JP4475979B2 - Method for manufacturing absorbent article - Google Patents

Description

  The present invention relates to a method for stably transferring and adhering an adhesive applied to a peeled interior bag to an absorbent article body when manufacturing absorbent articles such as sanitary napkins and incontinence liners. The present invention relates to a technique for adhering the non-woven fabric in an absorbent article main body arranged in a lower layer (a layer closest to the underwear when worn) and an adhesive.

  Sanitary napkins and incontinence liners are usually packaged and sold one by one for reasons of hygiene and convenience of carrying. In general, in absorbent articles, an adhesive is applied to the back (lowermost layer) of the absorbent main body composed of a top sheet, an absorbent body, a back sheet, etc., to adhere to the underwear when worn. Is done. Many current products are manufactured in a form in which the pressure-sensitive adhesive is covered and protected with a release sheet at the manufacturing stage for the purpose of simplicity and reduction of dust discharge. In recent years, from the viewpoint of improving the fit to underwear, a product in which the back sheet is covered with a nonwoven fabric and the nonwoven fabric is used as the back surface of the absorbent main body is being manufactured.

  When applying an adhesive to the back surface of such an absorptive main body, it is possible to use the inversion apparatus 100 as shown in FIG. 4, for example. In the reversing device 100, the release sheet 103 conveyed in the direction A by the first reversing machine 101 is conveyed in the direction B while being reversed and reversed with the first reversing roller 104 as a boundary. The absorbent main body 105 and the release sheet 103 are joined while the absorbent main body 105 transported in the direction B is joined to the release sheet 103 by the second reverse roller 106. In this case, in the first reversing machine 101, the heated hot melt adhesive 107 is sprayed or applied from the hot melt gun 108 in advance, and the hot melt adhesive 107 is applied to the surface of the release sheet 103. By sticking the sheet 103 and the back sheet of the absorbent article 105, the adhesive is transferred and bonded to the back surface of the absorbent article.

  On the other hand, Patent Document 1 describes a double-sided tape having a two-layer structure of a hot melt adhesive.

Japanese Utility Model Publication No. 52-3295

  However, when the adhesive applied to the release sheet is transferred and adhered to the nonwoven fabric on the back surface of the absorbent article as in the technique shown in FIG. The adhesive sheet between the non-woven fabric and the pressure-sensitive adhesive is weakened due to a decrease in temperature or the surface of the non-woven fabric being rough and unable to form a uniform adhesive layer on the surface. At this time, there is a problem that the adhesive remains on the release sheet.

  On the other hand, in order to strengthen the adhesive force between the nonwoven fabric and the pressure-sensitive adhesive, when the adhesive is lowered and the adhesive penetrates the nonwoven fabric, when the absorbent article is peeled from the underwear after use, There is a problem that the non-woven fabric breaks and adhesive or the like remains in the underwear.

    On the other hand, in the prior art described in Patent Document 1, there is a method in which each adhesive surface of the double-sided tape is used separately for an adhesive surface with an undergarment and an adhesive surface with an absorbent article. Is additionally required, and at the same time, a separate substrate is required between the two adhesive layers, which is wasteful. In addition, in the product processing process, the pattern of the anti-slip material has to be simple, and there are restrictions in applying to the pattern for the purpose of preventing misalignment and improving misalignment.

  Therefore, the object of the present invention is to remove the adhesive sheet on the release sheet when peeling the individual sheet that has been subjected to the release treatment at the time of wearing, and when the absorbent article is peeled from the underwear after use, the nonwoven fabric breaks down and the underwear It is an object to provide an absorbent article production method that is optimal for adhering a non-woven fabric disposed on the back surface of an absorbent main body and a release sheet with an optimum adhesive strength that does not leave an adhesive or the like. .

The present invention is a method for producing an absorbent article by laminating a release sheet to the nonwoven fabric sheet of the absorbent main body having a nonwoven fabric sheet as the lowermost layer on the lower surface of the liquid-impermeable backsheet, A first step of applying an adhesive to the surface of the sheet to form an adhesive layer; a second step of laminating and integrating the non-woven fabric sheet coated with an adhesive on the one surface; and the adhesive layer and the A method of manufacturing an absorbent article, comprising: a third step of pressing and bonding the nonwoven fabric sheet to the adhesive layer by pressurizing and bonding the adhesive obtained by bonding the nonwoven fabric sheet and the back sheet. The above object is achieved by providing.
In the present application, the “lowermost layer” of the absorbent main body refers to a layer that directly contacts the underwear when the absorbent main body is attached to the underwear, and “one side” of the nonwoven fabric sheet faces the back sheet. The “other surface” of the nonwoven fabric sheet refers to the surface that directly contacts the undergarment.

  According to the present invention, the pressure-sensitive adhesive layer formed on the release-treated individual sheet ensures the fixing force to the underwear so that the nonwoven fabric sheet does not break, and the adhesive layer formed on the nonwoven fabric sheet allows the adhesive to be applied to the nonwoven fabric sheet. It becomes possible to ensure adhesive strength. And, when joining the release treatment individual packaging sheet and the nonwoven fabric sheet, by integrating such an adhesive layer and adhesive layer, the adhesive force between the nonwoven fabric sheet and the adhesive layer, and the underwear and the adhesive layer As a result, it is possible to prevent the adhesive sheet from remaining on the release sheet or the undergarment, or the nonwoven fabric sheet from being destroyed.

Hereinafter, the most preferable embodiment of the manufacturing method of the absorbent article of this invention is described in detail.
As shown in FIG. 1 or FIG. 2, the method for manufacturing an absorbent article according to the present embodiment includes a nonwoven fabric sheet 3 of an absorbent main body 2 having a nonwoven fabric sheet 3 as a lowermost layer on the lower surface of a liquid-impermeable backsheet 6. Is a method of bonding the release sheet 7, and includes first to third steps described in detail below.

  The absorbent article 1 which is the target of the manufacturing method of the present embodiment is the absorbent main body 2 in which the back sheet 6 and the nonwoven fabric sheet 3 are arranged on the back side, and the nonwoven fabric sheet 3 is located in the lowermost layer, and the release sheet 7. In the case of this embodiment, as shown in FIG. 1, for example, the absorbent article 1 that is a sanitary napkin is the object of manufacture.

  The absorbent main body 2 includes a liquid-permeable top sheet 4 and a liquid-retaining absorbent 5 in addition to the back sheet 6 and the nonwoven fabric sheet 3. The top sheet 4 covers the surface of the absorbent body 5 and is folded back to the back side at both sides of the absorbent body 5 and joined to the back sheet 6 at the folded portion. For joining the top sheet 4 and the back sheet 6, a heat seal or a hot melt adhesive is used.

  On the other hand, the release sheet 7 is made of a resin film and has a function of wrapping the folded absorbent main body 2 as well as a slip-preventing adhesive (hereinafter simply referred to as “adhesive”) for fixing the absorbent main body 2 to the underwear. It is a sheet having a function of covering and protecting 12). The inner surface of the release sheet 7 is subjected to a release process so that the adhesive 12 does not adhere.

  As shown in FIG. 2, in the second step of the manufacturing method of the present embodiment, the first joining device 40 and the second joining device 50 on the production line (in-line) of the absorbent main body 2 are used. Here, this production line manufactures the absorbent main body continuous sheet 2A in which these are joined from the top sheet raw fabric 4A, the absorbent body 5, the back sheet raw fabric 6A, and the nonwoven fabric sheet raw fabric 3A. The absorbent main body 2 is formed by cutting the sheet 2A.

The first joining device 40 includes a joining roller pair 41, a first hot melt gun 42, and the like, and is installed in the step of joining the back sheet original fabric 6A to the top sheet original fabric 4A in which a plurality of absorbers 5 are arranged. Has been.
The second joining device 50 includes a joining roller pair 51, a second hot melt gun 52, and the like, and a step of joining the nonwoven fabric sheet original fabric 3A onto the back sheet original fabric 6A in the intermediate body 2B that has passed through the first joining device 40. It is installed in. The second hot melt gun 52 is configured to heat and pressurize the filled adhesive for exudation (hereinafter also simply referred to as “adhesive”) 11.

  As shown in FIG. 3, the reversing device 15 is used in the first and third steps of the manufacturing method of the present embodiment. The reversing device 15 includes a first reversing machine 20, a second reversing machine 30, a third hot melt gun 23, etc., and is a process after the process of the production line of the absorbent main body 2, and the absorbent main body 2. And in the process of bonding the release sheet 7 together.

  The first reversing machine 20 includes a first reversing roller 21, a pressure roller 22, and the like. The second reversing machine 30 includes a conveyance belt 31, a second reversing roller 32, and the like. The first and second reversing rollers 21 and 32 are arranged at positions close to each other, and the joined release sheet 7 and the absorbent main body 2 are joined and pressed together. Furthermore, the pressure roller 22 is adapted to add and release the release sheet 7 and the absorbent main body 2 as appropriate.

  The third hot melt gun 23 is configured to spray or coat the pressure-sensitive adhesive 12 that has been filled by heating and pressurizing, and is disposed at a position upstream of the first reverse roller 22.

Next, the manufacturing method of the absorbent article of this embodiment is demonstrated.
In the first step, first, the release sheet 7 is conveyed in the A direction (direction opposite to the conveyance line direction B) by the first reversing machine 20. In this case, the release sheet 7 is placed so that the release-treated surface becomes the upper surface. Next, the adhesive 12 is sprayed or applied to the surface of the release sheet 7 by the third hot melt gun 23 to form the adhesive layer 12A.

  In this case, as the adhesive 12, for example, styrene-butadiene-styrene (SBS), styrene-ethylene-butadiene-styrene (SEBS), styrene-isoprene-styrene (SIS), or the like is used. It is preferable that the heating temperature of the adhesive 12 is 120-170 degreeC from the applicability | paintability to a peeling sheet and a damage reduction viewpoint. Within this temperature range, it is easy to keep the hot melt pattern to be applied stable and to easily keep the bonding temperature at the junction. Moreover, it becomes easy to use a material having a low melting point as a release sheet.

  The adhesive force of the pressure-sensitive adhesive 12 is preferably lower than that of a normal case from the viewpoint that it is important that the nonwoven fabric sheet 3 is not destroyed during use, and specifically, 5 to 20 N / 25 mm. Preferably there is. When the adhesive strength is within the range, the product is stably attached to the underwear or the like during use, and the product is easily peeled off from the underwear after use. More specifically, it is possible to effectively prevent the product from falling off the underwear or the like during use, or the product from being displaced during use, and when the absorbent article 2 is peeled from the underwear after use, the nonwoven sheet 3 It is prevented from being destroyed. For example, a spiral spray, a multi-row bead, a slot spray, a slot coater, or the like is used for the coating method of the adhesive 12. In particular, the slot coater is preferable from the viewpoint that the adhesive surface is clear and the adhesion is stable. . The thickness of the adhesive layer 12A is preferably 20 to 70 μm.

On the other hand, the second step proceeds independently of the first step in advance of the first step. In the second step, first, the intermediate body 2B that has passed through the first joining device 40 is transferred to the second joining device 50. To pass through. In the second joining device 50, the exuding adhesive 11 sprayed from the second hot melt gun 52 is applied to the nonwoven fabric sheet original 3A. Thereafter, the nonwoven fabric sheet material 3A is bonded to the back sheet material 6A of the intermediate body 2B by the joining roller pair 51. (See FIG. 1).

  In this case, a plurality of apertures (not shown) are formed in the nonwoven fabric raw sheet 3A, and the exuding adhesive 11 is positively exuded from the apertures during the pressurization in the next third step. To. The pattern of the openings is arranged according to the pattern of the adhesive layer 12A formed on the release sheet 7 in the first step, and the adhesive layer 11A is opposed to the adhesive layer 12A. Of course, this opening may be formed in advance.

The coating amount of the exuding adhesive 11 is 3 to 20 g / m ² from the viewpoint of not only adhering the back sheet original fabric 6A and the nonwoven fabric sheet original fabric 3A but also exuding an effective amount from the nonwoven fabric sheet original fabric 3A. Preferably there is.

The exuding adhesive 11 may be the same rubber-based adhesive as the anti-displacement pressure-sensitive adhesive 12, but a hot-melt adhesive having a low cohesive force and being easily absorbed into the nonwoven fabric fiber and having good dispersibility is preferable. For example, olefinic hot melt is preferable. The heating temperature of the exuding adhesive 11 is preferably equal to or higher than the heating temperature of the shift preventing adhesive 12 from the same viewpoint as in the first step.
The adhesive strength of the exuding adhesive 11 is lower than usual in consideration of prevention of breakage of the nonwoven fabric during use and adhesiveness to the underwear in the same manner as in the first step. It is preferable to be equal to the adhesive force of the agent 12, and it is more preferable that the adhesive force during the processing of the product is strong, but the adhesive force during use of the product is low. And it is preferable that the adhesive force of such an adhesive has the largest part joined to 12 A of adhesion layers. Specifically, an olefin-based adhesive having a long open time, that is, a viscosity increase rate during processing is slow and adhesive force during processing is high, and the adhesive force greatly decreases with time after processing is used. A method is mentioned. As with the first step, spiral spray and slot spray are used for the application method of the exuding adhesive.

  Then, in a 2nd process, the absorptive main body continuous sheet 2A which passed through the 1st joining apparatus 50 is cut | disconnected, the absorptive main body 2 is formed, and this absorptive main body 2 is sent to the 2nd inversion machine 30 one by one.

In the third step, the release sheet 7 that has undergone the first step and the absorbent main body 2 that has undergone the second step are merged between the first and second reversing rollers 21 and 32, and under a certain pressure, The adhesive layer 12A and the adhesive layer 11A are joined and fused together, and the release sheet 7 and the nonwoven fabric sheet 3 of the absorbent main body 2 are bonded together.
In this case, the adhesive layer 12 </ b> A and the adhesive layer 11 </ b> A are in a molten state at their respective heating temperatures, and become an integrated adhesive layer 13 when pressed. Here, when the first and second reversing rollers 21 and 32 are provided with a heating function, when the adhesive layer 12A and the adhesive layer 11A are fused, they may be reheated, or when the adhesion is insufficient. The adhesive force can be adjusted by the pressure roller 22. The thickness of the pressure-sensitive adhesive layer 13 is 10 μm or more, particularly 15 μm or more, and preferably 90 μm or less, particularly 70 μm or less. The thickness can be controlled by the pressure between the pressure rollers 21 and 32 or the pressure between the pressure rollers 21 and 22.

  After the third step, the absorbent article 1 in which the release sheet 7 is bonded to the absorbent main body 2 is conveyed by the first reverse roller 22 in the direction B while being turned upside down and sent to the subsequent packaging step.

  As described above, according to this embodiment, the pressure-sensitive adhesive 12 is applied to the surface of the release sheet 7 to form the pressure-sensitive adhesive layer 12 </ b> A, and the surface of the nonwoven fabric sheet 3 is leached and bonded by the bleed-out adhesive 11. Since the layer 11A is formed, the adhesive layer 12A ensures adhesion to the underwear to such an extent that the nonwoven fabric sheet 3 does not break, and the adhesive layer 11A leached onto the nonwoven fabric surface adheres the adhesive to the nonwoven fabric sheet 3. It becomes possible to secure power.

  And when joining the peeling sheet 7 and the nonwoven fabric sheet 3, the adhesive force between the nonwoven fabric sheet 3 and the adhesion layer 13 by making such an adhesion layer 12A and the adhesion layer 11A into the integral adhesion layer 13 is used. And, the adhesive force between the underwear and the pressure-sensitive adhesive layer 13 can be optimized, and as a result, it is possible to prevent the adhesive sheet from remaining on the release sheet 7 and the underwear, or the nonwoven fabric sheet 3 from being destroyed. be able to.

  Moreover, according to this embodiment, since the opening for exudation was formed in the nonwoven fabric sheet 3, the adhesive 11 for exudation can be actively exuded to the nonwoven fabric sheet 3 from this opening. In particular, since the hole pattern is arranged according to the pattern of the adhesive layer 12A of the release sheet 7, the adhesive layer 11A can be bonded to the adhesive layer 12A without fail. Such an opening is particularly effective in forming the adhesive layer 11A when using a nonwoven fabric with a high basis weight to give a soft texture to the absorbent article.

The present invention is not limited to the above-described embodiment, and various changes can be made.
The production method of the present invention is not limited to absorbent articles such as sanitary napkins and disposable diapers, and can be widely applied to techniques for bonding a release sheet and a nonwoven fabric.
The manufacturing method of the present invention is preferably carried out using the first and second joining devices in the second step and using the first and second reversing machines in the first and third steps. Even without using such a joining device or reversing machine, a pressure-sensitive adhesive is applied to the surface of the release sheet in the first step to form a pressure-sensitive adhesive layer, and in the second step, the nonwoven fabric sheet and the backsheet are bonded with an adhesive, In the third step, the pressure-bonding of the pressure-sensitive adhesive layer and the non-woven fabric sheet, and the pressure-bonding adhesive that bonds the non-woven fabric sheet and the back sheet to the pressure-sensitive adhesive layer for bonding to the pressure-sensitive adhesive layer. That's fine.

In the above embodiment, the adhesive strength of the adhesive and the adhesive strength of the adhesive were measured by the following “adhesive strength test method”.
<Adhesion test method>
A melted adhesive (or pressure-sensitive adhesive) was applied to a polyethylene film with a thickness of 50 μm and a width of 100 mm, and left for 24 hours. Then, this film was cut according to a 150 × 25 mm stainless steel plate, reciprocated once with a 2 kg rubber roll, and left at a temperature of 20 ± 2 ° C. for 30 minutes. Then, when this film is reversed 180 ° and peeled off, the tensile force is measured. This is repeated 5 times, and the average value of each measured value is defined as the adhesive strength of the adhesive (or adhesive).
Here, a Tensilon tensile tester (manufactured by Orientec Co., Ltd.) was used for measuring the tensile force. The speed of the rubber roll was 300 mm / min at a temperature of 20 ± 2 ° C.

It is sectional drawing which shows schematic structure of the absorbent article manufactured by the manufacturing method of this embodiment. It is a figure which shows the one part schematic structure of the manufacturing apparatus used for the manufacturing method of this embodiment. It is a figure which shows schematic structure of the inversion apparatus used for the manufacturing method of this embodiment. It is a figure which shows schematic structure of the inversion apparatus used for the conventional manufacturing method.

Explanation of symbols

2 Absorbent body 3 Non-woven sheet 7 Release sheet 11 Exuding adhesive (adhesive)
11A Adhesive layer 12 Misalignment preventive agent (adhesive)
12A adhesive layer

Claims (6)

A method for producing an absorbent article by laminating a release sheet to the nonwoven fabric sheet of the absorbent main body comprising a nonwoven fabric sheet as a lowermost layer on the lower surface of a liquid-impermeable backsheet,
A first step of applying an adhesive to the surface of the release sheet to form an adhesive layer;
A second step of laminating and integrating the non-woven sheet coated with an adhesive on one surface to the back sheet;
Said adhesive layer and said nonwoven sheet by pressure bonding, in which said nonwoven fabric sheet and the adhesive bonds the said back sheet is exuded by pressure bonding with the adhesive layer, and a third step The manufacturing method of the absorbent article containing.   2. The method for manufacturing an absorbent article according to claim 1, wherein in the second step, the nonwoven fabric sheet having an opening is used and the adhesive layer leached from the opening is joined to the adhesive layer.   The manufacturing method of the absorbent article of Claim 2 which arrange | positions the said hole of the said nonwoven fabric sheet corresponding to the area | region which the said adhesion layer of the said peeling sheet occupies in the said 2nd process.   The manufacturing method of the absorbent article in any one of Claims 1-3 which makes the adhesive force of the said adhesive used at a said 1st process 5-20N / 25mm. Wherein in the second step, the coating amount of the adhesive of the portion to be joined to at least said adhesive layer, the manufacturing method of an absorbent article according to any one of claims 1 to 4 to 3 to 20 g / m ^2.   The absorbent article according to any one of claims 1 to 5, wherein in the second step, at least two or more kinds of the adhesives are used, and the adhesive force of the adhesive at a portion to be bonded to the adhesive layer is maximized. Manufacturing method.

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