JP4476139B2 - Method for manufacturing absorbent article - Google Patents

Description

  The present invention relates to a method for producing various absorbent articles including disposable diapers and sanitary napkins.

  The present applicant has previously proposed an absorbent article in which a plant extract having a skin care effect is applied to a surface sheet or an absorbent layer (see Patent Document 1). According to such an absorbent article, a user's skin irritation can be efficiently suppressed without impairing the absorption performance of the superabsorbent polymer contained in the absorbent layer.

  The plant extract is applied to the surface sheet by, for example, applying a coating solution containing the plant extract to the surface sheet or kneading it into the constituent fibers of the surface sheet. When applying a coating solution containing a plant extract to the top sheet, it is preferable to use a non-contact coating method from the viewpoint of not damaging the texture of the sheet. Such a coating method includes, for example, a curtain spray method using a non-contact coating apparatus such as a slot spray gun.

  The slot spray gun has a slot-like discharge port and a discharge port for compressed air adjacent to the discharge port, and has a structure in which various coating materials are conveyed to the compressed air and discharged (for example, patents). Reference 2). If an application liquid that is a low-viscosity fluid is to be applied using a slot spray gun, the application liquid flows down in the form of droplets from the discharge port due to the low viscosity, and uniform application is not easy. In particular, when the discharge speed is low, the flow of the coating solution is remarkable.

JP 2000-45391 A JP-A-11-347459

  Accordingly, an object of the present invention is to provide a method for producing an absorbent article that can eliminate the above-mentioned drawbacks of the prior art.

This invention is a manufacturing method of an absorbent article which has the process of apply | coating a low-viscosity fluid on the surface which contacts a user's skin using a non-contact-type coating device in the state of a viscosity of 50-1000 mPa * s, ,
The non-contact type coating apparatus has a long groove-like fluid discharge port for discharging the fluid and air discharge ports on both sides thereof, and the fluid discharge port has a structure protruding from the air discharge port,
The fluid discharge port is provided with a plurality of comb-like partition portions extending in the fluid discharge direction to reduce the opening area of the fluid discharge port, and the low-viscosity fluid is discharged through the partition portions. And the compressed air is discharged from the air discharge port, and the low-viscosity fluid is applied at an outlet speed of 30 to 50 mm / s over the entire width of the fluid discharge port.
When the fluid discharge port is viewed in plan, the ratio (the former / the latter) of the total area of the portions where the fluid is discharged and the total area of the partition portions is 1/2 to 4/5. Thus, the said objective is achieved by providing the manufacturing method of the absorbent article which distributes this partition part .

  According to the production method of the present invention, the fluid outlet speed in the coating apparatus is increased, so that a low-viscosity fluid can be stably applied, and an absorbent article in which the fluid is uniformly applied can be obtained.

  The present invention will be described below based on preferred embodiments with reference to the drawings. FIG. 1 shows a disposable diaper as an example of an absorbent article manufactured according to a preferred embodiment of the manufacturing method of the present invention. 2 is a cross-sectional view taken along line II-II in FIG. The diaper 1 of this embodiment is disposed between a liquid-permeable top sheet 2, a liquid-impermeable or water-repellent (hereinafter collectively referred to as liquid-impermeable) back sheet 3, and both sheets. The liquid-retaining absorbent body 4 is provided and formed substantially vertically long.

  As the surface sheet 2, a non-woven fabric, a material in which a large number of holes are formed, or a perforated film can be used. The top sheet 2 has air permeability in addition to being liquid permeable. The back sheet 3 has moisture permeability in addition to being liquid impermeable. In the present invention, the term “air permeability” mainly refers to a property related to air permeability. In addition, the term “moisture permeability” mainly refers to a property related to water vapor permeability. Being breathable means not only air but also water vapor permeability. Similarly, being moisture permeable means not only water vapor but also air permeability.

  The diaper 1 has an hourglass shape in which both side edges of the crotch portion are curved in an arc shape and the central portion in the longitudinal direction is bound inward as a whole. The top sheet 2 and the back sheet 3 respectively extend outward from the left and right side edges and the front and rear end edges of the absorber. The top sheet 2 has a width dimension that is smaller than the width dimension of the back sheet 3. As a result, the left and right side edges 2a and 2b of the top sheet 2 are terminated more inward in the width direction than the left and right side edges 3a and 3b of the back sheet 3.

  An exterior sheet 5 having air permeability is disposed on the outer surface of the back sheet 3. The exterior sheet 5 and the back sheet 3 are bonded together by, for example, a hot melt adhesive. In order not to impair the moisture permeability of the back sheet 3, the hot melt pressure-sensitive adhesive is applied in an intermittent pattern such as bead coating or spiral coating. The exterior sheet 5 extends outward from the left and right side edges and the front and rear end edges of the top sheet 2 and the back sheet 3 to define the outline of the diaper 1. As a material of the exterior sheet 5, for example, various nonwoven fabrics are used.

  A pair of three-dimensional gathers 6 and 6 and a pair of leg gathers 7 and 7 are formed on both sides in the longitudinal direction of the diaper 1 by disposing elastic members, respectively. Both gathers 6 and 7 extend in the longitudinal direction of the diaper 1. The three-dimensional gather 6 is formed from a sheet material 62 for forming a three-dimensional gather having an elastic member 61. The function of the three-dimensional gather 6 is a barrier for preventing the liquid diffused in the lateral direction without being absorbed by the absorber 4 from further diffusing in the lateral direction. It is preferable that. Moreover, it is preferable to have air permeability from a viewpoint of suppressing the humidity rise in the wearing during wearing of the diaper 1. Taking these into consideration, it is preferable to use a non-woven fabric that has water repellency or has been subjected to water repellency as the sheet material 62.

  The sheet material 62 has a vertically long shape extending in the longitudinal direction of the diaper 1, and an elastic member 61 is fixed to the one side edge in an extended state. The sheet material 62 is joined to the topsheet 2 along the longitudinal direction of the diaper 1 at positions outside the left and right side edges of the absorbent body 4 in the width direction. The joint portion is a rising base end portion 6 a of the three-dimensional gather 6.

  Furthermore, the sheet material 62 extends outward in the width direction from the base end portion 6a, and the extended portion is joined to the back sheet 3 and the exterior sheet 5 to form a leg flap L (see FIG. 2). ing. In the leg flap L, a portion closer to the inner side in the width direction is formed by joining the sheet material 62, the back sheet 3, and the exterior sheet 5. The portion closer to the outside is formed by joining the sheet material 62 and the exterior sheet 5. The leg gathers 7 formed on the leg flap L have one or a plurality (in the present embodiment, a plurality) of the leg gathers L between the sheet material 62 and the exterior sheet 5 at a portion closer to the outside of the leg flap L. The leg elastic member 71 is formed in a substantially linear shape.

  At the front and rear ends of the diaper 1, the front sheet 2, the back sheet 3, and the exterior sheet 5 extend from the front and rear end edges of the absorber 4, and these are joined to each other and a waist flap W extending in the width direction of the diaper 1 (see FIG. 1). In the waist flap W, one or a plurality of waist elastic members 81 extending in the width direction are arranged between the sheets described above (one in the present embodiment) to form the waist gathers 8.

  In the diaper 1, the surface which contacts a user's skin is given the chemical | medical agent which has a predetermined effect with respect to a user's skin. Specifically, a chemical is applied to the top sheet 2 in the diaper 1. The chemical | medical agent is given by applying the coating liquid containing this to the surface sheet 2. FIG. By the chemical | medical agent being given to the surface sheet 2, a user's skin's damage | wound, a rash, and inflammation are suppressed / healed effectively.

  The drug can be used without particular limitation as long as it has a predetermined effect on the user's skin. Examples of the drug include the following (1) to (4). These drugs may be used alone or in combination of two or more.

Moisturizers such as squalane, squalene, 1,3-butylene glycol, propylene glycol, glycerin and the like.
(2) Isopropyl myristyl, isopropyl propanol, petrolatum, cetanol, stearyl alcohol, liquid paraffin, silicone oil, animal and vegetable oils (olive oil, jojoba oil, safflower oil, etc.), monoglyceride, diglyceride, 2-ethyl used as cosmetic oils Triglycerides such as hexanoic acid triglyceride, aliphatic ethers (myristyl-1,3-dimethylbutyl ether, palmityl-1,3-dimethylbutyl ether, stearyl-1,3-dimethylbutyl ether, palmityl-1,3-methylpropyl ether, stearyl- 1,3-methylpropyl ether and the like), bisabolol, isostearyl-cholesterol ester and the like.
(3) Various waxes such as paraffin wax, C ₁₂ -C ₂₂ fatty acid, C ₁₂ -C ₄₄ fatty acid ether, C ₁₂ -C ₂₂ fatty alcohol, fatty acid sorbitan ester (any of monoester, diester and triester may be used) .), Polyoxyethylene fatty acid sorbitan ester (any of monoester, diester and triester), metal experience (magnesium stearate, etc.), sucrose fatty acid ester, cyclodextrin fatty acid ester, silicone resin, and alkyl Silicone etc.
(4) A diamide derivative represented by the following formula (1) or the following formula (2) described in International Publication No. WO00 / 61097 can also be used as an oily skin care agent.

Furthermore, the following agents (1) and (2) may be appropriately mixed and used for the above-mentioned agents.
(1) Agents having a skin care effect on the user's skin, for example, anti-inflammatory agents such as plant extracts, guaiazulene, tannin, gallic acid derivatives and bisabolol. The “skin care effect” means the overall effect of normalizing skin conditions such as skin damage, rash prevention, and anti-inflammation. Examples of the plant extract include oat extract, seaweed extract (Hibamata), straw extract, hamamelis extract, bituminous extract, asunaro extract, aloe extract, buckwheat extract, horsetail extract, chamomile extract, eucalyptus extract, peach extract and the like.

(2) Organic or inorganic powders that adhere to the skin to reduce friction and impart a smooth feeling and prevent skin damage, such as silicone beads, nylon beads, cigarol, chitosan beads, silk powder, Nε-lauroyl-L-lysine, sodium cetyl phosphate, lauroyl taurine calcium and the like.

  Each above-mentioned medicine is given by applying the application liquid containing this medicine to the surface of the diaper 1 on the surface sheet side. That is, after producing a diaper using each member which comprises the diaper 1, a coating liquid is apply | coated to the skin contact surface of this diaper 1. A method of applying a coating solution to a member constituting the diaper before producing the diaper is also conceivable. However, when this method is employed, the coating liquid may adhere to the diaper processing machine while the member coated with the coating liquid is transported, and dirt may adhere to the processing machine. Therefore, in the present embodiment, in order to prevent such a fear from occurring, the coating liquid is applied to the produced diaper. In the present embodiment, the non-contact coating apparatus 10 shown in FIG. 3 is used for coating the coating liquid.

  As shown in FIG. 4, the coating apparatus 10 has two halved die blocks 11 and 12. Further, two air blocks 13 and 14 are provided. The air blocks 13 and 14 are attached to the lower portions of the die blocks 11 and 12. The die blocks 11 and 12 have protrusions 15 and 16 that hang downward. The die blocks 11 and 12 together with a shim plate 24 described later form a coating liquid slot (not shown) that is a flow path. The coating liquid slot is defined by the opposing surfaces of the die blocks 11 and 12. The lower end of the coating liquid slot is opened to the outside as a long groove-like fluid discharge port. The width of the fluid discharge port is an application width when the application liquid is applied to the skin contact surface of the diaper 1.

  The die block 11 has a coating liquid flow path 17 which is open on the upper surface thereof and extends in the thickness direction of the die block 11. The flow path 17 guides the applied coating liquid to the cavity portion 18 of the die block 11. Each die block 11, 12 has an air flow path 19 that opens on the upper surface and penetrates the die block 11 in the thickness direction. Furthermore, each die block 11, 12 has an inclined surface 20 that hangs obliquely from its lower surface. The inclined surface 20 constitutes a part of an air slot, as will be described later. In addition, by installing a filter between the coating liquid tank (not shown) and the cavity portion 18, it is possible to effectively prevent foreign matter from entering the coating liquid slot.

  The air blocks 13 and 14 have an inclined surface 21. The inclined surface 21 constitutes a part of the air slot. When the air blocks 13 and 14 are attached under the die blocks 11 and 12, these inclined surfaces 21 are opposed to the inclined surfaces 20 described above at a predetermined interval. As a result, an air slot (not shown) is formed by the inclined surfaces 20 and 21.

  The air blocks 13 and 14 have an air flow path 22 that is open on the upper surface and extends in the thickness direction of the air blocks 13 and 14 (the air flow path of the air block 14 is not shown). The air flow path 22 guides the introduced air to the cavity portion 23 of the air blocks 13 and 14 (the cavity portion of the air block 14 is not shown). Further, the air flow path 22 communicates with the air flow path 19 formed in the die blocks 11 and 12 when the air blocks 13 and 14 are attached to the lower portions of the die blocks 11 and 12.

  A shim plate 24 is disposed between the blocks 11 and 12 on the opposing surfaces of the die blocks 11 and 12. The thickness of the shim plate 24 coincides with the thickness of the coating liquid slot which is a flow path for the coating liquid. The shim plate 24 is a rectangular thin plate, and has a U shape with a lower portion cut out into a rectangular shape. The width of the notch in the shim plate 24 matches the width of the fluid discharge port.

  As shown in FIG. 5, the shim plate 24 has a large number of comb teeth 25 at the notch. The comb teeth 25 are arranged in parallel in the width direction of the shim plate 24 at equal intervals. Each comb tooth 25 has a certain width from the base end portion to the tip end portion. However, the shape of the comb teeth 25 is not limited thereto, and for example, as shown in FIG. The lower ends of the comb teeth 25 extend to the fluid discharge port in the coating apparatus 10. As a result, as shown in FIG. 7, in the coating apparatus 10, a large number of comb-like partition portions 27 extending in the discharge direction of the coating liquid are arranged at the fluid discharge ports 26. The coating liquid is discharged through the adjacent partition portions 27.

Further, as shown in FIG. 7, air discharge ports 28 are formed on both sides of the fluid discharge port 26. The air discharge port 28 communicates with the air slot described above.
Note that, from the viewpoint of preventing dripping of the discharged liquid, it is preferable to have a structure in which the coating liquid discharge port projects from the air discharge port. The protruding distance is preferably 0.1 to 5 mm, particularly preferably 0.1 to 2.5 mm.

In the coating apparatus 10 configured as described above, the coating liquid is discharged from the fluid discharge port 26, and compressed air is discharged from the air discharge port 28 so as to sandwich it from both sides, so that the coating liquid is turned into an air flow. It is conveyed and apply | coated to the skin contact surface side of the diaper 1 which is a coating object. In this case, the coating liquid is not discharged from the entire width of the fluid discharge port 26 but is discharged only from the space partitioned by the partition portion 27 (see FIG. 7). Therefore, compared with the case where the coating liquid is discharged from the entire width of the fluid discharge port 27 without providing the partition portion 27, the outlet speed of the coating liquid is increased. As a result, when a low-viscosity fluid is used as the coating liquid, the coating liquid is successfully transported to the air flow without flowing down in the form of droplets, and is applied onto the skin contact surface of the diaper 1. In addition, the coating width of the coating liquid is the same as that when the partition portion 27 is not provided. As described above, in this embodiment, by arranging a large number of partition portions 27 in the fluid discharge ports 26 and discharging the coating liquid through the partition portions 27, the opening area of the fluid discharge ports 26 is reduced. The coating liquid is applied over the entire width of the fluid discharge port 26 in a state of being lowered as compared with the case where it is not provided.

  In order to increase the outlet speed of the coating liquid at the fluid discharge port 26, it is conceivable to make the shim plate 24 extremely thin instead of providing the partition portion 27 as described above. However, an extremely thin shim plate has problems such as bending and is difficult to handle. In addition, when an extremely thin shim plate is used, the thickness of the fluid discharge port is reduced, and accordingly, clogging of foreign matter in the coating apparatus 10 and clogging of foreign matter at the fluid discharge port are likely to occur. Furthermore, if the shim plate is made extremely thin, its production cost becomes very expensive. Therefore, it is extremely difficult to achieve the same effect as the method of the present embodiment by making the shim plate extremely thin.

From the above viewpoint, the thickness of the shim plate 24 in this embodiment, that is, the thickness of the partition portion 27 is preferably 0.05 to 2 mm, particularly preferably 0.1 to 0.2 mm.

  Furthermore, when the fluid discharge port 26 is viewed in a plan view with the viscosity of the coating liquid within the above range (see FIG. 7), the total area of the portions from which the coating liquid is discharged and the total area of the partition portions 27 It is preferable to arrange the partition portion 27 so that the ratio (the former / the latter) is 1/20 to 19/20, particularly 1/2 to 4/5. This ratio is determined by the following policy. First, the coating basis weight and coating width of the coating liquid and the conveyance speed of the diaper 1 are given as initial values. From these initial values, the required coating amount is calculated. Next, the exit speed of the coating liquid is calculated from the coating amount, the thickness of the shim plate 24, and the coating width. When the exit speed is not an appropriate value, the exit speed is calculated again by variously changing the number and width of the partition portions 27 and the distance between the partition portions 27. This operation is repeated to determine an appropriate value for the ratio.

  The ratio of the total area of the portions where the coating liquid is discharged and the total area of the partitioning portion 27 is as described above, and the width of the partitioning portion 27 itself is preferably 0.1 to 2 mm. The width of the portion from which the coating liquid is discharged, that is, the distance between the partition portions 27 is preferably 0.1 to 1 mm, particularly preferably 0.1 to 0.5 mm, from the viewpoint of coating uniformity.

  Considering the above various conditions, the outlet speed of the coating liquid discharged from the fluid discharge port 26 is preferably 30 to 50 mm / s. The distance between the fluid discharge port 26 and the diaper 1 is preferably 5 to 50 mm, particularly preferably 15 to 25 mm.

The coating liquid to be applied by the above method is not particularly limited in the application basis weight, but in the range of 0.05 to 20 g / m ² considering the influence on the absorption performance, skin care effect, texture, and the like. It is preferable to set it within the range of 0.3 to 10 g / m ² . This coating amount can be determined from the weight difference between the coating object before coating and after coating.

  As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment, A various change is possible. For example, in the said embodiment, although the coating liquid containing a chemical | medical agent was mainly apply | coated to the surface sheet 2 of the diaper 1, it replaced with or in addition to this, the three-dimensional gather 7, the leg gather 7, the waist gather of the diaper 1, etc. You may apply to.

  Moreover, in the said embodiment, although the coating liquid containing chemical | medical agents, such as a skin care agent, was apply | coated to the diaper 1, the kind of coating liquid is not restricted to this, The coating liquid containing the agent which can improve the various characteristic of the diaper 1 is used. Can be used.

  Furthermore, in the above-described embodiment, the disposable diaper is used as the application target of the coating liquid, but the application target is not limited to this, and the same applies to other absorbent articles such as sanitary napkins, incontinence pads, panty liners, and the like. it can.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples. Unless otherwise specified, “%” means “% by weight”.

[Example 1]
A disposable diaper having the structure shown in FIGS. 1 and 2 was produced. After assembling the diaper using each member constituting the diaper, a coating solution having the following composition was applied to the top sheet and the three-dimensional gather using the coating apparatus shown in FIGS. The diaper was conveyed at a speed of 200 m / min.

[Coating solution]
The diamide derivative represented by the above formula (2) was used as a coating solution.

  The coating solution was heated to 80 ° C. and supplied to the coating apparatus. The viscosity of the coating solution was 200 mPa · s. The thickness of the fluid discharge port (= the thickness of the shim plate) in the coating apparatus was 0.15 mm, and the width of the comb teeth (partition part) in the shim plate was 0.95 mm. The distance between the comb teeth (partitions) was 0.3 mm. The ratio (the former / the latter) of the total area of the portions from which the coating liquid is discharged to the total area of the partition portions was 0.76. The exit speed of the coating liquid at the fluid discharge port was 42.9 mm / s.

When the skin contact surface of the diaper to which the coating solution was applied under the above conditions was visually observed, it was confirmed that the coating solution was uniformly applied.
[Comparative Example 1]
The coating solution was applied in the same manner as in Example 1 except that a U-shaped shim plate having no comb teeth and having a rectangular lower portion cut out was used. The exit speed of the coating liquid at the fluid discharge port was 14.3 mm / s. When the skin contact surface of the diaper to which the coating solution was applied was visually observed, it was confirmed that uneven coating due to the dripping of the coating solution had occurred.

It is a perspective view which shows the disposable diaper as an example of the absorbent article manufactured according to preferable one Embodiment of the manufacturing method of this invention. It is the II-II sectional view taken on the line in FIG. It is a perspective view which shows the external appearance of a coating device. It is a disassembled perspective view of a coating device. It is a front view which shows a shim board. It is a figure which shows the other shape of a comb tooth. It is a top view which shows the fluid discharge port of a coating device.

Explanation of symbols

1 disposable diaper (absorbent article)
2 Surface Sheet 3 Back Sheet 4 Absorber 5 Exterior Sheet 6 Solid Gather 7 Leg Gather 10 Non-Contact Coating Device 11, 12 Die Block 13, 14 Air Block 24 Shim Plate 25 Comb Teeth 26 Fluid Discharge Port 27 Partition

Claims (5)

A method of manufacturing an absorbent article having a step of applying a low-viscosity fluid under a state of a viscosity of 50 to 1000 mPa · s using a non-contact type coating device on a surface in contact with a user's skin,
The non-contact type coating apparatus has a long groove-like fluid discharge port for discharging the fluid and air discharge ports on both sides thereof , and the fluid discharge port has a structure protruding from the air discharge port,
The fluid discharge port is provided with a plurality of comb-like partition portions extending in the fluid discharge direction to reduce the opening area of the fluid discharge port, and the low-viscosity fluid is discharged through the partition portions. is allowed Rutotomoni by ejecting compressed air from the air discharge opening, said low viscosity fluid was applied at the outlet speed of 30 to 50 mm / s over the entire width of the fluid discharge ports,
When the fluid discharge port is viewed in plan, the ratio (the former / the latter) of the total area of the portions where the fluid is discharged and the total area of the partition portions is 1/2 to 4/5. method of manufacturing an absorbent article for wearing the partition switching unit as. The manufacturing method of Claim 1 which makes the width | variety of the said partition part 0.1-2 mm . The manufacturing method according to claim 1 or 2, wherein a width of a portion from which the fluid is discharged is 0.1 to 1 mm .   The manufacturing method according to any one of claims 1 to 3, wherein a partition having a thickness of 0.05 to 2 mm is used.   The manufacturing method according to any one of claims 1 to 4, wherein a fluid containing a drug having a predetermined effect on a user's skin is used as the fluid, and the fluid is applied mainly to a surface sheet of an absorbent article. .