KR20180016114A - Thin Super-Absorbent Core Layer - Google Patents

Abstract

The present invention relates to a super-absorbent core layer in which a sheath-core synthetic fiber having an annular cross section and a synthetic fiber having an irregular structured modified cross section are mutually fused to form a mixed fiber, and super-absorbent polymer is distributed on the mixed fiber. The sheath component is a polymer with a low melting point which is characterized in being melted at a certain temperature to fuse the mixed fiber and the super-absorbent polymer. The synthetic fiber having the irregular structured modified cross section can be formed in a form with a plurality of protrusions and a curved part embedded in the center. The super-absorbent core layer also has a space formed by protrusions of mutually adjacent synthetic fibers having irregular structured modified cross sections, or protrusions of mutually adjacent synthetic fibers and the sheath-core synthetic fiber.

Description

Thin super-absorbent core layer < RTI ID = 0.0 >

The present invention relates to a superabsorbent thin-film core layer, and more particularly to a superabsorbent thin-film core layer composed of a synthetic fiber composed of a low-melting-point sheath, a polygonal cross-section synthetic fiber, and a high-absorption polymer.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultra-thin absorbent core which can be used for disposable diapers and sanitary napkins, for example, and is composed of a low compression processed absorbent / diffusion region and a high- Absorbent core of a disposable diaper which does not deteriorate the absorbing ability of the diaper.

A disposable diaper absorbs body fluids such as blood, urine, and menstrual blood, so that the user can use the sanitary and convenient. In general, a disposable diaper absorbs urine, feces, menstrual secretions and vaginal secretions by absorbing secretions excreted by various physiological functions of the wearer (for example, urine, blood, Diapers, disposable diapers, sanitary napkins, panty liners, etc., which are used by infants or incontinent persons.

Such a disposable diaper includes a liquid permeable top sheet that is in direct contact with the wearer's skin when worn and a liquid impermeable back sheet that forms an outer surface when worn and is disposed between the top and back sheets An absorbent core, a leg flap composed of an elastic body, and fastening means as basic components.

Among the above-mentioned components, the upper sheet is generally made of a soft texture and does not irritate the wearer's skin. In particular, the upper sheet should have physical properties such that the liquid body secretion can pass quickly through the absorbent core . Suitable topsheet materials having such properties are manufactured from a wide range of materials such as punched plastic films, natural fibers, synthetic fibers, or mixtures of natural and synthetic fibers.

In particular, absorbent cores are a key means of absorbing and retaining liquid secretions. Thus, the absorbent core is typically made up of fluff pulp and superabsorbent polymer as a liquid absorbing material, and a tissue that packs them, and has a liquid permeable top sheet, It performs the function of holding body fluids to absorb body fluids at a high rate and prevent the absorbed body fluids from coming into contact with the skin again. The absorbent core may be configured to suit the wearer from infant to adult and the absorbent core may be configured to have a known attachment, such as an adhesive, on the backsheet, such as size, shape (e.g., rectangle, hourglass, etc.) And is attached and fixed by a means.

It has also evolved into an ultra-thin form that increases the absorbent capacity of the absorbent core and makes it thinner to quickly absorb the secretions (e.g., urine, blood, menses, etc.) excreted by the wearer and provide comfort during use .

Conventional absorbent cores can be made from a superabsorbent material made of fluff pulp made by pulverizing wood pulp on a fibrous web with starch graft copolymers, crosslinked carboxymethyl cellulose derivatives, modified hydrophilic acrylates, The resin is uniformly or intentionally unevenly distributed, and then water is added to the resin so as to improve the integrity of the absorbent core, followed by compression.

Recent diapers tend to be more lightweight and slimmer as they develop more ergonomically. It improves freshness by lightness and thinness when worn, and promotes freshness. Prevents side effects such as itching and rashes when worn for a long time due to excellent breathability, and because it is easy to carry, consumers prefer thin and light diapers to be.

The ultra-thin absorbent core is formed by uniformly or non-uniformly distributing the fluff pulp and the low-melting point synthetic fiber, sucking the same through the core-forming drum, injecting the superabsorbent resin to form a core outer shape, heating chamber for a predetermined time while applying a predetermined pressure to the heating roller to melt the low melting point synthetic fibers to produce an absorbent core in which the dispersed fluff pulp is bonded to each other.

However, since the ultra-thin absorbent core presses the entire absorbent core with the heating roller, the superabsorbent resin can not be compressed and swelled, so that the secretions (e.g., urine, blood, menstrual blood, etc.) It is difficult to use the absorbent core in actual diapers because the absorbent properties are drastically reduced and the surface dryness (Wet-Back) of the absorbent core is poor.

Since the principle that the secretion (for example, urine, blood, menstrual blood, etc.) is sucked into the absorbent core is made by the capillary phenomenon and the like, the suction is smooth when the absorbent core is low density, The core has a problem that the suction force of the body fluids and the surface drying property are greatly deteriorated.

Korean Patent Laid-Open Publication No. 2004-0078351 discloses a thermally adhesive heterogeneous cross-section conjugated fiber and an absorbent nonwoven fabric prepared therefrom, which is subjected to a heat bonding process when the nonwoven fabric is manufactured, and the low melting point portion of the sheath is melted and shaped like a core portion There is a characteristic that the space generated by the deformed and adjacent deformation section improves the water absorbency by the capillary action, but there may be a problem in the air permeability and light weight due to the self-winding property and the bulkiness of the composite fiber itself, have.

In addition, US Pat. Nos. 5,798,305 and 6,225,243 disclose that a low melting point polymer is used in the sheath portion to use a core portion in a nonwoven fabric by heat bonding and a modified cross-sectional shape, but there may be a problem in shape stability.

The present invention aims to provide a core layer excellent in thinning, light weight and dispersibility by using pulp, high absorption polymer and mixed fiber as a sanitary reabsorption layer.

Another object of the present invention is to provide a core layer composed of synthetic fibers having good coiling property, elasticity, and flexibility.

Another object of the present invention is to provide a core layer excellent in water absorbability and dispersibility using capillary phenomenon.

Another object of the present invention is to provide a core layer excellent in polarity and low in weight.

In order to solve the above-mentioned problems, the present invention provides a superabsorbent core layer, comprising: a sheath-core synthetic fiber having an annular cross section and a synthetic fiber having a cross- Wherein the sheath component is melted at a constant temperature with a low melting point polymer to fuse the mixed fiber and the high absorption polymer, and the uneven structure cross section synthetic fiber has a plurality of projections and a curved portion And can be constituted by the protrusions of the mutually adjacent uneven-section synthetic fibers, or the space portion formed by the protruding portions of the uneven-shaped synthetic fibers in the adjacent uneven shape and the synthetic fibers in the form of the sheath core / RTI > core layer.

In the present invention, it is preferable that the low melting point polymer of the sheath is polyethylene, the resin of the core is polyethylene terephthalate or polypropylene, or the low melting point polymer of the sheath is polypropylene and the resin of the core is polyethylene terephthalate Thereby providing a superabsorbent core layer having a characteristic.

The present invention also provides a superabsorbent core layer characterized in that the uneven structure cross-section synthetic fibers can be constituted by a hollow portion having a hollow space at the center.

The present invention also provides a superabsorbent core layer characterized in that the sheath core synthetic fiber has a fineness of 8 to 20 denier and a fiber length of 45 to 55 mm.

Further, the present invention provides a superabsorbent core layer characterized in that the sheath core synthetic fiber has an eccentric structure and has a bulky property with a height of 6 mm or more with respect to 50 basis weight (gsm) due to latent crimping due to shrinkage and elasticity of the core portion do.

The present invention according to the above-mentioned object of the present invention is characterized in that a nonwoven fabric is formed by fusion of a sheath which is a low melting point portion of a sheath core synthetic fiber and the sheath core synthetic fiber is combined with another synthetic fiber having a non- The shape stability of the nonwoven fabric is ensured and the dispersibility is improved due to the capillary phenomenon caused by securing the space between the unevenly-shaped cross-section synthetic fibers.

Further, the present invention is characterized in that the bulky nature of the core layer is maintained by the latent crimping property and the elastic force of the sheath core synthetic fiber, and the shape maintenance and the breathability are improved.

In addition, the present invention is characterized in that the synthetic fibers are ensured to have a uniform polarity and a low weight in terms of volume.

1 is a cross-sectional view of a superabsorbent core layer of the present invention.
FIGS. 2A and 2B are conceptual diagrams of cross-sections of one example of a mixed fiber of a sheath core synthetic fiber according to the present invention.
3 is a conceptual view of a spinneret corresponding to a protrusion according to a preferred embodiment of the present invention.
4A, 4B, and 4C are conceptual diagrams of synthetic fibers having a cross-section of a concavo-convex structure according to a preferred embodiment of the present invention.
5A and 5B are conceptual diagrams of the space portion of the mixed fibers produced by fusion bonding according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted so as to avoid obscuring the subject matter of the present invention.

As used herein, the terms " about, " " substantially, " " etc. ", when used to refer to a manufacturing or material tolerance inherent in the stated sense, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure.

1 is a cross-sectional view of a superabsorbent core layer of the present invention.

The present invention relates to a superabsorbent core layer (1) excellent in absorbency and usable for disposable diapers and women's products,

The present invention relates to a method of manufacturing a composite fiber, comprising the steps of: forming a composite fiber (20) having an annular cross section, a sheath core synthetic fiber (21)

The sheath component is characterized by being melted at a constant temperature with a low melting point polymer and fusing the mixed fiber and the high absorption polymer,

The unevenly-shaped synthetic cross-section synthetic fibers 23 may be formed in the form of a plurality of projections c and a curved portion d embedded in the center. The projections c of the uneven- G or the space portions f and g formed by the protruding portion c of the deformed cross-section synthetic fibers 23 and the synthetic fibers 21 in the form of sheath core.

The superabsorbent polymer refers to a polymer exhibiting a fluid absorption phenomenon due to the introduction of a hydrophilic group in a three-dimensional network structure or a single-chain structure through cross-linking between polymer chains. Since the superabsorbent polymer is much higher in absorbency than the general polymer material, it is generally used as a highly functional material which is essential for achieving slimming and high performance of sanitary articles.

The water-absorbent polymer is usually a white powder. When it enters the water, it absorbs water instantaneously and swells to gel. In particular, the sodium acrylate system and the starch / acrylic acid system have an absorption capacity of 100 g / g

The absorbent layer composed of the super absorbent polymer in the pulp layer has been difficult to be formed into a thin film due to the weight and volume of the pulp.

Therefore, it is more efficient to use the soft absorbent core layer 1 in which the soft pulp layer 10 is used as the top and bottom of the absorbent layer which is in contact with the human body, the two synthetic fibers are mixed therein and the superabsorbent polymer 30 is scattered to be.

The two synthetic fibers are composed of a sheath-core synthetic fiber (21) having an annular section and a synthetic fiber (23) having an irregular-shaped cross-section and the sheath (a) , It is characterized by a relatively low melting point polymer.

Wherein the low melting point polymer of the sheath (a) is polyethylene, the resin of the core is either polyethylene terephthalate or polypropylene,

Or the low melting point polymer of the sheath (a) may be polypropylene, and the resin of the core may be polyethylene terephthalate.

The melting point of polyethylene is 126 to 136 占 폚, the melting point of polypropylene is 160 to 167 占 폚, the melting point of polyethylene terephthalate is 260 to 270 占 폚. When polyethylene is used in the sheath, the heating temperature is maintained at about 140 占 폚, When propylene is used, it can be melted by heating to about 170 ° C.

The melted sheath resin functions as an adhesive, and can be fused to the synthetic fibers 23 having a cross-section of the adjacent concave-convex structure and welded together with the sheath core synthetic fibers 21, and can be bonded to the high-absorption polymer.

FIGS. 2A and 2B are conceptual diagrams of a cross section of an example of the sheath core synthetic fiber 21 in the mixed fiber 20 of the present invention. Not only a straight structure in which the core (b) is located at the central portion of the cross section but also an eccentric structure which is biased to one side is also possible.

Eccentricity may be more effective in the potential winding effect due to the shrinkage ratio due to the difference in intrinsic viscosity of the constituent resin of the sheath (a) and core (b).

Fig. 3 is a conceptual view of a spinneret corresponding to a protrusion (c) according to a preferred embodiment of the present invention. The number of protrusions c of the uneven-structured modified cross-section synthetic fibers 23 according to the present invention can be adjusted by combining the number of the spinnerets.

4A and 4B are conceptual diagrams of the synthetic fiber 23, which is a modified cross-section of a concavo-convex structure according to a preferred embodiment of the present invention. And can be produced by a combination of the spinneret shown in Fig. 3, and in general, the protruding radial structure is superior to the circular structure in its ability to cope with the pressing force in the center direction, so that the shape retention of the synthetic fiber can be improved.

FIG. 4c is a view showing hollow space h in an empty space at the center of a synthetic fiber having an irregular-shaped cross section as a preferred embodiment of the present invention.

The number of protrusions of the cross section of the irregular structure is suitably about 3 to 7, more preferably 5 to 6.

If the number is less than 3, the angle of opening of the curved portion d by the projecting portion reaches almost 180 degrees, and it is difficult to form the space portion f due to fusion with the sheath core synthetic fiber 21. If the number of protrusions is more than 8, the adjacent protrusions (c) can be fusion-solidified after fusion of the adjacent protrusions (c), which may make it difficult to form a desired concavo-convex structure. Also, The formed space g can be narrowed.

5A and 5B are conceptual views of the space portions (f, g) of the mixed fibers 20 produced by fusion bonding according to the present invention. And the mixed fibers 20 in which the sheath core synthetic fibers 21 and the synthetic fibers 23 having the irregular and irregular cross section are mutually fused. The sheath of the sheath-core synthetic fiber can be fused with the nearby synthetic fiber as a low-melting-point polymer.

A space portion f surrounded by the projected portion c and the curved portion d between the sheath core synthetic fiber 21 and the synthetic fiber 23 as the uneven structure cross section can be generated after fusion with the adjacent synthetic island, It can be seen that the generated space portion g between the synthetic fibers 23 having the irregularly structured cross-section can be produced.

In addition, in the case where the hollow portion h of the empty space is present at the center of the synthetic fiber 23 having the irregular structure-shaped cross section, the hollow portion h of the modified- It is possible to perform the same function of the space portions f and g by the hollow space h.

The space portions (f, g) and the hollow portion (h) can be a motive force for movement of the absorbed liquid due to the capillary phenomenon. Also, the movement of the absorbed liquid can be diffused in various directions, and the dispersibility can also be improved. The absorbed liquid can reach the high absorption polymer 30 dispersedly distributed in the mixed fibers, and the absorption power can be increased.

The sheath-core synthetic fiber preferably has a fineness of 8 to 20 denier and a fiber length of 45 to 55 mm. If the fineness is less than 8 denier, the density of the sheath may increase and the bulky properties may be deteriorated. On the other hand, if the fiber thickness is excessively larger than 20 denier, the weight of the core layer may become a problem.

In addition, in the case of the eccentric structure, the sheath core synthetic fibers 21 can be further improved in potential winding resistance and elasticity of the core portion due to shrinkage, so that the bulky nature of the sheath core synthetic fibers 21 having a height of 6 mm or more with respect to 50 sheets (gsm) can be secured.

Therefore, it can be seen that the superabsorbent core layer 1 has no influence on the form stability of the synthetic fiber 23, which is a modified cross section of the bulkiness and uneven shape of the sheath core synthetic fiber 21, and the air permeability and weight reduction due to the space portion have.

The pulp layer (10) can be used by being laminated on the upper and lower surfaces of the superabsorbent core layer (1) and can be used for various products as sanitary reabsorbent layers.

Hereinafter, the present invention will be described in more detail with reference to examples. It is to be understood, however, that these examples are provided so as to understand the scope of the present invention, and are not to be construed as limiting the scope of the present invention.

Example 1

Sheath-core synthetic fibers in the form of short fibers of 15 De 51 mm, made of polyethylene terephthalate (PET) polymer and polyethylene (PE) polymer in eccentric sheath-core form, and polyethylene terephthalate , PET) 4De of cross-section with 6 protrusions with irregularities in the cross-section 38mm Short-fiber uneven structure Uniform cross-section After the synthetic fibers were evenly mixed at a ratio of 50:50, Carding) at 137 DEG C for 2 minutes to prepare a basis weight of 50 g / m < 2 >.

Example 2

The same conditions as in Example 1 were used, except that the resin of the core was polypropylene.

Example 3

And the cross-section of the sheath-core synthetic fiber was in the form of a straight face.

Example 4

This is the same as the condition of Example 1 except that a hollow portion is provided in the concavo-convex structure modified cross-section synthetic fiber.

Comparative Example 1

Is characterized in that it is the same as the condition of the embodiment 1, but has an annular shape with no convex portion of the concavo-convex structure modified cross-section synthetic fibers.

Comparative Example 2

The same conditions as in Example 3 were obtained, in which the fineness of the sheath core synthetic fiber was 5 denier and the fiber length was 38 mm.

Comparative Example 3

The same conditions as in Example 1 were used, except that the projections of the unevenly-shaped cross-section synthetic fibers were two.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Sheath Core Synthetic Fiber
(Fiber 1) Sheath PE PE PE PE PE PE PE Core PET PP PET PET PET PET PET Section shape Eccentric Eccentric Justice Eccentric Eccentric Justice Eccentric Fibers / Textiles 15De '/ 51mm 15De '/ 51mm 15De '/ 51mm 15De '/ 51mm 15De '/ 51mm 5De '/ 38mm 15De '/ 51mm Uneven Convex Structure Cross-section Synthetic Fiber
(Fiber 2)
Number of protrusions

6
6
6
6 pieces / hollow part
none
6
2 Cutting, Cut 4De ', 38mm 4De ', 38mm 4De ', 38mm 4De ', 38mm 4De ', 38mm 4De ', 38mm 4De ', 38mm Fiber 1: Fiber 2
Ratio (% by weight) 50:50 50:50 50:50 50:50 50:50 50:50 50:50 Basis weight (gsm) 50 50 50 50 50 50 50 Bulky (mm) 7.3 7.0 6.9 7.4 4.3 3.2 5.7 Urine absorbency (g / g) 15 14 12 16 7 9 7

* Absorbency: The weight of absorbed water divided by the weight of the test piece (g / g)

As can be seen from the above Table 1, the examples have a bulge quality of 6 mm or more in height on a basis of 50 m 2 (gsm), and the absorbency of urine absorbency is more than 10 (g / g) .

In Comparative Example 1, it was found that voids were not easily formed due to the lack of protrusions in the unevenly-shaped cross-section synthetic fibers, and thus the urine absorbency (g / g) was low, and the protrusions also affected the shape retention of the mixed fibers, mm) is low.

In Comparative Example 2, the sheath and fiber length values of the sheath-core synthetic fibers were 5 denier and 38 mm, which were lower than those of the examples, and the low-melting-point polymer content of the sheath was too low. As a result, (G / g) or less.

In Comparative Example 3, the same reason as in Comparative Example 1, that is, in the case where the number of the projections is two, it is difficult to secure a space, so that the absorbency is low.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. It will be clear to those who have knowledge of.

1: core layer 10: pulp layer
20: mixed fibers 30: high absorption polymer
21: sheath core synthetic fiber 23: concave-convex structure, cross-section synthetic fiber
a: System: Core
c: protrusion d: bend
e: center f, g: space portion
h: hollow portion

Claims (5)

In the superabsorbent core layer,
Wherein the sheath-core synthetic fiber having the annular section and the synthetic fiber having the irregular-shaped cross-section are mutually fused, and the high-absorption polymer is scattered on the mixed fiber,
The sheath component is characterized by being melted at a constant temperature with a low melting point polymer and fusing the mixed fiber and the high absorption polymer,
The uneven-section synthetic fiber can be formed in the form of a plurality of projections and a curved portion embedded in the center. By the projections of the uneven-shaped synthetic fibers having the concave-convex shape or the adjacent projected portions of the uneven- And a space portion formed by being surrounded by synthetic fibers in the form of a sheath core.
The method according to claim 1,
The low melting point polymer of the sheath is polyethylene, the resin of the core is either polyethylene terephthalate or polypropylene,
Or the low-melting-point polymer of the sheath is polypropylene, and the resin of the core is polyethylene terephthalate.
The method according to claim 1,
Characterized in that said unevenly-shaped cross-section synthetic fibers can be constituted by a hollow portion having an empty space at the center.
The method according to claim 1,
Wherein the sheath-core synthetic fiber has a fineness of 8 to 20 denier and a fiber length of 45 to 55 mm.
The method according to claim 1,
Characterized in that the sheath core synthetic fiber has an eccentric structure and has a bulky property with a height of 6 mm or more with respect to a 50 basis weight (gsm) due to the latent crimping property by the shrinkage and the elastic force of the core portion.

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