Highly absorbent composite fiber, highly absorbent nonwoven fabric, and article containing the nonwoven fabric

Abstract

Disclosed is a highly absorbent composite fiber, a highly absorbent non-woven fabric, and an article including the non-woven fabric. The disclosed highly absorbent composite fiber includes a core and a sheath, the core includes a polyolefin resin, and the sheath includes an ethylene-vinyl alcohol copolymer (EVOH, ethylene vinyl alcohol).

Description

Technical Field

[0001] Disclosed are a highly absorbent composite fiber, a highly absorbent nonwoven fabric, and an article including the nonwoven fabric. More specifically, disclosed are a highly absorbent composite fiber, a highly absorbent nonwoven fabric, and an article including the nonwoven fabric, which are excellent in absorbency and cold sensation. Background Art

[0002] Generally, nonwoven fabrics require various properties according to their intended uses.

[0003] For example, nonwoven fabrics applicable to sanitary materials and patch-type facial masks need to have excellent absorbency and cold sensation.

[0004] Accordingly, various methods have been proposed to endow nonwoven fabrics with excellent absorbency and cold sensation. A conventional method is to perform post-treatment with a hydrophilic oil agent after manufacturing the nonwoven fabric. However, the disadvantage of the above method is that when the nonwoven fabric continuously absorbs moisture, the oil agent is washed away, thereby causing the nonwoven fabric to lose its hydrophilicity and its absorbency to decrease.

[0005] For example, Korean Patent Publication No. 10-2106115 proposes a method of immersing a nonwoven fabric in a hydrophilic agent including a nonionic surfactant and then drying it after manufacturing the hydrophilic agent, but this method has a complicated process and low productivity, and there is a problem of decreased hydrophilicity when the nonwoven fabric continuously absorbs moisture.

[0006] [Prior Art Documents]

[0007] [Patent Documents]

[0008] (Patent Document 1) Korean Patent Publication No. 10-2106115 (Registration Date: Apr. 23, 2020) Summary of the Invention

[0009] Technical Problem

[0010] One embodiment of the present invention provides a highly absorbent composite fiber having excellent absorbency and cold sensation.

[0011] Another embodiment of the present invention provides a highly absorbent nonwoven fabric including the highly absorbent composite fiber.

[0012] Still another embodiment of the present invention provides an article including the highly absorbent nonwoven fabric.

[0013] Technical Solution

[0014] One aspect of the present invention provides a composite fiber including:

[0015] a core including a polyolefin resin; and

[0016] Sheath, which comprises ethylene-vinyl alcohol copolymer (EVOH, ethylene vinyl alcohol) and polyethylene glycol

[0017] (PEG, polyethylene glycol).

[0018] The weight ratio of the core to the sheath may be 50 to 90:10 to 50.

[0019] In the sheath, based on 100 parts by weight of the ethylene-vinyl alcohol copolymer (EVOH, ethylene vinyl alcohol), the content of the polyethylene glycol (PEG, polyethylene glycol) may be 1 part by weight to 10 parts by weight.

[0020] The melt index of the sheath may be 10 g / 10 min to 60 g / 10 min.

[0021] Based on 100 parts by weight of the EVOH resin, the sheath may further comprise 0.1 part by weight to 15 parts by weight of an inorganic additive.

[0022] On the other hand, the present invention provides a non-woven fabric

[0023] which comprises the composite fiber.

[0024] The water absorption rate of the non-woven fabric may be 550% to 1500%, and the thermal conductivity may be greater than or equal to

[0025] 0.1 W / m·K.

[0026] On the other hand, the present invention provides an article, which comprises:

[0027] the non-woven fabric.

[0028] The article may be a sanitary material or a patch-type facial mask.

[0029] Advantageous effects

[0030] The highly absorbent composite fiber, the highly absorbent non-woven fabric and the article according to the embodiments of the present invention may have excellent absorbency and cold-sensation. Description of the drawings

[0031] Figure 1 is a cross-sectional view of a highly absorbent composite fiber according to an embodiment of the present invention. Detailed description

[0032] Hereinafter, a highly absorbent composite fiber (hereinafter referred to as "composite fiber") according to an embodiment of the present invention will be described in detail.

[0033] A composite fiber according to an embodiment of the present invention includes a core and a sheath.

[0034] The core may include a polyolefin resin.

[0035] The polyolefin resin may include a homopolymer of propylene, a copolymer of propylene and various α-olefins, a homopolymer of ethylene, a copolymer of ethylene and various α-olefins, or a combination thereof.

[0036] In addition, the polyolefin resin may have hydrophobicity.

[0037] In addition, the core may not include ethylene-vinyl alcohol copolymer (EVOH) and polyethylene glycol (PEG).

[0038] In addition, since the core includes a hydrophobic olefin resin but does not include EVOH, when the composite fiber and the nonwoven fabric including the same are immersed in water, water is only absorbed by the surface of the composite fiber including EVOH, and water does not penetrate into the interior of the composite fiber, thereby preventing volume expansion of the core.

[0039] The sheath may include EVOH and PEG.

[0040] The EVOH is a copolymer of ethylene and vinyl alcohol, and has hydrophilicity due to the inclusion of hydroxyl groups (OH), so it can absorb water well. Moreover, the less the ethylene content, the more the hydroxyl groups, thereby improving the water absorption rate.

[0041] In addition, the thermal conductivity of the EVOH is 0.3 W / m·K to 0.4 W / m·K, which is more than twice the thermal conductivity of polypropylene (PP) as an olefin resin, which is 0.1 W / m·K to 0.15 W / m·K.

[0042] Heat conduction refers to the movement of heat from a high-temperature part to a low-temperature part inside a substance. When EVOH with high thermal conductivity comes into contact with human skin, the heat of the human body moves more easily to the EVOH, so it exhibits a cold feeling that provides a cool feeling.

[0043] In addition, the melt index (MI: measurement temperature 210 °C, load 2.16 kg) of the EVOH measured according to ASTM D1238 may be 10 g / 10 min to 60 g / 10 min. When the melt index of the EVOH is less than 10

[0044] g / 10 min, the nozzle pressure suddenly rises due to too high viscosity, so it cannot be produced for a long time. When it is greater than 60

[0045] g / 10 min, it is difficult to form a composite fiber structure due to too low viscosity.

[0046] In addition, the melting temperature (Tm) of the EVOH may be 155°C to 185°C.

[0047] When the PEG is present in the core as a hydrophilic component, the water absorption rate of the nonwoven fabric including the composite fiber can be increased, and a continuous cooling effect can be provided due to its high latent heat.

[0048] In the sheath, based on 100 parts by weight of the EVOH, the content of the PEG may be 1 part by weight to 10 parts by weight. When the content of the PEG is less than 1 part by weight based on 100 parts by weight of the EVOH, a higher water absorption rate can be achieved than when the EVOH exists alone, while when it is greater than 10 parts by weight, fiber breakage may occur due to deteriorated spinnability.

[0049] Based on 100 parts by weight of the EVOH resin, the sheath may further include 0.1 part by weight to 15 parts by weight of an inorganic additive. When the content of the inorganic additive is less than 0.1 part by weight based on 100 parts by weight of the EVOH, the addition effect is not significant, while when it is greater than 15 parts by weight, uneven distribution and breakage may occur due to decreased dispersibility.

[0050] The inorganic additive is used to further improve the cooling effect of the nonwoven fabric including the composite fiber.

[0051] The thermal conductivity of the inorganic additive may be greater than or equal to 0.5 W / m·K. When the thermal conductivity of the inorganic additive is less than 0.5 W / m·K, a sufficient cooling effect cannot be provided.

[0052] In addition, the inorganic additive may include titanium dioxide (TiO2), calcium carbonate (CaCO3), zinc oxide

[0053] (ZnO), aluminum oxide (Al2O3), graphene, or a combination thereof.

[0054] The weight ratio of the core to the sheath may be 50 to 90:10 to 50. When the weight ratio of the sheath is less than 10,

[0055] a high water absorption rate and a cooling effect cannot be obtained, while when the weight ratio of the sheath is greater than 50, fiber spinning cannot be performed.

[0056] On the other hand, the present invention provides a highly absorbent nonwoven fabric (hereinafter referred to as "nonwoven fabric") including the composite fiber.

[0057] The nonwoven fabric may have a water absorption rate (W f ) represented by the following Mathematical Formula 1 of 550% to 1500%.

[0058]

Mathematical Formula 1

[0059]

[0060] Among them, W a is the weight of the non-woven fabric sample after absorbing moisture, and W b is the weight of the non-woven fabric sample before absorbing moisture.

[0061] In addition, the thermal conductivity of the non-woven fabric can be greater than or equal to 0.1 W / m·K.

[0062] On the other hand, the present invention provides an article comprising the non-woven fabric.

[0063] The article can be a sanitary material or a patch-type facial mask.

[0064] Hereinafter, the present invention will be further described in detail by way of examples. These examples are intended to further describe the present invention in detail, and the scope of the present invention is not limited thereto.

[0065] The present invention will be further described in detail by way of examples. The scope of the present invention is not limited thereto.

[0066] Comparative Example 1: Manufacturing Composite Fibers and Nonwoven Fabrics

[0067] Polypropylene is used for the core, and EVOH with a melting point of 171 °C and a melt index of 50 g / 10 min (measured at 210 °C and a load of 2.16 kg) is used for the sheath. The temperature of the extruder for melting the resin is 220 °C. In the molten resin, with the help of the distribution plate in the composite spinning nozzle, the polypropylene is moved to the core and the EVOH is moved to

[0068] the sheath, and then spun out through the nozzle at a speed of 2500 mpm in a composite cross-section form to form composite fibers. Then, the composite fibers are opened to form a web, and a non-woven fabric is manufactured by calendering. Based on weight, the core:sheath ratio of the formed filaments is 70:30.

[0069] Example 1: Manufacturing Composite Fibers and Nonwoven Fabrics

[0070] Except that 5 parts by weight of PEG is added to 100 parts by weight of the EVOH resin in the sheath, composite fibers and a non-woven fabric are manufactured by the same method as in Comparative Example 1.

[0071] Example 2: Manufacturing Composite Fibers and Nonwoven Fabrics

[0072] Except that 5 parts by weight of PEG is added to 100 parts by weight of the EVOH resin in the sheath and the weight ratio of the core:sheath is changed to 50:50, composite fibers and a non-woven fabric are manufactured by the same method as in Comparative Example 1.

[0073] Example 3: Manufacturing Composite Fibers and Nonwoven Fabrics

[0074] Except that 5 parts by weight of PEG was added to 100 parts by weight of EVOH resin in the sheath and the core:sheath weight ratio was changed to 90:10, the composite fibers and nonwoven fabrics were manufactured by the same method as in Comparative Example 1.

[0075] Example 4: Manufacturing Composite Fibers and Nonwoven Fabrics

[0076] Except that 1 part by weight of PEG was added to 100 parts by weight of EVOH resin in the sheath, the composite fibers and nonwoven fabrics were manufactured by the same method as in Comparative Example 1.

[0077] Example 5: Manufacturing Composite Fibers and Nonwoven Fabrics

[0078] Except that 10 parts by weight of PEG was added to 100 parts by weight of EVOH resin in the sheath, the composite fibers and nonwoven fabrics were manufactured by the same method as in Comparative Example 1.

[0079] Comparative Example 2: Manufacturing Composite Fibers and Nonwoven Fabrics

[0080] Except that 7 parts by weight of calcium carbonate (CaCO3) as an inorganic additive with a thermal conductivity of 2.5 W / m·K was added to 100 parts by weight of EVOH resin in the sheath, the composite fibers and nonwoven fabrics were manufactured by the same method as in Comparative Example 1.

[0081] Comparative Example 3: Manufacturing Composite Fibers and Nonwoven Fabrics

[0082] Except that 7 parts by weight of calcium carbonate (CaCO3) as an inorganic additive with a thermal conductivity of 2.5 W / m·K was added to 100 parts by weight of EVOH resin in the sheath and the core:sheath weight ratio was changed to 50:50, the composite fibers and nonwoven fabrics were manufactured by the same method as in Comparative Example 1.

[0083] Comparative Example 4: Manufacturing Composite Fibers and Nonwoven Fabrics

[0084] Except that 15 parts by weight of calcium carbonate (CaCO3) as an inorganic additive with a thermal conductivity of 2.5 W / m·K was added to 100 parts by weight of EVOH resin in the sheath, the composite fibers and nonwoven fabrics were manufactured by the same method as in Comparative Example 1.

[0085] Example 6: Manufacturing Composite Fibers and Nonwoven Fabrics

[0086] Except that 5 parts by weight of PEG and 7 parts by weight of calcium carbonate (CaCO3) as an inorganic additive with a thermal conductivity of 2.5 W / m·K were added to 100 parts by weight of EVOH resin in the sheath, the composite fibers and nonwoven fabrics were manufactured by the same method as in Comparative Example 1.

[0087] Example 7: Manufacturing Composite Fibers and Nonwoven Fabrics

[0088] Except that 5 parts by weight of PEG and 7 parts by weight of calcium carbonate (CaCO3) as an inorganic additive with a thermal conductivity of 2.5 W / m·K were added to 100 parts by weight of the EVOH resin in the sheath, and the core:sheath weight ratio was changed to 50:50, the composite fibers and non-woven fabrics were produced by the same method as in Comparative Example 1.

[0089] Comparative Example 5: Manufacturing Composite Fibers and Nonwoven Fabrics

[0090] Except that 5 parts by weight of PEG was added to 100 parts by weight of the EVOH resin in the sheath, and the core:sheath weight ratio was changed to 45:55, the composite fibers and non-woven fabrics were produced by the same method as in Comparative Example 1.

[0091] Comparative Example 6: Manufacturing Composite Fibers and Nonwoven Fabrics

[0092] Except that 5 parts by weight of PEG was added to 100 parts by weight of the EVOH resin in the sheath, and the core:sheath weight ratio was changed to 95:5, the composite fibers and non-woven fabrics were produced by the same method as in Comparative Example 1.

[0093] Comparative Example 7: Manufacturing Composite Fibers and Nonwoven Fabrics

[0094] Except that 0.5 part by weight of PEG was added to 100 parts by weight of the EVOH resin in the sheath, the composite fibers and non-woven fabrics were produced by the same method as in Comparative Example 1.

[0095] Comparative Example 8: Manufacturing Composite Fibers and Nonwoven Fabrics

[0096] Except that 12 parts by weight of PEG was added to 100 parts by weight of the EVOH resin in the sheath, the composite fibers and non-woven fabrics were produced by the same method as in Comparative Example 1.

[0097] Comparative Example 9: Manufacturing Composite Fibers and Nonwoven Fabrics

[0098] Except that 7 parts by weight of calcium carbonate (CaCO3) as an inorganic additive with a thermal conductivity of 2.5 W / m·K was added to 100 parts by weight of the EVOH resin in the sheath, and the core:sheath weight ratio was changed to 45:55, the composite fibers and non-woven fabrics were produced by the same method as in Comparative Example 1.

[0099] Comparative Example 10: Manufacturing Composite Fibers and Nonwoven Fabrics

[0100] Except that 7 parts by weight of calcium carbonate (CaCO3) as an inorganic additive with a thermal conductivity of 2.5 W / m·K was added to 100 parts by weight of the EVOH resin in the sheath, and the core:sheath weight ratio was changed to 95:5, the composite fibers and non-woven fabrics were produced by the same method as in Comparative Example 1.

[0101] Comparative Example 11: Manufacturing Composite Fibers and Nonwoven Fabrics

[0102] Except for adding 17 parts by weight of calcium carbonate (CaCO3), which is an inorganic additive with a thermal conductivity of 2.5 W / m·K, based on 100 parts by weight of the EVOH resin in the sheath, the composite fibers and nonwoven fabrics were manufactured by the same method as in Comparative Example 1.

[0103] Comparative Example 12: Manufacturing Composite Fibers and Nonwoven Fabrics

[0104] Except for adding 0.5 part by weight of PEG and 0.05 part by weight of calcium carbonate (CaCO3), which is an inorganic additive with a thermal conductivity of 2.5 W / m·K, based on 100 parts by weight of the EVOH resin in the sheath, the composite fibers and nonwoven fabrics were manufactured by the same method as in Comparative Example 1.

[0105] Comparative Example 13: Manufacturing Composite Fibers and Nonwoven Fabrics

[0106] Except for adding 12 parts by weight of PEG and 17 parts by weight of calcium carbonate (CaCO3), which is an inorganic additive with a thermal conductivity of 2.5 W / m·K, based on 100 parts by weight of the EVOH resin in the sheath, the composite fibers and nonwoven fabrics were manufactured by the same method as in Comparative Example 1.

[0107] Comparative Example 14: Manufacturing Composite Fibers and Nonwoven Fabrics

[0108] Except for changing the weight ratio of core:sheath to 100:0, the composite fibers and nonwoven fabrics were manufactured by the same method as in Comparative Example 1.

[0109] Evaluation Example

[0110] After evaluating the water absorption rate according to the above mathematical formula 1 and evaluating the thermal conductivity, the results are shown in Table 1 below.

[0111] Table 1

[0112]

[0113] Referring to Table 1 above, the nonwoven fabrics manufactured by Examples 1 to 7 are excellent in both water absorption rate (≥550%) and thermal conductivity (≥0.1 W / m·K).

[0114] In contrast, the nonwoven fabrics manufactured by Comparative Examples 1 to 4, 6 to 7, 10, 12, and 14

[0115] (≥0.1 W / m·K) are excellent in thermal conductivity, but have a low water absorption rate (<550%).

[0116] In addition, in Comparative Examples 5, 8 to 9, 11, and 13, nonwoven fabrics could not be manufactured due to the inability to spin, and thus the thermal conductivity and water absorption rate could not be measured.

[0117] Although the present invention has been described with reference to the accompanying drawings and embodiments, this is merely exemplary, and those skilled in the art can understand that various modifications and equivalent other embodiments can be made therefrom. Therefore, the true technical protection scope of the present invention should be determined by the technical concept of the appended claims.

Claims

1. A non-woven fabric comprising composite fibers, the composite fibers comprising: a core comprising a polyolefin resin; and a sheath comprising ethylene-vinyl alcohol copolymer (EVOH) and PEG (polyethylene glycol), wherein the core does not comprise ethylene-vinyl alcohol copolymer (EVOH) and PEG (polyethylene glycol), wherein in the sheath, the content of the PEG is 1 to 10 parts by weight based on 100 parts by weight of the EVOH, wherein the weight ratio of the core to the sheath is 50 to 90:10 to 50.

2. The non-woven fabric according to claim 1, wherein, The melt index of the sheath is 10 g / 10min to 60 g / 10min.

3. The non-woven fabric according to claim 1, wherein, The water absorption rate of the non-woven fabric is 550% to 1500%, and the thermal conductivity is greater than or equal to 0.1 W / m·K.

4. An article, comprising: The non-woven fabric according to any one of claims 1-3.

5. The article according to claim 4, wherein The article is a sanitary material or a patch-type facial mask.

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