WO2017082834A1

WO2017082834A1 - Single color shade effect

Info

Publication number: WO2017082834A1
Application number: PCT/TR2015/000337
Authority: WO
Inventors: Eylem CANBOLAT; Serdar Soylemez; Fikret Koc
Original assignee: HAYAT KIMYA SANAYI AS
Current assignee: HAYAT KIMYA SANAYI AS
Priority date: 2015-11-11
Filing date: 2015-11-11
Publication date: 2017-05-18
Anticipated expiration: 2018-05-11

Abstract

The present invention is about a feminine hygiene article comprising a topsheet, a backsheet, an acquisition layer and a core layer. The core layer defines a core area between topsheet and backsheet which is completely covered by the topsheet. The acquisition layer is placed on the core layer and covers 65-85% of the core layer. The core layer of the feminine hygiene article is printed with a color which is different than white wherein, the printed pattern is visible through the facing side of the topsheet. At least 90% of the core layer has colored portion which is underneath the topsheet layer and at least 65-85% of the colored portion is underneath the acquisition layer and topsheet layer. In the present invention single coloring agent is applied on the upper surface of the core layer and different L*a*b* value of the colored portion is obtained when measured from the viewing surface of the topsheet. The color difference of the portions of the printing which are located under the topsheet and acquisition layer and only topsheet layer provides a shade effect. This in term creates a perception of depth within the absorbent article by a user looking upon the viewing surface of the topsheet.

Description

SINGLE COLOR SHADE EFFECT

THE FIELD OF THE INVENTION

The present invention relates to an absorbent article. More specifically, the present invention relates to an absorbent article, such as a sanitary napkin and diaper, which are having multi- tone signal by using one color agent and printing equipment.

BACKGROUND OF THE INVENTION

Absorbent articles such as sanitary napkins, pantiliners and incontinent pads normally comprise a liquid pervious topsheet having a user-facing surface, a liquid impervious backsheet having a garment-facing surface and an absorbent core which is between the topsheet and the backsheet.

These elements of absorbent articles like feminine protection articles namely sanitary napkins and/or panty liners, are typically white in color, thereby providing a hygienic impression. These kinds of devices absorbs colored body fluid in the core layer and changes color to that of the fluid being absorbed. This color change on the article is distasteful to the user. It is desired to provide a clean appearance and a dry surface after the discharge of colored body fluids.

It is known in the art to provide a clean appearance and a dry surface after the discharge of colored body fluids by application of printing on the core to create a perception of depth on an absorbent article by using multiple color to obtain multiple tones when the article is viewed from its top or viewing surface. By this way, the user has a belief that fluid will be absorbed deeper into the absorbent article.

EP 1455713 relates to an absorbent article which has printing with different shades of multiple colors and tones. To obtain this effect, at least two colors of ink which have different L*a*b values are applied on the article. The application of different coloring agent on an absorbent article is not a practical and cost effective method.

The present invention provides this shade effect from the top or viewing surface of the absorbent article, by using single color ink without further modification on the production line. It is a novel method to obtain different shades with one color ink which is the cost effective way of the application. Also, it prevents the manufacturing defects depending on the application of multiple printing units.

BRIEF DESCRIPTION OF THE DRAWINGS While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as forming the present invention, it is believed that the invention will be better understood from the following description which is taken in conjunction with the accompanying drawings in which:

FIG.l is exploded perspective view of an absorbent article according to the present invention; FIG.2 is top view of the absorbent article of Figure 1.

Wherein;

1 : Topsheet

2: Acquisition layer

3: Core layer 4: Backsheet

8: Noncolored portion of the article

9: Colored portion of the article

10: Disposable article

11 : First colored portion of the article 12: Second colored portion of the article

13: First shade

14: Second shade DESCRIPTION OF THE DISCLOSURE

As used herein, the following terms have the following meanings:

"Disposable article" as referred to herein are devices that absorb and contain liquid, and more specifically that are placed against or in proximity to the body of the wearer to absorb and contain the various exudates discharged from the body that are worn in the crotch region of an undergarment and is intended to include sanitary napkins, pantiliners, diapers and incontinence pads (and other articles worn in the crotch region of a garment).

The term "disposable" refers to articles that are generally not intended to be laundered or otherwise restored or reused i.e., they are intended to be discarded after a single use and, possibly, to be recycled, composted or otherwise disposed of in an environmentally compatible manner.

As used herein, the term "core layer" refers to a material or combination of materials suitable for absorbing, distributing, and storing fluids such as urine, blood, menses, and/or other body exudates. Since typical absorbent cores used in feminine hygiene articles are relatively thick and bulky compared to the other layers, they often may be easier to emboss than other layers of the article. The absorbent core, when present, may be generally centered in the middle of the article, and may be disposed away from the periphery of the article to provide improved flexibility along the edges of the article.

The absorbent core of the invention can be made of any suitable liquid-absorbent material. Non-limiting examples of liquid-absorbent materials suitable for use as the absorbent core include comminuted wood pulp which is generally referred to as airfelt; creped cellulose wadding; absorbent gelling materials including superabsorbent polymers such as hydrogel- forming polymeric gelling agents; chemically stiffened, modified, or cross-linked cellulose fibers; meltblown polymers including co-form; synthetic fibers including crimped polyester fibers; tissue including tissue wraps and tissue laminates; capillary channel fibers; absorbent foams; absorbent sponges; synthetic staple fibers; peat moss; or any equivalent material; or combinations thereof.

"Acquisition layer" refers to a material that allows the liquid pass through to absorbent core layer. As used herein, "viewing surface" means that layer of the absorbent article which is intended to be disposed toward or placed adjacent to the body of the wearer during ordinary use. The viewing surface includes a body-facing surface, which is intended to immediately face the body of a consumer while the product is in use. The viewing surface also includes an internal garment facing surface, being opposite to the viewing surface.

"Comprise," "comprising," and "comprises" is an open ended term that specifies the presence of what follows e.g. a component but does not preclude the presents of other features, elements, steps or components known in the art, or disclosed herein.

The term "color" or "colored", as referred to herein include any primary color, i.e., white, black, red, blue, violet, orange, yellow, green, and indigo as well as any declination thereof or mixture thereof. Color measurement can be made with a L Hunter Scale method. This system is based on three variables L*, a*, b*.

FIG.l provides an exploded view of disposable article (10) from top to bottom. The following layers are a topsheet (1), an acquisition layer (2), a colored core layer (3) and a backsheet (4). The "top" of article is defined herein as the surface of the article oriented towards the user's body when in use, and the "bottom" is defined herein as the opposite surface of the article, i.e. the surface that will contact the undergarment directly.

FIG.2 provides a perspective view of the disposable article (10), that shows the color differences between first colored portion (11), and second color portion (12). It also shows the noncolored portion of the article (8). The absorbent article (10) has a liquid-pervious topsheet (1), a liquid impervious backsheet (4), an acquisition layer (2) and a core layer (3) take place between the topsheet and the backsheet. The core layer is an airlaid material containing superabsorbent polymer with white color and has colored parts on its viewing surface from the user facing.

The color of the first shade (13) and the second shade (14) of the colored portion (9) and noncolored portion (8) are measured by the reflectance spectrophotometer according to colors ' L*, a* and b* values.

The difference in color (E*) between the first shade (13) and the second shade (14) should be at least 3,0. Since the difference in color (E*) a human eye can distinguish is at least 2,4 for dark colors. This issues are handled in chapter IV of Hunter's book and also EP1455713 patent. FIG. 2 also provides a dispersable article wherein first shade portion (13) have a lighter color tone compared to second shade portion (14).

Some embodiments are given below, to understand the invention clearly;

In one embodiment herein, the colored portions form a part of the absorbent core whereby the colored portion is viewable from the viewing surface of the topsheet. Any topsheet material that allows the colored portion to be readily seen from the viewing surface of the topsheet is suitable: i.e. formed film material, nonwoven, and combinations thereof.

In another embodiment, shown in FIG 2 the absorbent article has a colored area which is being positioned at least on 70%, at least 80%, at least 90% and up to 100% of the total area of the core layer and an acquisition layer on it which covers at least preferably 65%, more preferably 70%, most preferably 85% length of the bottom layer and at least preferably 65%, more preferably 70%, most preferably 85% of the colored portion is being positioned both under the acquisition layer and the topsheet layer.

In another embodiment, the color is applied on a core layer of the absorbent article. Thus, in order to view the printed area from an external surface of the article, the layers of the article located between the internal printed surface and the acquisition layer and topsheet layer of the article being viewed must have a sufficient transparency according to their opacity values, which is at least 40%.

The colored portion may be obtained with any conventional printing method, such as flexo print or roto gravure printing. The colored portion may be advantageously printed with an ink sufficiently colored to be visible through at least a portion of the topsheet of the article outside the core area. Any colored ink may be used, including, but not limited to black or colors such as, for example, pink, violet, green, purple, blue, yellow, gold, silver, etc., or any combination of different colors. In addition to colored portions obtained by conventional printing, the colored portions obtained by techniques that may not typically be referred to as printing, but that provide the same or a similar effect. For example, it may be possible to provide a similar visual effect by heat crimping a plastic nonwoven layer (e.g. backsheet) so that the crimped area, which then becomes translucent, provides a similar visual effect as an ink printed area.

In one embodiment, the colored portion may be in any color, more preferably dark blue or dark violet colors are applied. The method of the present invention is a method for producing an absorbent article which comprises a liquid-permeable sheet, a liquid-impermeable sheet, an absorber sandwiched between the liquid-permeable sheet and the liquid-impermeable sheet, side sheets joined to at least a part on the right and left both sides of the liquid-permeable sheet, and a colored layer provided between the liquid-permeable sheet and a liquid impermeable sheet, and is provided with at least one color colored portions appearing as color different from the viewing surface of the topsheet depending on the presence of the upper layers on it. The colored portion which is being positioned on the core layer and covered by the acquisition layer has higher light transmittance value than the colored portion which is being positioned on the core layer and covered by the both of the acquisition layer and the topsheet. This light transmittence difference provides a shade effect when looked at from the viewing surface of the topsheet.

In one embodiment, the topsheet used in there can be formed film or nonwoven film.

In another embodiment, the acquisition layers used in this articles can be air laid or air through. A complete technical description of the measuring system can be found in an article by R.S.Hunter, "Photoelectric Color Difference Meter", Journal of the Optical Society of AMERICA, Vol. 48, pp.985-99, 1958. Devices specially designed for the measurement of color on the Hunter scales are described in US Patent Number 3,003, 388 to Hunter et. al., issued October 10, 1961. In general, Hunter Color "L" scale values are units of light reflectance measurement. The higher the "L" value is, the lighter the color. A lighter colored material reflects more light. In particular, in the Hunter Color System, the "L" scale contains 100 equal units of division, absolute black is at the bottom of the scale (L=0) and absolute white is at the top of the scale (L=100). When the color is defined according to this system, L* represents lightness (0= black, 100=white), a* and b* independently each represent a two color axis, a* representing the axis red/green (a+ = red, -a = green), while b* represents the axis yellow/blue (+b= yelllow, -b= blue).

When comparing colors it is useful to calculate the function E for each color where;

E² = L² + a*² + b*² . The difference in color between two adjacent surfaces or two adjacent colors may be represented as follows:

ΔΕ = [(L*2-L*i)² + (a*₂-a* ² + (b*₂-b*i)²]^1/2 "Formula 1" For purposes of the present invention, the colored portion under the topsheet of the inventive samples was used to determine L*₂, a*₂, b*₂, and the colored portion under acquisition layer and topsheet together as measured through the cover layer was used to determine L*₁,a*₁and b*i. ΔΕ was then calculated from these values. Color measurements required to calculate ΔΕ can be made using a tristimulus colorimeter (Minolta Chromameter(R) CR300) using the CIE (International Commission on Illumination) L*a*b* color coordinate standard. The term "uncolored", "non-colored", "white" or the like, as used herein, means those colors having an L* value of at least 90, an a* value equal to 0 + 2, and a b* value equal to 0 +- 2.

For colors to be distinctly seen from the substrate on which they are printed, a single color should have a difference in color from the substrate (or reference) that it is compared against. For example, a red dot printed on white paper will have a distinct ΔΕ. Therefore, dark colors are choosen in this invention.

Color Zone Measurement for Pad Topsheet Appearance

For measuring the L*, a*, and b* values for the invention herein, a standard, industry- recognized procedure is used. The topsheet color is measured using a reflectance

spectrophotometer in accordance with method ASTM E 1164-94, "Standard Practice for Obtaining Spectrophotometric Data for Object-Color Evaluation". This standard method is followed but specific instrument settings and sampling procedure are given here for clarity. Sample color is reported in terms of the CIE 1976 color coordinate standard as specified in ASTM E 1164-94 and ASTM D2264-93, section 6.2. This consists of three values; L* which measures sample "lightness", a* which measures redness or greenness, and b* which measures yellowness or blueness.

Apparatus

Reflectance Spectrophotometer 45°/0° Hunter Labscan XE, or equivalent HunterLab Headquarters, 11491 Sunset Hills Road, Reston Va. Standard plate Sandard Hunter White Tile Source: Hunter Color. Equipment Preparation

1. Assure that the Spectrophotometer is configured

Illumination Type C

Standard Observer 2'

Geometry 45/0[deg.] Measurement angle

Port Diameter 0.70 inch

Viewing area 0.50 inch (and no smaller)

UV Filter Nominal

2. Calibrate the spectrophotometer using standard black and white tiles supplied with the instrument according to manufacturer's instructions before beginning any testing.

Sample Preparation

1. Unwrap, unfold and lay the product or pad samples fiat without touching or altering the color of the body facing surface.

2. Areas on the body- facing surface of the product should be selected for measurement and must include the following:

- The non-colored portion of the topsheet.

-The colored portion of the topsheet; including the two or more shaded portions.

-Any other portions of the topsheet above the absorbent core having a visibly or measurably different color from the first shaded zone. Embossed channels and folds should not be included in zones of measurement as they may skew the proper results. Measurements should not be made on sites where the border of two shaded portions are overlapping.

Different samples are prepared by using different topsheet or acquisition layer or different colored absorbent core.

Sample 1 is prepared by using formed film topsheet layer, air through acquisition layer and one tone dark blue colored absorbent core.

Sample 2 is prepared by using formed film topsheet layer, air laid acquisition layer and one tone dark blue colored absorbent core. Sample 3 is prepared by using non-woven topsheet layer, air through acquisition layer and one tone dark blue colored absorbent core. Sample 4 is prepared by using non-woven topsheet layer, air laid acquisition layer and one tone dark blue colored absorbent core.

Sample 5 is prepared by using formed film topsheet layer, air through acquisition layer and one tone dark violet colored absorbent core. Sample 6 is prepared by using formed film topsheet layer, air laid acquisition layer and one tone dark violet colored absorbent core.

Sample 7 is prepared by using non-woven topsheet layer, air through acquisition layer and one tone dark violet colored absorbent core.

Sample 8 is prepared by using non-woven topsheet layer, air laid acquisition layer and one tone dark violet colored absorbent core.

Denier of acquisition layers can be any suitable commercially used articles. In the samples prepared, used air through acquisition layer is 40 g m² and used air laid acquisition layer is 59 g/m² examplarly.

Test Procedure

1. Operate the Hunter Colorimeter according to the instrument manufacturer's instructions.

2. Pads should be measured laying flat over the 0.70 inch aperture on the instrument. A white tile should be placed behind the pad.

3. The pad should be placed with its long direction perpendicular to the instrument.

4. Measure the same zones selected above for at least 3 replicate samples and take the avarage values.

Calculation Reporting

1. Record the L*,a*,b* values to the nearest 0.1 units.

2. Take the average L*, a*, b* for each zone measured.

3. Calculate ΔΕ* between different shaded portions according to Formula 1. TABLE I : Calculated Results of Difference in Color (ΔΕ*) Between Adjacent Surfaces of Topsheet Types and Acquisition Layer According to Formula I.

Table I above clearly shows the AE*s obtained from different samples. Table clarifies that; both samples formed from formed film and non-woven types of topsheet used with air laid acquisition layer show better penetration of light compared to airthrough acquisition layer used samples. Therefore air laid acquisition layer type is prefered in the present invention.

The result of AE*s are greater than 3,0, that shows there are predictable difference in lightness/darkness between the two points of measurements i. e. between the first colored portion and second colored portion.

Opacity Test Method

Opacity is a measure of the capacity of a material to obscure the backsground behind it. The value for opacity is obtained by dividing the reflectance obtained with a black backing (RB) for the material, by the reflectance obtained for the same material with a white background (RW). This is called the contrast ratio (CR) method.

%Opacity = ^ X 100

Using a Hunter Colorimeter set to XYZ color scale, opacity is defines as; Y value of topsheet and acquisition layer , _ _Λ ,,_ ,

% Opacity = ·— - — x 100 "Formula 2"

^J Y value of topsheet Sample Preparation

A specimen of suitable size (generally about 10 cm square) is cut for analysis. The specimen must be free of creases, wrinkles, tears and other obvious defects.

If the opacity of the material is affected by temperature and/or humidity, the specimens must be conditioned under standart TAPPI conditions (73 °F(22.8 °C); 50% RH) until equilibrium is reached, and measured under those conditions.

If the topsheet material is treated with one or more surfactants, the material used for the test is the surfactant-treated topsheet material.

Equipment

Hunter Labscan XE available from the Hunter Associates Laboratory, Inc., USA. The instrument is configured as follows:

Geometry 45°/0°

Clor Scale XYZ Illuminant D65

Observer 10°

The colorimeter is calibrated using the standard gloss black glass and gloss white tile supplied with the instrument according to the manufacturer's instructions.

Test procedure

1. The topsheet is placed on the sample holder and inserted into the colorimeter and color scale Y value is measured.

2. The topsheet and acquisition layer together is placed on the sample holder and inserted into the colorimeter and color scale Y value is measured.

3. Obtained color scale Y values are set into the opacity Formula 2 to obtain opacity values in percent. The specimen is placed on the sample holder and inserted into the colorimeter according to the manufacturer's instructions. The machine direction of the specimen should be aligned front to back in the instrument. The Y reading is recorded to the nearest 0.1 unit. The procedure is repeated 10 times on different parts of the sample and the avarega value is taken for the calculations.

Ten specimens are measured and the opacity results averaged to obtain the %opacity value for the material.

TABLE II: Calculated Results of Opacity Values Between Adjacent Surfaces of Topsheet and Acquisition Layer Types in Percentages (%) According to Formula 2.

Table II above clearly shows the results of the opacity tests of different samples. It can be seen that, the samples have sufficient transparency to be seen clearly from the top surface of the articles.

Claims

A disposable article comprising; a topsheet (1), a backsheet (4), a colored core layer (3) having a single colored upper surface, being positioned between said topsheet and backsheet and an acquisition layer (2) being positioned between said topsheet and said colored core layer characterized in that; said colored core layer is viewable from the viewing surface of said topsheet, wherein at least 90% of said upper surface of said core layer is colored and said acquisition layer covers 65-85% of said core layer and said disposable article has a first colored portion and a second colored portion on said upper surface of said colored core layer, wherein, first colored portion is that portion of said colored core layer upper surface which is covered by said topsheet and said acquisition layer and said second colored portion is that portion of said colored core layer upper surface which is covered by said topsheet.

A disposable article according to claim 1, wherein said topsheet is non- woven or formed film type, preferably non-woven type and acquisition layer is air laid or air through type, preferably air laid type.

A disposable article according to claim 1, wherein said colored core layer has at least 90% printed area on its upper surface.

A disposable article according to any one of the preceding claims, wherein the difference in color (ΔΕ*) between the first colored portion and second colored portion area is at least 3,0.

A disposable article according to any one of the preceding claims wherein, the opacity of the topsheet and acquisition layer in comparision with topsheet is more than %40, wherein opacity is defined as comparision of color scale Y value of topsheet and acquisition layer with color scale of Y value of topsheet in percentage.

6. A disposable article according to any one of the preceding claims wherein, the colored portion under the acquisition layer and the colored portion under topsheet and acquisition layer together is visible from the viewing surface of topsheet and the opacity of the topsheet and the acquisition layer are homogeneous throughout themselves.

7. A disposable article according to any one of the preceding claims wherein, the difference in color (ΔΕ*) between said first colored portion and said second colored portion is at least 3,0 and the opacity of the topsheet and acquisition layer together in comparision to topsheet is more than 40%.

8. A disposable article according to any one of the preceding claims wherein, the difference in color (ΔΕ*) is obtained by using single coloring agent to create a perception of depth within the absorbent article by a user looking upon the viewing surface of the topsheet and said colored core layer and said core layer with said acquisition layer are viewable from the viewing surface of said topsheet.

9. A method of manufacturing a disposable article according to any preceding claims comprising, placing an acquisition layer and a core layer between a backsheet and a topsheet layer, wherein said acquisition layer covers 65-85% of said core layer and at least 90% of said upper surface of said core layer is colored.