Non-woven fabric and article

Abstract

Disclosed are a non-woven fabric and an article. The disclosed non-woven fabric comprises core-sheath type composite fibers in which the degree of crystal orientation of the sheath part is lower than the degree of crystal orientation of the core part, the difference in the degree of crystal orientation between the core part and the sheath part being 0.5 to 2.5.

Description

Nonwoven fabrics and articles

[0001] Nonwoven fabrics and articles are disclosed. More specifically, nonwoven fabrics and articles having excellent processability and low liquid permeability are disclosed.

[0002] Nonwoven fabrics are used for a variety of purposes, including industrial applications such as medical, protective clothing and masks, and sanitary products such as diapers and sanitary pads.

[0003] Conventional non-woven fabrics had a problem with adhesives used in diaper manufacturing lines seeping out due to stretching.

[0004] One embodiment of the present invention provides a nonwoven fabric having excellent processability and low liquid permeability.

[0005] Another embodiment of the present invention provides an article comprising the nonwoven fabric.

[0006] One aspect of the present invention is:

[0007] It includes a core-sheath type composite fiber in which the crystal orientation of the core is lower than that of the core,

[0008] The above-mentioned core and the above-mentioned superstructure provide a nonwoven fabric having a difference in crystal orientation of 0.5 to 2.5.

[0009] The above-mentioned core-type composite fiber may include a core having a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 20 to 80 g / 10 min as measured according to ASTM D1238, and a sheath having a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 35 to 115 g / 10 min as measured according to ASTM D1238.

[0010] The melting rate of the above-mentioned first part may be 15 to 35 g / 10 min greater than that of the above-mentioned deep part.

[0011] The weight ratio of the above-mentioned core to the above-mentioned superstructure can be 30 to 80:20 to 70.

[0012] The core may comprise a first polypropylene, and the upper portion may comprise a second polypropylene.

[0013] The above-mentioned core-type composite fiber may have a fineness of 1.4 to 2.0 denier.

[0014] The above nonwoven fabric may have an MD tensile strength of 3.0 to 4.5 kgf / 5 cm, a CD tensile strength of 1.2 to 2.4 kgf / 5 cm, an MD stiffness of 30 to 60 mm, a CD stiffness of 20 to 50 mm, a friction coefficient of 0.2 to 0.40 μs, and a water pressure resistance of 60 to 100 mmH2O.

[0015] The above nonwoven fabric may be a spunbond nonwoven fabric.

[0016] The above nonwoven fabric may be composed of two or more layers.

[0017] Another aspect of the present invention is:

[0018] An article including the above nonwoven fabric is provided.

[0019] A nonwoven fabric and an article comprising the same according to one embodiment of the present invention have the advantages of excellent processability and low liquid permeability.

[0020] Figure 1 is a cross-sectional view of a core-type composite fiber constituting a nonwoven fabric according to one embodiment of the present invention.

[0021] Figure 2 is a cross-sectional view of a side-by-side composite fiber constituting a nonwoven fabric according to Comparative Example 7.

[0022] Hereinafter, a nonwoven fabric according to one embodiment of the present invention will be described in detail.

[0023] A nonwoven fabric according to one embodiment of the present invention includes a core-sheath type composite fiber having a crystal orientation degree of the sheath portion lower than a crystal orientation degree of the core portion.

[0024] The difference in crystal orientation between the core and the sheath may be 0.5 to 2.5. When the difference in crystal orientation between the core and the sheath is within the above range, the nonwoven fabric may have excellent processability and low liquid permeability. When the nonwoven fabric has low liquid permeability, the adhesive may not seep through to the surface of the diaper.

[0025] (i) The crystal orientation of the core, (ii) the crystal orientation of the sheath, and (iii) the difference in crystal orientation between the core and the sheath can be controlled by the melt flow rate, the spinning speed, and the discharge amount per hole during spinning. The lower the melt flow rate, the higher the spinning speed, and the higher the discharge rate per hole during spinning, the higher the crystal orientation generally becomes. For example, the melt flow rate (MFR) of the core may be 30 to 40 g / 10 min, the melt flow rate (MFR) of the sheath may be 50 to 80 g / 10 min, the spinning speed may be 2,300 to 3,000 m / min, and the discharge amount per hole during spinning may be 0.40 to 0.65 g / min hole.

[0026] In the above-mentioned core-type composite fiber, the crystal orientation of the core and the crystal orientation of the sheath are evaluated by the following methods:

[0027] (1) 20 core fibers and 20 sheath fibers cut from nonwoven fabric are arranged so that the fiber axes are in the same direction.

[0028] (2) For the sample organized in (1) above, wide-angle X-ray diffraction measurement is performed using an X-ray diffraction device.

[0029] (3) Obtain a circumferential X-ray diffraction profile of a peak corresponding to the (110) plane and an equatorial X-ray diffraction profile.

[0030] (4) From the peak half-width H(°) of the X-ray diffraction profile in the circumferential direction and the peak half-width βe(°) of the X-ray diffraction profile in the equatorial direction, each value is calculated using the following equation.

[0031] ·Crystal orientation π=(180-H) / 180

[0032] ·Crystal size L(nm)=0.9λ / ((β e 2 -β0 2 ) 0.5 ×cosθ)

[0033] (In the formula, λ represents the incident X-ray wavelength (0.15418 nm in this specification), β0 represents the correction value of the half width (0.46° in this specification), and θ represents the Bragg angle (°) of the peak top.)

[0034]

[0035] The above-mentioned core-type composite fiber may include a core having a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 20 to 80 g / 10 min as measured according to ASTM D1238, and a sheath having a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 35 to 115 g / 10 min as measured according to ASTM D1238.

[0036] Additionally, the melting rate of the above-mentioned portion may be 15 to 35 g / 10 min greater than that of the above-mentioned deep portion.

[0037] The weight ratio of the core to the base may be 30 to 80:20 to 70. When the weight ratio of the core to the base is within the above range, the nonwoven fabric may have excellent processability and low liquid permeability.

[0038] Additionally, the core may include a first polypropylene, and the upper portion may include a second polypropylene.

[0039] The first polypropylene polymer and the second polypropylene polymer may be manufactured using a highly stereoregular polymerization catalyst.

[0040] The above-mentioned high stereoregularity polymerization catalyst may include a catalyst of a diester component, a catalyst of a succinate component, a metallocene catalyst, or a combination thereof.

[0041] The above-mentioned core-type composite fiber may have a fineness of 1.4 to 2.0 denier. When the fineness of the above-mentioned core-type composite fiber is within the above range, the nonwoven fabric may have excellent processability and low liquid permeability.

[0042] The above nonwoven fabric may further contain a softener.

[0043] The above softener may include an erucamide-based softener, a wax emulsion, a reactive softener, a silicone-based softener, a surfactant, an ester compound, an ethylene bis stearamide-based softener, an ethylene-propylene random copolymer, an ethylene-butenepropylene copolymer, or a combination thereof.

[0044] Additionally, the above-mentioned softener can be used in the form of a master batch chip manufactured by melt-mixing it with a polymer such as polypropylene.

[0045] In addition, the content of the softener (i.e., the softener component excluding the polymer in the master batch chip) may be 0.5 to 30 parts by weight per 100 parts by weight of the nonwoven fabric.

[0046] Figure 1 is a cross-sectional view of a core-type composite fiber (100) constituting a nonwoven fabric according to one embodiment of the present invention.

[0047] Referring to FIG. 1, the core-type composite fiber (100) may include a core (110) and a sheath (120) configured to surround the core (110).

[0048] The above nonwoven fabric may have an MD tensile strength of 3.0 to 4.5 kgf / 5 cm, a CD tensile strength of 1.2 to 2.4 kgf / 5 cm, an MD stiffness of 30 to 60 mm, a CD stiffness of 20 to 50 mm, a friction coefficient of 0.2 to 0.40 μs, and a water pressure resistance of 60 to 100 mmH2O.

[0049] The above nonwoven fabric may be a spunbond nonwoven fabric.

[0050] The above nonwoven fabric may be composed of two or more layers. For example, the above nonwoven fabric may be a nonwoven laminate.

[0051] The basic weight of the above nonwoven fabric can be appropriately selected depending on the purpose, and the basic weight is usually 15 to 100 g / m. 2 , for example, 7~30 g / m 2 It could be.

[0052] The above-mentioned core-type composite fiber may further include additives as needed, in addition to the first polypropylene-based polymer and the second polypropylene-based polymer, within a range that does not impair the purpose of the present invention. The additives may include known heat-resistant stabilizers, weather-resistant stabilizers, various stabilizers, antistatic agents, antiblocking agents, anticlouding agents, fillers, dyes, pigments, natural oils, synthetic oils, waxes, or combinations thereof.

[0053] The above stabilizers include anti-aging agents such as 2,6-di-t-butyl-4-methylphenol (BHT); phenolic antioxidants such as tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate]methane, β-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid alkyl ester, and 2,2'-oxamidobis[ethyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate; fatty acid metal salts such as zinc stearate, calcium stearate, and calcium 1,2-hydroxystearate; polyhydric alcohol fatty acid esters such as glycerin monostearate, glycerin distearate, pentaerythritol monostearate, pentaerythritol distearate, and pentaerythritol tristearate; or combinations thereof.

[0054] The filler may include silica, diatomaceous earth, alumina, titanium oxide, magnesium oxide, pumice powder, pumice balloon, aluminum hydroxide, magnesium hydroxide, basic magnesium carbonate, dolomite, calcium sulfate, potassium titanate, barium sulfate, calcium sulfite, talc, clay, mica, asbestos, calcium silicate, montmorillonite, bentonite, graphite, aluminum powder, molybdenum sulfide, or a combination thereof.

[0055] The above-described propylene polymer and the additives used as needed can be mixed using a known method.

[0056] Hereinafter, a method for manufacturing a nonwoven fabric according to one embodiment of the present invention will be described in detail.

[0057] A method for manufacturing a nonwoven fabric according to one embodiment of the present invention includes a step (S10) of melting a core-forming polymer and a sheath-forming polymer using separate extruders to form a core-forming melt and a sheath-forming melt, a step (S20) of discharging each of the melts through a spinneret having a composite spinning nozzle configured to form a desired fiber structure and discharging the melt to emit composite fibers, a step (S30) of cooling and drawing the released composite fibers, and a step (S40) of collecting the cooled and drawn composite fibers on a collecting belt and depositing them at a predetermined thickness to form a nonwoven fabric.

[0058] In the above step (10), a softener may be added to at least one of the core-forming polymer and the sheath-forming polymer. In this case, the method of adding the softener to at least one of the core-forming polymer and the sheath-forming polymer is as described above.

[0059] In the above step (S20), the temperature of the radiation detention can be maintained at 230 to 250°C.

[0060] The above step (S30) may be a step of cooling the composite fiber released in the above step (S20) by cooling air and also applying tension by drawing air to give it a predetermined fineness.

[0061] In addition, the method for manufacturing the nonwoven fabric may further include a step (S50) of imparting mechanical properties to the nonwoven fabric formed in the step (S40).

[0062] The above step (S50) can be performed by a method using a needle punch, water jet, ultrasonic wave, etc. as a bridging process, an embossing process using a heated embossing roll, or a method of heat-sealing by high-temperature ventilation.

[0063] Hereinafter, an article according to one embodiment of the present invention will be described in detail.

[0064] An article according to one embodiment of the present invention comprises the nonwoven fabric described above.

[0065] The above article may be a diaper, absorbent article, disposable sanitary article, excrement article, side gather, support layer or top sheet.

[0066] Hereinafter, the present invention will be described in more detail through examples. These examples are intended to explain the present invention more specifically, and the scope of the present invention is not limited to these examples.

[0067] Example 1: Preparation of nonwoven fabric

[0068] A nonwoven fabric composed of core-type composite fibers (100) having the structure of Fig. 1 was manufactured by the following method. Specifically, 55 parts by weight of a first polypropylene (PP1) for core formation and 45 parts by weight of a second polypropylene (PP2) for sheath formation were melted by separate extruders to form a core-type melt and a sheath-type melt. Thereafter, each of the melts was discharged through a spinneret having a composite spinning nozzle. Thereafter, each of the discharged melts was cooled by cooling air and tension was applied by drawing air to have a fineness of 1.7 denier. Thereafter, the cooled and drawn composite fibers were collected on a collecting belt and deposited to a predetermined thickness to form a nonwoven fabric. Thereafter, mechanical properties were imparted to the formed nonwoven fabric by embossing using a heated embossing roll. As a result, a nonwoven fabric was obtained. At this time, the melt flow rate of the first polypropylene (PP1) for forming the core, the melt flow rate of the second polypropylene (PP2) for forming the sheath, the spinning speed, and the amount of discharge per hole during spinning were adjusted so that the difference in crystal orientation (crystal orientation of the core - crystal orientation of the sheath) in the core-type composite fiber was 1.5.

[0069] The crystal orientation was measured and calculated using the following devices and conditions.

[0070] · Device: Rigaku SmartLab (enclosed tube type)

[0071] ·X-ray source: CuKα rays (Ni filter used)

[0072] Output: 40kV 50mA

[0073] ·Detector: D / teX one-dimensional detector

[0074] · Entrance slit: 2mmhХ2.2mmw

[0075] ·Light receiving slit: 5mm-mm.

[0076] Example 2: Preparation of nonwoven fabric

[0077] A nonwoven fabric was manufactured in the same manner as in Example 1, except that 30 parts by weight of the first polypropylene (PP1) for core formation and 70 parts by weight of the second polypropylene (PP1) for sheath formation were used.

[0078] Example 3: Preparation of nonwoven fabric

[0079] A nonwoven fabric was manufactured in the same manner as in Example 1, except that 80 parts by weight of the first polypropylene (PP1) for core formation and 20 parts by weight of the second polypropylene (PP2) for sheath formation were used.

[0080] Example 4: Preparation of nonwoven fabric

[0081] A nonwoven fabric was manufactured in the same manner as in Example 1, except that the melt flow rate of the first polypropylene (PP1) for forming the core, the melt flow rate of the second polypropylene (PP2) for forming the core, the spinning speed, and the amount of discharge per hole during spinning were changed so that the difference in crystal orientation (crystal orientation of the core - crystal orientation of the core) was 0.5.

[0082] Example 5: Preparation of nonwoven fabric

[0083] A nonwoven fabric was manufactured in the same manner as in Example 1, except that the melt flow rate of the first polypropylene (PP1) for forming the core, the melt flow rate of the second polypropylene (PP2) for forming the core, the spinning speed, and the amount of discharge per hole during spinning were changed so that the difference in crystal orientation (crystal orientation of the core - crystal orientation of the core) was 2.5.

[0084] Example 6: Preparation of nonwoven fabric

[0085] A nonwoven fabric was manufactured in the same manner as in Example 1, except that the stretching conditions were changed so that the fineness of the core-type composite fiber became 1.4 denier.

[0086] Example 7: Preparation of nonwoven fabric

[0087] A nonwoven fabric was manufactured in the same manner as in Example 1, except that the stretching conditions were changed so that the fineness of the core-type composite fiber became 2.0 denier.

[0088] Comparative Example 1: Manufacturing of nonwoven fabric

[0089] A nonwoven fabric was manufactured in the same manner as in Example 1, except that 25 parts by weight of the first polypropylene (PP1) for core formation and 75 parts by weight of the second polypropylene (PP2) for sheath formation were used.

[0090] Comparative Example 2: Manufacturing of nonwoven fabric

[0091] A nonwoven fabric was manufactured in the same manner as in Example 1, except that 85 parts by weight of the first polypropylene (PP1) for core formation and 15 parts by weight of the second polypropylene (PP2) for sheath formation were used.

[0092] Comparative Example 3: Manufacturing of nonwoven fabric

[0093] A nonwoven fabric was manufactured in the same manner as in Example 1, except that the melt flow rate of the first polypropylene (PP1) for forming the core, the melt flow rate of the second polypropylene (PP2) for forming the core, the spinning speed, and the amount of discharge per hole during spinning were changed so that the difference in crystal orientation (crystal orientation of the core - crystal orientation of the core) was 0.2.

[0094] Comparative Example 4: Manufacturing of nonwoven fabric

[0095] A nonwoven fabric was manufactured in the same manner as in Example 1, except that the melt flow rate of the first polypropylene (PP1) for forming the core, the melt flow rate of the second polypropylene (PP2) for forming the core, the spinning speed, and the amount of discharge per hole during spinning were changed so that the difference in crystal orientation (crystal orientation of the core - crystal orientation of the core) was 3.0.

[0096] Comparative Example 5: Manufacturing of nonwoven fabric

[0097] A nonwoven fabric was manufactured in the same manner as in Example 1, except that the stretching conditions were changed so that the fineness of the core-type composite fiber became 1.1 denier.

[0098] Comparative Example 6: Manufacturing of nonwoven fabric

[0099] A nonwoven fabric was manufactured in the same manner as in Example 1, except that the stretching conditions were changed so that the fineness of the core-type composite fiber became 2.3 denier.

[0100] Comparative Example 7: Manufacturing of nonwoven fabric

[0101] A nonwoven fabric composed of side-by-side composite fibers (1) having the structure of Fig. 2 was manufactured by the following method. Specifically, 55 parts by weight of a first polypropylene (PP1) for forming side A and 45 parts by weight of a second polypropylene (PP2) for forming side B were melted by separate extruders to form a melt for forming side A and a melt for forming side B, respectively. Thereafter, each of the melts was discharged through a spinneret having a composite spinning nozzle. Thereafter, each of the discharged melts was cooled by cooling air and tension was applied by drawing air to have a fineness of 1.7 denier. Thereafter, the cooled and drawn composite fibers were collected on a collecting belt and deposited to a predetermined thickness to form a nonwoven fabric. Thereafter, mechanical properties were imparted to the formed nonwoven fabric by embossing using a heated embossing roll. As a result, a nonwoven fabric was obtained. At this time, the melt flow rate of the first polypropylene (PP1) for forming the side A, the melt flow rate of the second polypropylene (PP1) for forming the side B, the spinning speed, and the discharge amount per hole during spinning were adjusted so that the difference in crystal orientation (crystal orientation of the deep part - crystal orientation of the first part) was 1.5.

[0102] In the above Examples 1 to 7 and Comparative Examples 1 to 7, the weight ratio of the first polypropylene (PP1) and the second polypropylene (PP2), the fineness (denier) of the composite fiber, and the difference between the crystal orientation of the first polypropylene (PP1) and the crystal orientation of the second polypropylene (PP2) are shown in Table 1 below.

[0103] PP1 / PP2 Weight ratio determination Orientation difference Denier Example 155 / 45 1.5 1.7 Example 230 / 70 1.5 1.7 Example 380 / 201.5 1.7 Example 455 / 45 0.5 1.7 Example 555 / 45 2.5 1.7 Example 655 / 45 1.5 1.4 Example 755 / 45 1.5 2.0 Comparative Example 125 / 75 1.5 1.7 Comparative Example 285 / 151.5 1.7 Comparative Example 355 / 45 0.2 1.7 Comparative Example 455 / 45 3.0 1.7 Comparative Example 555 / 45 1.5 1.1 Comparative Example 655 / 45 1.5 2.3 Comparative Example 755 / 45 1.5 1.7

[0104]

[0105] Evaluation example: Evaluation of physical properties of nonwoven fabric

[0106] The physical properties of each nonwoven fabric manufactured in Examples 1 to 7 and Comparative Examples 1 to 7 were evaluated using the following method, and the results are shown in Table 2 below.

[0107] (1) Tensile strength: Using a tensile strength tester (Instron) measuring equipment, a tensile test was performed according to the KSK 0520 method under the conditions of a specimen width of 5 cm, spacing of 10 cm, and a tensile speed of 500 mm / min to obtain the maximum tensile load.

[0108] (2) Strength: According to the measurement standard WSP (Worldwide Strategic Partners) 90.1, 16 samples (25 mm × 150 mm) were collected in the MD and CD directions, placed on the strength measuring device, pushed in the direction of the slope until the specimen touched the slope, and the length of the sample from the bending point to the point where it touched the slope was measured in mm.

[0109] (3) Coefficient of friction: The coefficient of friction was measured using TOYOSEIKI HM-3 according to ASTM D 1894.

[0110] (4) Water pressure: Water pressure was measured using a water pressure measuring device (manufactured by TEXTEST, model number FX-3000-4M) in accordance with Worldwide Strategic Partners (hereinafter referred to as “WSP”) 80.6(09).

[0111] MD tensile strength (kgf / 5cm)CD tensile strength (kgf / 5cm)MD strength (mm)CD strength (mm)Friction coefficient (μ) S ) Water pressure (mmHg) Example 13.41.442350.2572 Example 23.81.643340.2475 Example 33.93.644350.2570 Example 43.11.541340.2566 Example 54.12.046350.2480 Example 63.61.545350.2275 Example 73.31.441320.2661 Comparative Example 12.81.256350.2570 Comparative Example 22.71.143360.2665 Comparative Example 32.91.045340.2459 Comparative Example 44.32.157520.4182Comparative Example 53.71.563540.2076Comparative Example 63.11.042320.4354Comparative Example 72.11.041330.2462

[0112]

[0113] Referring to Table 2 above, the nonwoven fabrics manufactured in Examples 1 to 7 were found to have excellent MD tensile strength, CD tensile strength, MD stiffness, CD stiffness, friction coefficient, and water pressure resistance, all of which are suitable for the purpose of the present invention.

[0114] On the other hand, the nonwoven fabrics manufactured in Comparative Examples 1 to 7 were found to have poor physical properties in at least one of MD tensile strength, CD tensile strength, MD stiffness, CD stiffness, friction coefficient, and water pressure resistance.

[0115] While the present invention has been described with reference to the drawings and examples, these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent implementations are possible. Therefore, the true scope of technical protection of the present invention should be determined by the technical spirit of the appended claims.

[0116] [Explanation of symbols]

[0117] 100: Core-type composite fiber 110: Core

[0118] 120: First part

Claims

1. Contains a core-type composite fiber in which the crystal orientation of the core is lower than that of the core, A nonwoven fabric having a difference in crystal orientation between the core and the superstructure of 0.5 to 2.

5.

2. In paragraph 1, The above-mentioned core-type composite fiber is a nonwoven fabric including a core having a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 20 to 80 g / 10 min as measured according to ASTM D1238 and a sheath having a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 35 to 115 g / 10 min as measured according to ASTM D1238.

3. In paragraph 2, The above-mentioned first part is a nonwoven fabric having a melt flow rate greater than that of the above-mentioned deep part by 15 to 35 g / 10 min.

4. In paragraph 1, A nonwoven fabric having a weight ratio of the core to the base of the fabric of 30 to 80:20 to 70.

5. In paragraph 1, A nonwoven fabric wherein the core comprises a first polypropylene and the upper portion comprises a second polypropylene.

6. In paragraph 1, The above-mentioned core-type composite fiber is a nonwoven fabric with a fineness of 1.4 to 2.0 denier.

7. In paragraph 1, A nonwoven fabric having an MD tensile strength of 3.0 to 4.5 kgf / 5 cm, a CD tensile strength of 1.2 to 2.4 kgf / 5 cm, an MD stiffness of 30 to 60 mm, a CD stiffness of 20 to 50 mm, a friction coefficient of 0.2 to 0.40 μs, and a water pressure resistance of 60 to 100 mmH2O.

8. In paragraph 1, The above nonwoven fabric is a spunbond nonwoven fabric.

9. In paragraph 1, The above nonwoven fabric is a nonwoven fabric composed of two or more layers.

10. An article containing a nonwoven fabric according to any one of paragraphs 1 to 9.

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