JP2019094584A - Nonwoven fabric - Google Patents

Abstract

To provide a non-woven fabric which is excellent in bulkiness and flexibility and which has a satisfactory level of excellent texture for suitably using as a sanitary material.SOLUTION: A nonwoven fabric of the present invention is composed of a thermoplastic fiber, has a specific volume of 10 cm/g or more, and has a B/A (a value obtained by dividing B by A) of 100 ((mN/200 mm)/mm) or less, where the thickness of the nonwoven fabric measured with a load of 0.2 kPa is A (mm) and a value measured in accordance with the JIS L 1913 (2010 version) Handle-O-meter method is B (mN/200 mm).SELECTED DRAWING: None

Description

  The present invention relates to a nonwoven fabric which is excellent in bulkiness and excellent in flexibility.

  Generally, non-woven fabrics for sanitary materials such as disposable diapers and sanitary napkins are required to have excellent performance in terms of texture because of their comfort when worn. In particular, a good feeling is required for the top sheet in which the buttocks and the like of the wearer are in direct contact with the skin, and the back sheet which is frequently touched at the time of dressing.

  So-called air-through nonwoven fabric in which short fibers represented by a composite fiber consisting of polyethylene terephthalate (PET) and polyethylene (PE) are sheeted by carding and then self-fused by hot air treatment as a nonwoven fabric for sanitary materials Polypropylene spunbond nonwovens are preferably used. The air through non-woven fabric is mainly used as a top sheet for sanitary materials because it is characterized by its excellent bulkiness.

  For the purpose of softening the air-through non-woven fabric, it has been proposed to use divided fibers as the constituent fibers (see Patent Document 1). According to this proposal, there is disclosed a method of obtaining a soft non-woven fabric by dividing fibers by an external force. However, there is a problem that the thickness of the non-woven fabric is inevitably reduced by applying an external force, and the bulkiness is inferior.

  Conventional air through non-woven fabrics have the characteristic of being excellent in bulkiness, but are inferior in flexibility to bending of the non-woven fabrics, and have problems of becoming creases and wrinkles when processed into sanitary materials such as paper diapers . The flexibility to bending and the thickness of the non-woven fabric are in a trade-off relationship, and it was difficult to simultaneously achieve both bulkiness and flexibility to bending.

JP, 2016-102286, A

  Therefore, in view of the above problems, the object of the present invention is to preferably achieve both the excellent bulkiness and flexibility required for the nonwoven fabric for hygienic materials, and the occurrence of creases and wrinkles when used as a hygienic material. It is difficult to provide a nonwoven fabric excellent in quality and texture.

The nonwoven fabric of the present invention is a nonwoven fabric composed of thermoplastic fibers, and the specific volume of the nonwoven fabric is 10 cm ³ / g or more, and the thickness of the nonwoven fabric measured under 2 kPa conditions is A (mm), B / A (value obtained by dividing B by A) (mN / 200 mm) / mm, where B (mN / 200 mm) is the value measured in accordance with JIS L 1913 (2010 version) Handle-O-meter method Is 100 or less.

  According to a preferred embodiment of the non-woven fabric of the present invention, the fibers constituting the non-woven fabric are composed of a composite fiber of two or more components.

Moreover, according to the preferable aspect of the nonwoven fabric of this invention, the initial stage tensile resistance degree of the fiber which comprises said nonwoven fabric is 2000 N / mm < ² > or less.

  According to a preferred embodiment of the non-woven fabric of the present invention, the cross-sectional structure of the fibers constituting the non-woven fabric is any of a concentric core-sheath structure, an eccentric core-sheath structure and a side-by-side structure.

  According to the present invention, the bulkiness and flexibility required for the nonwoven fabric for hygienic materials are made compatible, and at the time of use as a sanitary material, the generation of creases and wrinkles is difficult to occur, and a nonwoven fabric excellent in quality and texture is obtained. .

According to the present invention, the non-woven fabric is composed of thermoplastic fibers, the specific volume of the non-woven fabric is 10 cm ³ / g or more, and the thickness of the non-woven fabric measured under 2 kPa conditions is A (mm). 2010 version) B / A (value of B divided by A) (mN / 200 mm) / mm is 100 or less when B (mN / 200 mm) is the value measured according to the Handle-O-meter method. The non-woven fabric is excellent in bending flexibility with respect to its thickness, so that it is difficult to generate creases when it is bent, and in particular, the quality of the product molded as a sanitary material becomes good and it is suitable for non-woven fabric for sanitary materials Used for

FIG. 1 is a schematic cross-sectional view illustrating the cross section of the fibers constituting the nonwoven fabric of the present invention. FIG. 2 is a schematic cross-sectional view illustrating the cross section of another fiber constituting the nonwoven fabric of the present invention. FIG. 3 is a schematic cross-sectional view illustrating the cross section of another fiber constituting the nonwoven fabric of the present invention.

The nonwoven fabric of the present invention is a nonwoven fabric composed of thermoplastic fibers, and the specific volume of the nonwoven fabric is 10 cm ³ / g or more, and the thickness of the nonwoven fabric measured under 2 kPa conditions is A (mm), B / A (value obtained by dividing B by A) (mN / 200 mm) / mm, where B (mN / 200 mm) is the value measured in accordance with JIS L 1913 (2010 version) Handle-O-meter method Is a non-woven fabric of 100 or less.

  Examples of fibers constituting the non-woven fabric of the present invention include polyolefin fibers such as polypropylene, polyethylene and propylene / ethylene copolymer, and polyesters such as polyethylene terephthalate, polytrimethylene terephthalate and polybutylene terephthalate, and copolymers thereof. Fibers and polyamide fibers such as nylon 6, nylon 66, nylon 12 and the like are preferable from the viewpoints of hydrophobicity, strength, flexibility and the like.

  Polyolefin fibers are particularly preferably used from the viewpoint of hydrophobicity, polyester fibers are preferably used from the viewpoint of dimensional stability and heat resistance, and polyamide fibers are particularly preferably used from the viewpoint of flexibility and touch. .

  The fibers constituting the non-woven fabric of the present invention may be composite fibers or mixed fibers composed of these polymer components, if necessary, and further in the form of a mixture with cellulosic fibers or fibers having other special functions. Is also acceptable.

  In the present invention, among them, composite fibers composed of two raw materials having different melting points are preferably used from the viewpoint of heat adhesion. It is preferable that the difference of melting | fusing point is a combination of 10 degreeC or more as a combination of the raw material of 2 different components.

  As a high melting point component of the raw material which forms the composite fiber used by this invention, polyester, polyamide, polyolefin etc. can be mentioned, for example. Specific examples of the polyester include polyethylene terephthalate, polybutylene terephthalate and potassium trimethylene terephthalate. Moreover, nylon 6, nylon 66, nylon 12 etc. can be mentioned as a specific example of a polyamide. Moreover, polyethylene, a polypropylene, and a propylene ethylene copolymer can be mentioned as an example of polyolefin. Among them, nylon 6, polybutylene terephthalate and polypropylene are preferably used from the viewpoint of flexibility.

  In addition, other components may be copolymerized in the high melting point component constituting the composite fiber, and it is acceptable to contain additives such as particles, a flame retardant and an antistatic agent.

  Examples of other copolymerization components include sodium 5-sulfoisophthalate and 3-hydroxybutanoic acid, and examples of the particles include titanium oxide. Moreover, as a flame retardant, an organic type flame retardant and an inorganic type flame retardant can be mentioned, for example, An alcohol type antistatic agent can be mentioned as an antistatic agent, for example.

  Then, polyethylene or polypropylene can be used as the low melting point component constituting the composite fiber, and polyethylene is particularly preferably used from the viewpoint of adhesiveness. Polyethylenes are classified according to differences in production methods and physical properties, and include high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), etc., which are respectively studied for fibers. Although any polyethylene may be used in the present invention, it is a preferred embodiment to use LLDPE from the viewpoint of spinning stability.

  It is acceptable for polyethylene to be blended with a small amount of other component polymers. Examples of other component polymers include low melting point polyesters and low melting point polyamides, in addition to polyolefin polymers such as polypropylene and poly (4-methyl-1-pentene) whose melting points are close to polyethylene. Further, in order to sufficiently develop the characteristics of polyethylene, the mass ratio of the blend is preferably 5% by mass or less, more preferably 2% by mass or less.

  The melt flow rate of polyethylene (hereinafter sometimes referred to as MFR) is preferably 10 to 100 g / 10 min, more preferably 20 to 40 g / 10 min. The term "melt flow rate" as used herein refers to a value measured at a temperature of 190 ° C and a load of 2.16 kg in accordance with ASTM D1238.

  The raw materials of the fibers used in the present invention include generally used antioxidants, weathering stabilizers, light stabilizers, antistatic agents, fuming agents, antiblocking agents, as long as the effects of the present invention are not impaired. Additives such as lubricants such as polyethylene wax, nucleating agents, and pigments, or other polymers can be added as needed.

  It is preferable that the cross section of the fiber which comprises the nonwoven fabric of this invention consists of two components from which melting | fusing point differs, The mass ratio is preferable 90/10-10/90, and is 70/30-30/70 60/40 to 40/60 is a further preferred embodiment. By setting the mass ratio of the high melting point component to preferably 10% by mass or more, more preferably 30% by mass or more, and further preferably 40% by mass or more, sufficient physical properties can be imparted to the nonwoven fabric. Further, by setting the mass ratio of the low melting point component to preferably 10% by mass or more, more preferably 30% by mass or more, and further preferably 40% by mass or more, sufficient heat adhesion can be obtained.

  As for the cross-sectional shape of the fiber which comprises the nonwoven fabric of this invention, it is preferable that the low melting point component forms at least one part of the fiber surface. Examples of cross-sectional shapes may be concentric core-sheath structures, eccentric core-sheath structures, and side-by-side structures.

  1 to 3 are schematic cross-sectional views illustrating the cross-sections of fibers constituting the nonwoven fabric of the present invention.

  FIG. 1 is a schematic cross-sectional view showing a cross section of a concentric core-in-sheath composite fiber. In FIG. 1, the centers of the core (a) and the sheath (b) are the same. Specifically, the concentric core-in-sheath composite fiber comprises a core (a) and a sheath (b), and the core (a) is surrounded by a polymer different from the core (a) in the cross section of the fiber Sections that extend in the longitudinal direction of the fiber. Further, the sheath portion (b) refers to a portion which is arranged to surround the core portion (a) in the cross section of the fiber and which extends in the longitudinal direction of the fiber.

  FIG. 2 is a schematic cross-sectional view showing a cross section of the eccentric core-sheath type composite fiber. In FIG. 2, the centers of the core (a) and the sheath (b) are different. Specifically, the eccentric core-sheath type composite fiber comprises a core (a) and a sheath (b), and the core (a) is at least a polymer different from the core (a) in the cross section of the fiber It refers to a portion that is arranged to be partially enclosed and extends along the length of the fiber. In addition, the sheath portion (b) refers to a portion which is arranged to surround at least a part of the core portion (a) in the cross section of the fiber and which extends in the longitudinal direction of the fiber. The eccentric core-sheath type composite fiber includes an exposed type in which the side surface of the core portion (a) is exposed and a non-exposed type in which the side surface of the core portion (a) is not exposed. In the present invention, non-exposed eccentric core / sheath composite fibers are preferably used in view of spinning stability.

  FIG. 3 is a schematic cross-sectional view showing a cross section of the side-by-side type composite fiber. The side-by-side type composite fiber has a structure in which a first component (c) and a second component (d) are laminated. The bonding surface of the two components may be either linear or curved, and varies depending on the viscosity characteristics of the two components and the discharge amount ratio. The cross section of the fiber may be circular, or it may be a modified cross section such as oval.

  The average single fiber diameter of the fibers used in the nonwoven fabric of the present invention is preferably 7 μm or more and 22 μm or less, more preferably 8 μm or more and 21 μm or less, and still more preferably 10 μm or more and 20 μm or less. The average single fiber diameter is preferably 7 μm or more from the viewpoint of spinning stability, and the thinner the average single fiber diameter, the more the bonding points of the fibers as a non-woven fabric, so the strength is high and the flexibility is good. Moreover, since it is used for a sanitary material, it is a preferable aspect that an average single fiber diameter is 22 micrometers or less from a strong viewpoint of the nonwoven fabric for sanitary materials.

The nonwoven fabric of the present invention preferably has a basis weight of 3 to 200 g / m ² . The above-mentioned basis weight is more preferably 5 to 150 g / m ² , still more preferably 10 to 100 g / m ² . By setting the basis weight in the above range, sufficient flexibility can be imparted to the non-woven fabric.

The initial tensile resistance of fibers used in the nonwoven fabric of the present invention is preferably 2000 N / mm ² or less. By setting the initial tensile resistance of the fiber to preferably 2000 N / mm ² or less, more preferably 1500 N / mm ² or less, and even more preferably 1000 N / mm ² or less, it is possible to obtain a nonwoven fabric having good flexibility for bending. . Furthermore, even when the thickness of the non-woven fabric is finished thick, it is difficult for the non-woven fabric to be creased and creased, and both bulkiness and flexibility can be achieved. In addition, the initial tensile resistance is preferably 500 N / mm ² or more from the viewpoint of processability to a non-woven fabric, handling when made into a non-woven fabric, and processability to a sanitary material.

Moreover, it is important that the specific volume of the nonwoven fabric of this invention is 10 cm < ³ > / g or more. The specific volume referred to here indicates the volume per unit mass of the nonwoven fabric, and it can be judged that the higher the numerical value, the better the bulkiness of the nonwoven fabric. When using for sanitary materials, such as a paper diaper, since cushioning property can be provided so that the specific volume of a nonwoven fabric is high and it is excellent in bulkiness, it is a desirable mode. The specific volume is preferably 100 cm ³ / g or less in view of the use as a nonwoven fabric for sanitary materials.

From the same viewpoint, the apparent density of the nonwoven fabric of the present invention is preferably 0.100 g / cm ³ or less. The apparent density can be calculated by dividing the basis weight by the thickness. Apparent density is more preferably 0.09 g / cm ³ or less, more preferably 0.080 g / cm ³ or less. By setting the apparent density to the above range, sufficient bulkiness can be obtained when using as a non-woven fabric. The apparent density is preferably 0.01 g / cm ³ or more in view of the use as a nonwoven fabric for sanitary materials.

  It is preferable that the thickness measured on 2 kPa conditions of the nonwoven fabric of this invention is 0.20 mm or more. By setting the thickness of the non-woven fabric to 0.20 mm or more, the non-woven fabric does not become too hard, and when used for sanitary materials such as paper diapers, it can be made to have an appropriate texture. The thickness of the non-woven fabric is preferably as high as possible, but is preferably 2 mm or less from the viewpoint of use for sanitary materials such as disposable diapers.

  It is preferable that the value of the handle odometer measured based on JIS L 1913 (2010 year version) of the nonwoven fabric of this invention is 10 mN / 200 mm or more and 200 mN / 20 mm or less. Here, the value of the handle odometer indicates the sum of the values measured in the longitudinal direction and the lateral direction of the nonwoven fabric. By setting the value of the handle ohm meter to 10 mN / 20 mm or more, preferably 20 mN / 100 mm or more, and more preferably 30 mN / 200 mm, the rigidity can be made to the extent that sanitary materials such as disposable diapers can be processed. By setting the value of handle ohm meter to 200 mN / 200 mm or less, preferably 180 mN / 20 mm or less, more preferably 160 mN / 20 mm or less, it is possible to achieve excellent flexibility against bending of the non-woven fabric, such as paper diapers When processed into a hygienic material, it becomes difficult to generate wrinkles at a bent portion, and a hygienic material excellent in quality and texture can be obtained.

  In the nonwoven fabric of the present invention, the thickness of the nonwoven fabric measured with a load of 0.2 kPa is A (mm), and the value measured according to JIS L 1913 (2010 version) Handle-O-meter method is B (mN / 200 mm It is important that B / A (a value obtained by dividing B by A) when it is 100) is 100 ((mN / 200 mm) / mm) or less.

  By setting the value B / A to 100 ((mN / 200 mm) / mm) or less, preferably 80 ((mN / 200 mm) / mm) or less, and more preferably 60 ((mN / 200 mm) / mm) or less It is compatible with the bulkiness required for nonwovens for sanitary materials and flexibility for bending, and when processed into sanitary materials such as disposable diapers, it is possible to reduce the wrinkles generated due to the bending of the nonwovens, and it is possible to It can be an excellent sanitary material. The value of B / A is preferably 10 ((mN / 200 mm) / mm) or more from the viewpoint of handleability when made into a non-woven fabric and processability to a sanitary material.

  Next, an example of a method for producing the nonwoven fabric of the present invention will be described.

  As the non-woven fabric of the present invention, a long-fiber non-woven fabric obtained by a spun bond method or a melt-blowing method, or an air-through non-woven fabric obtained by subjecting short fibers to a fiber web using a card and subjecting it to hot air treatment Can. Among them, an air through non-woven fabric is preferably used because a high bulkiness can be obtained. As a method of manufacturing the nonwoven fabric of the present invention, a method of manufacturing an air through nonwoven fabric can be applied.

  The air through method is a manufacturing method in which short fibers, which are raw cotton, are passed through a carding machine to open the short fibers, form into a fiber web, and then form a non-woven fabric by heat treatment.

  With regard to the heat treatment method, for example, heat adhesion by hot air treatment, fusion by ultrasonic waves, a heat embossing roll in which engravings (concave and convex portions) are respectively formed on the upper and lower pair of roll surfaces, and one roll surface is flat (smooth) Thermocompression bonding using various rolls such as a hot embossing roll consisting of a combination of a roll and a roll with engraving (uneven part) on the other roll surface, and a hot calender roll consisting of a combination of upper and lower flat (smooth) rolls Each combination can be applied.

  Among them, thermal adhesion by hot air treatment is particularly preferable because it can maintain the thickness of the non-woven fabric. In the case of heat bonding by hot air treatment, the temperature of the hot air is preferably in the range of the melting point of the low melting point component + 1 ° C to + 30 ° C, more preferably in the range of + 1 ° C to + 15 ° C, and still more preferably + 1 ° C to +10. It is in the range of ° C. By setting the hot air temperature to the melting point of the low melting point component + 1 ° C or higher, sufficient heat adhesion can be obtained.

  In addition, by setting the hot air temperature to preferably not more than the melting point of the low melting point resin of + 30 ° C., more preferably to + 15 ° C. or less, and further preferably to 10 ° C. or less, curing of the nonwoven fabric due to heat can be suppressed. As a non-woven fabric for sanitary materials, soft texture can be maintained.

  The amount of hot air is preferably 1.0 to 5.0 m / sec. By setting the amount of hot air to 1.0 m / sec or more, the hot air can be ventilated to the nonwoven fabric for sanitary materials, and sufficient adhesiveness can be obtained. On the other hand, by setting the amount of hot air to 5.0 m / sec or less, web disturbance during heat treatment can be suppressed.

  Subsequently, a heat treatment of calendering or embossing may be preferably employed for the purpose of setting the thickness of the non-woven fabric to a predetermined thickness.

  The embossed bonding area rate in embossing is preferably 5 to 30%. By setting the adhesion area to preferably 5% or more, and more preferably 10% or more, practically usable strength can be obtained. On the other hand, by setting the embossing adhesion area ratio to preferably 30% or less, more preferably 20% or less, a soft texture can be maintained.

  The term “emboss adhesion area ratio” as used herein refers to the entire nonwoven fabric in a portion where the convex portion of the upper roll and the convex portion of the lower roll overlap and abut on the non-woven web when heat bonding is performed by a pair of uneven rolls. It refers to the ratio occupied. When heat treatment is performed using a roll having irregularities and a flat roll, the ratio of the convex portion of the roll having irregularities to the whole nonwoven fabric of the portion in contact with the nonwoven web is said.

  As the shape of the engraving applied to the heat embossing roll, shapes such as circular, oval, square, rectangular, parallelogram, rhombus, regular hexagon and regular octagon can be used.

  The surface temperature of the heat embossing roll is preferably −50 to −1 ° C. with respect to the melting point of the lowest melting resin among the resins used. The surface temperature of the heat embossing roll is preferably −50 ° C. or higher, more preferably −30 ° C. or higher, more preferably −10 ° C. or higher with respect to the melting point of the low melting point resin. Can make it easy to suppress the occurrence of fluff.

  In addition, by setting the surface temperature of the heat embossing roll to be preferably −1 ° C. or less with respect to the melting point of the low melting point resin, it is possible to easily prevent the occurrence of peeling between the resins due to melting of the fibers.

  The linear pressure of the roll during heat treatment by calendering or embossing is preferably 10 to 500 N / cm. When the linear pressure is preferably 10 N / cm or more, more preferably 15 N / cm or more, and further preferably 20 N / cm or more, sufficient heat treatment can be performed, and the thickness can be controlled. On the other hand, by maintaining the above linear pressure preferably at 500 N / cm or less, more preferably at 400 N / cm or less, more preferably at 300 N / cm or less, the texture of the non-woven fabric is maintained by not exerting too much stress on the roll. can do. The linear pressure of the roll can be suitably adjusted by the thickness of the target nonwoven fabric.

  Moreover, it is preferable that the temperature of the roll at the time of the heat processing by a calender or embossing is below 1 degreeC with respect to melting | fusing point of low melting resin. By setting the roll temperature to −1 ° C. or less with respect to the melting point of the low melting point component, it is possible to prevent the surface of the non-woven fabric after heat treatment from curing. Roll temperature can be suitably adjusted with the thickness of the target nonwoven fabric.

  Since the nonwoven fabric of the present invention is very excellent in texture, it can be suitably used particularly for top sheets and back sheets such as disposable diapers and napkins.

  Next, the nonwoven fabric of the present invention and the method for producing the same will be specifically described based on examples.

(1) Average fiber diameter of single fiber (μm):
The non-woven fabric was observed at a magnification of 500 with a scanning electron microscope (VE-7800 manufactured by SEM Keyence), and the diameters of 50 randomly extracted single fibers were measured. This was done in three places, the diameter of a total of 150 single fibers was measured, and the decimal point was rounded off to calculate the average value. When the fiber cross section was a non-uniform cross section, the cross section area of the single fiber was first measured, and the average fiber diameter of the single fiber was determined by calculating the diameter when the cross section was regarded as circular.

(2) Initial tensile resistance of fiber (N / mm ² )
The initial tensile resistance of the fiber was measured according to JIS L 1015 (2010 version) using a TENSILON tensile tester (RTG-1250 manufactured by Baldwin).

(3) Non-woven fabric basis weight (g / m ² );
The basis weight of the non-woven fabric is based on 6.2 “mass per unit area” of JIS L 1913 (2010 edition), and three 20 cm × 25 cm test pieces are collected per 1 m width of the sample, and each mass in the standard condition (g) weighed, representing the average value in 1 m ² per mass (g / ^{m 2).}

(4) Thickness of non-woven fabric (mm);
The thickness of the non-woven fabric was measured in accordance with JIS L 1908 (2010 version). Prepare a presser foot with an area of 2500 mm ² . Measure the thickness after applying a pressure of 2 kPa for a fixed period of time to a test piece of 1.75 times or more the diameter of the presser foot. The average value for 10 test pieces was calculated, and the value was taken as the thickness.

(5) Specific volume of non-woven fabric (cm ³ / g);
The specific volume of the non-woven fabric was calculated from the basis weight and thickness of the non-woven fabric measured above. The higher the value, the better the bulkiness.

(6) Softness of non-woven fabric (handle-o-meter method);
Measured in accordance with the JIS L 1913 (2010 version) Handle-O-meter method. Three samples of size 200 mm × 200 mm are collected. Place the measurement direction of the sample perpendicular to the slot (20 mm) on the sample table, lower the blade adjusted to drop to 8 mm from the sample table surface, press the sample, and calculate the maximum pressure value at that time read. For each sample, measurement is made at a position 67 mm (1/3 of the sample width) from any one side, at different positions in the vertical and horizontal directions. Each sample was measured at 4 points in the vertical direction and at 4 points in the horizontal direction, and the average value of values obtained by measuring a total of 3 samples was calculated.

Example 1
(raw cotton)
The core and sheath shown in FIG. 1 are made of nylon 6 having a melting point of 220 ° C. and an 高 密度 r of 2.7 as the core component and high density polyethylene having a melting point of 130 ° C. and an MFR of 18 g / 10 min as the sheath component. Using a composite die, undrawn yarn was obtained under the conditions of a core / sheath composite mass ratio of 50/50, a single hole discharge amount of 0.7 g / min, and a spinning speed of 1100 m / min. Subsequently, the film was drawn 3.2 times under the condition of a liquid bath temperature of 90 ° C., and then cut into 51 mm to obtain a raw cotton of core-sheath type composite fiber. The average single fiber diameter of the obtained core-sheath type composite base cotton was 18.2 μm, and the initial tensile resistance was 940 N / mm ² .

(Non-woven fabric)
The raw fiber of the above-mentioned core-sheath composite fiber was used to form a laminated fiber web through a carding process. Next, the resulting laminated fiber web is heat treated using a heat treatment machine for 12 seconds at a temperature of 160 ° C. and a hot air volume of 3.3 m / min, and then the temperature is raised using a calender device of upper and lower flat rolls. Heat treatment was carried out under conditions of 30 ° C. and a linear pressure of 160 N / cm to obtain a non-woven fabric. The obtained nonwoven fabric had a basis weight of 20 g / m ² , a thickness of 1.0 mm, a specific volume of 50 cm ³ / g, and a measured value of the handle odometer of 24 mN / 20 mm in the vertical direction and 13 m / 20 mm in the horizontal direction. . The value obtained by dividing the measured value of the steering wheel ometer measured by the measurement result by the thickness was 37 (mN / 20 mm) / mm, and the nonwoven fabric was very excellent in bulkiness and flexibility to bending. The evaluation results are shown in Table 1.

(Example 2)
Core-sheath composite mass ratio using polybutylene terephthalate having a melting point of 227 ° C. and an intrinsic viscosity of 0.85 dl / g as the core component and high density polyethylene having a melting point of 130 ° C. and an MFR of 18 g / 10 min as the sheath component Are the same as in Example 1 except that core / sheath composite fibers having an average single fiber diameter of 19.4 μm, an initial tensile resistance of 1360 N / mm ² , and a cut length of 51 mm are used as raw cotton. I got a non-woven fabric. The obtained nonwoven fabric had a basis weight of 20 g / m ² , a thickness of 1.1 mm, a specific volume of 55 cm ³ / g, and a measured value of the handle odometer of 58 mN / 20 mm in the vertical direction and 34 m / 20 mm in the horizontal direction. . The value obtained by dividing the measured value of the steering wheel ometer measured by the measurement result by the thickness was 84 (mN / 20 mm) / mm, and the nonwoven fabric was excellent in bulkiness and flexibility to bending. The evaluation results are shown in Table 1.

(Comparative example 1)
Core / sheath composite mass ratio using a polyethylene terephthalate having a melting point of 260 ° C. and an intrinsic viscosity of 0.65 dl / g as the core component and a high density polyethylene having a melting point of 130 ° C. and an MFR of 18 g / 10 min as the sheath component Non-woven fabric in the same manner as in Example 1 except that core / sheath composite fibers having an average single fiber diameter of 17.8 μm, an initial tensile resistance of 2600 N / mm ² , and a cut length of 51 mm were used as raw cotton. I got The obtained nonwoven fabric had a basis weight of 20 g / m ² , a thickness of 1.2 mm, a specific volume of 60 cm ³ / g, and a measured value of the handle odometer of 78 mN / 20 mm in the vertical direction and 49 m / 20 mm in the horizontal direction. . The value obtained by dividing the measured value of the steering wheel ometer by the thickness, which is calculated from the measurement result, is 106 (mN / 20 mm) / mm, and although excellent in bulkiness, the initial tensile resistance of the fiber is high. And the flexibility to bending was inferior. The evaluation results are shown in Table 1.

In Example 1 and Example 2 of the present invention, the specific volume of the non-woven fabric is 10 cm ³ / g or more, and the value obtained by dividing the measured value of the handle ometer by the thickness is 100 (mN / 20 mm) / mm or less It was a nonwoven fabric excellent in bulkiness and flexibility to bending. In particular, Example 1 was a non-woven fabric having very good flexibility for bending because the initial tensile resistance of the fibers constituting the non-woven fabric was low. These non-woven fabrics can be made into high-quality hygienic materials because they are less likely to generate creases and wrinkles when they are processed into hygienic materials such as disposable diapers, and can be used very suitably.

  On the other hand, although Comparative Example 1 is excellent in bulkiness, the value of the handle メ ー タ meter is high, the flexibility to bending is inferior, and when the nonwoven fabric is bent, creases are easily generated, and hygiene such as paper diapers It was a level which wrinkles generate notably at the time of processing into material.

(A): core part (b): sheath part (c): first component (d): second component

Claims (4)

A non-woven fabric composed of thermoplastic fibers, wherein the specific volume of the non-woven fabric is 10 cm ³ / g or more, and the thickness of the non-woven fabric measured with a load of 0.2 kPa is A (mm), JIS L 1913 (2010 B / A (value obtained by dividing B by A) is 100 ((mN / 200 mm) / mm), where B (mN / 200 mm) is the value measured in accordance with the Handle-O-meter method. The nonwoven fabric characterized by being the following.   The non-woven fabric according to claim 1, wherein the fibers constituting the non-woven fabric are composed of bicomponent or more composite fibers. The nonwoven fabric according to claim 1 or 2, wherein an initial tensile resistance of fibers constituting the nonwoven fabric is 2000 N / mm ² or less.   The non-woven fabric according to any one of claims 1 to 3, wherein the cross-sectional structure of the fibers constituting the non-woven fabric is any of a concentric core-sheath structure, an eccentric core-sheath structure and a side-by-side structure.

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