Composite non-woven fabric

Abstract

To provide a conjugated nonwoven fabric in which dust emission is suppressed.SOLUTION: A pulp fiber web is laminated on and integrated with a spun-bonded nonwoven fabric to form a conjugated nonwoven fabric. Basis weight of the spun-bounded nonwoven fabric is 7 to 30 g / m2. Basis weight of the pulp fiber web is 30 to 100 g / m2. Weight component ratio between the spun-bonded nonwoven fabric and the pulp fiber web is 40 / 60 to 10 / 90 (wt.%). Ventilation resistance value of the spun-bonded nonwoven fabric is 0.13 kPa s / m or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a composite nonwoven fabric obtained by hydraulically entangling a pulp fiber web and a spunbond nonwoven fabric.

Background Art

[0002] A composite nonwoven fabric made of a pulp fiber web and a spunbond nonwoven fabric has both the liquid absorbency based on pulp fibers and the strength based on the spunbond nonwoven fabric, so it is widely used in various applications such as industrial wipes such as wipers and personal wipes such as hand towels and towels.

[0003] For example, as disclosed in Patent Document 1, after overlapping a pulp fiber web and a spunbond nonwoven fabric, they are integrated by a hydraulic entanglement treatment in which a high-pressure water jet (water flow) is sprayed. Here, since the spunbond nonwoven fabric is excellent in strength, it functions as a backing layer of the manufactured composite nonwoven fabric. On the other hand, the pulp fiber web has an excellent liquid absorption function. Therefore, such a composite nonwoven fabric can be provided to consumers as an excellent composite nonwoven fabric that combines the advantages of a pulp fiber web having good absorbency for both aqueous and oily liquids and a spunbond nonwoven fabric having excellent strength.

[0004] Regarding the spunbond nonwoven fabric (referred to as a nonwoven continuous filament support in Patent Document 1) used in Patent Document 1 and the like, for example, those obtained by subjecting a synthetic resin such as polypropylene to a spunbond treatment are widely adopted. In the spunbond treatment, spun resin fibers are connected by a plurality of fused portions (hereinafter, fusion points) fused by heat treatment. Thereby, the spunbond nonwoven fabric exhibits its own sheet strength and maintains its outer shape.

[0005] In Patent Document 1 mentioned above, an example is given of manufacturing a pulp fiber web by diverting the sheet manufacturing technology using the wet papermaking method. However, a pulp fiber web can be manufactured by the dry airlaid method. When the wet papermaking method is adopted, large-scale equipment similar to that of conventional paper manufacturing is required. However, the airlaid method is excellent in that it can simplify the equipment and reduce costs.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In conventional composite nonwoven fabrics, it has been confirmed that dust-like fine (about 5 μm or less) fibers such as "dust generation" and "lint" are generated when used as wipes. Fine fibers are generated by the treatment during the production of the pulp web or during the water flow entanglement, and these fibers remain in the nonwoven fabric and fall off during use, which is considered to be the cause of the above-mentioned dust generation (generation of fine fibers). Such dust generation reduces the product value, so its elimination is desired.

[0008] Therefore, an object of the present invention is to provide a composite nonwoven fabric in which dust generation is suppressed.

Means for Solving the Problems

[0009] The above object is a composite nonwoven fabric in which a pulp fiber web is laminated and integrated on a spunbond nonwoven fabric, and the basis weight of the spunbond nonwoven fabric is 7 to 30 g / m 2 , and the basis weight of the pulp fiber web is 30 to 100 g / m 2and the weight composition ratio of the spunbond nonwoven fabric and the pulp fiber web is 40 / 60 to 10 / 90 (wt%), and the air permeability resistance value of the spunbond nonwoven fabric is 0.13 kPa·s / m or less, which can be achieved by a composite nonwoven fabric characterized by this.

[0010] The spunbond nonwoven fabric can be one type selected from the group consisting of nylon, vinylon, polyester, acrylic, polyethylene, polypropylene, and polystyrene, or a mixture of two or more types.

[0011] And the spunbond nonwoven fabric is formed including a plurality of fusion points connecting the spun resin fibers, the area ratio per unit area of the fusion points is 7 to 15%, the area of one fusion point is 0.10 to 0.50 mm 2 , and the number of fusion points per unit area is 10 to 200 per cm 2 and it is preferable that it is like this.

[0012] The shape of the fusion point is preferably one shape selected from the group consisting of circular, elliptical, and square.

Advantages of the Invention

[0013] According to the present invention, a composite nonwoven fabric with suppressed dust generation can be provided.

Brief Description of the Drawings

[0014]

Figure 1

Modes for Carrying Out the Invention

[0015] Hereinafter, the composite nonwoven fabric according to the present invention will be described. As described above, as a facility for supplying a pulp fiber web, the dry airlaid method is excellent in that it can suppress costs. In the case of the dry airlaid method, there is also known a facility that recovers the fibers that have passed through the wire of a laminating device that gradually laminates pulp fibers and recirculates (returns) them to the laminating device side. Therefore, although it is conceivable to deploy a dust collector in the facility to remove the fine fibers described above, this would increase the equipment cost. Therefore, it was desired to suppress dust generation (generation of fine fibers) in the product by designing the material itself that constitutes the composite nonwoven fabric. Under the above circumstances, the inventors of the present invention have intensively studied composite nonwoven fabrics, and by setting the weight composition ratio of the spunbond nonwoven fabric and the pulp fiber web, the basis weight of the spunbond nonwoven fabric and the pulp fiber web, and the air permeability resistance value of the spunbond nonwoven fabric within a specific range, it has been found that dust generation can be suppressed, and the present invention has been achieved.

[0016] The basis weight of the spunbond nonwoven fabric is 7 to 30 g / m 2 , and the basis weight of the pulp fiber web is preferably 30 to 100 g / m 2 . Further, it is more preferable that the basis weight of the spunbond nonwoven fabric is 10 to 18 g / m 2 and the basis weight of the pulp fiber web is 48 to 71 g / m 2 . Also, the weight composition ratio of the spunbond nonwoven fabric to the pulp fiber web, i.e., spunbond nonwoven fabric / pulp fiber web, is preferably 40 / 60 to 10 / 90 (wt%).

[0017] And the air permeability resistance value of the spunbond nonwoven fabric is set to 0.13 kPa·sec / m or less, and more preferably 0.10 kPa·sec / m or less. The larger this air permeability resistance value, the more difficult it is to ventilate. As the air permeability resistance value exceeds 0.13 kPa·sec / m and the numerical value increases, more dust generation is confirmed. In conventional composite nonwoven fabrics, the air permeability resistance value of the spunbond nonwoven fabric employed has not been considered. The air permeability resistance value (kPa·sec / m) of the spunbond nonwoven fabric can be measured, for example, using an air permeability tester (KES-F8) manufactured by Kato Tech Co., Ltd. In the definition of JIS L1096 Air Permeability Method A (Frazee method), when the pressure difference reaches 125 Pa, the air permeability is defined with the flow rate passing through it as Q, and the air permeability: Q = [cc / (cm 2 sec)]. In the above air permeability tester, a constant flow rate V [m 3 / (m 2 sec)] is passed through, and the pressure difference ΔP [KPa] at this time is measured, and the air permeability resistance R value (kPa·sec / m) is obtained from R = ΔP / V.

[0018] The spunbond nonwoven fabric used in the composite nonwoven fabric according to the present invention can be one selected from the group consisting of nylon, vinylon, polyester, acrylic, polyethylene, polypropylene, and polystyrene, or a mixture of two or more kinds. It is preferable to use polypropylene.

[0019] The above spunbond nonwoven fabric is formed including a plurality of fusion points connecting the spun resin fibers, and the area ratio per unit area of the fusion points is 7 to 15%, more preferably 10 to 15%. Also, the area of one fusion point is 0.10 to 0.50 mm 2 , more preferably 0.10 to 0.36 mm 2 , and the number of fusion points per unit area is preferably 10 to 200 pieces / cm 2 . Also, the shape of the fusion point is not particularly limited, but it is preferably selected from the group consisting of a circle, an ellipse, and a square. By appropriately and comprehensively setting the area ratio, the area of one, the number per unit area, and the shape of the fusion points arranged on the spunbond nonwoven fabric described here within the above ranges, a spunbond nonwoven fabric with an air permeability resistance value of 0.13 kPa·sec / m or less as described above can be obtained.

[0020] Hereinafter, a manufacturing apparatus suitable for manufacturing the composite nonwoven fabric according to the present invention will be described with reference to FIG. 1. The schematic configuration of the manufacturing apparatus 1 for the composite nonwoven fabric will be described. The manufacturing apparatus 1 shown in Fig. 1 is provided with an airlaid apparatus 2 for supplying a pulp fiber web to the upstream side, a spunbond nonwoven fabric supply apparatus 3 for supplying a spunbond nonwoven fabric, and a suction apparatus 4. The suction apparatus 4 is arranged so as to face the lower side of the airlaid apparatus 2. In the web conveyance direction TD, downstream of these apparatuses 2, 3, 4, in order from the upstream side, a water jet apparatus 5 for injecting a water jet for performing a water entanglement treatment, a suction apparatus 6 for performing a dehydration treatment, and a drying apparatus 7 are arranged. A winding apparatus 8 for winding up the continuously manufactured composite nonwoven fabric WP is provided downstream of the drying apparatus 7.

[0021] The airlaid apparatus 2 includes a defibrator 21 for defibrating raw material pulp RP in which fibers are densely packed and in a sheet form into pulp fibers, and a duct 22 for conveying the defibrated pulp fibers PF to an airlaid hopper 23 with a blower (not shown).

[0022] Also, an airlaid hopper 23 is arranged downstream of the duct 22. Inside this airlaid hopper 23, the defibrated pulp fibers descend while being dispersed, and are designed to gradually accumulate at a stacking position 24 set on the lower surface to form a pulp fiber web PFW. As described above, the airlaid apparatus 2 is a device and equipment that can supply a pulp fiber web in a dry manner, and can suppress the equipment cost compared to a device that manufactures a pulp fiber web in a wet manner by applying the wet papermaking method. Further, in the airlaid apparatus 2, from the defibration to the dispersion and descent of the pulp, it is a closed space, and the entry of foreign matter is prevented. Therefore, compared with the case of supplying a pulp fiber web by the wet papermaking method, the entry of foreign matter can be suppressed to an overwhelmingly low level.

[0023] Below the above-mentioned lamination position 24, a suction device 4 is arranged opposite. More specifically, the suction device 4 has a suction part 42 on the upper surface of the device main body 41, and the suction part 42 is set with respect to the lamination position 24 so as to apply a suction force (negative pressure) to the pulp fiber web PFW. In addition, in FIG. 1, the case where the airlaid hopper 23 and the suction device main body 41 are arranged one by one in a single stage to form the pulp fiber web PFW is illustrated. However, it is not limited to this, and according to the basis weight (grammage) and production speed of the above-mentioned pulp fiber web PFW, the airlaid hopper 23 and the suction device main body 41 may be changed to an arrangement with two or more multi-stages.

[0024] In addition, a conveying wire 43 for web conveyance is arranged around the suction device 4. The conveying wire 43 is configured such that the pulp fiber web PFW on which the pulp fibers PF are deposited at the lamination position 24 can be placed thereon and is arranged to convey this to the downstream side. However, the pulp fiber web PFW is not directly placed on the conveying wire 43. This will become clear in the following description. The conveying wire 43 is formed in a mesh form such that the suction force of the suction part 42 reaches the opposite side (upper side).

[0025] Below the above-mentioned airlaid device 2 and upstream of the suction device 4, a spunbond nonwoven fabric supply device 3 is arranged. In this spunbond nonwoven fabric supply device 3, a previously prepared spunbond nonwoven fabric SW is set in a roll shape. That is, as described above, the spunbond nonwoven fabric SW with an air permeability resistance value set lower than a predetermined value is wound up during production and formed into a roll shape, and this is drawn out from the spunbond nonwoven fabric supply device 3 and conveyed onto the above-mentioned conveying wire 43 to the above-mentioned lamination position 24.

[0026] The above-described pulp fiber web PFW is placed on the spunbond nonwoven fabric SW located at the lamination position 24. At this time, at the lamination position 24, the suction force by the suction portion 42 of the suction device 4 passes through the conveyor wire 43 and acts on the spunbond nonwoven fabric SW and the pulp fiber web PFW above it. Therefore, a preliminary laminate PWeb (laminated web) in which the spunbond nonwoven fabric SW and the pulp fiber web PFW are laminated is conveyed downstream. When the preliminary laminate PWeb is formed as described above, by controlling the supply amount of the pulp fiber web PFW onto the spunbond nonwoven fabric SW, the basis weight of the pulp fiber web PFW contained in the composite nonwoven fabric manufactured by this apparatus is, for example, 30.0 to 100.0 g / m 2 and is set to be. And the basis weight of the spunbond nonwoven fabric SW is preferably, for example, 7.0 to 30.0 g / m 2 By appropriately adjusting the conveyance speed of the pulp fiber web and the supply amount per unit time of the pulp fiber web PFW, and checking the basis weight of the pulp fiber web PFW of the manufactured composite nonwoven fabric, the basis weight and the weight composition ratio of the spunbond nonwoven fabric and the pulp fiber web can be set to be within a desired range. The conveyance speed of the pulp fiber web is preferably, for example, 150 to 300 m / min.

[0027] The above-described preliminary laminate PWeb is maintained in a laminated state by being suction-compressed by the suction force of the suction device 4. At this time, the fibers of the upper pulp fiber web PFW are in a dense state. However, if the preliminary laminate PWeb is conveyed and introduced into the downstream water flow intersection device 5 as it is, there is a risk that a part of the pulp fibers PF will be lifted up by the water jet (high-pressure water flow). Therefore, in this manufacturing apparatus 1, a sandwiching roller 28 for stabilizing the placement state of the pulp fiber web PFW on the spunbond nonwoven fabric SW by sandwiching the preliminary laminate PWeb from above and below, and a prewetting apparatus 30 for imparting moisture to prevent fiber scattering are provided upstream of the water entanglement apparatus 5. The prewetting apparatus 30 preferably includes a spray nozzle 31 for spraying a water mist from above the preliminary laminate PWeb and a suction apparatus 32 for applying a suction force from the lower side of the preliminary laminate PWeb (i.e., the lower surface of the pulp fiber web PFW).

[0028] In addition, in FIG. 1, the case where the prewetting apparatus 30 is provided as a new apparatus in front of the water entanglement apparatus 5 as described above is illustrated, but it is not limited thereto. For a plurality of sets composed of a water jet head 51 and a suction apparatus 52 described later included in the water entanglement apparatus 5, a design change may be made to divert the set located at the head as the above-described prewetting apparatus 30. In this case, it may be adjusted so that a low-pressure water mist is sprayed from the head water jet head 51. In the case of the water entanglement apparatus 5 where the number of sets of the water jet head 51 and the suction apparatus 52 sufficient for performing the water entanglement process is ensured, utilizing the head water jet head 51 and the suction apparatus 52 as the prewetting apparatus as described above is effective in suppressing the equipment cost of the apparatus.

[0029] Then, in the water entanglement apparatus 5, the entanglement of pulp fibers is promoted by spraying a high-pressure water jet onto the preliminary laminate PWeb that has undergone the processing of the sandwiching roller 28 and the prewetting apparatus 30, which are the pretreatment sections. Thereby, the integration of the pulp fiber web PFW layer located on the upper side and the spunbond nonwoven fabric SW layer located on the lower side is promoted (water entanglement process). The water entanglement apparatus 5 exemplarily shown in FIG. 1 has water jet heads 51 arranged in multiple stages (four stages are illustrated in FIG. 1) along the conveyance direction TD. In FIG. 1, the state of the nozzles provided in the water jet head 51 extending in the direction perpendicular to the conveyance direction TD (the web width direction CD) is not shown, but a plurality of water jet nozzles are arranged at appropriate positions in the width direction. The hole diameter φ of the water jet nozzles is preferably 0.06 to 0.15 mm. Further, the interval between the water jet nozzles is preferably 0.4 to 1.0 mm.

[0030] When performing the above-described water flow entanglement treatment, it is desirable to set the water pressure in consideration of the basis weights of the pulp fiber web PFW and the spunbond nonwoven fabric SW. For example, it is preferably selected in the range of 1 to 30 MPa.

[0031] And a suction device 52 is disposed so as to face the water jet head 51. While spraying the high-pressure water jet from the water jet head 51 onto the pulp fiber web PFW located on the upper side, the suction force of the suction device 52 is applied to the lower side of the spunbond nonwoven fabric SW located on the lower side. By the cooperative action of the water jet head 51 and the suction device 52, it is presumed that a state in which the pulp fibers on the pulp fiber web PFW side enter the lower spunbond nonwoven fabric SW or a state in which the spunbond nonwoven fabric SW is penetrated and reaches the opposite side is formed. By this action, the integration of the two layers is promoted.

[0032] A conveyance wire 55 is also provided in the water flow entanglement device 5. The conveyance wire 55 receives the preliminary laminate PWeb downstream of the pretreatment units 28 and 30 and conveys it into the water flow entanglement device 5. The conveyance wire 55 is disposed so as to pass between the water jet head 51 and the suction device 52 of the water flow entanglement device 5 from the upstream side to the downstream. Therefore, the preliminary laminate PWeb conveyed on the conveyance wire 55 receives more water flow entanglement treatment as it moves downstream in the conveyance direction TD, and when it exits the water flow entanglement device 5, a composite nonwoven fabric can be obtained by sufficient entanglement treatment between the upper pulp fiber web PFW layer and the lower spunbond nonwoven fabric SW layer. When the water flow entanglement treatment is performed in this way, since the spunbond nonwoven fabric SW adopted here is designed to have a lower air permeability resistance value than the conventional one as described above, it is easier for the high-pressure water jet to penetrate, and the generated fine fibers are easily washed away by the drainage, so that the retention inside the composite nonwoven fabric is suppressed. As a result, a composite nonwoven fabric with suppressed dust generation can be obtained.

[0033] In the case of the composite nonwoven fabric immediately after exiting the water flow entanglement device 5, it is in a wet state, and the bonding between pulp fibers and the like is not sufficiently established. Therefore, as shown in FIG. 1, on the downstream side of the water flow entanglement device 5, a suction device 6 and a drying device 7 for performing a dehydration treatment for sucking and removing the moisture remaining in the pulp fiber web and then a drying treatment to complete the production of the composite nonwoven fabric WP are provided. By performing the dehydration treatment and the drying treatment by the suction device 6 and the drying device 7 in the latter stage of the production of the composite nonwoven fabric WP in this way, the composite nonwoven fabric can be efficiently produced, and a dried composite nonwoven fabric can be produced without applying a large external pressure to the composite nonwoven fabric after the water flow entanglement.

[0034] And, a drying device 7 is further installed downstream of the suction device 6, and the composite nonwoven fabric WP is dried. The drying device 7 here preferably employs a non-compressive dryer, preferably an air-through dryer. In FIG. 1, the rotatable dryer body 71 of the air-through dryer is a cylindrical body, and a large number of through holes are provided on its peripheral surface, and hot air heated by a heat source (not shown) is preferably sucked from the outer periphery of the dryer body toward the center side. The composite nonwoven fabric WP continuously produced in this way is wound around the roll 81 of the winding device 8 after drying. As described above, the manufacturing apparatus 1 can efficiently manufacture the composite nonwoven fabric with suppressed dust generation according to the present invention.

[0035] (Example) Hereinafter, examples and comparative examples of the composite nonwoven fabric of the present invention will be described. For Examples 1 to 5 of the composite nonwoven fabric where the basis weight, area of the fusion point, area ratio, number, shape, and air permeability resistance value of the spunbond (SB) nonwoven fabric used in the composite nonwoven fabric, the basis weight of the pulp fiber web, and the weight composition ratio between the spunbond (SB) and the pulp fiber web are as shown in Table 1, and for Comparative Examples 1 to 3 as shown in Table 2, the dust generation (generation of fine fibers) state of the composite nonwoven fabric was confirmed. Regarding the wiping property as a wiper, there was no problem with any of the composite nonwoven fabrics.

[0036] The dust generation amount was evaluated as follows. The fine fibers were divided into those with a length of 0.3 to 0.5 μm or less, 0.5 to 1.0 μm or less, 1.0 to 2.0 μm or less, 2.0 to 5.0 μm or less, and those exceeding 5.0 μm, and the number of generated fibers was confirmed. Specifically, using the "Optical Scattering Type Automatic Particle Counter" manufactured by Lion Corporation, the number (number of fibers) of fine fibers per unit area (m 2 ) of the nonwoven fabric was counted, and these were totaled to confirm the total number. A composite nonwoven fabric with a dust generation amount exceeding 40,000 pieces / m 2 per unit area of the nonwoven fabric was evaluated as defective. It was confirmed that from Examples 1 to 5, the lower the air permeability resistance value, the more dust generation can be suppressed. For example, when the air permeability resistance value of the spunbond nonwoven fabric was 0.128 (Example 1), the dust generation amount was 34,805. When the air permeability resistance value was further lowered to 0.091 (Example 3), the dust generation amount was 12,636, and it was confirmed that it could be further greatly suppressed. On the other hand, the air permeability resistance value of the spunbond nonwoven fabric in Comparative Example 1 was 0.162, and the air permeability resistance value of the spunbond nonwoven fabric in Comparative Example 2 was 0.150. The respective dust generation amounts greatly exceeded 40,000 pieces / m 2 per unit area.

[0037]

Table 1

[0038]

Table 2

[0039] Although the description of the embodiments has been completed above, it goes without saying that the present invention is not limited to the above embodiments and can be implemented with various modifications without departing from the gist thereof.

Explanation of Reference Numerals

[0040] 1 Manufacturing apparatus for composite nonwoven fabric 2 Airlaid apparatus 3 Spunbond nonwoven fabric supply apparatus 4 Suction apparatus 5 Water entanglement apparatus 6 Suction apparatus 7 Drying apparatus 8 Winding apparatus 21 Fiberizer 22 Duct 23 Airlaid hopper 24 Laminating position 28 Clamping roller 30 Pre - wetting apparatus 31 Spray nozzle 32 Suction apparatus 41 Suction apparatus main body 42 Suction part 43 Conveyor wire 51 Water jet head 52 Suction apparatus 55 Conveyor wire SW Spunbond nonwoven fabric PF Pulp fiber PFW Pulp fiber web PWeb Preliminary laminate (laminated web) WP Composite nonwoven fabric TD Transport direction

Claims

1. A composite non-woven fabric in which a pulp fiber web is laminated and integrated on a spunbond non-woven fabric, The spunbond non-woven fabric includes a plurality of fusion points connecting the spun resin fibers, The basis weight of the spunbond non-woven fabric is 7 to 30 g / m ２ , the basis weight of the pulp fiber web is 30 to 100 g / m ２ and the weight composition ratio of the spunbond non-woven fabric to the pulp fiber web is 40 / 60 to 10 / 90 (wt%), and the air permeability resistance value of the spunbond non-woven fabric is 0.13 kPa·s / m or less, The area ratio per unit area of the fusion points is 7 to 15%, the area of one fusion point is 0.10 to 0.50 mm 2, the number of fusion points per unit area is 185 to 200 pieces / cm 2, and the shape of the fusion points is square. A composite non-woven fabric characterized by this.

2. The spunbond non-woven fabric is one selected from the group consisting of nylon, vinylon, polyester, acrylic, polyethylene, polypropylene, and polystyrene, or a mixture of two or more thereof. The composite non-woven fabric according to claim 1, characterized by this.

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