TWI588314B - Wet tissue with non-woven and its manufacturing method, and wet tissue - Google Patents

Description

Non-woven fabric for wet tissue and its manufacturing method, and wet tissue

The present invention relates to a nonwoven fabric for wet tissue.

(Patent Document 1) It is known that a layer having hydrophobic/hydrophilic properties of fibers is formed in the cross-sectional direction of the nonwoven fabric, and moisture is provided in the intermediate layer to improve the stability of the take-out, and it is less likely to ooze an appropriate amount of water during wiping. A wet tissue laminator that wipes moisture on the object.

[prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent No. 3138818

However, in the invention of Patent Document 1, due to the characteristics of the wet tissue, if the hydrophobicity level of the lifting layer causes the sheets to slide against each other and hinders the wiping action, the hydrophobicity and the level of water immersion between the layers cannot be clearly defined, and the formation cannot be formed. Defining the structure of the accumulated water. Further, since the method for fixing the interlayers uses the physical energy formed by the water needle method or the like to form a fiber entanglement, the layers are not clear and it is difficult to see the layer structure. Moreover, the layers are not clearly visible visually. In addition, there is a problem that it is impossible to reliably wipe with sufficient water and there is little residual state after wiping.

The present invention relates to a non-woven fabric for wet tissue, which is a non-woven fabric for wet tissue containing absorbent fibers, characterized in that at least one side of the non-woven fabric is formed with a plurality of first mu hills and first grooves extending in the same direction. The second acre and the second trench, the top height of the first acre is higher than the top of the second acre, and the height of the top of the second acre is higher than the height of the bottom of the second trench, the second trench The height of the bottom of the groove is higher than the height of the bottom of the first groove, the first groove is located between the two adjacent first mu hills, and the plurality of second acres and the second groove are located in the first absence Between the two first acres adjacent to the groove and adjacent, the interval between the two first acres adjacent to each other through the first groove is two adjacent to the second groove The interval between the acres is wider.

Preferably, the apparent density of the non-woven dry state of the first acre and the first groove is smaller than the apparent density of the dry state of the second acre and the second groove.

Preferably, the difference between the top height of the first acre and the top height of the second acre is 0.1 mm or more.

Preferably, the absorbent fiber system comprises cellulose.

Preferably, the non-woven fabric can visually confirm the liquid holding portion and the non-holding portion when the liquid is impregnated.

It is preferable that 30% or more of the fibers constituting the nonwoven fabric are absorbent fibers.

Preferably, the apparent density of the non-woven dry state of the first acre and the first groove is 0.30 to 0.10 g/cm ³ , and the apparent density of the non-woven dry state of the second acre and the second groove is It is 0.12~0.20g/cm ³ .

Preferably, the interval between the two first acres adjacent to each other via the second acre and the second groove is 3 mm or more.

Preferably, the fiber constituting the nonwoven fabric has a fiber length of 20 mm or less.

Preferably, the difference between the height of the top of the second acre and the height of the bottom of the second groove is 0.05 to 0.10 mm.

Preferably, the interval between the two second acres adjacent to each other across the second groove is 0.3 to 1.0 mm.

Preferably, the difference between the height of the top of the first acre and the height of the bottom of the first groove is 0.15 to 0.60 mm.

Preferably, in the absence of the second acre and the second trench and between the two adjacent first mu hills, a third acre is further formed, and the top height of the third acre is higher than the second acre The top is higher in height.

Preferably, the first acre and the first groove are formed by steam injection, and the second acre and the second groove are formed by water jet.

The present invention is another method for producing the above-mentioned non-woven fabric for wet tissue, comprising: a step of supplying a mixture of fibers and water containing absorbent fibers to a support, and forming a water-containing belt on the support; a water flow nozzle in which the water flow nozzles arranged at equal intervals in the width direction of the belt body sprays the belt body to entangle the fibers; and the water vapor nozzles arranged at a larger interval from the water flow nozzles in the width direction of the belt body, a step of performing steam injection on the belt after the water jet is sprayed; The step of drying the belt after the steam is sprayed.

The present invention is a wet tissue made by impregnating the aforementioned nonwoven fabric with a liquid.

The non-woven fabric for wet tissue of the present invention can have a thick acre and a groove (the first acre and the first groove) and a fine acre and a groove (the second acre and the second groove) The coarse grooves entangle the larger dirt and the smaller grooves entangle the smaller dirt. In other words, the present invention is capable of removing coarse dirt and fine dirt at a time with a single sheet.

Hereinafter, the present invention will be described with reference to the drawings, but the present invention is not limited by the contents described in the drawings.

Fig. 1 is a schematic enlarged perspective view of the nonwoven fabric of the present invention.

The non-woven fabric 1 of the present invention has a plurality of first acre 3, a first groove 4, a second acre 5, and a second groove 6 extending in the same direction Y on at least one surface. Top of the first height h of 3T mu mound height h _{5 3} higher than the top of the mound of second acres of 5T, 5T top of the second mu mound height h than the height h ₅ of the bottom of the second trench 6B more ₆ High, the height h ₆ of the bottom 6B of the second trench is higher than the height h ₄ of the bottom 4B of the first trench. Here, the height means a height perpendicular to the direction of the one surface from the opposite surface of the one surface. Further, in the case where the opposite surface has an acre and a groove, the heights h ₃ , h ₄ , h ₅ , and h ₆ refer to the height from the top of the most prominent acre of the opposite surface. The first groove 4 is located between two adjacent first acre hills 3, 3. The plurality of second acre hills 5 and the second trench 6 are located between the two first acre hills 3, 3 where the first trench 4 is not present and adjacent. The interval d ₃ between the two first acres 3, 3 adjacent to each other across the first groove 4 is wider than the interval d ₅ between the two second acres adjacent to each other via the second groove.

In other words, the non-woven fabric of the present invention is on at least one side, having a thick mound and groove (the first acre and the first groove) and a fine acre and a groove (the second acre and the second groove) ). It is possible to entangle larger dirt with thicker grooves and to entangle smaller dirt with fine grooves. In other words, the present invention is capable of removing coarse dirt and fine dirt at a time with a single sheet.

The difference between the top height h _{3 of the} first acre and the top height h ₅ of the second acre (h ₃ -h ₅ ) is preferably 0.1 mm or more, more preferably 0.12 to 0.70 mm, and particularly preferably 0.15 to 0.50. Mm. When the difference (h ₃ -h ₅ ) is too small, the scraping property of the dirt is deteriorated, and it is not easy to be bulky. On the contrary, when the amount is too large, damage to the sheet is large and the sheet strength is lowered, and the fiber is easily lost.

The interval d ₃ between the two first acres 3 and 3 adjacent to the second acre 5 and the second groove 6 is preferably 3 mm or more, more preferably 4.0 to 8.0 mm, and particularly preferably 4.5 to 4.5 6.0mm. When the interval d _{3 is} too small, it is difficult to form the second acre and the region R ₂ where the second groove is located. On the other hand, when the interval d _{3 is} too large, the number of the acre and the groove is reduced, the scraping property of the dirt is deteriorated, and the bulkiness is not easily maintained.

The difference between the top height h _{5 of the} second acre and the bottom height h ₆ of the second groove (h ₅ -h ₆ ) is preferably 0.05 to 0.10 mm, more preferably 0.06 to 0.09 mm, and particularly preferably 0.07. 0.08mm. When the difference (h ₅ -h ₆ ) is too small, it becomes a paper-like feeling and becomes hard. Conversely, when the difference (h ₅ -h ₆ ) is too large, the contact area becomes small and the wiping effect is deteriorated. Further, the heights h ₃ , h ₄ , h ₅ , and h ₆ can be obtained from a microscopic photograph of the cross section.

The interval d ₅ between the two second acres 5 and 5 adjacent to each other via the second groove 6 is preferably 0.3 to 1.0 mm, more preferably 0.4 to 0.8 mm, and particularly preferably 0.5 to 0.7 mm. When the interval d _{5 is} too small, it is difficult to form irregularities, and when the distance is too large, a weak portion of the fiber entanglement occurs, and the sheet strength is not uniform.

The difference between the top height h _{3 of the} first acre and the bottom height h ₄ of the first groove (h ₃ -h ₄ ) is preferably 0.15 to 0.60 mm, more preferably 0.17 to 0.55 mm, and particularly preferably 0.20. 0.50mm. When the difference (h ₃ -h ₄ ) is too small, the effect of entanglement of the dirt becomes low, and when it is too large, it is difficult to maintain the shape of the shape or increase the amount of fiber loss.

In a first venturi and Area mu aspect of the present invention a first groove R of the apparent density of the nonwoven fabric ₁ in a dry state, and the second ratio of the second venturi mu trench Area ₂ of the dry R The apparent density is smaller.

A first trench and a first venturi mu Area of R ₁ non-woven fabric apparent density in the dry state, preferably 0.030 ~ 0.10g / cm ^3, more preferably 0.04 ~ 0.09g / cm ^3, particularly preferably 0.05 to 0.08 g/cm ³ . When the apparent density of the region R ₁ is too small, the number of fibers in the convex portion is too small to collapse, and when the amount is too large, the number of fibers is too large, and the dirt is less likely to enter the wiping property.

The apparent density of the non-woven dry state of the region R ₂ of the second acre and the second groove is preferably 0.12 to 0.20 g/cm ³ , more preferably 0.13 to 0.19 g/cm ³ , and particularly preferably 0.14 to 0.18. g/cm ³ . When the apparent density of the region R ₂ is too small, the contact area becomes small and becomes rough after wiping, and it is not suitable for the wiping. On the contrary, when it is too large, it tends to become a paper-like feeling, and the touch is easily hardened.

In the non-woven fabric of the preferred aspect of the present invention, since the region R ₂ having a large apparent density and the region R ₁ having a small apparent density are present, when the liquid is impregnated, the liquid is largely concentrated in the region R ₂ having a large apparent density, and the liquid is not It exists too much in the region R ₁ where the apparent density is small. In other words, in the nonwoven fabric of the preferred aspect of the present invention, the liquid holding portion and the non-holding portion can be visually confirmed when the liquid is impregnated. The liquid may, for example, be a mixed solution of a preservative such as distilled water, propylene glycol or paraben. If the liquid is, for example, water, the density of the water concentrates the water between the fibers in the small acre part, and the large acre part is in a state of no water, so that the water from the small acre part is floated when the object is wiped. The water is taken up by the large acre part so that the dirt can be wiped off without leaving moisture on the surface of the wiping object.

The first acre 3 and the first groove 4 may be formed by steam injection, and the second acre 5 and the second groove 6 may be formed by water jet injection, which will be described later in detail.

A schematic enlarged cross-sectional view of a non-woven fabric of another aspect of the present invention is shown in Fig. 2. In the non-woven fabric shown in Fig. 2, there is no second acre hill 5 and the second acre 5 and the adjacent first two acre hills 3 and 3, and a third acre hill 7 is further formed. In the aspect shown in FIG. 2, two third acre hills 7 are formed between the adjacent two first acre hills 3 and 3, and one or more may be one or more. Where there are two or more third acres 7 formed between two adjacent first mu hills 3 and 3, there is a third groove between two adjacent third acre hills 7 8. The height h ₇ of the top 7T of the third acre ₇ is higher than the height h 5 of the top 5T of the second acre ₅ . 7 the top of the third venturi mu 7T height h of the lines ₇ may be the same or different from the first height h 3 mu mound top ₃ of 3T. Top of the third line is preferably the same as the height of 7 mu venturi h 7T ₇ and the top of the first 3 mu mound height h 3T _3. The height h ₈ of the bottom portion 8B of the third trench 8 may be the same as or different from the height h ₄ of the bottom portion 4B of the first trench 4. Preferably, the height h ₈ of the bottom portion 8B of the third trench 8 is the same as the height h ₄ of the bottom portion 4B of the first trench 4.

The nonwoven fabric of the present invention comprises absorbent fibers.

It is preferable that 30% or more of the fibers constituting the nonwoven fabric are absorbent fibers, more preferably 35% or more are absorbent fibers, and particularly preferably 40% or more are absorbent fibers. The fibers constituting the non-woven fabric may all be absorbent fibers.

The absorbent fibers which can be used in the present invention include wood pulp such as chemical pulp of conifer or hardwood, semi-chemical pulp and mechanical pulp, mercerized pulp and bridging pulp which are chemically treated. It is a non-wood fiber such as a cotton fiber, a cellulose fiber such as a regenerated fiber such as a ray fiber, or a polyvinyl alcohol fiber.

The absorbent fiber preferably contains cellulose.

Examples of the fibers other than the absorbent fibers include synthetic fibers such as polyethylene fibers, polypropylene fibers, polyester fibers, and polyamide fibers.

The fiber length of the fiber constituting the nonwoven fabric is preferably 20 mm or less, more preferably 1 to 15 mm, and particularly preferably 2 to 12 mm. When the fiber length is too long, it is not easily dispersed uniformly in water, and the texture is liable to be deteriorated. On the other hand, when the fiber length is too short, the processing yield at the time of papermaking is deteriorated, and the water flow entanglement becomes difficult and the strength is liable to become low.

The nonwoven fabric of the present invention can be produced by a method comprising the following steps: a step of supplying a mixture of fibers and water containing absorbent fibers to a support to form an aqueous belt on the support; and arranging at equal intervals along the width direction of the belt (direction perpendicular to the traveling direction of the belt) The water flow nozzle sprays the belt body to entangle the fibers; the water vapor nozzles arranged at a greater interval from the water flow nozzle in the width direction of the belt body, and the water vapor of the belt after the water jet is sprayed a step of spraying; and a step of drying the strip after the steam is sprayed.

Hereinafter, a method of producing the nonwoven fabric of the present invention will be described in detail.

Fig. 3 is a view showing an example of a nonwoven fabric manufacturing apparatus for producing the nonwoven fabric of the present invention.

First, a mixture of the fibers containing the absorbent fibers and water is supplied to the support of the belt forming conveyor 16 via the raw material supply head 11, and is deposited on the support. The support preferably has a gas permeability that is permeable to water vapor. For example, a metal mesh, a felt, or the like can be used as the support.

The water-containing fibers deposited on the support are appropriately dehydrated by the suction box 13 to form the belt 30. The belt body 30 passes through two water flow nozzles 12 disposed on the support body, and two suction boxes disposed at positions facing the water flow nozzle 12 via the support body and recovering water sprayed from the water flow nozzle 12 Between 13 At this time, the belt body 30 is sprayed by the high-pressure water stream from the water flow nozzle 12, and the second acre and the second groove are formed in the belt body 30.

One of the water flow nozzles 12 is illustrated in Fig. 4. Water flow nozzle 12 will A plurality of water streams 31 arranged in the width direction (CD) of the belt body 30 are ejected toward the belt body 30. As a result, a plurality of grooves 32 that are arranged in the width direction of the belt body 30 and extend in the machine direction (MD) are formed on the belt body 30. The groove 32 corresponds to the second groove 6.

Further, when the belt body 30 is subjected to the water flow, the grooves 32 are formed in the belt body 30 as described above and the fibers of the belt body 30 are entangled with each other, and the strength of the belt body 30 becomes high. The principle in which the fibers of the belt 30 are entangled with each other when the belt body 30 is subjected to a water flow will be described with reference to Fig. 5, but this principle is not intended to limit the present invention.

As shown in Fig. 5, when the water flow nozzle 12 ejects the water flow 31, the water flow 31 passes through the support 41. The fibers of the belt 30 thereby carry the water stream 31 through the portion 42 of the support 41 to the center. As a result, the fibers of the belt 30 are gathered toward the water stream 31 through the portion 42 of the support 41 to entangle the fibers with each other.

The fibers of the belt body 30 are entangled with each other to increase the strength of the belt body 30, whereby in the subsequent step, even if water vapor is sprayed on the belt body 30, the opening, the cracking, and the blow-off are reduced. Further, the wetting strength of the belt body 30 can be increased without adding a paper strength enhancer to the raw material.

The water jetted from the water jet nozzle 12 is a high pressure water stream.

The energy of the water flow when the water stream is sprayed on the belt body 30 is preferably 0.125 to 1.324 kW/m ² .

The energy of the water flow is calculated by the following formula.

Energy of water flow (kW/m ² ) = 1.63 × injection pressure (Kg / cm ² ) × injection flow rate (m ³ /min) / treatment time (m / min) / 60

Here, the injection flow rate (m ³ /min) = 750 × total opening area of the orifice (m ² ) × injection pressure (Kg / cm ² ) 0.495

When the energy of the water flow is less than 0.125 kW/m ² , the strength of the belt 30 may not be strong enough. Further, when the energy of the water flow is more than 1.324 kW/m ² , the belt body 30 becomes too hard, and the volume of the belt body 30 does not become large by the high-pressure steam which will be described later.

The distance between the front end of the water flow nozzle 12 and the upper surface of the belt body 30 is preferably 5.0 to 20.0 mm. When the distance between the tip end of the water flow nozzle 12 and the upper surface of the belt body 30 is less than 5.0 mm, the water potential due to the high-pressure water flow is likely to be disturbed, and the fiber rebounded due to the water potential of the water flow is likely to adhere to the fiber. The situation with such problems as nozzles. Further, when the distance between the tip end of the water flow nozzle 12 and the upper surface of the belt body 30 is larger than 20.0 mm, the treatment efficiency is remarkably lowered, and there is a problem that the fiber entanglement becomes weak.

The diameter of the water jet nozzle 12 is preferably from 90 to 150 μm. When the pore diameter of the water flow nozzle 12 is too small, there may be a problem that the nozzle is easily clogged. Further, when the diameter of the water flow nozzle 12 is too large, there may be a problem such as a deterioration in processing efficiency.

The pitch of the holes of the water jet nozzle 12 (the distance between the centers of the adjacent holes) is preferably 0.3 to 1.0 mm. When the hole pitch of the water flow nozzle 12 is too small, there is a problem that the pressure resistance of the nozzle is lowered or broken. Further, when the hole pitch of the water flow nozzle 12 is too large, there may be a problem such as insufficient fiber entanglement.

The strip 30 passing between the two water jet nozzles 12 and the two suction boxes 13 is shown in Fig. 6 as a cross section in the width direction. By high pressure water flow A second acre and a second groove are formed on the upper surface of the belt body 30. According to the conditions of the water jet, an acre and a groove (not shown) are formed in the same manner on the opposite surface of the water jet surface.

Next, the belt body 30 passes through two water vapor nozzles 14 disposed on the support body and disposed at a position opposed to the steam nozzle 14 via the support body, and sucks water sprayed from the water vapor nozzle 14. The two vapor boxes are between the suction boxes 13. At this time, the belt body 30 is sprayed with water vapor from the steam nozzle 14, and the first acre 3 and the first groove 4 are formed on the upper surface (the surface on the side of the steam nozzle 14). In the case of using the non-woven fabric manufacturing apparatus shown in Fig. 3, the surface of the belt to which the water vapor is sprayed is the same as the surface on which the water jet is sprayed. According to the conditions of the water jet, the acre and the groove are formed on the opposite side of the water jet surface, but in the case where the mucus and the groove are formed on the opposite side of the water jet surface, the device can also be modified in the water jet surface. The opposite side of the water vapor spray.

One of the steam nozzles 14 is illustrated in Fig. 7. The steam nozzle 14 sprays a plurality of water vapors 51 arranged in the width direction (CD) of the belt body 30 toward the belt body 30. As a result, on the upper surface of the belt body 30, a plurality of grooves 52 which are arranged in the width direction of the belt body 30 and extend in the machine direction (MD) are formed. The groove 52 corresponds to the first groove 4.

The principle of forming the first acre 3 and the first groove 4 when the belt 30 is sprayed with water vapor will be described with reference to Fig. 8, but this principle is not intended to limit the present invention.

As shown in Fig. 8, when the steam nozzle 14 sprays the water vapor 51, the water vapor 51 comes into contact with the support 41. Water vapor 51 and nozzle from water flow The 12 jets of water 31 are different, and most of them are bounced back by the support body 41. Thereby the fibers of the belt 30 are rolled up and then released. In addition, the fibers of the belt body 30 passing through the water vapor 51 are disengaged, and the first groove 4 is formed, and the fibers that have been plucked are moved toward the width direction side of the portion 53 where the water vapor 51 contacts the support body 41, and are gathered to form the first One acre of hills 3.

Since the strength of the high-pressure water stream belt 30 is improved, when the water vapor 51 is sprayed on the belt body 30, it is not necessary to provide a net for preventing the belt body 30 from being sprayed by the water vapor 51 on the belt body 30. Therefore, the treatment efficiency of treating the belt body 30 with the water vapor 51 is improved. Further, since it is not necessary to provide the above-described net, it is possible to reduce the maintenance cost of the nonwoven fabric manufacturing apparatus 10 and the manufacturing cost of the nonwoven fabric.

The water vapor sprayed from the steam nozzle 14 is high pressure water vapor. The pressure of the water vapor sprayed from the steam nozzle 14 is preferably 0.3 to 1.5 MPa. When the pressure of the water vapor is less than 0.3 MPa, there may be a case where the first acre of a sufficient height is not formed. Further, when the steam pressure of the high-pressure steam is more than 1.5 MPa, the opening of the belt 30 may occur, or the belt 30 may be broken and blown.

By the suction box 13 for sucking the water vapor sprayed from the steam nozzle 14, the suction force of the support for attracting the belt is preferably -1 to -12 kPa. When the suction force of the support is less than -1 kPa, there is a problem that the problem that the water vapor is not exhausted and the spray is generated may occur. In addition, when the attraction force of the support is more than -12 kPa, there may be such a problem that the amount of fibers falling off into the suction becomes large.

The distance between the front end of the water vapor nozzle 14 and the upper surface of the belt body 30 is higher. Good is 1.0~10mm. When the distance between the tip end of the steam nozzle 14 and the upper surface of the belt body 30 is less than 1.0 mm, there may be a problem that the opening of the belt body 30, the belt body 30 is broken, and the belt is blown off. Further, when the distance between the front end of the steam nozzle 14 and the upper surface of the belt body 30 is larger than 10 mm, the high-pressure water vapor is used to disperse the force forming the groove on the surface of the belt body 30, and the energy rate of forming the groove on the surface of the belt body 30 is changed. difference.

The pore diameter of the water vapor nozzle 14 is preferably larger than the diameter of the water flow nozzle 12, and the hole pitch of the water vapor nozzle 14 is larger than the hole pitch of the water flow nozzle 12. Thereby, as shown in Fig. 1, the high-pressure water vapor which is ejected from the steam nozzle 14 can be formed while leaving the second acre and the second groove formed by the high-pressure water jet sprayed from the water jet nozzle 12. The first acre and the first groove are formed in the belt body 30. In the belt body 30, there are a plurality of regions of the second acre and the second groove formed by the high-pressure water flow, and the region R ₂ is a region having a large apparent density, and the first mu is formed by the high-pressure water vapor. The area of the mound and the first groove R ₁ , the apparent density of the ligament 30 is reduced by the high pressure water vapor.

The water vapor nozzle 14 preferably has a pore diameter of 150 to 600 μm. When the pore diameter of the steam nozzle 14 is too small, insufficient energy may cause a problem that the fiber is not sufficiently removed. Further, when the pore diameter of the steam nozzle 14 is too large, there is a problem that the substrate is excessively damaged due to excessive energy.

The hole pitch of the water vapor nozzle 14 (the distance between the centers of the adjacent holes) is preferably 3.0 to 8.0 mm. When the hole pitch of the water vapor nozzle 14 is too small, the second acre and the second groove disappear. Conversely, the water vapor nozzle 14 When the hole pitch is too large, the number of the acre and the groove is reduced, the scraping property of the dirt is deteriorated, and it is difficult to maintain the bulkiness.

A first acre and a first groove are formed on the upper surface of the belt body 30 by high-pressure water vapor, and a support body 41 may be formed on the lower surface of the belt body 30 (the side of the support body 41 side of the belt body 30). The pattern corresponds to a bump that is not shown. In addition, under the belt body, the mucus and the groove may be formed by the high-pressure water flow, or the acre and the groove may be formed by the high-pressure water vapor.

Then, as shown in FIG. 3, the belt body 30 is transferred to the belt conveyance belt 18 by the suction pickup 17. Then, the tape body 30 is further transferred to the belt conveyance belt 19, and then transferred to the drying drum 20. The drying drum 20 is, for example, a Yankee dryer, and the belt body 30 is attached to a drum heated to about 160 ° C by steam, and the belt body 30 is dried. Then, the dried belt body 30 is taken up by the winder 22 as a non-woven fabric.

In the case of the non-woven fabric of the aspect shown in Fig. 1, the hole pitch of the water flow nozzle 12 coincides with the interval d _{6 of the} adjacent two second grooves, and the hole pitch of the water vapor nozzle 14 is adjacent to the adjacent one. The interval d _{4 of the} two first grooves is identical.

The non-woven fabric of the aspect shown in Fig. 2 is obtained by spraying water vapor at the position of the arrow described in the upper part of Fig. 2 . In other words, the interval between the two first grooves 4, 4 adjacent to each other across the second acre and the second groove is p1, and the first groove adjacent to the third acre 7 is adjacent. When the interval between the groove 4 and the third groove 8 becomes p2, the hole pitch of the water vapor nozzle 14 will be repeated by p1/p2/p2, and the pitch of the water flow nozzle will be the interval d ₆ of the adjacent second groove. In this case, a non-woven fabric of the aspect shown in Fig. 2 can be obtained.

The hole pitch of the steam nozzle 14 is as shown in Fig. 2, and the interval between the larger ones is preferably 3.0 to 8.0 mm, and the smaller one is preferably 2.0 to 2.5. Mm.

Fig. 9 is a view showing another example of a nonwoven fabric manufacturing apparatus for manufacturing the nonwoven fabric of the present invention.

In the nonwoven fabric manufacturing apparatus 10 shown in FIG. 9, a high-pitch water flow from the water flow nozzle 12 forms a fine pitch of mounds and grooves on the upper surface of the belt body 30 (hereinafter referred to as "B surface"), and borrows By adjusting the water jet conditions, the fine grooves and the grooves are formed on the opposite side of the belt body 30 (hereinafter referred to as "A surface"). The belt system after the water jet is transferred to the belt conveyance belt 18 by the suction pickup 17, and then transferred to the belt conveyance belt 19, and then transferred to the drying drum 20. The drying drum 20 is, for example, a Yankee dryer, and the belt body 30 is attached to a drum heated by steam to dry the belt body 30. The nonwoven fabric manufacturing apparatus shown in Fig. 9 is capable of adjusting the humidity percentage of the belt body 30 before entering the steam injection step. The percentage of humidity of the belt 30 before entering the steam injection step is preferably from 10 to 45%. Here, the humidity percentage (%) means the number of g of moisture contained in 100 g of the total mass of the aqueous belt 30. When the humidity percentage of the belt body 30 is too small, the hydrogen bonding strength between the fibers of the belt body 30 becomes strong, and the energy required to loosen the fibers of the belt body 30 by the steam described later becomes extremely high. Conversely, when the humidity percentage of the belt body 30 is too large, the energy required to dry the belt body 30 to a predetermined humidity percentage by the steam described later becomes very high.

Next, the belt 30 is sent to the steam injection step. Steam jet In the shooting step, the belt body 30 moves toward the mesh-like outer peripheral surface of the cylindrical suction drum 15. At this time, the water vapor is sprayed on the belt 30 from the steam nozzle 14 disposed above the outer peripheral surface of the suction drum 15. Although two rows of water vapor nozzles 14 are illustrated in Fig. 9, they may be one or three or more columns. In the case of the non-woven fabric manufacturing apparatus of Fig. 9, the surface of the belt to which the water vapor is sprayed is the opposite surface (surface A) from which the surface of the water jet is sprayed. A suction device is provided inside the suction drum 15, and the water vapor sprayed from the water vapor nozzle 14 is sucked by the suction device. The first acre 3 and the first groove 4 are formed on the A side of the belt body 30 by the water vapor sprayed from the steam nozzle 14.

One of the steam nozzles 14 disposed above the suction drum 13 is exemplified in FIG. Fig. 10 shows an example in which the water vapor nozzles 14 are arranged in a line. The steam nozzle 14 sprays a plurality of water vapors 51 arranged in the width direction (CD) of the belt body 30 toward the belt body 30. As a result, the A side of the belt body 30 is formed with a plurality of grooves 52 which are arranged in the width direction of the belt body 30 and extend in the machine direction (MD). The groove 52 corresponds to the first groove 4.

The belt body in which water vapor is sprayed is transferred to the drying drum 21 as shown in Fig. 9. The drying drum 21 is, for example, a Yankee dryer, and the belt body 30 is attached to a drum heated by steam to dry the belt body 30. The belt body 30 after drying the drum 21 must be sufficiently dried. Specifically, the moisture percentage of the belt body 30 after passing through the drying drum 21 is preferably 5% or less. The dried belt body 30 is taken up by the winder 22 as a non-woven fabric.

The high-pressure water flow entanglement treatment entangles the fibers to tighten the belt (high density) to increase the strength of the belt. The high-pressure steam treatment releases the fibers (low density) to make the belt bulky. At this time, because of the high pressure water flow processor energy It is higher, so in the high-pressure steam treatment, only a part of the belt is loosened, so that the fibers can be shaped without dispersion.

According to the present invention, a part of the water flow undulation non-woven fabric is subjected to a high-pressure steam spray treatment to form a convex-concave structure having a different sheet volume, whereby a portion having a large volume (small volume) when the liquid is impregnated is concentrated by the capillary phenomenon. When a portion having a large amount of liquid and a small portion are present in a cross-sectional view, a liquid oozing area and a liquid absorbing area can be formed at the time of wiping, and as a result, a sheet which is easy to cause the smear to fall off and which has little residual moisture can be formed.

The nonwoven fabric of the present invention is used to make a wet tissue. Wet wipes can be made by imparting a liquid to the non-woven fabric. The amount of liquid is, for example, three times the dry mass of the nonwoven fabric. In the case of a liquid, it is typically distilled water, but other mixed solutions of a preservative such as propylene glycol or p-hydroxybenzoate can be exemplified.

[Examples] Example 1

Using the nonwoven fabric manufacturing apparatus 10 shown in Fig. 9, a nonwoven fabric as will be described later is manufactured.

A non-woven raw material is prepared, which comprises: 70% by mass of Conifer Tree Bleached Kraft Pulp (NBKP) (Canadian Freeness Standard (cfs) 700 cc), and 嫘萦 (DAIWABO RAYON Co., Ltd. manufactured by DAIWABO RAYON Co., Ltd.) having a fineness of 1.1 dtex and a fiber length of 7 mm. ) 30% by mass. The raw material supply head 11 was used to supply a nonwoven fabric raw material to a support for forming a belt (the OS80 manufactured by Japan Hier Kang Co., Ltd.), and the nonwoven fabric raw material was dehydrated using a suction box to form a belt. The basis weight of the belt (dry basis) was 50 g/m ² .

Then, two high pressure water jet nozzles are used to spray the high pressure water stream to the belt body. At this time, the high-pressure water flow energy of each high-pressure water jet nozzle is 0.142 kW/m ² . Since two high-pressure water flow nozzles are used to spray the high-pressure water flow to the belt body, the high-pressure water flow energy of the high-pressure water jet sprayed to the belt body is 0.284. kW/m ² . The high pressure water jet nozzle has an aperture diameter of 92 μm, a hole pitch of 0.5 mm, and a belt travel speed of 70 m/min. An acre and a groove structure having a pitch of 0.5 mm were formed by spraying a water jet on the water jet surface of the belt, and an acre and a groove structure having a pitch of 0.5 mm were also formed on the opposite side of the water jet surface.

The belt after the water jet is sprayed is sent to the steam injection step through two belt conveying conveyors and a Yankee dryer.

In the steam injection step, two water vapor nozzles are used to perform high-pressure steam injection on the opposite side of the water jet surface of the belt. At this time, the pressure of the high-pressure steam is 0.7 MPa, the temperature of the high-pressure steam is about 175 ° C, the distance between the tip of the steam nozzle and the upper surface of the belt is 2.0 mm, the aperture of the steam nozzle is 500 μm, and the hole spacing is 4.0. The traveling speed of the mm and the belt body is 70 m/min.

Then, the belt body is sent to a coiler through a Yankee dryer and coiled into a non-woven fabric.

A photograph (wet state) of the water jet surface of the belt after the water jet is sprayed is shown in Fig. 11.

Photograph of water vapor ejection surface of the belt after spraying water vapor (wet State) is shown in Figure 12.

A photograph of the water vapor ejection surface of the obtained non-woven fabric (dry state) is shown in Fig. 13.

For the obtained non-woven fabric, measure the basis weight of the non-woven fabric, the height h _{3 of the} first acre (when dry), the height h of the second acre hill h ₅ (when dry), the apparent density of the region R ₁ , the region R apparent _density, dry tensile strength, dry tensile ductility, wet tensile strength and wet tensile ductility. The measurement results are shown in Table 1.

Further, a wet tissue was prepared by impregnating the obtained non-woven fabric with distilled water of three times the mass of the dry mass of the non-woven fabric. The artificial soil wiping test was carried out using the prepared wet tissue, and the dirt removal rate was measured for the high pressure water vapor ejection surface. The measurement results are shown in Table 1.

Example 2

A nonwoven fabric was produced under the same conditions as in the first embodiment except that the water vapor nozzle pitch was changed to 3 mm. The obtained non-woven fabric was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

Comparative example 1

A nonwoven fabric was produced under the same conditions as in the performance of the column 1, except that steam spraying was not performed. The obtained non-woven fabric was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

Comparative example 2

A nonwoven fabric was produced under the same conditions as in the first embodiment except that the water vapor nozzle pitch was changed to 2 mm. The acre and the groove formed by the water jet on the A side disappeared due to the water vapor spray, and on the A side of the obtained non-woven fabric, there is only the first acre and the first formed by the jet of water vapor. The groove, and there is no second acre and second groove formed by water jet. The obtained non-woven fabric was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

Example 3

A non-woven fabric was produced under the same conditions as in the performance of the column 1, except that the water vapor nozzle pitch was changed to a repeating order of 5 mm / 2 mm / 5 mm / 2 mm. A photograph of the water-jet ejecting surface of the obtained non-woven fabric (photographed in a state of being wound into a roll) is shown in Fig. 14. The obtained non-woven fabric was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

In addition, the percentage of the humidity of the belt before the steam injection, the percentage of the humidity of the belt after the steam injection, the percentage of the belt body moisture during the coiling, the weight per unit area of the non-woven fabric, the dry thickness, the height of the first acre hill h ₃ (dry), Height of two acres of hills h ₅ (when dry), apparent density of zone R ₁ , apparent density of zone R ₂ , dry tensile strength, dry tensile ductility, wet tensile strength, wet tensile ductility and soil removal The rate was measured as follows.

[% moisture concentration of the belt before steam injection]

The strip dried by the drying drum 20 was sampled at a size of 30 cm × 30 cm, and the outlet mass (W ₁ ) of the drying drum 20 was measured, and then the sample piece was allowed to stand in a constant temperature bath at 105 ° C for 1 hour and the mass after drying was measured ( D ₁ ). The moisture percentage (%) of the belt before the water vapor spray was calculated by the following formula. In addition, the moisture percentage of the belt before steam injection is an average of 10 measured values.

Percentage of humidity of the belt before steam injection (%) = (W _{1 -} D ₁ ) / W ₁ × 100

[% of moisture in the belt after steam injection]

A strip of the high-pressure water vapor jetted from the water vapor nozzle 14 is sampled on a suction drum 15 by a size of 30 cm × 30 cm, and the mass (W ₂ ) after passing through the steam nozzle 14 is measured, and then the sample piece is taken at 105. The constant temperature bath at ° C was allowed to stand for 1 hour and the mass after drying (D ₂ ) was measured. The percentage humidity (%) of the belt after water vapor injection was calculated by the following formula. In addition, the moisture percentage of the belt after steam injection is an average of 10 measured values.

Percentage of moisture of the belt after steam injection (%) = (W _{2 -} D ₂ ) / W ₂ × 100

[% of body moisture when coiling]

The wound tape was sampled at a size of 30 cm × 30 cm, and the mass (W ₃ ) after the coiling was measured. Then, the sample piece was allowed to stand in a constant temperature bath at 105 ° C for 1 hour, and the mass after dry (D ₃ ) was measured. The percentage of the body moisture (%) at the time of winding was calculated by the following formula. Further, the percentage of the body moisture at the time of winding is the average of the measured values of N=10.

Percentage of belt moisture during coiling (%) = (W _{3 -} D ₃ ) / W ₃ × 100

[non-woven unit weight]

The basis weight of the non-woven fabric is calculated by dividing the absolute dry sample mass D ₃ (g) when the percentage of the belt moisture at the time of winding is divided by the area (0.09 m ² ). The non-woven basis weight is the average of 10 measured values.

[the height of the first acre hill h ₃ (when dry) and the height of the second acre hill h ₅ (when dry)]

The sample of the non-woven fabric (dry product) is impregnated with liquid nitrogen and frozen, and then cut with a razor. After returning to normal temperature, an electron microscope (for example, Keynes VE7800) is used to take a photograph of 50 times magnification, and the first acre is measured. The height h ₃ (when dry) and the height of the second acre hill h ₅ (when dry). The reason why the sample is frozen is to prevent thickness variation caused by compression at the time of cutting with a razor.

[Apparent Density of Regions R ₁ and R ₂ ]

The cross-section of the non-woven fabric was imaged by magnifying 50 times or more by a microscope or the like, and the number of fibers in the unit area of the thickness of the region R ₁ or R ₂ × the width of 0.5 mm was measured, and the fiber weight was calculated from the result, and the appearance was calculated. density.

Further, the apparent density difference was calculated by the following formula.

Apparent density difference (%) = (ρ2-ρ1) / ρ1 × 100

The apparent density of the ρ1 region R _{1 and} the apparent density of the ρ ₂ region R ₂ .

[dry tensile strength]

From the nonwoven fabric to be produced, a long test piece of 25 mm width in which the longitudinal direction is the mechanical direction of the belt body and a long test piece of 25 mm width in the width direction of the belt body were cut out to prepare a sample for measurement. . For the measurement of the machine direction and the width direction, a tensile tester (available from Shimadzu Corporation, a tabletop precision universal tester type AGS-1kNG) with a maximum load weight of 50 N was used. For the measurement samples, the tensile strength was measured under the conditions of a jig pitch 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 sample for measurement in the machine direction and the width direction was defined as the dry tensile strength in the machine direction and the width direction.

[dry stretch ductility]

From the manufactured non-woven fabric, a long strip test piece of 25 mm width in which the longitudinal direction is the mechanical direction of the belt body is cut, and the length direction is the width of the belt body. A strip test piece of 25 mm width in the direction was used to prepare a sample for measurement. For the measurement of the machine direction and the width direction, a tensile tester (available from Shimadzu Corporation, a tabletop precision universal tester type AGS-1kNG) with a maximum load weight of 50 N was used. For the measurement samples, the tensile ductility was measured under the conditions of a jig pitch of 100 mm and a tensile speed of 100 mm/min. Here, the tensile ductility refers to a value calculated by dividing the maximum spread (mm) when the measurement sample is pulled by the tensile tester by the jig pitch (100 mm). The average value of the tensile ductility of the three measurement samples of the sample for measurement in the machine direction and the width direction was defined as the dry stretch ductility in the machine direction and the width direction.

[wet tensile strength]

From the nonwoven fabric to be produced, a long test piece of 25 mm width in which the longitudinal direction is the mechanical direction of the belt body and a long test piece of 25 mm width in the width direction of the belt body were cut out to prepare a sample for measurement. The measurement sample was impregnated with water (water content ratio: 250%) which was 2.5 times the mass of the measurement sample. Then, a tensile tester (available from Shimadzu Corporation, a tabletop precision universal testing machine type AGS-1kNG) with a dynamometer with a maximum load of 50 N was used for the measurement of the machine direction and the width direction. The tensile strength was measured for the three measurement samples under the conditions of a jig pitch 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 sample for measurement in the machine direction and the width direction was defined as the wet tensile strength in the machine direction and the width direction.

[wet stretch ductility]

From the nonwoven fabric to be produced, a long test piece of 25 mm width in which the longitudinal direction is the mechanical direction of the belt body and a long test piece of 25 mm width in the width direction of the belt body were cut out to prepare a sample for measurement. The measurement sample was impregnated with water (water content ratio: 250%) which was 2.5 times the mass of the measurement sample. Then, a tensile tester (available from Shimadzu Corporation, a tabletop precision universal testing machine type AGS-1kNG) with a dynamometer with a maximum load of 50 N was used for the measurement of the machine direction and the width direction. Tensile ductility was measured for the three measurement samples under the conditions of a jig pitch of 100 mm and a tensile speed of 100 mm/min. The average value of the tensile ductility of the three measurement samples of the sample for measurement in the machine direction and the width direction was defined as the wet stretchability in the machine direction and the width direction.

[dirt removal rate]

Simulated soil was prepared by using a paste having a blending ratio of 12.6 mass% of carbon black, 20.8% by mass of tallow extremely hardened oil, and 66.6 mass% of flowing paraffin. The paste and hexane were mixed at a ratio of 85:15 (mass ratio). A 0.05 ml hexane dilution paste was dropped on the glass plate. After drying in a high temperature and high humidity chamber (20 ° C, humidity 60%) for 24 hours, the color tone was scanned by a scanner. The friction coefficient measuring device of Test Machine Industry Co., Ltd. was subjected to a wiping test (1 time) under the conditions of 150 mm/min and a load of 60 g. After the test, the change in hue is scanned by the scanner and will be scanned The rate of change of the hue of the area of 16.9 mm × 16.9 mm in the area after the drawing was calculated by the following formula as the dirt removal rate.

Dirt removal rate (%) = (C ₀ - C ₁ ) / C ₀ × 100

Among them, C ₀ is the color tone before wiping, and C ₁ is the color tone after wiping.

It can be judged that the larger the color tone removal rate, the more the dirt can be removed. The measurement was performed with N number = 3, and the average of three times was taken as the dirt removal rate.

[Industry use possibility]

The nonwoven fabric of the present invention is suitable for use in making wet wipes.

1‧‧‧nonwoven

3‧‧‧ first mu hill

4‧‧‧First trench

5‧‧‧ second mu hill

6‧‧‧Second trench

10‧‧‧Nonwoven manufacturing equipment

11‧‧‧Material supply head

12‧‧‧Water jet nozzle

13‧‧‧Attraction box

14‧‧‧Water Vapor Nozzle

15‧‧‧Attraction roller

16‧‧‧Band formation conveyor belt

17‧‧‧Attracting pickers

18,19‧‧‧Band handling conveyor belt

20, 21‧‧‧ Drying roller

22‧‧‧Winding machine

30‧‧‧Band

31‧‧‧High pressure water flow

32‧‧‧ trench

41‧‧‧Support

51‧‧‧High pressure water vapor

52‧‧‧ trench

Fig. 1 is a schematic enlarged perspective view of the nonwoven fabric of the present invention.

Figure 2 is a schematic enlarged cross-sectional view of a non-woven fabric of another aspect of the present invention.

Fig. 3 is a view showing an example of a nonwoven fabric manufacturing apparatus for producing the nonwoven fabric of the present invention.

Fig. 4 is a view showing an example of a water flow nozzle.

Fig. 5 is a view for explaining the principle of entanglement of the fibers of the belt by water jet.

Fig. 6 is a cross-sectional view in the width direction of the belt body to be sprayed with water.

Fig. 7 is a view showing an example of a water vapor nozzle.

Figure 8 is a diagram for explaining the principle of loosening the fibers of the belt by steam spraying to form grooves and acres.

Figure 9 is a view showing the manufacture of a nonwoven fabric for manufacturing the nonwoven fabric of the present invention. Other examples of devices.

Fig. 10 is a view showing another example of the water vapor nozzle.

Fig. 11 is a photograph (wet state) of the water jet surface of the belt after the water jet was sprayed in Example 1.

Fig. 12 is a photograph (wet state) of the water vapor ejection surface of the belt after the water vapor injection in Example 1.

Fig. 13 is a photograph of a water vapor ejection surface of a non-woven fabric (dry state) obtained in Example 1.

Fig. 14 is a photograph of a water vapor ejection surface of a non-woven fabric (dry state) obtained in Example 3.

1‧‧‧nonwoven

3‧‧‧ first mu hill

3T‧‧‧The top of the first mu hill

4‧‧‧First trench

4B‧‧‧The bottom of the first trench

5‧‧‧ second mu hill

5T‧‧‧The top of the second mu hill

6‧‧‧Second trench

6B‧‧‧ bottom of the second trench

d ₃ ‧‧‧The interval between the first acre

d ₄ ‧‧‧Interval of the first groove

d ₅ ‧‧‧Separation of the second acre

d ₆ ‧‧‧Separation of the second groove

h ₃ ‧‧‧The top height of the first acre

h ₄ ‧‧‧ bottom height of the first groove

h ₅ ‧‧‧The height of the top of the second acre

h ₆ ‧‧‧ bottom height of the second trench

R ₁ ‧‧‧The first acre and the area where the first trench is located

R ₂ ‧‧‧Second acre and second trench area

Claims (16)

A non-woven fabric for wet tissue, which is a non-woven fabric for wet tissue containing absorbent fibers, characterized in that at least one surface of the non-woven fabric is formed with a plurality of first mu hills, first grooves, and second portions extending in the same direction. The top of the first acre is higher than the top of the second acre, and the height of the top of the second acre is higher than the bottom of the second groove, and the bottom of the second groove The height is higher than the height of the bottom of the first trench, the first trench is located between the two adjacent first mu hills, and the plurality of second acre and the second trench are located in the absence of the first trench and Between two adjacent first mu hills adjacent to each other, the interval between two first mu hills adjacent to each other through the first trench is higher than the two second mu hills adjacent to each other across the second trench The interval is wider. The non-woven fabric according to claim 1, wherein the apparent density of the non-woven dry state of the area of the first acre and the first groove is higher than the dry state of the area of the second acre and the second groove. The density of view is smaller. For example, the non-woven fabric described in claim 1 or 2, wherein the difference between the top height of the first acre and the top height of the second acre is 0.1 mm or more. The non-woven fabric of claim 1 or 2, wherein the absorbent fiber comprises cellulose. The non-woven fabric according to claim 1 or 2, wherein the liquid holding portion and the non-holding portion can be visually confirmed when the liquid is impregnated. The non-woven fabric according to claim 1 or 2, wherein 30% or more of the fibers constituting the nonwoven fabric are absorbent fibers. For example, the non-woven fabric according to the first or second aspect of the patent application, wherein the apparent density of the non-woven dry state of the first acre and the first groove is 0.030 to 0.10 g/cm ³ , and the second acre The apparent density of the non-woven dry state in the region where the second groove is located is 0.12 to 0.20 g/cm ³ . The non-woven fabric according to claim 1 or 2, wherein the interval between the two first acres adjacent to the second acre and the second groove is 3 mm or more. The non-woven fabric according to claim 1 or 2, wherein the fiber constituting the non-woven fabric has a fiber length of 20 mm or less. For example, in the non-woven fabric described in claim 1 or 2, the difference between the height of the top of the second acre and the height of the bottom of the second groove is 0.05 to 0.10 mm. For example, the non-woven fabric mentioned in item 1 or 2 of the patent application scope, The interval between the two second acres adjacent to each other across the second groove is 0.3 to 1.0 mm. For example, the non-woven fabric described in claim 1 or 2, wherein the difference between the height of the top of the first acre and the height of the bottom of the first groove is 015 to 0.60 mm. For example, the non-woven fabric described in claim 1 or 2, wherein a third acre is further formed between the two first mu hills adjacent to the second acre and the second trench The hills, and the top height of the third acre is higher than the top of the second acre. The non-woven fabric according to claim 1 or 2, wherein the first acre and the first groove are formed by steam spraying, and the second acre and the second groove are sprayed by water. Formed. A method for producing a non-woven fabric for a wet tissue as described in claim 1, comprising: supplying a mixture of fibers and water containing absorbent fibers to a support, and forming an aqueous belt on the support; a step of arranging the fibers by water jet nozzles arranged at equal intervals along the width direction of the strip body to align the fibers; and arranging at a larger interval from the width of the water jet nozzles in the width direction of the strip body a water vapor nozzle for performing a steam injection on a belt after the water jet is sprayed; The step of drying the belt after the steam is sprayed. A wet tissue made by impregnating a non-woven fabric according to any one of claims 1 to 14.