JP2008142206A - Absorbent articles - Google Patents

Abstract

Disclosed is an absorbent article capable of preventing unpleasant noise from being produced during attachment or removal, and preventing clothing-facing surfaces from sticking to each other or from sticking to the hand. .
A large number of fine protrusions 13 made of a thermoplastic material containing a filler are formed on the garment facing surface of an absorbent article 10. It is preferable that the microprotrusions 13 are arranged in a scattered manner on the clothing facing surface. It is also preferable that the fine protrusions 13 are formed by spraying a molten thermoplastic material containing a filler on the clothing facing surface.
[Selection] Figure 2

Description

  The present invention relates to absorbent articles such as sanitary napkins, panty liners, and incontinence pads.

  Conventionally, in absorbent articles such as sanitary napkins, panty liners (origami sheets), and incontinence pads, an adhesive layer is provided on the back sheet, and the absorbent article is fixed to clothing such as shorts via the adhesive layer. It is widely done. By fixing to shorts etc. via an adhesive layer, it can fix to an appropriate position easily and can prevent position shift during wearing. However, on the other hand, when an absorbent article is peeled from shorts, etc., a sound is generated, which may cause discomfort such as stress to a user who does not want others to notice the use or replacement of the absorbent article. . In addition, when attaching or removing the absorbent article, the back sheets may stick to each other or the back sheets may stick to the hand.

  Patent Document 1 discloses a technique for reducing sound when an absorbent article is peeled from an individual wearing sheet. In this technique, two types of hot melt adhesives are applied between an absorbent article and an individual sheet so as to allow delamination, and the hot melt adhesive closer to the absorbent article forms a slip prevention layer. Is. According to this technique, the sound when the absorbent article is peeled off from the individual wearing sheet is reduced, but the sound when the absorbent article is peeled off from the shorts cannot be reduced.

  Patent Document 2 describes that a high friction nonwoven fabric having a sliding friction resistance value of 70 g or more is disposed on the underwear contact surface side when the absorbent article is used. Although there is no special description in the document, it is considered that the sound when the absorbent article is peeled off from the shorts can be reduced. However, since this nonwoven fabric is made of a special core-sheath type composite fiber and is expensive, it is not economically advantageous to use this nonwoven fabric for absorbent articles that are disposable articles.

  Patent Document 3 describes an anti-slip sheet. The anti-slip sheet has a first coating layer made of a foam of a polymer binder and a heat-expandable polymer bead on the sheet surface, and a second coating layer made of a polymer on the first coating layer. The production of this slip resistant sheet requires a coating and drying facility for the first coating layer and the second coating layer. As a result, the manufacturing cost increases.

JP 2005-336638 A Japanese Utility Model Publication No. 5-28329 Japanese Patent Laid-Open No. 1-294031

  Therefore, the objective of this invention is providing the absorbent article which can eliminate the fault which the prior art mentioned above has.

  The present invention provides an absorbent article in which a large number of microprojections made of a thermoplastic material containing a filler are formed on the garment facing surface.

  According to the present invention, since the adhesiveness of the garment facing surface is reduced and the frictional force is increased at the same time, the absorbent article being worn is absorbed while preventing it from shifting from the appropriate position of the garment such as shorts. It is possible to effectively prevent an unpleasant sound when attaching or removing the property article, sticking the surfaces to each other, and sticking the surfaces to the hand.

  Hereinafter, the present invention will be described based on preferred embodiments thereof. The absorbent article of the present invention typically includes a top sheet, a back sheet, and a liquid-retaining absorbent body disposed between both sheets. The top sheet faces the wearer's body when the absorbent article is used. On the other hand, the back sheet faces clothing such as underwear. As the top sheet and the back sheet, materials usually used in the technical field can be used without particular limitation. For example, as the surface sheet, liquid permeable sheets such as various nonwoven fabrics and perforated films subjected to a hydrophilic treatment can be used. As the back sheet, a thermoplastic resin film, a laminate of the film and a nonwoven fabric, or the like can be used. The back sheet is generally liquid impermeable or water repellent. The back sheet may have water vapor permeability. The absorbent article may further include various members according to specific uses of the absorbent article. Such members are known to those skilled in the art. For example, when an absorbent article is applied to a sanitary napkin, a pair of three-dimensional guards can be arranged on both the left and right sides on the top sheet. This solid guard may be provided with an elastic thread at its free end in an extended state to further ensure the standing of the solid guard.

  FIG. 1 schematically shows a plan view of an embodiment of an absorbent article 10 of the present invention as viewed from the clothing facing surface, that is, from the outer surface side of the back sheet 11. The present embodiment relates to a sanitary napkin as an example of an absorbent article. On the outer surface of the back sheet 11 of the absorbent article 10, an application region 12 of the composition of the thermoplastic material is formed over almost the entire area.

  The composition of the thermoplastic material is used for the purpose of increasing the friction coefficient of the outer surface of the back sheet 11. In detail, the composition of a thermoplastic material is comprised including the filler and the thermoplastic material. A large number of minute protrusions made of a thermoplastic material containing a filler are formed on the outer surface of the back sheet 11.

  FIG. 2 schematically shows an enlarged main part of the absorbent article 10 of the present embodiment in a state where it is attached to clothing. In the same figure, the code | symbol T has shown the thread | yarn which comprises the cloth F of clothing. This fabric F shows a plain weave cloth. On the outer surface of the back sheet 11 facing and facing the fabric F, a large number of minute protrusions 13 made of the thermoplastic material containing the filler described above are formed. On the surface of the fabric F, there are minute convex portions and concave portions formed by yarns constituting the same. The microprojection 13 is in a state of being caught or caught between the convex portion and the concave portion. This biting or catching causes a frictional force between the back sheet 11 and the fabric F. This frictional force makes it difficult for the absorbent article 10 to be displaced in the lateral direction. It should be noted that FIG. 1 is a schematic diagram for facilitating understanding of the present invention, and the actual state is not drawn accurately. For example, the actual thickness of the thread T is preferably about 3 to 5 times the height of the microprojections 13. The actual yarn T is a twisted yarn.

  On the other hand, in the conventional absorbent article, since the hot melt adhesive is so-called solid-coated on the outer surface of the back sheet, the surface of the coating layer of the adhesive is almost flat. Therefore, it was difficult for the coating layer of the adhesive to bite into the irregularities on the surface of the underwear fabric. That is, the conventional absorbent article which has the application layer of a hot-melt-adhesive agent on the outer surface of a back surface sheet prevented the position shift using the adhesiveness which this adhesive agent has. In other words, the absorbent article did not prevent misalignment using frictional force.

  The microprotrusions 13 are scattered in the above-described application region 12. The scattered dot shape means not only a dot shape (dot shape) but also an elongated shape whose length with respect to the width is about several tens of times. In other words, the dot shape means that the minute protrusions 13 are dispersed and arranged independently independently of each other. Therefore, when the minute protrusions are substantially infinitely long and continuous, the minute protrusions are not said to be scattered.

  In order for the microprotrusions 13 to bite between the convex portions and the concave portions existing on the surface of the fabric F, the height of the microprotrusions 13 depends on the material of the fabric F and the weaving method, but is 30 to 200 μm. In particular, the thickness is preferably 50 to 150 μm. The height of the microprotrusions 13 is measured by cutting out a longitudinal section of the back sheet 11 of the absorbent article 10 and observing it with a microscope.

The same reason as described above, the microprojections 13, ² individual area 0.001～1Mm, it is preferable in particular 0.001-0.1 mm ^2, especially 0.001～0.05Mm ^2. The area of the microprojections 13 is measured by observing the outer surface of the back sheet 11 of the absorbent article 10 with a microscope.

  The total area of the microprotrusions 13 occupying the coating region 12, that is, the area ratio of the microprotrusions 13 is preferably 15 to 90%, particularly 20 to 80% from the viewpoint of preventing displacement.

From the viewpoint of misalignment prevention and microprojection formation, the application basis weight of the composition of the thermoplastic material in the application region 12 is preferably 3 to 50 g / m ² , particularly 5 to 20 g / m ² .

  The degree of the frictional force due to the fine protrusions 13 is preferably 400 gf or more, particularly 600 gf or more from the viewpoint of ensuring prevention of displacement of the absorbent article 10. This frictional force is measured according to the adhesive strength test (the first method) of the sanitary treatment product voluntary standard established by the Japan Sanitary Materials Industry Association. The specific test method is as follows.

[Method of measuring frictional force]
A piece of cotton cloth (80 mm × 200 mm) is stuck on the glass plate of the adhesion tester, and the temperature is adjusted to 30 to 31 ° C. in advance. The surface of the sample napkin on which the fine protrusions 13 are formed is placed flat on a piece of cotton cloth, and one end in the longitudinal direction of the napkin is sandwiched by a pulling clip. A pulling string is attached to the pulling clip. The pull string hangs down vertically through a pulley, and a weight is attached to the tip. Next, 750 g of affixing weight is placed almost at the center of the napkin, and the napkin is affixed to a piece of cotton cloth for 1 minute. After 1 minute, the pasting weight is removed, and instead, a pulling weight 225 g is placed on the napkin. Immediately after that, a pulling load of 230 g is attached to the pulling string and the napkin is pulled in the horizontal direction. When the napkin is not displaced within 1 minute, the tensile load is further increased by 20 g and the pulling is continued. The tensile load when the napkin is displaced within 1 minute is determined, and the value is taken as the adhesive strength. The measurement environment is 23 ° C.

  As described above, in the absorbent article 10 of the present embodiment, the microprojections 13 bite into the surface of the clothing fabric to generate a frictional force, and the frictional force prevents misalignment of the absorbent article 10. . Furthermore, in the absorbent article 10 of the present embodiment, unlike the conventional absorbent article having a hot melt adhesive coating layer on the outer surface of the back sheet, the coated region 12 composed of the fine protrusions 13 does not exhibit as much stickiness as possible. I am doing so. For this purpose, in the present embodiment, a filler is included in the thermoplastic material constituting the microprojections 13. The presence of this filler reduces the tackiness of the thermoplastic material itself. From this viewpoint, the filler content in the thermoplastic material containing the filler is preferably 15 to 50% by weight, and more preferably 25 to 49% by weight.

  The size of the filler is not critical in the present invention. The size of the filler is appropriately selected according to the size of the microprotrusions 13 and the diameter of a nozzle provided in an apparatus (this apparatus will be described later) used to form the microprotrusions 13. Generally, when the particle size of the filler is 0.1 to 10 μm, particularly 0.3 to 3 μm, the desired microprojections 13 can be successfully formed. The particle size of the filler is measured by a laser diffraction type particle size distribution analyzer (for example, Shimadzu SALD-1100).

  As the filler, those effective for reducing the tackiness of the thermoplastic material are used. Examples of such fillers include inorganic compounds and metal particles. Further, organic particles having a melting point or decomposition point higher than the melting point of the thermoplastic material can also be used. These fillers can be used alone or in combination of two or more. Particularly preferred fillers include, for example, calcium carbonate and talc particles.

  The filler may be exposed on the surface of the microprojection 13 or may be buried in the microprojection 13. In any case, the tackiness of the thermoplastic material is reduced.

  Examples of the thermoplastic material to which the filler is added include various thermoplastic resins such as polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, polyamide resins, acrylic resins, polyvinyl chloride resins, polystyrene resins, and various elastomers. Resin etc. are mentioned. These resins can be used alone or in combination of two or more. A particularly preferred thermoplastic material is a hot melt adhesive. Since the hot melt adhesive has a low viscosity at the time of melting, it is easy to uniformly disperse the filler, and it is easy to apply and transport inside the apparatus. In addition, it is easy to control the adhesiveness to optimize the applicability and fixability to the clothing facing surface. By using a hot-melt adhesive as the thermoplastic material and adopting the method described later, the fine protrusions 13 can be successfully formed.

  A hot melt adhesive is a composition containing a base polymer, a tackifier component that is solid at room temperature, a softener component, and the like. Base polymers include styrene butadiene rubber, styrene / butadiene / styrene block copolymer, styrene / isoprene / styrene block copolymer, styrene / ethylene / butylene / styrene block copolymer, and styrene / ethylene / propylene / styrene block copolymer. A polymer etc. are mentioned. The base polymer is preferably used in the range of 10 to 130 parts by weight, particularly 15 to 120 parts by weight, when the total amount of the tackifier component and the softener component is 100 parts by weight.

The tackifying component, C ₅ petroleum resins, C ₉ petroleum resins, dicyclopentadiene-based petroleum resins, rosin-based petroleum resins, polyterpene resins, terpene phenol resins, and the like, the total tackifying component and softening agent component It is preferably used in the range of 60 to 99 parts by weight, particularly 70 to 95 parts by weight in the amount of 100 parts by weight.

  Examples of the softener component include process oil having a softening point of 10 ° C. or less and an average molecular weight of 200 to 700, mineral oil, various plasticizers, polybutene, and liquid tackifier resin. The total of the tackifier component and the softener component It is preferably used in the range of 1 to 40 parts by weight, particularly 5 to 30 parts by weight in 100 parts by weight.

  In addition to the above-mentioned components, the hot melt adhesive may contain an antioxidant as necessary. As antioxidants, phenolic antioxidants, amine antioxidants, phosphorus antioxidants, benzimidazole antioxidants, etc. are used, and the total amount of base polymer, tackifier component and softener component is 100. When used as parts by weight, it is preferably used in the range of 0.5 to 3 parts by weight.

  In the absorbent article 10 of this embodiment, the usability of the absorbent article 10 is improved in the application region 12 of the thermoplastic material composition on the outer surface of the back sheet 11 and / or in the region outside the application region 12. As long as it does not worsen, an application layer of a hot-melt adhesive having adhesiveness may be formed. The reason for providing this coating layer is to prevent the absorbent article 10 from falling from the underwear when the coating layer is attached to and / or removed from the underwear of the absorbent article 10. Examples of the hot melt adhesive that can be used include the same hot melt adhesives that have been used in the technical field of absorbent articles as so-called slip-resistant adhesives. The application basis weight of the hot melt adhesive can be the same as that of the conventional absorbent article.

  Next, the manufacturing method of the absorbent article of this embodiment is demonstrated. The absorbent article of the present embodiment is formed by manufacturing the absorbent article including the topsheet, the backsheet and the absorbent body by the same method as the conventional method, and then forming the above-described micro protrusions 13 on the outer surface of the backsheet. Obtained by. For the formation of the microprojections 13, it is preferable to employ a method in which a molten thermoplastic material containing a filler is sprayed on the outer surface of the back sheet 11. When spraying a molten thermoplastic material containing a filler, it is preferable to spray the thermoplastic material by transporting it in a gas such as air. In this method, the thermoplastic material in a molten state is stretched during conveyance with gas, and is divided into fine short fibers or lumps due to fillers contained therein. And it adheres to the outer surface of the back surface sheet 11 with the state. As a result, the fine protrusions 13 distributed in the form of dots are successfully formed.

  Specific examples of the spraying method include a curtain spray method and a slot spray method.

  In addition, when the thermoplastic material which does not contain a filler is conveyed to gas and sprayed, the thermoplastic material in a molten state will be elongated elongated during conveyance by gas. As a result, on the outer surface of the back sheet, the thermoplastic material has a substantially continuous shape with an infinite length, and is not dispersedly arranged in the form of dots. Therefore, in order to successfully disperse and arrange the thermoplastic material in the form of scattered dots, it is important to both transport the molten thermoplastic material into a gas and spray it, and to include a filler in the thermoplastic material. It becomes.

  As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment. For example, in the above-described embodiment, means for spraying a molten thermoplastic material containing a filler is used to form the microprojections 13, but the method for forming the microprojections 13 is not limited thereto. For example, the fine protrusions 13 may be formed by various printing methods including a screen printing method.

  Moreover, although the said embodiment concerns the sanitary napkin, it is applicable also to other absorbent articles of this invention, for example, a panty liner, an incontinence pad, a breast milk pad, etc.

  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 sanitary napkin shown in FIG. 1 was produced. An air-through nonwoven fabric having a basis weight of 25 g / m ² was used as the top sheet. This non-woven fabric is composed of a core-sheath type composite fiber (fiber length 51 mm) whose core is polyethylene terephthalate and whose sheath is made of polyethylene. As the back sheet, a low density polyethylene film having a basis weight of 40 g / m ² was used. Further, as the absorbent body, a stacked fiber body (basis weight 243 g / m ² ) of fluff pulp and superabsorbent polymer particles was used. The length of the napkin was 225 mm.

After assembling a sanitary napkin using the above-described members by a conventional method, a composition comprising 30% calcium carbonate having a particle size of 1 μm and 70% hot melt adhesive is applied to the outer surface of the back sheet by a slot spray method ( A coating temperature of 150 ° C.), and a large number of fine protrusions were formed. As the hot melt adhesive, a rubber hot melt adhesive manufactured by NITTA FINDRE Co., Ltd. was used. The viscosity of the hot melt adhesive before mixing with calcium carbonate was 10000 mPa · s at the coating temperature. The application basis weight was 10 g / m ² . The area ratio of the microprojections was 25%. The height and area of the formed microprotrusions were determined by microscopic observation. The results are shown in Table 1 below.

[Comparative Example 1]
A sanitary napkin was obtained in the same manner as in Example 1 except that calcium carbonate was not added to the hot melt adhesive in Example 1. Due to the absence of calcium carbonate in the hot melt adhesive, the hot melt adhesive was applied to the outer surface of the back sheet in the form of a continuous line. That is, no microprojections were formed. The height and area of the hot melt adhesive applied to the outer surface of the back sheet were measured in the same manner as in Example 1. The results are shown in Table 1 below.

[Evaluation]
About the sanitary napkin obtained by the Example and the comparative example, the frictional force by the side of a back surface was measured by the above-mentioned method. Furthermore, the following method evaluated the adhesiveness by the side of a back surface, and the generation | occurrence | production degree of the peeling sound at the time of napkin removal. The results are shown in Table 1 below. The number of measurement samples was N = 2 in both Example 1 and Comparative Example 1.

〔Adhesiveness〕
Place the napkin on the kanakin cloth so that the back sheet is on the bottom. A load of 40 g / cm ² is applied to a range of 3 cm × 10 cm on the napkin. After storing for 12 hours in an environment of 35 ° C, turn the kanakin cloth upside down. At this time, if the napkin falls, it is determined that there is no adhesion, and if it does not fall, it is determined that there is adhesion.

[Degree of peeling noise]
A load is applied to the napkin placed on the Nakakin cloth in the same procedure as the above-described evaluation of adhesiveness. After storing for 12 hours, the sound when the napkin was peeled off from the kanakin cloth in a measurement environment of 23 ° C. was heard and the degree thereof was determined. The peeling speed of the napkin was approximately several tens of cm / second. In addition, since the napkin of the example did not have adhesiveness, it was peeled off simply by holding the napkin in the hand.

  As is apparent from the results shown in Table 1, it can be seen that the napkin of the example (product of the present invention) has a high frictional force on the outer surface on the back sheet side and no adhesiveness. It can also be seen that no peeling noise is generated when the napkin is removed. On the other hand, in the napkin of the comparative example, it can be seen that peeling sound is generated because the adhesiveness of the outer surface on the back sheet side is high.

It is the top view which looked at one Embodiment of the absorptive article of the present invention from the back sheet side. It is a schematic diagram which expands and shows the principal part in the state which attached the absorbent article shown in FIG. 1 to clothing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Absorbent article 11 Back surface sheet 12 Application | coating area | region of the thermoplastic material containing a filler 13 Microprotrusion F Fabric T

Claims (7)

  An absorbent article in which a large number of microprojections made of a thermoplastic material containing a filler are formed on a garment-facing surface.   The absorptive article according to claim 1 in which said fine projection is distributed and arranged in the shape of a dot on said clothing opposed surface.   The absorbent article according to claim 1 or 2, wherein the microprojections are formed by spraying the molten thermoplastic material containing the filler onto the clothing-facing surface.   The absorbent article according to any one of claims 1 to 3, wherein the thermoplastic material is a hot melt adhesive. The absorbent article according to any one of claims 1 to 4, wherein the minute protrusions have a height of 30 to 200 µm and an individual area of 0.001 to 1 mm ² .   The absorbent article according to any one of claims 1 to 5, wherein a content of the filler in the thermoplastic material containing the filler is 15 to 50% by weight.   The frictional force of the garment facing surface measured according to the adhesive strength test (first method) of the sanitary treatment product voluntary standard established by the Japan Sanitary Material Industries Federation is 400 gf or more. Absorbent article as described in 1.

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