> A sound absorbing material comprising the non-woven fabric according to any one of <1> to <8>.
<10> The sound absorbing material according to <9>, wherein the content of the water-repellent pulp in the non-woven fabric is 50% by mass or more.
<11> The sound absorbing material according to <9> or <10>, which has a resin layer on at least one surface of the nonwoven fabric.
<12> An oil adsorbent comprising the non-woven fabric according to any one of <1> to <8>.
<13> The oil adsorbent according to <12>, wherein the content of the water-repellent pulp in the non-woven fabric is 50% by mass or more.

According to the present invention, it is possible to provide a non-woven fabric having excellent water repellency, particularly excellent water repellency even under harsh conditions such as high temperature and humidity. Further, according to the present invention, it is possible to provide a sound absorbing material having excellent water repellency and sound absorbing property using the non-woven fabric. Further, according to the present invention, it is possible to provide an oil adsorbent having excellent oil absorption using the non-woven fabric.

FIG. 1 shows the measurement results of the vertically incident sound absorption coefficient at each frequency. FIG. 2 shows the results of the dropping test in the oil absorption / water absorption test.

[Non-woven fabric]
The non-woven fabric of the present invention is a non-woven fabric containing water-repellent pulp and a heat-sealing adhesive, and the water-repellent pulp satisfies the following (1).
(1) In the water absorption test specified in JIS L1907: 2010 standard, the water-repellent pulp having a sedimentation start time of 30 seconds or more further satisfies at least one of the following (2) to (5). Is preferable.
(2) The amount of pulp water retained in the water retention test is 15 g or less (3) The amount of liquid flow in the liquid flow test is 35 g or more (4) The swelling rate when water is dropped is 20% under microscopic observation. (5) The amount of water absorbed in the tea bag test is 10 (g / g) or less Conventionally, in order to make the non-woven fabric water-repellent, the non-woven fabric itself is made of an organic synthetic fiber having no water absorption. A method, a method of impregnating a non-woven fabric with a liquid containing a water-repellent agent as described in Patent Document 1, a method of spraying a liquid containing a water-repellent agent onto the non-woven fabric, and the like have been adopted.
However, the method of treating the non-woven fabric with a water-repellent agent has insufficient coating property of the water-repellent agent, and sufficient water repellency cannot be obtained. Therefore, there is a problem that the water repellency is lowered.
Further, when the non-woven fabric itself is made of organic synthetic fiber having no water absorption, since the fiber surface of the organic synthetic fiber is smooth, the sound absorbing material provided with the non-woven fabric made of pulp fiber having the same thickness, density and specific gravity. There is a problem that the sound absorption property is inferior to that of the above. Further, although the pulp fiber has high sound absorption, it also has high water absorption, so that there is a problem that sufficient water repellency cannot be imparted by the method of treating the non-woven fabric with a water repellent agent. Further, in the method of treating the non-woven fabric with a water repellent, there is a problem that the water repellent covering the surface hinders the sound absorption property. When the non-woven fabric is treated with a water repellent, in the case of a porous sound absorbing material, the sound absorption property may be hindered by coating the porous material with the water repellent, and the non-woven fabric is treated with the water repellent. In the case of treatment, the sound absorption property may be hindered by partially covering the voids between the fibers.

As a result of diligent studies, the present inventors have solved the above-mentioned problems with a non-woven fabric containing a water-repellent pulp having a specific water repellency and a heat-sealing adhesive, and have achieved high water repellency and water repellency durability. We have found that a non-woven fabric having excellent sound absorption can be provided, and have completed the present invention. Furthermore, it has been found that the above-mentioned non-woven fabric is also useful as an oil adsorbent which is selective for oil and has excellent adsorptivity.
That is, the non-woven fabric containing the water-repellent pulp and the heat-sealing adhesive has high sound absorption as compared with the case where the non-woven fabric is treated with the water-repellent agent because the pulp itself is provided with water repellency. It is considered that a non-woven fabric having excellent durability was obtained. In the present invention, since the non-woven fabric itself is produced using water-repellent pulp, the bond between the water-repellent agent and the pulp is stronger and repellent as compared with post-processing in which the non-woven fabric is treated with a water-repellent agent. It is considered that a non-woven fabric having excellent water durability was obtained.
As described above, a sound absorbing material having a sound absorbing property equivalent to that of a pulp sound absorbing material and also having water repellency has been found for the first time.
Further, as described above, since the nonwoven fabric of the present invention has excellent water repellency, it does not adsorb water and has selective adsorptivity to oil, so that it can be used as an oil adsorbent having excellent oil adsorbability. It is considered that it also has the function of.
Hereinafter, the present invention will be described in more detail.

<Water repellent pulp>
The non-woven fabric of the present invention contains water-repellent pulp, and the water-repellent pulp preferably satisfies the following (1) and further, at least one of the following (2) to (5). The non-woven fabric of the present invention is characterized in that the non-woven fabric is produced using water-repellent pulp rather than being treated with a water-repellent agent.
(1) In the water absorption test specified in JIS L1907: 2010 standard, the settling start time is 30 seconds or more (2) The pulp water retention amount in the water retention test is 15 g or less (3) The liquid in the liquid flow test The flow amount is 35 g or more (4) The swelling rate when water is dropped under a microscope is 20% or less (5) The water absorption amount in the tea bag test is 10 (g / g) or less. , The above (1) to (5) will be described in detail.

(1) In the water absorption test specified in JIS L1907: 2010 standard, the sedimentation start time is 30 seconds or more. More specifically, the water absorption test (precipitation method) specified in JIS L1907: 2010 standard is applied. And measure. After the sample is floated in a water tank filled with water at 20 ° C. ± 2 ° C., the time until the sample becomes wet and begins to settle in water (settlement start time) is measured.
In the present invention, the water-repellent pulp has a settling start time of 30 seconds or more, preferably 60 seconds or more.

(2) Pulp water retention amount in the water retention test This test measures how much water the pulp was able to retain out of 40 cc (40 g) of water, and the pulp water retention amount is The higher the amount, the higher the water absorption. Specifically, it is measured by the following method.
An acrylic bottom surface with an inner diameter that fits snugly is installed in an acrylic frame (hollow square columnar) with a length and width of 10 cm and a height of 6 cm. The degree of adhesion is such that when water is put into the frame with the bottom surface, the water seeps out slightly.
Separately, weighed filter paper (filter paper sufficient to absorb 40 cc of water) is laid under the frame on which the bottom surface is installed. 2 g of pulp fiber is uniformly put in this frame, 40 cc of water is added to the whole, and after 1 minute, 700 gf of an acrylic weight having substantially the same size as the inner diameter of the frame is placed and a load is gently applied to the pulp fiber. After 1 minute, the mass of the filter paper under the frame is measured, the amount of water exuding from the frame is measured, and the difference from the added water of 40 g is defined as the pulp water retention amount (g). That is, the amount of pulp water retained is represented by the following formula (a).
Pulp water retention (g) = 40 (g) -Amount of exuded water (g) Formula (a)
The amount of exuded water is measured from the difference between the mass of the filter paper measured before the test and the mass of the water-absorbed filter paper after the test.
The amount of water retained in the water-repellent pulp is preferably 12.5 g or less, more preferably 10 g or less, still more preferably 7.5 g or less, still more preferably 5 g or less.

(3) On a wire mesh having a liquid flow amount of 35 g or more in the liquid flow test, an acrylic cylinder having 5 drain ports with a hole diameter of 3 mm on the bottom surface and a cross shape and an inner diameter of 3 cm is placed, and 1 g of pulp fiber is placed in height. After compressing to 4 cm (density 0.035 g / cm ³ ), 50 cc of water is added at a time, and the amount of discharged water is measured to obtain the amount of liquid flow.
The larger the amount of liquid flowing, the lower the water absorption and the better the water repellency.
The amount of the water-repellent pulp flowing is preferably 37.5 g or more, more preferably 40 g or more, still more preferably 42.5 g or more, still more preferably 45 g or more.

(4) Under a microscope, the swelling rate when water is dropped is 20% or less. Under a microscope, the swelling rate when water is dropped on water-repellent pulp is 20% or less. The swelling rate is preferably 15% or less, more preferably 10% or less, still more preferably 5% or less, still more preferably 3% or less, still more preferably 0%.
The swelling rate is measured by the following method. Specifically, 3 to 5 mg of pulp fiber is placed on the preparation, and about 0.1 ml of water is added with a dropper. After leaving it for about 5 minutes, tilt the slide and remove the water that is not absorbed by the pulp fibers with a Kimwipe or the like. The fiber diameter of the pulp fiber is measured from the micrographs before and after the dropping of water, and the swelling rate is calculated by the following formula.
Swelling rate = {fiber diameter (width dimension) of pulp fiber after dropping water-fiber diameter (width dimension) of pulp fiber before dropping water} ÷ fiber diameter (width dimension) of pulp fiber before dropping water (width dimension) x 100 (% )
Here, the state where the swelling rate is 0% means that the water and the pulp fibers do not blend with each other, the water remains spherical due to surface tension, and the fibers are placed on the water droplets, or the fibers have spherical water droplets. It means the state of adhesion.

(5) Water absorption in the tea bag test is 10 (g / g) or less The water absorption when the water-repellent pulp is subjected to the tea bag test is 10 (g / g) or less, preferably 7.5 (. It is g / g) or less, more preferably 5 (g / g) or less, still more preferably 3 (g / g) or less.
The water absorption is measured by the following tea bag test. Specifically, about 5 g of pulp fiber is put into a tea bag (9.5 cm x 7 cm, non-woven fabric using polyester as the main fiber material, Tokiwa's tea bag M, manufactured by Tokiwa Kogyo Co., Ltd.) and put on the tip of the tea bag. , Attach the weight (500g) with a string. Place a tea bag with a weight in a beaker filled with water. Fill the tea bag to a height where the entire tea bag is completely submerged. After soaking the tea bag for 5 minutes, remove it from the water and hang it in the air for 5 minutes to drain the water. The mass of the tea bag (containing pulp fiber) after draining is measured, and the amount of water absorption is calculated by the following formula. Here, since the amount of water absorbed by the tea bag itself is very small, it does not need to be considered.
Water absorption (g / g) = (mass of pulp fiber-containing tea bag after draining-mass of pulp fiber-containing tea bag before immersion in water) ÷ pulp fiber mass before test Here, the water absorption is 1 times. The state means that the water and the pulp fibers do not blend with each other, the water remains spherical due to the surface tension, and the fibers are placed on the water droplets, or the spherical water droplets are attached to the fibers.

In the present invention, the water-repellent pulp preferably satisfies the above (1) and further satisfies at least one of (2) to (5).
The water-repellent pulp preferably satisfies at least (1), more preferably at least (1) and (2), and even more preferably at least (1), (2) and (3). It is even more preferable to satisfy all of 1) to (5).

The water-repellent pulp contains pulp fibers and may be directly or indirectly treated with a water-repellent agent, or may have water repellency by selecting a raw material for the pulp fibers. .. Pulp fibers are fibers having an irregularly bent shape and a crimp-like morphology, and also fibers having a hollow tubular morphology having pores (lumens) occupied by the protoplasm of plant cells. is there. The use of water-repellent pulp is preferable from the viewpoint that excellent sound absorption can be obtained and the environmental load can be further reduced.
Pulp fibers include wood pulp (coniferous tree pulp, broadleaf tree pulp), rug pulp, linter pulp, linen pulp, non-wood pulp such as 楮, sansho, and ganpi pulp, and pulp such as used paper pulp; these pulps are used as raw material pulps. Fluff pulp in which raw material pulp is defibrated into fibers by mechanical treatment;
As the raw material pulp, fine fiber pulp is preferable from the viewpoint of sound absorption, but the sound absorption may be inferior when the density is high. Further, from the viewpoint that a non-woven fabric having excellent water repellency can be easily obtained, it is preferable to use wood having a high alkane content such as eucalyptus or wood having a high paraffin content as the raw material pulp.
Further, fluff pulp is preferable from the viewpoint of excellent sound absorption.
The method for pulping the raw material pulp is not particularly limited, and the raw material pulp may be pulped by a conventionally known method.

In the present invention, the water-repellent pulp may be the above-mentioned fiber pulp treated with a water-repellent agent. The water repellent is not particularly limited, and for example, various waxes; higher fatty acid derivatives; synthetic resins such as polyolefin resins, polyamide resins, and polyamine resins; fluororesins such as polytetrafluoroethylene and polychlorotrifluoroethylene; Silicone resins such as polymethyl hydrogensiloxane and polydimethylsiloxane; chromate; zirconium salt; and the like can be mentioned. Further, rosin sizing agents, synthetic sizing agents, petroleum resin sizing agents, styrene sizing agents, neutral rosin sizing agents, alkenyl succinic anhydride, alkyl keten dimers and the like can also be used as water repellents in the present invention. is there.
Specific examples of the water repellent include plant waxes such as carnauba wax, cotton wax, wood wax, and rice wax, animal waxes such as beeswax and lanolin, and waxes extracted from montan wax, ozokerite, ceresin, and oil shells. Mineral waxes such as, and petroleum waxes such as paraffin, microcrystallin, and petrolatum can be mentioned. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fisher Tropsch wax and polyethylene wax, higher fatty acid amides such as 12-hydroxystearic amide, stearic acid amide, phthalic anhydride and chlorinated hydrocarbons, and esters. , Ketone, ether and other synthetic waxes can also be used. Further, a crystalline polymer having a long alkyl group in the side chain can be mentioned.

In the nonwoven fabric of the present invention, the content of the water-repellent pulp is not particularly limited, but from the viewpoint of imparting water repellency to the nonwoven fabric, it is preferably 10% by mass or more, more preferably 15% by mass or more, still more preferably 30% by mass or more. , More preferably 50% by mass or more, and even more preferably 70% by mass or more. The upper limit is not particularly limited, but is preferably 95% by mass or less, more preferably 90% by mass or less, from the viewpoint of immobilizing the water-repellent pulp with a hot-melt adhesive described later.
The content of the water-repellent pulp with respect to the total of the water-repellent pulp and the heat-sealing adhesive is preferably 10% by mass or more, more preferably 15% by mass or more, and further, from the viewpoint of imparting water repellency to the non-woven fabric. It is preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 70% by mass or more. The upper limit is not particularly limited, but is preferably 95% by mass or less, more preferably 90% by mass or less, from the viewpoint of maintaining the content of the heat-sealing adhesive described later.

<Heat-sealing adhesive>
The non-woven fabric of the present invention contains a heat-sealing adhesive. The heat-sealing adhesive may be supplied as a heat-sealing powder in the form of particles, may be supplied by spraying in a state of being dissolved or dispersed in a solvent, or as a heat-sealing fiber. , Although it may be supplied in the form of fibers, it is preferable that the heat-sealing adhesive is in the form of fibers and is supplied to the non-woven fabric. That is, the heat-sealing adhesive is more preferably a heat-sealing fiber.
Examples of the components of the heat-sealing adhesive include polyethylene (PE), polypropylene (PP), polyethylene / vinyl acetate copolymer, polyamide, polyester such as polyethylene terephthalate (PET), and the like. It is not limited.

The heat-sealing fiber is not particularly limited as long as it functions as a binder by melting at least a part of the heat-sealing fiber by heat treatment after forming the web.
As the heat-sealing fiber, a heat-sealing fiber having a core-sheath structure or the like, which is obtained by combining two types of resins having different melting points and in which the fiber is partially melted, may be used. The heat-sealing fiber having a core-sheath structure has a structure in which a sheath made of a resin having a low melting point is formed on the outer periphery of a core made of a resin having a high melting point. Examples thereof include a form in which the above resins are combined (PET / PET composite fiber, PE / PE composite fiber, PP / PP composite fiber, PE / PET composite fiber, PP / PET composite fiber, PE / PP composite fiber).

In the nonwoven fabric of the present invention, the content of the heat-sealing adhesive is not particularly limited, but is preferably 5% by mass or more, more preferably 10% by mass or more, from the viewpoint of imparting strength as a nonwoven fabric. Further, from the viewpoint of maintaining the content of the water-repellent pulp, it is preferably 90% by mass or less, more preferably 85% by mass or less, still more preferably 70% by mass or less, still more preferably 50% by mass or less, still more preferably. It is 30% by mass or less.
Further, the content of the heat-sealing adhesive with respect to the total of the water-repellent pulp and the heat-sealing adhesive is preferably 5% by mass or more, more preferably 10% by mass, from the viewpoint of imparting strength as a non-woven fabric. That is all. Further, from the viewpoint of maintaining the content of the water-repellent pulp, it is preferably 90% by mass or less, more preferably 85% by mass or less, still more preferably 70% by mass or less, still more preferably 50% by mass or less, still more preferably. It is 30% by mass or less.

<Other ingredients>
The non-woven fabric of the present invention may contain other components in addition to the water-repellent pulp and the heat-sealing adhesive described above.
Specific examples thereof include functional powders, functional fibers, and functional liquids. As a functional powder, a functional fiber, or a functional liquid, one or more functions such as a deodorant function, an antibacterial function, an antivirus function, an antiallergen function, an antifungal function, an aroma function, and a flame retardant component are used. Preferably having, for example, zeolite, activated charcoal, chitin, chitosan, scallop shell, titanium oxide, titanium dioxide, magnesium oxide, plant extract, mushroom extract, catechin, flavonol, cyclodextrin, collagen fiber, iron oxide, citrate. Examples thereof include flame retardant particles such as acid, zinc pyrithione, copper pyrithione, hinokithiol, eucalyptus extract, halogen bromine-based, hydrated metal-based, antimony oxide-based, phosphorus-based, and phosphorus / nitrogen-based condensates.

When the non-woven fabric of the present invention contains other components, the total amount of the other components in the non-woven fabric may be appropriately selected within a range that does not affect the water repellency of the non-woven fabric, and is not particularly limited, but is preferably 90 mass. % Or less, more preferably 80% by mass or less, still more preferably 70% by mass or less, still more preferably 50% by mass or less, still more preferably 40% by mass or less, still more preferably 30% by mass or less, still more preferably 20. It is mass% or less, more preferably 10 mass% or less. The lower limit of the content of other components is not particularly limited.

In the present invention, the average fiber diameter of all the fibers (raw material fibers) constituting the non-woven fabric is preferably 5 to 80 μm, more preferably 10 to 60 μm. It is preferable that the average fiber system of the fibers constituting the non-woven fabric is within the above range because it is excellent in sound absorption. The average fiber diameter can be measured by microscopic observation in the case of synthetic fibers, and in the case of pulp fibers, the average fiber diameter should be measured by the result of image analysis by a fiber length measuring device (for example, KAJAANI Fiber Lab.). Can be done.

Further, in the present invention, the average fiber length of all the fibers (raw material fibers) constituting the non-woven fabric is preferably 0.5 to 150 mm, and when the non-woven fabric is an air-laid non-woven fabric, all the fibers constituting the non-woven fabric. The average fiber length of the (raw material fiber) is preferably 0.5 to 10 mm, more preferably 0.5 to 6 mm. When the average fiber length of all the fibers constituting the non-woven fabric is within the above range, the bulk density of the non-woven fabric is small and the sound absorption is excellent, which is preferable. In the case of synthetic fibers, the average fiber length can be measured by microscopic observation, and in the case of pulp fibers, the fiber length can be measured by a fiber length measuring device (for example, KAJAANI Fiber Lab.).

<Manufacturing method of non-woven fabric>
In the present invention, the method for producing a non-woven fabric goes through a web forming step of forming a sheet-like web from raw material fibers containing at least water-repellent pulp, and a fiber bonding step of binding the raw material fibers in the obtained web. The method is preferred.

In the present invention, the non-woven fabric may be either a wet non-woven fabric or a dry non-woven fabric, and specific examples thereof include air-laid non-woven fabrics, air-through non-woven fabrics, spunlace non-woven fabrics, needle punch non-woven fabrics, and resin-bonded non-woven fabrics. From the viewpoint that it is difficult to disperse the water-repellent pulp in water, the non-woven fabric is preferably a dry non-woven fabric, that is, a non-woven fabric obtained by a dry production method, and more preferably an air-laid non-woven fabric.
When the non-woven fabric is an air-laid non-woven fabric, it is not necessary to disperse the water-repellent pulp in water, and in the air-laid non-woven fabric, the raw material fibers are three-dimensionally and randomly oriented, so that many voids are formed and the non-woven fabric has high sound absorption. Is obtained.

The air-laid non-woven fabric is a non-woven fabric in which a web is formed by an air-laid method in which fibers constituting the non-woven fabric are three-dimensionally and randomly laminated by using an air flow.
The air-laid nonwoven fabric is produced, for example, as follows. First, an air-permeable carrier sheet is placed on a mesh-shaped endless belt, and fibers constituting the non-woven fabric are deposited on the air-permeable carrier sheet while being dispersed in air by an air-laid web forming device to form a web. To do. Then, it is heat-bonded by a heat-sealing adhesive contained in the web by heating (thermal bond method).
The heat treatment of the formed air-laid web may be performed by a general thermal bond method, and examples thereof include a method of introducing the air-laid web into a heating furnace, a method of treating the air-laid web with hot air, and the like.
Further, a sheet may be further arranged on the surface of the non-woven fabric before or after heat fusion. The sheet is arranged on another surface (front surface) when the surface on which the air-permeable carry sheet is arranged is the back surface. Here, the sheet to be arranged on the surface is not limited to the air-permeable sheet, and various sheets can be arranged. The sheet on the front surface may be the same as the air permeable carry sheet on the back surface.

Hot air treatment includes a method in which the web is heat-treated by passing through a through-air dryer equipped with a rotating drum having air permeability on the peripheral surface (hot air circulation rotary drum method), and the web can allow hot air to penetrate the web. Examples thereof include a method of heat treatment by passing through a box type dry (hot air circulation conveyor oven method).
The heat treatment temperature may be equal to or higher than the melting point of the heat-sealing adhesive. When the heat-sealing adhesive is composed of two or more kinds of resins, the temperature may be equal to or higher than the melting point of the resin having the lowest melting point. When heated to a temperature equal to or higher than the melting point of the heat-sealing adhesive, the heat-sealing adhesive melts, and the fiber raw materials containing the water-repellent pulp are bonded to each other via the melted heat-sealing adhesive.

After the fiber bonding step, a hot press treatment may be performed for the purpose of finely adjusting the density of the formed non-woven fabric. In that case, the press pressure is a linear pressure, preferably 44 kg / cm or less, more preferably 10 kg / cm or less, which is lower than the heat press step generally performed as a fiber bonding step for binding fibers to each other. It is said.

A non-woven fabric can be obtained by peeling the air-permeable carrier sheet from the non-woven fabric obtained as described above. The air permeable carrier sheet may be left as it is without being peeled off. When leaving as it is without peeling, it is preferable to use a water-repellent carrier sheet as the air-permeable carrier sheet.

In the present invention, the basis weight, density, and thickness of the non-woven fabric are not particularly limited and may be appropriately selected depending on the required performance.
When the non-woven fabric of the present invention is used as a sound absorbing material, the basis weight, density, and thickness may be set from the viewpoints of, for example, the frequency band in which sound absorption is desired, the installation space of the sound absorbing material, and the like. When the non-woven fabric of the present invention is used as a sound absorbing material with a thickness of 3.0 to 6.0 mm, it is preferably ^{rice tsubo: 400 to 500 g / m 2} and a density of 0.05 to 0.1 g / cm ^3.

The non-woven fabric of the present invention preferably has a Krem water absorption of less than 30 mm as measured in accordance with JIS P8141: 2004. Here, the Krem water absorption degree means the height (mm) in which the non-woven fabric (sample) is vertically immersed in water and the water rises in 10 minutes due to the capillary phenomenon.
The non-woven fabric of the present invention has a Krem water absorption rate of more preferably 20 mm or less, further preferably 10 mm or less, still more preferably 5 mm or less, still more preferably 1 mm or less, still more preferably 0 mm.
According to the findings of the present inventors, when the non-woven fabric is made of hydrophobic organic synthetic fiber, the Krem water absorption is 30 mm or more due to the capillary phenomenon.
Since the Krem water absorption depends on the density, the non-woven fabric having a low density tends to have a low Krem water absorption. However, in the porous sound absorbing material, in order to obtain a constant sound absorbing effect, the total amount of the porous body itself for converting sound into energy is required, and under conditions where the thickness is restricted, it is constant. Requires the density of. Therefore, it when comparing Klemm water absorbency, if there is a thick seen sound absorbing effect, it is preferable that the density of the nonwoven fabric is 0.03 g / cm ³ or more and 0.05 g / cm ³ or more More preferably, it is 0.07 g / cm ³ or more.

The non-woven fabric of the present invention is less likely to deteriorate in water repellency even by washing, and after being subjected to a water washing treatment in which the non-woven fabric is washed with running water for 1 hour, the Krem water absorption degree measured in accordance with JIS P8141: 2004 is less than 30 mm. It is preferable to have.
Here, it is preferable to wash at a water temperature of 30 ° C. ± 2 ° C. using tap water. Under the above conditions, when the non-woven fabric is post-processed with a water-repellent agent, the water-repellent agent is reduced by the cleaning treatment, and the Krem water absorption tends to be higher. On the other hand, in the non-woven fabric of the present invention, the non-woven fabric is formed by using water-repellent pulp having water repellency, and the above-mentioned decrease in water repellency is unlikely to occur.
The Krem water absorption after the above-mentioned washing treatment is more preferably 20 mm or less, further preferably 10 mm or less, still more preferably 5 mm or less, still more preferably 1 mm or less, still more preferably 0 mm.

Further, the non-woven fabric of the present invention is less likely to deteriorate in water repellency even by a heat resistance test, and is measured in accordance with JIS P8141: 2004 after being subjected to a heat resistance test in which the non-woven fabric is exposed to an environment of 100 ° C. for 1000 hours. The water absorption of the non-woven fabric is preferably less than 30 mm.
The heat resistance test is performed by exposing the non-woven fabric to an environment of 100 ° C. for 1000 hours. When the non-woven fabric is post-processed with a water-repellent agent, or when a water-repellent sheet is attached to the non-woven fabric to impart water repellency, the water repellency is likely to be lowered by the heat resistance test. In particular, when a water-repellent sheet is laminated, the water-repellent sheet and the non-woven fabric may be peeled off to reduce the water repellency. On the other hand, in the non-woven fabric of the present invention, the non-woven fabric is formed by using water-repellent pulp having water repellency, and the above-mentioned decrease in water repellency is unlikely to occur.
The Clem water absorption of the non-woven fabric after the heat resistance test described above is more preferably 20 mm or less, further preferably 10 mm or less, still more preferably 5 mm or less, still more preferably 1 mm or less, still more preferably 0 mm.

Further, the non-woven fabric of the present invention is less likely to deteriorate in water repellency even in a high temperature and high humidity test, and after being subjected to a high temperature and high humidity test in which it is exposed to an environment of 85 ° C. and 95% RH for 600 hours, it is subjected to JIS P8141: 2004. The Krem water absorption measured in accordance with this is preferably less than 30 mm.
The high temperature and high humidity test is performed by exposing the non-woven fabric to an environment of 85 ° C. and 95% RH for 600 hours. When the non-woven fabric is post-processed with a water-repellent agent or when a water-repellent sheet is attached to the non-woven fabric to impart water repellency, the water repellency is likely to be lowered by the high temperature and high humidity test. In particular, when a water-repellent sheet is laminated, the water-repellent sheet and the non-woven fabric may be peeled off to reduce the water repellency. On the other hand, in the non-woven fabric of the present invention, the non-woven fabric is formed by using water-repellent pulp having water repellency, and the above-mentioned decrease in water repellency is unlikely to occur.
The Clem water absorption of the non-woven fabric after the above-mentioned high temperature and high humidity test is more preferably 20 mm or less, further preferably 10 mm or less, still more preferably 5 mm or less, still more preferably 1 mm or less, still more preferably 0 mm.

Further, the non-woven fabric of the present invention is less likely to deteriorate in water repellency even by a heat cycle test, and a heat cycle test in which 1 hour at -10 ° C and 1 hour at 60 ° C is set as one cycle, and this is repeated for 30 cycles. After serving, the Krem water absorption measured in accordance with JIS P8141: 2004 is preferably less than 30 mm.
The heat cycle test is carried out by repeating 30 cycles of the non-woven fabric at −10 ° C. for 1 hour and 60 ° C. for 1 hour as one cycle. When the non-woven fabric is post-processed with a water-repellent agent, or when a water-repellent sheet is attached to the non-woven fabric to impart water repellency, the water repellency tends to decrease by the heat cycle test. In particular, when a water-repellent sheet is laminated, the water-repellent sheet and the non-woven fabric may be peeled off to reduce the water repellency. On the other hand, in the non-woven fabric of the present invention, the non-woven fabric is formed by using water-repellent pulp having water repellency, and the above-mentioned decrease in water repellency is unlikely to occur.
The Clem water absorption of the non-woven fabric after the heat cycle test described above is more preferably 20 mm or less, further preferably 10 mm or less, still more preferably 5 mm or less, still more preferably 1 mm or less, still more preferably 0 mm.

[Sound absorbing material]
In the present invention, the non-woven fabric is preferably used as a sound absorbing material.
Further, the non-woven fabric of the present invention uses pulp fibers, and the surface shape of the pulp fibers is more complicated than that of organic synthetic fibers, and when sound waves pass through the non-woven fabric, the degree of maze becomes high and sound is produced. It is presumed that the efficiency of energy conversion into thermal energy is high, and as a result, high sound absorption is obtained.
The sound absorbing material of the present invention includes at least the non-woven fabric of the present invention, and may further include another layer on at least one surface of the non-woven fabric.
Since the sound absorbing material of the present invention includes the above-mentioned non-woven fabric of the present invention, it is excellent in water repellency, and as described above, its water repellency is maintained even by a heat resistance test, a high temperature and high humidity test, and a heat cycle test. At the same time, the sound absorption property is maintained, so that it can withstand use in various environments.

When the non-woven fabric of the present invention is used as a sound absorbing material, the content of the water-repellent pulp in the non-woven fabric is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably, from the viewpoint of obtaining high sound absorbing properties. Is 70% by mass or more, more preferably 80% by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less, from the viewpoint of setting the content of the heat-sealing adhesive in an appropriate range. is there.

As the sound absorbing material, the non-woven fabric may be used as it is, but it is preferable to have a resin layer on at least one surface of the non-woven fabric. Examples of the resin layer include a surface layer and a rubber layer as described in JP-A-2016-71376, and may be a film layer.
In the present invention, it is preferable that the layer other than the non-woven fabric of the present invention also has water repellency from the viewpoint that it is preferable that the sound absorbing material also has water repellency.

In one preferred embodiment, the water-repellent sound absorbing material of the present invention has long-term water-repellent durability under harsh conditions such as high temperature and humidity. Further, since the sound absorbing material of the present invention is also excellent in sound absorbing property, it can be used for a small device. Therefore, it is more preferable to use it as a sound absorbing material for electrical products that cannot be easily replaced, and devices such as compressors and heat exchangers that generate drainage or dew condensation due to temperature changes, and conditions with high humidity at all times. It is more preferable to use it as a sound absorbing member of the equipment used in the above.

[Oil adsorbent]
The non-woven fabric of the present invention is also preferably used as an oil adsorbent. The oil adsorbent is also called an oil adsorbent.
Here, it is preferable that the oil adsorbent has a higher oil adsorbability than the water adsorbability and selectively adsorbs oil. The oil adsorbent is used for the treatment of kitchen waste liquid in restaurants, oil / water separation tanks, oil spill accidents, construction sites, etc., and is required to have selectivity for oil adsorption, absorption rate, ease of disposal, and the like.
Conventionally, an adsorption mat made of polypropylene or the like has been used as the oil adsorbent. However, sufficient oil adsorptivity could not be obtained with such an oil adsorbent.
The non-woven fabric of the present invention has high water repellency, has high adsorptivity to oil as compared with water adsorbability, and can selectively adsorb oil. Further, since it is manufactured using water-repellent pulp, it has high oil adsorptivity and a high absorption rate can be obtained. Furthermore, since pulp is used, it can be incinerated even after use and does not become industrial waste.

When the non-woven fabric of the present invention is used as an oil adsorbent, the content of water-repellent pulp in the non-woven fabric is preferably 50% by mass or more, more preferably 60% by mass or more, from the viewpoint of obtaining high oil adsorption. It is more preferably 70% by mass or more, still more preferably 80% by mass or more, and preferably 95% by mass or less, more preferably 90% by mass, from the viewpoint of setting the content of the heat-sealing adhesive in an appropriate range. It is as follows. An oil adsorbent using a non-woven fabric containing a large amount of pulp is preferable from the viewpoint of easy disposal after adsorbing the oil.

When the non-woven fabric of the present invention is used as an oil adsorbent, it is preferable to further provide another layer on at least one surface of the non-woven fabric from the viewpoint of obtaining an effect of preventing demineralization. The other layer is also referred to as a skin layer, and is not particularly limited as long as it does not have water absorption, and PP spunbond, PET spunlace, or melt blow is preferable.

The oil that can be adsorbed by the oil adsorbent of the present invention is preferably an oil having a viscosity of 10 to 500 cps. Specific examples thereof include cooking oils such as salad oil and sesame oil, heavy oils, industrial lubricating oils, and gear oils.

The oil adsorbent of the present invention has a structure that does not fall apart when absorbing liquid, and also has an advantage that it can be easily recovered. In addition, the oil adsorbent of the present invention is also preferable in that it does not easily sink into water even after absorbing liquid.
The water-repellent pulp used for the non-woven fabric constituting the oil-adsorbing material of the present invention may be used alone as an oil-adsorbing material, or the water-repellent pulp may be processed into a sheet shape, a tube shape, or the like. You may. Further, the water-repellent pulp may be packed in a bag and used as an oil adsorbent.

[Other uses]
The non-woven fabric of the present invention is not limited to applications used as a sound absorbing material and an oil adsorbent, but is not limited to the medical field, the pharmaceutical field, the beauty field, the hygiene field, the food / cooking field, the automobile field, the electric / electrical field, and the electronic field. , Agricultural field, etc., can be used as a non-woven fabric used for each product such as a breathable cover, a breathable separator, an automobile interior, an air conditioner, and a vacuum cleaner.

The features of the present invention will be described in more detail with reference to Examples and Comparative Examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention should not be construed as limited by the specific examples shown below.

<Measuring method of average fiber diameter and average fiber length>
The average fiber diameter and average fiber length of the fibers described later were measured by the following methods.
In the case of synthetic fibers, the average fiber diameter was measured by referring to the manufacturer's standard value (test value) or by microscopic observation. In the case of pulp fibers, the average fiber diameter was measured by the result of image analysis by a fiber length measuring device (for example, KAJAANI Fiber Lab.).
In the case of synthetic fibers, the average fiber length was measured by microscopic observation. In the case of pulp fibers, the fiber length was measured by a fiber length measuring device (for example, KAJAANI Fiber Lab.) And microscopic observation.

<Preparation of water repellent pulp>
Hardwood pulp sheets were defibrated to prepare defibrated pulp. The obtained defibrated pulp is impregnated with a water repellent (a water repellent containing a maleized petroleum resin alkali salt and liquid paraffin as a main component) to impart water repellency, and after undergoing a drying treatment, the pulp and water repellency are obtained. A water-repellent pulp having enhanced binding of the agent was obtained. The average fiber diameter of the obtained water-repellent pulp was 20 μm, and the average fiber length was 1.5 mm.

As a comparative example, the following pulp fibers were used.
-Coniferous bleached kraft pulp (NBKP): average fiber diameter 50 μm, average fiber length 4 mm

[Water repellency test]
<Settling start time>
The sedimentation start time was measured according to the water absorption test (sedimentation method) specified in JIS L1907: 2010 standard. Specifically, 1,000 mg each of water-repellent pulp and NBKP is floated in water in a water tank (20 × 20 cm) containing water at 20 ° C. ± 2 ° C., and the time until the sample becomes wet and begins to settle ( Settling start time) was measured.

<Pulp water retention in water retention test>
An acrylic bottom surface with an inner diameter that fits snugly was installed in an acrylic frame (hollow square columnar) with a length and width of 10 cm and a height of 6 cm. The degree of adhesion of the bottom surface was set so that even if water was put into the frame on which the bottom surface was installed, the water would seep out slightly.
Separately, weighed filter paper (filter paper sufficient to absorb 40 cc of water) is laid under the frame with the bottom surface, 2 g of pulp fiber is uniformly put in this frame, and 40 cc of water is added to the whole. After 1 minute, an acrylic weight 700 gf having almost the same size as the inner diameter of the frame was placed, and the pulp fibers were gently loaded. After 1 minute, the mass of the filter paper under the frame was measured, the amount of water exuding from the frame was measured, and the difference from the added water of 40 g was taken as the pulp water retention amount (g). That is, the amount of pulp water retained is represented by the following formula (a).
Pulp water retention (g) = 40 (g) -Amount of exuded water (g)
The amount of exuded water was measured from the difference between the mass of the filter paper measured before the test and the mass of the water-absorbed filter paper after the test.
The amount of water retained (blank) when no pulp fiber was added was 0.6 g.

<Liquid flow test>
An acrylic cylinder with an inner diameter of 3 cm and five drainage ports with a hole diameter of 3 mm on the bottom surface was placed on the wire mesh, and 1 g of pulp fiber was compressed to a ^{height of 4 cm (density 0.035 g / cm 3).} After that, 50 cc of water was added at one time, and the amount of discharged water (g) was measured to obtain the amount of liquid flow (g).

<Swelling rate when water is dropped under a microscope>
3-5 mg of pulp fiber was placed on the preparation and about 0.1 ml of water was added with a dropper. After leaving it for about 5 minutes, the preparation was tilted, and the water not absorbed by the pulp fibers was further removed by Kimwipes or the like. The fiber diameter of the pulp fiber was measured from the micrographs before and after the dropping of water, and the swelling rate was calculated by the following formula.
Swelling rate = {fiber diameter (width dimension) of pulp fiber after dropping water-fiber diameter (width dimension) of pulp fiber before dropping water} ÷ fiber diameter (width dimension) of pulp fiber before dropping water (width dimension) x 100 (% )

<Water absorption in tea bag test>
Put pulp fibers in a tea bag (9.5 cm x 7 cm, non-woven fabric using polyester as the main fiber material) (Tokiwa Tea Bag M, manufactured by Tokiwa Kogyo Co., Ltd.) so that the total weight is about 5 g. A weight (500 g) was tied to the tip with a string. The mass of the pulp fiber before the test was calculated by subtracting the empty tea bag mass from the total mass. A tea bag with a weight was placed in a beaker filled with water. Water was added to a height where the entire tea bag was completely submerged. After immersing the tea bag for 5 minutes, it was taken out of the water and hung in the air for 5 minutes to drain the water. The mass of the tea bag (containing pulp fiber) after draining was measured, and the amount of water absorption was calculated by the following formula.
Water absorption (g / g) = (mass of tea bag containing pulp fiber after draining-mass of tea bag containing pulp fiber before immersion in water) ÷ mass of pulp fiber before test The mass of empty tea bag is 0. It was 42 g.
The results of the water repellency test of the fibers used in Examples and Comparative Examples are shown in the table below.

[Example 1]
<Making non-woven fabric>
The water-repellent pulp and the heat-sealing fiber (polyethylene terephthalate composite fiber) are added to the air-laid web forming machine in a mass ratio (repellent) while delivering PET spunbond on a mesh-like endless belt mounted on a conveyor. Water pulp: heat-sealing fibers = 1: 1-3: 1), ^{supplied so that the basis weight is 450 g / m 2} , mixed evenly in the air, along with the intake flow on the mesh-shaped endless belt. By lowering and dropping and depositing, a web was formed on the PET spunbond to obtain an air-laid web.
Next, PET spunbond was further laminated on the air-laid web, passed through a box-type dryer (hot air circulation conveyor oven) capable of allowing hot air to penetrate the web, and treated with hot air to obtain a non-woven fabric. The hot air treatment temperature (hot air circulation conveyor oven temperature) was 160 ° C. to obtain a non-woven fabric.
The total basis weight, thickness and density of the obtained non-woven fabric were measured. The results are shown in Table 2.

[Comparative Examples 1 to 3]
Comparative Example 1: A non-woven fabric in which a water-repellent (fluorine-based) spray is applied to a non-woven fabric (felt) using only synthetic fibers (type: PET).
Comparative Example 2: Non-woven fabric produced by using NBKP instead of water-repellent pulp (without post-processing).
Comparative Example 3: A non-woven fabric obtained by spraying the non-woven fabric of Comparative Example 2 with a water repellent (fluorine-based).

<Krem water absorption>
The water absorption of Krem was measured for the obtained non-woven fabric in accordance with JIS P8141: 2004. The results are shown in Table 2 below. The Krem water absorption was evaluated according to the following evaluation criteria.
-Evaluation criteria-
3: A sheet that hardly absorbs water. Specifically, the Krem water absorption is 0 mm or more and less than 15 mm.
2: A sheet that sucks up with capillary force. Specifically, the Krem water absorption is 15 mm or more and less than 50 mm.
1: Water absorption sheet. Specifically, the Krem water absorption is 50 mm or more.

<Krem water absorption after cleaning treatment>
The obtained non-woven fabric was washed with tap water at 30 ° C. for 1 hour, and then the Krem water absorption was measured in the same manner.

<Krem water absorption after heat resistance test>
The obtained non-woven fabric was subjected to a heat resistance test in which it was exposed to an environment of 100 ° C. for 1000 hours, and then the Krem water absorption was measured in the same manner.

<Krem water absorption after high temperature and high humidity test>
The obtained non-woven fabric was subjected to a high-temperature and high-humidity test in which it was exposed to an environment of 85 ° C. and 95% RH for 600 hours, and then the Krem water absorption was measured in the same manner.

<Krem water absorption after heat cycle test>
The obtained non-woven fabric was subjected to a heat cycle test in which 1 hour at −10 ° C. and 1 hour at 60 ° C. were repeated for 30 cycles, and then the Krem water absorption was measured in the same manner.

Each of the heat resistance test, the high temperature and high humidity test, and the heat cycle test was performed on the non-woven fabric of Example 1, and as a result of similarly measuring the Krem water absorption of the non-woven fabric after the test, the non-woven fabric after any of the tests was obtained. However, the Krem water absorption was 0 mm, and the evaluation was 3.
As described above, it has been shown that the nonwoven fabric of the present invention has high water repellency and can provide a nonwoven fabric having excellent water repellency even under harsh conditions such as high temperature and humidity.

<Measurement of vertical incident sound absorption coefficient>
Using the measurement sample of sound absorption coefficient prepared from each non-woven fabric, the vertical incident sound absorption coefficient was measured in accordance with JIS A 1405-2: 2007 (ISO 10534-2, ASTM E1050). Since the sound absorption coefficient of the material changes depending on the angle at which the sound is incident, the value of the sound absorption coefficient differs depending on the measurement method. The sound absorption coefficient measured under the condition that sound is vertically incident on the material using an acoustic tube is called "vertical incident sound absorption coefficient". "Vertical incident sound absorption coefficient" is used for developing sound absorbing materials and grasping their characteristics.
The vertical incident sound absorption coefficient was measured at frequencies of 1,000 Hz, 1,250 Hz, 1,600 Hz, 2,000 Hz, 2,500 Hz, 3,150 Hz, 4,000 Hz, 5,000 Hz, and 6,300 Hz, respectively. .. The vertical incident sound absorption coefficient at each frequency obtained is shown in FIG.
In addition, the evaluation was performed according to the following evaluation criteria.
3: 1,000 to 6,300 Hz average value is 35% or more, 2,500 to 6,300 Hz average value is 60% or more, and 6,300 Hz is 70% or more 2: Non-woven fabric that does not satisfy the above evaluation 3. Among them, 1,000 to 6,300 Hz average value is 25% or more, 2,500 to 6,300 Hz average value is 35% or more, and 6,300 Hz is 50% or more 1: The above evaluation 3 or evaluation Does not correspond to 2

Comparative Example 3 showed the same sound absorption property as that of Comparative Example 2.

<Sound absorption after endurance test>
The obtained non-woven fabric was subjected to a heat resistance test, a high temperature and high humidity test, and a heat cycle test, and the sound absorption coefficient of the tested non-woven fabric was measured in the same manner as described above. For each of the non-woven fabrics, the same excellent sound absorption coefficient as before the test was obtained.

[Oil absorption / water absorption test]
1. 1. Drop test A 3 cm square of the non-woven fabric (thickness 5 mm) obtained in Example 1 and the softwood pulp non-woven fabric (thickness 5 mm) obtained in Comparative Example 2 above was used as a sample. Place these on a chalet (Fig. 2 (A)), water (Fig. 2 (B)) and salad oil (Nissin salad oil (edible blended oil: edible soybean oil, edible rapeseed oil), manufactured by Nissin Oillio Group Co., Ltd., 23 A viscosity of 65 mpa · s) (FIG. 2 (C)) was added dropwise to the surface at 1.5 ° C. The results are shown in FIG.

In FIG. 2, (a) is the softwood pulp non-woven fabric obtained in Comparative Example 2, and (b) is the non-woven fabric obtained in Example 1.
As shown in FIG. 2A, each non-woven fabric (3 cm square) was placed on a petri dish. As shown in FIG. 2 (B), when 1.5 ml of water was dropped onto each non-woven fabric with a dropper, the softwood pulp non-woven fabric obtained in Comparative Example 2 ((a) in FIG. 2 (B)). Then, water absorption was observed. On the other hand, the non-woven fabric produced using the water-repellent pulp obtained in Example 1 ((b) in FIG. 2 (B)) showed water repellency, and the water became beaded on the surface of the non-woven fabric.
Similarly, when 1.5 ml of oil was dropped onto each non-woven fabric with a dropper, both samples showed oil absorbency ((a) and (b) in FIGS. 2 (C)).
As shown in the results, the non-woven fabric of the present invention did not absorb water and became beaded on the surface. On the other hand, the non-woven fabric (comparative example) prepared by using NBKP instead of water-repellent pulp absorbed water. The cooking oil absorbed both the non-woven fabric of the present invention and the non-woven fabric produced using NBKP.

2. Absorption test with water / oil mixture Above 1. Sample was used. 40 ml of water was put into a petri dish having an inner diameter of φ90 mm, and 4 ml of cooking oil was added thereto to prepare a mixed solution. Each sample was placed on the surface of the mixture and absorbed for about 10 seconds. In the non-woven fabric of the present invention, most of the oil was absorbed and only water remained. The softwood pulp non-woven fabric absorbed both water and oil, leaving a large amount of oil.

3. 3. Oil absorption / water absorption test Air-laid nonwoven fabrics A to C were prepared using water-repellent pulp in the same manner as in Example 1.
The obtained nonwoven fabrics A to C were subjected to an oil absorption / water absorption test by the following methods. The obtained non-woven fabric 5 cm square (0.0025 m ² ) was mixed with salad oil (Nissin salad oil (edible blended oil: edible soybean oil, edible rapeseed oil), manufactured by Nissin Oillio Group Co., Ltd., and had a viscosity of 65 mPa · s at 23.5 ° C. ) Or soaked in an aluminum pad containing water for 5 minutes. Then, the non-woven fabric was taken out on a wire mesh, oil or water was drained for 1 minute, and the mass of each was measured. The results are shown in Tables 4 and 5.

As shown in the results of Tables 4 and 5, in the oil absorption test, 10 to 13 g of oil was absorbed. The oil began to be rapidly absorbed into the non-woven fabric immediately after immersion, and was absorbed by the entire non-woven fabric in about 1 minute after immersion. In the water absorption test, the amount of water absorption was 0.3 to 0.4 g, but this was attached to the surface of the non-woven fabric and did not penetrate into the non-woven fabric.

Next, a 5 cm square (0.0025 m ² ) of the non-woven fabric A is suspended in an aluminum pad containing water in which salad oil is suspended so as to be 5% by mass, and the suspended oil is suspended on the surface of the water. On the other hand, after shaking the liquid or the vat and bringing it into sufficient contact, the non-woven fabric was taken out and the mass was measured. Nonwoven fabric was added until there was no floating oil floating on the surface of the water. The thickness and mass of the second non-woven fabric added are as shown in Table 6. The results are shown in Table 6.

As shown in the results in Table 6, in this test, the floating oil added by the two non-woven fabrics could be adsorbed. Further, it was confirmed that when the non-woven fabric was suspended, the oil was adsorbed on the end face of the non-woven fabric sheet, and then only the oil was selectively sucked into the sheet. The total amount of liquid absorbed by the two non-woven fabrics was 14.4 g, which was almost the same as the amount of oil added to the pad. That is, it was confirmed that the non-woven fabric of the present invention selectively absorbs oil. In addition, the amount of adsorption was also high. Here, the adsorbed amount is an index of the oil adsorption test data, and the adsorbed material of the oil is usually 6 g / g or more or 0.8 / cm ^{3 or more as the adsorbed amount.} For example, it can be said that it has a sufficient effect (oil adsorbent (matte) performance test standard: type approval standard, see Notification No. 52 of the Ship Bureau, Ministry of Transport).
The non-woven fabric of the present invention used in the oil absorption test did not shed paper powder from the sample and had a high absorption rate. Oil absorption started immediately after immersion, and the entire sheet was absorbed within about 1 minute.

The non-woven fabric of the present invention has high water repellency, and further, high water repellency is maintained even under harsh conditions such as high temperature and humidity. Further, the non-woven fabric of the present invention is suitably used as a sound absorbing material, has high sound absorbing property, and has high sound absorbing property even after a durability test. Furthermore, the non-woven fabric of the present invention is also suitably used as an oil adsorbent, and has been shown to have high selectivity for oil. The non-woven fabric of the present invention is expected to be applied to various applications as a non-woven fabric having water repellency, and is particularly useful as a sound absorbing material that absorbs noise and vibration and an oil adsorbent.

Claims (13)

A non-woven fabric containing water-repellent pulp and a heat-sealing adhesive.
A non-woven fabric in which the water-repellent pulp satisfies the following (1).
(1) In the water absorption test specified in JIS L1907: 2010 standard, the settling start time is 30 seconds or more. The nonwoven fabric according to claim 1, wherein the water-repellent pulp further satisfies at least one of the following (2) to (5).
(2) The amount of pulp water retained in the water retention test is 15 g or less (3) The amount of liquid flow in the liquid flow test is 35 g or more (4) The swelling rate when water is dropped under a microscope is 20%. (5) The amount of water absorbed in the tea bag test is 10 (g / g) or less. The non-woven fabric according to claim 1 or 2, wherein the non-woven fabric is a dry non-woven fabric. The non-woven fabric according to any one of claims 1 to 3, wherein the Krem water absorption degree measured in accordance with JIS P8141: 2004 is less than 30 mm. The non-woven fabric according to any one of claims 1 to 4, wherein the non-woven fabric is subjected to a washing treatment in which the non-woven fabric is washed with running water for 1 hour, and then the Krem water absorption degree measured in accordance with JIS P8141: 2004 is less than 30 mm. According to any one of claims 1 to 5, the non-woven fabric is subjected to a heat resistance test in which it is exposed to an environment of 100 ° C. for 1000 hours, and then the Krem water absorption measured in accordance with JIS P8141: 2004 is less than 30 mm. The non-woven fabric described. A claim that the non-woven fabric is subjected to a high-temperature and high-humidity test in which it is exposed to an environment of 85 ° C. and 95% RH for 600 hours, and then the Krem water absorption measured in accordance with JIS P8141: 2004 is less than 30 mm. The non-woven fabric according to any one of 1 to 6. Using the non-woven fabric, 1 hour at -10 ° C and 1 hour at 60 ° C are defined as one cycle, which is subjected to a heat cycle test in which 30 cycles are repeated, and then the Krem is measured according to JIS P8141: 2004. The non-woven fabric according to any one of claims 1 to 7, wherein the water absorption degree is less than 30 mm. A sound absorbing material comprising the non-woven fabric according to any one of claims 1 to 8. The sound absorbing material according to claim 9, wherein the content of the water-repellent pulp in the non-woven fabric is 50% by mass or more. The sound absorbing material according to claim 9 or 10, which has a resin layer on at least one surface of the non-woven fabric. An oil adsorbent comprising the nonwoven fabric according to any one of claims 1 to 8. The oil adsorbent according to claim 12, wherein the content of the water-repellent pulp in the non-woven fabric is 50% by mass or more.

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