CN115335563B

CN115335563B - Surface material of sanitary material and manufacturing method thereof

Info

Publication number: CN115335563B
Application number: CN202180024842.9A
Authority: CN
Inventors: 松永笃; 森章太朗; 黛宽; 市川太郎; 佐座规仁
Original assignee: Mitsui Chemicals Inc; Unitika Ltd; Mitsui Chemicals Asahi Life Materials Co Ltd
Current assignee: Unitika Ltd; Mitsui Chemicals Asahi Life Materials Co Ltd
Priority date: 2020-03-31
Filing date: 2021-03-17
Publication date: 2025-09-12
Anticipated expiration: 2041-03-17
Also published as: TW202139948A; JPWO2021200145A1; TWI834962B; CN115335563A; JP7291358B2; WO2021200145A1

Abstract

本发明的目的在于提供一种在不降低与皮肤接触的面的皮肤触感的情况下提高耐磨损性的卫生材料的表面材料的制造方法。该卫生材料的表面材料的制造方法由以下工序构成。准备由棉纤维构成的第一纤维网的工序；准备由长纤维构成的无纺布的工序；准备由棉纤维和热熔性短纤维构成的第二纤维网的工序；将第一纤维网、长纤维无纺布和第二纤维网层叠而得到第一层叠体的工序；对第一层叠体施加高压水流而得到纤维抓绒的工序；通过将纤维抓绒加热使热熔性短纤维的表面软化或熔融而将各纤维相互间熔融粘结的工序。所得到的表面材料成为第一纤维网侧的面与皮肤接触的面。The object of the present invention is to provide a method for manufacturing a surface material of a sanitary material that improves wear resistance without reducing the skin feel of the surface in contact with the skin. The method for manufacturing the surface material of the sanitary material comprises the following steps: a step of preparing a first fiber web composed of cotton fibers; a step of preparing a nonwoven fabric composed of long fibers; a step of preparing a second fiber web composed of cotton fibers and heat-fusible staple fibers; a step of stacking the first fiber web, the long fiber nonwoven fabric, and the second fiber web to obtain a first laminate; a step of applying a high-pressure water flow to the first laminate to obtain a fiber fleece; a step of heating the fiber fleece to soften or melt the surface of the heat-fusible staple fibers and melt-bond the fibers to each other. The resulting surface material becomes the surface of the first fiber web side that contacts the skin.

Description

Surface material for sanitary material and method for producing same

Technical Field

The present invention relates to a surface material used in a sanitary material such as a sanitary napkin or disposable diaper at a position where the sanitary material contacts the skin, and a method for producing the same, and more particularly, to a surface material of a sanitary material having good skin feel and excellent abrasion resistance, and a method for producing the same.

Background

Conventionally, a short fiber nonwoven fabric or a long fiber nonwoven fabric has been used as a surface material of a sanitary material. Although the staple fiber nonwoven fabric is excellent in skin touch, it has a disadvantage of low breaking strength. On the other hand, long fiber nonwoven fabrics have a disadvantage of poor skin feel although they have high breaking strength. Accordingly, patent document 1 discloses a surface material of a sanitary material in which a long fiber nonwoven fabric and a specific short fiber nonwoven fabric are joined. A specific staple fiber nonwoven fabric to be placed on the skin side is formed by fusing heat-fusible composite staple fibers of at least 2 thermoplastic resin components having a high melting point and a low melting point together by a low melting point component (patent document 1, claim 1). In addition, as the long fiber nonwoven fabric, a material obtained by fusing at least 2 kinds of thermoplastic resin components having a high melting point and a low melting point, which are fused with each other by a low melting point component, is also used (patent document 1, claim 3).

However, a short fiber nonwoven fabric comprising short fibers of a thermoplastic resin component has a poor skin touch and may cause skin rash as compared with a short fiber nonwoven fabric comprising natural fibers such as cotton fibers and silk fibers. Accordingly, a surface material has been proposed in which a nonwoven fabric made of cotton fibers is used as a short fiber nonwoven fabric, and long fibers in a long fiber nonwoven fabric are entangled with the cotton fibers to be integrated (patent document 2, claim 1).

Patent document 1 Japanese patent laid-open No. 9-117470

Patent document 2 Japanese patent application laid-open No. 3218416

Disclosure of Invention

The present invention is an improvement of the embodiment described in patent document 2, and an object of the present invention is to improve wear resistance without reducing the skin feel of the surface material that contacts the skin.

The method for solving the above-described problems includes the following means.

A method for producing a surface material for sanitary materials, characterized by applying a high-pressure water stream to a first laminate comprising a first fibrous web comprising cotton fibers, a nonwoven fabric comprising long fibers comprising an acrylic polymer, and a second fibrous web comprising cotton fibers and hot-melt short fibers, which are laminated in this order, to thereby obtain a fiber-fleece by interlacing the cotton fibers, the hot-melt short fibers, and the long fibers, and then heating the fiber-fleece to thereby soften or melt the surface of the hot-melt short fibers, whereby the cotton fibers and the long fibers are bonded to each other by the hot-melt short fibers, wherein the first fibrous web side is in contact with the skin.

<2> A method for producing a surface material for sanitary materials, characterized in that a high-pressure water stream is applied to a second laminate comprising a first fibrous web comprising cotton fibers, a second fibrous web comprising cotton fibers and heat-fusible staple fibers, and a nonwoven fabric comprising long fibers comprising an acrylic polymer, the cotton fibers, the heat-fusible staple fibers, and the long fibers being interwoven to obtain a fiber fleece, and the fiber fleece is heated to soften or melt the surface of the heat-fusible staple fibers, whereby the cotton fibers and the long fibers are bonded to each other by the heat-fusible staple fibers, wherein the first fibrous web side is in contact with the skin.

<3> A surface material of a sanitary material, comprising a first web region comprising cotton fibers, a nonwoven fabric region comprising long fibers comprising an acrylic polymer, and a second web region comprising cotton fibers and hot-melt short fibers, which are laminated and integrated in this order, wherein the cotton fibers in the first web region, the long fibers in the nonwoven fabric region, and the cotton fibers and the hot-melt short fibers in the second web region are interwoven, and the cotton fibers and the long fibers are fused by the hot-melt short fibers, and the thickness is 0.50mm or less, and the first web region is in contact with the skin.

According to the present invention, abrasion resistance can be improved without reducing the skin feel of the surface material on the skin-contacting surface.

Detailed Description

In the present invention, the numerical range indicated by "-" means a range including the numerical values described before and after "-" as the lower limit value and the upper limit value.

In the numerical ranges described in stages in the present invention, the upper limit or the lower limit of a certain numerical range may be replaced with the upper limit or the lower limit of another numerical range described in stages. In addition, in the numerical ranges described in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the value shown in the embodiment.

The present invention solves the above problems by using two kinds of cotton fiber webs and adopting a specific manufacturing method. That is, the present invention relates to a method for producing a surface material of a sanitary material, comprising applying a high-pressure water stream to a first laminate comprising a first fibrous web comprising cotton fibers, a nonwoven fabric comprising long fibers comprising an acrylic polymer, and a second fibrous web comprising cotton fibers and hot-melt short fibers, which are laminated in this order, to cause the cotton fibers, the hot-melt short fibers, and the long fibers to interweave with each other to obtain fiber-fluff, and then heating the fiber-fluff to soften or melt the surface of the hot-melt short fibers, thereby bonding the cotton fibers and the long fibers to each other with the hot-melt short fibers, wherein the first fibrous web side is in contact with the skin. In addition, the present invention relates to a method for producing a surface material of a sanitary material, wherein a first laminate comprising a first web of cotton fibers, a second web of cotton fibers and hot-melt short fibers, and a nonwoven fabric comprising long fibers comprising an acrylic polymer are laminated in this order is used instead of the first laminate, wherein the first web side is in contact with the skin.

The first web used in the present invention is substantially composed of only cotton fibers, but hydrophilic fibers such as silk fibers or rayon fibers may be mixed in a small amount. The first web may be obtained by opening and gathering cotton fibers by a known carding method. The first fiber web has a weight per unit area of about 10 to 20g/m ². As the cotton fiber, any conventionally known cotton fiber can be used, and organic cotton, bleached cotton (bleached cotton) or non-absorbent bleached cotton (non-DEGREASED BLEACHED COTTON) is particularly preferable. Since fat components (cotton wax, cotton seed oil, etc., adhering to the surface of raw cotton) remain on the surface of cotton fibers in non-absorbent bleached cotton, body fluid is less likely to spread in the plane direction of the surface material. Therefore, it is preferable that the skin is not easy to get sticky feeling when it is used. Further, bleached cotton is preferably bleached to white, which gives a sanitary material a clean feel.

The second web used in the present invention is composed of cotton fibers and hot melt staple fibers. The cotton fibers are preferably selected from the various cotton fibers mentioned above. As the hot-melt short fiber, a hot-melt short fiber formed of a thermoplastic resin having a melting point is used. For example, polypropylene fibers, polyester fibers, polyamide fibers, or the like may be used. In the present invention, it is preferable to use a hot-melt staple fiber which is a concentric core-sheath composite staple fiber and in which the melting point of the sheath component is lower than that of the core component. This is because the fibers are fusion-bonded to each other by softening or melting only the sheath component of the core-sheath type composite staple fiber. In order to prevent the composite short fiber from shrinking when only the sheath component is softened or melted, a concentric sheath type is preferable. When the hot-melt short fiber is contracted, the obtained surface material is liable to generate wrinkles or the like. Specifically, a concentric core-sheath type composite short fiber having a core component of polypropylene and a sheath component of polyethylene, or a concentric core-sheath type composite short fiber having a core component of polyethylene terephthalate and a sheath component of polyethylene may be used. The fineness and the fiber length of the hot-melt staple fiber are arbitrary, and in general, the fineness is about 1 to 5 dtex and the fiber length is about 10 to 100 mm.

The mixing ratio of the cotton fibers to the hot-melt short fibers in the second fiber web is preferably cotton fibers to hot-melt short fibers=80:20 to 20:80 (mass ratio), more preferably 70:30 to 30:70 (mass ratio), and most preferably 60:40 to 40:60 (mass ratio). When the mixing ratio of the hot-melt short fibers is small, the number of the melt-bonding points between the fibers tends to be small, and the abrasion resistance of the surface material tends to be low. In addition, when the mixing ratio of the hot-melt short fibers is large, the melt adhesion between the fibers is too strong, and the skin feel of the surface material tends to be lowered. The second web may be obtained by a known carding method, and the weight per unit area is also about 10 to 20g/m ².

The nonwoven fabric used in the present invention is a long fiber nonwoven fabric comprising long fibers containing a propylene polymer. The nonwoven fabric is used for improving the strength, particularly the tensile strength, of the surface material of the sanitary material. The content of the long fibers in the long fiber nonwoven fabric is preferably 50 mass% or more, more preferably 90 mass% or more, and still more preferably 99 mass% or more, based on the number of the long fibers. As the propylene-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, 4-methyl-1-pentene and the like can be used. When the α -olefin is copolymerized, the copolymerization amount is preferably 1 to 10 mol%. The long fiber may contain 1 of these polymers alone or 2 or more. The propylene polymer is a polymer containing 50 mass% or more of a structural unit derived from propylene.

The melt flow rate (MFR, ASTM D1238,230 ℃ C., load of 2160 g) of the propylene-based polymer is not particularly limited as long as it is melt-spinnable. For example, the MFR may be 1g/10 min to 1000g/10 min, preferably 5g/10 min to 500g/10 min, more preferably 10g/10 min to 100g/10 min. When the MFR of the propylene polymer is within the above range, the strength tends to be improved, and is preferable.

From the viewpoint of spinnability, the content of the propylene polymer in the long fiber is preferably 90 mass% or more, more preferably 95 mass% to 100 mass%.

The nonwoven fabric used in the present invention may contain various known additives such as antioxidants, heat stabilizers, weather stabilizers, antistatic agents, slip agents, antifogging agents, lubricants, dyes, pigments, natural oils, synthetic oils, waxes, fatty amides, and the like. The content of these additives in the 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 fineness of the long fibers included in the long fiber nonwoven fabric used in the present invention is not particularly limited as long as the effect of the present invention is exhibited, and is preferably 1 to 10 dtex. From the viewpoint of further promoting the interlacing of the first web and the second web and further improving the abrasion resistance, the latitude of the long fibers when the long fibers are uncrimped fibers is more preferably 3 dtex or more, still more preferably 5 dtex or more, and particularly preferably 5 to 10 dtex. From the viewpoint of further promoting the interlacing of fibers and further improving the abrasion resistance, the latitude of the long fiber when the long fiber is a crimped fiber is more preferably 7 dtex or less, further preferably 5 dtex or less, and particularly preferably 1 to 5 dtex.

In addition, it is preferable to use an eccentric core-sheath type composite long fiber as the long fiber. This is because the eccentric core-sheath type composite long fiber exhibits curling due to a difference in shrinkage rate between the core component and the sheath component, and becomes a curled long fiber, and can impart mechanical strength and flexibility to the surface material. The reason why the strength is improved by the presence of the crimped long fibers is not clear, but it is considered that the reason is that a space is internally ensured by the crimped long fibers, and the cotton fibers enter the space and the interlacing tends to be improved. For example, if a propylene homopolymer component is used as the core component and a propylene/α -olefin copolymer component is used as the sheath component, the core component and the sheath component exhibit spiral crimp at different shrinkage levels in the cooling step after melt spinning. The nonwoven fabric used in the present invention may be composed of only uncrimped filaments or only crimped filaments, may be composed of a mixture of uncrimped filaments and crimped filaments, or may be composed of a layer of uncrimped filaments and a layer of crimped filaments.

The nonwoven fabric used in the present invention is generally produced by a so-called spunbonding method, and is preferably subjected to local thermocompression bonding to improve the form stability. From the viewpoint of further excellent abrasion resistance and strength, the nonwoven fabric preferably has a weight per unit area of 10 to 20g/m ². The long fiber nonwoven fabric may be a single-layer long fiber nonwoven fabric composed of 1 layer containing long fibers, or may be a laminated long fiber nonwoven fabric composed of 2 or more layers containing long fibers. The layers included in the laminated long fiber nonwoven fabric may be the same or different.

The first web, nonwoven fabric, and second web are sequentially laminated to obtain a first laminate. Further, the first web, the second web, and the long fiber nonwoven fabric were sequentially laminated to obtain a second laminate. The first laminate or the second laminate is subjected to high-pressure water flow, and the fibers in the first fiber web, the long fiber nonwoven fabric, and the second fiber web are entangled to obtain fiber piles. The high pressure water stream may be applied from either side of the first laminate or the second laminate, but is preferably applied from both sides to interweave the fibers as closely as possible.

By applying a high pressure water flow, the fiber fleece contains water. Therefore, it is necessary to perform drying to evaporate water, and in the step of performing the drying or after the drying, the heat-fusible short fibers are softened or melted, and the fibers are melt-bonded to each other. For example, when a concentric core-sheath type composite staple fiber having a polypropylene core component and a polyethylene sheath component is used as the hot-melt staple fiber, if the drying temperature is set to about 130 ℃, water in the fiber fleece evaporates, and the polyethylene softens or melts, and the fibers are fusion-bonded to each other, whereby a surface material of the sanitary material can be obtained.

Typical examples of the surface material of the sanitary material obtained by using the first laminate are surface materials in which a first web region made of cotton fibers, a nonwoven fabric region containing long fibers containing an acrylic polymer, and a second web region made of cotton fibers and hot-melt short fibers are laminated and integrated in this order, the cotton fibers in the first web region, the long fibers in the nonwoven fabric region, and the cotton fibers and the hot-melt short fibers in the second web region are interwoven with each other, and the cotton fibers and the long fibers are fused by the hot-melt short fibers, and the thickness thereof is 0.50mm or less, and the first web region is in contact with the sanitary material with the skin. Here, the above regions cannot be clearly distinguished, and fibers in one region have already invaded into other regions. In other words, more layers of cotton fibers from the first web than other regions are the first web region, more layers of long fibers from the nonwoven than other regions are the nonwoven region, and more layers of cotton fibers and hot melt staple fibers from the second web than other regions are the second web region. The number of fibers in each region can be counted by cutting the surface material of the sanitary material in the thickness direction and then observing the cross section thereof with a microscope.

The sanitary material has a surface material thickness of 0.50mm or less. When the thickness exceeds 0.50mm, the interlacing and fusion of cotton fibers in the first web region in contact with the skin become loose, and the abrasion resistance is lowered. The surface material of the sanitary material preferably has a weight per unit area of 25g/m ²～50g/m², more preferably 35g/m ²～50g/m². When the weight per unit area is less than 25g/m ², the amount of fibers is small, and thus the fibers tend to be insufficiently entangled with each other. On the other hand, when the weight per unit area exceeds 50g/m ², the interlacing and fusion of the cotton fibers in the first web region and the heat-fusible short fibers in the second web region become loose, and the abrasion resistance tends to be lowered. The air permeability of the surface material of the sanitary material is preferably 100cm ³/cm²/sec to 500cm ³/cm²/sec. If the air permeability exceeds 500cm ³/cm²/sec, the body fluid temporarily absorbed tends to flow back to the skin side easily. On the other hand, when the air permeability is less than 100cm ³/cm²/sec, it becomes difficult to penetrate body fluid, that is, there is a tendency that the strike through property is lowered.

For the tensile strength of the surface material of the sanitary material, the tensile strength in the mechanical direction is preferably 15N/50mm wide to 100N/50mm wide, more preferably 40N/50mm wide to 90N/50mm wide. The tensile strength in the direction perpendicular to the machine direction (width direction) is preferably 10N/50mm wide to 50N/50mm wide. When the tensile strength is less than the lower limit, there is a tendency that the operability in the production of the sanitary material is lowered. In addition, when the tensile strength exceeds the upper limit, the surface material becomes an excessive quality, which is not reasonable. Here, the mechanical direction refers to a conveying direction when the nonwoven fabric is manufactured. Therefore, the tensile strength in the direction of alignment of the long fibers, that is, in the machine direction is high, and the tensile strength in the width direction is low.

The surface material described above can be used as a surface material for sanitary materials such as sanitary napkins and disposable diapers (particularly disposable diapers for infants). Further, since the layer having a large number of cotton fibers (first web region) derived from the first web is used in contact with the skin, the skin feel is good.

With respect to the surface material obtained by the method of the present invention, the hot-melt short fibers contained in the second web invade and interweave into the layer having good skin feel and containing a large amount of cotton fibers from the first web by the high-pressure water flow. Accordingly, since the cotton fibers from the first fiber web are melt-bonded to each other by interlacing and hot-melt short fibers, there is an effect of obtaining a surface material excellent in abrasion resistance.

Examples

The present invention will be described below based on examples.

The following physical properties and characteristics used in the present specification were measured according to the following measurement methods.

(1) Weight per unit area (g/m ²)

Samples of 10 points were collected from the surface material in the machine direction of 100mm by 100mm in the width direction. Then, the weight of each sample was measured, and the total weight was divided by the total area to calculate the weight per unit area (g/m ²).

(2) Thickness (mm)

The thickness of the center and 5 points at four corners of the sample was measured at a load of 7g/m ² using a thickness gauge (model "R1-250", manufactured by PEACOCK Co., ltd., measuring terminal 25 mm. Phi.). Based on the 10-point sample, the thickness was measured by this method, and the average value was taken as the thickness (mm).

(3) Tensile Strength in machine direction (N/50 mm wide)

Samples of 5 points were collected from the surface material in the machine direction of 200 mm. Times.50 mm in the width direction. Then, the breaking strength of each sample was measured according to JIS L1906 using a tensile tester (Autograph AGS-J, manufactured by Shimadzu corporation) under conditions of a distance between chucks of 100mm and a chuck speed of 300 mm/min. The average value of the breaking strength of the 5-point test piece was taken as the tensile strength in the machine direction (N/50 mm width).

(4) Tensile Strength in the width direction (N/50 mm wide)

Samples of 5 points were collected from the surface material in the machine direction 50 mm. Times. The width direction 200 mm. Then, the breaking strength was measured for each sample by the same method as in (3) above. The average value of the breaking strength of the 5-point test piece was taken as the tensile strength in the machine direction (N/50 mm width).

(5) Air permeability (cm ³/cm²/second)

Samples of 5 points were collected from the surface material in the machine direction 150 mm. Times. The width direction 150 mm. Then, the air permeability was measured by a frazier air permeability measuring instrument in accordance with JIS L1906, and the average value of 5-point samples was taken as the air permeability (cm ³/cm²/sec).

(6) Show-through (second)

Samples of 10 points were collected from the surface material in the machine direction of 100mm by 100mm in the width direction. According to EDANA 150.3-96, the measurement was performed using a strikethrough measuring apparatus manufactured by LENTING. That is, a 1-point sample and 5 pieces of filter paper (grade 989, manufactured by intel corporation) of the same size as the sample were stacked, placed in a measuring apparatus, and distilled water (5 ml) was fed thereto to measure the time required until absorption. The amount of distilled water was 5ml each time, and the required time was measured by setting the amount to 1 st time, and further by performing the 2 nd and 3 rd times without changing the filter paper. The sample and the filter paper were replaced, and the time required for each of the remaining 9 samples was measured by the same method. The average of all required times was taken as strike-through (seconds).

(7) Abrasion resistance (secondary)

Samples 220mm in length by 30mm in width at 50 points were taken from the surface material in random directions. The 6 points in this sample were placed on a vibration type friction firmness tester (manufactured by Darong scientific finisher Co., ltd., RT-300S) according to JIS L0849 so that the first fiber web surface was on the friction terminal side, and the abrasion resistance was measured. Specifically, the surface of the friction terminal was coated with a piece of white cotton cloth for friction, and the base material was coated with sandpaper #200, and the friction terminal was slid at a reciprocation speed of 30 times/min, and the number of reciprocations when fiber peeling was observed was measured for all 6-point samples. Then, the measurement was performed 5 times, and the number of rounds was measured each time, and the average value was used as the abrasion resistance (time).

(8) Softness (mm)

From the surface materials, a specimen of 5 points 150mm in the machine direction x 20mm in the width direction and a specimen of 5 points 150mm in the width direction x 20mm in the machine direction were used. Using this sample, flexibility (mm) was measured in a constant temperature chamber having a temperature of 20±2 ℃ and a humidity of 65±2% in accordance with JIS L1096 (6.19.1A rule). That is, the short side of the sample was placed on a smooth surface horizontal table having a 45 ° slope in alignment with the scale base line. Next, the movement length (mm) of the position of the other end when the center point of one end of the sample and the inclined surface are in contact with each other was measured by a scale by manually sliding the sample in the direction of the inclined surface. For the 1-point sample, the surface and back movement lengths (mm) were measured. The movement length (mm) was measured for 10-point samples, and the average value of 20 movement lengths (mm) was used as the flexibility (mm).

Example 1

[ Preparation of first web ]

Bleached cotton having an average fiber length of 25mm was opened and gathered using a parallel carding machine to obtain a first web having a weight per unit area of 17g/m ².

[ Preparation of second web ]

As the hot melt staple fiber, a concentric core-sheath type composite staple fiber (UNITIKA, manufactured by the company, titre 2.2 dtex, fiber length 51 mm) was used, the sheath component of which was polyethylene having a melting point of 130 ℃ and the core component of which was polyethylene terephthalate having a melting point of 260 ℃. Then, 50 mass% of bleached cotton having an average fiber length of 25mm was uniformly mixed with 50 mass% of the hot-melt short fibers, and the mixture was opened and gathered by a random carding machine to obtain a second web having a weight per unit area of 15g/m ².

[ Preparation of nonwoven fabrics ]

A long fiber nonwoven fabric having a total bonded area of 18% and a weight per unit area of 13g/m ² was obtained by using a propylene homopolymer having a melting point of 162℃and an MFR of 30g/10 min (the MFR was measured at a temperature of 230℃under a load of 2.16kg according to ASTM D1238. Hereinafter, the measurement of the MFR was the same.).

The first web, nonwoven fabric, and second web prepared as described above were sequentially laminated to obtain a first laminate. The first laminate was placed on a stainless steel conveyor belt and conveyed, and a high-pressure water stream was applied from the second web side at a discharge pressure of 3MPa by a high-pressure water stream discharge device (a device in which discharge holes having a hole diameter of 0.1mm are arranged in a row laterally at a hole spacing of 0.6 mm), and then a high-pressure water stream was applied at a discharge pressure of 6 MPa. Then, a high-pressure water flow was applied from the first web side at a jet pressure of 6MPa, resulting in fiber fleece. The fiber fleece is heated at 120 ℃ for 120 seconds to evaporate water in the fiber fleece, and simultaneously only the polyethylene of the concentric core-sheath type composite short fiber is softened or melted to obtain the surface material with the fibers mutually fused and bonded.

Example 2

A surface material was obtained in the same manner as in example 1, except that the mass ratio of bleached cotton to the hot-melt short fibers in the second web was changed to 70 mass% of bleached cotton and 30 mass% of the hot-melt short fibers.

Example 3

A surface material was obtained in the same manner as in example 1, except that the heating temperature of the fiber fleece was changed to 135 ℃ instead of 120 ℃ in example 1.

Example 4

A surface material was obtained in the same manner as in example 1, except that in example 1, a 15-mesh conveyor belt was used instead of the stainless steel conveyor belt for conveying the first laminate.

Example 5

A surface material was obtained in the same manner as in example 1, except that a nonwoven fabric prepared by the method described below was used instead of the nonwoven fabric used in example 1.

[ Preparation of nonwoven fabrics ]

A first long fiber web having a weight per unit area of 4g/m ² was obtained by melt-spinning a propylene homopolymer having a melting point of 162℃and an MFR of 60g/10 min by a spunbonding method to collect a long fiber having a fineness of 1.7 dtex on a collecting surface. Next, a propylene/ethylene random copolymer (ethylene content: 5.0 mol%) having a melting point of 140 ℃ and an MFR of 60g/10 minutes was used as a sheath component, and the propylene homopolymer was used as a core component, and composite melt-spinning was performed by a spunbond method to collect eccentric core-sheath type composite long fibers having a fineness of 1.7 dtex, wherein the core component was sheath component=20:80 (mass ratio), on the first long fiber web. The net composed of the gathered eccentric core-sheath type composite long fibers had a weight per unit area of 5g/m ². Thereafter, the second long fiber web was gathered on a web composed of eccentric core-sheath type composite long fibers by the same method as in the case of obtaining the first long fiber web, to obtain a laminated long fiber nonwoven fabric in which the first long fiber web, the web composed of eccentric core-sheath type composite long fibers and the second long fiber web were laminated in this order, and the weight per unit area was 13g/m ². The crimp is exhibited in the eccentric core-sheath type composite long fiber.

Comparative example 1

In example 1, a surface material was obtained in the same manner as in example 1, except that a nonwoven fabric was not used.

Comparative example 2

[ Preparation of nonwoven fabrics ]

An ethylene/1-butene copolymer [ product name "NEO-ZEX" NZ50301, density 0.950g/cm ³, MFR (measured at 190 ℃ C., load 2.16kg according to ASTM D1238) ] was used as a sheath component, polyethylene terephthalate (product name "J125" manufactured by Mitsui chemical Co., ltd.) was used as a core component, and a concentric core-sheath type composite filament having a core component of a fineness of 2 dtex of 50:50 (mass ratio) was obtained by composite melt spinning at a resin temperature of 270 ℃ and a single-hole ejection amount of 0.5 g/min/hole, cooling and stretching. After the concentric core-sheath type composite long fiber is gathered into a sheet, hot embossing is performed to obtain a nonwoven fabric with a weight per unit area of 16g/m ².

Comparative example 3

A surface material was obtained in the same manner as in example 1, except that the second web prepared by the method described below was used instead of the second web used in example 1.

[ Preparation of second web ]

100 Mass% of bleached cotton having an average fiber length of 25mm was uniformly mixed and subjected to opening and aggregation by a random carding machine to obtain a second web having a weight per unit area of 15g/m ².

The physical properties of the surface materials obtained in examples 1 to 5 and comparative examples 1 to 3 are shown in Table 1, and the properties thereof are shown in Table 2.

TABLE 1

TABLE 2

From tables 1 and 2, it is understood that the surface material obtained in comparative example 1 does not use nonwoven fabric, and thus has extremely low tensile strength in the machine direction and the width direction, and may be broken and unusable during handling or manufacturing of the sanitary material. In addition, the surface material obtained in comparative example 2 was not a propylene polymer, and therefore, it was poor in softness and poor in skin touch. Further, the surface material obtained in comparative example 3 was poor in abrasion resistance because the hot-melt short fibers were not used.

Example 6

[ Preparation of first web ]

The same first web as used in example 1 was obtained.

[ Preparation of second web ]

As the hot melt staple fiber, a concentric core-sheath type composite staple fiber (UBE EXSYMO, manufactured by the company, titre 2.2 dtex, fiber length 51 mm) was used, the sheath component of which was polyethylene having a melting point of 130 ℃ and the core component of which was polypropylene having a melting point of 160 ℃. Then, 50 mass% of non-absorbent bleached cotton having an average fiber length of 25mm was uniformly mixed with 50 mass% of the hot-melt short fibers, and the mixture was opened and gathered by a random carding machine to obtain a second web having a weight per unit area of 15g/m ².

[ Preparation of nonwoven fabrics ]

A first long fiber web having a weight per unit area of 5g/m ² was obtained by melt-spinning a propylene homopolymer having a melting point of 162℃and an MFR of 60g/10 min by a spunbonding method to collect a long fiber having a fineness of 1.7 dtex on a collecting surface. Next, a propylene/ethylene random copolymer (ethylene content: 5.0 mol%) having a melting point of 140 ℃ and an MFR of 60g/10 minutes was used as a sheath component, and the propylene homopolymer was used as a core component, and composite melt-spinning was performed by a spunbond method to collect eccentric core-sheath type composite long fibers having a fineness of 1.7 dtex, wherein the core component was sheath component=20:80 (mass ratio), on the first long fiber web. The net composed of the gathered eccentric core-sheath type composite long fibers had a weight per unit area of 7g/m ². Thereafter, the second long fiber web was gathered on a web composed of eccentric core-sheath type composite long fibers by the same method as in the case of obtaining the first long fiber web, to obtain a laminated long fiber nonwoven fabric having a weight per unit area of 17g/m ², in which the first long fiber web, the web composed of eccentric core-sheath type composite long fibers, and the second long fiber web were laminated in this order. The crimp is exhibited in the eccentric core-sheath type composite long fiber.

The first web, nonwoven fabric, and second web prepared as described above were sequentially laminated to obtain a first laminate. The first laminate was passed through the high-pressure water jet device used in example 3, and fiber nap was obtained under the same conditions as in example 3, and a surface material was obtained under the same conditions as in example 3.

Example 7

The first web prepared in example 1, the second web prepared in example 1, and the long fiber nonwoven fabric prepared in example 1 were sequentially laminated to obtain a second laminate. The second laminate was passed through the high-pressure water jet device used in example 1, and a high-pressure water jet was applied from the first web side at a jet pressure of 3MPa, and then a high-pressure water jet was applied at a jet pressure of 6 MPa. Thereafter, a high-pressure water flow was applied from the long fiber nonwoven fabric side at a jet pressure of 6MPa, to obtain a fiber fleece. The fiber fleece was heated at 135 ℃ for 120 seconds to evaporate the water in the fiber fleece and to soften or melt only the polyethylene of the concentric core sheath composite staple fibers to obtain a surface material in which the fibers were melt-bonded to each other.

Example 8

A surface material was obtained in the same manner as in example 3, except that a nonwoven fabric prepared by the method described below was used instead of the nonwoven fabric used in example 3.

[ Preparation of Long fiber nonwoven Fabric ]

A propylene/ethylene random copolymer (ethylene content: 5.0 mol%) having a melting point of 140℃and an MFR of 60g/10 min was used as a sheath component, a propylene homopolymer having a melting point of 162℃and an MFR of 60g/10 min was used as a core component, and a composite melt-spun yarn was carried out by a spunbonding method to collect an eccentric core-sheath type composite long fiber having a fineness of 1.7 dtex, which was a core component, of the sheath component=20:80 (mass ratio), on a collecting surface, thereby obtaining a long fiber nonwoven fabric having a unit area weight of 20g/m ². The eccentric core-sheath type composite long fiber in the long fiber nonwoven fabric exhibits curl.

The abrasion resistance of the surface materials obtained in examples 6 to 8 was measured, and as a result, 30 times in example 6, 80 times in example 7, and 73 times in example 8 were measured. Therefore, it was found that the surface materials obtained in examples 6 to 8 were excellent in abrasion resistance on the skin-contacting surface.

Claims

1. A method for producing a surface material for sanitary materials, characterized in that a high-pressure water stream is applied to a first laminate comprising a first fibrous web comprising cotton fibers, a nonwoven fabric comprising long fibers comprising an acrylic polymer, and a second fibrous web comprising cotton fibers and hot-melt short fibers, which are laminated in this order, the cotton fibers, the hot-melt short fibers, and the long fibers are interlaced with each other to obtain fiber-fluff, the fiber-fluff is heated by a drying step to evaporate water in the fiber-fluff, and the surface of the hot-melt short fibers is softened or melted, whereby the cotton fibers and the long fibers are bonded to each other by the hot-melt short fibers, and the first fibrous web side is brought into contact with the skin.

2. A method for producing a surface material for sanitary materials, characterized in that a high-pressure water stream is applied to a second laminate comprising a first web of cotton fibers, a second web of cotton fibers and hot-melt staple fibers, and a nonwoven fabric comprising long fibers comprising an acrylic polymer, the cotton fibers, the hot-melt staple fibers, and the long fibers being laminated in this order, fiber-fluff is obtained by interlacing the cotton fibers, the hot-melt staple fibers, and the long fibers with each other, and then the fiber-fluff is heated by a drying step to evaporate water in the fiber-fluff, and the surface of the hot-melt staple fibers is softened or melted, whereby the cotton fibers and the long fibers are bonded with each other by the hot-melt staple fibers, wherein the first web side is in contact with the skin.

3. The method for producing a surface material of a sanitary material according to claim 1 or 2, wherein the cotton fiber is a non-defatted and bleached cotton fiber.

4. The method for producing a surface material for a sanitary material according to any one of claims 1 to 3, wherein the hot-melt short fiber is a concentric core-sheath type composite short fiber, and the melting point of the sheath component is lower than the melting point of the core component.

5. The method for producing a surface material for a sanitary material according to any one of claims 1 to 4, wherein the nonwoven fabric contains an eccentric core-sheath type composite long fiber which exhibits curling.

6. A surface material for sanitary materials, which comprises a first fiber web region composed of cotton fibers, a nonwoven fabric region containing long fibers containing propylene polymers, and a second fiber web region composed of cotton fibers and hot-melt short fibers, which are laminated and integrated in this order,

The cotton fibers in the first web region, the long fibers in the nonwoven fabric region, and the cotton fibers and the hot-melt short fibers in the second web region are interwoven with each other, and the cotton fibers and the long fibers are fused by the hot-melt short fibers,

The thickness is below 0.50mm,

The first web region is in contact with the skin.

7. The surface material of a sanitary material according to claim 6, wherein the weight per unit area is 25g/m ²～50g/m².

8. The surface material of a sanitary material according to claim 6 or 7, wherein the air permeability is 100cm ³/cm²/sec to 500cm ³/cm²/sec.

9. The surface material of a sanitary material according to any one of claims 6 to 8, wherein the tensile strength in the mechanical direction is 15N/50mm wide to 100N/50mm wide.

10. The surface material of a sanitary material according to any one of claims 6 to 9, wherein the tensile strength in a direction orthogonal to the mechanical direction is 10N/50mm wide to 50N/50mm wide.

11. The surface material of a sanitary material according to any one of claims 6 to 10, wherein the hot-melt staple fiber is a concentric core-sheath type composite staple fiber.

12. The surface material of sanitary material according to claim 11, wherein the core of the hot-melt short fiber comprises polyethylene terephthalate or polypropylene and the sheath comprises polyethylene.

13. The surface material of a sanitary material according to any one of claims 6 to 12, wherein the long fiber is an eccentric core-sheath type composite long fiber.