KR102106147B1 - Thin Super-Absorbent Core Layer - Google Patents

Abstract

In the present invention, in the superabsorbent core layer, a ciscore hollow composite fiber and a concavo-convex heterogeneous cross-section fiber are fused between the pulp layers, and the superabsorbent polymer is dispersedly distributed in the mixed fiber, and the ciscore hollow The composite fiber is an eccentric sheath core hollow composite fiber having an eccentric hollow portion, and has a curved cross-sectional shape, and the sheath component is a low melting point polymer that melts at a constant temperature to fuse the mixed fiber and the superabsorbent polymer. In this case, the uneven structured cross-section fiber is composed of a plurality of protrusions and a recessed part embedded into the center, and protrusions and cis cores of adjacent uneven-shaped release cross-section fibers or adjacent to each other Regarding a superabsorbent core layer characterized by being composed of a space portion formed by being surrounded by hollow composite fibers The.

Description

Super absorbent thin film core layer {Thin Super-Absorbent Core Layer}

The present invention relates to a superabsorbent thin film core layer, and more specifically, to a superabsorbent thin film core layer composed of a mixed fiber composed of a ciscore hollow composite fiber composed of a low melting point sheath and an uneven structured cross-section fiber, and a superabsorbent polymer between the pulp layers. will be.

The present invention relates to an ultra-thin absorbent core that can be used in disposable diapers, sanitary napkins as an example, and is composed of a low compression-processed absorption / diffusion region and a high-pressure-processed shape-retaining region, and is remarkably thin, light, and absorbent. It relates to an ultra-thin absorbent core of a disposable diaper that does not disturb the shape of the form by external force without inhibiting the absorption capacity of.

The disposable diaper absorbs body fluids such as blood, urine, and menstrual blood, so that the user can use them hygienically and conveniently. In general, disposable diapers are products that absorb secretions (eg, urine, blood, menstrual blood, etc.) that are excreted by the wearer's various physiological actions, that is, products that absorb urine, feces, menstrual secretions, and vaginal secretions. Examples include diapers used by infants or incontinents, sanitary napkins for women, and panty liners.

These disposable diapers are usually disposed between a liquid-permeable top sheet that directly contacts the wearer's skin when worn and a liquid-impermeable back sheet that forms an outer surface when worn, between the top and back sheets. It consists of an absorbent core (absorbent core), a leg flap (lap) composed of an elastic body and a fastening means as basic components.

Among the above components, the upper sheet is usually soft and does not irritate the wearer's skin. In particular, the upper sheet should have properties that allow liquid body secretions to pass through the absorbent core quickly. . Suitable top sheets as having these properties have been made and used from a wide range of materials such as porous plastic films, natural fibers, synthetic fibers or mixtures of natural and synthetic fibers.

In particular, the absorbent core is a key means to absorb and retain liquid secretions. Therefore, the absorbent core is usually made of fluff pulp and superabsorbent polymer as a liquid absorbent, and tissues wrapping them, and passes through the liquid-permeable top sheet. It absorbs body fluids at a high rate and retains body fluids to prevent the absorbed body fluids from contacting the skin again. The size, shape (e.g., rectangle, hourglass, etc.) of the absorbent core, structure, and absorbent capacity are configured to be suitable for wearers from infants to adults, and the absorbent core is known to adhere to the back sheet, such as adhesive. It is attached and fixed by means.

In addition, in order to quickly absorb secretions excreted by the wearer (for example, urine, blood, menstrual blood, etc.) and provide comfort in use, it has been developed in an ultra-thin form that increases the absorption capacity of the absorption core and makes the thickness thinner. .

Conventional absorbent cores are superabsorbents made using fluff pulp and starch graftcopolymers, crosslinked carboxymethylcellulose derivatives, and modified hydrophilic acrylates made by grinding wood pulp on a fibrous web. It has been prepared by uniformly or intentionally distributing the resin uniformly and then compressing it after adding moisture to improve the strength of the absorbent core.

Recent diapers tend to be lighter and lighter as they continue to develop more ergonomically. This is because it improves breathability due to lightness and thinness when worn, promotes refreshing, and prevents side effects such as itching and rash when worn for a long time with excellent breathability, and consumers prefer thin and light diapers due to advantages such as easy portability. to be.

The ultra-thin absorbent core is a heating chamber that maintains a certain range of temperature after forming a core shape by inhaling through a core forming drum by uniformly or non-uniformly distributing fluff pulp and low-melting synthetic fibers and introducing a super absorbent polymer. By heating a predetermined time through a heating chamber) and applying a predetermined pressure with a heating roller to melt the low-melting synthetic fibers to prepare an absorbent core in which dispersed fluff pulp is combined with each other.

However, because the ultra-thin absorbent core pressurizes the entire absorbent core with a heating roller, the superabsorbent resin is compressed and unable to swell, so that secretions (for example, urine, blood, menstrual blood, etc.) are rapidly compared to conventional absorbent cores. The inhalation property is rapidly reduced, and the surface-drying property (Wet-Back) of the absorbent core is poor, so it is difficult to use it in an actual diaper.

Since the principle of secretion (eg, urine, blood, menstrual blood) being sucked into the absorbent core is achieved by capillary action, suction is smooth when the absorbent core is low-density, but the entire absorbent core is lightly absorbed. The core has a problem in that the suction power of the body fluid and the surface drying property are significantly reduced.

Republic of Korea Patent Publication No. 2004-0078351 is a heat-adhesive release cross-section composite fiber and an absorbent non-woven fabric produced therefrom undergoes a heat-sealing process when manufacturing a non-woven fabric, and the low melting point portion of the sheath is melted to form a shape similar to the core portion in the form of a release cross-section. There is a feature that the absorbency is improved by capillary action in the space created by the deformed adjacent cross-section, but there may be a problem in breathability and light weight due to the crimping property and bulkiness of the composite fiber itself, and there may also be a problem in shape stability. have.

In addition, U.S. Patent Nos. 5798305 and 6225243 describe the point that the core portion can be used in the form of a non-woven fabric and a release cross-section by thermal bonding using a low-melting point polymer in the sheath portion, but may have problems in shape stability.

The present invention aims to provide a core layer excellent in thinness, light weight, and dispersibility by using a pulp layer, a super absorbent polymer, and a mixed fiber as an absorbent layer for sanitary materials.

In addition, the present invention aims to provide a core layer composed of synthetic fibers having good light weight, crimping properties, elasticity, and bulkiness.

In addition, the present invention is to provide a core layer excellent in absorbency and dispersibility using a capillary phenomenon.

In addition, the present invention aims to provide a core layer having excellent porosity and low weight sound absorption and heat retention.

In order to solve the above problems, the present invention, in the superabsorbent core layer, the ciscore hollow composite fiber and the uneven structured cross-section fiber between the pulp layer is composed of mixed fibers fused to each other, and the superabsorbent polymer in the mixed fiber Is distributed, the ciscore hollow composite fiber is an eccentric type ciscore hollow composite fiber with a hollow portion having an eccentric shape, and has a curved cross-sectional shape, and the sheath component is a low melting point polymer and melted at a constant temperature to mix the mixture. It has a characteristic of fusion of fibers and superabsorbent polymers, and the uneven structured cross-section fiber is composed of a plurality of protrusions and a recessed portion concaved into the center, and adjacent or uneven form of protrusions of adjacent uneven-shaped release cross-section fibers. It consists of a projected portion of a heterogeneous single-sided fiber and a space portion formed by a cis-core hollow composite fiber. It provides a superabsorbent core layer with a gong.

In addition, the present invention, the eccentric ciscore hollow composite fiber is spun through a double annular composite spinneret consisting of inner and outer annular spinnerets with regular intervals, and the complex spinneret has 2 to 4 slits at regular intervals. The outer surface of the outer annular detention is a circumferential surface of a certain distance from the center of the outer diameter, and the center (p) of the outer diameter of the outer annular detention and the center (p ') of the inner diameter of the inner annular detention are spaced at a constant rate. The inner surface of the outer annular detention and the inner and outer surfaces of the inner annular detention are composed of one or more curved portions 400 per one slit, the length of the inner diameter of one slit of the inner annular detention versus the outer annular detention The ratio of the length of the outer diameter of one slit of 1: 1.2 to 1.5, the outer annular spinneret is a resin of the sheath part, and the inner annular spinneret is the core part being spun to have a hollow ratio of 7% or more. And it characterized by providing an absorbent core layer.

In addition, in the present invention, the spaced ratio between the center of the outer diameter of the outer annular detention and the center of the inner diameter of the inner annular detention is expressed by the eccentricity (%) of the following equation (1), and the value of the eccentricity (%) Provided is a ciscore hollow composite fiber having excellent bulky characteristics characterized by having a range of 10 to 20%.

In addition, the present invention is composed of any one of polyethylene (PE) or polypropylene (PP) having a melting point of 80 to 165 ° C and a melt flow index (MI) of 15 to 35 (g / 10min, 230 ° C). The core portion provides a superabsorbent core layer characterized by being either polyethylene terephthalate or polypropylene having an intrinsic viscosity (IV) of 0.50 to 0.60 dL / g.

In addition, the present invention provides a superabsorbent core layer characterized in that the uneven structured cross-section fiber is composed of a hollow portion having an empty center.

In addition, the present invention provides a superabsorbent core layer characterized in that the ciscore hollow composite fiber has a fineness of 8 to 20 denier and a fiber length of 45 to 55 mm.

The present invention by means of solving the above problems is a core layer is formed by mutual fusion by a sheath, which is a low-melting part of the ciscore hollow composite fiber, and the ciscore hollow composite fiber is formed with another synthetic fiber having an uneven structured cross-section. The core layer is formed by bonding to secure shape stability, and a space is secured by the irregular cross-section fiber, thereby improving dispersibility due to capillary action.

In addition, the present invention is characterized in that the hollow shape of the sheath core hollow composite fiber has an eccentric structure, thereby maintaining the bulkiness of the core layer by latent crimpability and elasticity, thereby improving shape retention and breathability.

In addition, the present invention is characterized by excellent shape stability by the curved shape of the sheath core portion of the sheath core hollow composite fiber.

1 is a cross-sectional view of the superabsorbent core layer of the present invention.
FIG. 2 is a conceptual diagram of an example of a cross-section of an eccentric ciscore hollow composite fiber composite spinneret with a constant slit spacing.
3 is a conceptual diagram of another embodiment of a cross-section of an eccentric ciscore hollow composite fiber composite spinneret with a constant slit spacing.
Figure 4 is a conceptual diagram of a spinneret corresponding to the protrusion according to a preferred embodiment of the uneven structured cross-section fiber.
5A, 5B, and 5C are conceptual views of uneven structured cross-section fibers according to a preferred embodiment of the present invention.
6A and 6B are conceptual diagrams of a space portion of a mixed fiber produced by fusion bonding according to the present invention.

Hereinafter, a preferred embodiment of the present invention will be described in detail. First, in describing the present invention, detailed descriptions of related known functions or configurations will be omitted so as not to obscure the subject matter of the present invention.

As used herein, the terms 'about', 'substantially', etc. are used in or at a value close to that value when manufacturing and substance tolerances specific to the stated meaning are presented, and the understanding of the invention To aid, accurate or absolute figures are used to prevent unconscionable abusers from unduly using the disclosed disclosure.

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

The pulp layer 10 is composed of an eccentric type core hollow composite fiber 21 and uneven structured heterogeneous cross-section fiber 23 composed of mixed fibers 20 fused to each other, and the superabsorbent polymer (20) in the mixed fibers 20 30) is a scattered structure.

The sheath component is a low melting point polymer that is melted at a constant temperature and has a characteristic of fusing the mixed fiber 20 and the high absorption polymer 30.

The superabsorbent polymer 30 refers to a polymer that exhibits 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 superabsorbent polymer chains. The polymer is generally used as a highly functional material that is essential for realizing slimming and high performance of hygiene products because its absorbency is significantly higher than that of a general polymer material.

In addition, the polymer is usually a white powder and has a property of absorbing and swelling water and gelling instantly when it enters water. 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 a polymer having a super absorbent polymer (30) in the existing pulp layer (10) has a problem in that it is difficult to form a thin film due to the weight and volume of the pulp.

Therefore, a soft pulp layer 10 is used on the upper and lower surfaces of the absorbent layer, which is a surface that comes into contact with the human body, and therein, a super absorbent polymer is used in the mixed fiber 20 in which the ciscore hollow composite fiber 21 and the uneven structured single-sided fiber 23 are fused together. It is more efficient to use the superabsorbent core layer 1 in which (30) is scattered.

The mixed fiber 20 is composed of an eccentric type core hollow fiber 21 and an uneven structured cross-section fiber 23, and a sheath (a) resin that is an epidermal portion of the eccentric type core hollow fiber 21 is provided. It is characterized by being composed of relatively low melting point polymers compared to the resin of the core portion (b).

The core portion (b) of the eccentric hollow composite fiber is composed of polyester (PET) or polypropylene resin, and the sheath portion (a) is polyethylene (PE) or polypropylene (PP) having a melting point of 80 to 165 ° C. It consists of either.

The sheath portion (a) is a low-melting polymer and has a melting point of about 80 ° C to 165 ° C. Polyolefins suitable as such low-melting polymers include polyethylene, such as high density polyethylene, medium density polyethylene, low density polyethylene and linear low density polyethylene, polypropylene, such as isotactic polypropylene and atactic polypropylene; Polybutylenes such as poly (1-butene) and poly (2-butene); Polypentenes such as poly (2-pentene), and poly (4-methyl-1-pentene); Polyvinyl acetate; Polyvinyl chloride; polystyrene; And copolymers thereof, such as ethylene-propylene copolymers, and combinations thereof.

Preferred polyolefins among these are polypropylene, polyethylene, polybutylene, polypentene, polyvinyl acetate and copolymers and blends thereof, and most preferred polyolefins are polypropylene, polyethylene, copolymers of polypropylene and polyethylene, and combinations thereof.

The core portion (b) may be formed of a polyester or polypropylene resin, and more specifically, the polyester resin may include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polytrimethylene. Any one of terephthalate (Poly Trimethyleneterephthalate, PTT) can be used.

When the intrinsic viscosity of the polyester resin is high, the hollow shape in the core portion increases when the hollow cis-core type heat-adhesive composite fiber is manufactured, so that the hollowing ratio of the hollow portion 100 may also decrease, thereby forming the core portion. It will be desirable for the intrinsic viscosity of the polyester to be 0.50 to 0.64 dL / g.

A polypropylene resin may be used instead of the polyester resin of the core part (b), and the melt flow index (MI) is 15 to 35 (g / 10min, 230 ° C).

The fused sheath resin may serve as an adhesive to be fused with the adjacent uneven structured single-sided fibers 23 or mutually fused between the eccentric ciscore hollow composite fibers 21, and additionally with a super absorbent polymer 30. Can be bound.

The eccentric sheath core hollow composite fiber 21 is an eccentric hollow portion in which the hollow portion h is located off-center, and also has a curved cross-sectional shape. Due to the curved shape of the hollow portion (h), the shape retention property of the fiber by external pressure is excellent, and the flexural strength, which is a property to maintain the shape even when the fiber is deformed several times, is high. Therefore, the mixed fibers 20 of the superabsorbent core layer are excellent in shape retention properties due to compression or shape deformation (bending) due to external pressure, thereby making the eccentric ciscore hollow composite fibers 21 and uneven structured single-sided fibers 23 ), It has excellent absorption capacity due to its large holding force, and it is effective in bulkiness and basis weight by the space portion (f, g).

FIG. 2 is a conceptual diagram of an example of a cross-section of an eccentric ciscore hollow composite fiber composite spinneret with a constant slit spacing.

The eccentric cis-core hollow composite fiber 21 is spun through a double annular composite spinneret composed of inner and outer annular clamps with regular intervals.

The composite spinneret is characterized by a double annular shape composed of internal and external annular clamps having mutually constant spacing (s), and the composite spinneret has two to four identically shaped slits at a constant distance.

In general, unstretched hollow composite fibers discharged through a spinneret are swelled by a pressure difference. When the swelling direction is directed toward the hollow portion h, a desired hollow ratio cannot be obtained or a desired cross-sectional shape cannot be obtained depending on the swelling direction.

Therefore, in order to improve the shape stability of the composite fiber of the hollow portion (h), considering the intrinsic viscosity (IV) and the flow index (MI) of the ejected resin, the slits are formed at regular intervals in the annular spinneret. If it does, it is possible to prevent shape deformation due to discharge swelling.

The number of slits may be 2 or more, but preferably 2 to 5 are valid, and more preferably 3 to 4 are valid. In addition, it is reasonable that the intervals of the plurality of slits are the same and the shapes are identical. If the number of slits is small, it may be a problem in cushioning of discharge expansion, and if the number of slits is too large, there may be difficulties in the production and cost of spinnerets.

In addition, in the case of the eccentric-type sheath core composite spinning, the gap s between the outer and inner annular cages through which the sheath portion (a) and the core portion (b) are discharged is also important for shape stability. This is because the degree of swelling during discharging is different because the composition of the resin is different between the sheath and the core.

In addition, the shape of the slope of the slit may be parallel or coincide with an imaginary line coinciding with the extension line of the center of the composite spinneret.

3 is a conceptual diagram of another embodiment of a cross-section of an eccentric ciscore hollow composite fiber composite spinneret with a constant slit spacing. As the width of the slit increases toward the outer edge of the spinneret, the longest width (r) of the slit appears at the outermost edge. Due to the shape of the annular shape, the ratio of discharge expansion is also large because the circumference becomes larger toward the outer side. Therefore, it is possible to supplement the buffering action of the slit in consideration of the difference in swelling according to the distance from the center of the spinneret of the discharged composite yarn. Therefore, if the spacing (s) between the annular custody and the longest width (r) of the slit satisfies the condition of 2.0 <r / s <3.5, the volume change by discharge expansion is the smallest and the longest width (r) of the slit is 0.1 ~ 0.15mm, the interval (s) of the inner and outer annular detention 30 has a feature of 0.03 ~ 0.05mm.

In addition, the outer surface of the outer annular detention is a circumferential surface of a certain distance from the center (p) of the outer diameter,

The center (p) of the outer diameter of the outer annular detention and the center (p ') of the inner diameter of the inner annular detention are spaced at a constant rate, and the center (p) of the outer diameter of the outer annular detention and the inner diameter of the inner annular detention The spaced ratio of the center of p 'is expressed by the eccentricity (%) of the following equation (1), and the eccentricity (%) has a value in the range of 10-20%.

When the eccentricity is more than 10%, the resin expansion ratio of the cis core portion per individual slit varies due to the asymmetry of the slit from the center in the spinning and stretching process, that is, the difference in the slit volume. In general, the smaller the volume of the slit, the smaller the volume expansion, and thus the curl in which the spinning fibers naturally bend in the direction is formed. However, the volume asymmetry of the slit exceeding 20% is so large that the spinning is poor and the shape of the cis-core cross section may be poor.

It is preferable that the sheath portion and the core portion are formed in a weight ratio of 38:62 to 50:50 to form the eccentric sheath core hollow composite fiber of the present invention.

The present invention has characteristics of each slit shape in addition to the characteristics of the slit spacing. The outer surface of the outer annular detention is a circumferential surface of a certain distance from the center, and the inner surface of the outer annular detention 300 and the inner and outer surfaces of the inner annular detention 200 are provided with one or more curved portions 400 per slit. It is configured, the curved portion 400 is characterized in that consisting of a curved or polygonal.

In addition, the ratio of the length of the inner diameter of one slit of the inner annular clamp to the length of the outer diameter of one slit of the outer annular clamp is characterized by 1: 1.2 to 1.5.

This is because, when the ratio exceeds 1.5, the number and intake degree of the curved portion 400 is large, which makes it difficult to radiate. If the ratio is less than 1.2, the effect of increasing the bending stiffness due to the shape of the curved portion 400 may be insignificant.

In addition, the feature of the curved portion 400 in the slit serves to favor the formation of curls in the radial stretching process.

Conventional sheath core hollow composite fiber composite spinneret without the existing curved part 400 has an interfacial separation shape after the stretching process, so that the sheath part and the core part are not coupled to each other and the separation occurs, so that curl formation is impeded. Can be

However, in the present invention, the inner and outer surfaces of the inner annular detention 200 and the inner and outer surfaces of the inner annular detention 200 become one or more indented curved portions 400 per slit, even if interfacial separation does not occur due to the curved interface. The effect may be incomplete.

The eccentric type ciscore hollow composite of the present inventors is advantageous in forming curls after spinning, and additionally, when the crimping process is performed by heat treatment after spinning and stretching, the fibers are more easily formed to curl, and the larger the bending stiffness of the fibers, the larger the curl Easy to maintain shape.

Bending strength refers to the increase in bending as the load increases when bending is added to the fiber, and ultimately, the stress at break is divided by the cross-sectional area.

In the fiber, the bending strength of the hollow fiber with a space in the middle increases more than twice as much as the normal fiber, and when the hollow cross-section has a curved or polygonal shape rather than a circular shape, the bending stiffness becomes greater.

Figure 4 is a conceptual diagram of a spinneret corresponding to the projection according to a preferred embodiment of the uneven structure of the cross-section fiber. By the combination of the number of spinnerets, it is possible to control the number of protrusions (c) of the irregular cross-section fiber 23 according to the present invention.

5A and 5B are conceptual diagrams of uneven cross-section fibers according to a preferred embodiment of the present invention.

In addition, Figure 5c is a view showing a hollow portion (h ') of the empty space in the center of the fiber, which is a cross-section of the uneven structure as a preferred embodiment of the present invention.

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

If the number is less than three, the opening direction angle of the recessed portion d by the protrusion reaches almost 180 degrees, making it difficult to form the space portion f by fusion with the ciscore hollow composite fiber 21. In addition, if the number of protrusions is 8 or more, the number of protrusions may be too large, and thus, after melt spinning of adjacent protrusions (c), it may be difficult to form a desired uneven structure, and also, the space of the depressions (d) may be narrow, so that the adjacent synthetic fiber oil is fused. The space portion (g) formed by this may be narrow.

6A and 6B are conceptual diagrams of the space portion (f, g) of the mixed fiber 20 produced by fusion bonding according to the present invention. The sheath core hollow composite fiber 21 and the uneven structured cross-section fiber 23 are composed of a mixed fiber 20 fused to each other. The sheath of the ciscore hollow composite fiber 21 can be fused with a nearby synthetic fiber as a low melting polymer.

After being fused with adjacent synthetic fibers, a space portion (f) surrounded by a protrusion (c) and a depression (d) between the ciscore hollow composite fiber (21) and the uneven structured cross-section fiber (23) may be generated, In addition, it can be seen that the space portion g generated between the uneven structured heterogeneous cross-section fibers 23 can be generated.

In addition, when there is a hollow portion (h) of an empty space in the center of the uneven structured release cross-section fiber 23, in addition to the space portion (f, g) between the mixed fibers 20, the release cross-section synthetic fiber 23 itself The same function of the space portions f and g by the hollow space hollow portion h can be performed.

The space portion (f, g) and the hollow portion (h, h ') may be a driving force for the movement of the absorbed liquid due to the occurrence of capillaries, and thus, may act as an important factor for the absorption force. In addition, the movement of the absorbed liquid can be diffused in various directions, thereby improving dispersibility. The absorbed liquid reaches the superabsorbent polymer (30) scattered and distributed in the mixed fiber (20), so that the absorbent power can be increased.

The eccentric sheath core hollow composite fiber 21 is preferred to have 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 becomes high and bulky properties may be deteriorated. On the contrary, if the fineness is more than 20 denier, if the fiber thickness is too large, the weight of the core layer may be a problem.

Therefore, the superabsorbent core layer 1 can affect the bulkiness and flexural strength of the sheath core hollow composite fiber 21 and the shape stability of the unshaped cross-sectional fiber 23 and the air permeability and weight reduction by the space portion. Can be seen.

The pulp layer 10 may be used on the upper and lower surfaces of the superabsorbent core layer 1, and may be used for various products as a hygiene absorbent layer.

Hereinafter, the present invention will be described in more detail by examples. However, these examples are only presented to understand the contents of the present invention, and the scope of the present invention should not be interpreted as being limited to these examples.

Example  1-4

Polyethylene terephthalate (PET) polymer, polyethylene (Polyethylene, PE) polymer composed of sheath-core (Sheath-Core) eccentric type cis core hollow composite fiber (21) and polyethylene terephthalate (Polyethylene) terephthalate (PET) polymer is 4De '38mm uneven structure in the form of a short fiber, and the cross-section fiber is evenly mixed in a ratio of 50:50, and after adding superabsorbent polymer 30, carding is followed by pulp layer 10 The mixture was fused at 137 ° C for 2 minutes to prepare a basis weight of 50 g / m2.

At this time, the core portion of the eccentric sheath core hollow composite fiber 21 was 52% by weight of polyester (PET) having an intrinsic viscosity (IV) of 0.55 dL / g, and the sheath portion had a melt flow index MI (g / 10min, 190). Fig. 20, Polyethylene (PE) having a melting point of 100 ° C was used at 48% by weight.

The polyester (PET) and polyethylene (PE) were spun at a spinning speed of 1000 m / min through an eccentric ciscore hollow composite spinneret, and the spun composite fibers were stretched 3.5 times and imparted crimp, 38 It was cut into mm to prepare ciscore composite fibers having a fineness of 4 denier. Table 1 shows the shape of the fiber cage, the size of the spacing of r, slit, ratio (r / s), eccentricity (%) and fineness / fiber length.

Comparative Example 1

It is the same as the conditions of Example 1, there is a feature that there is no protrusion of the uneven structured cross-section fiber, the rest of the values are shown in Table 1.

Comparative Example 2

The conditions are the same as in Example 1, but the r / s value is 4.5, and the rest of the values are shown in Table 1.

Comparative Example 3

The conditions are the same as in Example 1, but the p / q value is 1.8, and the rest of the values are shown in Table 1.

The physical properties were measured by the following method.

(1) Hollow rate (%): The ratio of the area occupied by the hollow was calculated by the following formula through the fiber cross-sectional image measured by an optical microscope.

  -Hollow area / fiber area (including hollow) * 100 (%)

(2) Cis core cross-sectional shape: It was judged visually through the fiber cross-sectional image measured by an optical microscope.

(3) The thickness (mm) was measured after applying the pressure of 10N / m2 for 10 seconds to the initial thickness of 50 mm of the nonwoven specimen.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3


Sheath
core
synthesis
fiber
(Fiber 1) Sheath PE PE PE PE PE PE PE Core PET PP PET PET PET PET PET
Compound radiation detention
shape Figure 2 (a) Figure 2 (b) Figure 2 (c) Figure 3 (a) Figure 2 (a) Figure 2 (a) Figure 4 Eccentricity (%) 15 15 20 10 15 20 30 r Interval (mm) 0.15 0.1 0.12 0.1 0.1 0.15 0.15 s Interval (mm) 0.05 0.05 0.05 0.03 0.05 0.05 0.05 r / s 3 2 2.4 3.3 2 4.5 3 Sectional shape Sectional shape Good Good Good Good Good Bad Bad Fineness / textile length 15De ’/ 51mm 15De ’/ 51mm 15De ’/ 51mm 15De ’/ 51mm 15De ’/ 51mm 5De ’/ 38mm 15De ’/ 51mm Uneven structure cross section fiber
(Fiber 2) projection part
Repair / Hollow
6
5
4
6 / Hollow
none
6
5 Fineness, 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 Thickness (mm) 44 42 41 47 30 31 29 Absorbency (g / g) 15 14 12 16 7 8 7

* Urine absorption: Value of water absorbed divided by weight of test piece (g / g)

As can be seen from Table 1, the embodiments are excellent in shape stability and flexural strength of the eccentric type ciscore hollow composite fiber 21 in the mixed fiber 20 with a value of 41 mm or more based on 50 basis weight (gsm). In addition, the urine absorbency also shows a value of 12 (g / g) or more compared to the weight of the same test piece, and it can be seen that the absorbency due to the space between the mixed fibers 20 is excellent.

In addition, the embodiment has a thickness of 41 or more in the basis weight (gsm) because the constituent fibers of the mixed fibers 20 all have hollow portions (h, h '), so that the volume ratio per certain weight is large.

On the other hand, in Comparative Example 1, in the case where there are no protrusions and hollow portions in the uneven structured cross-section fiber, it is difficult to form the space portion, so it can be seen that the urine absorbency (g / g) is low, and the protrusions also retain the shape of the mixed fiber 20. Also, it can be seen that the degree of thickening (mm) is low due to the influence of Edo.

In Comparative Example 2, if the r / s value in the condition of spin custody of the ciscore hollow fiber satisfies the condition of 2.0 <r / s <3.5, the volumetric deformation due to discharge expansion is the smallest, and the composite spinning is suitable when it exceeds 3.5 Since it does not form a hollow part, it has a low value in basis weight and thickening value by the curved hollow part.

Comparative Example 3 is a case where the eccentricity is 30%, and the center of the composite spinneret is biased in one direction. Since it does not form a hollow part, it has a low value in basis weight and thickening value by the curved hollow part.

The present invention described above is not limited by the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible within the scope of the present invention without departing from the technical spirit of the present invention. It will be clear to those who have the knowledge of

1: core layer 10: pulp layer
20: mixed fiber 30: super absorbent polymer
21: eccentric sheath core hollow composite fiber 23: uneven structure of the cross-section fiber
100: hollow 200: internal annular detention 300: external annular detention 400: curved portion
p: center of the outer diameter of the external annulus
p ': center of the inner diameter of the inner annulus
a: Sheath part b: Core part
c: protrusion d: recess
e: the center of the irregular cross-section fiber
f, g: space part h, h ': hollow part r: longest width of slit s: interval of inner and outer annular detention

Claims (6)

In the super absorbent core layer,
Between the pulp layer, the ciscore hollow composite fiber and the uneven structured cross-section fiber are composed of mixed fibers fused to each other, and the superabsorbent polymer is scattered and distributed in the mixed fiber.
The ciscore hollow composite fiber is an eccentric type ciscore hollow composite fiber with a hollow portion having an eccentric shape, and has a characteristic cross-sectional shape.
The sheath component of the ciscore hollow composite fiber is a low melting point polymer, which is melted at a constant temperature and fuses the mixed fiber and the superabsorbent polymer.
The uneven structured cross-section fiber is composed of a plurality of protrusions and a recessed portion concaved into the center, and the protruding portion and the ciscore hollow composite fiber of the adjacent uneven type of uneven cross-section fibers are adjacent to each other or by the protrusions of the uneven cross-sectional fiber A superabsorbent core layer characterized by being composed of a space portion formed by being surrounded by.
According to claim 1,
The eccentric cis-core hollow composite fiber is spun through a double annular composite spinneret composed of inner and outer annular clamps with regular spacing,
The composite spinneret has 2 to 4 slits at regular intervals,
The outer surface of the outer annular detention is a circumferential surface of a certain distance from the center of the outer diameter,
The center (p) of the outer diameter of the outer annular detention and the center (p ') of the inner diameter of the inner annular detention are spaced at a constant rate,
The inner surface of the outer annular detention and the inner and outer surfaces of the inner annular detention consist of one or more curved portions 400 per slit,
The ratio of the length of the inner diameter of one slit of the inner annular clamp to the length of the outer diameter of one slit of the outer annular clamp is 1: 1.2 to 1.5,
The outer annular spinneret is a resin of the sheath portion, and the inner annular spinneret is a superabsorbent core layer characterized in that the core portion is spun to have a hollow ratio of 7% or more.
According to claim 2,
The spaced ratio between the center of the outer diameter of the outer annular detention and the center of the inner diameter of the inner annular detention is expressed by the eccentricity (%) of the following equation (1), and the value of the eccentricity (%) is 10-20 Superabsorbent core layer characterized by having a range of%.

According to claim 1,
The sheath component of the ciscore hollow composite fiber is composed of either polyethylene (PE) or polypropylene (PP) having a melting point of 80 to 165 ° C and a melt flow index (MI) of 15 to 35 (g / 10min, 230 ° C). The core component of the sheath core hollow composite fiber has an intrinsic viscosity (IV) of 0.50 to 0.60 dL / g, polyethylene terephthalate or polypropylene.
According to claim 1,
The uneven structured cross-section fiber is a superabsorbent core layer characterized by being composed of a hollow portion having an empty center.
According to claim 1,
The eccentric sheath core hollow composite fiber is a superabsorbent core layer characterized in that the fineness is 8 to 20 denier and the fiber length is 45 to 55 mm.

Images