HK1061963A - Dark colored absorbent articles - Google Patents

Description

Dark colored absorbent article

Technical Field

The present invention relates to dark colored (dark colored) disposable absorbent articles, particularly pantiliners (pantiliners) and sanitary napkins (sanitary napkins).

Absorbent articles according to the present invention have the benefit of being worn with dark colored undergarments (e.g., black, gray, navy blue, etc.) that are not apparent by visual inspection.

Background

Traditionally, absorbent articles, typically including diapers, adult incontinence products, underarm antiperspirant products (underslung products), collar inserts (collar inserts), sanitary napkins and pantiliners, have been provided in colors that convey hygiene. This has traditionally resulted in the use of white or predominantly white goods. This does fit well with the predominant undergarment color that is traditionally used to wear these articles, namely white undergarments. As a result, white pantiliners or white sanitary napkins are not readily identifiable when used in such white undergarments.

Fashion has made women more frequently use undergarments of other colors than white in recent years. This is not only determined by fashion itself, but is a result of the development of garments that have some transparency and make the color of the undergarment easily recognizable. Further, in recent years, so-called G-String underwear or tanka underwear ("Tanga-Slips") has been widely used, and is particularly favored by younger generation women. These so-called banded tanaka garments are particularly useful in preventing the contours of the undergarment from being readily discernable through a tight fitting garment.

Therefore, there is a need for a sanitary napkin or pantiliner that is color matched to the undergarment (and often the garment) to prevent the identification of the presence of such articles by color (assuming modern garments are transparent).

This is particularly important for sanitary napkins or pantiliners having so-called wings folded around the outside of the undergarment, since the wing portions of the sanitary napkin or pantiliner are intentionally folded over the outside of the undergarment and are therefore easily visible depending on the garment worn on the undergarment.

FI 9602361 to Anja Levoranta discloses a sanitary towel comprising an absorbent material and a backsheet (the side facing the garment), which towel is in accordance with the skin colour. The color may simulate a true skin color. DE 19821821 to Buetow Geb wantula discloses a pantiliner that can be divided into two tanga pantiliners along its diagonal. They are preferably produced in a plurality of different colors. In fact, the topsheet and backsheet of these pantiliners can be colored.

Traditionally, absorbent cores for use in absorbent articles such as pantiliners and/or sanitary napkins are available in white color to convey hygiene status. However, it has been observed that the use of such white absorbent cores in dark coloured absorbent articles provided with dark coloured so-called "apertured topsheets" conflicts with the discretion in the use of such articles, since the white colour is visible through the apertures of the dark coloured topsheet.

It is therefore an object of the present invention to provide absorbent articles, such as pantiliners and/or sanitary napkins, which are discreet to use when worn with dark colored undergarments. It is another object of the present invention to provide an absorbent article, in particular a sanitary napkin or a pantiliner, which is made such that when worn it is not easily recognizable on dark undergarments or more generally under clear garments, which is simple and inexpensive to produce on a large scale.

This problem is now solved by providing an absorbent article having an apertured topsheet, an underlying layer visible through the apertures of the topsheet, and a backsheet, wherein the topsheet and the underlying layer have an L Hunter value of less than 60. Preferably, the difference between the L Hunter values Δ L between the underlying layer (e.g., the secondary topsheet and/or the absorbent core) and the topsheet is less than 20.

Advantageously, the masking effect normally associated with absorbent cores having a light (white) color is provided, so that the absorbent core is not discernible through the apertures of the topsheet, thereby providing caution in the use of the overall absorbent article of the present invention. Masking the absorbent core in dark absorbent articles enhances discretion in use, especially at more intimate moments of women's life, where women may have to remove their undergarments.

Another in-use benefit associated with dark colored absorbent articles according to the present invention is the masking effect on body exudates absorbed and retained in the absorbent article. Body fluids such as vaginal secretions, enuresis and/or menses will be masked by the presence of underlying layers (e.g. secondary topsheet and/or absorbent core) having an L Hunter value of less than 60, preferably matching the color of the topsheet of the absorbent article of the present invention. This contributes to overall comfort and discretion. In fact, when the L Hunter value of both the topsheet and the underlying layer is less than 30 and preferably black, optimal masking of any bodily fluid discharges, especially menstrual blood discharges, entering the absorbent article is achieved.

In one embodiment of the present invention, the absorbent article of the present invention may comprise an odour control material such as activated carbon in its absorbent core, which is one of the most active and economical odour control materials. Traditionally, such odour control materials are not desirable for use in conventional sanitary white absorbent articles due to their inherent black colour. Activated carbon (also referred to as charcoal) may be advantageously used in dark colored absorbent articles of the present invention, particularly black colored absorbent articles, without compromising the comfort and discretion of the article.

Disclosure of Invention

The present invention includes an absorbent article comprising an apertured topsheet, an underlying layer visible through the apertures of the topsheet, and a backsheet, wherein the topsheet and the underlying layer each have an L Hunter value of less than 60 as defined by the Hunter Color system described below.

Description of the drawings

The invention is further described below with reference to the accompanying drawings.

Fig. 1 is a top view of a preferred black pantiliner according to the present invention with the topsheet facing the viewer (black/not shown color).

Fig. 2 is an enlarged transverse cross-sectional view of a pantiliner according to the present invention.

Fig. 3 is an enlarged transverse sectional view taken along line I-I of fig. 1.

Fig. 4 is an enlarged transverse cross-sectional view of another pantiliner according to the present invention.

Fig. 5 is a top view of another preferred black pantiliner according to the present invention, namely a thongpantiliner (thongpantiliner), with the topsheet facing the viewer.

Figure 6 is ｃA top view of ｃA black, striped pantiliner according to the present invention, the topsheet facing the viewer being provided with ｃA series of bond sites 1 where the topsheet is at least partially bonded to the underlying layers, in accordance with the teachings of EP- ｃA-617602 (dark/not shown color).

Detailed Description

Definition of

As used herein, "absorbent article" refers primarily to sanitary napkins, pantiliners, or incontinence pads worn in the crotch region of an undergarment. However, articles such as sweat absorbing underarm pads, nursing pads (nursing pads) or collar inserts can also benefit from the present invention. It is even further contemplated that infant diapers, adult incontinence diapers, and human waste management articles would benefit from the present invention even though they are not typically used with undergarments.

The term "disposable" is used herein to describe absorbent articles which are not intended to be laundered or otherwise restored or reused as an absorbent article (i.e., they are intended to be discarded after a single use and, preferably, to be recycled, composted or otherwise disposed of in an environmentally compatible manner).

Absorbent articles according to the present invention are generally composed of three main elements: a topsheet facing the user of the article during use and being liquid pervious for the passage of liquid into the article, the topsheet being an apertured topsheet; a backsheet providing a liquid containment function so that absorbed liquid does not leak through the article, the backsheet generally providing the garment-facing surface of the article; a layer underlying the apertured topsheet, said layer being visible through the apertures of the topsheet. The underlying layer is preferably provided by at least a portion of a secondary layer, also referred to herein as a secondary topsheet, and/or at least a portion of an absorbent core sandwiched between the topsheet and the backsheet and providing the absorbent capacity of the article to acquire and retain liquids that have entered the article through the topsheet. In some embodiments described below, the underlying layer may be provided by at least a portion of the backsheet and/or at least a portion of an intermediate layer disposed between the absorbent core and the backsheet.

Many absorbent articles and constructions, including specific materials, are well known in the art and have been described in great detail. All such materials can be used in the present invention as long as they meet the color requirements of the Hunter color coordinate values (color scale values) defined by the present invention. Typically this requires only modest modifications to the material composition while maintaining a major portion of the conventional material properties. Examples of materials mentioned hereinafter are particularly advantageous for use in the absorbent articles of the present invention. Alternative materials that may also be used in absorbent articles according to the present invention will be readily identified by those of ordinary skill in the art.

According to the present invention, the topsheet and the underlying layer of the absorbent article each have an L Hunter value of less than 60.

The L Hunter coordinate values used herein to define the depth (dark)/lightness (light) of the material of the absorbent article of the present invention are units of the measured Color of the Hunter Color system. A complete technical description of the system can be found in the article by R.S. Hunter, "photovoltaic color differential Meter", journal of the Optical Society of America, Vol.48, pages 985-95, 1958. A device specifically designed for measuring color based on Hunter coordinates is described in US3,003,388 issued to Hunter et al, 10 months and 10 days in 1961. In general, the Hunter color "L" coordinate value is the unit of measured light reflection, the higher the value, the lighter the color because lighter materials reflect more light. In particular, in the Hunter color system, the "L" coordinate contains 100 equal units, with absolute black at the bottom of the coordinate (L ═ 0) and absolute white at the top of the coordinate (L ═ 100). Thus, in measuring the Hunter color value of the material used in the absorbent article according to the present invention, the lower the "L" coordinate value, the deeper the material.

The absorbent articles of the present invention, as well as the materials used to make the absorbent articles, may be of any color so long as they meet the Hunter L value as defined herein.

As referred to herein, "color" includes any primary color, i.e., white, black, red, blue, violet, orange, yellow, green, and indigo, as well as any deviation thereof or mixtures thereof.

Color is measured according to a 3D solid diagram of internationally recognized colors in which all colors perceived by the human eye are converted into numerical codes. The system is based on three dimensions (x, y, z), in particular L^*，a^*And b^*。

When defining colors according to the system, L^*Represents luminance (0 ═ black, 100 ═ white), a^*And b^*Each independently representing two color axes, a^*Represents the axis red/green (+ a red, -a green), and b^*Represents axial yellow/blue (+ b ═ yellow, -b ═ blue).

Any color is identified by a unique Δ E value, which is represented by the following equation:

ΔE＝[(L^* _{reference to}-L^* _{Sample (I)})²+(a^* _{Reference to}-a^* _{Sample (I)})²+(b^* _{Reference to}-b^* _{Sample (I)})²]^1/2

Δ E graphically represents the reference color and the achromatic point of the 3d model (i.e., the center L of the sphere)^* _{Reference to}＝50，a^* _{Reference to}＝0，b^* _{Reference to}0) is measured.

Color was measured using a colorimeter MINOLTA model CR-300 instrument (available from Minolta Company, Japan) which provided the coordinate L^*，a^*And b^*And determining the Δ E value from these coordinates.

It should be understood that the Hunter L value and color value Δ E considered herein are measured on a material of interest (e.g., topsheet or backsheet or underlying layer) that is layered or folded upon itself such that the Hunter L value and color value remain constant when the same material is additionally layered or folded. In fact, the Hunter L value and Δ E are properties of the material itself, without any influence by the support in the instrument in which the material is arranged for material measurement. In other words, when measuring the Hunter L value of e.g. an apertured topsheet layer, several layers of the material are stacked or one layer is folded on itself several times before measuring its Hunter L value, the same material is measured again after another layering or folding, this latter operation being performed as necessary until the Hunter L value is no longer changed after additional layering or folding. This value is a value considered by the present invention.

Topsheet

An apertured topsheet (apertured topsheet) as defined herein refers to a topsheet having apertures. Apertured topsheets are generally compliant, flexible, soft feeling, and non-irritating to the wearer's skin.

The topsheet typically comprises a plurality of apertures having a pore size of 0.0001 to 5 mm. All holes may be of the same size or there may be holes of different sizes. The open area of the apertured topsheet is typically from 1% to 50%, preferably from 5% to 45%, more preferably from 10% to 40%, most preferably from 20% to 35%.

Apertured topsheets are typically apertured polymeric films. The pore-forming polymer thin films suitable for use in the present invention include pore-forming polymer-forming thin films, pore-forming thermoplastic thin films, pore-forming plastic thin films, and hydroformed thermoplastic thin films; a porous foam; reticulated foam; a reticulated thermoplastic film; and thermoplastic scrims (scrims).

Apertured formed films are particularly useful in the present invention as apertured topsheets because they can pass body exudates without absorbing them and have a reduced tendency to allow fluids to return and rewet the wearer's skin. Thus, the surface of the formed film that is in contact with the body remains dry; thereby reducing body soiling and providing a more comfortable feel to the wearer. Suitable shaped films are described in US3,929,135(Thompson), issued on 30/12 in 1975; U.S. Pat. No. 4,324,246(Mullane et al), granted on 4/13/1982; US4,342,314 (Radel et al), granted 8/3 in 1982; US4,463,045(Ahr et al), granted on month 7 and 31 of 1984; and US 5,006,394(Baird), entitled No. 4/9 1991. Particularly preferred micro-apertured formed film topsheets are disclosed in U.S. Pat. No. 4,609,518 issued on 9/2 1986 (Curro et al) and U.S. Pat. No. 4,629,643 issued on 12/16 1986 (Curro et al).

A formed film suitable for use herein is a black polyethylene voided formed film available from BPChemicals, Wasserburg-Germany under the code 45105/99 of Black CMP DH .

The body surface of the polymeric film topsheet may be hydrophilic to assist liquid in passing through the topsheet faster than if the body surface were not hydrophilic. In a preferred embodiment, surfactants are added to the polymeric material of the formed Film topsheet, such as PCT publication WO 93/09741 filed by Aziz et al on 19.11.1991, entitled "Absorbent apparatus Having A non-above and passing Film cover". Alternatively, the topsheet may be made hydrophilic by treating its body surface with a surfactant, as described in US4,950,254 referenced above.

Other apertured topsheets suitable for use in the present invention are made of woven or nonwoven materials or knitted (knit) materials. The material may be made from natural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g., polymeric fibers such as polyester, polypropylene, or polyethylene fibers), or from a combination of natural and synthetic fibers.

Apertured topsheets particularly suitable for use in the present invention are nonwoven topsheets. Suitable nonwoven materials/layers include fibrous nonwoven materials/layers formed by a carded, spunbond, or meltblown process in which a molten polymeric material is extruded through a die, attenuated to elongate the extruded polymer into fibers and reduce its diameter, and then deposited on a forming surface. Methods of forming such nonwoven materials/layers are known to those of ordinary skill in the art. Polymeric materials suitable for forming such fibrous nonwoven materials/layers include polyolefins such as polyethylene and polypropylene, polyesters, nylons, ethylene vinyl acetate, vinyl methacrylate, copolymers of the foregoing, block copolymers such as A-B-A block copolymers of styrene and butadiene, and the like.

A conventional nonwoven material suitable for use in the present invention is a black spunbond polyethylene layer available from BBA under the designation T27 CXC.

In addition to the conventional nonwoven materials described above, the apertured topsheet for use in the present invention may be made from conventional nonwoven materials which are generally provided by any of the methods mentioned above, such as spunbonding, and additional apertures are formed in the nonwoven material after the nonwoven material itself has been formed by any conventional method known to those of ordinary skill in the art for this purpose.

In another preferred embodiment of the present invention, the apertured topsheet comprises an apertured polymeric film, preferably an apertured formed film, and a nonwoven outer layer (nonwoven layer wearer facing surface). The nonwoven layer is typically disposed on the apertured polymeric film in a discontinuous manner such that at least the area where liquid is intended to be discharged onto the absorbent article is free of the nonwoven layer. In fact, it is particularly preferred that the topsheet is a so-called hybrid topsheet, wherein the longitudinal center of the wearer-contacting surface is provided with an apertured polymeric film, whereas the center not comprising this area is provided with a nonwoven such as a high loft nonwoven or other nonwoven which does provide a particularly skin friendly property (skinniness). Such topsheets are disclosed in EP-A-523683, EP-A-523719, EP-A-612233 or EP-A-766953. Fig. 1 shows a pantiliner 1 with a preferred topsheet comprising a nonwoven outer layer 2 and an apertured polymeric film layer 3 (apertures not shown). The nonwoven outer layer 2 has an opening 20 in the central region of the wearer facing surface of the absorbent article. The placement of the openings 20 in the nonwoven outer layer 2 serves as a conduit for the direct deposition of bodily waste onto the apertured formed film layer 3 to take advantage of its superior fluid handling properties so that fluid will more quickly enter the absorbent core. The nonwoven outer layer 2 typically comprises 2 strips 21, 22 spaced on top of the apertured formed layer 3 such that the spaced apart regions between the strips 21 and 22 form the openings 20. The two layers may be continuously, partially or intermittently bonded together. In a preferred embodiment, the nonwoven outer layer and apertured formed film layer are spot-bonded at multiple locations along the strips 21 and 22 with thermal bond blocks (heatbonds) 23. The thermo-stick block 23 provides an embossed sealing pattern, the pattern design of which may also provide aesthetic effects, such as wavy lines.

The apertured topsheet of the present invention can be made from a nonwoven or woven material or a polymeric film. Such films and nonwovens or wovens can be prepared, for example, from polymers such as polyethylene or polypropylene compositions. Such polymers have typically been provided with a coloring material, such as titanium dioxide, to provide white opacity. Simply using other colored materials (e.g., dyes, pigments, etc.), i.e., dark colored materials (e.g., black, navy blue, gray, etc.), provides a film or nonwoven having a dark color. However, the use of other coloring materials other than titanium dioxide to meet the L Hunter value of the material used in the present invention has the advantage of not causing any substantial material change. The special coloured fillers used in the material chosen for the manufacture of the top sheet also provide the additional benefit of better material properties (in addition to lower cost and reduced environmental load).

It is to be understood in the present invention that any conventional method known to one of ordinary skill in the art for providing a dark apertured topsheet (i.e., a material that meets the L Hunter value requirements of the present invention) is suitable for use in the present invention. Dark topsheets can generally be made from any of the materials mentioned above by different methods known to those of ordinary skill in the art, including coloring (pimping), dyeing or color printing the material.

A preferred example of a dark topsheet is a hybrid topsheet with an apertured formed film of black polyethylene based available from BP Chemicals under the trademark CPM DH  45105/99 and an outer layer of black nonwoven spunbond polyethylene available from BBA under the trademark T27 CXC. These black materials are obtained using carbon-based pigments.

According to the invention, the apertured topsheet of the present invention has an L Hunter value of less than 60, preferably less than 50, more preferably less than 40, even more preferably less than 30, most preferably less than 20. In embodiments of the invention wherein the topsheet employs different layers, such as apertured polymeric film layer and nonwoven outer layer, all layers individually tailored to this requirement. Preferably, the L Hunter values of the different layers/materials of the topsheet are the same.

In a preferred embodiment the difference Δ Ε in color values between the different layers/materials of the topsheet, such as the nonwoven outer layer and the apertured polymeric film layer, is preferably less than 30, more preferably less than 15, most preferably less than 10. Most preferably, the colors of the different layers/materials of the topsheet match each other (are the same (i.e., have the same Δ Ε)).

In a highly preferred embodiment, the topsheet is black and is typically provided using a carbon-type pigment as the colorant.

It has been surprisingly found that the addition of carbon-type pigments such as graphite to the nonwoven provides improved softness to the nonwoven. Without being bound by theory, it is contemplated that this softness is most likely due to the carbon-type pigment, i.e., graphite, acting as an impurity, reducing the cohesion of the polymer-based material, thereby providing a softer (fuzzier) shaped material that is softer when in contact with the skin. Thus, in a preferred embodiment of the present invention, the absorbent article has a dark colored nonwoven topsheet in which the color is provided by a carbon-based pigment such as graphite. When considering dark undergarments, such absorbent articles having dark nonwoven topsheets wherein the dark color is provided by a carbon-based pigment are not only more discreet to use, but are also more comfortable.

Negative film

The backsheet is generally compliant, flexible and soft feeling. The backsheet prevents the exudates absorbed and contained in the absorbent core from wetting garments, such as undergarments, which contact the absorbent article. The backsheet is preferably liquid impervious (e.g., menses, perspiration, and/or urine). The backsheet can be made of a thin plastic film, although other flexible liquid impermeable materials can also be used. The term "flexible" as used herein refers to materials that are compliant and will readily conform to the general shape and contours of the human body. The backsheet preferably also has elastic properties which allow it to be extensible in one or two directions.

The backsheet may comprise a woven or nonwoven material, a polymeric film such as a thermoplastic film of polyethylene or polypropylene, or a composite material such as a film-covered nonwoven material or a fiber-covered film. Absorbent articles typically comprise a polyethylene film backsheet having a thickness of from about 0.012mm to 0.051 mm.

The backsheet is preferably breathable, i.e. enables the transport of water vapour, or even more preferably air, without sacrificing its primary purpose of providing leakage protection for absorbed liquids. The backsheet may also comprise more than one breathable layer so as to replace a single breathable backsheet layer with at least 2 or 3 layers of different or identical materials. In particular, it is preferred that the breathable backsheet is formed by two breathable layers together.

Preferably, the backsheet of the absorbent article of the present invention has an L Hunter value of less than 60, more preferably less than 40, even more preferably less than 30, most preferably less than 20. Preferably, the difference in L Hunter values between the backsheet and the topsheet is less than 20, preferably less than 15, more preferably less than 10. Preferably, the backsheet has the same L Hunter value as the topsheet of the absorbent article.

In a preferred embodiment, the difference in color values between the topsheet and the backsheet, Δ Ε, is less than 40, preferably less than 30, more preferably less than 20, most preferably less than 15. The backsheet is typically the same color as the topsheet (i.e., Δ Ε is the same). In a preferred embodiment of the invention, both the topsheet and the backsheet are black.

According to the invention, the polyethylene backsheet, or indeed any backsheet made of a polymeric material, can be provided in any colour, including dark colours, by using fillers matching the colour in question. For example, a dark colored backsheet is provided by using a suitable filler/pigment, preferably a dark colored filler/pigment, rather than a conventional white material such as titanium dioxide. As one of ordinary skill in the art will appreciate, the dark color of the backsheet may be provided in the same manner as a dark colored topsheet.

Lower surface layer

The absorbent article of the present invention comprises as an essential element an underlying layer which is visible through the topsheet.

The lower layer has an L Hunter value of less than 60, preferably less than 50, more preferably less than 40, further preferably less than 30, most preferably less than 20. The difference Δ L between the L Hunter values of the topsheet and the underlying layer is typically less than 20, preferably less than 15, more preferably less than 8, further preferably less than 5, most preferably less than 3. Preferably, the L Hunter value of the underlying layer is the same as or less than the lhuter value of the topsheet.

In a preferred embodiment, the difference Δ Ε in color values of the topsheet and the underlying layer is less than 40, preferably less than 30, more preferably less than 20, most preferably less than 10. In a preferred embodiment, the underlying layer is the same color (i.e., the same Δ Ε) as the topsheet, preferably black.

The underlying layer may be provided by a single layer/material or multiple layers/materials. Importantly, the underlying layer visible through the topsheet is provided by any material directly adjacent to the topsheet and visible through the topsheet. Thus, in the case where a single layer/material does not extend across the entire surface adjacent to the topsheet, the underlying layer may be provided by a different material/layer.

As with the topsheet and backsheet, any conventional method for providing an underlying layer having a dark color, known to those of ordinary skill in the art, is suitable for use in the present invention.

In one embodiment of the invention, the underlying layer is provided by at least a portion of the second layer (also referred to as the secondary topsheet). Such a second layer may be provided by a variety of materials such as woven materials, nonwoven materials, polymeric materials such as apertured formed thermoplastic films, apertured plastic films, hydroformed thermoplastic films, porous foams, reticulated thermoplastic films, and thermoplastic scrims. Any of the materials described above for the topsheet may be used for the second layer.

In a preferred embodiment, the underlying layer is provided by a second layer, which is preferably located beneath the entire surface of the apertured topsheet, i.e. the second layer extends to the periphery of the topsheet such that the second layer is located beneath the entire surface of the topsheet. The second layer is positioned between the absorbent core and an apertured topsheet such as an apertured polymeric film and/or nonwoven. In this preferred embodiment, the second layer is capable of masking any further underlying layers, regardless of their color, including, for example, light colored absorbent cores having an L Hunter value of 65 or greater, preferably greater than 70 and more preferably greater than 80, such as conventional white absorbent cores. Advantageously, this embodiment provides a dark colored article in a timely and cost effective manner in which the dark colored apertured topsheet and underlying layers are visible through the apertured topsheet, which article is completely discreet in use when used in dark colored undergarments without the need for an absorbent core that is dark in color itself. In fact, this facilitates process flexibility and raw material supply, and is cost effective. Advantageously, such absorbent articles are capable of masking and retaining in the absorbent core any bodily fluids, especially menstrual fluids, discharged thereon. In this embodiment, the light colored absorbent core extends or does not extend to the periphery of the article such that the absorbent core is visible at the lateral edges of the article underlying the dark colored topsheet and the secondary layer. While the embodiment wherein the absorbent core having an L Hunter value of 65 or greater (preferably a white absorbent core) extends to the periphery of the absorbent article so as to be at the lateral edges of the absorbent article is not a completely discreet preferred embodiment, the absorbent core visible at the lateral edges of the article may serve as a visual indicator of body fluid loading and thus may serve as an indicator of when to replace such dark colored absorbent articles. In other embodiments where a light colored absorbent core (e.g., white) does not extend to the periphery of the article, it is prudent to use with a dark colored undergarment by having an apertured topsheet and no absorbent core visible at the edges of the article.

A highly preferred underlying layer is a nonwoven second layer. The nonwoven second layer prevents "bunching" (twisting), i.e., twisting, of the absorbent core either in the pantiliner/pad itself or in the crotch region. The inner layer of the apertured topsheet is preferably secured in contacting relation with the nonwoven secondary layer. This contacting relationship results in the liquid permeating the apertured topsheet, preferably a formed film, faster than if the apertured topsheet were not in contact with the secondary layer.

The material of the nonwoven second layer may be the same as the nonwoven topsheet described above.

In another embodiment, the underlying layer is provided by at least a portion of the absorbent core. This refers generally to absorbent articles without any layers between the topsheet and the absorbent core, i.e., the topsheet is directly adjacent the absorbent core. In one embodiment, the absorbent core extends to the periphery of the topsheet so as to underlie the entire surface of the topsheet. In other embodiments, the absorbent core does not extend to the periphery of the topsheet. In this latter embodiment, the entire absorbent core provides part of the underlying layer. In such embodiments, the topsheet and the backsheet are joined to each other in an area extending outside the periphery of the absorbent core.

In embodiments where the absorbent core is not located beneath the entire surface of the topsheet, the backsheet, or any intermediate layer between the absorbent core and the backsheet (if present), may provide an underlying layer in an area extending outside the periphery of the absorbent core. Thus, in such embodiments, the backsheet and/or any intermediate layer meets the requirements of the underlying layer as defined in the present invention. Thus, in some embodiments, the underlying layer is provided by at least a portion of the backsheet and/or at least a portion of an intermediate layer between the absorbent core and the backsheet. The intermediate layer may be made of any material (e.g., nonwoven, woven, etc.) known to those of ordinary skill in the art.

Absorbent core

The absorbent core may generally be a single entity or comprise several layers. They may include the following components: (a) an optional primary fluid distribution layer; (b) an optional secondary fluid distribution layer; (b) a fluid storage layer; (c) optionally a fibrous layer underlying the storage layer; and (d) other optional components.

a. Optional principal fluid distribution layer

An optional component of the absorbent core of the present invention is the primary fluid distribution layer. The primary distribution layer is typically positioned beneath (if present) and in fluid communication with the topsheet. The primary distribution layer collects body fluid for ultimate distribution to the storage layer. This transport of liquid through the primary distribution layer is not only primarily through the thickness, but also along the length and width of the article.

b. Optional secondary fluid distribution layer

Also optional according to the invention is a secondary fluid distribution layer. The secondary distribution layer is generally located below and in fluid communication with the primary distribution layer. The purpose of this secondary distribution layer is to facilitate collection of fluid from the primary distribution layer and distribution thereof in the longitudinal and transverse directions of the product prior to transfer to the underlying storage layer. This helps to take full advantage of the fluid capacity of the underlying storage layer.

c. Fluid storage layer

The fluid storage layer is typically located beneath and in fluid communication with the primary or secondary distribution layer.

The fluid storage layer may be any absorbent member capable of absorbing or retaining liquids such as menses and/or urine. The fluid storage layer can be made in a variety of sizes and shapes (e.g., rectangular, oval, hourglass, asymmetric, etc.) and from a variety of liquid-absorbent materials commonly used in sanitary napkins and absorbent articles such as comminuted wood pulp, which is commonly referred to as airfelt. Examples of other suitable Absorbent materials include creped cellulosic fillers, modified crosslinked cellulosic fibers (such as U.S. patent 5,217,445 issued to Young et al at 6.8.1993), capillary channel fibers (i.e., fibers Having intra-fiber capillary channels such as those described In U.S. patent 5,200,248 issued to Thompson et al at 4.6.1993), Absorbent foams (such as those described In U.S. patent 5,260,345 issued to DesMarais et al at 11.9.1993 and U.S. patent 5,268,244 issued to DesMarais et al at 12.7.1993), Thermally Bonded airlaid materials (such as those described In U.S. patent application publication No. entitled "catalytic Absorbent Structures Having a hollow fiber reinforced Structures such as" short fibers used In catalytic fibers, fibrous fibers and fibrous fibers, "synthetic Absorbent fibrous materials such as those described In U.S. patent application publication No. 08/141,156, published by Richards et al at 21.1993), Thermally Bonded airlaid foams, and fibrous materials (such as described In composite Absorbent fibrous materials, Polymer fibers, hydrogel-forming polymer gels, peat moss, tissue including tissue wraps and tissue laminates, or any equivalent material or combination of materials. Suitable fluid storage layers comprising foam are described in european applications 0598833, 0598823 and 0598834. Suitable fluid storage layers comprising tissue laminates, between which superabsorbent or gelling agent particles are contained, are described in international patent applications WO 94/01069 and WO 95/17868.

The fluid storage layer preferably comprises a superabsorbent or gelling material commonly referred to as "hydrogel", "superabsorbent", "hydrocolloid" material. Absorbent gelling materials are those materials which, upon contact with aqueous fluids, especially body fluids, take up such fluids and thus form hydrogels. These absorbent gelling materials are generally capable of absorbing large quantities of aqueous body fluids and also of retaining these absorbed fluids under moderate pressures. These absorbent gelling materials are typically in the form of discrete, non-fibrous particles. However, according to the present invention, these superabsorbent gelling materials may also be provided in non-particulate form, preferably in fibrous form.

In the fluid storage layer, these absorbent gelling materials may be dispersed homogeneously or non-homogeneously in a suitable fibrous matrix, also referred to as a carrier. Suitable carriers include cellulosic fibers in the form of fluff, such as those typically used in absorbent cores. Modified cellulose fibers such as stiffened cellulose fibers may also be used. Synthetic fibers may also be used and include those made from: cellulose acetate, polyvinyl fluoride, polyvinylidene chloride, acrylics (e.g., Orlon), polyvinyl acetate, insoluble polyvinyl alcohol, polyethylene, polypropylene, polyamides (e.g., nylon), polyesters, bicomponent fibers, tricomponent fibers, mixtures thereof, and the like. Preferred synthetic and man-made fibers have a fiber denier of about 3 to 25 denier per filament, more preferably about 5 to 16 denier per filament. It is also preferred that the fiber surface be hydrophilic or treated to be hydrophilic. The storage layer may also include fillers such as perlite, diatomaceous earth, vermiculite, etc. that reduce rewet problems. Additionally, the storage layer may comprise an adhesive, including but not limited to Latex adhesive, which may be sprayed as an aqueous solution onto the surface of the storage layer prior to curing.

If the absorbent gelling material is non-uniformly dispersed in the fibrous matrix, the storage layer may be locally uniform, i.e. have a gradient of distribution in one or several directions over the size of the storage layer. Thus, the non-uniform distribution comprises a fibrous carrier laminate as enclosed by the absorbent gelling material.

Preferably, the storage layer comprises 5-95%, preferably 5-50%, more preferably 8-35% of absorbent gelling material. Furthermore, the storage layer may comprise 5-95%, preferably 50-95%, more preferably 65-92% carrier fibers.

Suitable absorbent gelling materials for use in the present invention most typically comprise substantially water insoluble, slightly cross-linked, partially neutralized, polymeric gelling materials. The material forms a hydrogel upon contact with water. Such polymeric materials can be prepared from polymerizable, unsaturated, acid-containing monomers. Unsaturated acidic monomers suitable for use in preparing the polymeric absorbent gelling materials used in the present invention include those listed in U.S. Pat. No. 4,654,039 granted 3/31 1987 (Brandt et al) and RE32,649 granted 4/19 1988. Preferred monomers include acrylic acid, methacrylic acid and 2-acrylamido-2-methylpropanesulfonic acid.

Regardless of the nature of the basic polymer component of the hydrogel-forming polymeric absorbent gelling materials, such materials are typically slightly crosslinked. Crosslinking serves to render the hydrogel-forming polymeric gelling materials substantially water-insoluble, and thus crosslinking determines, in part, the gel volume and extractable polymer characteristics of hydrogels formed from these polymeric gelling materials. Suitable gelling agents are well known in the art and include those as described in detail in U.S. Pat. No. 4,076,663(Masuda et al), issued 2/28 1978. Preferred crosslinkers are diesters or polyesters of unsaturated mono-or polycarboxylic acids with polyols, bisacrylamides and di-or triallylamines. Other preferred crosslinking agents are N, N' -methylenebisacrylamide, trimethylolpropane triacrylate and triallylamine. The crosslinking agent may generally constitute about 0.001 to 5 mole%, more preferably about 0.01 to 3 mole%, of the final hydrogel-forming polymeric material.

The slightly crosslinked, hydrogel-forming polymeric gel materials are typically used in their partially neutralized form. For purposes of the present invention, such materials are considered partially neutralized when at least 25 mole percent, preferably at least 50 mole percent, of the monomers used to form the polymer are acid group-containing monomers that have been neutralized with salt-forming cations. Suitable salt-forming cations include alkali metals, ammonium, substituted ammonium, and amines. This percentage of the total monomers of the neutralized acid group containing monomers employed is referred to herein as the "degree of neutralization".

Although these absorbent gelling materials are generally disclosed in the prior art as particulate (granular), it is also possible in the present invention for the absorbent gelling material to be non-particulate, for example as a macrostructure such as a fiber, sheet or strip. These macrostructures can be prepared by the following method: the method comprises the steps of forming particulate absorbent gelling materials into aggregates, treating the aggregated materials with a suitable cross-linking agent, compacting the treated materials to densify them and form coherent objects, and then curing the compacted aggregates to react the cross-linking agent with the particulate absorbent gelling materials to form a composite, porous absorbent macrostructure. Such porous, absorbent macrostructures are disclosed, for example, in U.S. Pat. No. 5,102,597(Roe et al), issued 4/7 1992.

According to a particularly preferred embodiment of the invention, the absorbent core comprises only one layer, preferably a fluid storage layer.

Any method known to those of ordinary skill in the art for coloring materials may also be used to color the absorbent core, including coloring (slimming), dyeing (dying) and/or color printing the material.

d. Optional fibrous layer

An optional component included in the absorbent core of the present invention is a fibrous layer adjacent to, and typically underlying, the storage layer. The underlying fibrous layer generally provides the same function as the secondary fluid distribution layer.

e. Other optional Components

The absorbent core of the present invention may include other optional components (components) typically present in absorbent webs. For example, reinforcing scrims (scrims) may be provided within or between the layers of the absorbent core. Such reinforcing scrims should be configured in such a way as not to form an interfacial barrier to fluid transport, particularly when located between the layers of the absorbent core. Such reinforcing scrims are generally not required in the absorbent structures of the present invention if they have the structural integrity that normally occurs as a result of thermal bonding.

Another component which may be comprised in the absorbent core of the present invention and which is preferably provided adjacent to or as part of the primary or secondary fluid distribution layer is an odour control agent. Typically, activated carbon coated with other odour control agents, particularly suitable zeolite, silica or clay materials, or activated carbon in addition to the other odour control agents mentioned above, is optionally added to the absorbent core.

Activated carbon is a preferred odour control agent for use in the dark coloured absorbent articles of the present invention, as this material provides excellent odour control properties at low cost.

Physical characteristics of absorbent core

Absorbent cores are generally non-extensible and non-elastic, but they may be made extensible and may also have elastic properties depending on the material selected. The term "extensible" as used hereinafter means that under external forces such as those occurring during use, the structure elongates in the direction of the force or in the direction of a component of the force if only one-way extensibility is provided.

The term "elastic" as used hereinafter means that the extensible structure at least partially returns to its original state after the force causing the elongation ceases to act. The absorbent core may be corrugated or creped in one or more directions to provide some extensibility, while the choice of elastic fibers used in the structure may provide elasticity.

The absorbent core should preferably be thin. A thickness of less than 5 mm, preferably less than 3 mm, more preferably less than 1.8 mm, and even more preferably between 0.1 mm and 1.8 mm is preferred, so that the final article may also have a lower thickness.

Absorbent article design

The dark colored materials noted above can be advantageously used in sanitary napkins, pantiliners, and sweat pads (underarms or collars). The new product design, as a sub-form in the form of a sanitary napkin or panty liner, i.e. a thong shaped sanitary napkin or panty liner, the so-called thong shaped liner, especially benefits from the present invention. The thong liner is designed such that it provides the sanitary napkin or pantiliner with a shape that enables the sanitary napkin or pantiliner to be worn in thong, G-belt underwear or string panties, so that the thong is substantially triangular or trapezoidal.

Optional features for absorbent articles

The absorbent articles of the present invention optionally may comprise all of those components that are typically used in the intended product application. For example, the absorbent article may comprise means such as wings to improve its positioning and anti-soiling properties, especially towards the rear of the article. Such designs are shown, for example, in EP 130848 or EP 134086. The lined strips with wings are shown in US design 394,503, UK design 2,076,491 and 2,087,071 and international filed industrial design DM045544 filed according to Hague agenement, registered on day 21, 10.1998.

If present, the wings preferably match the color of the rest of the article. Indeed, an article design wherein the wings match the L Hunter value of the rest of the article and which is preferably colored is preferred. The reason is that it is rather easy to see when the wings are folded on the outside.

Regardless of whether the wings are specifically designed for use in a thong liner or for use in a conventional absorbent article, the wings may be provided as separate pieces and may be secured to the thong liner or a conventional panty liner or sanitary napkin or they may be integral with the material of the absorbent article, e.g. as an integral extension of the topsheet, backsheet or a combination thereof. If the wings are fixed, they may be fixed in a substantially outward position or may have been preset towards their position of use, i.e. towards the longitudinal centre line. If the wings are integral extensions of the topsheet or the backsheet or both, they are provided with the same L Hunter value and preferably the same color as these materials.

All commonly used components in absorbent products may also be included in the absorbent article of the present invention as long as the absorbent article meets the L Hunter value as defined in the claims.

The most preferred absorbent articles contain a fastening adhesive for attachment. In the case of sanitary napkins, pantiliners, or thong liners, a so-called panty fastening adhesive is preferably present on the backsheet to be fastened to the undergarment. For example, for sweat pads such as underarm sweat pads, direct attachment to adjacent clothing or to the skin of the wearer is also contemplated. Of course, such direct skin attachment, typically provided by a hydrogel or oleogel matrix adhesive (body adhesive), may be used in sanitary napkins or body liners (as opposed to pantiliners).

Examples

Hereinafter, a pantiliner according to the present invention will be described.

Example (option)1

The pantiliner (as shown in fig. 2) comprises:

a black apertured polyethylene formed film 3 having 0.2 square millimeter apertures and 1.6 square millimeter apertures as a topsheet, the apertured formed film having an open area of about 32% (black CPM DH , designation 45105/99, available from BPChemicals, germany);

a second layer 4 made of black nonwoven spunbonded polyethylene (available from BBA, Linotec under the designation T27CXC) extending over the entire surface of the topsheet as the lower layer;

-a spiral layer of adhesive (H2128 , available from Ato Findley) (not shown);

a core 5 of white absorbent fabric (tissue) with 10% superabsorbent fibres (trade name gh.100.1004, unit weight 100 g/m, available from Concert GmbH, Falkenhagen-Germany);

-a spiral layer of adhesive (PM17 , available from Savare) (not shown);

a polyethylene micro-embossed film 6 with black pigment type ST 700 as backsheet, available from Britton Taco ltd. winsford chess UK;

a panty fastening adhesive strip (HL 1461, available from Fuller, Luneburg-Germany) (not shown) and a spunbonded paper 7.

Example 2

The pantiliner (as shown in fig. 3) comprises:

a black apertured polyethylene formed film 3 having 0.2 square millimeter apertures and 1.6 square millimeter apertures as a topsheet, the apertured formed film having an open area of about 32% (black CPM DH , designation 45105/99, available from BPChemicals, germany), and a black nonwoven spunbond polyethylene outer layer 2 (designation T27CXC, available from BBA, Linotec);

a second layer 4 made of black non-woven spunbond polyethylene as the lower layer extending over the entire surface of the apertured polyethylene formed film layer (available from BBA, Linotec under the designation T27 CXC);

-a spiral layer of adhesive (H2128 , available from Ato Findley) (not shown in fig. 3);

a white absorbent textile core 5 with 10% superabsorbent fibres (trade name gh.100.1004, unit weight 100 g/m, available from Concert GmbH, Falkenhagen-Germany);

-a spiral layer of adhesive (PM17 , available from Savare) (not shown in fig. 3);

a polyethylene micro-embossed film 6 with black pigment type ST 700 as backsheet, available from Britton Taco ltd. winsford chess UK;

a panty fastening adhesive strip (HL 1461, available from Fuller, Luneburg-Germany) (not shown in fig. 3) and a release paper 7.

Example 3

The pantiliner (as shown in fig. 4) comprises:

a black apertured polyethylene formed film 3 having 0.2 square millimeter apertures and 1.6 square millimeter apertures as a topsheet, the apertured formed film having an open area of about 32% (black CPM DH , designation 45105/99, available from BPChemicals, germany), and a black nonwoven spunbond polyethylene outer layer 2 (designation T27CXC, available from BBA, Linotec);

the lower layer portion is provided by a black absorbent textile core 5 comprising 10% superabsorbent fibres, which is located in the centre of the article and does not extend to the periphery of the topsheet but is located in an area extending beyond the periphery of the absorbent core, the lower layer is provided by a portion of the backsheet 6 (which extends beyond the periphery of the absorbent core to the periphery of the topsheet);

-a spiral layer of adhesive (PM17 , available from Savare) (not shown in fig. 4);

a polyethylene micro-embossed film 6 with black pigment type ST 700 as backsheet, available from Britton Taco ltd. winsford chess UK;

a panty fastening adhesive strip (HL 1461, available from Fuller, Luneburg-Germany) (not shown in fig. 4) and a release paper 7.

Example 4

The pantiliner (as shown in fig. 2) comprises:

a black nonwoven spunbond polyethylene outer layer 2 (brand T27CXC, available from BBA, Linotec) extending over the entire surface of the pantiliner as topsheet;

a second layer 4 made of black nonwoven spunbond polyethylene (brand T27CXC, available from BBA, Linotec) extending over the entire surface of the topsheet as the lower layer;

-a spiral layer of adhesive (H2128 , available from Ato Findley) (not shown);

a white absorbent textile core 5 with 10% superabsorbent fibres (trade name gh.100.1004, unit weight 100 g/m, available from Concert GmbH, Falkenhagen-Germany);

-a spiral layer of adhesive (PM17 , available from Savare) (not shown);

a polyethylene micro-embossed film 6 with black pigment type ST 700 as backsheet, available from Britton Taco ltd. winsford chess UK;

a panty fastening adhesive strip (HL 1461, available from Fuller, Luneburg-Germany) (not shown) and a release paper 7.

Example 5

The thong pantiliner 10 (as shown in fig. 5 or 6) comprises:

black nonwoven spunbond polyethylene (brand T27CXC, available from BBA, Linotec) extending over the entire surface of the pantiliner as topsheet;

-a spiral layer of adhesive (H2128 , available from Ato Findley);

-as an underlying layer, a whole side (top side) black absorbent textile core (110 g/m) consisting of cellulose fibres and synthetic fibres (bico PE/PP), commercially available from Duni, extending over the whole surface of the topsheet;

-a spiral layer of adhesive (PM17 , available from Savare);

as backsheet a polyethylene micro-embossed film with black pigment type ST 700, available from Britton Taco ltd. winsford chess UK;

panty fastening adhesive strips (HL 1461, available from Fuller, Luneburg-Germany and release paper 7).

For all of the pantiliners exemplified above, the L Hunter value of the topsheet, underlying layer and backsheet is less than 30.

Claims (15)

1. An absorbent article comprising an apertured topsheet, an underlying layer visible through the apertures of the topsheet, and a backsheet, wherein the topsheet and the underlying layer each have an L Hunter value of less than 60.

2. Absorbent article according to claim 1 wherein the topsheet and the underlying layer each have an L Hunter value of less than 50, preferably less than 30 and more preferably less than 20.

3. Absorbent article according to claim 1 or 2 wherein the difference in L Hunter values between the lower layer and the topsheet, al, is less than 20, preferably less than 8 and more preferably less than 5.

4. An absorbent article according to any of the preceding claims wherein the L Hunter value of the underlying layer is equal to or less than the L Hunter value of the topsheet.

5. An absorbent article according to any of the preceding claims wherein the difference Δ Ε in colour values of the topsheet and the underlying layer is less than 40, preferably less than 20, more preferably less than 10, most preferably the topsheet and the underlying layer have the same colour, typically black.

6. An absorbent article according to any of the preceding claims wherein the topsheet comprises apertures having an aperture size of from 0.0001 mm to 5 mm.

7. An absorbent article according to any of the preceding claims wherein said topsheet is a nonwoven and/or apertured polymeric film.

8. An absorbent article according to any of the preceding claims wherein the backsheet has an L Hunter value of less than 60, preferably less than 40, more preferably less than 20 and preferably the same colour as the topsheet.

9. An absorbent article according to any of the preceding claims wherein the underlying layer is provided by at least a portion of the second layer, preferably a nonwoven second layer.

10. An absorbent article according to any of the preceding claims wherein the underlying layer is provided by at least a portion of the absorbent core.

11. An absorbent article according to claim 9 or 10 wherein the lower layer is provided by at least a portion of the backsheet and/or at least a portion of the intermediate layer located between the absorbent core and the backsheet.

12. An absorbent article according to claim 10 or 11 wherein the lower layer is provided by the absorbent core and a backsheet extending beyond the periphery of said absorbent core.

13. An absorbent article according to any of the preceding claims wherein said article is a sanitary napkin or a pantiliner.

14. Use of an apertured topsheet and/or an underlying layer in an absorbent article, said apertured topsheet having an L Hunter value of less than 60, said underlying layer being visible through the topsheet of the absorbent article, said underlying layer having an L Hunter value of less than 60, for masking bodily fluids discharged onto said article.

15. Use of a perforated topsheet having an L Hunter value of less than 60 in an absorbent article, said topsheet being a nonwoven topsheet wherein the color is provided by a carbon-based pigment, preferably graphite, for improved softness to the skin.