Nonwoven fabric, method for manufacturing the nonwoven fabric, and articles thereof

Abstract

A nonwoven fabric, a method for making the nonwoven fabric, and an article thereof are disclosed. The nonwoven fabric disclosed has a 100 sec. -1 The melt viscosity measured at a shear rate of 1000 to 740 poise at a temperature of 230°C.

Description

[Technical Field]

[0001] The present invention relates to a nonwoven fabric, a method for producing the nonwoven fabric, and articles thereof, and more particularly to a nonwoven fabric that is excellent in both bonding properties and strength, a method for producing the nonwoven fabric, and articles thereof. [Background technology]

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

[0003] Furthermore, nonwoven fabrics are generally manufactured and used in a multilayer structure with two or more layers bonded together, and in most applications, they are required to have excellent strength. Therefore, many researchers are currently engrossed in developing multilayer nonwoven fabrics with superior strength.

[0004] Furthermore, recent trends have led to a pursuit of lower weight in existing nonwoven fabrics, but maintaining the existing physical properties of the nonwoven fabrics, or even improving them by adding to them, has presented process and equipment limitations. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] One embodiment of the present invention provides a nonwoven fabric that is excellent in both bonding properties and strength. Another embodiment of the present invention provides a method for producing the nonwoven fabric. A further embodiment of the present invention provides an article comprising the nonwoven fabric. [Means for solving the problem]

[0006] One aspect of the present invention is, 100 sec according to ASTM D4440-08 -1 The present invention provides a nonwoven fabric having a shear rate and a melt viscosity measured at a temperature of 230°C of 500 to 740 poise.

[0007] The nonwoven fabric also contains core-sheath type composite fibers, which include a core portion with a melting index (MFR (measurement temperature 230°C, load 2.16 kg)) of 20-50 g / 10 min as measured by ASTM D1238, and a sheath portion with a melting index (MFR (measurement temperature 230°C, load 2.16 kg)) of 40-120 g / 10 min as measured by ASTM D1238.

[0008] The melting index of the sheath portion may be about 10 to 100 g / 10 min higher than that of the core portion.

[0009] The weight ratio of the sheath portion to the core portion is also 1-5:9-5.

[0010] The core portion may also contain a first polypropylene, and the sheath portion may also contain a second polypropylene.

[0011] The aforementioned nonwoven fabric also has a toughness of 100 to 300, as expressed by the following formula 1:

number

[0012] The aforementioned nonwoven fabric is also a spunbond nonwoven fabric.

[0013] The aforementioned nonwoven fabric may also consist of two or more layers.

[0014] Other aspects of the present invention include: Step (S10): Melting the polymer for forming the core and the polymer for forming the sheath separately in different extruders to form the molten core and the molten sheath. The steps include: discharging each of the molten materials through a spinneret having a composite spinning nozzle to release composite long fibers (S20); The aforementioned released composite long fibers are cooled and stretched (S30), Collecting the cooled and drawn composite long fibers on a collecting belt, depositing them to a predetermined thickness, and forming a non-woven fabric (step S40). In the step (S20), there is provided a method for manufacturing a non-woven fabric in which the temperature of the spinneret is maintained at 230 to 250 °C.

[0015] The method for manufacturing the non-woven fabric may further include a step (S50) of imparting mechanical physical properties to the non-woven fabric formed in the step (S40).

[0016] Still another aspect of the present invention provides an article including the non-woven fabric.

Advantages of the Invention

[0017] The non-woven fabric according to an embodiment of the present invention, and an article including the same, both have advantages of excellent bonding property and strength.

Brief Description of the Drawings

[0018] [Figure 1] It is a cross-sectional view of a core-sheath type composite fiber constituting a non-woven fabric according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view of a side-by-side type composite fiber constituting a non-woven fabric according to Comparative Example 11.

Modes for Carrying Out the Invention

[0019] Hereinafter, a non-woven fabric according to an embodiment of the present invention will be described in detail.

[0020] The non-woven fabric according to an embodiment of the present invention also has a melt viscosity measured at a shear rate of 100 sec -1 and a temperature of 230 °C according to ASTM D4440-08, which is 500 to 740 poises.

[0021] If the melt viscosity of the non-woven fabric is within the above range, the non-woven fabric may have excellent bonding property and strength.

[0022] Furthermore, if the melt viscosity of the nonwoven fabric is less than 500 poise, the strength of the individual fibers constituting the nonwoven fabric will decrease, and the strength of the nonwoven fabric will also decrease. Also, if the melt viscosity of the nonwoven fabric exceeds 740 poise, the bonding properties of the individual fibers constituting the nonwoven fabric will decrease, weakening the bonding force between the individual fibers, and consequently, the strength of the nonwoven fabric manufactured by laminating the individual fibers will also decrease.

[0023] The melt viscosity of the nonwoven fabric can be determined by the structure of the fibers constituting the nonwoven fabric, the type of raw materials constituting the fibers, the ratio and physical properties of the raw materials, the manufacturing conditions and method of the fibers, and the manufacturing conditions and method of the nonwoven fabric using the fibers.

[0024] The aforementioned nonwoven fabric also contains core-sheath type composite fibers.

[0025] The aforementioned core-sheath composite fiber also includes a core portion with a melting index (MFR (measurement temperature 230°C, load 2.16 kg)) of 20-50 g / 10 min as measured by ASTM D1238, and a sheath portion with a melting index (MFR (measurement temperature 230°C, load 2.16 kg)) of 40-120 g / 10 min as measured by ASTM D1238. If the melting index (MFR) of the core portion and the melting index (MFR) of the sheath portion are within the aforementioned ranges, then according to ASTM D4440-08, 100 sec -1 A nonwoven fabric can be obtained with a toughness of 100 to 300 at a shear rate and melt viscosity measured at a temperature of 230°C of 500 to 740 poise.

[0026] Furthermore, the melting rate (MFR) of the sheath portion may be 10 to 100 g / 10 min higher than that of the core portion. If the melting rate (MFR) of the sheath portion is within the range compared to that of the core portion, then according to ASTM D4440-08, 100 sec -1A nonwoven fabric can be obtained with a toughness of 100 to 300 at a shear rate and melt viscosity measured at a temperature of 230°C of 500 to 740 poise.

[0027] The weight ratio of the sheath to the core is also 1 to 5:9 to 5. If the weight ratio of the sheath to the core is within the above range, then 100 sec according to ASTM D4440-08 -1 A nonwoven fabric can be obtained with a toughness of 100 to 300 at a shear rate and melt viscosity measured at a temperature of 230°C of 500 to 740 poise.

[0028] Furthermore, the core portion contains a first polypropylene, and the sheath portion contains a second polypropylene.

[0029] The first propylene polymer and the second propylene polymer were also produced using a highly stereoregular polymerization catalyst.

[0030] The aforementioned highly stereoregular polymerization catalyst may also include a diester component catalyst, a succinate component catalyst, a metallocene catalyst, or a combination thereof.

[0031] Figure 1 is a cross-sectional view of a core-sheath type composite fiber 100 constituting a nonwoven fabric according to one embodiment of the present invention.

[0032] Referring to Figure 1, the core-sheath type composite fiber 100 also includes a core portion 110 and a sheath portion 120 configured to surround it.

[0033] The aforementioned nonwoven fabric also has a toughness of 100 to 300, as expressed by the following formula 1:

number

[0034] The aforementioned nonwoven fabric is also a spunbond nonwoven fabric.

[0035] The nonwoven fabric may also consist of two or more layers. For example, the nonwoven fabric may also be a nonwoven fabric laminate.

[0036] The fineness and basic weight of the nonwoven fabric can be appropriately selected depending on the application, but typically the fineness is 1.0 to 2.5 denier, for example, 0.7 to 2.0 denier, and the basic weight is 15 to 100 g / m². 2 For example, 7-30 g / m 2 But so.

[0037] The core-sheath composite fiber may, in addition to the first propylene polymer and the second propylene polymer, further contain additives as necessary, to the extent that it does not impair the objectives of the present invention. The additives may include known heat stabilizers, weather stabilizers, various stabilizers, antistatic agents, antiblocking agents, anticlouding agents, fillers, dyes, pigments, natural oils, synthetic oils, waxes, or combinations thereof.

[0038] The stabilizers may also 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)alkyl propionate, 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.

[0039] The filler may also include silica, diatomaceous earth, alumina, titanium oxide, magnesium oxide, pumice powder, pumice balloons, 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.

[0040] The aforementioned propylene polymer and the additives used as needed can be mixed using known methods.

[0041] The following describes in detail a method for manufacturing a nonwoven fabric according to one embodiment of the present invention.

[0042] A method for manufacturing a nonwoven fabric according to one embodiment of the present invention includes the steps of: melting a core-forming polymer and a sheath-forming polymer in separate extruders to form a core-forming molten material and a sheath-forming molten material (S10); extruding each of the molten materials through a spinneret having a composite spinning nozzle configured to extrude in a desired fiber structure to release composite long fibers (S20); cooling and stretching the released composite long fibers (S30); and collecting the cooled and stretched composite long fibers on a collection belt and depositing them to a predetermined thickness to form a nonwoven fabric (S40).

[0043] In step (S20), the temperature of the spinneret can be maintained at 230-250°C. In step (S20), if the temperature of the spinneret is within the range, 100 sec according to ASTM D4440-08 - A nonwoven fabric with a toughness of 100 to 300 can be obtained at a shear rate of 1 and a melt viscosity measured at a temperature of 230°C of 500 to 740 poise, and good process stability (spinability) can be obtained in the nonwoven fabric manufacturing process.

[0044] The aforementioned step (S30) is also a step in which the composite long fibers released in step (S20) are cooled with cooling air and tension is applied with stretching air to give them a predetermined fineness.

[0045] Furthermore, the method for manufacturing the nonwoven fabric also further includes a step (S50) of imparting mechanical properties to the nonwoven fabric formed in step (S40).

[0046] The aforementioned step (S50) can be carried out as a contangle treatment by means of needle punching, water jetting, ultrasonic waves, etc.; by embossing using a heated embossing roll, or by thermal fusion using high-temperature ventilation.

[0047] The following describes in detail an article according to one embodiment of the present invention.

[0048] An article according to one embodiment of the present invention includes the aforementioned nonwoven fabric.

[0049] The aforementioned items may also be diapers, absorbent products, defecation products, support layers, top sheets, medical clothing, protective clothing, or masks.

[0050] The present invention will be described in more detail below through the examples provided. These examples are intended to provide a more specific explanation of the present invention, but the scope of the present invention is not limited to these examples. [Examples]

[0051] Examples 1-11 and Comparative Examples 1-10: Manufacturing of Nonwoven Fabrics A nonwoven fabric made of core-sheath type composite fibers 100 having the structure shown in Figure 1 was manufactured by the following method. Specifically, a first polypropylene for forming the core and a second polypropylene for forming the sheath were melted in separate extruders to form the core-forming molten material and the sheath-forming molten material. Then, each of the molten materials was extruded through a spinneret having a composite spinning nozzle. After that, each of the extruded molten materials was cooled with cooling air, and tension was applied with stretching air to give it a predetermined fineness. Then, the cooled and stretched composite long fibers were collected on a collection belt and deposited to a predetermined thickness to form a nonwoven fabric. After that, mechanical properties were imparted to the formed nonwoven fabric by embossing using a heated embossing roll.

[0052] Furthermore, the melting index (MFR) of the first polypropylene for forming the core, the melting index (MFR) of the second propylene for forming the sheath, the difference in melting index (MFR) between the second propylene and the first propylene, and the weight ratio of the sheath to the core are shown in Table 1 below. In Table 1 below, "manufacturing temperature of the nonwoven fabric" refers to the temperature of the spinneret.

[0053] Comparative Example 11: Manufacturing of Nonwoven Fabric A nonwoven fabric made of side-by-side composite fibers (1) having the structure shown in Figure 2 was manufactured by the following method. Specifically, a first polypropylene for forming side A and a second polypropylene for forming side B were melted in separate extruders to form molten material for side A and molten material for side B. Then, each of the molten materials was extruded through a spinneret having a composite spinning nozzle. After that, each of the extruded molten materials was cooled with cooling air, and tension was applied with stretching air to give it a predetermined fineness. Then, the cooled and stretched composite long fibers were collected on a collection belt and deposited to a predetermined thickness to form a nonwoven fabric. After that, mechanical properties were imparted to the formed nonwoven fabric by embossing using a heated embossing roll.

[0054] Also, the melt flow rate (MFR) of the first polypropylene for forming side A, the melt flow rate (MFR) of the second propylene for forming side B, the difference in melt flow rate (MFR) between the second propylene and the first propylene, and the weight ratio of side A to side B are shown in Table 1 below. In Table 1 below, "manufacturing temperature of the non-woven fabric" means the temperature of the spinneret.

[0055] [Table 1]

[0056] Evaluation example: Physical property evaluation of nonwoven fabrics The physical properties of the non-woven fabrics produced in Examples 1 to 11 and Comparative Examples 1 to 11 were evaluated by the following methods, and the results are shown in Table 2 below. (1) Melt viscosity: The melt viscosity of the non-woven fabric at a shear rate of 100 sec -1 and a temperature of 230 °C was measured according to ASTM D4440-08. (2) Tensile strength: Using a tensile tensile strength and elongation tester (Instron) measurement facility, a tensile test was conducted according to the KSK 0520 method under the conditions of a test piece width of 5 cm, a spacing of 10 cm, and a tensile speed of 500 mm / min to obtain the maximum tensile load. (3) Tensile elongation: The elongation at the maximum elongation measured by the method in (3) above was obtained. (4) Basis weight (weight: g / m 2 ): Measured according to ASTM D3776-1985. (5) Toughness: Using the tensile strength (N / 5 cm) obtained in (2) above and the tensile elongation (%) obtained in (3) above, the toughness was determined by the following formula 1. [Equation] (6) Process stability (spinnability): During melt spinning, filament vibration was observed visually, and polymer drip was detected with a defect detector.

[0057] [Table 2]

[0058] Referring to Table 2 above, it can be seen that the nonwoven fabrics produced in Examples 1 to 10 not only have a melt viscosity in the range of 500 to 740 poise and a toughness in the range of 100 to 300, but also exhibit excellent MD tensile strength and MD tensile elongation. Furthermore, it can be seen that the nonwoven fabric manufacturing processes in Examples 1 to 10 exhibit excellent process stability (spinability).

[0059] On the other hand, the nonwoven fabrics produced in Comparative Examples 1 to 11 have a melt viscosity outside the range of 500 to 740 poise, and a toughness outside the range of 100 to 300. Furthermore, the nonwoven fabric manufacturing processes in Comparative Examples 1 to 3 exhibit poor process stability (spinability).

[0060] Although the present invention has been described with reference to the drawings and embodiments, these are merely illustrative, and a person with ordinary skill in the art will understand from them that a variety of modifications and equivalent other embodiments are possible. Accordingly, the true scope of technical protection of the present invention is determined by the technical idea of ​​the claims.

Claims

1. According to ASTM D4440-08, 100 sec －１ A nonwoven fabric having a shear rate and a melt viscosity measured at a temperature of 230°C of 500 to 740 poise, The nonwoven fabric contains core-sheath type composite fibers. The core of the core-sheath type composite fiber contains primary polypropylene and has a melt index (MFR (measurement temperature 230°C, load 2.16 kg)) of 20 to 50 g / 10 min as measured by ASTM D1238, and the sheath of the core-sheath type composite fiber contains secondary polypropylene and has a melt index (MFR (measurement temperature 230°C, load 2.16 kg)) of 40 to 120 g / 10 min as measured by ASTM D1238. Nonwoven fabrics with a toughness of 100 to 300, as expressed by the following formula 1: [Math 1]

2. The nonwoven fabric according to claim 1, wherein the sheath portion has a melting index (MFR) that is about 10 to 100 g / 10 min higher than that of the core portion.

3. The nonwoven fabric according to claim 1, wherein the weight ratio of the sheath portion to the core portion is 1 to 5:9 to 5.

4. The nonwoven fabric according to claim 1, wherein the nonwoven fabric is a spunbond nonwoven fabric.

5. The nonwoven fabric according to claim 1, wherein the nonwoven fabric comprises two or more layers.

6. An article comprising a nonwoven fabric as described in any one of claims 1 to 5.

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