JP2801618B2 - Surface material for absorbent articles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention generally relates to an absorbent article such as a sanitary article which is in close contact with a body and absorbs and retains excrement including liquid from the body. It is related to surface materials. More specifically, the present invention relates to a surface material suitably used for sanitary napkins and the like.

[Problems to be solved by conventional technology and invention]

Sanitary products used to absorb and retain bodily exudates, including liquids from the body, are absorbents that absorb and retain bodily exudates, liquid-impermeable leakproof materials, and bodily exudates that come into direct contact with the body. It is well known to be composed of a transparent surface material.

Efforts have been made to increase the absorption and / or retention of the absorbent body in order to increase the effectiveness of the sanitary article, and significant progress has been made. While only fluff pulp is used as the absorbent, it is now common practice to add a highly absorbent polymer to fluff pulp to improve its absorbency. However, this absorbent cannot exert its effect unless the excrement can be effectively moved to the absorbent, so that the performance of the sanitary article as a whole deteriorates.

Therefore, as a function as a surface material, it is a matter of course that excrement is promptly transferred to the absorber (hereinafter, referred to as liquid permeability), and further, the liquid transferred to the absorber is subjected to pressure, An important function is to prevent the body from returning to the body side even if it overflows from the absorber (hereinafter, this is referred to as liquid return prevention). In particular, in a sanitary napkin in which the excreted liquid is menstrual blood containing a highly viscous liquid, liquid permeability is an important function.

Further, in the case of sanitary products, in addition to the reliability of the hard function of absorbing and holding the liquid, the comfort of the psychologically soft function is also a major factor. Psychological comfort often depends on the surface material that comes into direct contact with the body, in addition to the soft and gentle texture, the dryness after use on the surface material, that is, the amount of residual menstrual blood on the surface is small, Perceptual factors such as cleanliness after use due to the invisible color of menstrual blood transferred to the absorber are important factors.

Only with these hard and soft functions is a sanitary product desired by women. To achieve this goal,
Various proposals have been made, and there are many improvements.

Specifically, first, a non-woven fabric, which is an aggregate of hydrophobic fine fibers, is used as a surface material to form a space in a hydrophobic atmosphere between the body surface and the absorber, thereby returning the liquid without impairing the liquid permeability. A technique for improving the prevention (JP-A-58-180602) can be mentioned. However, in a nonwoven fabric, the liquid to be transferred to the absorber is easily retained in a minute space that is inevitably formed as an aggregate of fibers, and when pressure is applied, the retained liquid is easily transferred to the body surface. Because of the drawbacks, no matter how hydrophobic fibers are used, there is naturally a limit in improving the liquid return prevention. Furthermore, although the fine fiber aggregate has a soft texture, the dryness after use due to the retention of liquid in a minute space is not necessarily improved.

On the other hand, a technology to improve the liquid return prevention by using a hydrophobic sheet with openings as a surface material
54-124398, JP-A-57-1340 and JP-A-61-45753) have also been proposed.

Certainly, if the effective hydrophobic sheet is used as the surface material,
No liquid retention in the facing material occurs.

However, because of the hydrophobic film, it is necessary to make an opening in the film for the free passage of liquid and make the opening area large, and it is not always possible to prevent the liquid from returning to the body side due to the application of pressure. However, the ability to block menstrual blood after use, that is, dryness, is hardly desirable.

Furthermore, in the case of a hydrophobic apertured sheet, the area on the side in contact with the body increases, and the feeling of contact with the body is not always good, and even after use, menstrual blood tends to remain on the surface and dryness after use is low. Not always satisfactory. In order to solve this problem, an improved technique of embossing the surface of the film to provide irregularities (Japanese Patent Application Laid-Open No. 56-9401) and an improved technique of forming the opening portion with a tapered capillary structure (Japanese Patent Publication No. 57-17081) Has been proposed but is still insufficient.

There is a conflicting relationship between liquid permeability and dryness after use, that is, the ability to prevent liquid return, and if you add even a gentle texture, there are no surface materials that are satisfactory at present, and it is worth the user as soon as possible. The appearance of a textured surface material is desired.

[Means for solving the problem]

The present inventors have conducted intensive studies to overcome such problems, and as a result, the presence of an oil component having a lower surface tension than menstrual blood on the surface of a liquid-permeable sheet made of a hydrophobic material, It has been found that a surface material that is excellent in feel, dryness after use, liquid permeability and liquid return prevention, and has a good texture and can be suitably used for sanitary goods, in particular, sanitary goods can be obtained. Was.

That is, the present invention is a liquid permeable sheet formed by perforating a fiber assembly in which an opaque hydrophobic film is laminated, and has a molecular weight of 10,000 or less and a temperature of 25 ° C. The present invention provides a surface material of an absorbent article, characterized by containing an oil component having a surface tension of 50 dyn / cm or less.

In the surface material of the present invention, an oil component having a molecular weight of 10,000 or less and a surface tension at a temperature of 25 ° C. of 50 dyn / cm or less is present on the surface of the hydrophobic liquid-permeable sheet that is in contact with the skin. Is a mandatory requirement.

The hydrophobic liquid-permeable sheet used for the surface material of the present invention is obtained by perforating a fiber assembly in which an opaque hydrophobic film is laminated, and preferably has a discontinuous perforated portion in a planar state. This is an opaque sheet having a discontinuous liquid-permeable space, such as a fiber assembly obtained by laminating an opaque hydrophobic film.

In a film or net itself in which a specific aperture is provided in a liquid-impermeable hydrophobic film, it is necessary to increase the aperture area for the free passage of liquid because of the hydrophobic film. Although the effect of preventing the liquid overflowing from the absorber from the part from returning to the opposite direction, that is, to the body direction, is weak, but the oil component having a lower surface tension than menstrual blood is present on the surface after use, the surface of the absorbent will be used. The remaining liquid amount is reduced, the dryness after use can be significantly improved, and comfort can be provided to the user.

In the present invention, as the shape of the opening of the hydrophobic film, preferably, the opening proposed in Japanese Patent Publication No. Sho 57-17081 and JP-A-55-32581 is a hydrophobic film having a tapered capillary structure. More preferably, the film is made of an opaque hydrophobic film having a top, a bottom, and a wall connecting them, and at least a part of the wall is provided with an opening, and an opening is formed on the bottom. The film has no holes. This is preferably used since it has a small opening area per se when viewed from the surface after use, and therefore has excellent shielding properties and excellent liquid return prevention properties.

In the present invention, the most preferably used hydrophobic liquid permeable sheet has a hydrophobic film layer on the side in contact with the skin and has a hydrophilic film on the side facing the absorber side due to menstrual absorption. A liquid permeable sheet comprising two layers of a fiber assembly, wherein the two layers are integrated, wherein the film layer comprises an opaque hydrophobic resin having a top, a bottom and a wall connecting them. The liquid permeable sheet is provided with an opening in at least a part of the wall and having no opening in the bottom.

In the present invention, the aperture of the film layer is free in a range of a desired balance by the liquid permeability and the liquid return preventing property, the shielding property after use of menstrual blood and the amount of liquid remaining on the surface, that is, the surface tension of the oily component. In general, the size of the holes is 0.1 to ² mm2, and the density of the holes is 1
It is preferably from 0 to 100 / cm ² .

In the present invention, the film layer is preferably opaque in order to impart sufficient shielding properties to the surface material. If the film layer is opaque, the surface material of the present invention becomes opaque and can be preferably used as a surface material of an absorbent article that absorbs a colored liquid such as menstrual blood. The opacity of this surface material is quantified as whiteness, and the whiteness is preferably 10% or more. Note that various methods can be considered as a method for giving opacity. For example, a method of adding a white pigment to a resin in a film manufacturing process, a method of applying a white pigment to a film surface by mixing an appropriate binder with a binder, and the like can be mentioned. Not limited to this, any method may be used.

As the resin forming the film layer, any resin may be used as long as it is hydrophobic. Examples include polyolefins, copolymer resins of olefins with other monomers (vinyl acetate, ethyl acrylate, etc.), synthetic resins such as polyester, nylon and acetate, and blended polymers of these. In consideration of the above, polyolefins, copolymer resins of olefins and other monomers or blended polymers thereof are preferable, and among them, low-density polyethylene, linear low-density polyethylene or ethylene-vinyl acetate copolymer or a blend thereof is more preferable. .

The surface material of the present invention is required to be such a hydrophobic liquid-permeable sheet, and to have an oil component having a molecular weight of 10,000 or less and a surface tension of 25 dyn / cm or less at 25 ° C. on the surface thereof. And Due to the presence of the oil component having a principal surface tension of 50 dyn / cm or less, menstrual blood present on the sheet surface can easily move to the opening at a small angle with respect to the sheet surface and the horizontal plane, and furthermore, the sheet surface In addition, menstrual blood itself is unlikely to remain, enabling the user to spend comfortably.

The oil component used in the present invention may be liquid, semi-solid, or solid, but considering that it can effectively act on the entire surface with a small amount, it is liquid to semi-solid at body temperature, that is, 36.5 ° C. Is preferred. The molecular weight needs to be 10,000 or less, preferably 7000 or less, more preferably 1,000 or less.

Specific examples of the oil component include silicone oils such as dimethylpolysiloxane and methylphenylpolysiloxane having high water repellency, fluorine compounds such as trifluorohexylpropionate, and higher alcohols such as oleyl alcohol, cetyl alcohol and lauryl alcohol. ,
Higher fatty acids such as capric acid and caproic acid, higher fatty acid esters such as 2-ethylhexanoic acid triglyceride, cetyl 2-ethylhexanoate, octyl laurate, and triethylolpropane tristearate, and hydrocarbons such as liquid paraffin and octene ,olive oil,
Examples include natural ester oils such as castor oil and natural waxes such as lanolin.

Particularly preferred oil components are water-repellent silicone oils and higher fatty acid esters represented by 2-ethylhexanoic acid triglyceride because of their odor and their stability over time.

As for the amount of the oil component present on the surface of the hydrophobic liquid permeable sheet, the presence of a large amount of the oil component adheres to the user's body and is not preferable as a tactile sensation. Does not appear. The amount present in the sheet surface varies depending on the kind of oil, preferably from ^{0.1g / m 2 ~10.0g / m 2} , more preferably from ^{0.3g / m 2 ~3.0g / m 2} .

In the present invention, in order to further improve the feeling of the body, it is also preferable to apply an embossing treatment or the like to a hydrophobic liquid-permeable sheet and then to make an oily component exist.

In the present invention, as a method of causing the oil component to be present on the surface, a method of applying the oil component to the side of the hydrophobic liquid-permeable sheet surface in contact with the user's body using a known technique such as a gravure coater or spraying is used. Another method is to knead the resin into a liquid-permeable sheet in advance, bleed it out, and bleed it out to the surface of the sheet. preferable.

〔Example〕

Hereinafter, the present invention will be described in more detail by examples,
The present invention is not limited to these examples.

Examples 1 to 7 and Comparative Examples 1 to 5 By adhering the oil components shown in Table 1 to a predetermined base material shown below using a predetermined method shown below in a predetermined amount shown in Table 1, Various surface materials were produced. Then, the surface material of a commercially available napkin "Lorrier" (manufactured by Kao Corporation) was removed, and each surface material was formed instead, and this was used as a napkin assumed sample.

The obtained napkin assumed sample was evaluated by the following method. The results are shown in Table 1.

<Base> Laminated film-1: As shown in FIG. 1, a film produced by laminating a low-density polyethylene film 1 on an olefin-based heat-bonded nonwoven fabric 2 and forming openings 3 therein.

Laminate film-2: After laminating a low-density polyethylene film on an olefin-based heat-bonded nonwoven fabric, emboss a fine pattern, and give microprojections with a height and spacing of about 10 μm each. A film produced by forming apertures of

Net: manufactured by slitting low-density polyethylene film and stretching.

Non-woven fabric: Manufactured by subjecting a web composed of polyethylene / polyester composite fibers to a hot air treatment.

<Adhesion Method> A: A predetermined oil component was applied to the film side surface of the laminate film, or the surface of the net or nonwoven fabric using a gravure coater.

B: At the time of producing a laminated film, a predetermined oil component was added to the film raw material resin.

<Evaluation method> (1) Return amount 10 g of a red test liquid was injected into a napkin assumed sample, pressurized after a certain period of time, and the amount of the test liquid returning through the surface material was defined as a return amount.

(2) Detergency The surface condition of the napkin assumed sample after measurement of the return amount was classified into the following five ranks.

Grade 5: No red color of the test solution was observed.

Grade 4: Very little red color of the test solution is observed.

Grade 3: Some red color of the test solution is observed.

Second grade: The red color of the test liquid is partially noticeable.

First grade: The red color of the test solution is remarkably observed over the entire surface.

[Effects of the Invention] As can be seen from Examples 1 to 7, the surface material according to the present invention is excellent in liquid return prevention and cleanliness. Three types of substrates, a laminate film, a net, and a non-woven fabric, have been tested. As can be seen from the evaluation results, the effect is most remarkable in the case of the example of the present invention using the laminate film, The net of No. 2 is slightly inferior, and the nonwoven fabric of Comparative Example 1 is considerably inferior. The effect of Example 5 using the laminated film-2 having minute projections was extremely remarkable, indicating that the above-mentioned performance was dramatically improved by the synergistic effect of the surface morphology of the base material and the adhesion of the oil component. ing.

On the other hand, in Comparative Examples 3 to 5, since the substrate to which the oil component did not adhere was used as the surface material as it was, the liquid return prevention property and the cleanability were poor, and all were extremely insufficient as the surface material. I have to say that there is.

[Brief description of the drawings]

FIG. 1 shows a laminate film used in an embodiment of the present invention.
1 is a perspective view of FIG. 1: Low density polyethylene film 2: Olefin heat-bonded nonwoven fabric 3: Opening

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshihiro Sakai 420-57 Hiramatsucho, Utsunomiya City, Tochigi Prefecture Townhouse Matsumi C-202 (72) Inventor Takatoshi Kobayashi 3009-1 Imaizumicho, Utsunomiya City, Tochigi Prefecture (56) Reference Document JP-A-63-51857 (JP, A) JP-A-47-25481 (JP, A) JP-A-62-276002 (JP, A) JP-A-63-49158 (JP, A) JP-A-2- 216265 (JP, A) Japanese Utility Model 60-135115 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) A61F 13/15

Claims (1)

(57) [Claims] 1. A liquid permeable sheet formed by perforating a fiber assembly laminated with an opaque hydrophobic film,
25 ° C with a molecular weight of 10,000 or less on the hydrophobic film side surface
A surface material for an absorbent article, characterized by the presence of an oil component having a surface tension of 50 dyn / cm or less at a temperature of the above.