US20230257912A1

US20230257912A1 - Highly absorbent composite fibre, highly absorbent non-woven fabric, and article comprising same

Info

Publication number: US20230257912A1
Application number: US18/134,764
Authority: US
Inventors: Man Jae HAN; Geung Sik Jeong
Original assignee: Toray Advanced Materials Korea Inc
Current assignee: Toray Advanced Materials Korea Inc
Priority date: 2020-10-16
Filing date: 2023-04-14
Publication date: 2023-08-17
Also published as: CN116507765A; CN116507765B; JP7634655B2; KR102420139B1; WO2022080953A1; KR20220050675A; JP2023540764A

Abstract

Disclosed are 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 including a polyolefin-based resin; and a sheath including ethylene vinyl alcohol (EVOH) resin.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No. PCT/KR2021/014368, filed on Oct. 15, 2021, which claims priority to, and the benefit of Korean Patent Application No. 10-2020-0134626 filed on Oct. 16, 2020. The disclosures of the above applications are incorporated herein by reference.

FIELD

The present disclosure relates to a highly absorbent composite fiber, a highly absorbent non-woven fabric, and an article including the non-woven fabric. More specifically, the present disclosure relates to a highly absorbent composite fiber, a highly absorbent non-woven fabric, and an article including the non-woven fabric, having excellent absorbency and cool feeling performance.

BACKGROUND

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
In general, non-woven fabrics are required to have various properties depending on their application.
For example, non-woven fabrics applied to sanitary materials and cosmetic mask packs require excellent absorbency and cool feeling.
Accordingly, various methods for imparting excellent absorbency and cool feeling to non-woven fabrics have been proposed, and a method of post-processing with a hydrophilic emulsion after preparation of non-woven fabrics is commonly used. However, the method as described above has a disadvantage in that when the non-woven fabric continuously absorbs moisture, the emulsion is washed away, and thus the non-woven fabric loses hydrophilicity and the absorption performance is also reduced.
For example, Korean Patent Registration No. 10-2106115 proposed a method of preparing a hydrophilic agent including a nonionic surfactant, and immersing a non-woven fabric in the hydrophilic agent and then drying the same, but there are issues of complicatedness of the processes, low productivity, and loss of hydrophilicity when the non-woven fabric continuously absorbs moisture.
Prior Art Literature: Korean Patent Registration No. 10-2106115 (registration date 2020 Apr. 23)

SUMMARY

This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all of its features.
An embodiment of the present disclosure provides a highly absorbent composite fiber, having excellent absorbency and cool feeling performance.
Another embodiment of the present disclosure provides a highly absorbent non-woven fabric including the highly absorbent composite fiber.
Still another embodiment of the present disclosure provides an article including the highly absorbent non-woven fabric.
An aspect of the present disclosure provides: a composite fiber including: a core including a polyolefin-based resin; and a sheath including an ethylene vinyl alcohol (EVOH) resin, and a polyethylene glycol (PEG).
A weight ratio of the core to the sheath may be 50 to 90:10 to 50.
An amount of the PEG in the sheath may be 1 part by weight to 10 parts by weight, with respect to 100 parts by weight of the EVOH resin.
A melting index of the sheath may be about 10 g/10 min to about 60 g/10 min.
The sheath may further include about 0.1 part by weight to about 15 parts by weight of an inorganic additive, with respect to 100 parts by weight of the EVOH resin.
Another aspect of the present disclosure provides a non-woven fabric including the composite fiber.
The non-woven fabric may have a moisture absorption rate of about 550% to about 1,500% and a thermal conductivity of about 0.1 W/m·K or more.
Still another aspect of the present disclosure provides an article including the non-woven fabric.
The article may be a sanitary material or a cosmetic mask pack.
A highly absorbent composite fiber, a highly absorbent non-woven fabric, and an article according to embodiments of the present disclosure may have excellent absorbency and cool feeling performance.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

FIG. 1 is a cross-sectional view of a highly absorbent composite fiber according to an embodiment of the present disclosure.

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
Hereinafter, a highly absorbent composite fiber (hereinafter simply referred to as a “composite fiber”) according to an embodiment of the present disclosure will be described in detail.
A composite fiber according to an embodiment of the present disclosure includes a core and a sheath.
The core may include a polyolefin-based resin.
The polyolefin-based 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.
In addition, the polyolefin-based resin may be hydrophobic.
In addition, the core may not include an ethylene vinyl alcohol (EVOH) resin and a polyethylene glycol (PEG).
In addition, since the core includes a hydrophobic olefin-based resin but does not include the EVOH resin, when the composite fiber and the non-woven fabric including the composite fiber are immersed in water, water is absorbed only on the surface of the composite fiber including the EVOH resin, and does not permeate into the interior of the composite fiber, and thus, it is possible to prevent the core from expanding in volume.
The sheath may include the EVOH resin and the PEG.
The EVOH resin is a copolymer of ethylene and vinyl alcohol, and have hydrophilicity due to hydroxyl groups (OHs) included therein, and therefore, the EVOH may absorb water well, and the smaller the ethylene content, the more hydroxyl groups the EVOH resin has, which may increase a moisture absorption rate.
In addition, the EVOH resin has a thermal conductivity of about 0.3 W/m·K to about 0.4 W/m·K, which is more than twice as high as the thermal conductivity of polypropylene (PP), which is an olefin resin, of about 0.1 W/m·K to about 0.15 W/m·K. Thermal conduction refers to movement of heat from a place with a high temperature to a place with a low temperature within a material. When the EVOH resin with a high thermal conductivity comes into contact with human skin, heat from the human body is more easily transferred to the EVOH resin, and cool feeling of the EVOH resin that gives a cooling sensation may be exhibited.
In addition, the EVOH resin may have a melting index (MI: measurement temperature 210° C., load 2.16 kg) of about 10 g/10 min to about 60 g/10 min measured according to ASTM D1238. When a melting index of the EVOH resin is less than 10 g/10 min, viscosity thereof is too high and a nozzle pressure rapidly rises, making long-term production impossible, and when a melting index of the EVOH resin is higher than 60 g/10 min, viscosity thereof is too low and it is hard to form a composite fiber structure.
In addition, the EVOH resin may have a melting temperature (Tm) of 155° C. to 185° C.
When the PEG is present in the sheath as a hydrophilic component, the PEG may improve a moisture absorption rate of a non-woven fabric including the composite fiber and provide a continuous cooling effect due to its high latent heat.
An amount of the PEG in the sheath may be about 1 part by weight to about 10 parts by weight, with respect to 100 parts by weight of the EVOH resin. When an amount of the PEG is less than about 1 part by weight, with respect to 100 parts by weight of the EVOH resin, a higher moisture absorption rate than that of the EVOH resin alone may not be realized, and when an amount of the PEG exceeds 10 parts by weight, with respect to 100 parts by weight of the EVOH resin, spinnability becomes poor, which may lead to breakage of the fiber.
The sheath may further include 0.1 part by weight to 15 parts by weight of an inorganic additive, with respect to 100 parts by weight of the EVOH resin. When an amount of the inorganic additive is less than 0.1 parts by weight based on 100 parts by weight of the EVOH resin, the addition effect is insignificant, and when an amount of the inorganic additive exceeds 15 parts by weight based on 100 parts by weight of the EVOH resin, dispersibility is lowered, so the inorganic additive is not uniformly distributed and fiber breakage may occur.
The inorganic additive serves to further enhance the cooling effect of the non-woven fabric including the composite fiber.
The inorganic additive may have a thermal conductivity of about 0.5 W/m·K or more. When the thermal conductivity of the inorganic additive is less than about 0.5 W/m·K, a sufficient cooling effect may not be provided.
In addition, the inorganic additive may include titanium dioxide (TiO₂), calcium carbonate (CaCO₃), zinc oxide (ZnO), aluminum oxide (Al₂O₃), graphene, or a combination thereof.
A 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, a high moisture absorption rate and cooling effect may not be obtained, and when the weight ratio of the sheath exceeds 50, fiber spinning is impossible.
Another aspect of the present disclosure provides a highly absorbent non-woven fabric (hereinafter simply referred to as “non-woven fabric”) including the composite fiber.
The non-woven fabric may have a moisture absorption rate (W_f) of about 550% to about 1,500% represented by Equation 1 below:
$\begin{matrix} W_{f} (%) = \frac{Wa (g) - W b (g)}{W b (g)} \times 100, & [Equation 1] \end{matrix}$
wherein in the equation, W_ais a weight of the non-woven fabric sample after moisture absorption, and W_bis a weight of the non-woven fabric sample before moisture absorption.
In addition, the non-woven fabric may have a thermal conductivity of 0.1 W/m·K or more.
Still another aspect of the present disclosure provides an article including the non-woven fabric.
The article may be a sanitary material or a cosmetic mask pack.
Hereinafter, the present disclosure will be described in more detail through examples. These examples are for explaining the present disclosure in more detail, and the scope of the present disclosure is not limited to these examples.

Comparative Example 1: Preparation of Composite Fibers and Non-Woven Fabric

Polypropylene was used as a core, and an EVOH resin with a melting point of 171° C. and a melting index of 50 g/10 min (measurement temperature 210° C., load 2.16 kg) was used as a sheath. A temperature of an extruder for melting the resin was 220° C. As melted resins, the polypropylene moved to the core and the EVOH resin moved to the sheath by a distribution plate in the composite spinning nozzle, and then the melted resins were spun through the nozzle at a speed of 2,500 mpm in a form of a composite cross section to form composite fibers. Thereafter, the composite fibers were opened to form a web, and a non-woven fabric was prepared by calendaring. A core:sheath ratio of the filaments formed above was 70:30 by weight.

Example 1: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that 5 parts by weight of the PEG was added to the sheath, with respect to 100 parts by weight of the EVOH resin.

Example 2: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that 5 parts by weight of the PEG was added to the sheath, with respect to 100 parts by weight of the EVOH resin and a weight ratio of core:sheath was changed to 50:50.

Example 3: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that 5 parts by weight of the PEG was added to the sheath, with respect to 100 parts by weight of the EVOH resin and a weight ratio of core:sheath was changed to 90:10.

Example 4: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that 1 part by weight of the PEG was added to the sheath, with respect to 100 parts by weight of the EVOH resin.

Example 5: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that 10 parts by weight of the PEG was added to the sheath, with respect to 100 parts by weight of the EVOH resin.

Comparative Example 2: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that 7 parts by weight of calcium carbonate (CaCO₃) was added to the sheath, with respect to 100 parts by weight of the EVOH resin, as an inorganic additive having a thermal conductivity of 2.5 W/m·K.

Comparative Example 3: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that 7 parts by weight of calcium carbonate (CaCO₃) was added to the sheath, with respect to 100 parts by weight of the EVOH resin, as an inorganic additive having a thermal conductivity of 2.5 W/m·K, and a weight ratio of core:sheath was changed to 50:50.

Comparative Example 4: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that 15 parts by weight of calcium carbonate (CaCO₃) was added to the sheath, with respect to 100 parts by weight of the EVOH resin, as an inorganic additive having a thermal conductivity of 2.5 W/m·K.

Example 6: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that 5 parts by weight of the PEG and 7 parts by weight of calcium carbonate (CaCO₃) were added to the sheath, with respect to 100 parts by weight of the EVOH resin, the calcium carbonate being an inorganic additive having a thermal conductivity of 2.5 W/m·K.

Example 7: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that 5 parts by weight of the PEG and 7 parts by weight of calcium carbonate (CaCO₃) were added to the sheath, with respect to 100 parts by weight of the EVOH resin, the calcium carbonate being an inorganic additive having a thermal conductivity of 2.5 W/m·K, and a weight ratio of core:sheath was changed to 50:50.

Comparative Example 5: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that 5 parts by weight of the PEG was added to the sheath, with respect to 100 parts by weight of the EVOH resin and a weight ratio of core:sheath was changed to 45:55.

Comparative Example 6: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that 5 parts by weight of the PEG was added to the sheath, with respect to 100 parts by weight of the EVOH resin and a weight ratio of core:sheath was changed to 95:5.

Comparative Example 7: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that 0.5 parts by weight of the PEG was added to the sheath, with respect to 100 parts by weight of the EVOH resin.

Comparative Example 8: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that 12 parts by weight of the PEG was added to the sheath, with respect to 100 parts by weight of the EVOH resin.

Comparative Example 9: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that 7 parts by weight of calcium carbonate (CaCO₃) was added to the sheath, with respect to 100 parts by weight of the EVOH resin, as an inorganic additive having a thermal conductivity of 2.5 W/m·K, and a weight ratio of core:sheath was changed to 45:55.

Comparative Example 10: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that 7 parts by weight of calcium carbonate (CaCO₃) was added to the sheath, with respect to 100 parts by weight of the EVOH resin, as an inorganic additive having a thermal conductivity of 2.5 W/m·K, and a weight ratio of core:sheath was changed to 95:5.

Comparative Example 11: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that 17 parts by weight of calcium carbonate (CaCO₃) was added to the sheath, with respect to 100 parts by weight of the EVOH resin, as an inorganic additive having a thermal conductivity of 2.5 W/m·K.

Comparative Example 12: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that 0.5 parts by weight of the PEG and 0.05 parts by weight of calcium carbonate (CaCO₃) were added to the sheath, with respect to 100 parts by weight of the EVOH resin, the calcium carbonate being an inorganic additive having a thermal conductivity of 2.5 W/m·K.

Comparative Example 13: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that 12 parts by weight of the PEG and 17 parts by weight of calcium carbonate (CaCO₃) were added to the sheath, with respect to 100 parts by weight of the EVOH resin, the calcium carbonate being an inorganic additive having a thermal conductivity of 2.5 W/m·K.

Comparative Example 14: Preparation of Composite Fibers and Non-Woven Fabric

Composite fibers and a non-woven fabric were prepared in the same manner as in Comparative Example 1, except that a weight ratio of core:sheath was changed to 100:0.

Evaluation Example

Moisture absorption rates were evaluated according to Equation 1 above, and thermal conductivities were also evaluated, and the results are shown in Table 1 below.

TABLE 1

		Content of
		inorganic
	PEG content	material in
	in sheath	sheath
	(with respect	(with respect
	to 100 parts	to 100 parts
	by weight of	by weight of	Moisture	Thermal
Core:sheath	the EVOH	the EVOH	absorption	conductivity
weight ratio	resin)	resin)	rate (%)	(W/m · K)

Comparative	70:30	0	0	500	0.1
Example 1
Example 1	70:30	5	0	700	0.1
Example 2	50:50	5	0	900	0.1
Example 3	90:10	5	0	600	0.1
Example 4	70:30	1	0	560	0.1
Example 5	70:30	10	0	850	0.1
Comparative	70:30	0	7	500	0.2
Example 2
Comparative	50:50	0	7	500	0.2
Example 3
Comparative	70:30	0	15	500	0.3
Example 4
Example 6	70:30	5	7	700	0.25
Example 7	50:50	5	7	910	0.3
Comparative	45:55	5	0	Non-	Non-
Example 5				spinnable	spinnable
Comparative	95:5	5	0	300	0.1
Example 6
Comparative	70:30	0.5	0	500	0.1
Example 7
Comparative	70:30	12	0	Non-	Non-
Example 8				spinnable	spinnable
Comparative	45:55	0	7	Non-	Non-
Example 9				spinnable	spinnable
Comparative	95:5	0	7	300	0.05
Example 10
Comparative	70:30	0	17	Non-	Non-
Example 11				spinnable	spinnable
Comparative	70:30	0.5	0.05	500	0.1
Example 12
Comparative	70:30	12	17	Non-	Non-
Example 13				spinnable	spinnable
Comparative	100:0	0	0	15	0.05
Example 14

Referring to Table 1, the non-woven fabrics prepared in Examples 1 to 7 were found to be excellent in both moisture absorption rates (≥550%) and thermal conductivities (≥0.1 W/m·K).
On the other hand, the non-woven fabrics prepared in Comparative Examples 1 to 4, 6 to 7, 10, 12 and 14 were found to have excellent thermal conductivities (≥0.1 W/m·K), but low moisture absorption rates (<550%).
In addition, in Comparative Examples 5, 8 to 9, 11 and 13, it was not possible to measure a thermal conductivity or a moisture absorption rate because non-woven fabrics could not be prepared due to non-spinnability of the melted resins.
The present disclosure has been described with reference to drawings and examples, but the these are only given as examples, and it will be appreciated by those of ordinary skill in the art that a variety of modifications and equivalent other embodiments are possible. Accordingly, the true scope of the present disclosure should be determined by the technical idea of the appended claims.
Unless otherwise expressly indicated herein, all numerical values indicating mechanical/thermal properties, compositional percentages, dimensions and/or tolerances, or other characteristics are to be understood as modified by the word “about” or “approximately” in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice, material, manufacturing, and assembly tolerances, and testing capability.
As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”
The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.

Claims

What is claimed is:

1. A composite fiber comprising:

a core comprising a polyolefin-based resin; and a sheath comprising ethylene vinyl alcohol (EVOH) resin.

2. The composite fiber of claim 1, wherein in the composite fiber, a weight ratio of the core to the sheath is about 50 to 90:about 10 to 50.

3. The composite fiber of claim 1, wherein in the composite fiber, a melting index of the sheath is about 10 g/10 min to about 60 g/10 min.

4. A non-woven fabric comprising a composite fiber according to claim 1.

5. The non-woven fabric of claim 4, having a moisture absorption rate of about 550% to about 1,500% and a thermal conductivity of about 0.1 W/m·K or more.

6. An article comprising a non-woven fabric of claim 4.

7. The article of claim 6, wherein the article is a sanitary material or a cosmetic mask pack.