Composite nonwoven fabric roll

Abstract

To provide a conjugate type nonwoven fabric roll body that is excellent in embossment shape retention despite thinness thereof and excellent in wiping property both in dry and wet states, workability and water absorption.SOLUTION: A conjugate type nonwoven fabric roll body contains pulp fibers and synthetic fibers and is obtained by spun lace processing, subjected to emboss processing for one ply, and wound so that wound length / roll volume is 0.0050 m / cm3 or more and 0.0085 m / cm3 or less. Basis weight of the conjugate type nonwoven fabric is 30 g / m2 or more and 69.0 g / m2 or less. Basis weight of the synthetic fiber is 8 g / m2 or more and 13 g / m2 or less. Depth of emboss formed by the emboss processing is 0.1 mm or more and 1.0 mm or less. Tensile strength (DMDT) in transportation direction during manufacture in dry state is 9.8 N / 25 mm or more.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a roll of composite nonwoven fabric made of pulp fibers and synthetic fibers. [Background technology]

[0002] In recent years, rolls of nonwoven fabric wipes, such as hand towel rolls and kitchen towel rolls, have become commercially available, manufactured from paper or nonwoven fabric. Among these, composite nonwoven fabric wipes, made by intertwining synthetic fibers with pulp fibers using water flow, are particularly well-suited for repeated use in wiping tasks. These composite nonwoven fabric wipes are known to come in thick and thin varieties. While thicker wipes offer superior absorbency, their workability is inferior for tasks like wiping up light spills by folding them, rather than handling large amounts of liquid. Therefore, thinner wipes tend to be preferred. Furthermore, making the wipes thinner reduces the overall product weight for the same number of wipes, making them easier to carry and fold for use.

[0003] For example, Patent Document 1 discloses a thin nonwoven wiper (sheet) obtained by setting the average fiber length of pulp fibers, the basis weight of the composite nonwoven fabric, and the composition ratio of pulp fibers to synthetic fibers within a predetermined range. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2018-193634 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Embossing is known to be effective in improving the wiping properties of nonwoven fabrics. However, with the thin nonwoven fabrics mentioned above, the embossing's shape retention is easily impaired, and it is also difficult to maintain the embossing's shape when wet. Therefore, it was found that improvement in wiping properties in both dry and wet conditions could not be expected. In addition, thin nonwoven fabrics tend to have low water absorption because they contain less pulp fiber, and this point also needs to be improved. Furthermore, in recent years, there has been a demand for a roll of composite nonwoven fabric that maintains a relatively compact outer diameter while offering excellent shape retention of the embossing during use, as well as superior wipeability and workability. Here, the nonwoven fabric that becomes the product needs to be wound with a certain amount of tension in order to maintain the shape of the roll when wound up. Also, in the manufacturing process using a roll winder, the raw material comes into contact with multiple rolls when unwound and wound onto a paper tube, and tension is applied. Therefore, the conditions for maintaining the shape retention of the embossing are stricter for roll products compared to flat sheet products.

[0006] Therefore, the object of the present invention is to provide a roll of composite nonwoven fabric that is thin but has excellent embossing shape retention, and excellent wipeability, workability, and water absorption in both dry and wet conditions. [Means for solving the problem]

[0007] The above objective is to provide a roll of composite nonwoven fabric containing pulp fibers and synthetic fibers, obtained by spunlace treatment, It is a single-ply embossed material with a roll length / volume of 0.0050 m / cm². 3 More than ~0.0085m / cm 3 The fabric is wound up as follows, and the basis weight of the composite nonwoven fabric is 30 g / m². 2 More than 69.0g / m 2 The following applies, and the basis weight of the synthetic fiber is 8 g / m². 2 More than 13g / m 2It is as follows, and can be achieved by a roll of composite non-woven fabric, wherein the depth of the emboss formed by the embossing process is 0.1 mm or more and 1.0 mm or less, and the tensile strength (DMDT) in the conveyance direction during manufacturing when dry is 9.8 N / 25 mm or more. And it is preferable that the emboss depth after water wetting of the composite non-woven fabric is 0.5 mm or more.

[0008] The water absorption amount (T.W.A.) of the composite non-woven fabric is 200 g / m 2 or more and 400 g / m 2 or less, and preferably the water absorption speed is 1.5 seconds or less.

[0009] It is preferable that the emboss shape retention property when wet (emboss depth when wet / emboss depth in the dry state × 100) is 80.0% or more.

[0010] And it is preferable that the pulp fibers contain a wet strength agent and an anionic water-soluble polymer. Here, with respect to the absolute dry weight of the pulp fibers, the addition amount of the wet strength agent is preferably 0.35 to 2.00% by weight, and the addition amount of the anionic water-soluble polymer is preferably 0.1 to 1.0% by weight. Also, it is preferable that the anionic water-soluble polymer is carboxymethyl cellulose (CMC).

Advantages of the Invention

[0011] According to the present invention, it is possible to provide a roll of composite non-woven fabric that is thin but has excellent emboss shape retention property, and excellent wiping property, workability, and water absorption property both when dry and when wet.

Brief Description of the Drawings

[0012] [Figure 1] It is a diagram showing the height profile on the X-Y plane by a microscope in shades. [Figure 2] It is a diagram showing the height profile on the X-Y plane by a microscope in a graph. [Figure 3] This is a diagram showing how to determine the depth of the embossment. [Figure 4] This is a diagram showing an apparatus suitable for manufacturing the non-woven fabric according to the present invention.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, a roll body of a composite non-woven fabric according to the present invention will be described. The inventors of the present invention have carefully examined the state of synthetic fibers and pulp fibers on the wall surface of the embossed portion (concave or convex portion) when an embossing treatment is applied to a thin composite non-woven fabric. The synthetic fibers and pulp fibers located on the wall surface portion of the embossed portion are pressed. And it was recognized that in the thin composite non-woven fabric, particularly the amount of pulp fibers in the wall surface portion is reduced, and the tendency for the strength to hold the wall surface to decrease is remarkable. Due to this, as pointed out in the above-described problems, it was understood that even if an embossing treatment is applied to a thin composite non-woven fabric, an improvement in wiping property cannot be expected. Therefore, through detailed technical studies, for a composite non-woven fabric embossed in one ply, the basis weight of the composite non-woven fabric and the synthetic fibers contained therein is set within a predetermined range, the embossment depth is set within a predetermined range, and also the tensile strength in the MD direction during drying (DMDT) is set within a predetermined range, and further, by designing a roll body such that the value of the roll length / roll volume is within a predetermined range, the present inventors have found that a roll body of a composite non-woven fabric that is thin but has excellent embossment shape retention, and excellent wiping property, workability, and water absorption both during drying and during wetting can be obtained, and thus the present invention has been achieved.

[0014] The basis weight of the composite non-woven fabric is 30 g / m 2 or more and 69.0 g / m 2 or less, preferably 45 g / m 2 or more and 65.0 g / m 2 or less is more preferable. Conventionally, in non-woven fabrics that are generally widely used, the basis weight is often around 100 g / m 2 or so, so it can be understood that the composite non-woven fabric of the present invention is a considerably thin non-woven fabric. Here, the basis weight of the synthetic fibers constituting the composite nonwoven fabric is 8 g / m². 2 More than 13g / m 2 The following is preferable: The basis weight of the synthetic fiber is 8 g / m². 2 If the basis weight is less than 13 g / m², the embossing process will deform due to heat, resulting in insufficient structural integrity to maintain shape and poor embossing shape retention. 2 This is because exceeding this limit results in an excessively high embossing height, which shortens the winding length (reducing winding density), causing a problem. The thickness of one ply of the composite nonwoven fabric (mm) was measured at 37.85 g / cm² using a Peacock thickness gauge. 2 It can be measured under load.

[0015] Furthermore, it is preferable that the composite nonwoven fabric is embossed in a single ply, and the depth of the embossing is 0.1 mm or more and 1.0 mm or less. The preferred depth range for this embossing is that if it is less than 0.1 mm, the embossing becomes too small, making it difficult to remove fine dirt particles with the embossed areas (recesses). If it is 1.0 mm or more, the roll must be wound more loosely to ensure sufficient embossing depth, resulting in a shorter roll length. The depth of the embossing can be measured using a microscope. The KEYENCE VR-3100 One-Shot 3D Measurement Microscope can be used. The VR-H1A software can be used for observing, measuring, and analyzing the microscope images. Measurement conditions can be set, for example, to 12x magnification and a field of view of 24mm x 18mm. The magnification and field of view can be adjusted as needed depending on the desired size of the embossing. Figure 1 shows the height profile on the XY plane as measured by a microscope, with the height of the sheet surface indicated by shades of gray. The roughly elliptical areas in Figure 1, where the shades differ from the surrounding areas, represent individual embossing. The depth of the embossing can be determined by measuring the height difference of the embossing using the microscope described above. First, draw line segment AB as shown in Figure 1 to obtain the height profile shown in Figure 2. Note that line segment AB should be drawn so as to cross the embossing. The height profile is the (measured) cross-sectional curve S that represents the surface irregularities of the actual sheet sample, but it also contains noise (steep peaks caused by fiber clumps on the sheet surface, fibers extending in a whisker-like manner, or areas without fibers), and it is necessary to remove such noise peaks when calculating the height difference of the irregularities. Therefore, as shown in Figure 3, the "contour curve" W is calculated from the cross-sectional curve S of the height profile. The difference between the average value of the bottoms P1 and P2 of this contour curve W and the top portion sandwiched between the bottoms P1 and P2 is determined and defined as the emboss depth D1. Similarly, the difference between the average value of the bottoms P2 and P3 and the top portion sandwiched between the bottoms P2 and P3 is determined and defined as the emboss depth D2. D3 is measured in the same manner. Note that D1, D2, and D3 are measured at consecutive locations as shown in Figure 3. This measurement is performed at, for example, 10 locations on the composite nonwoven fabric sheet, and the average value of the data from a total of 30 locations is defined as the emboss depth. If the distance between embossing points (the distance between P1 and P2) is 1 cm or more, instead of measuring at consecutive points, the average value of the bottom points P1 and P2 and the difference between the top point between the bottom points P1 and P2 can be calculated and defined as the embossing depth D1. D1 can then be measured at 30 locations and the average value can be used as the embossing depth. The embossing depth in the dry state was measured using the method described above, while the embossing depth in the wet state was measured after completely immersing the nonwoven fabric sheet in water, squeezing it tightly until no more water droplets fell, and then spreading out the sheet and measuring it in the same way. If the embossing depth in the wet state is 0.5 mm or more, the dirt-removing performance due to the embossing can be maintained at a high level.

[0016] Next, it is preferable that the tensile strength (DMDT: Dry Machine Direction Tensile strength) of the composite nonwoven fabric in the manufacturing transport direction MD (also called the longitudinal direction) during drying is 9.8 N / 25 mm or higher. If this tensile strength (DMDT) is less than 9.8 N / 25 mm, the strength of a single sheet will be insufficient, making it prone to tearing and difficult to use repeatedly. Furthermore, the tensile strength (DCDT: Dry Cross Direction Tensile strength) of the composite nonwoven fabric in the width direction (transverse direction) perpendicular to the transport direction MD can also be measured simultaneously. The longitudinal strength (DMDT) and transverse strength (DCDT) of the composite nonwoven fabric in the dry state can be measured in accordance with JIS P8113.

[0017] Furthermore, the above-mentioned composite nonwoven fabric has a roll length / roll volume of 0.0050 m / cm³. 3 More than ~0.0085m / cm 3 It is preferable to form it as a rolled body wound up as follows. The roll volume can be calculated from [{cross-sectional area of ​​the outer diameter (winding diameter) portion of the roll} - (cross-sectional area of ​​the outer diameter portion of the core)] × roll width. Here, the value of roll length / roll volume is an indicator of compactness. The longer the roll length and the smaller the roll volume, the larger this value is, indicating that the roll is compact. Here, it is preferable for the roll to be formed compactly, but 0.0085 m / cm 3 Those exceeding 0.0085 m / cm² have a high proportion of synthetic fibers, and the deterioration in water absorption becomes noticeable. 3 For example, much larger than 0.0230 m / cm 3 The material has a low basis weight, making it difficult to maintain the embossed shape, and its ability to wipe away dirt deteriorates significantly. Therefore, it is preferable that the roll length / roll volume be within the above range.

[0018] The composite nonwoven fabric roll according to the present invention, which satisfies the above-described configuration, is thin but has excellent emboss shape retention, excellent wipeability, workability and water absorption in both dry and wet conditions, and is a compact composite nonwoven fabric roll. Here, when the composite nonwoven fabric roll of the present invention becomes a product, it is in roll form and is under a certain degree of tension, but the embossed shape is maintained. The composite nonwoven roll of the present invention was obtained by appropriately adjusting the amount of pulp fibers in the composite nonwoven fabric, the added wet paper strength agent, the embossing properties, and the heat embossing treatment conditions, resulting in good shape retention and water absorption of the embossed portion. Other preferred conditions will be further explained below.

[0019] The water absorption capacity (TWA) per unit area of ​​the above composite nonwoven fabric is 200 g / m². 2 More than 400g / m 2 It is preferable that the water absorption rate is within the following range and less than or equal to 1.5 seconds. The above water absorption capacity (TWA) can be determined as follows. First, a sample piece was prepared by cutting the nonwoven fabric into a 75 x 75 mm square, and its dry weight was measured. Next, this sample piece was immersed in distilled water for 2 minutes, and then suspended in a steam-saturated container with one corner of the sample piece as the upper apex, supported by this apex and two adjacent corners, in an extended state (100% RH). After 30 minutes, the weight after draining was measured. Paper towels cut to 3 x 38 mm were used for draining. The measured value was then measured per meter of the sample piece. 2 Water retention capacity per unit (g / m³) 2 It was calculated by converting it to ). Here, 200g / m 2 Nonwoven fabrics with a water absorption rating below a certain level were deemed to have insufficient water absorption. Furthermore, the water absorption rate was measured in accordance with the water absorption rate test specified in JIS L 1907, specifically the time (in seconds) from when a 0.1 ml water droplet reached the surface of the test specimen until the specular reflection of the specimen disappeared.

[0020] Furthermore, it is preferable that the embossing shape retention when wet (embossing depth when wet / embossing depth in dry state × 100) is 80.0% or higher.

[0021] Furthermore, it is preferable that the pulp fibers of the composite nonwoven fabric contain a wet-strength agent and an anionic water-soluble polymer. Here, it is preferable that the amount of the wet paper strength agent added is in the range of 0.35 to 2.00% by weight relative to the oven-dry weight of the pulp fibers, and the amount of the anionic water-soluble polymer added is in the range of 0.1 to 1.0% by weight. Carboxymethylcellulose (CMC) is preferred as the anionic water-soluble polymer.

[0022] As described above, by incorporating a wet-strength agent and an anionic water-soluble polymer on the pulp fiber web side, it is presumed that, in addition to the generally known self-crosslinking of the wet-strength agent to impart water resistance to the cellulose (pulp fibers) and the strengthening of hydrogen bonds between cellulose (pulp fibers) by the anionic water-soluble polymer, the wet-strength agent and the anionic water-soluble polymer also form a crosslinked structure with each other, allowing the wet-strength agent to function effectively, effectively suppressing the shedding of pulp fibers while maintaining water absorption performance. Furthermore, it is presumed that using a wet-strengthening agent in combination with an anionic water-soluble polymer contributes to maintaining the shape retention of embossed cellulose (pulp fibers) when wet.

[0023] In the following, we will first explain the manufacturing process of the composite nonwoven fabric that serves as the base material for forming the roll body of the composite nonwoven fabric according to the present invention described above, and then explain the process of manufacturing the roll body that will become the product from this base material (parent roll). Here, as an example, we will describe a composite nonwoven fabric formed by including a pulp fiber web and a spunbond nonwoven fabric as a synthetic fiber. A suitable manufacturing apparatus for producing composite nonwoven fabrics that will serve as the base material will be described with reference to Figure 4. The general configuration of the composite nonwoven fabric manufacturing apparatus 1 is described below. The manufacturing apparatus 1 shown in Figure 4 has an airlaid device 2 for supplying pulp fiber webs, a spunbond nonwoven fabric supply device 3 for supplying spunbond nonwoven fabric, and a suction device 4 arranged on the upstream side. The suction device 4 is positioned opposite the airlaid device 2, below it. In the conveying direction MD during web manufacturing, downstream of these devices 2, 3, and 4, in order from upstream, are a water flow entanglement device 5 that sprays a water jet for water flow entanglement treatment, a suction device 6 for dewatering treatment, and a drying device 7. Downstream of the drying device 7 is a winding device 8 for winding up the continuously manufactured composite nonwoven fabric (hereinafter also referred to as composite nonwoven fabric WP). Figure 4 shows a preferred example in which a spunbond nonwoven fabric supply device 3 is arranged and a composite nonwoven fabric using spunbond nonwoven fabric is produced. However, this is not the only option; by redesigning the equipment to supply pulp fibers directly onto a conveyor wire without using spunbond nonwoven fabric, it is also possible to obtain a nonwoven fabric consisting only of a pulp fiber web.

[0024] The airlaid apparatus 2 described above includes a defibration machine 21 that defibrates the raw material pulp RP, which is densely packed with fibers and forms a sheet, into pulp fibers, and a duct 22 equipped with a blower (not shown) that transports the defibrated pulp fibers PF to the airlaid hopper 23.

[0025] Furthermore, an airlaid hopper 23 is positioned downstream of the duct 22. Inside this airlaid hopper 23, pulp fibers in a defibrated state descend while dispersing, and are designed to gradually accumulate at a stacking position 24 set on the lower surface, forming a pulp fiber web (PFW). As described above, the airlaid apparatus 2 is a device that can supply pulp fiber webs in a dry manner, and can reduce equipment costs compared to devices that manufacture pulp fiber webs in a wet manner by applying the wet papermaking method. In addition, the airlaid apparatus 2 is a closed system from pulp defibration to dispersion and descent, so the inclusion of foreign matter is prevented, and the inclusion of foreign matter can be kept overwhelmingly low compared to when pulp fiber webs are supplied by the wet papermaking method.

[0026] A suction device 4 is positioned opposite the stacking position 24. More specifically, the suction device 4 has a suction section 42 on the upper surface of the device body 41, and the suction section 42 is set relative to the stacking position 24 to apply suction force (negative pressure) to the pulp fiber web PFW. In Figure 4, an example is shown where the air-laid hopper 23 and the suction device body 41 are arranged in a single stage to form a pulp fiber web (PFW). However, the arrangement is not limited to this, and the air-laid hopper 23 and the suction device body 41 may be changed to a multi-stage arrangement of two or more stages depending on the basis weight (grammage) and manufacturing speed of the pulp fiber web (PFW).

[0027] Furthermore, a conveyor wire 43 for web transport is arranged around the suction device 4. The conveyor wire 43 is positioned to allow the pulp fiber web PFW, which is formed by the accumulation of pulp fibers PF at the stacking position 24, to be placed on it and to transport it downstream. However, the pulp fiber web PFW is not placed directly on the conveyor wire 43. This will become clear in the explanation below. The conveying wire 43 is formed in a mesh shape such that the suction force of the suction section 42 extends to the opposite side (upper side).

[0028] Below the airlaid device 2 described above, upstream of the suction device 4, is a spunbond nonwoven fabric supply device 3. This spunbond nonwoven fabric supply device 3 is set with pre-prepared spunbond nonwoven fabric SW in roll form. That is, as mentioned above, the designed spunbond nonwoven fabric SW is wound into a roll form during manufacturing, and this is drawn out from the spunbond nonwoven fabric supply device 3 and transported to the lamination position 24 on the transport wire 43 described above.

[0029] The pulp fiber web PFW mentioned above is placed on top of the spunbond nonwoven fabric SW located at the lamination position 24. At the lamination position 24, the suction force from the suction section 42 of the suction device 4 passes through the conveyor wire 43 and acts on the spunbond nonwoven fabric SW and pulp fiber web PFW above it. As a result, the preliminary laminate PWeb (laminated web), in which the spunbond nonwoven fabric SW and pulp fiber web PFW are laminated, is conveyed downstream. As described above, when the preliminary laminate PWeb is formed, the amount of pulp fiber web PFW supplied onto the spunbond nonwoven fabric SW can be controlled, so the basis weight of the pulp fiber web PFW contained in the composite nonwoven fabric produced by this apparatus can be controlled to, for example, 23.0 to 55.0 g / m². 2 Therefore, it is desirable to design the fabric so that the proportion of pulp fiber web is higher than that of conventional general composite nonwoven fabrics. The basis weight of the spunbond nonwoven fabric SW should be, for example, 8.0 to 12.0 g / m². 2 The resulting composite nonwoven fabric (spunbond nonwoven fabric SW + pulp fiber web PFW) has a density of, for example, 30.0 to 69.0 g / m². 2 It is preferable to do so. The conveying speed of the pulp fiber web and the amount of pulp fiber web PFW supplied per hour should be appropriately adjusted, and the basis weight of the pulp fiber web PFW of the manufactured composite nonwoven fabric should be checked so that the basis weight falls within the desired range. The conveying speed of the pulp fiber web should preferably be, for example, 150 to 300 m / min.

[0030] The preliminary laminate PWeb described above maintains its laminated state due to suction compression by the suction force of the suction device 4. At this time, the fibers of the upper pulp fiber web PFW are densely packed. However, if the preliminary laminate PWeb is transported and introduced into the downstream water flow entanglement device 5 in this state, there is a risk that some of the pulp fibers PF will be blown up by the water jet (high-pressure water flow). Therefore, the manufacturing apparatus 1 is equipped with clamping rollers 28 to stabilize the placement of the pulp fiber web PFW on the spunbond nonwoven fabric SW by sandwiching the preliminary laminate PWeb from above and below, and a pre-wetting device 30 to apply moisture to prevent fiber scattering upstream of the water flow entanglement device 5. Preferably, the pre-wetting device 30 includes a spray nozzle 31 that sprays water mist from above the preliminary laminate PWeb and a suction device 32 that applies suction force from below the preliminary laminate PWeb (i.e., the lower surface of the pulp fiber web PFW).

[0031] Note that Figure 4 illustrates the case where the pre-wet device 30 is installed as a new device in front of the water flow entanglement device 5, as described above, but it is not limited to this. The design can be modified so that the leading set of the multiple sets of water jet heads 51 and suction devices 52 included in the water flow entanglement device 5 is used as the pre-wet device 30. In this case, adjustments should be made so that a low-pressure water mist is sprayed from the leading water jet head 51. In the case of a water flow entanglement device 5 that has enough sets of water jet heads 51 and suction devices 52 to perform water flow entanglement processing, utilizing 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 water entanglement device 5, a high-pressure water jet is blown onto the preliminary laminate PWeb, which has been processed by the clamping roller 28 and the pre-wetting device 30, to promote entanglement between the pulp fibers. This promotes the integration of the upper pulp fiber web PFW layer and the lower spunbond nonwoven fabric SW layer (water entanglement treatment). The water flow entanglement device 5 shown exemplified in Figure 4 has water jet heads 51 arranged in multiple stages (four stages are shown in the example in Figure 4) along the transport direction MD. Although Figure 4 does not show the nozzles on the water jet head 51 extending in a direction perpendicular to the transport direction MD (the width direction CD of the web), multiple water jet nozzles are arranged at appropriate positions in the width direction. The hole diameter φ of these water jet nozzles is preferably 0.06 to 0.15 mm. Furthermore, the spacing between the water jet nozzles is preferably 0.4 to 1.0 mm.

[0033] The water pressure used in the above-mentioned water flow entanglement treatment should preferably be set considering the basis weight of the pulp fiber web (PFW) and the spunbond nonwoven fabric (SW). For example, it is preferable to select a pressure within the range of 1 to 30 MPa.

[0034] A suction device 52 is positioned opposite the water jet head 51. The high-pressure water jet from the water jet head 51 is blown onto the pulp fiber web PFW located above, while the suction force of the suction device 52 is applied to the underside of the spunbond nonwoven fabric SW located below. 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 penetrate into the spunbond nonwoven fabric SW below, or even penetrate the spunbond nonwoven fabric SW and reach the other side. This action promotes the integration of the two layers.

[0035] A conveyor wire 55 is also installed in the water flow entanglement device 5. The conveyor wire 55 receives the preliminary laminate PWeb downstream of the pre-processing units 28 and 30 and conveys it into the water flow entanglement device 5. The conveyor wire 55 is arranged to pass between the water jet head 51 and the suction device 52 of the water flow entanglement device 5 from upstream to downstream. Therefore, the preliminary laminate PWeb being transported on the transport wire 55 undergoes more water entanglement treatment as it moves downstream in the transport direction MD, and sufficient entanglement treatment is achieved between the upper pulp fiber web PFW layer and the lower spunbond nonwoven fabric SW layer when it leaves the water entanglement device 5. Immediately after exiting the water entanglement device 5, the composite nonwoven fabric is in a wet state, and the bonding between pulp fibers and other components is not yet fully established.

[0036] Therefore, as shown in Figure 4, a suction device 6 and a drying device 7 are provided downstream of the water flow entanglement device 5 to perform a dewatering treatment to suck and remove moisture remaining in the pulp fiber web, followed by a drying treatment to complete the production of the composite nonwoven fabric WP. By performing the dewatering treatment and drying treatment using the suction device 6 and drying device 7 in the later stages of the production of the composite nonwoven fabric WP in this way, the composite nonwoven fabric can be produced efficiently, and a composite nonwoven fabric can be produced that has been dried without applying large external pressure to the composite nonwoven fabric after water flow entanglement. However, as previously noted, it is necessary to create a composite nonwoven fabric that can reliably suppress the detachment of fine pulp fibers (paper dust) from the pulp fiber web on the composite nonwoven fabric WP. For this reason, the manufacturing apparatus 1 is equipped with an additive device 9 for adding an agent to suppress the detachment of pulp fibers.

[0037] The suction device 6, for example, uses a vacuum system to dewater the composite nonwoven fabric from below after water flow entanglement. Above the suction device 6, with the conveyed composite nonwoven fabric WP in between, is an additive device 9 for adding a wet paper strength agent. The additive device 9 adds a mixed additive, which is a mixture of a wet paper strength agent and an anionic water-soluble polymer, to the upper side of the composite nonwoven fabric WP, i.e., the pulp fiber web PWF, after it has been compounded in the water flow entanglement device 5. Since the mixed additive is added from the outside to the surface of the pulp fiber web of the composite nonwoven fabric after compounding is complete, the mixed additive works efficiently to perform the function of connecting the pulp fibers. Since the material is dried downstream of the additive device 9, there is no waste such as the added mixed additive being washed away and flowing out. Furthermore, the presence of a suction device on the lower side is advantageous for the penetration of the mixed additive into the pulp fiber web, thereby more reliably suppressing the shedding of pulp fibers. Adding the additive by spray application is even more advantageous for the sprayed liquid mixed additive to penetrate into the pulp fiber web. In addition, the additive device 9 makes it easy to check the condition of the composite nonwoven fabric WP being manufactured and control the amount of mixed additive. Furthermore, it is preferable to adjust the moisture content of the pulp fiber web (PWF) portion (moisture content at the inlet just before entering the additive device 9) to 120-400% when the mixed additive is spray-applied by the additive device 9.

[0038] Furthermore, it is preferable to dewater the material within 10 seconds after spraying the mixed additive. That is, as explained in Figure 4 above, dewatering may be performed immediately after spraying the mixed additive, or it may be performed at a position slightly away from the spraying (within 10 seconds of the transport time). In short, the optimal time (however, within 10 seconds after spraying) should be determined appropriately by checking the state of penetration and diffusion of the chemical solution into the pulp fiber web (PWF) when the mixed additive is sprayed. The additive device 9 described above can be any known device, such as a spray coating device, a size press, a roll coating device, a gravure coating device, a rod bar coating device, or an air knife coating device, to add the mixed additive. There are no particular limitations, but spray coating is preferred. The additive device 9 described above is explained as a preferred example of applying a mixed additive, which is a pre-mixed mixture of a wetting force agent and an anionic water-soluble polymer, to a pulp fiber web (PWF), but the application method is not limited to this. The wetting force agent and the anionic water-soluble polymer may also be applied individually to the pulp fiber web (PWF). In this case, the additive device 9 is configured to include both a first application device for applying the wetting force agent and a second application device for applying the anionic water-soluble polymer. The first and second application devices may apply their respective agents (wetting force agent and anionic water-soluble polymer) simultaneously, or they may be positioned slightly offset from each other in the web's transport direction. In this case as well, spray application is preferred.

[0039] In the pulp fiber web (PWF) described above, it is preferable that the amount of each of the wet-strength agent and the anionic water-soluble polymer added, calculated based on their solid content, be within a predetermined range relative to the oven-dry weight of the pulp fibers in the pulp fiber web. Specifically, it is preferable that the amount of the wet-strength agent added be 0.35 to 2.00% by weight relative to the oven-dry weight of the pulp fibers in the pulp fiber web. Furthermore, it is preferable that the amount of the anionic water-soluble polymer added be 0.1 to 1.0% by weight relative to the oven-dry weight of the pulp fibers in the pulp fiber web. As mentioned above, the wet strength agent imparts water resistance to the cellulose (pulp fibers) through its own crosslinking. It also contributes to strengthening hydrogen bonds between cellulose fibers (pulp fibers) through the anionic water-soluble polymer. Furthermore, by using both in combination, the wet strength agent and the anionic water-soluble polymer also form a crosslinked structure, contributing to improved shape retention of the embossed area formed by embossing (treating) the pulp fiber web (PWF) side of the composite nonwoven fabric using an embossing device, as well as improved emboss shape retention when wet. Furthermore, as the wet-strength agent, it is preferable to use polyamide epichlorohydrin (PAE), which is known as a wet-strength agent in the papermaking process, as described above. Also, as the anionic water-soluble polymer, it is preferable to use carboxymethylcellulose (CMC), as described above.

[0040] Further downstream of the suction device 6 and additive device 9, a drying device 7 is installed, where the composite nonwoven fabric WP, which includes a pulp fiber web PWF ​​to which the mixed additive has been spray-coated, is dried. The drying device 7 here preferably employs a non-compression type dryer, preferably an air-through dryer. In Figure 4, the rotatable dryer body 71 of the air-through dryer is cylindrical, and numerous through holes are provided on its circumferential surface, and it is preferable that hot air heated by a heat source (not shown) is drawn in from the outer circumference of the dryer body toward the center. As described above, the composite nonwoven fabric WP, which is manufactured continuously, may be wound onto the roll 81 of the winding device 8 after drying. Alternatively, as shown by the dashed line in Figure 4, an embossing device EA may be installed before winding to emboss the pulp fiber web PWF ​​side.

[0041] The detailed configuration of the embossing device EA is omitted, but it comprises an upper main roll, which is an embossing roll that contacts the pulp fiber web (PFW), and a lower plain receiving roll. The outer surface of the embossing roll is engraved with a pattern of raised and recessed areas corresponding to the embossed areas to be formed on the pulp fiber web (PFW). On the other hand, the outer surface of the receiving roll is formed flat. The embossing device EA preferably has a heating means such as an electric heater placed inside the roll, and can set the roll surface temperature to, for example, 80 to 110°C. By heating the surface temperature of the pulp fiber web (PFW) to, for example, 40 to 80°C, the hardening of the synthetic fibers, wet paper strength agent, and anionic water-soluble polymer is promoted, as described above, and the shape retention of the embossed recesses formed can be improved.

[0042] As described above, the manufacturing apparatus 1 in Figure 4 can wind a roll (parent roll) of composite nonwoven fabric that has been embossed in one ply onto the roll 81 of the winding device 8. Subsequently, the raw material is set in a predetermined position in a roll winder device for manufacturing the final roll product, and the composite nonwoven fabric is unfurled while adjusting the tension, thereby winding the composite nonwoven fabric onto a paper tube to a predetermined length and completing the final roll product. Earlier, we explained an example where the embossing device EA is installed on the nonwoven fabric manufacturing device 1 side, but this is not limited to this example. Alternatively, the raw material roll 81 may not be embossed, and the embossing may be performed by installing the embossing device EA on the roll winder device side.

[0043] (Examples) Examples and comparative examples of the composite nonwoven fabric roll body according to the present invention will be described below. For composite nonwoven fabrics embossed in a single ply, the basis weight of the composite nonwoven fabric and the synthetic fibers contained therein, the embossing depth, the tensile strength in the MD direction (DMDT) when dry, and the roll length / roll volume values ​​were as shown in Table 1. For the rolls of composite nonwoven fabrics from Examples 1 to 7, and for Comparative Examples 1 to 8, as shown in Table 2, the water absorption performance, ease of cleaning when wet (wipeability), and bending suitability (workability) were confirmed and a comprehensive evaluation was conducted.

[0044] 1) Water absorption performance We judged whether there was any water residue left after wiping 1 ml of water onto a stainless steel surface with one sheet, according to the following criteria. Can be wiped off completely (Excellent) Water droplets remain (inferior ×)

[0045] 2) The ease with which dirt can be removed when wet was judged according to the following criteria. The embossed surface remains highly defined even when wet, making it easy to remove dirt (Excellent ◎) The embossing is retained when wet and dirt can be scraped off, but it is inferior to the excellent rating (Good ○). The embossing gets crushed when wet, or the original embossing is missing, resulting in poor dirt removal (inferior ×).

[0046] 3) The bending suitability was judged according to the following criteria. It is easy to fold and has good workability when stacked (Excellent) When folded, it becomes thick and difficult to work with (inferior ×)

[0047] 4) The overall evaluation was judged according to the following criteria, with a score of 2 or higher considered a passing grade. Nonwoven fabric rolls that received an excellent rating in all categories (3 points) A roll of nonwoven fabric that is generally of good quality, although it contains one item that received a positive rating (2 points). A roll of nonwoven fabric that receives a poor evaluation in any of the evaluation criteria (1 point)

[0048] [Table 1]

[0049] [Table 2]

[0050] As shown in Table 1 above, in Examples 1 to 7, a composite nonwoven fabric was embossed with one ply, and the basis weight of the composite nonwoven fabric was 30 g / m². 2 More than 69.0g / m 2 The following is the basis weight of the synthetic fibers contained in this nonwoven fabric: 8 g / m² 2 More than 13g / m 2 The following conditions apply: the embossing depth is between 0.1 mm and 1.0 mm, the tensile strength in the MD direction (DMDT) when dry is 9.8 N / 25 mm or more, and the roll length / roll volume value is 0.0050 m / cm². 3 More than ~0.0085m / cm 3The following rolls were produced, and received an overall evaluation of 2 points or higher. These can be provided as nonwoven fabric rolls that are thin but have excellent embossing shape retention, and excellent wipeability, workability, and water absorption in both dry and wet conditions.

[0051] On the other hand, in Comparative Examples 1 to 7, at least one of the following was unsatisfactory: water absorption performance, ease of cleaning when wet (wiping ability), or flexibility (workability), resulting in an overall evaluation of 1. Therefore, these nonwoven fabric rolls were deemed unsuitable for sale as products.

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

[0053] 1. Manufacturing apparatus for composite nonwoven fabrics 2. Air Raid Device 3. Spunbond nonwoven fabric feeding device 4. Suction device 5 Hydro-entangling device 6. Suction device 7 Drying equipment 8 Winding device 9 Addition device 21. Fiber defibring machine 22 ducts 23 Air Raid Hopper 24 Stacking position 28 Clamping roller 30 Pre-wet device 31 Spray nozzle 32 Suction device 41 Suction device body 42 Suction section 43 Conveyor wire 51 Water Jet Head 52 Suction device 55 Conveyor wire SW Spunbond Nonwoven Fabric PF pulp fiber PFW pulp fiber web PWeb Preliminary Laminate (Laminated Web) WP composite nonwoven fabric MD transport direction CD width direction EA Embossing Machine

Claims

1. A roll of composite nonwoven fabric containing pulp fibers and synthetic fibers and obtained by spunlace treatment, It is a single-ply material with an embossed finish, and the roll length / volume is 0.0050 m / cm³. ３ More than 0.0085m / cm ３ It is wound up as follows: The pulp fibers contain a wet paper strength agent and / or an anionic water-soluble polymer. Here, the amount of the wet-strengthening agent added is 0.35 to 2.00% by weight relative to the oven-dry weight of the pulp fibers, and / or the amount of the anionic water-soluble polymer added is 0.1 to 1.0% by weight relative to the oven-dry weight of the pulp fibers. The basis weight of the aforementioned composite nonwoven fabric is 30 g / m². ２ 69.0g / m or more ２ The following conditions apply, and the basis weight of the synthetic fiber is 8 g / m². ２ 13g / m or more ２ A roll of composite nonwoven fabric, characterized in that the depth of the emboss formed by the embossing process is 0.1 mm or more and 1.0 mm or less, and the tensile strength (DMDT) in the conveying direction during manufacturing when dry is 9.8 N / 25 mm or more.

2. The embossing depth of the composite nonwoven fabric after wetting is 0.5 mm or more. Herein, the embossing depth of the composite nonwoven fabric after wetting refers to the value measured after completely immersing the nonwoven fabric in water, squeezing it tightly until no more water droplets fall, and then spreading out the sheet, as described in claim 1 for the roll of composite nonwoven fabric.

3. The water absorption capacity (T.W.A.) of the aforementioned composite nonwoven fabric is 200 g / m². ２ More than 400g / m ２ A roll of composite nonwoven fabric according to claim 1 or 2, characterized in that it is as follows and has a water absorption rate of 1.5 sec or less.

4. The embossed shape retention when wet (embossed depth when wet / embossed depth in dry state × 100) is 80.0% or higher. Herein, the embossing depth when wet refers to the value measured after completely immersing the nonwoven fabric in water, squeezing it tightly until no more water droplets fall, and then spreading out the sheet, as described in any one of claims 1 to 3.

5. A roll of composite nonwoven fabric according to any one of claims 1 to 4, characterized in that the pulp fibers contain a wet paper strength agent and an anionic water-soluble polymer.

6. The roll of composite nonwoven fabric according to claim 5, characterized in that the amount of the wet paper strength agent added is 0.35 to 2.00% by weight relative to the oven-dry weight of the pulp fibers, and the amount of the anionic water-soluble polymer added is 0.1 to 1.0% by weight.

7. The roll of composite nonwoven fabric according to claim 5 or 6, characterized in that the anionic water-soluble polymer is carboxymethylcellulose (CMC).

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