Composite nonwoven fabric and its manufacturing method

Abstract

To provide a composite nonwoven fabric which is less bulky while keeping good water absorption performance and wiping property, and further moderate rigidity.SOLUTION: There is provided a composite nonwoven fabric in which a pulp fiber web is laminated on a spunbond nonwoven fabric to be integrally formed, where a basis weight is 52.0-130.0 g / m2, thickness is 0.13-0.35 mm, density is 0.25-0.60 g / cm3, a water absorption amount per area is 280 g / m2 or more and a water absorption amount per density is 1.2 g / cm3 or more.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

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

[0003] For example, as disclosed in Patent Document 1, a pulp fiber web and a spunbond nonwoven fabric are layered and then integrated by a hydroentanglement process in which a high-pressure water jet (water flow) is sprayed onto them. Here, the spunbond nonwoven fabric has excellent strength and functions as a backing layer for the composite nonwoven fabric produced. Meanwhile, the pulp fiber web has excellent liquid absorption properties. 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 that has good absorbency for both aqueous and oil-based liquids and a spunbond nonwoven fabric that has excellent strength. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 2533260 Summary of the Invention [Problem to be solved by the invention]

[0005] The above composite nonwoven fabric is manufactured by supplying a pulp fiber web manufactured by a dry or wet process onto a spunbond nonwoven fabric and performing hydroentanglement. In the composite nonwoven fabric manufactured in this manner, the pulp fibers on the spunbond nonwoven fabric are oriented in various directions (three-dimensional random) due to the influence of the water flow during hydroentanglement. Then, the composite nonwoven fabric is formed through a drying process. Therefore, the composite nonwoven fabric manufactured has some of the pulp fibers aligned in the thickness direction protruding. If the fibers aligned in the thickness direction in this manner are dried as is, the completed composite nonwoven fabric will be bulky.

[0006] Although the bulky composite nonwoven fabrics described above have excellent water absorption performance, the bulkiness becomes a problem when folding (in two, four, six, etc.) the fabric into a product shape for commercialization. In other words, the bulkier the product, the higher the material costs and logistics costs become. One possible solution to this problem is to reduce the relative amount of the pulp fiber web in order to reduce the bulk (make the fabric more compact). However, this approach reduces the water absorption performance of the nonwoven fabric and makes it difficult to wipe off the fabric.

[0007] An object of the present invention is to provide a composite nonwoven fabric that has reduced bulk while maintaining water absorption performance, wiping ability, and appropriate rigidity, and also to provide a manufacturing apparatus capable of manufacturing such a composite nonwoven fabric. [Means for solving the problem]

[0008] The above object is to provide a composite nonwoven fabric having a pulp fiber web laminated and integrated onto a spunbond nonwoven fabric, the basis weight of which is 52.0 to 130.0 g / m 2 , thickness 0.13~0.35mm, density 0.25~0.60g / cm 3 The water absorption per unit area is 280g / m 2 or more, and the water absorption per density is 1.2g / cm 3 This can be achieved by the composite nonwoven fabric having the above features.

[0009] It is preferable that the drop water absorbency is within 3.0 seconds and the wet Taber value is 5 or more. The pulp fiber web has a basis weight of 40.0 to 100.0 g / m 2 and the weight ratio of the spunbond nonwoven fabric to the pulp fiber web is preferably 40 / 60 to 10 / 90 (wt %).

[0010] The basis weight of the spunbond nonwoven fabric is 7.0 to 30.0 g / m 2 The spun resin fibers are connected to each other by a plurality of fusion points, and the area of ​​the fusion points is 0.10 to 0.50 mm 2 The area ratio of the fusion points per unit area is 7 to 20%, and the number of fusion points is 10 to 150 / cm 2 It is preferable that:

[0011] The material of the spunbond nonwoven fabric is preferably one or a mixture of two or more selected from the group consisting of nylon, vinylon, polyester, acrylic, polyethylene, polypropylene and polystyrene.

[0012] The pulp fiber web is preferably made of bleached kraft pulp fibers from a softwood selected from the group consisting of radiata pine, slash pine, southern pine, lodgepole pine, spruce and Douglas fir.

[0013] The above object can also be achieved by a method for producing a composite nonwoven fabric as described above, which comprises at least a hydroentanglement step of promoting integration of the pulp fiber web and the spunbond nonwoven fabric to obtain a laminate, and a drying step of drying the laminate after the hydroentanglement step, and further comprises a thermal calendering step of passing the laminate between calender rolls while heating and pressurizing the laminate after the drying step.

[0014] In the thermal calendaring process, it is preferable to use a main roll and a backing roll having a roll equivalent diameter of 100 to 400 mm calculated by the formula (roll equivalent diameter) = (main roll diameter) x (backing roll diameter) / {(main roll diameter) + (backing roll diameter)}, set the conveying speed to 150 to 280 m / min, the gap between the rolls to 0 to 0.3 mm, and the roll nip pressure to 1.0 to 8.0 MPa. Furthermore, the temperature of the rolls is preferably set to 40 to 200°C. Effect of the Invention

[0015] According to the present invention, it is possible to provide a composite nonwoven fabric that maintains water absorption performance, wiping ability, and appropriate rigidity while suppressing bulkiness, and also to produce such a composite nonwoven fabric. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a diagram showing a manufacturing apparatus for a composite nonwoven fabric. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, a composite nonwoven fabric according to one embodiment of the present invention will be described. The inventors of the present application have conducted extensive research into composite nonwoven fabrics and have found that the basis weight (g / m 2 ), thickness (mm), density (g / cm 3 ), and water absorption per unit area (g / m 2 ) and water absorption per density (g / cm 3 It was confirmed that a composite nonwoven fabric designed so that the surface roughness (T) is within a predetermined range has the water absorption and wiping properties required for products, while also being able to suppress bulkiness, and this led to the present invention. The total water absorbency per area (TWA) was measured by cutting the composite nonwoven sheet into a 76mm x 76mm square to prepare a sample, measuring its dry weight, immersing the sample in distilled water for 2 minutes, and then hanging the sample in a steam-saturated container (100% RH) in a stretched state with one corner of the sample at the top, supporting this top and the two adjacent corners, and leaving it for 30 minutes to determine the weight after draining. The measured value was then measured over 1m of the sample. 2 Water absorption per unit (g / m 2 ) can be calculated by converting it into the water absorption per density (g / cm 3 ) is the water absorption per unit area (g / cm 2 ) by the thickness of the nonwoven fabric (cm). Water absorption per unit area (g / m 2 ) is the water absorption per unit area of ​​a composite nonwoven fabric and is a general indicator of water absorption performance. In addition, the water absorption per density (g / cm 3 ) is the water absorbency per unit volume of a composite nonwoven fabric, and a high value indicates that the nonwoven fabric has a high water absorption capacity despite its thinness. The above-mentioned composite nonwoven fabric can be produced by subjecting the fabric to a heat calendar treatment after the drying step.

[0018] Furthermore, the composite nonwoven fabric according to the present invention is preferably designed so that the drop absorbency and wet Taber value are within predetermined ranges, and the basis weight of the pulp fiber web, the weight ratio of the spunbond nonwoven fabric to the pulp fiber web (spunbond nonwoven fabric (SB) / pulp fiber web (Pulp)), and the basis weight and fusion point form of the spunbond nonwoven fabric are also preferably designed to be within predetermined ranges. The above factors and their preferred ranges relating to the composite nonwoven fabric will be explained below.

[0019] In the composite nonwoven fabric according to the present invention, the basis weight is 52.0 to 130.0 g / m 2 , preferably 60.0 to 85.0 g / m 2, the thickness is 0.13 to 0.35 mm, preferably 0.20 to 0.30 mm, and the density is 0.25 to 0.60 g / cm 3 , preferably 0.30 to 0.45 g / cm 3 Furthermore, the water absorption per unit area is 280 g / m 2 More than 300g / m 2 The water absorption per density is 1.2g / cm 3 More than 1.5 g / cm, preferably 1.5 g / cm 3 It is set to above. A composite nonwoven fabric formed so that the basis weight, thickness, density, water absorption amount per area, and water absorption amount per density are within the above ranges can be made to have reduced bulk while maintaining water absorption performance and wiping ability.

[0020] Furthermore, the composite nonwoven fabric according to the present invention preferably has a water drop absorbency of 3.0 seconds or less and a wet Taber value of 5 times or more. The drop water absorbency was measured in accordance with the water absorption rate test specified in JIS S3104, in which 0.1 mL of water was dropped, and the time (seconds) from when the water drop reached the surface of the test piece until the mirror reflection of the test piece disappeared was measured. The wet Taber value is measured by using a Taber tester specified in JIS L1096 to attach a wetted sample to a rotating horizontal disk, and apply a pair of friction wheels (H-18) made of abrasive grains under a specified load (4.9N) to check the wear resistance. The Taber value is the number of rotations of the disk until the hole in the sheet due to wear becomes 13 mm.

[0021] The basis weight of the pulp fiber web is, for example, 40.0 to 100.0 g / m 2 The weight ratio of the spunbond nonwoven fabric to the pulp fiber web is preferably, for example, 40 / 60 to 10 / 90 (wt%). A composite nonwoven fabric in this range is excellent not only in water absorption and wiping properties, but also in shape stability. The basis weight of the spunbond nonwoven fabric is, for example, 7.0 to 30.0 g / m 2In addition, the spunbond nonwoven fabric is formed to include a plurality of fusion points that bond the spun resin fibers, and the area of ​​each of the fusion points is preferably 0.10 to 0.50 mm. 2 The area ratio of the fusion points per unit area is 7 to 20%, and the number of fusion points is 10 to 150 / cm 2 Such a spunbonded nonwoven fabric has an appropriate rigidity and is suitable for use as a spunbonded nonwoven fabric to be combined with a pulp fiber web to form a composite nonwoven fabric. The shape of the fusion points is not particularly limited and may be circular, elliptical, polygonal, etc. Whether the composite nonwoven fabric has become a product with appropriate rigidity due to the spunbond nonwoven fabric can be determined by evaluating the shape stability, strength (ease of tearing) and "stiffness" of the composite nonwoven fabric.

[0022] The spunbond nonwoven fabric is preferably made of one or a mixture of two or more materials selected from the group consisting of nylon, vinylon, polyester, acrylic, polyethylene, polypropylene, and polystyrene. Among these, polypropylene is preferably used. Furthermore, it is preferable to use the pulp fiber web formed from bleached kraft pulp fibers of a softwood selected from the group consisting of radiata pine, slash pine, southern pine, lodgepole pine, spruce and Douglas fir.

[0023] The process for producing the composite nonwoven fabric of the present invention described above will be described below. The composite nonwoven fabric of the present invention can be efficiently produced by a predetermined thermal calendaring process after a drying process. Here, the main configuration of the production device for producing the composite nonwoven fabric WP, which is the premise, will be described, and then the thermal calendaring device and the thermal calendaring process will be described.

[0024] 1, a composite nonwoven fabric manufacturing apparatus 1 is provided with an airlaid device 2 on the upstream side, a spunbond supplying device 3 that supplies a spunbond nonwoven fabric, and a suction device 4. The suction device 4 is disposed below the airlaid device 2 so as to face it. In the web transport direction TD, downstream of these devices 2, 3, and 4, there are arranged, in this order from the upstream side, a hydroentanglement device 5 that sprays water jets for hydroentanglement treatment, a suction device 6, and a drying device 7. Downstream of the drying device 7, there is further provided a winding device 8 for winding up the composite nonwoven fabric WP that is continuously produced. The manufacturing apparatus 1 is further provided with a thermal calendering device CA between the drying device 7 and the winding device 8 for subjecting the dried nonwoven fabric WP to a thermal calendering treatment (calendering treatment while heating).

[0025] Starting from the upstream side, the airlaid device 2 includes a defibrator 21 that defibrates raw pulp RP, which is a sheet-like material made of densely packed fibers, into pulp fibers, and a duct 22 that is equipped with a blower (not shown) and transports the defibrated pulp fibers PF to an airlaid hopper 23.

[0026] In addition, an airlaid hopper 23 is disposed downstream of the duct 22. Inside this airlaid hopper 23, the pulp fibers in a defibrated state descend while being dispersed, and are designed to gradually pile up at a stacking position 24 set on the lower surface to form a pulp fiber web PFW. A suction device 4 is disposed facing the lower side of the stacking position 24. More specifically, the suction device 4 has a suction section 42 on the upper surface of an apparatus main body 41, and the suction section 42 is set with respect to the stacking position 24 so as to apply a suction force (negative pressure) to the pulp fiber web PFW. 1 shows an example in which the pulp fiber web PFW is formed by arranging the airlaid hopper 23 and the suction device main body 41 in a single stage. However, the present invention is not limited to this, and the airlaid hopper 23 and the suction device main body 41 may be arranged in two or more stages depending on the basis weight (basis weight) and production speed of the pulp fiber web PFW.

[0027] A transport wire 43 for transporting the web is disposed around the suction device 4. The transport wire 43 is disposed so that the pulp fiber web PFW on which the pulp fibers PF are accumulated at the stacking position 24 can be placed and transports the web downstream. However, the pulp fiber web PFW is not placed directly on the transport wire 43. This will become clear from the explanation given later. The conveying wire 43 is formed in an open mesh shape so that the suction force of the suction portion 42 extends to the opposite side (upper side).

[0028] A spunbond supplying device 3 is disposed below the airlaid device 2 and upstream of the suction device 4. A roll of spunbond nonwoven fabric SW that has been prepared in advance is set in this spunbond supplying device 3. The spunbond nonwoven fabric SW is pulled out from the spunbond supplying device 3 and transported to the layering position 24 on the transport wire 43 described above. As the spunbond nonwoven fabric SW, it is preferable to use a web of continuous filaments of a synthetic resin formed by a spunbonding method.

[0029] The above-mentioned pulp fiber web PFW is placed on the spunbond nonwoven fabric SW located at the stacking position 24. At this time, the suction force by the suction section 42 of the suction device 4 passes through the conveying wire 43 at the stacking position 24 and acts on the spunbond nonwoven fabric SW and the pulp fiber web PFW thereon. Thus, the preliminary laminate PWeb in which the spunbond nonwoven fabric SW and the pulp fiber web PFW are stacked is conveyed downstream.

[0030] The above-mentioned 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 transported and fed into the downstream hydroentangling device 5 in this state, there is a risk that a part of the pulp fibers PF will be blown up by the water jet (high-pressure water flow). Therefore, in the present manufacturing apparatus 1, there are provided clamping rollers 28 for sandwiching the preliminary laminate PWeb from above and below to stabilize the placement state of the pulp fiber web PFW on the spunbond nonwoven fabric SW, and a pre-wetting device 30 for applying moisture to prevent the fibers from scattering upstream of the hydroentangling device 5. The pre-wetting device 30 preferably includes a spray nozzle 31 for spraying water mist from above the preliminary laminate PWeb, and a suction device 32 for applying suction force from the underside of the preliminary laminate PWeb (i.e., the underside of the pulp fiber web PFW). 1 shows an example in which the pre-wetting device 30 is provided as a new device before the hydroentanglement device 5 as described above, but the present invention is not limited to this. The design of the hydroentanglement device 5 may be modified so that the first set of a plurality of sets each consisting of a water jet head 51 and a suction device 52 (described later) is used as the pre-wetting device 30. In this case, adjustments may be made so that low-pressure water mist is sprayed from the first water jet head 51. In the case of a hydroentanglement device 5 that has a sufficient number of sets of water jet heads 51 and suction devices 52 to perform the hydroentanglement treatment, using the leading water jet head 51 and suction device 52 as a pre-wetting device as described above is effective in reducing equipment costs.

[0031] Then, in the hydroentangling device 5, entangling of the pulp fibers is promoted by spraying a high-pressure water jet onto the preliminary laminate PWeb that has been treated by the clamping rollers 28 and the pre-wetting device 30, which are the pre-treatment section. This promotes integration of the pulp fiber web PFW layer located on the upper side with the spunbond nonwoven fabric SW layer located on the lower side. The hydroentangling device 5 exemplarily shown in FIG. 1 has water jet heads 51 arranged in multiple stages (four stages are shown in FIG. 1) along the conveyance direction TD. 1 does not show the nozzles provided on the water jet head 51 extending in the direction perpendicular to the conveying direction TD (the width direction of the web), but multiple water jet nozzles are arranged at appropriate positions in the width direction. The hole diameter φ of the water jet nozzle is preferably 0.06 to 0.15 mm. The interval between the water jet nozzles is preferably 0.4 to 1.0 mm.

[0032] The water pressure during the hydroentanglement treatment is desirably set in consideration of the basis weights of the pulp fiber web PFW and the spunbond web SW, and is preferably selected within the range of, for example, 1 to 30 MPa.

[0033] A suction device 52 is disposed opposite the water jet head 51. A high-pressure water jet from the water jet head 51 is sprayed onto the pulp fiber web PFW located on the upper side, while 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. It is presumed that the cooperative action of the water jet head 51 and the suction device 52 creates a state in which the pulp fibers on the pulp fiber web PFW side penetrate into the spunbond nonwoven fabric SW on the lower side, or penetrate through the spunbond nonwoven fabric SW to reach the opposite side. This action promotes integration of the two layers.

[0034] The hydroentangling device 5 is also provided with a conveying wire 55. The conveying wire 55 receives the preliminary laminate PWeb downstream of the pre-treatment units 28 and 30, and conveys it into the hydroentangling device 5. The conveying wire 55 is provided so as to pass between the water jet head 51 and the suction device 52 of the hydroentangling device 5 from the upstream side to the downstream side. Therefore, the preliminary laminate PWeb transported on the transport wire 55 undergoes more hydroentanglement treatment as it moves downstream in the transport direction TD, and by the time it leaves the hydroentanglement device 5, sufficient entanglement treatment is achieved between the upper pulp fiber web PFW layer and the lower spunbond nonwoven fabric SW layer. Immediately after leaving the hydroentangling device 5, the nonwoven fabric is in a wet state, and the bonds between the pulp fibers etc. are not yet sufficiently established.

[0035] 1, a suction device 6 and a dryer 7 are provided downstream of the hydroentanglement device 5 to remove residual moisture from the web by suction and then dry the web to complete the production of the composite nonwoven fabric WP. By carrying out dehydration and drying using the suction device 6 and the dryer 7 in this manner at the latter stage of the production of the composite nonwoven fabric WP, the nonwoven fabric can be produced efficiently, and by drying the hydroentangled nonwoven fabric without applying a large external pressure to the nonwoven fabric, a bulky nonwoven fabric can be produced as described above. The suction device 6 is, for example, of a vacuum type and dehydrates the nonwoven fabric after hydroentanglement. The drying device 7 is preferably a non-compression type 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 number of through holes are provided on its peripheral surface, so that hot air heated by a heat source (not shown) is sucked from the outer periphery of the dryer body toward the center.

[0036] Conventionally, a continuously produced composite nonwoven fabric WP has generally been wound around a roller 81 of a winding device 8, but in the manufacturing apparatus shown in FIG. 1, a thermal calendar device CA is disposed between the drying device 7 and the winding device 8 as a post-processing device. A pair of plain-surfaced calendar rolls (not shown) are arranged inside the thermal calendar device CA, and the composite nonwoven fabric WP is clamped and transported between them with a predetermined range of roll nip pressure (clamping pressure). There is no limitation on the material of each calender roll as long as the outer peripheral surface is formed to be flat, but it is preferable that both are steel plain rolls made of metal. A heater is disposed inside at least one of the calender rolls so that a thermal calendering process can be performed.

[0037] The thermal calendering conditions for the thermal calendering device CA are set, for example, so that the roll temperature is 40 to 200°C, more preferably 100 to 150°C, the roll gap is 0 to 0.3 mm, more preferably 0.1 to 0.2 mm, and the roll nip pressure applied to the composite nonwoven fabric WP passing between the rolls is 1.0 to 8.0 MPa, more preferably 2.5 to 5.0 MPa. The roll transport speed is desirably set to 150 to 280 m / min, more preferably 170 to 220 m / min.

[0038] The pair of metal rolls are arranged in a horizontal position so as to overlap one above the other, and the dried composite nonwoven fabric passes between them. The upper one is the main roll and the lower one is the receiving roll. The main roll and the backing roll are desirably designed so that the roll equivalent diameter calculated by the formula (roll equivalent diameter) = (main roll diameter) x (backing roll diameter) / {(main roll diameter) + (backing roll diameter)} is 100 to 400 mm, more preferably 150 to 350 mm. The roll equivalent diameter here is based on the literature presented by AV Lyons et al. (1990 TAPPI Finishing and Converting, p. 5), and is an index of the strength of the calendar treatment applied to the composite nonwoven fabric.

[0039] For example, if the roll equivalent diameter is less than 100 mm, the conveying speed is faster than 280 m / min, the gap is greater than 0.3 mm, the nip pressure is less than 1.0 MPa, or the roll temperature is lower than 40°C, the pressure and heat energy applied to the surface of the composite nonwoven fabric will be too small, reducing the effect of narrowing the spaces between the fibers and making it difficult to suppress bulk. Conversely, if the roll equivalent diameter is greater than 400 mm, the conveying speed is slower than 150 m / min, the nip pressure is greater than 8.0 MPa, the temperature is greater than 200°C, etc., the pressure and heat energy applied to the surface of the composite nonwoven fabric will be too large, causing the surface of the composite nonwoven fabric to harden, resulting in a decrease in thickness and an increase in density. This will result in a hard, paper-like feel, making the wiper less comfortable to use. In addition, there may be cases where a portion of the spunbond nonwoven fabric melts due to heat and is transferred to the roll surface. When the above-mentioned heater is disposed inside either the upper main roll or the lower backing roll, it is preferable to dispose it inside the upper main roll, because for convenience of the apparatus, the upper side is the pulp fiber web PFW layer, and it is more effective to heat the pulp fiber web PFW layer in order to suppress the bulk.

[0040] In the composite nonwoven fabric manufacturing apparatus shown in FIG. 1, a thermal calendar device CA designed in accordance with the above-mentioned conditions is disposed downstream of the drying device 7, so that the composite nonwoven fabric of the present invention can be efficiently manufactured. In other words, by subjecting the composite nonwoven fabric WP of the present invention to the calendar treatment under the above-mentioned conditions, the bulkiness is suppressed while maintaining the necessary water absorption performance and wiping ability.

[0041] Note that FIG. 1 shows an example in which a thermal calendaring device CA is preferably added online. It is preferable to provide the thermal calendaring device CA integrally with the nonwoven fabric wiper manufacturing apparatus in this manner, but it is also possible to first wind the nonwoven fabric wiper WP around a roller 81 and then perform thermal calendaring offline using a separately provided thermal calendaring device CA.

[0042] In the manufacturing apparatus of Fig. 1, the laminate is subjected to a heat calendaring process after the drying process, so that the manufactured composite nonwoven fabric is compressed and has a low bulk, but the number of pulp fibers in the pulp fiber web does not change, and the bonds between the fibers do not increase, so that the fibers can return to a bulky state when they come into contact with liquid (the density between the fibers returns to a low state due to water absorption). In this way, the composite nonwoven fabric of the present invention maintains its water absorption performance. As a method for reducing the bulk of a composite nonwoven fabric, it is possible to perform a calendaring process (press roll process) on the wet laminate before the drying process, but in this case, the bonding between the pulp fibers is promoted, so the density between the fibers does not return to a low state when water is absorbed, and the water absorption performance remains reduced. Therefore, it is understandable that it is preferable to perform a heat calendaring process after the drying process. In addition, the reason why the calender roll is preferably a plain roll as described above is that if the composite nonwoven fabric is sandwiched between rolls having an uneven surface, there will be some parts that are not pressed, and the bulkiness cannot be sufficiently suppressed. In addition, if heating is not performed, the thermal energy required for pressing is low, and the effect of reliably suppressing the bulkiness cannot be obtained.

[0043] (Example) Hereinafter, a composite nonwoven fabric according to an embodiment of the present invention will be described, which was produced by the above-mentioned production apparatus and then the drying step followed by a thermal calendaring process. Basis weight, thickness, density, water absorption per area (g / m 2 ) and water absorption per density (g / cm 3 The composite nonwoven fabrics of Examples 1 to 16 and Comparative Examples 1 to 7 (Table 3) were manufactured to have the water drop absorbency and wet Taber values ​​shown in Tables 1 and 2. The composite nonwoven fabrics were evaluated for ease of wiping, compactness, shape stability, strength (ease of tearing), and stiffness according to the following criteria.

[0044] The evaluation criteria are as follows: 1) Water absorption performance The water absorption performance was confirmed using two types of TWA values. TWA(g / m2 ): Water absorption per unit area of ​​the composite nonwoven fabric. TWA(g / cm 3 ): The water absorption per unit volume of the composite nonwoven fabric. A high value indicates that the fabric has a high water absorption capacity despite its low thickness. 2) Ease of wiping The ease of wiping off dirt or other stains using the composite nonwoven fabric was evaluated on a 5-point scale. In the evaluation, those that had no problems with flexibility or water absorption were given a "3," those that were slightly better than a "3" were given a "4," and those that were clearly better than a "3" were given a "5." Conversely, those that were slightly worse than a "3" were given a "2," and those that were clearly worse than a "3" were given a "1." 3) Compactness The fact that the bulkiness of a commercialized composite nonwoven fabric is suppressed means that the composite nonwoven fabric has excellent compactness, so the compactness of the nonwoven fabric was evaluated. Here, the higher the product weight per unit volume, the higher the compactness (the greater the effect of suppressing bulkiness), and the evaluation was made on a 5-point scale. 3 More than 0.27g / cm 3 Those with a density of less than 0.27 g / cm are rated "3". 3 More than 0.30g / cm 3 Those with a density of less than 0.30 g / cm are rated as "4". 3 The above was rated as "5". On the other hand, the density was 0.23g / cm 3 More than 0.25g / cm 3 Those with a density of less than 0.23 g / cm are classified as "2". 3 Anything less than that was rated as "1." 4) Shape stability The composite nonwoven fabric was rubbed by hand and the separation of the pulp fiber web and the spunbond nonwoven fabric was visually evaluated on a 5-point scale. The evaluation was carried out as follows: "3" indicates that there was no problem with the separation of the pulp fiber web and the spunbond nonwoven fabric after use, "4" indicates that it was slightly better than "3," and "5" indicates that it was clearly better than "3." Conversely, "2" indicates that it was slightly worse than "3," and "1" indicates that it was clearly worse than 3. 5) Strength (ease of breaking) The ease of tearing when the composite nonwoven fabric was pulled by hand was evaluated on a 5-point scale. A "3" was given to a material that had no problems with strength (ease of tearing) when used, a "4" was given to a material that was slightly better than a "3," and a "5" was given to a material that was clearly better than a "3." Conversely, a "2" was given to a material that was slightly worse than a "3," and a "1" was given to a material that was clearly worse than a "3." 6) Roughness The feel of the composite nonwoven fabric was evaluated on a 5-point scale. A "3" was given if the hardness and stiffness during use was not a problem, a "4" was given if it was slightly better than a "3," and a "5" was given if it was clearly better than a "3." Conversely, a "2" was given if it was slightly worse than a "3," and a "1" was given if it was clearly worse than a "3."

[0045] [Table 1]

[0046] [Table 2]

[0047] [Table 3]

[0048] Examples 1 to 16 shown in Tables 1 and 2 above can be provided as products, but Comparative Examples 1 to 7 shown in Table 3 above did not receive sufficient evaluations in terms of ease of wiping, compactness, shape stability, strength, or stiffness, or had poor water absorption performance, and therefore cannot be provided as nonwoven fabric products.

[0049] The above Examples 1 to 16 have a basis weight of 52.0 to 130.0 g / m 2 , thickness 0.13~0.35mm, density 0.25~0.60g / cm 3 , water absorption per unit area is 280g / m 2 or more, and the water absorption per density is 1.2g / cm 3Within the above preferred ranges, the composite nonwoven fabric maintains the water absorption performance, ease of wiping, and appropriate rigidity required for the composite nonwoven fabric, while suppressing bulkiness, thereby contributing to reducing material costs and logistics costs when the product is manufactured.

[0050] On the other hand, Comparative Examples 1 to 7 are not suitable for products, as described below. In Comparative Example 1, the basis weight was too low, so the water absorbency was low and the ease of wiping was poor. Comparative Example 2 has too high a basis weight, so is hard and is poorly wipeable. In Comparative Example 3, the thickness is too high, so the density is low and the compactness is poor. In Comparative Example 4, the thickness was too small, so the water absorbency was low and the ease of wiping was poor. Comparative Example 5 has poor compactness because the density is too low. Comparative Example 6 has too high a density, so is hard and is poorly wipeable. In Comparative Example 7, the basis weight and thickness were too low, so the water absorbency was low and the ease of wiping was poor.

[0051] The composite nonwoven fabrics in the above-mentioned embodiments are those in which a pulp fiber web is supplied dry using a dry airlaid method. However, the present invention is not limited to this and can be similarly applied to composite nonwoven fabrics that use a pulp fiber web obtained wet, such as a wet papermaking method. However, the dry airlaid method described above can reduce the manufacturing equipment and costs compared to the wet method.

[0052] This concludes the description of the embodiment, but it goes without saying that the present invention is not limited to the above embodiment, and can be implemented with various modifications without departing from the spirit of the present invention. [Explanation of symbols]

[0053] 1. Composite nonwoven fabric manufacturing equipment 2 Air Raid Equipment 3 Spunbond nonwoven fabric supply device 4 Suction device 5 Hydro-entangling device 6 Suction device 7 Drying equipment 8 Winding device 21 Fiberizer 22 Duct 23 Air Raid Hopper 24 Stacking position 28 Clamping roller 30 Pre-wetting device 31 Spray nozzle 32 Suction device 41 Suction device main body 42 Suction section 43 Transport Wire 51 Water Jet Head 52 Suction device 55 Transport Wire SW spunbond nonwoven fabric PF pulp fiber PFW Pulp Fiber Web PWeb Pre-Laminate (Laminate Web) WP composite nonwoven fabric TD Transport direction CA Heat Calendaring Machine

Claims

1. A method for producing a composite nonwoven fabric in which a pulp fiber web is laminated and integrated onto a spunbond nonwoven fabric, comprising the steps of: The method includes at least a hydroentanglement step of promoting integration of the pulp fiber web and the spunbonded nonwoven fabric to obtain a laminate, and a drying step of drying the laminate after the hydroentanglement step, A thermal calendering step is included after the drying step, in which the laminate is passed between calender rolls while being heated and pressed, In the heat calendering step, a main roll and a receiving roll are used, the roll equivalent diameter of which is calculated by the formula (roll equivalent diameter)=(main roll diameter)×(receiving roll diameter) / {(main roll diameter)+(receiving roll diameter)} and is 100 to 400 mm, and the conveying speed is set to 150 to 280 m / min, the gap between the rolls is set to 0 to 0.3 mm, and the roll nip pressure is set to 1.0 to 8.0 MPa. A method for producing a composite nonwoven fabric, characterized in that the temperature of the roll is set to 40 to 200°C.

2. The composite nonwoven fabric has a basis weight of 52.0 to 130.0 g / m ２ , thickness 0.13-0.35 mm, density 0.25-0.60 g / cm ３ The water absorption per unit area is 280 g / m ２ or more, and the water absorption per density is 1.2 g / cm ３ The method for producing a composite nonwoven fabric according to claim 1, characterized in that

3. A method for producing a composite nonwoven fabric as described in claim 2, characterized in that the composite nonwoven fabric has a drop absorbency of 3.0 seconds or less and a wet Taber value of 5 times or more.

4. The composite nonwoven fabric has a basis weight of the pulp fiber web of 40.0 to 100.0 g / m ２ and a weight ratio of the spunbond nonwoven fabric to the pulp fiber web is 40 / 60 to 10 / 90 (wt %).

5. The composite nonwoven fabric has a basis weight of 7.0 to 30.0 g / m ２ The spun resin fibers are connected to each other by a plurality of fusion points, and the area of ​​the fusion points is 0.10 to 0.50 mm ２ The area ratio of the fusion points per unit area is 7 to 20%, and the number of fusion points is 10 to 150 / cm ２ The method for producing a composite nonwoven fabric according to any one of claims 1 to 4,

6. A method for producing a composite nonwoven fabric described in any one of claims 1 to 5, characterized in that the material of the spunbond nonwoven fabric is one type or a mixture of two or more types selected from the group consisting of nylon, vinylon, polyester, acrylic, polyethylene, polypropylene and polystyrene.

7. A method for producing a composite nonwoven fabric as described in any one of claims 1 to 6, characterized in that the pulp fiber web is made of fibers of bleached coniferous kraft pulp selected from the group consisting of radiata pine, slash pine, southern pine, lodgepole pine, spruce and Douglas fir.

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