Composite nonwoven fabric and its manufacturing method

Abstract

To provide a conjugate type nonwoven fabric suppressed in generation of paper powder even when used in any of a dry state or a wet state.SOLUTION: A conjugate type nonwoven fabric is composed of pulp fiber webs laminated onto and integrated with a spun-bonded nonwoven fabric. The conjugate type nonwoven fabric has basis weight of 52.0 to 95.0 g / m2, thickness of 0.20 to 0.42 mm, density of 0.19 to 0.25 g / m3, and a TS7 value of 15.0 dBV2 rms or less on the pulp fiber web side measured by a tissue softness measuring device TSA.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 spunbonded nonwoven fabric has both the liquid absorbency derived from the pulp fibers and the strength derived from the spunbonded nonwoven fabric, and is therefore 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] As described above, when a pulp fiber web is supplied onto a spunbonded nonwoven fabric in a dry or wet manner and then subjected to a hydroentanglement treatment, the pulp fibers on the spunbonded nonwoven fabric are oriented in various directions (three-dimensional random) due to the influence of the water flow. Then, the fabric is dried to become a composite nonwoven fabric as a product. In such composite nonwoven fabrics, it is often found that some of the pulp fibers aligned in the thickness direction are protruding. The fibers aligned in the thickness direction are then dried as they are to be formed into a bulky fabric. Such a bulky nonwoven fabric is used in either a dry or wet state, and it has been confirmed that the protruding fibers are partially worn away and fall off as fine paper powder (fine pulp fibers). Such a nonwoven fabric has poor value as a product. However, up to now, no technology has been established that can effectively suppress the generation of paper dust.

[0006] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a composite nonwoven fabric which can suppress the generation of paper dust whether it is used in a dry or wet state. [Means for solving the problem]

[0007] 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 95.0 g / m 2 , thickness is 0.20~0.42mm and density is 0.19~0.25g / cm 3 and the TS7 value measured by the tissue softness measuring device TSA on the pulp fiber web side is 15.0 dBV. 2 This can be achieved by the composite nonwoven fabric, which is characterized by having a density of rms or less.

[0008] The drop absorbency is 0.5 to 3.0 seconds, and the water absorption (TWA) is 250 to 450 g / m 2 It is preferable that: Also, the wet Taber value is preferably 5 or more.

[0009] The pulp fiber web has a basis weight of 40.0 to 83.0 g / m 2 Moreover, 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 20.0 g / m 2 The spunbond nonwoven fabric is formed to include a plurality of fusion points that bond the spun resin fibers, and the area of ​​each fusion point 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 the fusion points is 10 to 150 / cm 2 It is preferable that:

[0011] The spunbond nonwoven fabric may be 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. is preferred.

[0012] The pulp fiber web is preferably comprised 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 in which a pulp fiber web is laminated and integrated onto a spunbond nonwoven fabric, the method comprising 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 comprising a wet press step of pressing the laminate in a wet state after the hydroentanglement step and before the drying step with a press roll.

[0014] In the wet pressing step, it is preferable to use an upper press roll and a lower press roll having a roll equivalent diameter of 75 to 300 mm, calculated by the formula (roll equivalent diameter) = (upper press roll diameter) x (lower press roll diameter) / {(upper press roll diameter) + (lower press roll diameter)}, and to set the conveying speed to 100 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. Effect of the Invention

[0015] The composite nonwoven fabric according to the present invention, in which the basis weight, thickness, density, and TS7 value measured by a tissue softness analyzer TSA on the pulp fiber web side are set within a predetermined range, can be provided as a nonwoven fabric product in which the generation of paper dust is suppressed. Furthermore, the manufacturing method of the present invention can efficiently manufacture the composite nonwoven fabric. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram showing an apparatus for carrying out a method for producing 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) and density (g / cm 3 ), and the TS7 value (dBV) measured by the tissue softness measuring device TSA on the pulp fiber web side. 2 The inventors have confirmed that a composite nonwoven fabric in which the rms value is within a predetermined range can suppress the generation of paper powder, and have arrived at the present invention. Such a composite nonwoven fabric can be produced by subjecting the laminate in a wet state after the hydroentanglement step to a wet press treatment using a press roll.

[0018] The basis weight of the composite nonwoven fabric according to the present invention is 52.0 to 95.0 g / m 2 , preferably 60.0 to 85.0 g / m 2 The thickness is set to 0.20 to 0.42 mm, preferably 0.28 to 0.40 mm, and the density is set to 0.19 to 0.25 g / c m 3 , preferably 0.21 to 0.25 g / cm 3 The TS7 value of the pulp fiber web side measured by the tissue softness measuring device TSA is set to 15.0 dBV. 2 rms or less, preferably 12.0 dBV 2 It is set below rms.

[0019] The TS7 value was measured using a tissue softness analyzer (TSA). When a composite nonwoven fabric (sample) is placed on a sample stage with the pulp side facing up and rotated by pressing a rotor with blades against it, the vibration data detected by various sensors is analyzed and parameterized (TS value), and the softness of nonwoven fabrics is usually quantitatively evaluated. This is the product name of Emtec Electronic GmbH of Germany (Japan distributor is Nippon Luft Co., Ltd.). In measurements using the above-mentioned tissue softness measuring device TSA, for example, the vibration of the sample stage is measured by a vibration sensor installed inside the sample stage, and the vibration frequency is analyzed and parameterized (TS value). The vibration frequency depends on the structural dimensions of creep processing, embossing processing, etc., and the rotation speed of the blade. The induction of horizontal vibration of the blade itself (resonant frequency: for example, 6500 Hz) occurs when the blade advances over the surface of the sample, due to momentary interruption by a convex part of the sample and the vibration of the blade. The intensity of the maximum peak in the spectrum including the resonant frequency of 6500 Hz (around 6500 Hz) is expressed as the TS7 value (dBV 2 rms).

[0020] The software for analyzing vibration and parameterizing (TS value) can be the emtec measurement system. This software is equipped with various algorithms (e.g., Base Tissue, Facial, TP, etc.), and the TS7 value is automatically obtained on the software, and the HF (hand feel) value is calculated from this TS7 value or the basis weight, thickness, number of plies, etc., depending on the type of algorithm. In the present invention, the TS7 value is specified instead of the HF value, and any algorithm can be used as long as the measurement conditions are met, and the TS7 value does not change depending on the type of algorithm. In the present invention, the TS7 value, which was previously an index of softness, is used to evaluate the state of fibers protruding from the surface of a pulp fiber web. The purpose of this will be described later.

[0021] As shown above, the basis weight (g / m 2 ), thickness (mm), density (g / cm 3 ) and the TS7 value (dBV 2 The composite nonwoven fabric of the present invention, which is designed so that the tensile strength (rms) is within a predetermined preferred range, generates less paper dust and has good water absorbency. The thickness of the composite nonwoven fabric is, for example, 37.85 g / cm, as measured by a Peacock paper thickness gauge. 2 It can be measured under load. Furthermore, the drop water absorbency, which is an index of water absorption performance, is 0.5 to 3.0 seconds, and the water absorption amount (TWA: Total Water Absorbency) is 250 to 450 g / m 2The drop water absorbency is preferably set to 100%. The drop water absorbency is based on the water absorption rate test specified in JIS L 1907 and can be obtained by measuring the time (seconds) from when a 0.1 ml water drop reaches the surface of the test piece until the mirror reflection of the test piece disappears. The TWA can be obtained as follows. First, the nonwoven fabric is cut into a 75 x 75 mm square to prepare a test piece, and the dry weight is measured. Next, the test piece is immersed in distilled water for 2 minutes, and then the test piece is hung in a container saturated with water vapor so that one corner of the test piece becomes the top, and this top and two adjacent corners are supported and hung in a stretched state (100% RH), and the test piece is left for 30 minutes and the weight after draining is measured. A paper towel cut to 3 x 38 mm is used for draining. The measured value is then measured for 1 m of the test piece. 2 Water retention per unit (g / m 2 ) can be obtained by converting Furthermore, it is preferable that the abrasive is designed so that the wet Taber value, which is an index of durability, is 5 times or more. Using a Taber tester specified by JIS, a sample moistened with water is attached to a rotating horizontal disk, and a pair of friction wheels formed of abrasive grain combination is applied under a specified load, and it is preferable that the abrasion resistance is such that the wet Taber value is at least 5 times.

[0022] The basis weight of the pulp fiber web is 40.0 to 83.0 g / m 2 The weight ratio of the spunbond nonwoven fabric to the pulp fiber web is preferably 40 / 60 to 10 / 90 (wt%). A composite nonwoven fabric in this range has excellent water absorption performance and excellent shape stability. The basis weight of the spunbond nonwoven fabric is 7.0 to 20.0 g / m 2 In 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 fusion points per unit area is 7-20%, and the number of fusion points is 10-150 / cm 2Such 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.

[0023] 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.

[0024] The steps 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 subjecting the laminate in a wet state after the hydroentanglement step to a predetermined wet press treatment using a press roll, thereby suppressing the generation of paper powder. Here, the main configuration of the production device for producing the composite nonwoven fabric WP will first be described, and then the wet press step according to the present invention will be described.

[0025] 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.

[0026] The airlaid apparatus 2 includes a defibrator 21 that defibrates raw pulp RP, which is a sheet-like material in which fibers are densely packed together, 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.

[0027] 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.

[0028] 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).

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 1, a suction device 6 and a dryer 7 are provided downstream of the hydroentanglement device 5 to suck and remove the water remaining in the web, and then dry the web to complete the production of the composite nonwoven fabric WP. By performing dehydration and drying using the suction device 6 and the dryer 7 in this manner in the latter stages of the production of the composite nonwoven fabric WP, the nonwoven fabric can be produced efficiently, and a dried nonwoven fabric can be produced without applying a large external pressure to the hydroentangled nonwoven fabric produced. The suction device 6 is, for example, 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, and it is preferable that hot air heated by a heat source (not shown) is sucked from the outer periphery of the dryer body toward the center. The composite nonwoven fabric WP thus continuously produced is wound around the roller 81 of the winding device 8, completing a series of steps.

[0037] Although a general composite nonwoven fabric can be manufactured by the above steps, the composite nonwoven fabric of the present invention is a nonwoven fabric in which generation of paper powder is suppressed.To achieve this, a step is provided in which the wet laminate after the hydroentangling step using the hydroentangling device is subjected to a wet press treatment using a roll.

[0038] The wet press device 9 for performing the wet press step is disposed immediately after the hydroentangling device 5 and before the suction device 6, and is equipped with an upper press roll 9a on the upper side in contact with the pulp fiber web PFW side and a lower press roll 9b on the lower side. The pulp fiber web PFW contacts the upper press roll 9a, and the spunbond nonwoven fabric SW layer contacts the lower press roll 9b. The upper press roll and the lower press roll are desirably designed so that the roll equivalent diameter calculated by the formula (roll equivalent diameter) = (upper press roll diameter) x (lower press roll diameter) / {(upper press roll diameter) + (lower press roll diameter)} is 75 to 300 mm, more preferably 100 to 250 mm. The roll equivalent diameter here is based on the literature presented by AV Lyons et al. (1990 TAPPI Finishing and Converting, p. 5). The roll equivalent diameter can be used as an index of the smoothing effect of the fibers protruding from the pulp fiber web PFW (hereinafter simply referred to as the pulp fiber web) in the composite nonwoven fabric WP. For example, if the roll equivalent diameter is less than 75 mm, the force applied to the surface is too small, so the effect of smoothing the protruding pulp fibers is small, and the paper dust suppression effect is small. It should be noted here that the evaluation of the pulp fibers protruding from the surface of the pulp fiber web side of the composite nonwoven fabric can be performed using the TS7 value (measured on the pulp surface side) of the TSA measurement described above. As described above, the TS7 value is originally an index of the softness of tissue paper, but if there are many protruding fibers, there will be many fibers that come into contact with the blade (measurement feather) in the TSA measurement, and the TS7 value will be large. In this way, a composite nonwoven fabric with a large TS7 value has many protruding fibers, so when used as a wiper, it will generate a lot of paper dust. In the present invention, the TS7 value is used to confirm a composite nonwoven fabric in which paper dust generation is suppressed. As mentioned above, the TS7 value is preferably 8.0 to 15.0 dBV2rms. If the roll equivalent diameter is greater than 300 mm, the surface of the composite nonwoven fabric on the pulp fiber web side will become hardened.

[0039] Furthermore, the roll nip pressure between the upper press roll 9a and the lower press roll 9b is preferably set to 1.0 to 8.0 MPa, the gap between the rolls is preferably set to 0 to 0.3 mm, and the roll conveying speed is preferably set to 100 to 280 m / min, more preferably 150 to 250 m / min. By setting the operating conditions of the wet press device 9 within the above ranges, the fibers protruding from the pulp surface of the composite nonwoven fabric are smoothed, and the generation of paper dust during use of the composite nonwoven fabric can be reliably suppressed. Furthermore, if the conveying speed is too fast, the gap between the rolls is too wide, or the roll nip pressure is too low compared to the above-mentioned ranges, the effect of suppressing fiber protrusion of the pulp fiber web of the composite nonwoven fabric will be weakened, and as a result, the effect of suppressing paper dust will be reduced (more paper dust will be produced during use). Conversely, if the conveying speed is too slow or the roll nip pressure is too high, too much force acts on the composite nonwoven fabric, causing the surface of the pulp fiber web of the composite nonwoven fabric to harden, resulting in a decrease in thickness and an increase in density. Such a composite nonwoven fabric has a slow water absorption rate, a low TWA value, and a hard feel like paper. This composite nonwoven fabric also results in poor usability as a wiper. Although there is no particular limitation on the material of the upper press roll 9a and the lower press roll 9b, it is preferable to use metal rolls for both.

[0040] In the composite nonwoven fabric manufacturing apparatus shown in Fig. 1, an example is shown in which the wet press unit 9 is disposed before the suction unit (dewatering unit) 6, but it may be disposed between the suction unit 6 and the drying unit 7. In this case, the suction unit 6 may be designed to suck only enough to remove the remaining moisture around the laminate WP, so that the pulp fiber web PFW is maintained in a wet state. In the composite nonwoven fabric WP according to the present invention, the fibers protruding from the surface are leveled by performing a wet press process after hydroentanglement. As described above, in the pulp fiber web PFW in a wet state, the bonds (hydrogen bonds) between the pulp fibers are not firmly established and the bonds are loose. In this state, the protruding fibers are leveled by the wet press device 9, and then the leveled state is maintained by quickly performing a drying process, and a smooth and high-density pulp fiber web PFW can be formed. This makes it possible to obtain a composite nonwoven fabric that suppresses the generation of paper dust. The state of the surface of the pulp fiber web PFW side where the protruding fibers have been leveled in this way can be confirmed by the TS7 value. It was also considered that a press roll treatment after the drying process could be used to increase the bonds between the pulp fibers, but although this would increase the density of the surface, the dry state would not promote hydrogen bonding, and the paper dust generated during use would not be improved.

[0041] (Example) The composite nonwoven fabrics of the examples produced by the above-mentioned production apparatus will be described below. The composite nonwoven fabrics of Examples 1 to 5 and Comparative Examples 1 to 6, which were manufactured to have the basis weight, thickness, density and TS7 values ​​shown in Table 1, were subjected to sensory evaluations of the amount of fallen fibers when the composite nonwoven fabric was used (in a dry state and in a wet state) and the ease of wiping, according to the following criteria. Since the evaluation of the ease of wiping is particularly important for nonwoven fabrics used as wipers, it was decided to evaluate it together with the amount of fallen paper powder. Even if the amount of fallen fibers was small, those that were poor in ease of wiping were considered undesirable composite nonwoven fabrics and were used as Comparative Examples. 1) The ease of wiping off dirt and other stains from a target object using the composite nonwoven fabric was evaluated. Ease of wiping evaluation: Both flexibility and stiffness are moderately soft and easy to wipe (Excellent ◎), No problem with ease of wiping (Good 〇), Too soft and stiff and difficult to wipe (Poor ×) 1 ), too hard and inflexible, difficult to wipe (not good x 2 ), and 2) A black smooth plastic plate was rubbed against the pulp side of the composite nonwoven fabric, and the amount of paper powder that fell off was visually evaluated. Load: 3.5 kg, number of wipes: 250 mm x 20 times. * Dry state: The composite nonwoven fabric was rubbed against the board in a dry state without any liquid being applied to it. * Wet state: The composite nonwoven fabric was soaked in liquid (water) (impregnation rate: about 200%) and rubbed against a board in a wet state. Moisture content = amount of water (g) / nonwoven fabric (g). Evaluation of fallen paper dust: Almost no fallen paper dust was seen (Excellent ◎), some fallen paper dust was seen but still usable without any problems (Good ◯), too much fallen paper dust made it difficult to use (Unacceptable ×).

[0042] [Table 1]

[0043] [Table 2]

[0044] As shown in Table 1 above, Examples 1 to 5 were able to be provided as products, but as shown in Table 2 above, Comparative Examples 1 to 6 were unacceptable in terms of either ease of wiping or fallen paper powder.

[0045] The above Examples 1 to 5 have a basis weight of 52.0 to 95.0 g / m 2 , thickness 0.20~0.42mm, density 0.19~0.25g / cm 3 , and the TS7 value is 15.0 dBV 2 It is within the preferred range of less than rms.

[0046] On the other hand, Comparative Example 1 is too thin and too dense, and although the TS7 value is small and the amount of paper powder falling off is suppressed, it is evaluated as being too hard and inflexible, making it difficult to wipe off. It can also be confirmed that the water absorbency is low. Moreover, Comparative Example 2 was evaluated as being too thick, having too low a density, and having too high a TS7 value, resulting in a lot of paper dust and being too soft and lacking stiffness, making it difficult to wipe off. In addition, Comparative Example 3 was too thick and had an excessively large TS7 value, and was rated as excellent in terms of ease of wiping, but produced a large amount of paper dust. In addition, Comparative Example 4 had too high a density, and although the TS7 value was within the suitable range and the falling off of paper powder was suppressed, it was evaluated as being too hard and lacking in flexibility, making it difficult to wipe off. In addition, in Comparative Example 5, the basis weight was too low, the thickness was too thin, and the TS7 value was small, suppressing the amount of paper dust that fell off, but it was evaluated as being too soft and lacking in stiffness, making it difficult to wipe off. In addition, in Comparative Example 6, the basis weight was too large and the thickness was too thick. Although the TS7 value was within the suitable range and the amount of paper powder falling off was suppressed, the paper was evaluated as being too hard and inflexible, and difficult to wipe off.

[0047] 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]

[0048] 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 (dehydration) device 7 Drying equipment 8 Winding device 9. Wet press equipment 9a Upper press roll 9b Lower press roll 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

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, The method further includes a wet pressing step of pressing the laminate in a wet state after the hydroentanglement step and before the drying step with a press roll, The wet pressing step uses an upper press roll and a lower press roll having a roll equivalent diameter of 75 to 300 mm, calculated by the formula (roll equivalent diameter) = (upper press roll diameter) x (lower press roll diameter) / {(upper press roll diameter) + (lower press roll diameter)}, and sets the conveying speed to 100 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.

2. The composite nonwoven fabric produced has a basis weight of 52.0 to 95.0 g / m ２ , the thickness is 0.20 to 0.42 mm, the density is 0.19 to 0.25 g / cm 3, and the TS7 value of the pulp fiber web side measured by a tissue softness measuring device TSA is 15.0 dBV. ２ 2. The method for producing a composite nonwoven fabric according to claim 1, wherein the rms is less than or equal to 1.

3. The method for producing a composite nonwoven fabric according to claim 1 or 2, characterized in that the produced composite nonwoven fabric has a drop absorbency of 0.5 to 3.0 seconds and a water absorption amount (T.W.A.) of 250 to 450 g / m 2 .

4. A method for producing a composite nonwoven fabric described in any one of claims 1 to 3, characterized in that the composite nonwoven fabric produced has a wet Taber value of 5 or more.

5. A method for producing a composite nonwoven fabric as described in any one of claims 1 to 4, characterized in that the composite nonwoven fabric produced has a basis weight of the pulp fiber web of 40.0 to 83.0 g / m2, and a weight composition ratio of the spunbond nonwoven fabric to the pulp fiber web of 40 / 60 to 10 / 90 (wt %).

6. A method for producing a composite nonwoven fabric as described in any one of claims 1 to 5, characterized in that the composite nonwoven fabric produced has a basis weight of the spunbond nonwoven fabric of 7.0 to 20.0 g / m2 and is formed to include a plurality of fusion points that join the spun resin fibers of the spunbond nonwoven fabric, the area of ​​each fusion point being 0.10 to 0.50 mm2, the area ratio of the fusion points per unit area being 7 to 20%, and the number of fusion points being 10 to 150 / cm2.

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

8. A method for producing a composite nonwoven fabric as described in any one of claims 1 to 7, characterized in that the composite nonwoven fabric produced is 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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