NON-WOVEN FIBER AGGREGATES AND MASK PACK SHEET USING THE SAME

Abstract

The present disclosure relates to a nonwoven fiber assembly and a mask pack sheet using the same, and specifically, to a nonwoven fiber assembly which has excellent bending characteristics for a use in an industrial material, having a pleasant feel and a soft gloss property for a use in clothes or interior decoration, having excellent physical properties such as transparency, skin adhesiveness, absorbency and retention of a solvent such as water, and a smooth surface feeling for use in a sheet mask nonwoven fiber assembly, and includes a lyocell fiber having a large specific surface area, and a mask pack sheet using the nonwoven fiber assembly.

Claims

1. A nonwoven fiber assembly comprising a lyocell fiber prepared by spinning a lyocell spinning dope containing a cellulose pulp and an N-methylmorpholine-N-oxide aqueous solution, wherein a cross-section of lyocell monofilaments included in the lyocell fiber includes a plurality of protrusions, and the plurality of protrusions come in contact with a virtual first circle and a virtual second circle contained inside the virtual first circle, and are integrally formed around the virtual second circle, and the end thereof has a shape in contact with the first virtual circle.

2. The nonwoven fiber assembly according to claim 1, wherein the lyocell spinning dope contains 6 to 16% by weight of cellulose pulp, and 84 to 94% by weight of an N-methylmorpholine-N-oxide aqueous solution.

3. The nonwoven fiber assembly according to claim 1, wherein the cellulose pulp contains 85 to 97% by weight of alpha-cellulose, and has a degree of polymerization (DPw) of 600 to 1700.

4. The nonwoven fiber assembly according to claim 1, wherein the lyocell fiber has a space occupancy ratio of 150 to 300% as defined by Equation 1 below:
Space occupancy ratio (%)=(Area of first virtual circle/Cross-sectional area of lyocell monofilament)×100.  <Equation 1>

5. The nonwoven fiber assembly according to claim 1, wherein the virtual first circle has a radius of 6.0 to 7.8 .

6. The nonwoven fiber assembly according to claim 1, wherein the virtual second circle has a radius of 1.8 to 2.1 .

7. The nonwoven fiber assembly according to claim 1, wherein a center of the virtual first circle may be identical to a center of the second circle.

8. The nonwoven fiber assembly according to claim 1, wherein the lyocell fiber has fineness of 1.0 to 1.5 denier.

9. The nonwoven fiber assembly according to claim 1, wherein the lyocell fiber has a fiber length of 36 to 40 mm.

10. The nonwoven fiber assembly according to claim 1, wherein the number of crimps of the lyocell fiber is 5 to 20 cpi.

11. The nonwoven fiber assembly according to claim 1, wherein an oil content of the lyocell fiber is 0.1 to 0.4% by weight relative to 100% by weight of the lyocell fiber.

12. The nonwoven fiber assembly according to claim 1, wherein a basis weight of the nonwoven fiber aggregate is 30 to 60 g/m.sup.2.

13. The nonwoven fiber assembly according to claim 1, wherein the nonwoven fiber assembly has a thickness of 0.3 to 0.6 mm.

14. The nonwoven fiber assembly according to claim 1, wherein the nonwoven fiber aggregate has a water absorption rate of 1000 to 1600% relative to the weight of the lyocell fiber.

15. The nonwoven fiber assembly according to claim 1, wherein the nonwoven fiber aggregate has transparency of 80 to 84% after water treatment.

16. The nonwoven fiber assembly according to claim 1, wherein the nonwoven fiber aggregate has transparency of 88 to 94% after essence treatment.

17. The nonwoven fiber assembly according to claim 1, wherein the nonwoven fiber aggregate has skin adhesion of 3.6 to 4.2 gf after water treatment.

18. The nonwoven fiber assembly according to claim 1, wherein the nonwoven fiber aggregate has skin adhesion of 4.5 to 5.3 gf after essence treatment.

19. The nonwoven fiber assembly according to claim 1, wherein the nonwoven fiber aggregate has an oil content of 0.001% by weight or less relative to 100% by weight of the nonwoven fiber aggregate.

20. A mask pack sheet using the nonwoven fiber assembly according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0084] FIG. 1 is a view schematically showing a cross-section of a lyocell monofilament contained in a nonwoven fiber assembly according to the one embodiment.

[0085] FIG. 2a is a photograph of a cross-section of the lyocell fiber produced according to Preparation Example 1, FIG. 2b is a photograph of a cross-section of the lyocell fiber produced according to Preparation Example 2, and FIG. 2c is a photograph of a cross-section of the lyocell fiber prepared according to Preparation Example 3.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0086] Hereinafter, the present disclosure will be described in more detail with reference to the following examples. However, the following examples are for illustrative purposes only, and the present disclosure is not limited thereby. It will be apparent to those of ordinary skill in the art that the scope of the invention is not limited to or by these examples.

PREPARATION EXAMPLE

Preparation Example 1

[0087] Cellulose pulp having a degree of polymerization (DPw) of 820 and an alpha-cellulose content of 93.9% was mixed with an N-methylmorpholine-N-oxide/H.sub.2O mixed solvent containing 0.01 wt % of propyl gallate (in a weight ratio of cellulose pulp:N-methylmorpholine-N-oxide/H.sub.2O=90:10), thus preparing a spinning dope having a concentration of 12 wt % for producing a lyocell material.

[0088] First, a spinning nozzle of a spinneret having a plurality of unit holes, each including three holes, was prepared, and the spinning dope was maintained at a spinning temperature of 110° C. in the spinning nozzle. The spinning dope was then spun while adjusting the discharge amount and spinning speed of the spinning dope so that a single fiber fineness of the lyocell monofilament was 1.2 denier. The spinning dope in filament form discharged from the spinning nozzle was supplied to a coagulation solution in a coagulation bath via an air gap zone, thereby preparing a lyocell multifilament.

[0089] At this time, in the air gap zone, the spinning dope was primarily coagulated using cold air at a temperature of 8° C. and a wind speed of 10 m/s. On the other hand, as the coagulation solution, a solution having a temperature of 25° C. and a concentration of 85 wt % water and 15 wt % N-methylmorpholine-N-oxide was used.

[0090] The lyocell multifilaments drawn in the air layer through a draw roller were water-washed using a water-washing solution sprayed using a water-washing device, thereby removing residual N-methylmorpholine-N-oxide. The lyocell multifilaments were uniformly impregnated with oil and allowed the filaments to have an oil content of 0.2%, and were then dried at 150° C. using a drying roller, thus preparing a lyocell fiber including a multifilament made of monofilaments having a multi-lobal cross-section containing three protrusions.

Preparation Example 2

[0091] The lyocell fiber including a multifilament made of a monofilament having a multi-lobal cross-section containing three protrusions was prepared in the same manner as in Preparation Example 1, with the exception that the single fiber fineness of the lyocell monofilament was set to be 1.4 denier.

Preparation Example 3

[0092] The lyocell fiber including a multifilament made of a monofilament having a multi-lobal cross-section containing three protrusions was prepared in the same manner as in Preparation Example 1, with the exception that the single fiber fineness of the lyocell monofilament was set to be 1.5 denier.

Preparation Example 4

[0093] The lyocell fiber including a multifilament made of a monofilament having a multi-lobal cross-section containing three protrusions was prepared in the same manner as in Preparation Example 1, with the exception that the single fiber fineness of the lyocell monofilament was set to be 2.5 denier.

Preparation Example 5

[0094] The lyocell fiber including multifilaments made of monofilaments having a circular cross-section with a cross-sectional diameter of 11.93 was prepared in the same manner as in Preparation Example 1, with the exception that one circular hole was set as a unit hole, a spinneret in which a plurality of unit holes were formed was used, and the wind speed upon air quenching was set to 15 m/s, so that the single fineness of the lyocell monofilament was set to be 1.5 denier.

Preparation Example 6

[0095] The lyocell fiber including a multifilament made of a monofilament having a circular cross-section with a cross-sectional diameter of 13.78 was prepared in the same manner as in Preparation Example 5, with the exception that the single fiber fineness of the lyocell monofilament was set to be 2.0 denier.

[0096] For the lyocell fibers prepared in Preparation Examples 1 to 6, the cross-sectional shape, the cross-sectional area, the fineness, and the space occupancy ratio of the lyocell monofilaments contained in the lyocell fibers were measured and calculated through the following methods, and the results are set forth in Table 1 below.

[0097] (1) Cross-Sectional Shape of the Monofilament Contained in Lyocell Fiber

[0098] A few bundles of fibers were sampled and then rolled together with black cotton. The resultant fiber was processed to be thin and then inserted into a hole in a plate that was used to transversely cut the fiber. Subsequently, the fiber was cut using a razor blade in a way such that the shape of the section thereof was not changed.

[0099] The cut section of the fiber was magnified (×500) and observed using an optical microscope (BX51, manufactured by Olympus Corporation), and the image of the section was stored using a digital camera. The desired cross-sectional image was designated, and the length and area of the major axis and minor axis, fiber thickness, and cross-sectional circumference length were analyzed using an image of the cross-section of the fiber according to the Olympus soft imaging solution program.

[0100] (2) Fineness

[0101] The fineness of the lyocell fiber was calculated from the cross-sectional area of the monofilament of the real lyocell fiber, which was obtained from the cross-section analysis, and the density (1.49 g/cm.sup.2) of the lyocell fiber was determined using the following Equation 2.

Fineness (De)=[Cross-sectional area of monofilament of lyocell fiber (μm.sup.2)×Density of lyocell fiber (g/cm.sup.3)×9000 (m)]/1,000,000  <Equation 2>

[0102] (3) Space Occupancy Ratio

[0103] The space occupancy ratio of the lyocell fiber was calculated using the following Equation 1.

Space occupancy ratio (%)=(Area of first virtual circle/sectional area of monofilament included in lyocell fiber)×100  <Equation 1>

TABLE-US-00001 TABLE 1 Cross-sectional shape of lyocell monofilament Virtual Virtual Virtual Cross-sectional first second first shape of actual Space circle circle circle lyocell occupancy radius radius area monofilament Fineness ratio (L1, μm) (L2, μm) (μm.sup.2) (μm.sup.2) (De) L1/L2 (%) Remarks Preparation 7.35 1.8 169.72 89.56 1.2 4.1 189.5 multi- Example 1 lobal cross- section Preparation 7.7 2.0 186.27 104.97 1.4 3.9 177.4 multi- Example 2 lobal cross- section Preparation 7.8 2.1 191.13 112.13 1.5 3.7 170.4 multi- Example 3 lobal cross- section Preparation 8.0 3.2 201.06 185.77 2.5 2.5 108.23 multi- Example 4 lobal cross- section Preparation 5.965 111.86 1.5 1 100 Circular Example 5 cross- section Preparation 6.89 149.14 2.0 1 100 Circular Example 6 cross- section

[0104] As shown in Table 1, it was confirmed that the lyocell fibers of Preparation Examples 1 to 4 consisting of monofilaments having a multi-lobal cross-section including three protrusions had a larger space occupancy ratio as compared with the lyocell fibers of Preparation Example 5 and Preparation Example 6 made of a monofilament having a circular cross-section.

[0105] At this time, FIGS. 2a to 2c are photographs of cross-sections of the lyocell fibers of Preparation Examples 1 to 3, respectively.

[0106] From these results, it was confirmed that the lyocell fibers of Preparation Examples 1 to 4 each had a large specific surface area, and that the lyocell fibers of Preparation Examples 1 to 4 can be widely applied to fields requiring a large specific surface area.

EXAMPLE

Example 1

[0107] While passing the lyocell fiber prepared in Preparation Example 1 through a steam box (pressure condition of 0.2 kgf/cm.sup.2), it was subjected to a preheating state in which temperature was imparted to the tow, and pressed using a stuffer box compression roller at a pressure of 2.0 kgf/cm.sup.2, thereby preparing a crimped tow in a stuffer box, which was dried through a lattice dryer and then finally cut to prepare a lyocell staple fiber having a fiber length of 38 mm.

[0108] The prepared lyocell staple fiber was subjected to a carding and spunlace process to finally prepare a nonwoven fiber assembly. The raw material input and process speed were adjusted to match the basis weight of the nonwoven fiber aggregate to the values in Table 2, and the deviation of the basis weight of the nonwoven fiber aggregate was set to be in the range of ±10%.

Examples 2 to 4

[0109] The nonwoven fiber aggregate was prepared in the same manner as in in Example 1, except that the lyocell fibers prepared in Preparation Examples 2 to 4 were respectively used, and the basis weight was changed as in Table 2 below.

[0110] The physical property values of the prepared nonwoven fiber aggregate were measured by the following measurement methods, and are shown in Table 2 below.

Comparative Examples 1 and 2

[0111] The nonwoven fiber aggregate was prepared in the same manner as in in Example 1, except that the lyocell fibers prepared in Preparation Examples 5 and 6 were respectively used, and the basis weight was changed as in Table 2 below.

[0112] The physical property values of the prepared nonwoven fiber aggregate were measured by the following measurement methods, and are shown in Table 2 below.

[0113] <Measurement Method>

[0114] (1) Basis Weight (gsm=g/m.sup.2)

[0115] The nonwoven fiber aggregate was sampled with a width of 5 cm and a length of 20 cm, the weight was measured, and the basis weight was calculated according to Equation 3 below.

Basis weight=Weight measured value of nonwoven fiber aggregate sample×100  <Equation 3>

[0116] (2) Thickness

[0117] Measured using Mitutoyo Thickness Gauge 2046F.

[0118] (3) Transparency

[0119] Sample pretreatment: The nonwoven fiber aggregate was immersed in water or essence for 10 minutes.

[0120] A haze meter (Nippon Denshoku Industry, NDH-5000), which is a light transmittance device, was used to measure the transparency of the nonwoven fiber aggregate, and the transmittance at a wavelength of nanometers was measured.

[0121] (4) Absorbency

[0122] The nonwoven fiber aggregate was immersed in water or essence for 10 minutes, the weight before/after immersion was measured, and the ability of the nonwoven fiber aggregate to absorb water or essence was calculated according to Equation 4 below.

Absorbency (%)={(Weight of nonwoven fiber assembly after immersion−Weight of nonwoven fiber assembly before immersion)/Weight of nonwoven fiber assembly before immersion}×100  <Equation 4>

[0123] (5) Skin Adhesion

[0124] The nonwoven fiber assembly was cut into a size of 25 mm×150 mm, immersed in water or essence for 10 minutes, and then attached to a human arm. Immediately after adhesion, the nonwoven fiber aggregate was detached from the skin using an Instron device (Instron-3365), and the adhesive strength (unit gf) was determined.

TABLE-US-00002 TABLE 2 Basis weight Thickness Transparency Absorbency Skin adhesion Lyocell fiber (gsm) (mm) (%) (%) (gf) Example 1 Preparation 40 0.42 Water: 84 Water: 1200 Water: 3.8 Example 1 essence: 92 essence: 1400 essence: 4.9 Example 2 Preparation 50 0.49 Water: 82 Water: 1300 Water: 3.7 Example 2 essence: 90 essence: 1500 essence: 4.7 Example 3 Preparation 60 0.56 Water: 80 Water: 1400 Water: 4.0 Example 3 essence: 88 essence: 1600 essence: 5.1 Example 4 Preparation 40 0.45 Water: 80 Water: 1000 Water: 3.5 Example 4 essence: 90 essence: 1200 essence: 4.5 Comparative Preparation 40 0.4 Water: 79 Water: 950 Water: 3.3 Example 1 Example 6 essence: 88 essence: 1100 essence: 4.3 Comparative Preparation 60 0.52 Water: 78 Water: 1000 Water: 3.5 Example 2 Example 7 essence: 86 essence: 1150 essence: 4.5

[0125] As shown in Table 2, it was confirmed that the nonwoven fabric assemblies of Examples 1 to 4 in which a multi-lobal cross-section containing a plurality of protrusions, particularly the plurality of protrusions come in contact with a virtual first circle and a virtual second circle contained inside the virtual first circle, and are integrally formed around the virtual second circle, and the end thereof has a shape in contact with the first virtual circle, exhibits excellent performance in terms of transparency, water absorption, and adhesion while being thinner than the nonwoven fiber aggregates of Comparative Examples 1 and 2.

[0126] While the present disclosure has been particularly shown and described with reference to specific embodiments thereof, it will be apparent to those skilled in the art that this specific description is merely of a preferred embodiment and that the scope of the invention is not limited thereby. It is therefore intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

EXPLANATION OF REFERENCE NUMERALS

[0127] 1: central part, 2: protrusion, 3: major axis of protrusion, 4: concave part of protrusion, 5: end of protrusion, 11: virtual first circle, 12: virtual second circle