JPH11131350A - Nonwoven fabric from extremely fine fiber having open pore - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide nonwoven fabric having increased liquid permeability and air permeability. SOLUTION: This nonwoven fabric is constituted with conjugated continuous filaments. The continuous filament are produced by conjugating a low-melting thermoplastic polymer component A and a high-melting thermoplastic polymer component B. The component A and the component B are exposed to the surface of the fiber. In the nonwoven fabric, the fusing areas and the fiber-split areas are arranged to that they may become mutually adjacent. In the fiber-split area, the fibers A made of only split polymer A, the fibers B made of only split polymer B and not-split conjugated continuous filaments distribute as they form the regions in which they are entangled substantially in the three dimension and the regions in which open pores are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microfiber nonwoven fabric, and more particularly to a microfiber nonwoven fabric having openings suitable for use as a surface material of sanitary materials.

[0002]

2. Description of the Related Art Various nonwoven fabrics having a large number of apertures have been known. For example, a web obtained by a melt blown method is subjected to a high-pressure liquid flow treatment, and the fibers are entangled with each other, and a nonwoven fabric (Japanese Patent No. 2543597) or a web obtained by a card method or a papermaking method is subjected to a high-pressure liquid flow treatment. There is a nonwoven fabric in which fibers are entangled with each other. However, in the case of the melt blown method, polymers that can be adopted from the production method are limited, and in the case of the card method, there is a limit in reducing the fineness of the constituent fibers, and at least about 1.5 denier, Inferior in flexibility and furthermore, there is a problem that the papermaking method causes lint. Moreover, although these nonwoven fabrics have apertures, the apertures are fine, and therefore, in fields where high liquid permeability and air permeability are required, such as, for example, surface materials of sanitary materials. , Is difficult to use.

Meanwhile, the applicant has filed Japanese Patent Application No. 9-2306.
In No. 73, after providing a heat-fused area at intervals on a fiber web made of a composite-type long fiber, splitting and splitting the composite-type long fiber in a non-fused area outside the heat-fused area; In the non-fused area outside the fused area, the fiber composed of only the high melting point component and the fiber composed only of the low melting point component generated by the splitting of the composite type long fiber and the unsplit composite length that was not split An ultra-fine fiber non-woven fabric in which fibers are mixed together in a three-dimensional manner is proposed. This ultrafine fiber nonwoven fabric has ultrafine fibers as a main component in the non-fused area, and furthermore, since the components are mixed while being three-dimensionally entangled, it has such flexibility that it can be used as a surface material of, for example, a sanitary material. . However, although this nonwoven fabric has apertures, the apertures are fine and are insufficient in terms of liquid permeability and air permeability.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances and provides an ultrafine fiber nonwoven fabric having improved liquid permeability and air permeability. In particular, the present invention further improves the nonwoven fabric made of ultrafine fibers disclosed in Japanese Patent Application No. 9-230673, wherein the ultrafine fibers generated by splitting of the composite type long fibers in the non-fused area outside the fused area are substantially formed. Has sufficient tensile strength and dimensional stability by forming a typical three-dimensional confounding, and because it has openings formed by specific high-pressure liquid flow treatment, liquid permeability and air permeability are improved, An object of the present invention is to provide a nonwoven fabric which generates less fluff and is particularly suitable as a surface material of a sanitary material.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, in the present invention, a thermoplastic polymer component A is combined with a thermoplastic polymer component B which is incompatible with the polymer component A and has a melting point higher than the melting point of the polymer component A. A microfiber nonwoven fabric formed of a conjugated long fiber in which at least the polymer component A is exposed on the surface thereof, wherein the composite is formed by softening or melting only the component A in the conjugated long fiber. Fusion regions formed by fusion between the long fibers are provided at intervals, and non-fused regions outside the fusion regions include components generated by splitting of the composite long fibers. A
The fiber A consisting only of the fiber B, the fiber B consisting only of the component B produced by the splitting of the composite type filament and the undivided composite type filament that has not been split are mixed while substantially three-dimensionally entangled. The present invention is characterized in that an ultrafine fiber nonwoven fabric having openings is characterized in that an opening portion and an opening portion coexist.

[0006]

Next, the present invention will be described in detail.
First, the composite long fiber used in the present invention will be described. This composite type long fiber is a thermoplastic polymer component A
And a thermoplastic polymer component B which is incompatible with the polymer component A and has a melting point higher than the melting point of the polymer component A. And the polymer component A
Is exposed at least on the surface of the composite type long fiber. The reason why a polymer exhibiting thermoplasticity is adopted as the polymer component A is that the composite component long fibers are fused together by melting or softening of the polymer component A. Therefore, at least a part of the polymer component A must be exposed on the surface of the composite long fiber. Polymer component A
This is because if they are not exposed, they cannot be bonded to other composite type long fibers by fusion. Further, the polymer component B has a melting point higher than the melting point of the polymer component A, and is preferably 30 to 180 ° C higher, more preferably 40 to 160 ° C higher, and most preferably 50 to 160 ° C higher.
It has a 140 ° C higher melting point. The reason for this is that when heat and pressure are partially applied to the web composed of the composite-type long fibers to form a fusion zone between the composite-type long fibers by melting or softening the polymer component A having a low melting point, a high melting point is formed. The reason for this is to allow the polymer component B to maintain a fiber structure without melting or softening. If the difference between the melting points of both polymer components is the same,
When polymer component A is melted or softened, polymer component B
Is also easily softened or deteriorated, the fibrous structure of the composite long fiber collapses, the mechanical strength of the formed fused area is reduced, and the fiber is easily broken. In addition, the fused area is melted or softened to form a film, which makes it difficult to obtain a high-strength nonwoven fabric. On the other hand, if the difference in melting point between the two polymer components exceeds 180 ° C., it becomes difficult to produce the composite type long fiber itself by the composite melt spinning method. The melting points of the polymer components A and B are measured by the following method. That is, the temperature giving the extreme value of the melting absorption curve obtained by raising the temperature from room temperature at a rate of temperature rise of 20 ° C./min using DSC-7 manufactured by Perkin Elmer was defined as the melting point. Further, the polymer component A and the polymer component B
Must be incompatible polymers. this is,
This is because the affinity between the polymer component A and the polymer component B is reduced, and the component A and the component B are easily separated from each other at the joint surface during splitting. That is, it is for imparting the function of split splitting to the composite type long fiber. Further, it is necessary that both the component A and the component B are exposed on the surface of the composite long fiber.

Specific combinations of the polymer component A and the polymer component B (component A / component B) include polyamide-based polymer / polyester-based polymer, polyolefin-based polymer / polyester-based polymer, and polyolefin-based polymer. Polymer /
A polyamide polymer or the like can be employed. As the polyester-based polymer, polyethylene terephthalate, polybutylene terephthalate, a copolymer polyester containing these as a main component, or the like can be used.
Nylon 6, Nylon 4 as polyamide-based polymer
6, nylon 66, nylon 610 or copolymerized nylon containing these as a main component.
Polyolefin polymers include polypropylene, high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene or ethylene-
A propylene copolymer or the like can be employed. In addition,
In the component A or the component B, a slight amount of a third polymer component may be mixed as long as the melting point relationship between the two components and the releasability can be maintained. If desired, a lubricant, a pigment, a matting agent, a heat stabilizer, a light stabilizer, an ultraviolet absorber, an antistatic agent, a conductive agent, a heat storage agent, an antibacterial agent, and the like may be added.

As a method of combining the polymer component A and the component B in the composite type long fiber, any form may be used as long as it satisfies the above requirements. Specifically, it is preferable that the composite fibers are combined so that the cross section thereof is in the form shown in FIGS. Both the polymer component A and the polymer component B need to be exposed on the surface of the composite long fiber. In the figure, the shaded portion is the component B, and the scattered portion is the component A. In addition, the center part where neither the oblique line nor the scattered point in FIG. 2 is given may be hollow (hollow fiber),
Further, it may be formed of a polymer component other than the component A and the component B. Although the cross section of the composite type long fiber shown in FIGS. 1 to 4 is substantially circular in cross section and point symmetric, it is not limited thereto, and may be an asymmetric type with an irregular cross section. Of course. Although the quantitative ratio when the polymer component A and the component B are combined can be arbitrarily determined, generally, the component A / the component B = 20 to 80/80 to 20 (parts by weight). When the amount of the component A is less than 20 parts by weight, the bonding force between the composite type long fibers due to fusion decreases, and it tends to be difficult to impart sufficient tensile strength to the obtained nonwoven fabric. On the other hand, when the component A exceeds 80 parts by weight, the fusion between the composite type long fibers becomes intense, and the fusion area becomes a film-like form, or in extreme cases, a hole is formed, and the resulting nonwoven fabric is obtained. Tends to decrease the tensile strength of the steel.

[0009] The fineness of the single filament of the composite type filament employed in the present invention is also an item which can be arbitrarily determined, but is preferably 2 to 12 deniers, particularly preferably 2 to 1 denier.
More preferably, it is 0 denier. If the single-filament fineness of the composite type long fiber is less than 2 denier, the composite type long fiber tends to be too thin to be produced, and the productivity is reduced. On the other hand, if the single-fiber fineness exceeds 12 denier, the composite type long fiber tends to be too thick, so that a nonwoven fabric having a low basis weight and a good texture tends to be hardly obtained.

[0010] The above-mentioned composite type long fibers are used, and these are accumulated to form a fiber web. The production of the composite long fiber and the formation of the fiber web are preferably performed by the following methods. That is, first, a thermoplastic polymer component A such as the above-mentioned polyolefin-based polymer is prepared. Then, a thermoplastic polymer component B which is incompatible with the polymer component A and has a melting point higher than the melting point of the component A is prepared. Then, the components A and B are introduced into a melt spinning apparatus equipped with a composite spinneret, and a composite long fiber is obtained by a conventionally known composite melt spinning method. Polymer Component A in Composite Spinneret
When B and B are introduced, the components A and B must be exposed on the surface of the obtained composite long fiber.
In order to melt-spin the component A and the component B, they may be heated to a temperature 20 to 60 ° C. higher than their respective melting points. Therefore, when the melting point difference between component A and component B exceeds 180 ° C,
Component A is heated to a temperature much higher than its melting point due to the thermal effect of component B in a molten state, and component A may be thermally decomposed or deteriorated. When the spinning temperature is lower than the above temperature range, it is difficult to increase the spinning speed, and it is difficult to obtain a composite filament having a fineness. On the other hand, if the spinning temperature is higher than the above-mentioned temperature range, the fluidity of the component A and the component B is increased, and the yarn breakage tends to occur frequently during melt spinning. When the yarn breaks, the cut end becomes a ball-shaped lump, and the lump is mixed in the obtained non-woven fabric. As a result, the quality of the non-woven fabric tends to deteriorate. In addition, components A and B
When the fluidity of the spinning hole increases, the vicinity of the spinning hole becomes liable to be stained, and the spinning hole needs to be washed at regular intervals, and the spinning operability tends to decrease.

[0011] The melt-spun composite filament is then cooled and pulled and pulled by a pulling means such as an air sack.
The air sucker is usually referred to as an air jet, and is used to carry the fiber and draw the fiber by the suction and delivery of air. The group of composite type long fibers pulled by the air sucker is conveyed to the outlet of the air sucker while being stretched. Of course, a roll can be used instead of the pulling / taking by the air sucker, and in this case, a method of pulling by the air sucker following the pulling by the roll is preferable. The taken composite type long fiber is opened by an opening device provided at the outlet of the air sack. As the fiber opening method, a conventionally known method is employed, for example, a corona discharge method, a triboelectric charging method, or the like. Then, the opened composite type long fibers are accumulated on a moving collecting conveyor made of wire mesh or the like, and a fiber web is formed.

Next, heat is applied to a predetermined area of the fiber web in the thickness direction to form a fused area. That is, only the polymer component A of the composite type long fiber in that area is softened or melted to fuse the composite type long fibers with each other to form a fusion zone. The predetermined areas are provided at intervals and are arranged in the form of scattered points in the fiber web. In this predetermined area, heat is applied so that the temperature becomes substantially the same in the thickness direction. When heat is not applied over the thickness direction and is applied only to the front surface or the back surface of the fiber web, the component A of the composite long fiber does not sufficiently soften or melt in the intermediate layer of the fiber web, and the space between the composite long fibers is reduced. It is not preferable because it does not fuse sufficiently and the tensile strength and dimensional stability of the obtained nonwoven fabric cannot be improved. The area of the fusion zone, may be formed in a desired size in the fiber web, in Honmyo, in the range of 0.1 to 1.0 mm ^2, its density or fused area density 4 It is preferable that the number is 80 points / cm ² . This fusion zone can be formed at a desired ratio in the fiber web. In the present invention, the ratio of the area of the total fusion zone to the total area of the obtained nonwoven fabric is 2 to 5%.
It is preferable to form them at a ratio of 0%. When the ratio of the area of the fusion zone to the entire area of the nonwoven fabric is less than 2%, mechanical properties such as tensile strength and dimensional stability of the nonwoven fabric tend to decrease. On the other hand, when the ratio of the area of the fused area to the entire area of the nonwoven fabric exceeds 50%, the area where the composite type long fibers are fused increases, and the flexibility of the obtained nonwoven fabric tends to be excessively reduced. In addition, the splitting rate is not improved when splitting the composite type long fiber in the splitting process to be performed later.

As a method for applying such heat, for example, an embossing device composed of an embossing roll (which is an uneven roll; the same applies hereinafter) and a smoothing roll or an embossing device composed of a pair of embossing rolls is used. What is necessary is just to heat the embossing roll and press the convex part against the fiber web. The projections are provided on the embossing roll surface in a scattered, linear, curved, or the like. The shape of the tip surface of each convex portion of the embossing roll does not necessarily have to be circular, but may be elliptical, rhombic, triangular, T-shaped,
Arbitrary shapes such as a linear shape, a curved shape, and a well shape can be adopted. At this time, the embossing roll is preferably heated to a temperature equal to or lower than the melting point of the polymer component A. When the embossing roll is heated to a temperature higher than the melting point of the component A, the component A is melted even in an area other than the convex portion pressed by the fiber web, and the area of the fusion area is larger than a predetermined ratio, There is a tendency that the flexibility of the obtained nonwoven fabric is reduced. The fusing zone forming temperature (embossing roll temperature) is a temperature lower than the melting point of the polymer component A, and preferably 5 to 30 ° C. lower than the melting point of the component A. If the fusion zone is formed at a temperature higher than the melting point, the fiber web sticks to the embossing roll device and the operability is remarkably deteriorated. When the temperature for forming the fusion zone is close to the melting point of the component A, the fusion becomes strong, and the dimensional stability of the nonwoven fabric is improved. Further, in the high-pressure liquid flow treatment that follows, in the non-fused area outside the fusion area, the fiber A consisting of only the component A generated by the split splitting of the composite type long fiber, which is generated by the split splitting of the composite type long fiber. In forming a three-dimensional entanglement in the fiber B consisting only of the component B and the unsplit composite long fiber that has not been split, the fused area retains its shape without collapsing, and thus the obtained nonwoven fabric Is
It has excellent mechanical properties such as tensile strength and dimensional stability. On the other hand, if an attempt is made to form a fusion zone at a temperature lower than the melting point of the polymer component A by 30 ° C. or more, the fusion zone will be in a state of temporary fusion maintaining the fiber morphology, The fusion zone collapses into a fibrous material, and the fiber A is composed of only the component A generated by splitting the composite type long fiber, and the component B is generated by splitting the composite type long fiber.
Since both the fiber B consisting of only and the unsplit composite long fibers that were not split and split have a high degree of freedom,
Although the obtained nonwoven fabric has improved flexibility, mechanical properties such as tensile strength and dimensional stability are reduced. Note that the fusion zone may be formed using an ultrasonic welding device including an uneven roll and an ultrasonic transmission device. The ultrasonic welding device irradiates a predetermined area of the fiber web with ultrasonic waves, and melts the polymer component A by frictional heat between the multiple long fibers in the predetermined area.

As described above, a fiber fleece in which the conjugate long fibers are fused to each other in a predetermined area is obtained. Then, the fiber fleece is subjected to a splitting treatment. As the splitting method, a method using a needle punch, a method using a kneading action by a high-pressure liquid flow such as a liquid flow dyeing machine, or a method such as a buckling compression method can be adopted. In the method using the needle punch, the composite type long fiber of the fiber fleece is split and split to produce a fiber A consisting of only the polymer component A and a fiber B consisting of only the polymer component B. A three-dimensional confounding is formed. Also, in the method utilizing the kneading action by the high-pressure liquid flow, three-dimensional interlacing between split fibers is performed together with split splitting of the composite type long fiber of the fiber fleece, but this entangling is performed by using a needle punch. And high-pressure liquid flow treatment. On the other hand, in the buckling compression method, when a fiber fleece is introduced into a roll, a buckling compression method in which a fiber fleece is bent by increasing an introduction speed higher than a derivation speed is basically adopted. Specifically, a method of introducing a fiber fleece between a pair of rolls, a method of introducing a fiber fleece between one roll and a presser plate, and an upper presser plate and a lower presser after being introduced into one roll. A method of introducing a fiber fleece between the plate and the plate (comb-shaped holding plate) may be used. As a device for applying such a buckling compression method, it is preferable to employ a microcreper machine manufactured by Mike Rex, a camfight machine manufactured by Uenoyama Kiko Co., or the like. FIG. 5 shows a method of introducing a fiber fleece 5 between a single roll 1 and a presser plate 2 in an example of a microcreper machine manufactured by Microtex.

In the buckling compression method described above, the conjugate long fiber is split and split in the split area (the area outside the fusion zone) to which this treatment has been applied, and the fiber A comprising the polymer component A alone and the fiber A A fiber B consisting only of the united component B is produced, and a part of the undivided composite filament remains, and substantially no three-dimensional entanglement is formed between these fibers. The reason for this is that, in the case of this treatment method, a kinetic energy which is not high enough to form three-dimensional entanglement between fibers, such as a method using a needle punch or a method utilizing a kneading action, is not provided. This means that the split fibers have a high degree of freedom, and a desired entangled state can be designed when the next high-pressure liquid flow treatment is performed to form three-dimensional entanglement between the fibers. Therefore, when manufacturing the nonwoven fabric of the present invention, it is preferable to employ such a buckling compression method. The splitting rate in the splitting area subjected to the buckling compression treatment is preferably 70% or more, and more preferably 90% or more. When the splitting rate is less than 70%, fibers A and B
May decrease and the flexibility may not be sufficiently improved. Here, the splitting rate is measured by the following measuring method. That is, any ten locations of the fiber web subjected to the buckling compression treatment are selected, and the cross section in the splitting area is magnified 100 times and a scanning electron microscope photograph is taken. Next, randomly select 30
The filament of this book is selected, the splitting rate is calculated by the following equation (1), and the average value of the obtained values is defined as the splitting rate of the fiber web. Splitting rate (%) = (30 / N) × 100 (1) In the formula (1), N is a filament composed of the polymer component A and a filament composed of the polymer component B when it is assumed that the fiber is completely divided. Is the total number of all filaments.

As described above, a fiber fleece in which the conjugate long fibers are split in the non-fused area outside the fused area is obtained. Then, the fiber fleece is subjected to a high-pressure liquid flow treatment. In the high-pressure liquid flow treatment, for example, an apparatus in which a large number of injection holes having a hole diameter of 0.05 to 1.5 mm, particularly 0.1 to 0.4 mm are arranged in a row or a plurality of rows at a hole interval of 0.05 to 5 mm. Is used. A water stream, that is, a high-pressure liquid stream is injected from the injection hole at a high pressure, and collides with a fiber fleece placed on the porous support member. Thereby, the fiber A consisting only of the component A generated by the split splitting of the composite type long fiber present in the non-fused area outside the fusion zone, and the component A generated only by the split splitting of the composite type long fiber The fibers B and the undivided composite long fibers that are not split are three-dimensionally entangled with each other. The arrangement of the injection holes is arranged in a row in a direction (lateral direction) perpendicular to the traveling direction (machine direction) of the fiber fleece. Room temperature or hot water can be used as the high-pressure liquid flow. The distance between the injection hole and the fiber fleece is preferably 10 to 150 mm. If this distance is less than 10 mm, the formation of the nonwoven fabric obtained by this treatment will be disturbed. On the other hand, if this distance exceeds 150 mm, the impact force when the liquid stream collides with the fiber fleece will decrease, resulting in three-dimensional confounding. Tend not to be formed sufficiently. The processing pressure of this high-pressure liquid flow is determined by the manufacturing method and the required characteristics of the nonwoven fabric, but is generally 20 to 2
A high pressure liquid stream of 00 kg / cm ² G is preferably ejected.
In addition, depending on the basis weight of the fleece to be processed, etc., within the range of the processing pressure, it is possible to obtain a nonwoven fabric which is bulky and excellent in flexibility when the processing pressure is low, and the fibers between fibers when the processing pressure is high. A nonwoven fabric having a high degree of entanglement and a dense form can be obtained. High pressure liquid flow pressure 20kg
If it is less than / cm ² G, three-dimensional entanglement is not sufficiently formed, and the obtained nonwoven fabric is likely to have fluff when used. On the other hand, the pressure of the high-pressure liquid flow is 200 kg / cm ² G
If it exceeds, the fibers are cut in an extreme case by impact with water pressure, and the resulting nonwoven fabric tends to have fluff on the surface due to the fiber cut ends. In addition, after performing the high-pressure liquid flow treatment from one side of the fiber fleece, by subsequently inverting the entangled fiber web and performing the high-pressure liquid flow treatment again, to obtain a nonwoven fabric in which the fibers on both sides are densely entangled. Can be.

As the porous support member for carrying the fiber fleece used in the high-pressure liquid flow treatment, a mesh screen made of a wire mesh or a synthetic resin or the like, which has a high-pressure liquid flow penetrating the fiber web, is employed. . What is important here is the condition of the mesh screen, that is, the wire diameter, the number of wires existing per unit width in the vertical and horizontal directions, that is, the number of gauges (lines / inch), and the woven texture of the screen. By appropriately selecting these conditions, a specific opening can be formed in the nonwoven fabric after the treatment. That is, by applying a high-pressure liquid flow treatment to the fiber fleece by using a mesh screen under specific conditions, only the component A generated by the split splitting of the composite long fiber is applied to the non-fused area outside the fused area. A, a fiber B consisting of only the component B generated by splitting the composite type long fiber
In addition, it is possible to simultaneously form a part where the undivided composite long fibers that have not been split and mixed are substantially three-dimensionally entangled and an opening part at the same time. The open area formed in the non-fused area of the fiber fleece by such high-pressure liquid flow treatment has an area of 1 to 7 mm per single hole.
² and having a porosity of 20 to 50%. When this area is less than 1 mm ² per single hole, it is difficult to impart sufficient liquid permeability and air permeability to the obtained nonwoven fabric, while 7 m
If it exceeds m ² , for example, even if an attempt is made to use it as a surface material of a sanitary material, the aperture is too large to function as a surface material. Further, if the porosity is less than 20% or more than 50%, it is not suitable as a surface material of a sanitary material.

After the high-pressure liquid flow treatment, excess moisture is removed from the treated nonwoven fabric. When removing the excess moisture, a known method may be employed. For example,
The excess water is mechanically removed to some extent using a squeezing device such as a mangle roll, and the remaining water is subsequently removed using a drying device such as a hot air circulating dryer of a suction band type.

As described in detail above, the nonwoven fabric of the present invention
It has a fusion zone and a non-fusion zone where the composite filaments are fused to each other. In the non-fusion zone, the composite filaments are split and split by buckling compression treatment, and the polymer component A Fiber A consisting of only component A, fiber B consisting of only polymer component B is produced, and fiber A consisting of component A alone, fiber B consisting of component B alone, and undivided fibers that have not been split by high-pressure liquid flow treatment A portion where the composite type long fibers are mixed while being substantially three-dimensionally entangled, and an opening portion coexist. This nonwoven fabric has the following advantages as compared with splitting by a conventional high-pressure liquid flow treatment method and formation of a three-dimensional interlaced portion and an open portion. That is, the impact is also given by subjecting the composite type filament to high-pressure liquid flow treatment, thereby splitting the composite type filament and forming a three-dimensional entanglement. Fibers split and split or composite type long fibers are strongly entangled three-dimensionally by a large impact force, that is, a large kinetic energy. Therefore,
In the divided area, the fibers are entangled with each other to form a dense state, so that not only flexibility but also bulkiness are greatly reduced. On the other hand, the nonwoven fabric of the present invention, in which the three-dimensional entanglement is formed by the high-pressure liquid flow and the opening is formed following the splitting by the buckling compression treatment, is performed in the non-fused area without collapsing the fused area. The composite type long fiber is sufficiently split, and the three-dimensionally entangled and coexisting portions of the fibers in the non-fused area coexist. The mechanical properties such as dimensional stability are maintained, and the liquid permeability and air permeability can be improved by forming openings. In the present invention, the splitting by the buckling compression treatment and the three-dimensional entanglement and the formation of the opening by the high-pressure liquid flow are individually performed, so that the degree of the splitting, the entanglement and the opening can be controlled individually. Not even.

The fineness of the fiber A comprising only the polymer component A produced by splitting the composite type long fiber is 0.05
Preferably it is ~ 4.0 denier. On the other hand, the fineness of the fiber B composed of only the polymer component B is 0.05 to
Preferably it is 0.8 denier. The fineness of the fiber A and the fiber B may be the same, but the fiber A is often relatively thick (about 1.5 to 3 times the fineness of the fiber B) in many cases. This is because the composite long fiber as shown in FIG. 1 or FIG. 4, that is, the polymer component B is divided into a large number on the surface of the composite long fiber, and the polymer component A is the composite long fiber. This is because, in some cases, a composite type long fiber that is arranged without being divided at the center of the fiber is employed.

The fiber length of this composite type long fiber is so long as to be infinite, and therefore, this composite type long fiber extends over the split area and the fusion area. Then, in the fusion zone, the composite filaments are bonded to each other by fusion of the polymer component A, are not split, and exist in the original composite filament state.

Although the basis weight of the nonwoven fabric of the present invention can be determined arbitrarily, it is generally from 10 to 25.
It is about 0 g / m ² . In particular, when used as a surface material for sanitary materials, the weight is preferably about 15 to 40 g / m ² .
As described above, the nonwoven fabric of the present invention has mainly been described as being mainly used as a surface material of a sanitary material. However, it is needless to say that this nonwoven fabric is used for various other uses. .

Next, the present invention will be specifically described based on examples. In addition, the measurement of each characteristic in an Example was performed by the following method. Melting point of polymer (° C.): The temperature at which the maximum value of the melting endothermic peak was measured at a heating rate of 20 ° C./min using a differential scanning calorimeter DSC-2 manufactured by Perkin Elmer was defined as the melting point. did. Intrinsic viscosity of polyester: Determined by a conventional method using an equal weight mixed solution of phenol and tetrachloroethane as a solvent. Single yarn fineness (denier) of the nonwoven web constituting fibers after splitting: A cross-sectional photograph of the sample was taken using an electron microscope, the cross-sectional area was calculated, and the density was corrected for. Nonwoven fabric weight (g / m ² ): Ten pieces of sample pieces each having a sample length of 10 cm and a sample width of 5 cm were prepared from the nonwoven fabric in a standard state (temperature: 20 ° C., relative humidity: 65%), and after reaching equilibrium moisture, The weight (g) of each sample piece was weighed, and the average of the obtained values was converted per unit area (m ² ) to obtain the basis weight (g / m ² ) of the nonwoven fabric. Tensile strength of nonwoven fabric (kg / 5cm width): JIS L-1
096 according to the stripping method. That is, ten sample pieces each having a sample length of 20 cm and a sample width of 5 cm are prepared from the nonwoven fabric, and the mechanical direction (hereinafter abbreviated as MD) and the lateral direction (hereinafter abbreviated as CD) of the nonwoven fabric for each sample piece. About, using a constant speed elongation type tensile tester Tensilon RTM-500 manufactured by Toyo Baldwin Co., Ltd., gripping interval 10 cm,
The maximum load was measured by elongating at a tensile speed of 20 cm / min, and the average of the obtained maximum load values (kg / 5 cm width) was defined as the tensile strength (kg / 5 cm width) of the nonwoven fabric. Tensile elongation (%) of non-woven fabric: Elongate each sample in the same manner as in measuring the tensile strength of non-woven fabric to determine the elongation (%) at the maximum load. Degree (%). Aperture area (mm ² ) of nonwoven fabric: Ten sample pieces each having a sample length of 1 inch and a sample width of 1 inch were prepared from the nonwoven fabric, and 20 sample holes were randomly selected by a projector for each sample piece. The area (mm ² ) was determined, and the average of the obtained values was defined as the open area (mm ² ) of the opening of the nonwoven fabric. Perforation rate (%) of perforated portion of non-woven fabric: The total area (mm ² ) of perforated portions present in one square inch of the non-woven fabric was obtained, and the obtained value was converted to per unit area (mm ² ). The opening ratio (%) of the opening portion of the nonwoven fabric was determined. Nonwoven fabric total hand (g): JIS L1096E
According to the handle ometer method. That is, after preparing three sample pieces each having a sample length of 20 cm and a sample width of 20 cm from the nonwoven fabric, “Fuaymeter” Model FM-2 type No. No. manufactured by DAIEI KEIKI Co., Ltd. 82-004
, Two points were measured in the machine direction and the lateral direction of the nonwoven fabric for each sample piece under the condition of a slit width of 10 mm, and the total value obtained was used as the total hand of the nonwoven fabric (hereinafter referred to as T).
Abbreviated as H. ) (G). Evaluation of soft feeling: The soft feeling of the nonwoven fabric was evaluated by a sensory test according to the following five grades. That is, grade 5 was soft, grade 4 was slightly soft, grade 3 was normal, grade 2 was slightly hard, and grade 1 was evaluated as hard. Evaluation of drape property: The drape property of the nonwoven fabric was evaluated by a sensory test according to the following five grades. That is, grade 5 was good, grade 4 was somewhat good, grade 3 was normal, grade 2 was slightly poor, and grade 1 was poor. Liquid permeability: The liquid permeability of the nonwoven fabric was evaluated by visual observation of the permeability immediately after dropping of water droplets, in the following three grades. That is, the third grade was evaluated as good, the second grade as normal, and the first grade as poor.

[0024]

【Example】

Example 1 A high-density polyethylene having a melting point of 132 ° C. and a melt index (measured according to the method described in ASTM D1238 (E)) of 20 g / 10 min as a thermoplastic polymer component A, Polyethylene terephthalate having a melting point of 256 ° C. and an intrinsic viscosity of 0.70 when dissolved in a mixed solution of an equal amount of phenol and tetrachloroethane was prepared as the plastic polymer component B, and the polymer component A and the polymer were prepared. Composite melt spinning was performed using Component B. At the time of melt spinning, a composite spinning apparatus provided with a spinneret having an 8-leaf type spinning hole for division so as to obtain a composite long fiber having a cross-sectional shape as shown in FIG. 1 was used. Then, composite melt spinning was performed so that the single hole discharge amount was 1.30 g / min and the discharge amount ratio of component A / component B, that is, the composite ratio was 1.0 / 1.4. The melting temperature was 230 ° C. for the component A and 285 ° C. for the component B. The spinning temperature was 285 ° C. After the composite melt spinning, the composite type long fiber is pulled through an air sucker disposed at a position 150 cm below the spinneret, and the speed is 4000 m.
/ Min. The cross section of the composite type long fiber thus obtained was as shown in FIG. 1, and the single fiber fineness was 3.0 denier. Subsequently, the drawn composite type long fiber group was opened by corona discharge, and deposited on a moving conveyor net to form a fiber web. This fiber web was introduced between an embossing roll heated to a temperature of 122 ° C and a smooth roll heated to a temperature of 122 ° C. As a result, the area of the fiber web in contact with the protrusion of the embossing roll is heated in the thickness direction,
The polyethylene of the composite type long fibers softened, and the composite type long fibers were fused together. The fusing areas corresponding to the projections of the embossing roll were arranged in a scattered manner, and the total area was 12% with respect to the total surface area of the nonwoven fabric.

Next, in the fiber fleece obtained as described above, that is, in the fusion zone, the composite filaments are bonded to each other, and in the non-fusion zone, the composite filaments are simply accumulated. Using a buckling compression apparatus (Microcreper I manufactured by Macrecus Co., Ltd.) as shown in FIG. 5, the processing speed is 100 m / min, the temperature of the flat supply roll 1 is 50 ° C., the pressing plate 2 is Pressure of 3kg
/ Cm ² was subjected to buckling compression processing. FIG.
Among them, 5 is a fiber fleece and 6 is the obtained nonwoven fabric. The non-woven fabric after the buckling compression process has a single-fiber fineness of 0.3 denier and an ultra-fine polyethylene terephthalate fiber of 0.3 denier produced by splitting of the composite type long fiber in the splitting area which is a non-fused area. 1.3 denier polyethylene fibers were mixed and accumulated in a non-entangled state. on the other hand,
In the fusion area (non-split area), the composite type long fibers were bonded to each other by fusion of polyethylene. The splitting rate of the composite long fiber in the splitting area was 90%.

Next, the non-woven fabric after the buckling compression processing was loaded on a 5-mesh wire net and subjected to a high-pressure liquid flow treatment. In the high-pressure liquid flow treatment, the injection hole with a hole diameter of 0.12 mm
mm high-pressure liquid flow treatment device, and using water at room temperature as a liquid, from the position of 80 mm above the non-woven fabric after the buckling compression processing, 5 times under the condition of a water flow pressure of 80 kg / cm ² G, went. After this treatment, the obtained nonwoven fabric was subjected to removal of excess moisture and drying treatment to obtain a nonwoven fabric of the present invention having a basis weight of 25 g / m ² . In the non-fused area (split area), the obtained nonwoven fabric has a portion where ultrafine polyethylene terephthalate fibers, polyethylene fibers and unsplit composite long fibers that have not been split are mixed while being three-dimensionally entangled. The hole and the hole coexisted. Table 1 shows the evaluation results of the open area and the open area ratio, the tensile strength and the tensile elongation, the total hand, the softness, the drape property, the liquid permeability and the like of this nonwoven fabric.

Example 2 A high-pressure liquid flow treatment was carried out in the same manner as in Example 1 except that a 10 mesh wire net was used and the water flow pressure was 30 kg / cm ² G, and the basis weight of the present invention was 25 g / m ² . A non-woven fabric was obtained. Table 1 shows the evaluation results of the open area and the open area ratio, the tensile strength and the tensile elongation, the total hand, the softness, the drape property, the liquid permeability and the like of this nonwoven fabric.

[0028] In performing Example 3 high-pressure liquid jet treatment, using a wire mesh of 3.5 mesh screen, and the water pressure in the same manner as in Example 1 except that the 100 kg / cm ² G, of the basis weight 25 g / m ² The nonwoven fabric of the invention was obtained. Opening area and opening rate of this nonwoven fabric, tensile strength and tensile elongation, total hand, soft feeling and drapability,
Table 1 shows the evaluation results of the liquid permeability and the like.

Example 4 A nonwoven fabric of the present invention having a basis weight of 37 g / m ² was obtained in the same manner as in Example 1 except that the fiber web forming conditions were changed.
The opening area and opening ratio, tensile strength and tensile elongation of this nonwoven fabric,
Table 1 shows the evaluation results of the total hand, soft feeling, drape property, liquid permeability and the like.

Comparative Example 1 A non-woven fabric having a basis weight of 25 g / m ² was obtained in the same manner as in Example 1 except that a 3-mesh wire gauze was used and a water flow pressure was set to 100 kg / cm ² G when performing a high-pressure liquid flow treatment. Was.
The opening area and opening ratio, tensile strength and tensile elongation of this nonwoven fabric,
Table 1 shows the evaluation results of the total hand, soft feeling, drape property, liquid permeability and the like.

Comparative Example ² A nonwoven fabric having a basis weight of 25 g / m ² was obtained in the same manner as in Example 1 except that a wire mesh of 15 mesh was used when applying a high-pressure liquid flow treatment, and the water flow pressure was 30 kg / cm ² G. Was.
The opening area and opening ratio, tensile strength and tensile elongation of this nonwoven fabric,
Table 1 shows the evaluation results of the total hand, soft feeling, drape property, liquid permeability and the like.

Comparative Example 3 A non-woven fabric having a basis weight of 25 g / m ² was obtained in the same manner as in Example 1 except that a 10 mesh wire net was used and a water jet pressure was set to 30 kg / cm ² G when performing a high-pressure liquid flow treatment. Was.
The opening area and opening ratio, tensile strength and tensile elongation of this nonwoven fabric,
Table 1 shows the evaluation results of the total hand, soft feeling, drape property, liquid permeability and the like.

Comparative Example 4 A nonwoven fabric having a basis weight of 13 g / m ² was obtained in the same manner as in Example 1 except that the conditions for forming the fiber web were changed. Table 1 shows the evaluation results of the open area and the open area ratio, the tensile strength and the tensile elongation, the total hand, the softness, the drape property, the liquid permeability and the like of this nonwoven fabric.

Comparative Example 5 A nonwoven fabric having a basis weight of 22 g / m ² was obtained in the same manner as in Example 1 except that the high-pressure liquid flow treatment was not performed. Table 1 shows the evaluation results of the non-woven fabric such as tensile strength and tensile elongation, total hand, softness, drapability, and liquid permeability.

[0035]

[Table 1]

As is clear from the above results, Example 1
The nonwoven fabrics of Nos. 4 to 4 have sufficient tensile strength and dimensional stability, and in the non-fused area (split area), the part where the constituent fibers are mixed three-dimensionally entangled and the open part coexist. Thus, the resin has sufficient flexibility, and has specific openings, so that liquid permeability and gas permeability are improved. On the other hand, the nonwoven fabric of Comparative Example 1 was excellent in flexibility and liquid permeability, but was inferior in tensile strength and dimensional stability due to too large aperture. Further, the nonwoven fabrics of Comparative Examples 2 and 3 had sufficient tensile strength and dimensional stability, but were poor in flexibility and liquid permeability due to too small aperture. Furthermore, the nonwoven fabric of Comparative Example 4 was excellent in softness and drape, but had too low basis weight and poor tensile strength and dimensional stability as well as formation. The nonwoven fabric of Comparative Example 5 was inferior in liquid permeability because there was no opening in the non-fused area (split area).

[0037]

The nonwoven fabric of the present invention has a fused area and a non-fused area, that is, a split area, in which the ultrafine fibers A and the fibers developed by splitting the composite filaments are present. B and non-split non-split composite type long fibers that coexist in a three-dimensionally entangled and co-existing area and co-exist with a sufficient tensile strength and dimensional stability Since it has water permeability and has openings formed by a specific high-pressure liquid flow treatment, it has improved liquid permeability and air permeability, and is particularly suitable as a surface material for sanitary materials.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a cross section of a composite type long fiber according to the present invention.

FIG. 2 is a view showing an example of a cross section of a composite type long fiber according to the present invention.

FIG. 3 is a view showing an example of a cross section of a composite type long fiber according to the present invention.

FIG. 4 is a view showing an example of a cross section of a composite long fiber according to the present invention.

FIG. 5 is an enlarged side view showing an example of an apparatus used for buckling compression processing in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Roll of buckling compression processing machine 2 Press plate of buckling compression processing machine 5 Fiber fleece of unsplit fiber processing 6 Nonwoven fabric after split processing

Claims (6)

[Claims] 1. A composite of a thermoplastic polymer component A and a thermoplastic polymer component B which is incompatible with the polymer component A and has a melting point higher than the melting point of the polymer component A. A microfiber nonwoven fabric formed of a conjugated long fiber in which at least the polymer component A is exposed on the surface thereof, wherein the composite type is formed by softening or melting only the component A in the conjugated long fiber. A fusion area formed by fusion between the long fibers is provided at intervals, and a non-fused area outside the fusion area has a component A generated by splitting of the composite long fiber.
The fiber A consisting only of the fiber B, the fiber B consisting only of the component B produced by the splitting of the composite type filament and the undivided composite type filament that has not been split are mixed while substantially three-dimensionally entangled. A microfiber nonwoven fabric having an aperture, wherein a portion having a hole and an aperture portion coexist. 2. The microfiber nonwoven fabric having pores according to claim 1, wherein the difference in melting point between the thermoplastic polymer component A and the thermoplastic polymer component B is 30 to 180 ° C. 3. The microfine fiber having an aperture according to claim 1, wherein the single fiber fineness of the fiber A is 0.05 to 4.0 denier and the single fiber fineness of the fiber B is 0.05 to 0.8 denier. Fiber non-woven fabric. 4. The microfiber nonwoven fabric having pores according to claim 1, wherein the ratio of the fusion zone to the total area of the nonwoven fabric is 2 to 50%. 5. The area of an opening is 1 to 7 mm ² per single hole,
5. The microfiber nonwoven fabric having pores according to claim 1, wherein the pore rate is 20 to 50%. 6. The microfiber nonwoven fabric having pores according to claim 1, wherein the basis weight is 15 to 40 g / m ² .