TW202216099A - Surface material for sanitary material and production method therefor - Google Patents

Abstract

To provide a production method for a surface material for sanitary material, the surface material having improved wear resistance without reducing the feel of the surface that comes in contact with skin. This production method for a surface material for sanitary material comprises the following steps. SMS nonwoven fabric and a cotton fiber web formed from cotton fibers are laminated to obtain a laminated body. The SMS nonwoven fabric herein is obtained by laminating first long fiber nonwoven fabric, ultrafine fiber nonwoven fabric, and second long fiber nonwoven fabric in this order. The laminated body is subjected to high pressure water processing to mutually interlace the cotton fibers and mutually interlace the long fibers. The ultrafine fiber nonwoven fabric is broken with high pressure water to drain off a large amount of the ultrafine fibers and to retain a part of the ultrafine fibers in the part at which cotton fibers are mutually interlaced, causing entanglement. A surface material in which bonding between cotton fibers is strengthened is obtained thereby. The surface on the cotton fiber web-side of the obtained surface material forms the surface that comes in contact with skin.

Description

Surface material of sanitary material and method for producing the same

The present invention relates to a method for producing a surface material for a part of a sanitary material such as a sanitary napkin or a disposable diaper that comes into contact with the skin, and more particularly, to a surface material for a sanitary material having good skin feel and excellent abrasion resistance material manufacturing method.

Conventionally, as a surface material of a sanitary material, a short-fiber nonwoven fabric or a long-fiber nonwoven fabric has been used. The short-fiber nonwoven fabric is excellent in terms of feel to the skin, but has a disadvantage that the breaking strength is low. On the other hand, although the long-fiber nonwoven fabric has high breaking strength, it has the disadvantage of poor skin feel. Therefore, Patent Document 1 discloses a surface material of a sanitary material obtained by joining a long-fiber nonwoven fabric and a specific short-fiber nonwoven fabric. In addition, as the specific short-fiber nonwoven fabric arranged on the skin side, one obtained by fusing heat-fusible composite short fibers of at least two thermoplastic resin components having a high melting point and a low melting point with a low melting point component is used (Patent Document 1). 1. Request item 1). In addition, as long-fiber nonwoven fabrics, thermally fusible composite long fibers having at least two thermoplastic resin components having a high melting point and a low melting point are fused to each other with a low melting point component (Patent Document 1, Claim 3).

However, the short-fiber nonwoven fabric including short fibers containing a thermoplastic resin component is inferior to the short-fiber nonwoven fabric including natural fibers such as cotton fibers and silk fibers, and the skin may also have rashes. Therefore, as a short-fiber nonwoven fabric, a nonwoven fabric containing cotton fibers has been proposed, and a surface material in which the long fibers in the long-fiber nonwoven fabric and the cotton fibers are entangled and integrated has been proposed (Patent Document 2, Claim 1).

Patent Document 1: Japanese Patent Laid-Open No. 9-117470 Patent Document 2: Utility Model Registration No. 3218416

[The problem to be solved by the invention]

The present invention is an improved invention of the design described in Patent Document 2, and its subject is to improve abrasion resistance without reducing the feel of the surface material in contact with the skin. [Means of Solving Problems]

The present invention solves the problem by using a melt-blown nonwoven fabric (for example, Japanese Patent Laid-Open No. 2019-209121), which is often used as a leak-proof material for hygienic materials, as a material for a surface material and adopting a specific manufacturing method. subject. That is, the present invention relates to a method for producing a surface material of a sanitary material, characterized in that a cotton fiber web containing cotton fibers, a first long-fiber nonwoven fabric containing long fibers containing a propylene-based polymer, and Ultrafine fiber nonwoven fabric including ultrafine fibers containing a propylene polymer and having a fiber diameter smaller than that of the cotton fibers and the long fibers, and a second long fiber nonwoven fabric including long fibers containing a propylene polymer A high-pressure water flow is applied to the laminated body of the ultrafine fiber nonwoven fabric, and the ultrafine fibers are entangled with the cotton fibers, wherein the cotton fiber web side is in contact with the skin. In addition, it relates to a surface material of a sanitary material, which includes a cotton fiber web region composed of cotton fibers, and a region including long fibers containing a propylene polymer, and the fiber diameter is larger than that of the cotton fibers and the longer fibers. The ultrafine fibers with a small fiber diameter are intertwined with the cotton fibers and the long fibers. [Effect of invention]

In the method of the present invention, a high-pressure water flow is applied to a laminate including an ultrafine fiber nonwoven fabric, the ultrafine fiber nonwoven fabric is destroyed, a large number of ultrafine fibers flow out, and a part of the ultrafine fibers is retained and entangled in the interwoven portion of the cotton fibers. Therefore, in the surface material obtained by the method of this invention, the bond between cotton fibers becomes firm, and the effect of improving the abrasion resistance of the cotton fiber web surface in contact with the skin is exhibited.

The cotton fiber web used in the present invention is mainly composed of cotton fibers. In addition to cotton fibers, hydrophilic fibers such as silk fibers and rayon fibers may be mixed. The cotton fiber web can be obtained by opening and agglomerating cotton fibers by a known carding method. The basis weight of the cotton fiber web is about 10 g/m ² to 20 g/m ² . As the cotton fiber, non-degreased (non-degreased cotton) is preferably used, and non-degreased and bleached (non-degreased bleached cotton) is more preferably used. In non-degreased cotton, since oil and fat components (cotton wax and cottonseed oil adhering to the surface of the raw cotton) remain on the surface of the cotton fiber, body fluids are not easily diffused in the surface direction of the surface material. Therefore, it is not easy to be sticky to the skin during use, which is preferable. Furthermore, non-degreased bleached cotton is bleached to white, and it is preferable to give a clean feeling to the sanitary material. In addition, in this specification, the numerical range represented using "-" means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit.

The long fibers constituting the first long fiber nonwoven fabric and the second long fiber nonwoven fabric used in the present invention contain a polypropylene-based polymer. Since the surface material of this invention contains the area|region derived from the 1st long-fiber nonwoven fabric and the 2nd long-fiber nonwoven fabric, there exists a tendency for the tensile strength to be more excellent. From the viewpoint of further improving the tensile strength of the surface material, the content of the long fibers in the long-fiber nonwoven fabric is preferably 50% or more, more preferably 90% or more, and further preferably 99% or more, based on the number of fibers. . In addition, from the viewpoint of spinnability, the content of the propylene-based polymer in the long fibers is preferably 90% by mass or more, more preferably 99% by mass or more. In addition, in this specification, within the numerical range described in stages, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in another stage. In addition, within the numerical range described in this specification, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the value shown in an Example.

As the polypropylene-based polymer, a propylene homopolymer, a propylene/α-olefin random copolymer, a propylene/α-olefin block copolymer, or the like can be used. Here, as the α-olefin, α-olefins other than propylene, such as ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and 4-methyl-1-pentene, can be used. Furthermore, in the case of copolymerizing an α-olefin, the copolymerization amount thereof is preferably 1 mol % to 10 mol %. The fibers may contain one of these polymers alone, or two or more of them may be contained. In addition, a propylene-type polymer means the polymer which contains 50 mass % or more of structural units derived from propylene.

Regarding the melt flow rate (MFR (melt flow rate), American Society for Testing Materials, ASTM) D1238, 230°C, load of 2160 g) of the propylene-based polymer contained in the long fibers, as long as it can be melted Spinning is not particularly limited. For example, the MFR may be 1 g/10 minutes to 1000 g/10 minutes, preferably 5 g/10 minutes to 500 g/10 minutes, and more preferably 10 g/10 minutes to 100 g/10 minutes. When the MFR of the propylene-based polymer is within the above range, the tensile strength tends to be improved, which is preferable.

The average fiber diameter of the long fibers is not particularly limited as long as the effect of the present invention is exhibited, and from the viewpoint of further improving the abrasion resistance and tensile strength, it is preferably 10 μm to 50 μm, more preferably 11 μm to 30 μm. μm. The average fiber diameter of the long fibers is calculated based on a photograph of a long-fiber nonwoven fabric, as described later in the item of Examples. The photo obtained by the shooting may be a photo obtained by shooting a long-fiber non-woven fabric alone, a photo obtained by shooting a laminate of an ultrafine fiber non-woven fabric and a long-fiber non-woven fabric, or a photo obtained by shooting a surface material. In addition, Fig. 1 is a photograph of the surface of the SMS nonwoven fabric.

The long fibers may be long fibers containing a single component, or may be composite long fibers such as core-sheath type or sea-island type. From the viewpoint of further enhancing the strength of the surface material, it is preferable to contain long fibers of a single component.

The first filament nonwoven fabric and the second filament nonwoven fabric used in the present invention are generally produced by a so-called spunbond method. In addition, the first long-fiber non-woven fabric and the second long-fiber non-woven fabric are preferably subjected to partial thermocompression bonding by thermal embossing to further improve morphological stability.

From the viewpoint of further improving the tensile strength and facilitating the entanglement treatment by the high-pressure water flow described later, the basis weight of each of the first long-fiber nonwoven fabric and the second long-fiber nonwoven fabric is preferably 1 g/m ² to 30 g/ m ² , more preferably 3 g/m ² to 10 g/m ² .

The ultrafine fiber nonwoven fabric sandwiched between the first long fiber nonwoven fabric and the second long fiber nonwoven fabric includes ultrafine fibers containing a propylene-based polymer and having an average fiber diameter of 0.5 μm to 7 μm. The average fiber diameter of the ultrafine fibers is calculated based on a photograph of the ultrafine fiber nonwoven fabric, as described later in the item of Examples. The photograph obtained by the above-mentioned photographing may be a photograph obtained by photographing an ultrafine fiber nonwoven fabric alone, a photograph obtained by photographing a laminate of an ultrafine fiber nonwoven cloth and a long fiber nonwoven cloth, or a photograph obtained by photographing a surface material. Then, a fiber diameter of 8 μm or less was selected for calculation. Therefore, ultrafine fibers are those having a fiber diameter of 8 μm or less.

The monomers constituting the propylene-based polymer contained in the ultrafine fibers and the amounts thereof are the same as those of the propylene-based polymer contained in the long fibers. From the viewpoint of further improving the abrasion resistance, the content rate of the ultrafine fibers in the ultrafine fiber nonwoven fabric is preferably 50% or more, more preferably 90% or more, and still more preferably 99% or more, based on the number of fibers. In addition, from the viewpoint of spinnability, the content of the propylene-based polymer in the ultrafine fibers is preferably 90% by mass or more, more preferably 99% by mass or more.

The MFR of the propylene-based polymer contained in the ultrafine fibers, ASTM D1238, 230° C., load of 2160 g) is not particularly limited as long as melt spinning is possible. For example, the MFR may be 1 g/10 min to 2000 g/10 min, preferably 100 g/10 min to 1500 g/10 min, more preferably 200 g/10 min to 1000 g/10 min. When the MFR of the propylene-based polymer is within the above range, the strength of the ultrafine fibers tends to increase, which is preferable. In addition, when the MFR of the propylene-based polymer is within the above-mentioned range, it is easy to adjust the average fiber diameter to the predetermined range, and there is a tendency that interlacing of fibers interlaced by water flow can be formed more appropriately, which is preferable. Furthermore, the average fiber diameter of the ultrafine fibers is preferably 1 μm to 5 μm from the viewpoint of easier implementation of the entanglement treatment by high-pressure water flow.

The basis weight of the ultrafine fiber nonwoven fabric is preferably from 0.1 g/m ² to 7 g/m from the viewpoints of making it easier to perform the interlacing treatment by high-pressure water flow, further improving the abrasion resistance, and making the workability easier. ² , more preferably 0.3 g/m ² to 5 g/m ² .

The first long fiber nonwoven fabric, the ultrafine fiber nonwoven fabric and the second long fiber nonwoven fabric used in the present invention may contain antioxidants, heat-resistant stabilizers, weather-resistant stabilizers, antistatic agents, slip agents, anti-halation agents, lubricants, dyes, Various known additives such as pigments, natural oils, synthetic oils, waxes, and fatty acid amides. The content of these additives in each nonwoven fabric is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and still more preferably 0.01% by mass or less.

The first long-fiber nonwoven fabric, the ultrafine fiber nonwoven fabric, and the second long-fiber nonwoven fabric may be separately produced and obtained by laminating them, but generally, they are preferably obtained by the following method. That is, an ultrafine fiber web obtained by a so-called melt blowing method is laminated on a first long fiber web obtained by a so-called spunbond method, and a second long fiber web obtained by a so-called spunbond method is further laminated on the ultrafine fiber web. fiber web. After that, the fibers in each web are fused to each other by local thermocompression bonding by hot embossing, thereby obtaining an SMS in which the first long fiber nonwoven fabric, the ultrafine fiber nonwoven fabric and the second long fiber nonwoven fabric are laminated in sequence. The non-woven method is preferred.

The cotton fiber web, the first long fiber nonwoven fabric, the ultrafine fiber nonwoven fabric, and the second long fiber nonwoven fabric are laminated in this order to obtain a laminate. In this case, it is preferable to laminate an SMS nonwoven fabric on a cotton web to obtain a laminate. The reason for this is that it is easier to handle the high-strength SMS non-woven fabric than to handle the ultra-fine fiber non-woven fabric alone. Then, a high-pressure water flow is applied to the layered body. The high-pressure water flow can be applied from the side of the cotton fiber web, from the side of the second long fiber non-woven fabric, or from both sides. By the action of high-pressure water flow, cotton fibers and long fibers are intertwined, but the non-woven fabric of ultra-fine fibers is destroyed, and the ultra-fine fibers are cut or flow out together with the high-pressure water flow. However, some of the ultrafine fibers are retained and entangled in the intertwined portion of cotton fibers or the intertwined portion of long fibers. That is, it is entangled in the intertwined portion of the cotton fibers, so that the bonding between the cotton fibers is stronger. By the above action, the abrasion resistance of the side of the cotton web, that is, the surface in contact with the skin of the surface material is improved. In addition, since the ultrafine fiber nonwoven fabric is destroyed, it no longer has a waterproof function, and becomes a surface material having a body fluid permeability that allows body fluid to pass through appropriately.

On the non-woven side of the second long fiber, other arbitrary fiber webs may be laminated. For example, a mixed fiber web containing cotton fibers and heat-fusible short fibers may be laminated. The weight per unit area of the mixed fiber web is about 10 g/m ² to 20 g/m ² , and the mixing ratio of the cotton fiber and the heat-fusible short fiber in the mixed fiber web is preferably cotton fiber: heat-fusible short fiber=100 : 50 to 150 (mass ratio). As the cotton fiber, the non-degreased cotton or the non-degreased bleached cotton is preferably used. As the heat-fusible short fibers, those formed of a thermoplastic resin having a melting point are used. For example, polypropylene fibers, polyester fibers, or polyamide fibers, etc. are used. In the present invention, it is preferable to use a concentric core-sheath type composite short fiber, and it is a heat-fusible short fiber in which the melting point of the sheath component is lower than the melting point of the core component. By softening or melting only the sheath component of the core-sheath-type composite short fibers, the fibers are fusion-bonded with each other. In order to make the composite short fibers less likely to shrink when only the sheath component is softened or melted, it is preferable to use a concentric core-sheath type. When the heat-fusible short fibers shrink, wrinkles and the like are likely to occur in the obtained surface material. Specifically, the concentric core-sheath type composite staple fiber whose core component is polypropylene and the sheath component is polyethylene, or the concentric core-sheath type composite short fiber whose core component is polyester and whose sheath component is polyethylene is used. The fineness and fiber length of the heat-fusible short fibers are arbitrary, but generally, the fineness is about 1 decitex to 5 decitex, and the fiber length is about 10 mm to 100 mm.

Since water was contained by applying high pressure water flow, it was dried and the water was evaporated. Thereby, the surface material of a sanitary material can be obtained. When the laminated body contains the heat-fusible short fibers, it is preferable to soften or melt the heat-fusible short fibers in the drying step or after the drying, and to fuse and bond the fibers to each other. For example, when using a concentric core-sheath type composite short fiber in which the core component is polypropylene and the sheath component is polyethylene as the heat-fusible short fiber, when the drying temperature is set to about 130° C., the water evaporates and polymerizes at the same time. Ethylene softens or melts, and each fiber is welded and bonded to each other, so that a surface material with excellent morphological stability can be obtained.

The obtained surface material is a surface material of a sanitary material including a cotton fiber web region containing cotton fibers, and a region including long fibers containing a propylene polymer, and the fiber diameter is larger than that of the cotton fibers and the Ultrafine fibers with a small fiber diameter of the long fibers are intertwined with the cotton fibers and the long fibers. Here, the cotton fiber web region and the region containing long fibers cannot be clearly distinguished, and fibers in each region invade other regions. That is, a region containing relatively many cotton fibers becomes a cotton fiber web region, and a region containing relatively many long fibers becomes a region containing long fibers. The number of fibers in each region can be determined by cutting the surface material of the sanitary material in the thickness direction, observing the cross section with a microscope, and counting the number of fibers.

The thickness of the surface material is preferably 0.50 mm or less. When the thickness is 0.50 mm or less, the intertwining of the cotton fibers and the ultrafine fibers in contact with the skin is further improved, and the abrasion resistance tends to be further improved. The surface material of the sanitary material of such a thickness can be manufactured by the manufacturing method of this invention, for example. From the viewpoint of further enhancing the strength, the thickness is preferably 0.25 mm or more. The basis weight of the surface material of the sanitary material is preferably 25 g/m ² to 50 g/m ² . When the basis weight is 25 g/m ² or more, the strength tends to be further improved. On the other hand, when the basis weight is 50 g/m ² or less, the intertwining of the cotton fibers and the ultrafine fibers in the cotton fiber web region increases, and the abrasion resistance tends to improve.

Regarding the tensile strength of the surface material of the sanitary material, the tensile strength in the machine direction is preferably 15 N/50 mm wide to 100 N/50 mm wide, more preferably 25 N/50 mm wide to 90 N/50 mm wide , and more preferably 30 N/50 mm wide to 85 N/50 mm wide. In addition, the tensile strength in the direction orthogonal to the machine direction (width direction) is preferably 10 N/50 mm width to 50 N/50 mm width. When the tensile strength is less than the lower limit value, the workability at the time of manufacturing the sanitary material tends to decrease. In addition, when the tensile strength exceeds the upper limit value, it will become a surface material of excessive quality, which is unreasonable. Here, the "machine direction" refers to the conveying direction when producing the nonwoven fabric. That is, it refers to the direction in which the long fibers in the nonwoven fabric are arranged. Therefore, the tensile strength in the machine direction, which is the arrangement direction of the long fibers, is high, and the tensile strength in the width direction is low.

The surface material obtained in the above manner is used as the surface material of sanitary materials such as sanitary napkins, disposable diapers, and masks. Furthermore, since the cotton fiber web side is used in contact with the skin, the skin feels good. [Example]

Hereinafter, the present invention will be described based on the Examples, but the present invention is not limited by the Examples at all. In addition, the following physical properties and characteristics used in this specification were measured by the following measurement methods.

(1) Weight per unit area (g/m ² ) Select a sample of 100 mm in the machine direction x 100 mm in the width direction from the surface material or non-woven fabric. Then, the mass of each sample was measured, and the weight per unit area (g/m ² ) was calculated by dividing the total mass by the total area. (2) Thickness (mm) Using a thickness gauge (manufactured by PEACOCK, product number "R1-250", measuring terminal 25 mmϕ), the weight per unit area of the sample was measured with a load of 7 ^g /m2. Measure the thickness at 5 points in the center and four corners. About 10 samples of the sample whose basis weight was measured, the thickness was measured by the said method, and the average value was made into thickness (mm).

(3) Tensile strength in the machine direction (N/50 mm width) From the surface material, 5 points of specimens with 200 mm in the mechanical direction and 50 mm in the width direction were selected. Then, according to Japanese Industrial Standards (JIS) L 1913, using a tensile testing machine (manufactured by Shimadzu Corporation, autograph AGS-J), the distance between chucks was 100 mm and the head speed was The breaking strength was measured for each sample at 300 mm/min. The average value of the breaking strengths of the 5-point specimens was taken as the tensile strength in the machine direction (N/50 mm width). (4) Tensile strength in the width direction (N/50 mm width) A sample with 50 mm in the mechanical direction x 200 mm in the width direction was selected from the surface material. Then, the breaking strength of each sample was measured by the same method as the above-mentioned (3). The average value of the breaking strengths of the 5-point specimens was defined as the tensile strength in the width direction (N/50 mm width).

(5) Wear resistance (times) 50 samples with a length of 293 mm and a width of 165 mm were selected from the surface material in random directions. According to Japanese Industrial Standards (JIS) L 0849, the 6-point sample was placed in a Gakuchan type rubbing fastness tester (Daei Scientific Precision Manufacturing Co., Ltd. manufactured by the company, model "RT-300"), and measured for wear resistance. When placing the sample, a urethane pad was placed under the sample in advance, and the sample was fixed to a fixture equipped with a Gakuchan type rubbing fastness tester so as not to generate wrinkles. In addition, the surface of the rubbing terminal was covered with a cloth adhesive tape, and a load of 300 g was applied to the rubbing terminal, so that the cloth adhesive tape was brought into contact with the sample. Then, the friction terminal was slid at a reciprocating speed of 30 times/min, and the number of times of reciprocation when cracks were visually observed in all the 6-point samples was measured. The measurement was performed 5 times, and the average value thereof was taken as the abrasion resistance (times). In addition, even if the number of times of reciprocation exceeded 500 times, the measurement was stopped when all the 6-point samples could not be visually cracked, and the number of times of reciprocation was set to 500 times. Therefore, among the values of abrasion resistance (times), 500 times becomes the maximum value.

(6) Average fiber diameter of long fibers Measurements were made based on electron micrographs of the surface of the long-fiber nonwoven. Specifically, a method of measuring the average fiber diameter of long fibers using an SMS nonwoven fabric will be described. Using an electron microscope (manufactured by Hitachi, Ltd., model: S-3500N), a photograph at a magnification of 300 was taken on the surface of the SMS nonwoven fabric. In the photographed photograph, the photographing was repeated until the total number of fibers with a fiber diameter of 9 μm or more located on the surface side of the ultrafine fibers reached 50 or more (n=50). In the obtained photograph, the fiber diameters (widths) of all fibers with a fiber diameter of 9 μm or more on the surface side of the ultrafine fibers were measured, and the arithmetic mean value was set as the long fibers in the long fiber nonwoven fabric on the surface side. average fiber diameter. About the back side, the measurement was performed similarly. (7) Average fiber diameter of ultrafine fibers Measurements are made based on electron micrographs of the surface of the ultrafine fiber nonwoven. Specifically, a method of measuring the average fiber diameter of ultrafine fibers using an SMS nonwoven fabric will be described. Using an electron microscope (manufactured by Hitachi, Ltd., model: S-3500N), a photograph at a magnification of 2000 was taken on the surface of the SMS nonwoven fabric. In the photographed photograph, the photographing was repeated until the total number of fibers having a fiber diameter of 8 μm or less reached 50 (n=50) or more. In the obtained photographs, the fiber diameters (widths) of all fibers having a fiber diameter of 8 μm or less were measured, and the arithmetic mean thereof was defined as the average fiber diameter of the ultrafine fibers in the ultrafine fiber nonwoven fabric. In addition, in the above (6) and (7), the measurement of the diameter (width) of the fiber may be performed at the position where the fiber width is the smallest in the photograph. In addition, when fibers are fused to each other, the measurement may be performed at the unfused portion, and when there is no unfused portion, it may be excluded from the number of fibers.

Example 1 [Preparation of cotton web] Non-degreased bleached cotton having an average fiber length of 25 mm was opened and aggregated using a parallel card to obtain a cotton web having a basis weight of 20 g/m ² .

[Preparation of SMS Nonwoven Fabric] Using propylene with a melting point of 162°C and an MFR of 60 g/10 minutes (MFR is measured at a temperature of 230°C and a load of 2.16 kg in accordance with ASTM D1238. Hereinafter, the measurement method of MFR is the same.) polymer, and melt spinning by the conventional spunbonding method using a spinning nozzle including a plurality of spinning holes of 0.6 mmϕ at a melting temperature of 230°C, and collect long fibers on the collecting surface to obtain the first long fiber web. The average fiber diameter of the long fibers in the first long fiber web was 12.8 μm, and the basis weight of the first long fiber web was 5.75 g/m ² . Next, using a propylene homopolymer having a melting point of 160°C and an MFR of 400 g/10min, the melt melted at a melting temperature of 280°C was ejected from a mold including a plurality of ejection holes of 0.4 mmϕ, and the melt was ejected through the ejection holes. The melt blowing method, a conventional method in which heated air at 280° C. is blown out of the outlet, collects ultrafine fibers on the first long fiber web, thereby obtaining an ultrafine fiber web. The average fiber diameter of the ultrafine fibers in the ultrafine fiber web was 1.4 μm, and the basis weight of the ultrafine fiber web was 1.5 g/m ² . In the same manner as in the method for obtaining the first long fiber web, the long fibers are collected on the ultrafine fiber web to obtain the second long fiber web. The average fiber diameter of the long fibers in the second long fiber web was 12.8 μm, and the basis weight of the second long fiber web was 5.75 g/m ² . The first long fiber web, the ultra-fine fiber web, and the second fiber web were sequentially laminated at the temperature of the embossing roller at 145°C and the temperature of the mirror roller at 150°C so that the total crimping area was 18%. The web formed by the long-fiber web is partially thermocompressed to integrate the three layers, thereby obtaining an SMS non-woven fabric formed by laminating the first long-fiber non-woven fabric, the ultra-fine fiber non-woven fabric and the second long-fiber non-woven fabric in sequence. In addition, the basis weight of the SMS nonwoven fabric was 13 g/m ² .

The layered product prepared above by laminating the cotton fiber web and the SMS non-woven fabric was passed through a high-pressure water jet device (a device in which the jet holes with a diameter of 0.1 mm are arranged in a horizontal line at a hole interval of 0.6 mm), and the cotton fiber web side A high-pressure water flow was applied at a discharge pressure of 3 MPa, followed by a high-pressure water flow at a discharge pressure of 6 MPa. Then, after applying a high-pressure water flow from the side of the second long-fiber nonwoven fabric at a jet pressure of 6 MPa, it was dried at 120° C. to obtain a surface material.

Example 2 [Preparation of cotton fiber web and SMS non-woven fabric] The same cotton web and SMS nonwoven as used in Example 1 were obtained.

[Preparation of hybrid fiber web] As the heat-fusible short fibers, concentric core-sheath type composite short fibers (especially polyethylene terephthalate with a melting point of 130°C as a sheath component and polyethylene terephthalate as a core component with a melting point of 260°C) were used (especially Manufactured by UNITIKA Co., Ltd., fineness 2.2 dtex, fiber length 51 mm). Then, 50 mass % of non-degreased bleached cotton with an average fiber length of 25 mm and 50 mass % of the heat-fusible short fibers were uniformly mixed, and were opened and aggregated by a random card, thereby obtaining a weight per unit area of 17 g. /m ² of mixed fiber webs.

The layered product prepared above, in which the cotton fiber web, the SMS nonwoven fabric, and the mixed fiber web were laminated in this order, was passed through the high-pressure water jet device used in Example 1, and a high-pressure water jet was applied from the cotton web side at a jet pressure of 3 MPa. , and then a high-pressure water flow was applied at a discharge pressure of 6 MPa. Then, after applying a high-pressure water flow from the mixed fiber web side with a jet pressure of 6 MPa, drying was performed to obtain a surface material. Furthermore, when the drying temperature was set to 135° C., only the polyethylene of the concentric core-sheath type composite short fibers was softened or melted, and a surface material in which the fibers were welded and bonded to each other was obtained.

Example 3 In the SMS nonwoven fabric used in Example 1, the basis weight of the first long fiber web and the second long fiber web was changed to 6.25 g/m ² , and the basis weight of the ultrafine fiber web was changed A surface material was obtained in the same manner as in Example 1 except that it was 0.5 g/m ² . In addition, the change of the basis weight was performed by adjusting the moving speed of a collection surface and the discharge amount of an ultrafine fiber.

Comparative Example 1 Instead of using the SMS nonwoven fabric, only a cotton fiber web with a weight per unit area of 35 g/m ² was used, and a high-pressure water flow was applied under the same conditions as in Example 1 to obtain a fabric with a weight per unit area of 35 g/m ² . surface material.

Comparative Example 2 A surface material having a basis weight of 33 g/m ² was obtained in the same manner as in Example 1, except that the long-fiber web obtained by the following method was used instead of the SMS nonwoven fabric. [Manufacture of long-fiber web] Using a propylene homopolymer having a melting point of 162°C and an MFR of 60 g/10min, and a melting temperature of 230°C, using a spinning nozzle including a plurality of spinning holes of 0.6 mmϕ Melt spinning is performed by a conventional method of spunbonding, and long fibers are collected on a collecting surface to obtain a long fiber web. The average fiber diameter of the long fibers in the long fiber web was 33.5 μm, and the basis weight of the long fiber web was 13.0 g/m ² .

The surface materials obtained in Examples 1 to 3, Comparative Example 1, and Comparative Example 2 were evaluated for their basis weight, thickness, tensile strength in the machine direction, and tensile strength in the width direction by the methods described above. and wear resistance. The results are shown in Table 1. From the results in Table 1, it was found that the surface materials obtained in the examples were excellent in abrasion resistance of the surface in contact with the skin.

[Table 1] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Weight per unit area (g/m ² ) 33 47 33 35 33 Thickness (mm) 0.33 0.43 0.34 0.32 0.34 Tensile strength (N/50 mm width) mechanical direction 38 73 36 30 37 width direction 17 26 15 12 16 Wear resistance (times) 500 500 500 200 150

none

Fig. 1 is an electron microscope at a magnification of 300 times of the laminate of the first long fiber nonwoven fabric/ultrafine fiber nonwoven fabric/second long fiber nonwoven fabric (hereinafter, the laminate is also referred to as "spunbond/meltblown/spunbond"). (Spunbond+Meltblown+Spunbond, SMS) non-woven") photos taken on the surface.

Claims (4)

A method for producing a surface material for a sanitary material, comprising: layering a cotton fiber web containing cotton fibers, a first long-fiber nonwoven fabric containing long fibers containing a propylene-based polymer, a nonwoven fabric containing a propylene-based polymer, and A high-pressure water flow is applied to a laminate of an ultrafine fiber nonwoven fabric of ultrafine fibers whose fiber diameters are smaller than those of the cotton fibers and the long fibers, and a second long fiber nonwoven fabric including long fibers of a propylene-based polymer, On the other hand, the ultrafine fiber nonwoven fabric is destroyed, and the ultrafine fibers are entangled with the cotton fibers, wherein the cotton fiber web side is in contact with the skin. The method for producing a surface material of a sanitary material according to claim 1, wherein the cotton fiber is non-degreased and bleached. The method for producing a surface material of a sanitary material according to claim 1 or claim 2, wherein the ultrafine fiber nonwoven fabric has a basis weight of 0.1 g/m ² to 7 g/m ² . A surface material of a sanitary material, comprising: a cotton fiber web region composed of cotton fibers, and a region including long fibers containing a propylene polymer, and the fiber diameter is smaller than that of the cotton fibers and the long fibers. Ultrafine fibers are interwoven with the cotton fibers and the long fibers.

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