WO2013145841A1

WO2013145841A1 - Nonwoven fabric and production method for nonwoven fabric

Info

Publication number: WO2013145841A1
Application number: PCT/JP2013/052054
Authority: WO
Inventors: 孝義小西; 利夫平岡; 努白井
Original assignee: ユニ・チャーム株式会社
Priority date: 2012-03-30
Filing date: 2013-01-30
Publication date: 2013-10-03
Also published as: JP5755173B2; JP2013209765A; TWI597400B; TW201400661A

Abstract

Provided are a nonwoven fabric that is capable of suitably removing dirt when used to wipe in the machine direction or in the width direction of said nonwoven fabric, and a production method for the nonwoven fabric. The production method for nonwoven fabric of the present invention includes: a step (12) in which a stream of high-pressure water is sprayed on a paper layer in order to form concave sections on the surface of said paper layer that extend in the machine direction and are arranged intermittently in the width direction; a step (20) in which the paper layer on which the stream of high-pressure water was sprayed is dried so as to have a water content of 10-45% or less by adhering the paper layer on which the stream of high-pressure water was sprayed to the surface of a rotating cylindrical dryer; a step (26) in which crepe is formed on the paper layer by separating the paper layer that is adhered to the surface of the cylindrical dryer from said surface using a doctor blade; and a step (14) in which grooves are formed on the surface of the paper layer while leaving the crepe that is formed on the paper layer intact by spraying high-pressure steam from a steam nozzle on the paper layer having crepe formed thereon. The nonwoven fabric of the present invention is produced using the abovementioned production method.

Description

Nonwoven fabric and method for producing nonwoven fabric

The present invention relates to a nonwoven fabric, and particularly to a nonwoven fabric suitable for wipes. Moreover, this invention relates to the manufacturing method of the said nonwoven fabric.

A fiber sheet having a moisture content of 50 to 85% by weight is transferred to an aperture pattern net that circulates along the suction part, and the fiber sheet is sucked in a state where the fiber sheet is held on the aperture pattern net, Simultaneously with the suction or before and after the suction, water vapor having a calorie of 5 kcal / kg or more is sprayed on the fiber sheet to form a pattern corresponding to the aperture pattern net on the fiber sheet and dried in the drying step. A bulky paper manufacturing method characterized by obtaining a patterned bulky paper is known as a conventional technique (for example, Patent Document 1). The bulky paper produced by this production method is used as wipes for cooking paper, paper towels, tissues, and the like. According to this method for producing a bulky paper, it is possible to produce a bulky paper having a large thickness, a high absorbency, excellent softness, and appropriate strength.

JP 2000-34690 A

When using a non-woven fabric as a wipe, it is important to be able to remove dirt well when wiping, in addition to having a large thickness, high absorbency, excellent softness and moderate strength. In particular, since the user uses the wipe without being aware of the machine direction and the width direction of the wipe, whether the direction in which the object is wiped using the wipe is the machine direction of the wipe or the width direction of the wipe is determined. Regardless, it is important that the wipes can remove dirt well.

The object of the present invention is to provide a nonwoven fabric and a method for producing the nonwoven fabric that can well remove dirt, regardless of whether the wiping direction is the machine direction of the nonwoven fabric or the width direction.

The present invention employs the following configuration in order to solve the above problems.
That is, in the method for producing a nonwoven fabric of the present invention, a papermaking raw material containing moisture is supplied onto a belt moving in one direction, a paper layer is formed on the belt, and a high-pressure water stream is jetted onto the paper layer. The step of forming concave portions extending in the machine direction and intermittently arranged in the width direction on the surface and the paper layer sprayed with the high pressure water flow adhered to the surface of the rotating cylindrical dryer A step of drying the sprayed paper layer to a moisture content of 10 to 45% and a paper layer adhered to the surface of the cylindrical dryer by separating the paper layer from the surface through a doctor blade. A crepe having a width larger than the width of the recess and extending in the machine direction by injecting high-pressure steam from the steam nozzle onto the paper layer on which the crepe has been formed. While leaving the paper layer And forming on the surface.
Further, the nonwoven fabric of the present invention includes a longitudinal direction, a transverse direction intersecting the longitudinal direction, a thickness direction perpendicular to the longitudinal direction and the transverse direction, and one surface perpendicular to the thickness direction. The other surface facing the one surface in the thickness direction, extending in the vertical direction on one surface and arranged in the horizontal direction, and on one surface and the other surface A crepe extending in the direction and aligned in the longitudinal direction.

According to the present invention, it is possible to obtain a non-woven fabric that can well remove dirt, regardless of whether the wiping direction is the machine direction of the non-woven fabric or the width direction.

FIG. 1 is a diagram for explaining a nonwoven fabric manufacturing apparatus used in a method for manufacturing a nonwoven fabric according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of a high-pressure water flow nozzle. FIG. 3 is a diagram illustrating an example of a nozzle hole of a high-pressure water flow nozzle. FIG. 4 is a diagram for explaining the principle that the fibers in the paper layer are entangled by the high-pressure water flow. FIG. 5 is a schematic cross-sectional view in the width direction of a paper layer onto which a high-pressure water stream has been jetted. FIG. 6 is a diagram illustrating an example of a high-pressure steam nozzle. FIG. 7 is a view showing an example of a nozzle hole of a high-pressure steam nozzle. FIG. 8 is a diagram for explaining the principle that the fibers of the paper layer are loosened by the high-pressure steam and the bulk of the paper layer is increased. FIG. 9 is a schematic perspective view of a part of the paper layer on which the high-pressure steam is jetted. FIG. 10 is a photomicrograph showing the surface of the nonwoven fabric in one embodiment of the present invention.

Hereinafter, a method for producing a nonwoven fabric according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a view for explaining a nonwoven fabric manufacturing apparatus 1 used in a nonwoven fabric manufacturing method according to an embodiment of the present invention.

A papermaking raw material containing moisture such as fiber suspension is supplied to the raw material supply head 11. The papermaking raw material supplied to the raw material supply head 11 is supplied from the raw material supply head 11 onto the paper layer forming belt of the paper layer forming conveyor 16 and deposited on the paper layer forming belt. The paper layer forming belt is preferably a support having air permeability through which steam can pass. For example, a wire mesh, a blanket, etc. can be used as a paper layer forming belt.

As a fiber used for the papermaking raw material supplied to the raw material supply head 11, for example, a short fiber having a fiber length of 20 mm or less is preferable. Such short fibers include, for example, wood pulp such as soft and hardwood chemical pulp, semi-chemical pulp and mechanical pulp, mercerized pulp and cross-linked pulp obtained by chemically treating these wood pulp, and non-wood fibers such as hemp and cotton. And cellulosic fibers such as regenerated fibers such as rayon fibers, and synthetic fibers such as polyethylene fibers, polypropylene fibers, polyester fibers and polyamide fibers. The fibers used for the papermaking raw material are particularly preferably cellulosic fibers such as wood pulp, non-wood pulp, and rayon fiber.

The papermaking raw material deposited on the paper layer forming belt is appropriately dehydrated by the suction box 15 to form the paper layer 23. The paper layer 23 includes two high-pressure water flow nozzles 12 disposed on the paper layer formation belt and two suction boxes 15 disposed at positions facing the high-pressure water flow nozzle 12 with the paper layer formation belt interposed therebetween. Pass between. The high-pressure water flow nozzle 12 injects a high-pressure water flow onto the paper sheet 23. The suction box 15 sucks and collects the water sprayed from the high-pressure water flow nozzle 12. A high pressure water stream is jetted from the high pressure water stream nozzle 12 onto the paper layer 23, and a recess is formed on the surface of the paper layer 23.

An example of the high-pressure water flow nozzle 12 is shown in FIG. The high-pressure water flow nozzle 12 injects a plurality of high-pressure water flows 31 arranged in the width direction (CD) of the paper layer 23 toward the paper layer 23. As a result, a plurality of recesses 32 that are intermittently arranged in the width direction (CD) of the paper layer 23 and extend in the machine direction (MD) are formed on the surface of the paper layer 23.

An example of the nozzle hole of the high-pressure water flow nozzle 12 is shown in FIG. The nozzle holes 121 of the high-pressure water flow nozzle 12 are arranged in a line in the width direction (CD) of the paper layer, for example. The hole diameter of the nozzle hole 121 is preferably 90 to 150 μm. When the hole diameter of the nozzle hole 121 is smaller than 90 μm, the nozzle may be easily clogged. When the hole diameter of the nozzle hole 121 is larger than 150 μm, the processing efficiency may be deteriorated.

The hole pitch of the nozzle holes 121 (the distance between the centers of holes adjacent in the width direction (CD)) is preferably 0.5 to 1.0 mm. When the hole pitch of the nozzle holes 121 is smaller than 0.5 mm, the pressure resistance of the nozzles is lowered and may be damaged. Further, when the hole pitch of the nozzle holes 121 is larger than 1.0 mm, fiber entanglement may be insufficient.

When the paper layer 23 receives a high-pressure water flow, as shown in FIG. 2, a recess 32 is formed in the paper layer 23 and the fibers of the paper layer 23 are entangled with each other, and the strength of the paper layer 23 is increased. The principle that the fibers of the paper layer 23 are entangled when the paper layer 23 receives a high-pressure water flow will be described with reference to FIG. However, this principle does not limit the present invention.

As shown in FIG. 4, when the high pressure water flow nozzle 12 jets the high pressure water flow 31 onto the paper layer 23, the high pressure water flow 31 passes through the paper layer 23 and the paper layer forming belt 41. As a result, the fibers of the paper layer 23 are drawn toward the portion 42 where the high-pressure water flow 31 passes through the paper layer forming belt 41. As a result, the fibers of the paper layer 23 gather toward the portion 42 where the high-pressure water stream 31 passes through the paper layer forming belt 41, and thereby the fibers are entangled.

The strength of the paper layer 23 is increased when the fibers of the paper layer 23 are entangled with each other. Thereby, even if high-pressure steam is jetted onto the paper layer 23 in a later step, the paper layer 23 is less likely to be pierced, the paper layer 23 is torn, or blown away. Further, the wet strength of the paper layer 23 can be increased without adding a paper strength enhancer to the papermaking raw material.

FIG. 5 shows a schematic diagram of a cross-section in the width direction of the paper layer 23 at a position after passing between the two high-pressure water flow nozzles 12 and the two suction boxes 15 (position 24 in FIG. 1). . A recess 32 is formed on the surface of the paper layer 23 by the high-pressure water flow. A pattern (not shown) corresponding to the pattern of the paper layer forming belt is formed on the surface opposite to the surface on which the high-pressure water flow is jetted.

Thereafter, as shown in FIG. 1, the paper layer 23 is transferred to the paper layer transport conveyor 18 by the suction pickup 17. Further, the paper layer 23 is transferred to the paper layer conveying conveyor 19 and then transferred to the drying dryer 20.

The drying dryer 20 dries the paper layer 23 on which the high-pressure water stream is jetted. For example, a Yankee dryer is used as the drying dryer 20. The drying dryer 20 includes a rotating cylindrical dryer, and the surface of the cylindrical dryer is heated to about 160 ° C. by steam or the like. The drying dryer 20 attaches the paper layer 23 to the surface of the rotating cylindrical dryer, and dries the paper layer 23.

The dry dryer 20 dries the paper layer 23 so that the moisture content is preferably 10 to 45%, more preferably 20 to 40%. Here, the moisture content is the amount of water contained in the paper layer when the dry mass of the paper layer 23 is 100%.

When the moisture content of the paper layer 23 is smaller than 10%, the hydrogen bonding force between the fibers of the paper layer 23 becomes strong, and the energy required to loosen the fibers of the paper layer 23 by high-pressure steam described later becomes very high. There is a case. Further, when the moisture content of the paper layer 23 is less than 10%, the adhesion of the paper layer 23 to the surface of the cylindrical dryer is weakened, and the crepe cannot be formed on the paper layer 23 by the process of forming a crepe described later. There is.

On the other hand, when the moisture content of the paper layer 23 is greater than 45%, the energy required for drying the paper layer 23 to a predetermined moisture content or less by high-pressure steam described below may become very high. Moreover, when the moisture content of the paper layer 23 is larger than 45%, the hydrogen bonding force between fibers in the paper layer becomes weak. As a result, the crepe formed on the paper layer 23 in the step of forming the crepe described later is deformed by the tension applied to the paper layer 23, or the strength of the paper layer 23 is greatly reduced during the crepe formation. May be torn.

As shown in FIG. 1, the paper layer 23 adhering to the surface of the rotating cylindrical dryer in the drying dryer 20 is separated from the surface of the cylindrical dryer via the doctor blade 26. At this time, a crepe extending in the width direction (CD) direction and arranged in the machine direction (MD) is formed on the paper layer 23. The paper layer 23 adhering to the surface of the cylindrical dryer is separated from the surface of the cylindrical dryer after colliding with the end surface of the doctor blade 26 in contact with the surface of the cylindrical dryer. By this collision, the paper layer 23 is bent so that the cross-sectional shape in the machine direction (MD) becomes wavy, and a crepe is formed in the paper layer 23.

The crepe rate of the crepe formed on the paper layer 23 is preferably 5 to 50%. If the crepe rate of the crepe formed on the paper layer 23 is less than 5%, the wiping property in the machine direction (MD) of the nonwoven fabric may not be improved so much. If the crepe rate of the crepe formed on the paper layer 23 is greater than 50%, it may be difficult to form the groove portion uniformly in the paper layer on which the crepe is formed, and the production rate is less than half, resulting in poor productivity. It may become.

The crepe rate of the paper layer 23 can be measured, for example, as follows.
(1) A measurement sample having a machine direction (MD) length of 150 mm and a width direction (CD) length of 50 mm is cut out from the paper layer on which the crepe is formed.
(2) A straight line having a length of 100 mm extending in the machine direction (MD) is drawn on the surface of the cut out measurement sample in the width direction (CD) center using an oil-based ballpoint pen or the like. When drawing this straight line, be careful not to tear the paper layer.
(3) The measurement sample is immersed in water for 10 seconds.
(4) A measurement sample is taken out of water and placed on a glass plate. Then, the measurement sample is stretched in the machine direction (MD) until the crepe of the paper layer disappears.
(5) The length A (mm) in the machine direction (MD) of the straight line drawn on the stretched measurement sample is measured.
(6) The crepe rate is calculated from the following equation.
Crepe rate (%) = (A-100) / A × 100
(7) Repeat (3) to (6) two more times for the same measurement sample.
(8) The average value of the calculated three crepe rates is defined as the crepe rate of the paper layer.

Next, as shown in FIG. 1, the paper layer 23 on which the crepe is formed moves onto the mesh-shaped outer peripheral surface of the cylindrical suction drum 13. At this time, high-pressure steam is jetted onto the paper layer 23 from one steam nozzle 14 disposed above the outer peripheral surface of the suction drum 13. The suction drum 13 has a built-in suction device, and water vapor ejected from the steam nozzle 14 is sucked by the suction device. Due to the high-pressure steam jetted from the steam nozzle 14, a groove portion having a width larger than the concave portion formed by the high-pressure water flow is formed on the surface of the paper layer 23.

The surface of the paper layer 23 that ejects high-pressure water vapor is preferably the surface opposite to the surface that ejected high-pressure water flow. Compared with the fibers of the paper layer 23 on the surface opposite to the surface on which the high-pressure water flow is injected, the fibers of the paper layer 23 on the surface on which the high-pressure water flow is injected are strongly entangled, and the fibers in the paper layer are loosened by the high-pressure steam. This is because more energy is required.

The high-pressure steam sprayed from the steam nozzle 14 may be steam composed of 100% water, or steam containing other gas such as air. However, the high-pressure steam sprayed from the steam nozzle 14 is preferably steam composed of 100% water.

The temperature of the high-pressure steam is preferably 105 to 220 ° C. As a result, the drying of the paper layer 23 proceeds even when high-pressure steam is sprayed onto the paper layer 23, and the paper layer 23 dries at the same time as the bulk increases. When the paper layer 23 is dried, the hydrogen bonds between the fibers of the paper layer 23 are strengthened, so that the strength of the paper layer 23 is increased and the increased bulk of the paper layer 23 is less likely to be crushed, and the crepe formed in the paper layer 23 Becomes difficult to disappear. Further, since the strength of the paper layer 23 is increased, it is possible to prevent the paper layer 23 from being pierced or cut due to the jet of high-pressure steam.

An example of the steam nozzle 14 arranged above the suction drum 13 is shown in FIG. The steam nozzle 14 injects a plurality of high-pressure steams 51 arranged in the machine direction (MD) and the width direction (CD) of the paper layer 23 toward the paper layer 23 on which the crepe 52 is formed. As a result, a plurality of grooves 53 extending in the machine direction (MD) along the width direction of the paper layer 23 are formed on the upper surface of the paper layer 23. As described above, the width of the groove 53 is larger than the width of the recess 32 (see FIG. 2) formed by the high-pressure water flow 31.

FIG. 7 is a view showing an example of the nozzle hole 141 of the high-pressure steam nozzle 14. Like the steam nozzle 14 shown in FIG. 7, the nozzle hole rows of the plurality of nozzle holes 141A arranged in the width direction (CD) are arranged in three rows in the machine direction (MD). Therefore, as shown in FIG. 6, the plurality of high-pressure steams 51 arranged in the width direction (CD) are arranged in three rows in the machine direction (MD). The number of nozzle hole rows of the plurality of nozzle holes arranged in the width direction (CD) is not limited to 3, but may be 1, 2 and 4 or more. Further, by arranging a plurality of high-pressure steam nozzles in the machine direction (MD), a nozzle hole row of a plurality of nozzle holes arranged in the width direction (CD) may be arranged in the machine direction (MD). In addition, by arranging the nozzle holes so that a plurality of nozzle hole rows of the plurality of nozzle holes arranged in the width direction (CD) are arranged in the machine direction (MD), the groove portion can be reliably formed in the paper layer. This makes it possible to reliably increase the bulk of the paper layer.

The diameter of the nozzle hole of the steam nozzle 14 is preferably 150 to 500 μm. When the hole diameter of the nozzle hole is smaller than 150 μm, energy may be insufficient and the fibers may not be sufficiently scraped. On the other hand, if the hole diameter of the vapor nozzle 14 is larger than 500 μm, the energy may be too large and the substrate damage may become too large.

The nozzle hole hole pitch (distance between the centers of nozzle holes adjacent in the width direction (CD)) is preferably 3.0 to 7.0 mm. When the hole pitch of the nozzle holes is smaller than 3.0 mm, the interval in the width direction (CD) of the adjacent high-pressure steam becomes too small, and the crepe formed in the paper layer 23 by the high-pressure steam having a small mutual interval is used. Most of them may be drowned out. On the other hand, when the hole pitch of the nozzle holes is larger than 7.0 mm, the bulk of the paper layer 23 is not so high, and the effect of improving the flexibility of the paper layer 23 by high-pressure steam may be reduced.

The vapor pressure of the high-pressure steam injected from the steam nozzle 14 is preferably 0.2 to 1.5 MPa. If the vapor pressure of the high-pressure steam is smaller than 0.2 MPa, the bulk of the paper layer 23 may not be so high due to the high-pressure steam. Further, when the vapor pressure of the high-pressure steam is higher than 1.5 MPa, a hole may be formed in the paper layer 23, or the paper layer 23 may be torn or blown off. In addition, since the fiber of the paper layer 23 is loosened when the crepe is formed on the paper layer 23, the bulk of the paper layer 23 can be increased by the high-pressure steam having a low vapor pressure as compared with the case where the crepe is not formed.

When high-pressure steam is jetted onto the paper layer 23, the fibers of the paper layer 23 are loosened and the bulk of the paper layer 23 is increased. Thereby, the softness | flexibility of the paper layer 23 increases and the tactile sense of the paper layer 23 is improved. When the paper layer 23 receives high-pressure water vapor, the principle of loosening the fibers of the paper layer 23 and increasing the bulk of the paper layer 23 will be described with reference to FIG. However, this principle does not limit the present invention.

As shown in FIG. 8, when the steam nozzle 14 ejects the high-pressure steam 51, the high-pressure steam 51 hits the suction drum 13. Most of the high-pressure steam 51 is returned to the suction drum 13. As a result, the fibers of the paper layer 23 are rolled up and loosened. Then, the loosened fibers of the paper layer 23 are scraped by the high-pressure steam 51, and a groove is formed in the paper layer 23. The separated fibers gather as the high-pressure water vapor 51 moves to the width direction side of the portion 54 corresponding to the paper layer 23 and the bulk of the paper layer 23 increases. Further, the moisture contained in the paper layer 23 is evaporated by the heat of the high-pressure steam 51 and is removed from the paper layer 23. Thereby, the drying of the paper layer 23 proceeds.

In the method for producing a nonwoven fabric according to an embodiment of the present invention, a groove is formed in the paper layer with high-pressure steam in order to increase the bulk of the paper layer. Therefore, in order to increase the amount of fibers scraped by the high pressure steam, the width of the groove formed by the high pressure steam is larger than the width of the recess formed by the high pressure water flow.

Since the fibers in the paper layer are loosened at the portion where the high-pressure steam is injected, the crepe is reduced or eliminated on the inner surface of the groove. Thereby, in the part of the surface of a groove part, a paper layer becomes difficult to extend in a machine direction (MD) compared with the other part in which a crepe remains. Therefore, the groove portion of the paper layer suppresses the crepe of the paper layer from extending and disappearing, and becomes a fixed portion for maintaining the shape of the crepe. Thereby, even if the manufactured nonwoven fabric becomes a wet state, the nonwoven fabric can hold a crepe. Further, as described above, since the crepe was formed on the dried paper layer 23 so as to have a moisture content of 10 to 45% or less, the crepe was firmly formed on the paper layer 23, and the paper layer 23 was formed by the high-pressure steam described above. Even if the fibers are loosened, the crepe formed in the paper layer 23 is held except for the portion on the surface of the groove.

FIG. 9 is a schematic perspective view of a part of the paper layer 23 (position 25 in FIG. 1) on which high-pressure steam has been jetted. The paper layer 23 includes a longitudinal direction, a transverse direction intersecting the longitudinal direction, a thickness direction perpendicular to the longitudinal direction and the transverse direction, one surface perpendicular to the thickness direction, The other surface facing the surface in the thickness direction, extending in the longitudinal direction on one surface, and arranged in the lateral direction, and in the lateral direction on one surface and the other surface. And a crepe 52 extending in the vertical direction. Here, the vertical direction corresponds to the machine direction (MD), and the horizontal direction corresponds to the width direction (CD). On one side, the crepe 52 is provided between adjacent grooves 53.

In the paper layer 23, a region 55 on the surface side where a plurality of concave portions 32 formed by high-pressure water flow exists is a region where the strength of the paper layer 23 is high, and a region on the surface side where the groove 53 is formed by high-pressure steam. Reference numeral 56 denotes a region where the paper layer 23 has a high bulk although the strength of the paper layer 23 is slightly weaker than the region 55 due to the high-pressure steam. As described above, by forming the strong region 55 and the weakly strong region 56 in the paper layer 23, the strength and bulkiness of the paper layer 23 can be balanced. That is, this makes it possible to form a paper layer 23 that is bulky and has high strength.

As shown in FIG. 9, the crepe 52 is hardly visible on the inner surface of the groove 53, but the crepe remains between the adjacent grooves 53. Further, the crepe 52 (not shown) remains on the surface where the recess 32 is formed by the high-pressure water flow.

When the nonwoven fabric is moved in the width direction (CD) and the dirt is wiped off, the grooves 53 can wipe off the dirt. Therefore, the groove part 53 formed in the nonwoven fabric improves the ability to wipe off the dirt in the nonwoven fabric when the nonwoven fabric is moved in the width direction (CD) of the nonwoven fabric to wipe off the dirt.

When the nonwoven fabric is moved in the machine direction (MD) and the dirt is wiped off, the dirt can be scraped off by the crepe 52 of the nonwoven fabric. Therefore, the nonwoven fabric crepe 52 improves the ability to wipe off dirt in the nonwoven fabric when the nonwoven fabric is moved in the machine direction (MD) of the nonwoven fabric to wipe away the dirt.

Compared with the case where the paper layer 23 in a flat state is loosened with high-pressure steam, the paper layer 23 is easily raised when the corrugated (bellows-like) paper layer 23 is loosened with high-pressure steam. By forming a crepe on the paper layer 23, the paper layer 23 can be loosened by high-pressure steam in a state where the paper layer 23 is in a corrugated shape (bellows shape), so that the paper layer 23 is likely to be raised. Further, as described above, since short fibers having a fiber length of 20 mm or less are used for the paper layer 23, the paper layer 23 is more likely to be raised. For this reason, as shown in FIG. 9, one end of the fiber in the paper layer 23 ejected with high-pressure steam protrudes from the surface of the paper layer 23, and raised paper 57 is generated in the paper layer 23. Since this raising 57 adheres dirt well, the nonwoven fabric can further remove dirt by this raising 57.

By adjusting the nozzle pitch of the nozzle holes 141 of the water vapor nozzle 14, the water vapor pressure of high-pressure water vapor, etc., the non-woven fabric is wiped in the machine direction ( MD) and the balance between the wiping performance of the nonwoven fabric when wiping dirt can be controlled. For example, when the nozzle pitch of the nozzle holes 141 of the water vapor nozzle 14 is reduced, when the nonwoven fabric is moved in the width direction (CD) of the nonwoven fabric to wipe off the dirt, the ability to wipe off the dirt in the nonwoven fabric can be further improved. When the nozzle pitch of the 14 nozzle holes 141 is increased, the ratio of the remaining portion of the crepe of the nonwoven fabric increases, so when the nonwoven fabric is moved in the machine direction (MD) of the nonwoven fabric and the stain is wiped off, the stain on the nonwoven fabric is wiped off. The ability to take can be further improved.

The suction force by which the suction drum 13 sucks the paper layer 23 by the suction device built in the suction drum 13 that sucks the steam ejected from the steam nozzle 14 is preferably −1 to −12 kPa. If the suction force of the suction drum 13 is less than −1 kPa, steam may not be sucked and blowing up may occur. Further, when the suction force of the suction drum 13 is larger than −12 kPa, there are cases where the fiber drops into the suction increase.

The distance between the tip of the steam nozzle 14 and the upper surface of the paper layer 23 is preferably 1.0 to 10 mm. If the distance between the tip of the steam nozzle 14 and the upper surface of the paper layer 23 is smaller than 1.0 mm, a hole may be formed in the paper layer 23, or the paper layer 23 may be torn or blown off. Further, if the distance between the tip of the steam nozzle 14 and the upper surface of the paper layer 23 is greater than 10 mm, the force for forming grooves on the surface of the paper layer 23 in high-pressure steam is dispersed, and the paper layer 23. In some cases, the efficiency of forming the groove on the surface of the film deteriorates.

The moisture content of the paper layer 23 after jetting high-pressure steam is preferably 35% or less, and more preferably 30% or less. If the moisture content of the paper layer 23 after jetting high-pressure steam is greater than 35%, it may be difficult to reduce the moisture content of the paper layer 23 to 5% or less by drying with a drying dryer described later. In this case, additional drying is required, and the production efficiency of the nonwoven fabric is deteriorated.

Thereafter, as shown in FIG. 1, the image is transferred to a dry dryer 22 different from the dry dryer 20. The drying dryer 22 dries the paper layer 23 sprayed with high-pressure steam until it becomes a nonwoven fabric as a final product. As the drying dryer 22, for example, a Yankee dryer is used. The drying dryer 22 attaches the paper layer 23 to the surface of the cylindrical dryer heated to about 150 ° C. by steam, and dries the paper layer 23.

The paper layer 23 after passing through the dry dryer 22 needs to be sufficiently dry. Specifically, the moisture content of the paper layer 23 after passing through the dry dryer 22 is preferably 5% or less. In addition, when the moisture content of the paper layer 23 immediately after jetting high-pressure steam is 5% or less, the paper layer 23 jetted with high-pressure steam does not have to be dried using the drying dryer 22 or the like.

The dried paper layer 23 (nonwoven fabric) is taken up by the winder 21.

A micrograph of the surface of the nonwoven fabric produced as described above is shown in FIG. This surface is a surface on which high-pressure steam is jetted. From FIG. 10, the manufactured nonwoven fabric has a groove part arranged in the machine direction (MD) and aligned in the width direction (CD) and a crepe extended in the width direction (CD) and arranged in the machine direction (MD). I understand.

In addition, when the step of forming the crepe is performed after jetting the high-pressure steam rather than before jetting the high-pressure steam, the groove formed by spraying the steam on the paper layer is destroyed in the step of forming the crepe, In some cases, the fibers may be loosened, causing troubles such as fiber loss and sheet tearing.

By cutting the nonwoven fabric produced as described above into a predetermined size, this nonwoven fabric can be used as a dry wipe. Moreover, this nonwoven fabric can be used as a wet wipe by cutting the nonwoven fabric produced as described above into a predetermined dimension and impregnating the nonwoven fabric with a predetermined amount of chemical solution into the fabric.

As described above, after the crepe 52 is formed on the paper layer 23, the groove 53 is formed on the paper layer 23 by high-pressure steam. Therefore, a process for producing a wipe from a nonwoven fabric, for example, a process for cutting the nonwoven fabric, The crepe of the nonwoven fabric is not lost in the impregnation step or the like. Therefore, the wipes produced from the nonwoven fabric according to one embodiment of the present invention can remove stains well regardless of the direction in which the wipes are wiped off.

The above description is merely an example, and the invention is not limited to the above embodiment.

Hereinafter, the present invention will be described in more detail based on examples. However, the present invention is not limited to these examples.

In Examples and Comparative Examples, moisture content of paper layer before steam spraying, basis weight of paper layer before crepe, basis weight of paper layer after crepe, dry thickness, density, dry tensile strength, dry tensile elongation, wet tensile strength, wet tensile elongation The soil removal rate on the high-pressure steam jet surface and the soil removal rate on the high-pressure water jet surface were measured as follows.

(Water content of paper layer before steam spraying)
A sample piece having a size of 30 cm × 30 cm was sampled from the paper layer dried by the dry dryer 20, and the weight (W1) of the sample piece was measured. Then, after leaving the sample piece to stand in a 105 degreeC thermostat for 1 hour and drying, the weight (D1) was measured. The moisture content of the paper layer before steam spraying is an average value of the measured values at N = 10.
Water content of paper layer before steam spraying = (W1-D1) / W1 × 100 (%)

(Crepe paper weight per crepe)
The basis weight of the paper layer was calculated by sampling a measurement sample having a size of 30 cm × 30 cm from the paper layer before forming the crepe dried by the dry dryer 20 and measuring the weight of the sampled measurement sample. The paper layer basis weight is an average value of measured values at N = 10.

(Weight per sheet after crepe)
The basis weight of the paper layer was calculated by sampling a measurement sample having a size of 30 cm × 30 cm from the paper layer before jetting the high-pressure water vapor that formed the crepe, and measuring the weight of the sampled measurement sample. The paper layer basis weight is an average value of measured values at N = 10.

(Dry thickness)
A sample for measurement having a size of 10 cm × 10 cm was sampled from the manufactured nonwoven fabric. Using a thickness gauge (model FS-60DS manufactured by Daiei Chemical Seiki Seisakusho Co., Ltd.) equipped with a 15 cm ² probe, measure the thickness of the sample for measurement under the measurement conditions of 3 gf / cm ² did. Three thicknesses were measured for one measurement sample, and the average value of the three thicknesses was defined as the dry thickness.

(density)
A sample for measurement having a size of 10 cm × 10 cm was sampled from the manufactured nonwoven fabric. The weight of the measurement sample was measured, and the density of the nonwoven fabric was calculated from the dry thickness.

(Dry tensile strength)
For measurement, a strip-shaped test piece with a width of 25 mm whose longitudinal direction is the machine direction of the paper layer and a strip-shaped test piece with a width of 25 mm whose longitudinal direction is the width direction of the paper layer are cut from the manufactured nonwoven fabric. A sample was prepared. Samples for measurement in the machine direction and width direction were each for three measurements using a tensile tester (manufactured by Shimadzu Corporation, Autograph Model AGS-1kNG) equipped with a load cell with a maximum load capacity of 50N. For the sample, the tensile strength was measured under the conditions of a distance between grips of 100 mm and a tensile speed of 100 mm / min. The average value of the tensile strengths of the three measurement samples of the measurement sample in the machine direction and the width direction was taken as the dry tensile strength in the machine direction and the width direction.

(Dry tensile elongation)
For measurement, a strip-shaped test piece with a width of 25 mm whose longitudinal direction is the machine direction of the paper layer and a strip-shaped test piece with a width of 25 mm whose longitudinal direction is the width direction of the paper layer are cut from the manufactured nonwoven fabric. A sample was prepared. Samples for measurement in the machine direction and width direction were each for three measurements using a tensile tester (manufactured by Shimadzu Corporation, Autograph Model AGS-1kNG) equipped with a load cell with a maximum load capacity of 50N. The sample was measured for tensile elongation under the conditions of a distance between grips of 100 mm and a tensile speed of 100 mm / min. Here, the tensile elongation is a value obtained by dividing the maximum elongation (mm) when the measurement sample is pulled by a tensile tester by the distance between grips (100 mm). The average value of the tensile elongation of each of the three measurement samples of the measurement sample in the machine direction and the width direction was defined as the dry tensile elongation in the machine direction and the width direction.

(Wet tensile strength)
A 25 mm wide strip-shaped test piece whose longitudinal direction is the machine direction of the paper layer and a 25 mm wide strip-shaped test piece whose longitudinal direction is the width direction of the paper layer are cut out from the manufactured nonwoven fabric, and a measurement sample Was prepared, and the measurement sample was impregnated with water 2.5 times the mass of the measurement sample (water content magnification: 250%). Then, using the tensile tester (manufactured by Shimadzu Corp., Autograph Model AGS-1kNG), each of three samples for measurement in the machine direction and the width direction were equipped with a load cell with a maximum load capacity of 50N. For the measurement sample, the tensile strength was measured under the conditions of a distance between grips of 100 mm and a tensile speed of 100 mm / min. The average value of the tensile strength of each of the three measurement samples of the measurement sample in the machine direction and the width direction was defined as the wet tensile strength in the machine direction and the width direction.

(Wet tensile elongation)
A 25 mm wide strip-shaped test piece whose longitudinal direction is the machine direction of the paper layer and a 25 mm wide strip-shaped test piece whose longitudinal direction is the width direction of the paper layer are cut out from the manufactured nonwoven fabric, and a measurement sample Was prepared, and the measurement sample was impregnated with water 2.5 times the mass of the measurement sample (water content magnification: 250%). And, using the tensile tester (manufactured by Shimadzu Corp., Autograph model AGS-1kNG), each of the three samples for measurement in the machine direction and width direction was equipped with a load cell with a maximum load capacity of 50N. For the measurement sample, the tensile elongation was measured under the conditions of a distance between grips of 100 mm and a tensile speed of 100 mm / min. The average value of the tensile elongation of each of the three measurement samples of the measurement sample in the machine direction and the width direction was defined as the wet tensile elongation in the machine direction and the width direction.

(Dirt removal rate on the high-pressure steam injection surface)
The soil removal rate on the surface of the nonwoven fabric on which high-pressure water vapor was jetted (high-pressure water vapor jet surface) was measured by the following procedure.
(1) 12.6% by weight of carbon black (Carbon Black, manufactured by Yoneyama Pharmaceutical Co., Ltd.), 20.8% by weight of beef tallow extremely hardened oil (manufactured by Nippon Oil & Fats Co., Ltd.) and 66.6% by weight of fluid A simulated soil paste containing paraffin (manufactured by Nacalai Tesque) was prepared. The simulated soil paste was diluted with hexane so that the soil paste: hexane (manufactured by Nacalai Tesque Co., Ltd.) was in a weight ratio of 85:15 to prepare a simulated soil agent.
(2) 0.05 ml of the simulated soiling agent was dropped on the prepared slide, and the prepared slide where the simulated soiling agent was dropped was dried in an atmosphere of a temperature of 20 ° C. and a humidity of 60% for 24 hours.
(3) After drying, using a scanner (Calario GT-750, manufactured by Epson), document type: film, type: positive film, image: 16-bit gray, quality: image quality priority, resolution: 1200 dpi, document size: 68 .6 × 237 mm, output: The image of the slide is captured under the same magnification condition. From the image data of the captured image, the range of 16.9 mm × 16.9 mm in the portion where the simulated stain of the slide is attached The color was calculated. Here, the color was calculated as follows. An image captured by tone correction with a predetermined threshold value set was converted to two gradations. The threshold value for making two gradations was set so that the gradation of the part where the dirt was attached was 0 (black) and the gradation of the part where the dirt was not attached was 255 (white). Then, using Excel 2007 (manufactured by Microsoft), a histogram in which the horizontal axis is gradation and the vertical axis is frequency is created. The frequency of 0 gradation was used as the color.
(4) Wiping of the simulated soiling agent adhering to the preparation with the nonwoven fabric was performed by applying a plastic film- and sheet-friction coefficient test method (JIS-K-7125: 1999). A sample for measurement having a size of 140 × 190 mm was sampled from the manufactured nonwoven fabric, and the sample for measurement was attached to the table of a friction coefficient measuring device (manufactured by Tester Sangyo Co., Ltd.) so that the high-pressure steam spraying surface was on top. At this time, the measurement sample was arranged so that the moving direction of the sliding piece was the direction in which the measurement sample was wiped off (machine direction (MD) or width direction (CD)). After placing the preparation with the simulated soiling agent on the measurement sample so that the surface with the simulated soiling agent contacts the measurement sample, the surface opposite to the surface of the preparation with the simulated soiling material attached Sliding pieces and load cells were attached to the. Then, the coefficient of friction measurement was performed once under the conditions of a feed rate of 150 mm / min and a load of 60 g, thereby wiping the simulated stain adhering to the preparation with the measurement sample.
(5) After wiping off the simulated stain adhering to the slide, the image of the slide is captured under the same conditions using the scanner described above, and the color in the slide before the simulated stain is wiped from the image data of the captured image. The same range of color as the range in which the taste was calculated was calculated.
(6) Subtract the color after wiping off the simulated stain adhering to the slide from the color before wiping off the simulated stain adhering to the slide, and the color before wiping off the simulated stain attached to the slide. The color change rate was calculated by dividing the value. This value was defined as the dirt removal rate of the measurement sample. If the measurement sample has good wiping properties, the simulated stain adhering to the preparation is wiped clean by the measurement sample, so that the color change rate, that is, the stain removal rate increases. On the other hand, if the wiping property of the measurement sample is poor, a lot of the simulated stain remains in the slide where the simulated stain is wiped off by the measurement sample, so that the color change rate, that is, the stain removal rate becomes small. Thus, the ability to wipe off the dirt of the measurement sample can be evaluated by the value of the dirt removal rate. The soil removal rate was measured for three measurement samples, and the average value was taken as the soil removal rate of the measurement sample.

(Dirt removal rate on high-pressure water jet surface)
The high pressure water jet surface is the same as the dirt removal rate on the high pressure steam jet surface, except that the measurement sample is mounted on the friction coefficient measuring device table so that the high pressure water jet surface (the surface on which the high pressure water flow is jetted) is up. The soil removal rate was measured.

Hereinafter, production methods of Examples and Comparative Examples will be described.

Example 1
Example 1 was produced using the nonwoven fabric manufacturing apparatus 1 in one embodiment of the present invention. A papermaking raw material containing 70% by weight of softwood bleached kraft pulp (NBKP) and 30% by weight of rayon (Corona, manufactured by Daiwabo Rayon Co., Ltd.) having a fineness of 1.1 dtex and a fiber length of 7 mm was prepared. . And the papermaking raw material was supplied on the paper layer formation belt (Nippon Filcon Co., Ltd. OS80) using the raw material head, and the papermaking raw material was spin-dry | dehydrated using the suction box, and the paper layer was formed. The paper layer moisture content of the paper layer at this time was 80%. Thereafter, a high pressure water stream was jetted onto the paper layer using two high pressure water stream nozzles. The high-pressure water energy of the high-pressure water jet sprayed onto the paper layer using two high-pressure water nozzles was 0.2846 kW / m ² . Here, the high-pressure water flow energy is calculated from the following equation.
High-pressure water flow energy (kW / m ² ) = 1.63 x injection pressure (kg / cm ² ) x injection flow rate (m ³ / min) / treatment speed (M / min) / 60
Here, injection flow rate (cubic M / min) = 750 × total orifice opening area (m ² ) × injection pressure (kg / cm ² ) ^0.495

The distance between the tip of the high-pressure water flow nozzle and the top surface of the paper layer was 10 mm. Furthermore, the hole diameter of the nozzle holes of the high-pressure water flow nozzle was 92 μm, and the hole pitch of the nozzle holes was 0.5 mm.

The paper layer was transferred to two paper layer conveyors, and then transferred to a Yankee dryer heated to 160 ° C. and dried. The line speed in this Yankee dryer was 80 m / min. And the crepe process was implemented by separating the paper layer adhering to the surface of a Yankee dryer from the surface through a doctor blade, and the crepe was formed in the paper layer. The line speed of the Yankee dryer that dries the paper layer sprayed with high-pressure steam described later was 68 m / min. Due to the difference in line speed between the two Yankee dryers, the crepe rate of the formed crepe could be 14%.

Next, using one steam nozzle, high-pressure steam was jetted onto the surface of the paper layer opposite to the surface on which the high-pressure water flow was jetted (the side opposite to the high-pressure water jet surface). The vapor pressure of the high-pressure steam at this time was 0.7 MPa, and the vapor temperature was 210 ° C. The distance between the tip of the steam nozzle and the upper surface of the paper layer was 2.0 mm. The nozzle holes of the steam nozzles were arranged in three rows in the machine direction (MD). Furthermore, the hole diameter of the nozzle hole of the steam nozzle was 500 μm, and the hole pitch was 4.0 mm. Further, the suction force with which the suction drum sucked the paper layer was −5 kPa. A stainless steel 18 mesh perforated sleeve was used on the outer periphery of the suction drum.

The paper layer was transferred to a Yankee dryer heated to 150 ° C. and dried. The dried paper layer is Example 1.

(Comparative Example 1)
Comparative Example 1 was produced by a method similar to that of Example 1 except that the high-pressure water stream was not jetted onto the paper layer.

(Comparative Example 2)
The comparative example 2 was manufactured by the method similar to the manufacturing method of Example 1 except the point which did not implement the process which forms a crepe.

(Comparative Example 3)
Example 3 was produced by a method similar to that of Example 1 except that high-pressure steam was not jetted.

Table 1 shows the production conditions of the above examples and comparative examples.

Water content of paper layer before steam spraying, basis weight of paper layer before crepe, basis weight of paper layer after crepe, dry thickness, density, dry tensile strength, dry tensile elongation, wet tensile strength and wet in the above examples and comparative examples Table 2 shows the tensile elongation.

Table 3 shows the dirt removal rate on the high-pressure steam jet surface and the dirt removal rate on the high-pressure water jet surface in the above Examples and Comparative Examples.

(1) Comparison between Example 1 and Comparative Example 1 Since the strength of Comparative Example 1 was weak, in Comparative Example 1, it was possible to measure the dirt removal rate on the high-pressure steam injection surface and the dirt removal rate on the high-pressure water jet surface. There wasn't. In Comparative Example 1, the dry tensile strength and the wet tensile strength were very low. On the other hand, in Example 1, the dry tensile strength and the wet tensile strength were high, and it was possible to measure the soil removal rate on the high-pressure steam jet surface and the soil removal rate on the high-pressure water jet surface. From these, it was found that the strength of the nonwoven fabric can be increased by carrying out the step of jetting a high-pressure water stream onto the paper layer.

(2) Comparison between Example 1 and Comparative Example 2 In Comparative Example 2, the dry thickness was small and the density was high. In Comparative Example 2, the stain removal rate in the width direction (CD) of the nonwoven fabric was large, but the stain removal rate in the machine direction (MD) of the nonwoven fabric was small. On the other hand, in Examples 1 and 2, the dry thickness was large and the density was low. In Comparative Example 1, the dirt removal rate was large not only in the width direction (CD) but also in the machine direction (MD). From these, by carrying out the step of forming a crepe, the bulk of the nonwoven fabric can be increased, and the wiping property of dirt can be improved not only in the width direction (CD) but also in the machine direction (MD) of the nonwoven fabric. all right.

(3) Comparison between Example 1 and Comparative Example 3 In Comparative Example 3, the dry thickness was small and the density was high. Moreover, in the comparative example 3, the stain | pollution | contamination removal rate was small in the width direction (CD) and machine direction (MD) of a nonwoven fabric. On the other hand, in Example 1, the dry thickness was large and the density was low. In Examples 1 and 2, the dirt removal rate was large in the width direction (CD) and the machine direction (MD). Even if it implements the process of forming a crepe in a paper layer from these, unless it carries out the process of injecting high-pressure water vapor to a paper layer, it cannot improve the dirt wiping property of the machine direction (MD) of a nonwoven fabric. I understood. Further, it was found that by carrying out the step of injecting high-pressure steam onto the paper layer, the bulk of the nonwoven fabric can be increased and the wipeability of the nonwoven fabric in the width direction (CD) can be improved.

DESCRIPTION OF SYMBOLS 1 Nonwoven fabric manufacturing apparatus 11 Raw material supply head 12 High-pressure water flow nozzle 13 Suction drum 14 Steam nozzle 15 Suction box 16 Paper layer forming conveyor 17

Suction pickup

18, 19 Paper

layer conveying conveyor

20, 22 Drying dryer 21 Winder 23 Paper layer 26 Doctor Blade 31 High-pressure water flow 32 Recess 41 Paper layer forming belt 51 High-pressure steam 52 Crepe 53 Groove 57 Raised

Claims

Supplying a papermaking raw material containing moisture onto a belt moving in one direction, and forming a paper layer on the belt;
Injecting a high-pressure water stream onto the paper layer, extending in the machine direction, and forming recesses on the surface intermittently aligned in the width direction;
Drying the paper layer sprayed with the high-pressure water stream to a moisture content of 10 to 45% by attaching the paper layer sprayed with the high-pressure water stream to the surface of a rotating cylindrical dryer;
Forming a crepe on the paper layer by pulling the paper layer attached to the surface of the cylindrical dryer away from the surface via a doctor blade;
By injecting high-pressure steam from the steam nozzle onto the paper layer on which the crepe is formed, a groove portion having a width larger than the width of the recess and extending in the machine direction is left while leaving the crepe formed in the paper layer. Forming a nonwoven fabric on the surface of the layer.
The method for producing a nonwoven fabric according to claim 1, wherein the nozzle pitch of the nozzle holes of the steam nozzle is 3.0 to 7.0 mm.
The said steam nozzle is a manufacturing method of the nonwoven fabric of Claim 1 or 2 provided with two or more nozzle hole rows of the nozzle hole located in a line in the machine direction.
A longitudinal direction, a transverse direction intersecting the longitudinal direction, a thickness direction perpendicular to the longitudinal direction and the transverse direction, one surface perpendicular to the thickness direction, and the one side The other surface facing the surface in the thickness direction,
A groove extending in the longitudinal direction and arranged in the lateral direction on the one surface;
A nonwoven fabric having crepes extending in the lateral direction and arranged in the longitudinal direction on the one surface and the other surface.
The nonwoven fabric according to claim 4, wherein the crepe is provided between the adjacent groove portions.
The fiber length of the fiber contained in the said nonwoven fabric is 20 mm or less, The said nonwoven fabric is raising, The nonwoven fabric of Claim 4 or 5.