JP6778308B2 - Hydrophilic bulky non-woven fabric - Google Patents

Description

The present invention relates to a hydrophilic bulky non-woven fabric that absorbs urine, body fluids, etc. without stagnation, particularly when used as a surface material such as a sanitary material.

In recent years, the spread of disposable diapers has been remarkable, and the required quality and performance have been improved. The non-woven fabric used as the top sheet of a diaper is required to have the ability (water permeability) to pass through the body fluid and quickly transfer the passed body fluid to the absorber. A material generally used as a material for a top sheet that requires water permeability is a hydrophobic polyolefin-based non-woven fabric, and water permeability is imparted by applying a surfactant as a water permeability agent.

So far, for the improvement of water permeability, for example, in the following Patent Document 1, many methods for improving the water permeability have been adopted to improve the water permeability. Improving water permeability means that a surfactant with higher activity must be selected. Therefore, when used as a surface material for sanitary materials, it tends to cause irritation and rash on the skin surface that comes into contact with the skin. It is not preferable from the viewpoint of irritation to.

On the other hand, in Patent Document 2 below, the non-woven fabric is subjected to a shaping process to make the structure of the non-woven fabric surface uneven, thereby reducing the contact area with the skin and the wet return performance and durable water permeability which are indicators of water permeability. The performance is improved. However, in order to impart an uneven structure, processing by special embossing or the like is required, so that the manufacturing cost is high and the productivity is not high. In addition, a portion where the thickness is reduced by molding through the rolls is generated, and the obtained effect of improving the water permeability is not dramatic.

Further, in Patent Document 3 below, the non-woven fabric is subjected to uneven processing to improve the drawing of body fluid. However, this method may give the skin a moist feel. When a flat-shaped non-woven fabric is used as a surface sheet for diapers, sanitary napkins, etc., the entire surface of the non-woven fabric comes into contact with a mixture of pulp and a polymer absorber, which are absorbers located under the surface sheet. When wearing diapers and sanitary napkins, the weight of the user is applied to the surface sheet and absorber, and the non-woven fabric, which is the surface sheet, comes into close contact with the absorber, so that the body fluid adhering to the surface of the non-woven fabric quickly shifts to the absorber. However, when a non-woven fabric having an uneven shape as in Patent Document 3 and having a hollow inside of the convex portion is used as the surface sheet, the convex portion of the non-woven fabric and the absorber are not in contact with each other. Therefore, when the body fluid adheres to the surface of the non-woven fabric, it is difficult for the body fluid to quickly transfer to the absorber. Furthermore, since the body fluid adhering to the convex portion remains retained inside the non-woven fabric due to surface tension, it may give the skin a moist feel. Further, when urinating, if the non-woven fabric has a flat shape, the urine is treated on the entire surface of the non-woven fabric, but if the non-woven fabric has an uneven shape, the urine concentrates in the recesses where it easily flows. That is, the amount of urine flowing in the concave portion is larger than that in the convex portion, and the water permeable agent adhering to the concave portion is washed away by the urine. If the permeable agent in the recess is washed away by the urine, the urine stays in the recess and can give the wearer a damp feel. In addition, there is a concern that the urine remaining in the recesses may evaporate over time, causing a rash or rash on the skin surface.

Japanese Unexamined Patent Publication No. 10-53955 Japanese Unexamined Patent Publication No. 2004-113489 International Publication No. 2012-0873030

In view of the above, an object to be solved by the present invention is to provide a hydrophilic bulky nonwoven fabric having excellent water permeability and suitable as a surface material for sanitary materials such as diaper top sheets.

As described above, in order to exhibit excellent water permeability, the design of the surfactant to be applied as the water permeability and the surface structure of the non-woven fabric are important. In particular, by making the surface of the non-woven fabric a rough structure with fine irregularities, when body fluids such as urine and sweat adhere to the surface of the non-woven fabric, the rougher the surface structure, the lower the contact angle between the body fluid and the surface of the non-woven fabric, and the body fluids. Is easily drawn into the non-woven fabric. The present inventors focused on the fine structure of the surface of the non-woven fabric, diligently studied the number of crimps of the fibers of the long-fiber non-woven fabric, the bonding method, and the method of imparting water permeability, and repeated experiments. As a result, the non-woven fabric in which the fibers were arranged in an appropriate range By developing the above, we succeeded in improving the water permeability 45 degree gradient flow length value and the durable water permeability index, which are indicators of water permeability, and completed the present invention.

That is, the present invention is as follows.
[1] A hydrophilic bulky non-woven fabric made of thermoplastic long fibers having a number of crimps of 5 to 45 / 2.54 cm (inch), and in the X direction when the measurement reference length on the surface of the non-woven fabric is 100 μm. The ratio of the compartment in which the maximum height in the unit compartment defined by the Y direction is 30% or more with respect to the height (thickness) of the non-woven fabric when no load is applied in the Z direction corresponds to the non-woven fabric surface area of 20 mm × 20 mm. The hydrophilic bulky nonwoven fabric having a nonwoven fabric surface structure of 50% or more per 40,000 compartments and containing or being coated with a water permeable agent . [2] The hydrophilic bulky nonwoven fabric according to the above [1], wherein the orientation index of the hydrophilic bulky nonwoven fabric in the thickness direction by X-ray CT is 0.43 or less.
[3] The hydrophilic bulky nonwoven fabric according to the above [1] or [2], wherein the compressive work of the hydrophilic bulky nonwoven fabric is 0.20 gf · cm / cm ² or more and 1.00 gf · cm / cm ² or less.
[4] The hydrophilic bulky nonwoven fabric according to any one of [1] to [3] above, wherein the thermoplastic fiber is a side-by-side type or eccentric sheath-core type composite fiber.
[5] The hydrophilic bulky nonwoven fabric according to any one of [1] to [4] above, wherein the thermoplastic fiber is a polyolefin fiber.
[6] At least one surfactant selected from the group consisting of a higher alcohol, a higher fatty acid, a nonionic surfactant to which ethylene oxide is added, an alkyl phosphate salt, and an anionic activator. The hydrophilic bulky non-woven fabric according to any one of the above [1] to [5].
[7] The water-permeable agent is at least one surfactant selected from the group consisting of a polyether compound, a polyethylene ether-modified silicone, a polyether-modified silicone, a polyester compound, a polyamide compound, and a polyglycerin compound. The hydrophilic bulky non-woven fabric according to any one of [1] to [5].
[8] The hydrophilic bulky nonwoven fabric according to any one of [4] to [7] above, wherein the intersections of the composite fibers are melted and adhered to each other.
[9] The hydrophilic bulky nonwoven fabric according to any one of [1] to [8] above, which is partially thermocompression bonded.
[ 10 ] A sanitary material using the hydrophilic bulky non-woven fabric according to any one of [1] to [ 9 ] above.

Since the hydrophilic bulky non-woven fabric of the present invention has excellent water permeability, it can be suitably used as a top sheet for the surface of sanitary materials such as sanitary napkins, incontinence pads, disposable diapers, etc. It can also be used for masks, cairo, tape base cloths, patch base cloths, emergency bond base cloths, packaging materials, wipe products, medical gowns, bandages, clothing, skin care sheets, and the like.

It is a drawing for demonstrating the measurement of the maximum height (μm) in a unit section on the surface of a non-woven fabric.

Hereinafter, embodiments of the present invention will be described in detail.
The non-woven fabric of the present embodiment is made of a thermoplastic fiber, and may be a long-fiber non-woven fabric manufactured by the spunbond method or a short-fiber non-woven fabric manufactured by the card method or the like. However, in the case of short fiber non-woven fabric, the fibers are aligned in the X or Y direction during carding, and the surface tends to be smooth, and the web is used from the viewpoints of strength, productivity, and reduction of irritation to the skin. As the constituent fibers, long fibers produced by the spunbond method are preferable. In the specification of the present application, long fibers are said to have a fiber length of 55 mm or more. The shorter the fiber length, the more likely it is that the end portion of the fiber will come into contact with the skin. Therefore, the fiber length is preferably 55 mm or more because it gives a prickly feel.

Examples of the thermoplastic resin constituting the thermoplastic fiber include polyolefin resins such as polyethylene, polypropylene and copolymerized polypropylene, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate and copolymerized polyester, and nylon-6. , Nylon-66, polyamide resins such as copolymerized nylon, and biodegradable resins such as polylactic acid, polybutylene succinate, and polyethylene succinate, and are not particularly limited. Polyolefin-based resins are preferable from the viewpoint of the texture of the non-woven fabric and the convenience of recovery because most of the uses are disposable materials.

As the form of the thermoplastic fiber, it is preferable that the fiber is crimped from the viewpoint of imparting characteristics to the surface structure of the non-woven fabric. The number of crimps is preferably 5 pieces / 2.54 cm (inch) or more, more preferably 5 pieces / inch or more and 45 pieces / inch or less, still more preferably 10 pieces / inch or more and 40 pieces / inch or less, and particularly preferably 10. Pieces / inch or more and 25 pieces / inch or less. In a non-woven fabric composed of fibers having a number of crimps of more than 45 fibers / inch, shrinkage and spots due to the crimping of the fibers are conspicuous, the appearance of the non-woven fabric is deteriorated, and the wettback index is deteriorated due to the spots. In addition, a non-woven fabric composed of fibers having a number of crimps of less than 5 fibers / inch cannot obtain the desired surface roughness, and the thickness becomes thin, the texture is impaired, and the desired water permeability is difficult to obtain. Become.

As a means for imparting crimp to the fiber, crimp can be imparted by forming the fiber cross section into a deformed cross-sectional shape and unevenly cooling the fiber during spinning cooling. In addition, it is possible to develop crimping even with a composite fiber composed of two or more types of thermoplastic resins, and the composition is changed to a side-by-side type (S / S), an eccentric sheath core type (eccentric S / C), or the like. By doing so, it is possible to further easily develop crimping. In the case of the eccentric sheath core type (eccentric S / C), the core portion may appear on the fiber surface, and the area ratio of the core portion occupying the fiber surface is preferably 0 to 50%, more preferably 0 to 30. %. When the ratio of the core portion on the fiber surface becomes higher than 50%, it affects the adhesion at the time of joining as a non-woven fabric, and the cloth strength tends to decrease and fluffing tends to occur.

In the case of the eccentric sheath core type (eccentric S / C), the center of gravity of the cross-sectional area of the core portion is preferably deviated by 5 to 40% from the center of gravity of the cross-sectional area of the composite fiber in order to obtain the desired number of crimps. .. The deviation of the core is calculated by the following formula.
Core deviation (%) = (shortest distance between the center of gravity of the cross-sectional area of the composite fiber and the center of gravity of the cross-sectional area of the core) / (thread diameter) x 100

When the fibers are a combination of two or more types of thermoplastic resins, any combination of the above thermoplastic resins is possible as long as the desired effect is achieved, and from the viewpoint of bonding the fibers to each other, the fibers can be combined. A combination of thermoplastic resins having different melting points is preferable. The weight ratio of the resin having the higher melting point difference in the fiber is preferably 20 wt% or more and 80 wt% or less, more preferably 30 wt% or more and 80 wt% or less, and further preferably 50 wt% or more and 70 wt% or less.
From the viewpoint of the texture of the obtained non-woven fabric, it is preferable to use a combination of polyolefin-based resins or a combination of polyolefin-based resin and polyester-based resin. When polyolefin-based resins are used in combination, composite fibers obtained by combining polyethylene, polypropylene, and resins such as copolymers of these monomers and other α-olefins can be mentioned. Other α-olefins have 3 to 10 carbon atoms, and specific examples thereof include propylene, 1-butene, 1-pentene, 1-hexane, 4-methyl-1-pentene, and 1-octene. Be done.

When the polyolefin resin and the polyester resin are combined, it is preferable to use a single component of polyethylene terephthalate or a copolymer containing isophthalic acid or the like as the polyester resin. Further, the polyethylene terephthalate may be modified by blending or the like, or may be provided with an additive or the like.
Among them, polypropylene is used as the first component, and the second component is made of polypropylene because it has strong strength as a combination of thermoplastic resins, is hard to break during use, is excellent in processing suitability during production of sanitary materials, and has a good texture. The component is preferably polyethylene, and when the composite fiber is an eccentric sheath core type, the core portion is preferably the first component and the sheath portion is the second component.

When the fiber is formed of the above two types of thermoplastic resins, the polypropylene of the first component may be a polymer synthesized by a general Chigranata catalyst or a polymer synthesized by a single-site active catalyst typified by metallocene. Good. Further, ethylene random copolymerized polypropylene may be used. These may be one type alone or a combination of two or more types. In particular, it is preferable that the main component is homopolypropylene from the viewpoint of texture, strength and dimensional stability.

Further, from the viewpoint of spinnability in fiber production and the strength of the obtained fiber, the lower limit of the polypropylene MFR is preferably 20 g / 10 minutes or more, more preferably 30 g / 10 minutes or more, and further preferably 40 g / 10 minutes or more. Most preferably, it exceeds 53 g / 10 minutes. The upper limit of MFR is preferably 85 g / 10 minutes or less, more preferably 70 g / 10 minutes or less, and further preferably 60 g / 10 minutes or less. The MFR was measured according to JIS-K7210 "Test method for melt mass flow rate (MFR) and melt volume flow rate (MVR) of plastic-thermoplastic plastic", test temperature 230 ° C., and test load 2.16 kg. ..

When the fiber is formed of the above two types of thermoplastic resins, the polyethylene as the second component may be a polymer synthesized by a general Chigra natta catalyst or a polymer synthesized by a single-site active catalyst typified by metallocene. There may be. The polyethylene is preferably high-density polyethylene or linear low-density polyethylene, and the density is preferably 0.92 to 0.97 g / cm ³ , more preferably 0.925 to 0.96 g / cm ^3. Is.

Further, from the viewpoint of spinnability in the production of fibers, the lower limit of MI of polyethylene is preferably 10 g / 10 minutes or more, and more preferably 15 g / 10 minutes or more. The upper limit of MI is preferably 100 g / 10 minutes or less, more preferably 60 g / 10 minutes or less, and further preferably 40 g / 10 minutes or less. MI was measured according to JIS-K7210 "Test method for melt mass flow rate (MFR) and melt volume flow rate (MVR) of plastic-thermoplastic plastic", test temperature 190 ° C., test load 2.16 kg. ..
When a polyester resin is used, the lower limit of the solution viscosity ηsp / c is preferably 0.2 or more, more preferably 0.6 or more. The upper limit of the solution viscosity ηsp / c is preferably 0.9 or less, more preferably 0.8 or less.

From the viewpoint of strength and productivity, the fibers constituting the non-woven fabric of the present embodiment are preferably in the form of a long-fiber web using the spunbond method. When a composite long fiber is formed by combining two or more types of thermoplastic resins, for example, different thermoplastic resins are melt-extruded from two or more different extruders, and two or more types are used from a spinneret having a large number of spinning holes. The thermoplastic resin of No. 1 is discharged as a thread in a composite state. Next, the discharged yarn is towed by a traction device while being cooled by applying cold air controlled at 5 ° C to 20 ° C. The threads coming out of the traction device are deposited on a conveyor and transported as a web. The webs being transported may be laminated to form a multi-layered non-woven web. In the case of a multi-layer laminated non-woven fabric, each layer may be formed with a different fiber diameter, or a fiber having a special form such as a deformed cross-section yarn, a crimped fiber, or a hollow fiber may be laminated.

For joining the non-woven web, a method of joining using an adhesive, a method of joining with a low melting point fiber or a composite fiber, a method of spraying a hot melt binder during web formation for melt joining, a needle punch, a water flow, etc. A method such as entanglement of fibers can be used in, and is not particularly limited. From the viewpoint of high-speed productivity, the joint may be joined by partial thermocompression bonding. For example, it can be joined through a web between heated embossed / flat rolls that can impart pinpoint, oval, diamond, rectangular or other joint points. The thermocompression bonding area ratio in the partial thermocompression bonding is preferably 5 to 40%, more preferably, from the viewpoints of maintaining strength and flexibility, maintaining the bulk of the non-woven fabric, and preventing the uneven structure of the surface from being crushed between the rolls. Is 5 to 25%.

Further, from the viewpoint of the characteristics of the surface structure of the non-woven fabric and the ease of maintaining the thickness of the non-woven fabric, especially in the case of composite long fibers in which two or more kinds of thermoplastic resins are combined, the intersection points of the fibers are higher than the temperature at which they can be melted and adhered. Any heating method can be used without particular limitation, and the heating method includes a hot air circulation type, a hot air penetration type, an infrared heater type, a method of blowing hot air on both sides of a non-woven fabric, a method of introducing into a heated gas, and the like. , Various heating methods can be used. From the viewpoint that more fiber adhesion points can be obtained at the intersections of the fibers and the breaking strength of the non-woven fabric is increased, heating with hot air is preferable, and hot air penetration type is particularly preferable.

The temperature of the hot air in the hot air penetrating type is preferably adjusted to a temperature suitable for the thermoplastic resin having a low melting point and contributing to bonding among the combined thermoplastic resins. For example, when the resin on the low melting point side of two or more kinds of thermoplastic resins is polyethylene, the preferable temperature of the hot air is 120 to 155 ° C., preferably 135 to 155 ° C., and more preferably 140 ° C. ~ 150 ° C. When the bonding temperature is higher than 120 ° C., the fibers adhere to each other at the intersections of the fibers, and the strength as a non-woven fabric can be exhibited. Further, when the bonding temperature is 155 ° C. or higher, the solubility of the fiber becomes very high and the texture becomes hard.
The wind speed of the hot air is preferably 0.5 to 3.0 m / s, more preferably 0.7 to 2.5 m / s, and even more preferably 2.0 m / s or less. If the wind speed is slow, hot air does not penetrate in the thickness direction of the non-woven fabric, resulting in low strength. Further, when the wind speed is high, hot air penetrates, but the fibers are also crushed at the same time, resulting in a low-volume non-woven fabric.

As long as the surface structure of the non-woven fabric is not adversely affected, the non-woven web before the heat bonding by the hot air may be heat-bonded. From the viewpoint of productivity, the thermal bonding is preferably carried out through a pair of rolls in which a metal embossed roll and a metal flat roll are combined. From the viewpoint of maintaining the shape of the non-woven web and the strength of the finally obtained non-woven fabric, the embossed area ratio is preferably 5 to 30%, more preferably 5 to 20%, still more preferably 6 to 15%. Further, the deeper the embossing depth is, the thicker the non-woven fabric can be maintained, preferably 0.5 to 2.0 mm, and more preferably 0.7 to 1.5 mm. The embossed shape is not particularly limited, but is preferably circular, elliptical, diamond-shaped, or rectangular.

The average fiber diameter of the fibers of the non-woven fabric is preferably 8.0 μm or more and 38.0 μm or less, more preferably 9.0 μm or more and 33.5 μm or less, and further preferably 11.0 μm or more and 26.5 μm or less. From the viewpoint of spinning stability, the average fiber diameter is preferably 8.0 μm or more, and more preferably 38.0 μm or less from the viewpoint of the texture of the non-woven fabric used as a sanitary material.

The basis weight of the non-woven fabric is preferably 8 g / m ² or more and 80 g / m ² or less, more preferably 10 g / m ² or more and 40 g / m ² or less, and further preferably 10 g / m ² or more and 30 g / m ² or less. If the basis weight is 8 g / m ² or more, the strength of the non-woven fabric used for the sanitary material is satisfied, and if the basis weight is 80 g / m ² or less, the texture of the non-woven fabric used for the sanitary material is satisfied and the appearance is excellent. Does not give a thick impression.

The height of the non-woven fabric when no load is applied is preferably 140 μm or more, more preferably 140 μm or more and 3000 μm or less, and further preferably 140 μm or more and 2000 μm or less. From the viewpoint of the texture of the non-woven fabric and the wettability of water permeability, the height when no load is preferably 140 μm or more, and when it exceeds 3000 μm, it gives an appearance thick impression and is rigid and can be used as a sanitary material. Is not suitable.

The orientation index of the non-woven fabric by X-ray CT is 0.43 or less, preferably 0.425 or less. When the orientation index by X-ray CT is in this range, the number of fibers occupying the thickness direction of the non-woven fabric increases, the bulk is not crushed even under load, and the non-woven fabric has bulkiness, and has excellent cushioning property and wettability index. It is possible to obtain a hydrophilic bulky non-woven fabric having a low content. The lower the lower limit, the lower the better, but the orientation index is preferably 0.30 or more, more preferably 0.33 or more.

The compressive work WC of the non-woven fabric of the present embodiment is preferably 0.20 gf · cm / cm ² or more and 1.00 gf · cm / cm ² or less, and more preferably 0.20 gf · cm / cm ² or more and 0. It is 80 gf · cm · cm ² or less, and holding the compression work amount WC in this range can obtain cushioning property as a non-woven fabric used as a sanitary material and an excellent wettback index.

The hydrophilic bulky nonwoven fabric of the present embodiment contains or is coated with a water permeable agent. As the water permeable agent used, a nonionic surfactant to which ethylene oxide such as higher alcohol, higher fatty acid, alkylphenol, etc. is added, an alkyl phosphate salt, etc., in consideration of safety to the human body, safety in the process, etc. Examples thereof include surfactants composed of anionic activators such as alkyl sulfates alone or in admixture. As the water permeable agent, for example, a polyether compound, a polyethylene ether-modified silicone, a polyether-modified silicone, a polyester compound, a polyamide compound, a polyglycerin compound and the like are also preferably used.

As a method of containing or applying a water permeable agent, existing methods such as kneading into fibers, a coating method (gravure coater, kiss coater), and a spraying method can be adopted, such as corona discharge treatment and atmospheric pressure plasma discharge treatment. Pretreatment of may be adopted as needed. As a drying method after coating, a known method using convection heat transfer, conduction heat transfer, radiant heat transfer, or the like can be adopted, and a drying method by hot air or infrared rays, a drying method by heat contact, or the like can be used.

The amount of the water permeable agent adhered varies depending on the intended use, but for example, for sanitary materials, it is usually preferably in the range of 0.10 wt% or more and 1.50 wt% or less, more preferably 0.15 wt% with respect to the non-woven fabric. % Or more and 1.20 wt% or less. If it is less than 0.10 wt%, it is difficult to obtain satisfactory water permeability, while if it exceeds 1.50 wt%, rashes and rashes on the skin are likely to occur.

The water permeable agent may be diluted with a solvent such as water and applied as an aqueous solution. Further, in order to prevent insufficient drying in the drying process due to the speeding up of the equipment, it is preferable that the amount of the aqueous solution of the permeable agent applied is small. The coating amount (wt%) on the non-woven fabric is preferably 1.0 wt% or more and 65 wt% or less, more preferably 3.0 wt% or more and 60 wt% or less, and further preferably 5.0 wt% or more in any of the above coating methods. It is 50 wt% or less. If it is less than 1.0 wt%, uniform coating cannot be obtained, while if it exceeds 65 wt%, the required drying capacity is increased, the equipment cost is increased, and insufficient drying may occur.

For example, in the application of the water permeable agent by the gravure coater, the handle of the gravure roll may be a lattice type or a pyramid type, but a diagonal line type in which the water permeable agent does not easily remain on the cell bottom of the gravure is preferable. The cell volume is preferably 5 cm ³ / m ² or more and 40 cm ³ / m ² or less, and if it is less than 5 cm ³ / m ² , uniform coating becomes difficult because the coating amount is too small, and if it exceeds 40 cm ³ / m ² , it is coated. Since the amount is too large, problems such as insufficient drying in the drying process and uneven adhesion of the water permeable agent due to migration occur.
The depth of the gravure cell is preferably 10 μm or more and 80 μm or less, and the interval thereof is preferably within the range of 80 mesh or more and 250 mesh or less, and it is preferable to design so as to have the cell volume.

It can be applied at high speed of equipment and can be applied efficiently, even thick non-woven fabric can be applied uniformly in the thickness direction, and even if the permeability of the water permeable agent and the non-woven fabric is slightly poor, it can be applied uniformly. Moreover, since there is no step of passing the non-woven fabric between the pair of rolls, it is easy to maintain the thickness of the non-woven fabric, so it is preferable to apply the water permeable agent by the spray method. The spraying method may be a generally known spraying method by air compression or a method of directly compressing and spraying an aqueous solution of a water permeable agent, but a rotor dampening method is particularly preferable from the viewpoint of being able to uniformly apply to a non-woven fabric. .. It is possible to apply even at high speed of the equipment by taking measures to prevent the water permeable agent aqueous solution from scattering during application. The rotor dampening method is a method in which an aqueous solution of a water permeable agent is supplied onto a rotating rotor and the aqueous solution of the water permeable agent is sprayed by using the centrifugal force of the rotation of the rotor. In the rotor dampening method, the openings are limited so that the liquid particles of the water permeable agent aqueous solution, which is blown by the rotation of the rotor in the coating direction, can be sprayed only on the non-woven fabric side to be coated, and can be uniformly applied in the CD direction of the non-woven fabric. , It is possible to adjust the spray particle size by the rotor rotation speed.

In the case of the rotor dampening method, for example, a rotor having a diameter of 40 mm or more and 100 mm or less is selected, and the surface of the non-woven fabric to be applied and the center of the rotor are applied so that the aqueous solution of the permeable agent can be uniformly adhered in the CD direction of the non-woven fabric to be applied. Set the distance of. It is desirable that half of the coating distribution range sprayed from the adjacent rotor overlaps. Further, it is desirable that the rotors are arranged at equal intervals in a range of 60 mm or more and 220 mm or less in the CD direction to have two stages.

The point of uniform application is to spread the spray particles to the inside of the non-woven fabric to be applied, and the spray particle diameter is preferably 0.010 mm or more and 0.200 mm or less, and further 0.030 mm or more and 0.070 mm or less. preferable. The surface tension of the aqueous water permeable agent is important for forming the optimum spray particle size, and the spray particle size is calculated by the following formula.
Spray particle diameter (μm) = {100,000 x √ (surface tension (N / m))} / (rotor diameter (mm) x rotor rotation speed (rpm))

The temperature of the aqueous permeable agent solution in these coating methods is preferably 5 ° C. or higher and 50 ° C. or lower, and more preferably 12 ° C. or higher and 40 ° C. or lower from the viewpoint of uniform dispersion and stability of the solution. The viscosity of the aqueous permeable agent solution is preferably 0.5 mPa · s or more and 50 mPa · s or less, and more preferably 0.8 mPa · s or more and 20 mPa · s or less from the viewpoint of easier uniform application. If the viscosity exceeds 50 mPa · s, the permeability of the aqueous water permeable agent solution to the non-woven fabric is inferior, and uniform coating becomes difficult.

A general drying method can be used for drying after the application of the water permeable agent aqueous solution, and the drying method is not particularly limited, and a known method using convection heat transfer, conduction heat transfer, radiant heat transfer, etc. is adopted. Various drying methods can be used, such as a hot air circulation type, a hot air penetration type, an infrared heater type, a method of blowing hot air on both sides of a non-woven fabric, and a method of introducing into a heated gas.

As shown in FIG. 1, the feature of the surface structure of the non-woven fabric of the present embodiment is that the maximum height in the unit compartment defined by the X-direction and Y-direction when the measurement reference length on the non-woven fabric surface is 100 μm. The ratio of the compartments which is 30% or more with respect to the height (thickness) of the nonwoven fabric when no load is applied is 50% or more per 40,000 compartments corresponding to the surface area of the nonwoven fabric of 20 mm × 20 mm.
The measurement reference length and maximum height on the surface of the non-woven fabric are as follows. Using a digital microscope KH-8700 (manufactured by Hirox), height information on the surface of the non-woven fabric is measured and collected at intervals of 20 μm in each direction at 20 mm in the MD direction and 20 mm in the CD direction. The height information obtained in the MD direction 20 mm × CD direction 20 mm of the non-woven fabric was partitioned every 100 μm, and the partitioned length at this time was used as the measurement reference length. Further, the difference between the maximum value and the minimum value in the unit compartment was defined as the maximum height on the surface of the non-woven fabric. The ratio of the maximum height to the height (thickness) of the non-woven fabric under no load was calculated from the maximum height (μm) / height under no load (μm) × 100.
That is, the higher the ratio of the compartments in which the ratio of the maximum height to the height (thickness) of the non-woven fabric when no load is 30% or more, the larger the difference in unevenness in the fine compartments on the surface of the non-woven fabric. In the present embodiment, the compartment in which the ratio of the maximum height to the height (thickness) of the non-woven fabric when no load is 30% or more is defined as a measurement reference length of 100 μm in the MD direction 20 mm × CD direction 20 mm of the nonwoven fabric. It is 50% or more per 40,000 plots. By having such a structural feature of the non-woven fabric surface, for example, when a liquid such as urine adheres to the non-woven fabric surface regardless of the water permeable agent applied to the non-woven fabric, the contact angle is lowered and the contact angle is lowered from the non-woven fabric surface. Rapidly transfer liquid to the inside of non-woven fabric. From the viewpoint of liquid transferability of the non-woven fabric, in the present embodiment, the ratio of the compartments having the maximum height of 30% or more with respect to the height (thickness) of the non-woven fabric under no load is 50% or more, preferably 50% or more. It is 52% or more, more preferably 55% or more, still more preferably 60% or more. When such a ratio is within the range, good water permeability is exhibited. The higher the ratio, the better, but 98% or less is preferable because the touch is deteriorated.

The water permeability 45 degree gradient flow length value, which is an index of the water permeability of the nonwoven fabric of the present embodiment, is 25 mm or less, preferably 22 mm or less, more preferably 20 mm or less, and most preferably 18 mm or less. When the water permeability 45 degree gradient flow length value exceeds 25 mm, for example, when used for a surface material such as a disposable diaper, the liquid flow on the surface increases and urine leakage is likely to occur.

The fourth durable water permeability index, which is an index of the water permeability of the non-woven fabric of the present embodiment, is 85% or more. If the value of the durability permeability index of the 4th time is less than 85%, for example, when it is used for a surface material such as a disposable diaper, the surface material cannot pass water for multiple urinations and loses its function as a surface material. , Prone to urine leakage.

The wettability index, which is an index of the water permeability of the nonwoven fabric of the present embodiment, is preferably 0.8 g or less, more preferably 0.5 g or less. When the value of the wettability index exceeds 0.8 g, for example, when it is used as a surface material of a disposable diaper, when the surface material comes into contact with the skin, it feels very moist and the feeling of use deteriorates. The lower the wettback index, the better, but a value of 0.01 g or less is the lower limit of measurement, and the measurement variation is large.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. The evaluation method for each characteristic is as follows, and the obtained physical properties are shown in Table 1 below. Hereinafter, the flow direction in the non-woven fabric manufacturing is referred to as the MD direction, and the width direction perpendicular to the MD direction is referred to as the CD direction.

1. 1. Average fiber diameter (μm)
A 1 cm square test piece was taken by dividing the non-woven fabric into 5 equal parts in the CD direction, and the diameters of the fibers were measured at 20 points each with a KEYENCE microscope VHX-700F, and the average value was calculated.

2. Non-woven fabric basis weight (g / m ² )
According to JIS-L1906, 5 test pieces of 20 cm in MD direction x 5 cm in CD direction were collected so that the collection positions were even in the CD direction of the non-woven fabric, the mass was measured, and the average value was calculated as the weight per unit area. It was converted and calculated as a scale (g / m ² ).

3. 3. Height (thickness) (μm) of non-woven fabric when no load is applied
Ten arbitrary test pieces of 4 mm in the MD direction and 10 mm in the CD direction were sampled, and a photograph of the cross section of the non-woven fabric was taken using an SEM (VE-8800) manufactured by KEYENCE. For the obtained image, the distance in the thickness direction was measured at 5 points per image using the same image analysis software manufactured by KEYENCE, and the average value was taken as the height (thickness) (μm) when no load was applied.

4. Maximum height (μm) on the surface of the non-woven fabric
The non-woven fabric is cut and collected in any direction with a square size of 20 mm × 20 mm. Next, using the 3D profile function of the digital microscope KH-8700 (manufactured by Hirox), the height information of the surface of the non-woven fabric is measured and collected at intervals of 20 μm in each direction of 20 mm in each side direction of the square of the non-woven fabric. The height information obtained on each side of the non-woven fabric square of 20 mm × 20 mm was partitioned every 100 μm, and the partitioned length at this time was used as the measurement reference length. Further, the difference between the maximum value and the minimum value in the section was defined as the maximum height on the surface of the non-woven fabric. This measurement procedure is schematically shown in FIG.
The ratio of the maximum height on the surface of the non-woven fabric to the height (thickness) (μm) of the non-woven fabric under no load was calculated by the maximum height (μm) / height (thickness) (μm) with no load × 100.
Further, the number of compartments in which the ratio of the maximum height to the height (thickness) of the non-woven fabric when no load is 30% or more is defined as a measurement reference length of 100 μm in each side direction of 20 mm × 20 mm of the non-woven fabric square. The ratio (%) was calculated by dividing by the number of sections.

5. Orientation index (X-ray CT)
A test piece of 5 mm in the MD direction × 5 mm in the CD direction was arbitrarily cut and measured with a field of view of about 3 mm × 3 mm at the time of image analysis. A high-resolution 3DX ray microscope nano3DX (manufactured by Rigaku Co., Ltd.) was used as a measuring device, and CT measurement was performed using low-energy, high-luminance X-rays capable of obtaining contrast even with light elements. The detailed conditions are shown below.
X-ray target: Cu
X-ray tube voltage: 40 kV
X-ray tube current: 30mA
Lens: 1.08 μm / pix
Binning: 2
Rotation angle: 180 °
Number of projections: 1000 sheets Exposure time: 10 seconds / sheet Number of camera pixels: 3300 x 2500
Reconstruction: The three-dimensional tomogram obtained by the Feldkamp method CT measurement was image-analyzed, and the orientation indexes Ix, Iy, and Iz of the three orthogonal axes (x, y, z) were obtained. The thickness direction of the sample to be evaluated was mainly matched with the z direction. Here, the orientation indexes Ix, Iy, and Iz are the sum of the areas of the fiber surfaces viewed from each of the x, y, and z directions (the sum of the total projected areas of the fiber surfaces in each direction), respectively. , When set to Az
Ix = Ax / (Ax + Ay + Az)
Iy = Ay / (Ax + Ay + Az)
Iz = Az / (Ax + Ay + Az)
Defined in. Ax, Ay, and Az were obtained from the tomogram. In this index, it is oriented in the direction of the smaller value. Moreover, in the isotropic structure, it is all 1/3.

6. Compression work (WC)
Five 5 cm square test pieces were collected in the CD direction and measured using a compression test device (KES-G5) manufactured by Kato Tech. The test piece was placed on a metal sample table and compressed between steel plates having a circular plane with a pressure area of 2 cm ² . The compression rate was 0.067 mm / s, and the maximum compression load was 3.4 kPa (35 gf / cm ² ). The recovery process was also measured at the same speed, and the average value of compression work was calculated.

7. Number of crimps (pieces / 2.54 cm (inch))
Divide the non-woven fabric into 5 equal parts in the CD direction, collect a 5 cm square test piece, select 5 fibers with a Keyence microscope VH-Z450 without applying a load to the fibers, and per 1 inch in length. The number of crimps was measured, and the number of crimps (pieces / inch) was calculated from the average value.

8. Permeability 45 degree gradient flow length value (mm)
Ten sheets of toilet paper (Hard Single 1R55m manufactured by Itoman Corporation) are stacked as an absorber on a board inclined at 45 degrees, and a test cloth (20 cm square) is placed on it and set, and the height is 10 mm above the cloth. 0.1 cc of physiological saline was added dropwise from the water. The distance from the dropping position to the end of absorption was read. This measurement was arbitrarily performed at 20 points in the test cloth, and the average value was taken as the hydraulic conductivity 45 degree gradient flow length value (mm).

9. Endurance permeability index (%)
As an absorber, 10 sheets of toilet paper (Hard Single 1R55m manufactured by Itoman Corporation) are stacked, and a test cloth (20 cm × 30 cm) is placed on the stack. Furthermore, a stainless steel plate with 10 holes with a diameter of 1.5 cm at equal intervals is placed on it, and 0.3 cc of physiological saline is dropped from a height of 10 mm above the cloth located in each hole, and 3 After a lapse of minutes, drop again in the same manner. Count the number of holes (A) absorbed within 10 seconds after the third drop. This was tested at 40 locations of the same sample, and {((A) / (10 holes × 40 samples) × 100)} was defined as the third hydraulic conductivity index (%). In addition, the number of holes (B) absorbed within 10 seconds after the fourth dropping is continuously counted, and {((B) / (10 holes x 40 samples) x 100). } Was set as the 4th water permeability durability index (%).

10. Wetting return index (g)
In order to keep the characteristics of the absorber constant as an absorber, a test cloth is placed on three specific filter papers (GRADE: 989 manufactured by Ahlstrоm). Furthermore, a plate (about 800 g) with a hole of 10 cm square and a diameter of 25 mm in the center is placed on it, and physiological saline (3.5 times the weight of the absorber) is dropped from the height of 25 mm above the center hole. And absorb it. Next, the plate on the test cloth is removed, and a 3.5 kg weight (10 cm square) is gently placed on the test cloth for 3 minutes to stabilize the distribution of the liquid in the absorber. Next, once the 3.5 kg weight is removed, two pre-weighed measuring filter papers (HOLLINGSWORTH & VOSE.CONPANY ERTMWWSSHEETS 12.5 cm square) are quickly placed on the test cloth, and the 3.6 kg weight is gently placed again. .. After 2 minutes, weigh the weight increase of the measuring filter paper. The value (g) of the increase was used as the wettback index.

11. Amount of water permeable aqueous solution applied (wt%)
The value calculated by the following formula from the consumption amount of the water permeable agent aqueous solution for 1 hour of the water permeable processing was taken as the coating amount (wt%) of the water permeable agent aqueous solution.
Coating amount (wt%) = Water permeable agent aqueous solution consumption (g) / {Non-woven fabric grain (g / m ² ) x width (m) x processing speed (m / min) x 60 (min)} x 100

12. Amount of pure water permeable agent adhered (wt%)
Regarding the weight (W1) of the non-woven fabric sample to which the water-permeable agent adjusted at a temperature and humidity of 25 ° C. × 40% RH for 24 hours was attached, the weight of the water-permeable agent (W2) extracted from this non-woven fabric sample by Soxhlet using methanol. Was measured, and the amount of pure water permeable agent attached C (wt%) was calculated from the following formula.
C (wt%) = [W2 / W1] x 100
Sampling of the non-woven fabric sample is performed from 5 places at 30 cm intervals in the MD direction and 5 places at equal intervals within the width of the non-woven fabric in the CD direction so that the cut width is in the range of 5 cm to 10 cm and the non-woven fabric sample is about 2 g. , Collect a total of 10 test cloths. The above measurements were carried out, and the average value thereof was taken as the amount of pure water permeable agent adhered (wt%).

13. The dispersed non-woven fabric was collected at a size of 50 cm × 50 cm and graded according to the following evaluation criteria for the appearance of the non-woven fabric by visual judgment. From the viewpoint of evaluation of dispersion, it was determined whether the spots such as streaks were not regular and whether the single yarns were spread uniformly (whether they were lumpy). The higher the grade, the better the dispersion.
5: Very good 4: Good 3: Normal (level that can be used as a product)
2: Bad 1: Very bad

[Example 1]
Polypropylene (PP) resin with an MFR of 55 g / 10 minutes (measured at a temperature of 230 ° C. and a load of 2.16 kg according to JIS-K7210) is used as the first component, and MI is 26 g / 10 minutes (measured according to JIS-K7210). High-density polyethylene (HDPE) resin (measured at 190 ° C. and a load of 2.16 kg) is used as the second component, and the discharge rate of the first component is 0.4 g / min · hоle, and the discharge rate of the second component is 0.4 g / min. Fibers having a total discharge rate of 0.8 g / min / hоle and a ratio of the first component to the second component being 1/1 are extruded by the spunbond method at a spinning temperature of 220 ° C. to extrude this filament group. An eccentric sheath-core type composite long fiber web having an average fiber diameter of 17.9 μm extruded toward a mobile collection surface was prepared at a spinning speed of 3200 m / min using a high-density airflow traction device using an air jet.
Next, the obtained web was adhered to each other with hot air having a hot air temperature of 142 ° C. and a hot air velocity of 0.7 m / s to obtain a composite long-fiber non-woven fabric having a basis weight of 18 g / m ² and a number of crimps of 15 / inch.
Next, a 3 wt% aqueous solution of a water permeable agent composed of a mixture of hexaglycerin monostearic acid ester, polyether-modified silicone and polyoxyalkylene castor oil ether was applied to the obtained non-woven fabric as a water permeable agent aqueous solution at a liquid temperature of 20 ° C. and a liquid viscosity. The mixture was adjusted to 2 mPa · s and applied to the non-woven fabric by a rotor dampening method so that the coating amount was 10 wt%. The diameter of the rotors used was 80 mm, and each rotor was arranged at intervals of 115 mm in the CD direction and the distance between the center of the rotor and the non-woven fabric to be applied was 180 mm. Further, the rotor rotation speed was adjusted so that the spray particle size of the sprayed aqueous solution of the water permeable agent was 35 μm.
The ratio of the compartment in which the maximum height in the compartment when the measurement reference length on the surface of the obtained non-woven fabric is 100 μm is 30% or more with respect to the height (thickness) of the non-woven fabric under no load is 85%. The water permeability of the non-woven fabric was 45 degrees, the gradient flow length value was 16 mm, the fourth durability water permeability index was 99%, and the wet return index was 0.12 g. The results are shown in Table 1 below.

[Example 2]
An eccentric sheath-core type composite long fiber non-woven fabric having an average fiber diameter of 17.9 μm, a basis weight of 10 g / m ² , and a number of crimps of 15 / inch was obtained by the same method as in Example 1. Next, the same aqueous solution of a water permeable agent as in Example 1 was applied to the obtained composite long fiber non-woven fabric under the same coating conditions.
When the measurement reference length on the surface of the obtained non-woven fabric is 100 μm, the ratio of the compartment in which the maximum height in the compartment is 30% or more with respect to the height (thickness) of the non-woven fabric when no load is applied is 87%. The non-woven fabric had a water permeation of 45 degrees, a gradient flow length value of 14 mm, a fourth endurance water permeation index of 99%, and a wet return index of 0.50 g. The results are shown in Table 1 below.

[Example 3]
The discharge rate of the first component is 0.54 g / min / hоle, the discharge rate of the second component is 0.26 g / min / hоle, and the total discharge rate is 0.80 g / min / hоle, and the first component and the second component. An eccentric sheath-core type composite long fiber web having an average fiber diameter of 17.9 μm was prepared in the same manner as in Example 1 except that the ratio of the components was about 1/2.
The obtained eccentric sheath-core type composite long fiber web is bonded to each other by hot air having a hot air temperature of 145 ° C. and a hot air velocity of 1.0 m / s, and a composite having a grain size of 18 g / m ² and a number of crimps of 10 pieces / inch. A long fiber non-woven fabric was obtained.
Next, the same aqueous solution of a water permeable agent as in Example 1 was applied to the obtained composite long fiber non-woven fabric under the same coating conditions.
The ratio of the compartments in which the maximum height in the compartment when the measurement reference length on the surface of the obtained non-woven fabric is 100 μm is 30% or more with respect to the height (thickness) of the non-woven fabric under no load is 74%. The water permeability of the non-woven fabric was 45 degrees, the gradient flow length value was 16 mm, the fourth durability water permeability index was 99%, and the wet return index was 0.12 g. The results are shown in Table 1 below.

[Example 4]
A composite long-fiber non-woven fabric having an average fiber diameter of 17.9 μm, a basis weight of 18 g / m ² , and a number of crimps of 10 / inch was obtained by the same method as in Example 3.
On the obtained composite long fiber non-woven fabric, a 1 wt% aqueous solution of a water permeable agent is adjusted to a liquid temperature of 20 ° C. and a liquid concentration of 2.3 mPa · s by a gravure coating method, and a diagonal pattern is applied so that the coating amount is 30 wt%. The coating was applied using a gravure roll of 120 mesh and a cell volume of 22 cm ³ / m ² , and then dried and wound by passing through a cylinder dryer at 120 ° C.
The ratio of the compartment in which the maximum height in the compartment when the measurement reference length on the surface of the obtained non-woven fabric is 100 μm is 30% or more with respect to the height (thickness) of the non-woven fabric when no load is applied is 70%. The non-woven fabric had a water permeation of 45 degrees, a gradient flow length value of 17 mm, a fourth endurance water permeation index of 97%, and a wet return index of 0.22 g. The results are shown in Table 1 below.

[Example 5]
The first component is the same polypropylene resin as in Example 1, and the second component is a linear low-density polyethylene with a MI of 16.8 g / 10 minutes (measured at a temperature of 190 ° C. and a load of 2.16 kg according to JIS-K7210). (LLDPE) resin, the discharge rate of the first component is 0.54 g / min · hоle, the discharge rate of the second component is 0.26 g / min · hоle, and the total discharge rate is 0.8 g / min · hоle. A fiber having a ratio of the first component to the second component of about 1/2 is extruded by a spunbond method at a spinning temperature of 220 ° C., and this filament group is directed toward a mobile collection surface using a high-speed airflow traction device using an air jet. To prepare an eccentric sheath-core type long fiber web having an average fiber diameter of 20.5 μm.
The obtained eccentric sheath-core type long fiber web is bonded to each other by hot air having a hot air temperature of 150 ° C. and a hot air speed of 0.3 m / s, and a composite long fiber having a grain size of 18 g / m ² and a number of crimps of 40 / inch. A non-woven fabric was obtained.
Next, the same aqueous solution of a water permeable agent as in Example 1 was applied to the obtained composite long fiber non-woven fabric under the same coating conditions.
The ratio of the compartments in which the maximum height in the compartment when the measurement reference length on the surface of the obtained non-woven fabric is 100 μm is 30% or more with respect to the height (thickness) of the non-woven fabric under no load is 92%. The non-woven fabric had a water permeation of 45 degrees, a gradient flow length value of 15 mm, a fourth endurance water permeation index of 99%, and a wet return index of 0.35 g. The results are shown in Table 1 below.

[Example 6]
An eccentric sheath-core type composite long-fiber non-woven fabric having an average fiber diameter of 20.5 μm, a basis weight of 18 g / m ² , and a number of crimps of 40 / inch was obtained by the same method as in Example 5. Next, the same aqueous solution of the water-permeable agent as in Example 1 was applied to the obtained composite long-fiber non-woven fabric under the same coating conditions, except that the concentration of the aqueous solution of the water-permeable agent was 5 wt%.
The ratio of the compartments in which the maximum height in the compartment when the measurement reference length on the surface of the obtained non-woven fabric is 100 μm is 30% or more with respect to the height (thickness) of the non-woven fabric under no load is 92%. The non-woven fabric had a water permeation of 45 degrees, a gradient flow length value of 13 mm, a fourth durability water permeation index of 99%, and a wet return index of 0.47 g. The results are shown in Table 1 below.

[Example 7]
An eccentric sheath-core type composite long fiber web having an average fiber diameter of 17.9 μm was prepared in the same manner as in Example 1.
Next, the obtained eccentric sheath-core type composite long fiber non-woven fabric was used as a flat roll and an embossed roll at 100 ° C. (pattern specifications: circular diameter 1.00 mm, staggered arrangement, horizontal pitch 4.4 mm, vertical pitch 4.4 mm, The fibers are temporarily bonded to each other by passing them through a pressure-bonding area ratio of 7.9%), and then the fibers are bonded to each other by hot air having a hot air temperature of 142 ° C. and a hot air velocity of 0.7 m / s, with a grain size of 18 g / m ² and winding. A composite long fiber non-woven fabric having a reduced number of 17 pieces / inch was obtained.
Next, the same aqueous solution of a water permeable agent as in Example 1 was applied to the obtained composite long fiber non-woven fabric under the same coating conditions.
The ratio of the compartment in which the maximum height in the compartment when the measurement reference length on the surface of the obtained non-woven fabric is 100 μm is 30% or more with respect to the height (thickness) of the non-woven fabric when no load is applied is 72%. The non-woven fabric had a water permeation 45 degree gradient flow length value of 18 mm, a fourth durable water permeation index of 95%, and a wet return index of 0.18 g. The results are shown in Table 1 below.

[Example 8]
An eccentric sheath-core type composite long fiber non-woven fabric having an average fiber diameter of 17.9 μm, a basis weight of 8 g / m ² , and a number of crimps of 17 / inch was obtained by the same method as in Example 7. Next, the same aqueous solution of a water permeable agent as in Example 1 was applied to the obtained composite long fiber non-woven fabric under the same coating conditions.
The ratio of the compartments in which the maximum height in the compartment when the measurement reference length on the surface of the obtained non-woven fabric is 100 μm is 30% or more with respect to the height (thickness) of the non-woven fabric under no load is 74%. The water permeability of the non-woven fabric was 45 degrees, the gradient flow length value was 16 mm, the fourth durability water permeability index was 97%, and the wet return index was 0.42 g. The results are shown in Table 1 below.

[Example 9]
Using the same components as in Example 1, the discharge rate of the first component is 0.40 g / min · hоle, the discharge rate of the second component is 0.40 g / min · hоle, and the total discharge rate is 0.8 g / min. A fiber having a hоle ratio of 1/1 of the first component and the second component was extruded by a spunbond method at a spinning temperature of 220 ° C. This group of filaments was extruded toward a mobile collection surface at a spinning speed of 3200 m / min using a high-speed airflow traction device using an air jet to prepare a side-by-side composite long fiber web having an average fiber diameter of 17.9 μm.
Next, the obtained side-by-side type composite long fiber web was adhered to each other in the same manner as in Example 7 to obtain a composite long fiber non-woven fabric having a basis weight of 18 g / m ² and a number of crimps of 23 / inch. Next, the same aqueous solution of a water permeable agent as in Example 1 was applied to the obtained composite long fiber non-woven fabric under the same coating conditions.
When the measurement reference length on the surface of the obtained non-woven fabric is 100 μm, the ratio of the compartments in which the maximum height in the section is 30% or more with respect to the height (thickness) of the non-woven fabric in the unloaded state is 76%. The water permeability of the non-woven fabric was 45 degrees, the gradient flow length value was 15 mm, the fourth durability water permeability index was 99%, and the wet return index was 0.15 g. The results are shown in Table 1 below.

[Example 10]
The first component is polyethylene terephthalate (PET) having a solution viscosity of ηsp / c0.75, the second component is high-density polyethylene (HDPE) similar to Example 1, and the discharge rate of the first component is 0.54 g / min. A fiber having a hоle, a discharge rate of 0.26 g / min · hоle of the second component, a total discharge rate of 0.80 g / min · hоle, and a ratio of the first component to the second component of about 1/2. Extruded at a spinning temperature of 295 ° C. by the spunbond method, and extruded this filament group toward the mobile collection surface using a high-speed airflow traction device using an air jet. Eccentric sheath-core type composite long fibers with an average fiber diameter of 18.7 μm. Prepared the web.
The obtained eccentric sheath-core type composite long fiber web was adhered to each other in the same manner as in Example 1 to obtain a composite long fiber non-woven fabric having a basis weight of 18 g / m ² and a number of crimps of 20 / inch.
Next, the same aqueous solution of a water permeable agent as in Example 1 was applied to the obtained composite long fiber non-woven fabric under the same coating conditions.
When the measurement reference length on the surface of the obtained non-woven fabric is 100 μm, the ratio of the compartment in which the maximum height in the compartment is 30% or more with respect to the height (thickness) of the non-woven fabric when no load is applied is 87%. The non-woven fabric had a water permeation of 45 degrees, a gradient flow length value of 15 mm, a fourth endurance water permeation index of 99%, and a wet return index of 0.15 g. The results are shown in Table 1 below.

[Example 11]
Using the same components as in Example 1, the discharge rate of the first component is 0.24 g / min · hоle, the discharge rate of the second component is 0.56 g / min · hоle, and the total discharge rate is 0.8 g / min. An eccentric sheath-core type composite long fiber web having an average fiber diameter of 17.9 μm was prepared in the same manner as in Example 1 except that it was hоle and the ratio of the first component to the second component was 3/7. did.
The obtained eccentric sheath-core type composite long fiber web was adhered to each other in the same manner as in Example 1 to obtain a composite long fiber non-woven fabric having a basis weight of 18 g / m ² and a number of crimps of 17 / inch. Next, the same aqueous solution of a water permeable agent as in Example 4 was applied to the obtained composite long fiber non-woven fabric under the same coating conditions.
When the measurement reference length on the surface of the obtained non-woven fabric is 100 μm, the ratio of the compartments in which the maximum height in the section is 30% or more with respect to the height (thickness) of the non-woven fabric in the unloaded state is 70%. The water permeability of the non-woven fabric was 45 degrees, the gradient flow length value was 18 mm, the fourth durability water permeability index was 95%, and the wet return index was 0.18 g. The results are shown in Table 1 below.

[Example 12]
Using the same components as in Example 1, the discharge rate of the first component is 0.16 g / min · hоle, the discharge rate of the second component is 0.64 g / min · hоle, and the total discharge rate is 0.8 g / min. An eccentric sheath-core type composite long fiber web having an average fiber diameter of 18.7 μm was prepared in the same manner as in Example 1 except that it was hоle and the ratio of the first component to the second component was 1: 4. did.
The obtained eccentric sheath-core type composite long fiber web was adhered to each other in the same manner as in Example 1 to obtain a composite long fiber non-woven fabric having a basis weight of 18 g / m ² and a number of crimps of 5 / inch. Next, the same aqueous solution of a water permeable agent as in Example 1 was applied to the obtained composite long fiber non-woven fabric under the same coating conditions.
When the measurement reference length on the surface of the obtained non-woven fabric is 100 μm, the ratio of the compartments in which the maximum height in the section is 30% or more with respect to the height (thickness) of the non-woven fabric in the unloaded state is 52%. The water permeability of the non-woven fabric was 45 degrees, the gradient flow length value was 22 mm, the fourth durability water permeability index was 85%, and the wet return index was 0.45 g. The results are shown in Table 1 below.

[Example 13]
Using the same components as in Example 1, the discharge rate of the first component is 0.40 g / min · hоle, the discharge rate of the second component is 0.40 g / min · hоle, and the total discharge rate is 0.8 g / min. A fiber having a hоle ratio of a first component to a second component of 1: 1 was extruded by a spunbond method at a spinning temperature of 220 ° C. The extruded filament is stretched in the traction zone using the suction force of the mobile collection surface, and then deposited on the mobile collection surface through a diffuser to form a side-by-side composite long fiber web having an average fiber diameter of 20.5 μm. Was prepared.
Next, the obtained side-by-side type composite long fiber web was adhered to each other in the same manner as in Example 1 to obtain a composite long fiber non-woven fabric having a basis weight of 18 g / m ² and a number of crimps of 25 / inch. Next, the same aqueous solution of a water permeable agent as in Example 1 was applied to the obtained composite long fiber non-woven fabric under the same coating conditions.
When the measurement reference length on the surface of the obtained non-woven fabric is 100 μm, the ratio of the compartments in which the maximum height in the section is 30% or more with respect to the height (thickness) of the non-woven fabric in the unloaded state is 90%. The water permeability of the non-woven fabric was 45 degrees, the gradient flow length value was 14 mm, the fourth durability water permeability index was 99%, and the wet return index was 0.17 g. The results are shown in Table 1 below.

[Example 14]
An eccentric sheath-core type composite long-fiber non-woven fabric having an average fiber diameter of 20.5 μm, a basis weight of 30 g / m ² , and a number of crimps of 25 / inch was obtained by the same method as in Example 13. Next, the same aqueous solution of a water permeable agent as in Example 1 was applied to the obtained composite long fiber non-woven fabric under the same coating conditions.
The ratio of the compartments in which the maximum height in the compartment when the measurement reference length on the surface of the obtained non-woven fabric is 100 μm is 30% or more with respect to the height (thickness) of the non-woven fabric under no load is 89%. The non-woven fabric had a water permeation of 45 degrees, a gradient flow length value of 14 mm, a fourth durability water permeation index of 99%, and a wet return index of 0.12 g. The results are shown in Table 1 below.

[Example 15]
Polypropylene (PP) with an MFR of 38 g / 10 min is extruded at a spinning temperature of 240 ° C. and a discharge rate of 0.80 g / min / hоle using a spinneret with a C-shaped irregular nozzle, and this filament group is extruded by an air jet. A high-speed airflow traction device was used to extrude toward the mobile collection surface to obtain a long fiber web with an average fiber diameter of 18.7 μm.
Next, the obtained long fiber web was set to a temperature of 135 ° C. and a pressure of 60 kg / cm, and a flat roll and an embossed roll (pattern specifications: diameter 0.425 mm circular, staggered arrangement, horizontal pitch 2.1 mm, vertical pitch 1.1 mm, The fibers were partially adhered to each other through a pressure-bonding area ratio of 6.3%) to obtain a long-fiber non-woven fabric having a grain size of 25 g / m ² and a number of crimps of 28 / inch.
Next, the same aqueous solution of a water permeable agent as in Example 4 was applied to the obtained long fiber non-woven fabric under the same coating conditions.
When the measurement reference length on the surface of the obtained non-woven fabric is 100 μm, the ratio of the compartment in which the maximum height in the compartment is 30% or more with respect to the height (thickness) of the non-woven fabric under no load is 55%. The non-woven fabric had a water permeation of 45 degrees, a gradient flow length value of 23 mm, a fourth durability water permeation index of 89%, and a wet return index of 0.12 g. The results are shown in Table 1 below.

[Comparative Example 1]
A polypropylene (PP) resin having an MFR of 55 g / 10 minutes (measured at a temperature of 230 ° C. and a load of 2.16 kg according to JIS-K7210) is extruded with a single component at a spinning temperature of 220 ° C. by the spunbond method, and this filament group is extruded. A high fiber web with an average fiber diameter of 17.9 μm was prepared by extruding toward a mobile collection surface using a high speed air jet traction device with an air jet.
Next, the obtained web was subjected to a flat roll and an embossed roll at 141 ° C. (pattern specifications: circular 0.425 mm in diameter, staggered arrangement, horizontal pitch 2.1 mm, vertical pitch 1.1 mm, crimping area ratio 6.3%). The fibers were adhered to each other by passing them between them to obtain a long-fiber non-woven fabric in which fibers having a grain size of 18 g / m ² were not crimped.
Next, the same aqueous solution of a water permeable agent as in Example 4 was applied to the obtained long fiber non-woven fabric under the same coating conditions.
The ratio of the compartment in which the maximum height in the compartment when the measurement reference length on the surface of the obtained non-woven fabric is 100 μm is 30% or more with respect to the height (thickness) of the non-woven fabric when no load is applied is 40%. The non-woven fabric had a water permeation 45 degree gradient flow length value of 28 mm, a fourth durable water permeation index of 74%, and a wet return index of 0.56 g. The results are shown in Table 2 below.

[Comparative Example 2]
The long fiber non-woven fabric obtained in Comparative Example 1 has a continuous honeycomb-shaped pattern (embossed concave pattern) having a side of 0.9 mm and a line width of 0.1 mm (pressing area ratio: 12.5%, pattern pitch; vertical 2.8 mm, It was passed between an embossed roll (80 ° C.) having a width of 3.2 mm and a depth of 0.7 mm and a rubber roll having a surface hardness of 60 degrees (JIS-A hardness), and the handle was pressed with a pressure of ² kg / cm ² . A flexible long-fiber non-woven fabric with a high-density area pressed around the hexagonal shell and a raised center was obtained.
Next, the same aqueous solution of a water permeable agent as in Example 4 was applied to the obtained long fiber non-woven fabric under the same coating conditions.
The ratio of the compartment in which the maximum height in the compartment when the measurement reference length on the surface of the obtained non-woven fabric is 100 μm is 30% or more with respect to the height (thickness) of the non-woven fabric when no load is applied is 42%. The non-woven fabric had a water permeation of 45 degrees and a gradient flow length value of 27 mm, a fourth durable water permeation index of 80%, and a rewetting index of 0.68 g. The results are shown in Table 2 below.

[Comparative Example 3]
Using the same components as in Example 1, the discharge rate of the first component is 0.72 g / min · hоle, the discharge rate of the second component is 0.08 g / min · hоle, and the total discharge rate is 0.8 g / min. -Fibers that are hоle and have a ratio of the first component to the second component of 9/1 are extruded at a spinning temperature of 220 ° C. by the spunbond method, and this filament group is moved using a high-speed airflow traction device using an air jet. Extruded toward the collection surface to prepare an eccentric sheath-core type composite long fiber web having an average fiber diameter of 16.7 μm.
Next, the obtained eccentric sheath-core type composite long fiber web was adhered to each other by hot air having a hot air temperature of 142 ° C. and a hot air velocity of 0.7 m / s, and having a grain size of 18 g / m ² and a crimp number of 0 pieces / inch. A composite long fiber non-woven fabric was obtained.
Next, the same aqueous solution of a water permeable agent as in Example 4 was applied to the obtained composite long fiber non-woven fabric under the same coating conditions.
The ratio of the compartment in which the maximum height in the compartment when the measurement reference length on the surface of the obtained non-woven fabric is 100 μm is 30% or more with respect to the height (thickness) of the non-woven fabric when no load is applied is 48%. The non-woven fabric had a water permeation of 45 degrees and a gradient flow length value of 28 mm, a fourth durability water permeation index of 64%, and a wettback index of 0.52 g. The results are shown in Table 2 below.

[Comparative Example 4]
Using the same components as in Example 1, the discharge rate of the first component is 0.54 g / min · hоle, the discharge rate of the second component is 0.26 g / min · hоle, and the total discharge rate is 0.8 g / min. -Fibers that are hоle and have a ratio of the first component to the second component of 1/2 are extruded at a spinning temperature of 220 ° C. by the spunbond method, and this filament group is moved using a high-speed airflow traction device using an air jet. Extruded toward the collection surface to prepare a sheath-core type composite long fiber web having an average fiber diameter of 16.7 μm.
Next, the obtained web was adhered to each other by the same method and conditions as in Comparative Example 3, and then an aqueous solution of a water permeable agent was applied to the obtained composite long fiber non-woven fabric having a basis weight of 18 g / m ² and a crimping number of 0 fibers / inch. Got
The ratio of the compartments in which the maximum height in the compartment when the measurement reference length on the surface of the obtained non-woven fabric is 100 μm is 30% or more with respect to the height (thickness) of the non-woven fabric under no load is 46%. The non-woven fabric had a water permeation of 45 degrees, a gradient flow length value of 26 mm, a fourth endurance water permeation index of 73%, and a wet return index of 0.60 g. The results are shown in Table 2 below.

Since the hydrophilic bulky nonwoven fabric of the present invention has excellent water permeability, it can be suitably used for producing sanitary materials. As for sanitary materials, they can be suitably used for disposable diapers, sanitary napkins, or top sheets on the surface of incontinence pads. Further, the hydrophilic bulky non-woven fabric of the present invention is not limited to the above-mentioned uses, for example, masks, cairo, tape base cloths, patch base cloths, emergency bond base cloths, packaging materials, wipe products, medical gowns, bandages, etc. It can also be used for clothing, skin care sheets, etc.

Claims (10)

A hydrophilic bulky non-woven fabric made of thermoplastic long fibers having a number of crimps of 5 to 45 / 2.54 cm (inch), depending on the X-direction and Y-direction when the measurement reference length on the surface of the non-woven fabric is 100 μm. The ratio of the compartments in which the maximum height in the specified unit compartment is 30% or more with respect to the height (thickness) of the non-woven fabric when no load is applied in the Z direction is 40,000, which corresponds to the non-woven fabric surface surface of 20 mm × 20 mm. The hydrophilic bulky non-woven fabric , which has a non-woven fabric surface structure of 50% or more per hit, and contains or is coated with a water permeable agent . The hydrophilic bulky nonwoven fabric according to claim 1, wherein the orientation index of the hydrophilic bulky nonwoven fabric in the thickness direction by X-ray CT is 0.43 or less. The hydrophilic bulky nonwoven fabric according to claim 1 or 2, wherein the amount of compression work of the hydrophilic bulky nonwoven fabric is 0.20 gf · cm / cm ² or more and 1.00 gf · cm / cm ² or less. The hydrophilic bulky nonwoven fabric according to any one of claims 1 to 3, wherein the thermoplastic fiber is a side-by-side type or an eccentric sheath-core type composite fiber. The hydrophilic bulky non-woven fabric according to any one of claims 1 to 4, wherein the thermoplastic fiber is a polyolefin fiber. The water-permeable material is at least one surfactant selected from the group consisting of higher alcohols, higher fatty acids, nonionic surfactants to which ethylene oxide has been added, alkyl phosphate salts, and anionic activators. The hydrophilic bulky non-woven fabric according to any one of claims 1 to 5. Claims 1 to 1, wherein the water permeable agent is at least one surfactant selected from the group consisting of a polyether compound, a polyethylene ether-modified silicone, a polyether-modified silicone, a polyester compound, a polyamide compound, and a polyglycerin compound. 5. The hydrophilic bulky non-woven fabric according to any one of 5. The hydrophilic bulky non-woven fabric according to any one of claims 4 to 7, wherein the intersections of the composite fibers are melted and adhered to each other. The hydrophilic bulky non-woven fabric according to any one of claims 1 to 8, which is partially thermocompression bonded. A sanitary material using the hydrophilic bulky non-woven fabric according to any one of claims 1 to 9 .

Images