JP2021172936A - Composite nonwoven fabric and manufacturing method thereof - Google Patents

Abstract

To provide a composite nonwoven fabric, which can suppress generation of paper powder even if used in a dry environment and is excellent is use feeling.SOLUTION: A composite nonwoven fabric is formed by stacking a pulp fiber web on a spun-bonded nonwoven fabric so as to be integrated. Basis weight of the composite nonwoven fabric is 52.0 to 88.0 g/m2 and thickness is 0.28 to 0.47 mm. TS7 value indicating the softness of a surface on the pulp fiber web side is 12.0 to 20.0 dBV2 rms. TS750 value indicating the smoothness is 33.0 to 71.0 dBV2 rms.SELECTED DRAWING: Figure 1

Description

The present invention relates to a composite non-woven fabric obtained by water-flow entanglement of a pulp fiber web and a spunbonded non-woven fabric.

The composite non-woven fabric made of pulp fiber web and spunbonded non-woven fabric has both liquid absorption property based on pulp fiber and strength based on spunbonded non-woven fabric. It is widely used in various applications such as wipers for interpersonal use.

For example, as disclosed in Patent Document 1, a pulp fiber web and a spunbonded non-woven fabric are laminated and then integrated by a water flow entanglement treatment in which a high-pressure water jet (water flow) is sprayed. Here, since the spunbonded non-woven fabric has excellent strength, it functions as a backing layer of the manufactured composite non-woven fabric. On the other hand, the pulp fiber web has an excellent liquid absorbing function. Therefore, such a composite type non-woven fabric is an excellent composite type having both advantages of a pulp fiber web having good absorbency in both water-based and oil-based liquids and a spunbonded non-woven fabric having excellent strength. It can be provided to consumers as a non-woven fabric.

Japanese Patent No. 2533260

As described above, when the pulp fiber web is fed dry or wet onto the spunbonded non-woven fabric and then subjected to water flow entanglement treatment, the pulp fibers on the spunbonded non-woven fabric are affected by the water flow in various directions (three-dimensional). Randomly oriented). Then, it is then dried to obtain a composite non-woven fabric as a product. In such a composite non-woven fabric, it is sometimes found that a part of the pulp fibers arranged in the thickness direction is in a protruding state. When such a composite non-woven fabric is used as a wiper in a dry state, the protruding pulp fibers are partially worn to generate fine paper dust. Such a non-woven fabric will be inferior in value as a product.
However, in the past, a technique capable of effectively suppressing the above-mentioned paper dust has not yet been established.

In addition, by applying the conventional technique, it is conceivable to apply a thermal calender treatment to the pulp fiber side to even out the pulp fiber in a partially protruding state, but if the thermal calender is adhered to the composite non-woven fabric to transfer heat, It was confirmed that the thickness of the composite non-woven fabric is reduced to a so-called fluffy state, which is inferior in usability and has major disadvantages such as a decrease in water absorption.

Therefore, an object of the present invention is to provide a composite nonwoven fabric which can suppress the generation of paper dust even when used in a dry environment and is also excellent in usability.

The above object is a composite non-woven fabric in which a pulp fiber web is laminated and integrated on a spunbonded non-woven fabric, and has a basis weight of 52.0 to 88.0 g / m ² and a thickness of 0.28 to 0. It is 47 mm, and the TS7 value indicating the softness of the pulp fiber web side is 12.0 to 20.0 dBV ² rms, and the TS750 value indicating the smoothness is 33.0 to 71.0 dBV ² rms. This can be achieved with the characteristic composite non-woven fabric.

Then, it is preferable that the drip water absorption degree is 0.5 to 3.0 seconds and the water absorption amount (TWA) is 300 to 490 g / m ^2.
Further, it is desirable that the wet taber value is 5 times or more.

Further, the basis weight of the pulp fiber web is 40.0 to 70.0 g / m ² , and the weight composition ratio of the spunbonded nonwoven fabric and the pulp fiber web is 40/60 to 10/90 (wt%). Some are preferred.

Further, the spunbonded nonwoven fabric has a basis weight of 7.0 to 20.0 g / m ² , and the spunbonded nonwoven fabric is formed to include a plurality of fusion points for joining spun resin fibers. It is preferable that the area of one fusion point is 0.10 to 0.50 mm ² , the area ratio of the fusion point per unit area is 7 to 20%, and the number is 10 to 150 pieces / cm ² .

The spunbonded non-woven fabric is preferably formed of one kind selected from the group consisting of nylon, vinylon, polyester, acrylic, polyethylene, polypropylene and polystyrene, or a mixture of two or more kinds.

The pulp fiber web is preferably made of fibers of softwood bleached kraft pulp selected from the group consisting of radiata pine, slash pine, southern pine, lodge pole pine, spruce and douglas fur.

The above object is a method for producing a composite non-woven fabric in which a pulp fiber web is laminated and integrated on a spunbonded nonwoven fabric, and the laminated body is formed by promoting the integration of the pulp fiber web and the spunbonded nonwoven fabric. It further includes at least a water flow entanglement step of obtaining and a drying step of drying the laminate after the water flow entanglement step, and further includes a heat embossing step of applying a heat embossing treatment to the pulp fiber web side after the drying step. The composite non-woven fabric is produced by using an embossed roll having an embossed portion area ratio of 2.0 to 15.0% and an embossed height of 0.2 to 1.0 mm in the embossing step. It can also be achieved by the manufacturing method of.

Then, in the thermal embossing step, the roll equivalent diameter calculated by the formula (roll equivalent diameter) = (embossing roll diameter) × (receiving roll diameter) / {(embossing roll diameter) + (receiving roll diameter)} is 75 to Using an embossed roll and a receiving roll of 300 mm, the transport speed is 150 to 280 m / min, the gap between the rolls is 0 to 0.3 mm, the roll nip pressure is 1.0 to 6.0 MPa, and the embossed roll temperature is 80 to 80 to. It is desirable that the temperature is set to 150 ° C.

The composite nonwoven fabric in which the basis weight, thickness, and softness and smoothness of the pulp fiber web side are set within a predetermined range according to the present invention suppresses the generation of paper dust and is also excellent in usability. Can be provided as a non-woven fabric product. Further, according to the production method of the present invention, the composite non-woven fabric can be efficiently produced.

It is a figure which shows the manufacturing apparatus of a composite type non-woven fabric. It is a figure which shows the schematic structure of the embossing apparatus, and the state of the embossed composite type non-woven fabric schematically. It is a figure shown for demonstrating the form of the embossing roll, FIG. 3A or FIG. It is the top view which showed the part of the surface of a roll enlarged.

Hereinafter, the composite nonwoven fabric according to the embodiment of the present invention will be described.
The inventors of the present application have diligently studied the composite non-woven fabric, and the basis weight (g / m ² ) and thickness (mm), and the softness of the pulp fiber web side (TS7 value (dBV ² rms)). The composite non-woven fabric designed so that the smoothness (TS750 value (dBV ² rms)) is within a predetermined range is less likely to generate paper dust, and it has been confirmed that it is excellent in usability, and the present invention has been achieved. be. Such a composite nonwoven fabric can be produced by subjecting it to a heat embossing treatment under predetermined conditions after the drying step.

The weight of the composite nonwoven fabric according to the present invention is 52.0 to 88.0 g / m ² , preferably 62.0 to 77.0 g / m ² , and the thickness is 0.28 to 0.47 mm, preferably 0.28 to 0.47 mm. It is set to 0.34 to 0.43 mm. The TS7 value indicating the softness of the pulp fiber web side, which is an important factor for the composite non-woven fabric, is 12.0 to 20.0, preferably 14.5 to 18.2, and is also an important factor. The TS750 value indicating a certain smoothness is set to 33.0 to 71.0, preferably 44.5 to 62.5.

The TS7 value and TS750 value are measured using a tissue softness measuring device TSA (Tissue Software Analyzer). In the tissue softness measuring device TSA, when a rotor with a blade is pressed and rotated from a composite non-woven fabric (sample) placed on a sample table with the pulp surface side facing upward, vibration data detected by various sensors is vibrated. The softness (feel) of non-woven fabrics, etc. is quantitatively evaluated by analyzing and parameterizing (TS value). Is.
In the measurement by the tissue softness measuring device TSA, for example, the vibration of the sample table is measured by a vibration sensor installed inside the sample table, the vibration frequency is analyzed, and the parameterization ( TS value ) is performed. The vibration frequency depends on the structural dimensions such as creeping and embossing and the rotation speed of the blade. The induction of horizontal vibration of the blade itself (resonance frequency: for example, 6500 Hz) occurs due to the momentary interruption by the convex part of the sample and the vibration of the blade as it travels on the surface of the sample. The intensity of the maximum peak of the first spectrum from the low frequency side is the TS750 value (dBV ² rms), and the intensity of the maximum peak of the spectrum including the resonance frequency: 6500 Hz (around 6500 Hz) is the TS7 value (dBV ² rms). do.

The software for vibration analysis and parameterization (TS value) can use the emtec measurement system. This software is equipped with various algorithms (for example, Base Calculation, Financial, TP, etc.), and automatically acquires TS7 and TS750 values on the software, and these TS7 and TS750 values or basis weight, thickness, etc. The HF (hand feel) value is calculated from the number of plies and the like depending on the type of various algorithms. In the present invention, the TS7 value and the TS750 value are defined instead of the HF value, and any algorithm may be used as long as the measurement conditions are satisfied, and the TS7 value and the TS750 value vary depending on the type of algorithm. There is no.

As described above basis weight (g ^{/ m} 2), thickness (mm), as well as the pulp fiber web side softness (TS7 value ^(dBV 2 rms)) for and smoothness (TS750 value ^(dBV 2 rms)) The composite non-woven fabric of the present invention, which is designed to be within a predetermined suitable range, produces less paper dust, has a firm hand-held feel, is not stiff, has an excellent usability, and is water-absorbent. It can be a composite non-woven fabric that is also good in terms of points. The thickness of the composite non-woven fabric can be measured with ^{, for example, a peacock paper thickness gauge under a weight of 37.85 g / cm 2.}
Further, the drip water absorption degree, which is an index of water absorption performance, is set to 0.5 to 3.0 seconds, and the water absorption amount (TWA: Total Water Absorbency) is set to ^{300 to 490 g / m 2.} Some are preferred. The above-mentioned drip water absorption degree is based on the water absorption rate test specified in JIS L 1907, and the time (seconds) from the time when 0.1 ml of water droplet reaches the surface of the test piece until the specular reflection of the test piece disappears. Can be obtained by measurement. Further, the above TWA can be obtained as follows. First, the non-woven fabric is cut into a square of 75 × 75 mm to prepare a sample piece, and the dry weight is measured. Next, after immersing this sample piece in distilled water for 2 minutes, one corner of the sample piece is set to be the upper top in a container saturated with steam, and the two corners adjacent to this top are formed. The sample is hung in a stretched state (100% RH), left for 30 minutes, and the weight after draining is measured. For draining, cut a paper towel to 3 x 38 mm and use it. Then, the measured value can be obtained by converting it into the water retention amount (g / m ^{2 ) per 1 m 2 of the sample piece.}
Further, it is preferable that the wet taber value, which is an index of durability, is designed to be 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 by an abrasive grain conjugate is applied under a specified load to get wet. It preferably has abrasion resistance with a Taber value of at least 5 times.

The basis weight of the pulp fiber web is 40.0 to 70.0 g / m ² , and the weight composition ratio of the spunbonded non-woven fabric and the pulp fiber web is 40/60 to 10/90 (wt%). Is preferable. Those in this range are excellent in water absorption performance and hand-held feeling, and are also excellent in shape stability of the composite non-woven fabric.
The basis weight of the spunbonded non-woven fabric is preferably ^{7.0 to 20.0 g / m 2.} Further, the spunbonded non-woven fabric is formed to include a plurality of fusion points for joining the spun resin fibers, and the area of one fusion point is 0.10 to 0.50 mm ² , and the unit of the fusion point is 0.10 to 0.50 mm 2. It is preferable that the area ratio per area is 7 to 20% and the number is 10 to 150 pieces / cm ^2. Such a spunbonded non-woven fabric has appropriate rigidity and is suitable as a spunbonded non-woven fabric to be used as a composite non-woven fabric in combination with a pulp fiber web. The shape of the fusion point is not particularly limited and may be circular, elliptical, polygonal or the like.

It is desirable that the spunbonded non-woven fabric is formed by one kind selected from the group consisting of nylon, vinylon, polyester, acrylic, polyethylene, polypropylene and polystyrene, or a mixture of two or more kinds. Among these, polypropylene is preferably used.
As for the pulp fiber web, it is preferable to use one formed of fibers of softwood bleached kraft pulp selected from the group consisting of radiata pine, slash pine, southern pine, lodge pole pine, spruce and douglas fur. ..

Hereinafter, the step of manufacturing the composite nonwoven fabric of the present invention described above will be described. The composite nonwoven fabric of the present invention can be efficiently produced by subjecting a predetermined embossing treatment after the drying step. Here, first, the main configuration of the manufacturing apparatus for manufacturing the flat composite non-woven fabric WP will be described, and then the embossing apparatus will be described.

The composite non-woven fabric manufacturing apparatus 1 shown in FIG. 1 is provided with an air-laid apparatus 2, a spunbond supply device 3 for supplying a spunbonded nonwoven fabric, and a suction device 4 on the upstream side. The suction device 4 is arranged so as to face the lower side of the air raid device 2.
Water flow entanglement device 5, suction device 6, drying device 7 that injects a water jet for performing water flow entanglement processing in order from the upstream side downstream of these devices 2, 3 and 4 in the transport direction TD of the web. Is placed. A winding device 8 for winding the continuously manufactured composite non-woven fabric WP is further provided downstream of the drying device 7.

The air-laid device 2 is provided with a defibrating machine 21 for defibrating raw pulp RP in which fibers are densely packed into a sheet into pulp fibers, and a pulp fiber PF defibrated with a blower (not shown) to the air-laid hopper 23. It has a duct 22 for carrying the pulp.

Further, an air-laid hopper 23 is arranged on the downstream side of the duct 22. Inside the air-laid hopper 23, the pulp fibers in the defibrated state are dispersed and lowered, and the pulp fiber web PFW is gradually formed at the stacking position 24 set on the lower surface.
A suction device 4 is provided opposite to the lower side of the stacking position 24. More specifically, the suction device 4 has a suction portion 42 on the upper surface of the apparatus main body 41, and the suction portion 42 has a suction force (negative pressure) on the pulp fiber web PFW with respect to the stacking position 24. It has been set.
Note that FIG. 1 illustrates a case where the pulp fiber web PFW is formed by arranging the air-laid hopper 23 and the suction device main body 41 one by one in one stage. However, the present invention is not limited to this, and the air-laid hopper 23 and the suction device main body 41 may be arranged in two or more stages according to the basis weight (basis weight) and the manufacturing speed of the pulp fiber web PFW.

Further, a transport wire 43 for web transport is arranged around the suction device 4. The transfer wire 43 is arranged so that the pulp fiber web PFW on which the pulp fiber PF is deposited can be placed at the stacking position 24 and is conveyed to the downstream side. However, the pulp fiber web PFW is not placed directly on the transport wire 43. This will become clear in the description below.
The transport wire 43 is formed in an opening form (mesh) so that the suction force of the suction portion 42 extends to the opposite side (upper side).

A spunbond supply device 3 is arranged below the airlaid device 2 and upstream of the suction device 4. A spunbonded non-woven fabric SW prepared in advance is set in the spunbond supply device 3 in a roll shape. The spunbonded non-woven fabric SW is pulled out from the spunbond supply device 3 and is conveyed to the laminated position 24 on the conveying wire 43 described above. As the spunbonded non-woven fabric SW, it is preferable to use a web of continuous filaments of synthetic resin formed by the spunbonding method.

The pulp fiber web PFW described above is placed on the spunbonded non-woven fabric SW located at the lamination position 24. At that time, at the laminated position 24, the suction force by the suction portion 42 of the suction device 4 passes through the transport wire 43 and acts on the spunbonded non-woven fabric SW and the pulp fiber web PFW on the conveying wire 43. Therefore, the preliminary laminated body PWeb in which the spunbonded non-woven fabric SW and the pulp fiber web PFW are laminated is transported to the downstream side.

The preliminary laminated body PWeb described above 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 laminated body PWeb is conveyed and thrown into the water flow confounding device 5 on the downstream side as it is, a part of the pulp fiber PF may be blown up by the water jet (high pressure water flow).
Therefore, in the present manufacturing apparatus 1, the sandwiching roller 28 for stabilizing the placement state of the pulp fiber web PFW on the spunbonded nonwoven fabric SW by sandwiching the preliminary laminated body PWeb from above and below, and the upstream of the water flow confounding apparatus 5. A pre-wet device 30 for applying moisture to prevent fiber scattering is provided on the side. The pre-wet device 30 preferably applies a suction force from the spray nozzle 31 that sprays water mist from above the preliminary laminate PWeb and the lower side of the preliminary laminate PWeb (that is, the lower surface of the pulp fiber web PFW). It is configured to include a suction device 32.
Note that FIG. 1 illustrates a case where the pre-wet device 30 is provided as a new device in front of the water flow confounding device 5 as described above, but the present invention is not limited to this. With respect to a plurality of sets including the water jet head 51 and the suction device 52, which will be described later, included in the water flow confounding device 5, the design may be changed so that the set located at the head is diverted as the pre-wet device 30. In this case, it is sufficient to adjust so that the low-pressure water mist is sprayed from the head water jet head 51.
In the case of the water flow entanglement device 5 in which a sufficient number of sets of the water jet head 51 and the suction device 52 are secured to perform the water flow entanglement process, the head water jet head 51 and the suction device 52 are pre-pressed as described above. Utilizing it as a wet device is effective in controlling the equipment cost.

Then, in the water flow entanglement device 5, the entanglement of the pulp fibers is promoted by spraying a high-pressure water jet on the pretreated laminated body PWeb of the sandwiching roller 28 and the pre-wet device 30 which are the pretreatment portions. This promotes the integration of the pulp fiber web PFW layer located on the upper side and the spunbonded non-woven fabric SW layer located on the lower side.
In the water flow confounding device 5 exemplified in FIG. 1, water jet heads 51 are arranged in multiple stages (four stages are illustrated in FIG. 1) along the transport direction TD.
Note that FIG. 1 does not show the state of the nozzles provided in the water jet head 51 extending in the direction perpendicular to the transport direction TD (the width direction of the web), but a plurality of waters in the width direction. The jet nozzles are located at appropriate positions. The hole diameter φ of this water jet nozzle is preferably 0.06 to 0.15 mm. The distance between the water jet nozzles is preferably 0.4 to 1.0 mm.

It is desirable that the water pressure at the time of performing the water flow entanglement treatment is set in consideration of the basis weight of the pulp fiber web PFW and the spunbond web SW. For example, it is preferable to select in the range of 1 to 30 MPa.

The suction device 52 is arranged so as to face the water jet head 51. While spraying the high-pressure water jet emitted from the water jet head 51 onto the pulp fiber web PFW located on the upper side, the suction force of the suction device 52 is applied to the lower side of the spunbonded non-woven fabric SW located on the lower side. By the cooperative action of the water jet head 51 and the suction device 52, the pulp fiber on the pulp fiber web PFW side has entered the lower spunbonded non-woven fabric SW, or has penetrated the spunbonded non-woven fabric SW to reach the opposite side. It is presumed that a non-woven fabric is formed. The action promotes the integration of the two layers.

The transport wire 55 is also arranged in the water flow entanglement device 5. The transfer wire 55 receives the preliminary laminated body PWeb downstream of the pretreatment units 28 and 30, and transfers the transfer wire 55 into the water flow confounding device 5. The transfer wire 55 is arranged so as to pass between the water jet head 51 of the water flow confounding device 5 and the suction device 52 from the upstream side to the downstream side.
Therefore, the preliminary laminate PWeb transported on the transport wire 55 is subjected to more water flow entanglement processing as it goes downstream in the transport direction TD, and when it leaves the water flow entanglement device 5, the pulp fiber on the upper side is subjected to. Sufficient entanglement treatment between the web PFW layer and the lower spunbonded non-woven fabric SW layer is realized.
The non-woven fabric immediately after leaving the water flow entanglement device 5 is in a wet state, and the bonds between the pulp fibers and the like are not sufficiently established.

Therefore, as shown in FIG. 1, the suction device 6 and the suction device 6 for completing the production of the composite non-woven fabric WP by sucking and removing the water remaining on the web on the downstream side of the water flow confounding device 5 and then drying the web. A drying device 7 is deployed. In this way, if the non-woven fabric is dehydrated and dried by the suction device 6 and the drying device 7 in the subsequent stage of the production of the composite non-woven fabric WP, the non-woven fabric can be efficiently produced, and a large external pressure is applied to the non-woven fabric after water flow entanglement. Since it is possible to produce a non-woven fabric that is completely dry, it is possible to finish the product with a bulky feeling.
The suction device 6 dehydrates the non-woven fabric after water flow confounding, for example, by a vacuum type. It is preferable to use a non-compression type dryer, preferably an air-through dryer, for the drying device 7. In FIG. 1, the rotatable dryer body 71 of the air-through dryer is a tubular body, and a large number of through holes are provided on the peripheral surface thereof, and hot air heated by a heat source (not shown) flows from the outer periphery to the center of the dryer body. It is better to have a configuration that sucks toward the side.
The composite type composite non-woven fabric WP continuously produced in this way is wound by the roller 81 of the winding device 8 to complete a series of steps.

Although a general composite non-woven fabric can be produced by the above steps, the composite non-woven fabric according to the present invention suppresses the generation of paper dust and is an excellent non-woven fabric in terms of usability. Therefore, a heat embossing step of embossing the pulp fiber web PFW side under predetermined conditions after the drying step by the drying apparatus 7 is included. The embossing device EA additionally arranged on the downstream side of the drying device 7 will be described.

FIG. 2 shows the schematic configuration of the embossing device EA on the left side, and schematically shows the state of the embossed composite nonwoven fabric WP on the right side.
The embossing device EA of FIG. 2 includes an upper embossing roll a1 that contacts the pulp fiber web PFW side and a lower plain receiving roll a2. An uneven portion pattern formed on the pulp fiber web PFW is engraved on the outer peripheral surface of the embossed roll a1. On the other hand, the outer peripheral surface of the receiving roll a2 is formed flat.
The embossed roll a1 and the receiving roll a2 have a roll equivalent diameter calculated by the formula (roll equivalent diameter) = (embossed roll diameter) × (receiving roll diameter) / {(embossed roll diameter) + (receiving roll diameter)}. It is desirable to design so that the diameter is 75 to 300 mm, more preferably 100 to 250 mm. The roll equivalent diameter here is based on the literature (1990 TAPPI Finishing and Converting, P5) presented by AV Lyons et al., And is an index of the strength of embossing applied to the composite non-woven fabric. For example, if the roll equivalent diameter is less than 75 mm, it becomes difficult for the embossing applied to the composite nonwoven fabric to enter, while if the roll equivalent diameter is larger than 300 mm, the embossing becomes too strong. In addition, there are problems such as an increase in running cost due to equipment and an increase in installation space.

The roll nip pressure of the embossed roll a1 and the receiving roll a2 is set to 1.0 to 6.0 MPa, more preferably 2.0 to 5.0 MPa. The gap between the rolls is set to 0 to 0.3 mm, and a heating means (for example, a heater) is provided on at least one of the embossed roll a1 and the plain roll a2 so that the temperature of the embossed roll a1 is 80 to 150 ° C. More preferably, it is set to 100 to 135 ° C. Further, it is desirable that the transport speed of the roll is set to be 150 to 280 m / min, more preferably 190 to 260 m / min.
By setting the embossing operating conditions within the above range, appropriate embossing is applied to the pulp surface of the composite non-woven fabric, and paper dust generated when the composite non-woven fabric is used can be reliably suppressed. In this regard, if the roll nip pressure is too low, the gap between the rolls is too wide, the embossed roll temperature is too low, or the transport speed is too fast, the embossing applied to the composite non-woven fabric will be weakened, resulting in paper dust suppression. The effect is reduced (more paper dust is used during use). On the other hand, if the roll nip pressure is too high, the embossed roll temperature is too high, or the transport speed is too slow, the embossing applied to the composite non-woven fabric becomes too strong, damaging the spunbonded non-woven fabric constituting the composite non-woven fabric. In addition, the surface of the pulp fiber web may be roughened, and in this case as well, the amount of paper dust during use increases. Therefore, it is important to set it in the above-mentioned suitable range.
The materials of the embossing roll a1 and the receiving roll a2 are not particularly limited, but it is preferable to use a metal roll for both of them.
With the embossing device EA set to satisfy the above conditions, a suitable uneven portion pattern can be formed on the pulp fiber web PFW by heat embossing treatment of heat crimping. The surface of the spunbonded non-woven fabric SW (the back side of the composite non-woven fabric WP) located on the lower side is in contact with the receiving roll a2 and thus becomes flat.

Further, FIG. 3 is a diagram shown for explaining the form of the embossing roll that is preferably adopted in the embossing device EA. FIG. 3A or FIG. 3B is an enlarged cross-sectional view showing a part of the surface fa of the embossing roll a1, and a plurality of embossed convex portions EP for forming embossing are formed on the surface fa. Existing. As shown in FIG. 3A, the area of the root portion and the area of the tip portion are the same, and as shown in FIG. 3B, the area of the root portion and the area of the tip portion are different. can. The height EH of the embossed convex portion from the surface fa to the tip portion is preferably set to 0.2 to 1.0 mm, preferably 0.4 to 0.8 mm.
FIG. 3C is an enlarged plan view showing a part of the surface fa of the embossed roll a1. In FIG. 3C, the area of the embossed portion, which is the ratio of the area where the convex portion EP exists (the total area of the root portions) to the total area of the surface fa (indicated by the rectangular area here). The rate is preferably set to 2.0 to 15.0%, more preferably 4.0 to 12.0%.
By setting the embossing height and area ratio within the above ranges, appropriate embossing is applied to the pulp surface of the composite non-woven fabric, and paper dust generated when the composite non-woven fabric is used is suppressed.
The shape (cross-sectional shape) and arrangement of the embossed convex portions EP are not particularly limited, but the shape may be a round shape as shown in FIG. 3 (c), or a polygonal shape or a star. Shapes can be adopted. The arrangement may be an aligned type as shown in FIG. 3 (c), or may be a staggered type.

In the composite non-woven fabric manufacturing apparatus shown in FIG. 1, an embossing apparatus EA designed in accordance with the above conditions on the downstream side of the drying apparatus 7 is used to emboss the pulp fiber web PFW to form a composite having the above-described configuration. The molded non-woven fabric can be efficiently manufactured, and the manufactured composite non-woven fabric can be a composite non-woven fabric having less paper dust and excellent usability.
By embossing the composite non-woven fabric WP according to the present invention, the fibers protruding from the surface can be leveled (laid down), whereby the generation of paper dust can be suppressed. Further, since the pressing force applied to the pulp fiber web PFW is much lower than that in the case of processing using the calendar device, damage to the surface of the composite nonwoven fabric can be reduced. More specifically, when the embossing device EA as shown in FIG. 2 is adopted as compared with the case of processing using the calendar device, the thickness of the non-embossed portion remains almost uncrushed (that is, the non-embossed portion). The height of the composite non-woven fabric of the present invention is almost the same as that before the embossing treatment), so that the composite non-woven fabric of the present invention can be obtained, which has a feature that the hand-held feeling (firm feeling) and water absorption are not impaired.

Note that FIG. 1 exemplifies the case where the embossing device EA shown in FIGS. 2 and 3 is added online, and it is preferable to provide the embossing device EA integrally with the non-woven fabric wiper manufacturing device in this way. However, it is also possible to once wind the non-woven fabric wiper WP around the roller 81 and perform the embossing process offline with the embossing device EA provided separately.

(Example)
Hereinafter, the composite nonwoven fabric of the example manufactured by embossing with the above manufacturing apparatus will be described.
The composite non-woven fabrics of Examples 1 to 5 and Comparative Examples 1 to 7 manufactured so that the TS7 value indicating the basis weight, the thickness and the softness and the TS750 value indicating the smoothness are as shown in Table 1. Based on the criteria shown below, sensory evaluation was performed on the small amount of fallen fibers when using the composite non-woven fabric (dry state), the feeling of holding (firmness), the feeling of holding (not stiff), and the water absorption.
1) Low amount of deciduous fibers: Deflated fibers when using composite non-woven fabric (dry state) Almost no deciduous fibers are seen (excellent ◎), and although deciduous fibers are slightly observed, they can be used without problems (good ○). , Difficult to use due to many fallen fibers (impossible ×)
2) Hand-held feeling (firm feeling): Hand-held feeling when using composite non-woven fabric (excellent ◎), level that can be used without problems (good ○), feels fluent, and is uncomfortable to wipe (impossible ×)
3) Hand-held feeling (not stiff): Hand-held feeling when using composite non-woven fabric Moderately supple and comfortable to wipe (excellent ◎), level that can be used without problems (good ○), feels stiff and stiff, and is uncomfortable to wipe (excellent) Impossible ×)
4) Water absorption: Sensory evaluation of water absorption when using composite non-woven fabric Water absorption method, water absorption amount is particularly excellent (excellent ◎), no problem level (good ○), water absorption is poor and usability Inferior (impossible ×)

As shown in Table 1 above, Examples 1 to 5 can be provided as products, but as shown in Table 2 above, in Comparative Examples 1 to 7, there are few fallen fibers, a feeling of holding (firmness), and holding. It was impossible because of either the feeling (not stiff) or the water absorption.

In Examples 1 to 5, the basis weight is 52.0 to 88.0 g / m ² , the thickness is 0.28 to 0.47 mm, and the ^{TS7 value indicating softness is 12.0 to 20.0 dBV 2 rms and} The TS750 value indicating smoothness is in the preferable range of ^{33.0 to 71.0 dBV 2 rms.}

On the other hand, in Comparative Example 1, it was confirmed that not only the thickness and smoothness (TS750 value) were out of the preferable range but also the water absorption and durability were low due to the calendar processing, and the sensory evaluation was performed accordingly. ing.
Further, in Comparative Example 2, it was confirmed that the basis weight and the thickness were less than the preferable range, and the water absorption and durability were also low, and the sensory evaluation was performed accordingly.
Further, in Comparative Example 3, the basis weight and the thickness exceed the preferable ranges. As a result, it can be confirmed that the sensory evaluation of the hand-held feeling (not stiff) is inferior.

Further, in Comparative Examples 4 to 7, even if the basis weight and the thickness are in the above-mentioned preferable ranges, if the conditions in the embossing treatment are not suitable, the softness (TS7 value) or the smoothness (TS750 value) is in the preferable range. However, it can be confirmed that the fibers (paper dust) that fall off correspondingly cannot be reliably suppressed.
The embossed roll in the embossing process has an area ratio of the embossed portion of 2.0 to 15.0%, an embossed height of 0.2 to 1.0 mm, a roll equivalent diameter of 75 to 300 mm, and a transport speed of 150 to 280 m. The preferred range is / min. However, the embossed roll of Comparative Example 4 is less than the above-mentioned suitable range or exceeds the above-mentioned suitable range. Also in Comparative Example 5, the embossing roll exceeds the above-mentioned suitable range or is less than the above-mentioned suitable range.

Further, in the embossing treatment, it is preferable that the gap between the rolls is 0 to 0.3 mm, the roll nip pressure is 1.0 to 6.0 MPa, and the temperature of the embossed roll is 80 to 150 ° C. However, in Comparative Example 6, the embossing treatment was performed below the above-mentioned suitable range, and in Comparative Example 7, the embossing treatment was performed beyond the above-mentioned suitable range.

Considering the contents shown in Tables 1 and 2 as a whole, the roll equivalent diameter in the embossing process is too small, the transport speed is too fast, the inter-roll gap (Gap) is too large, and the roll nip pressure is too small. If the temperature is too low, the force applied to the surface of the composite non-woven fabric is small, so that the effect of leveling the protruding pulp fibers is insufficient, and it can be confirmed that the effect of suppressing paper dust is small. The state of protruding onto the surface of the composite non-woven fabric can be evaluated by the TS7 value, and when there are many protruding fibers, the TS7 value becomes larger than the preferable range, and the amount of paper dust during use increases.

On the other hand, if the equivalent roll diameter in the embossing treatment is too large, the transport speed is too slow, the roll nip pressure is too large, the temperature is too high, etc., the force applied to the surface of the composite non-woven fabric becomes too large, and the pulp The fibers are damaged (they tend to harden due to the effects of heat, etc.). In this case as well, there is a demerit that paper dust is likely to be generated. The TS750 value can be used to evaluate the cured fiber. When the fiber is hard and the surface property is poor, the TS750 value becomes larger than the preferable range, and the amount of paper dust during use increases.

Although the description of the embodiment is completed above, it is needless to say that the present invention is not limited to the above embodiment and can be variously modified and implemented without departing from the gist thereof.

1 Composite non-woven fabric manufacturing equipment 2 Air-laid equipment 3 Spunbonded non-woven fabric supply equipment 4 Suction equipment 5 Water flow entanglement equipment 6 Suction equipment 7 Drying equipment 8 Winding equipment 21 Fiber defibrator 22 Duct 23 Air-laid hopper 24 Laminating position 28 Holding roller 30 Pre-wet Device 31 Spray nozzle 32 Suction device 41 Suction device body 42 Suction section 43 Transport wire 51 Water jet head 52 Suction device 55 Transport wire SW Spunbond non-woven fabric PF Pulp fiber PFW Pulp fiber web PWeb Preliminary laminate (laminated web)
WP composite non-woven fabric TD transport direction EA embossing device a1 embossing roll a2 receiving roll

Claims (9)

A composite non-woven fabric in which a pulp fiber web is laminated and integrated on a spunbonded non-woven fabric.
The basis weight is 52.0 to 88.0 g / m ^{2, the} thickness is 0.28 to 0.47 mm, and the TS7 value indicating the softness of the pulp fiber web side is 12.0 to 20.0 dBV ^2. A composite non-woven fabric characterized by a TS750 value indicating rms and smoothness of 33.0 to 71.0 dBV ^{2 rms.} The composite non-woven fabric according to claim 1, wherein the drip water absorption degree is 0.5 to 3.0 seconds, and the water absorption amount (TWA) is 300 to 490 g / m ^2. The composite nonwoven fabric according to claim 1 or 2, wherein the wet taber value is 5 times or more. The basis weight of the pulp fiber web is 40.0 to 70.0 g / m ² , and the weight composition ratio of the spunbonded nonwoven fabric and the pulp fiber web is 40/60 to 10/90 (wt%). The composite nonwoven fabric according to any one of claims 1 to 3, characterized in that. The spunbonded nonwoven fabric has a basis weight of 7.0 to 20.0 g / m ² , and the spunbonded nonwoven fabric is formed to include a plurality of fusion points for joining spun resin fibers. The area of one landing point is 0.10 to 0.50 mm ² , the area ratio of the fusion point per unit area is 7 to 20%, and the number is 10 to 150 pieces / cm ^2. The composite nonwoven fabric according to any one of claims 1 to 4. From claim 1, the spunbonded nonwoven fabric is formed of one kind selected from the group consisting of nylon, vinylon, polyester, acrylic, polyethylene, polypropylene and polystyrene, or a mixture of two or more kinds. 5. The composite non-woven fabric according to any one of 5. The pulp fiber web comprises fibers of softwood bleached kraft pulp selected from the group consisting of radiata pine, slush pine, southern pine, lodge pole pine, spruce and douglas fur. The composite type non-woven fabric according to any one. A method for manufacturing a composite non-woven fabric in which a pulp fiber web is laminated on a spunbonded non-woven fabric and integrated.
It includes at least a water flow entanglement step of promoting the integration of the pulp fiber web and the spunbonded non-woven fabric to obtain a laminate, and a drying step of drying the laminate after the water flow entanglement step.
A heat embossing step of applying a heat embossing treatment to the pulp fiber web side after the drying step is further included.
In the thermal embossing step, the composite is produced by using an embossing roll having an area ratio of the embossed portion of 2.0 to 15.0% and an embossing height of 0.2 to 1.0 mm. Manufacturing method of mold non-woven fabric. In the thermal embossing step, the roll equivalent diameter calculated by the formula (roll equivalent diameter) = (embossing roll diameter) × (receiving roll diameter) / {(embossing roll diameter) + (receiving roll diameter)} is 75 to 300 mm. Using a certain embossed roll and receiving roll, the transport speed is 150 to 280 m / min, the gap between the rolls is 0 to 0.3 mm, the roll nip pressure is 1.0 to 6.0 MPa, and the temperature of the embossed roll is 80 to 150 ° C. The method for producing a composite type non-woven fabric according to claim 8, wherein the composite type non-woven fabric is set in 1.

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