DE4321155C2 - Flat, non-woven fiber layer material for use in hygiene articles - Google Patents

Description

The invention relates to a flat, non-woven fiber layer material, in particular made of nonwoven, tissue or the like for use in hygiene articles, especially in sanitary napkins, which fiber layer material at least in its direction of thickness has liquid-transporting properties.

Nonwoven fibrous sheet materials are commonly used e.g. B. as kör Persistent cover layers used on the absorbent pads of sanitary napkins. Such cover layers are characterized by skin friendliness and tactile Softness, however, are in their rewetting properties and the visual len opacity in need of improvement.

Alternatively, cover layers of sanitary napkins can also be made from a two- or three-dimensional, perforated plastic film consist of a de Finished, qualitatively adjustable ratio between closed, d. H. hydrophobic or liquid-impermeable surface and perforated, has liquid-permeable surface. Such cover layers have with regard to rewetting and visual covering power compared to nonwovens with open fiber structure significant advantages. This is based u. a. represents on, at least with three-dimensionally perforated foils that are on their Absorbing cone protruding opening side, a so-called "Ab stand holder effect "between the absorbent and the top of the Ab top layer is caused, which reduces rewetting. Such a hole However, films do not have the skin familiar from nonwoven cover layers friendliness and tactile softness.  

Hygiene articles are known from the prior art that are liquid have permeable cover layer made of nonwoven material. At least on One surface of the nonwoven material is raised from liquid permeable material applied, between which liquid Passage areas. Such articles are for example in DE 27 08 491 C2, US 4,741,941 A, EP 0 207 904 A1, EP 0 545 423 A1, DE 29 22 993 A1 and DE 39 17 791 A1.

The invention has for its object a flat, non-woven Specify fiber layer material for use in hygiene articles, the under Maintaining its skin friendliness and tactile softness improved Back-wetting properties and a significantly increased visual covering power body fluids located below the layer material shows. In particular, a fiber layer material should be specified that is particularly easy and efficient to manufacture.

This object is achieved by the in the characterizing part of claim 1 specified features solved. By applying the from the surface protrusions of the fiber layer material protruding from liquid permeable material is on the side of this surface on the one hand achieved "spacer effect" mentioned above and on the other hand the open fiber structure of the fiber layer material partially closed, so that in conjunction with the "spacer effect" the rewet is reduced. Because the surface facing away from the elevations conventional cover layers made of fiber layer material practically unchanged remains, skin friendliness and tactile softness are maintained. Screen printing is advantageous since this is a printing technique by means of which printing even on a relatively uneven surface, e.g. B. at a nonwoven material due to the tangled fibers  can, is possible.

Claims 2 to 5 characterize advantageous configurations for the Elevations that also appeal to the fiber layer material aesthetically Give appropriate or functional appearance.

Claims 6 and 7 give advantageous materials for the surveys at. It should be emphasized that the rewetting properties continue by appropriate adjustment of the hydrophobic or hydrophilic Properties of the polymer material used can be optimized.

The height of the elevations from the upper specified in claim 8 surface of the fiber layer material is sufficient to the "Ab stabilizer effect "to ensure specifies that the distance between the fiber sheet material and one of them ter located absorbent z. B. a sanitary napkin, is small enough to when body fluid runs onto the body-side surface of the Fiber layer material a rapid liquid transport through this to reach through to the absorbent. When rewetting from the suction body, which due to its suction behavior leads to a lower liquid volume, the one caused by the surveys is sufficient Distance between the absorbent and the fiber layer material that the Liquid return transport is significantly reduced.

Claims 9 and 10 relate to different embodiments a sanitary napkin in which an inventive fiber layer material as body-side cover layer or intermediate layer between such a body personal cover layer and the absorbent body is used. Derarti On the one hand, hygiene articles and especially sanitary napkins have a  skin-friendly and soft body-side surface, on the other hand greatly improved rewetting properties.

Further features, details and advantages of the invention are according to following description can be seen in the embodiments of the Er subject of the invention with reference to the accompanying figures the. Show it:

Fig. 1 is a photocopy of a micrograph of a fiber sheet material according to the invention,

Fig. 2 is a partial vertical section through a sanitary towel according to the invention with a fiber sheet material as körpersei term covering layer,

FIGS. 3 and 4 are respectively a partial vertical section of sanitary napkins having an inventive fiber sheet material as a rule interim position between the body-side cover layer and absorbent body in two different embodiments, and

Fig. 5 to 12 are schematic plan views of inventive fiber sheet materials with different configurations of its projections.

As is clear from FIGS. 1 and 2, a flat, non-woven fiber layer material according to the invention consists of a nonwoven layer 1 , which is a commercially available, thermally bonded polypropylene carded nonwoven with a basis weight of 20 g / m ² acts. Alternatively, for example, a thermally bonded polypropylene spunbonded fabric with a basis weight of 16 g / m ² or a polypropylene carded nonwoven with a basis weight of 26 g / m ² can be used, which is bonded by a so-called "hot-through-air process" has been.

Such nonwovens have liquid-transporting properties in the thickness direction D ( FIG. 2).

On the viewer of FIG. 1 facing surface 2 of the nonwoven layer 1 , elevations 3 in the form of individual, grid-like knobs 4 are applied by means of screen printing technology. These knobs 4 consist of a liquid-impermeable material, such as a hot melt adhesive (hotmelt) specially developed for screen printing, as is given by hot melt adhesive with the trade name Lunatac D 014BD2 or BD4. Commercially available ethylene / vinyl acetate polymer dispersions, for example the trade name Vinapas EN 426 (hydrophilic) or Vinapas EN 428 (hydrophobic) are also suitable for the surveys 3 .

The grid-like arrangement of the individual knobs 4 leaves between these areas, in which the open fiber structure of the nonwoven fabric layer 1 is retained. The areas located between the knobs 4 thus form passage openings 5 for liquid passage.

A screen type with a screen aperture of approximately 0.7 mm was used for screen printing of the knobs 4 . This results in 120 nubs / cm ² , where the nub diameter ∅ ( FIG. 1) is approximately 0.6 mm. The coverage ratio of the knob surface to the total surface of the nonwoven layer 1 be 46%. The knob height h ( Fig. 2) is 176 µm. The applied amount of hot melt adhesive is 58 g / m ² .

These results as well as corresponding results for sieve types with a Sieve aperture of approx. 1.8 mm or 0.42 mm listed in Table 1 below.

Table 1

Nonwoven: PP card fleece, thermally bonded, basis weight 20 g / m ²

, Surveys: Lunatac D 014BD2, Hot melt adhesive

As is clear from Fig. 2, the nonwoven fabric layer 1 according to the invention can be used with its knobs 4 as a body-side cover layer 6 of a sanitary napkin, the non-knobbed surface 7 of the cover layer 6 facing the outside, that is to say the body side, of the bandage. Since the cover layer 6 retains its skin friendliness and tactile softness.

By the inner on the surface 2 of the nonwoven fabric layer 1 attached burls 4, the nonwoven fabric layer 1 is held by the absorbent body 8 of the sanitary napkin at a distance ( "spacer effect"), so that the nonwoven layer is 1 rückgenäßt in significantly reduced extent during use of the sanitary napkin. This effect is further supported by a hydrophobic design of the material used for the knobs 4 , since body fluid emerging from the absorbent body 8 is repelled downwards.

The improved rewetting properties were compared which can be described as follows:

Test liquids used

Defibrinated sheep blood
Blood replacement fluid

Recipe

14 g tylose (trade name CMC)
10 g NaCl
4 g NaHCO ₃

100 g glycerin

The solution is made up to 1000 ml with distilled water. The Viscosity at the Epprecht Rheomat is 13.0 mPas.

Urine replacement fluid Recipe

urea 21.4 g NaCl 3.0 g K ₂ SO ₄ 2.3 g citric acid 0.3 g MgCL ₂ 0.2 g CaCl ₂ 0.1 g L-histidine HCL 0.5 g Bovine serum albumin 0.1 g (NM ₄ ) ₂ HPO ₄ 2.0 g PH value: 6.0

A cellulose flake absorbent of the following specification was used as the absorbent:
Weight: 8.9 g
Length: 218 mm
Width: 59 mm
Thickness: 19 mm
Density: 0.05-0.07 g / cm ³

This absorbent body was covered with a thermally bonded PP card nonwoven fabric with a basis weight of 20 g / m ² with and without printed hot-melt adhesive knobs with knobs directed towards the absorbent body.

In the rewet test, 5 ml of test liquid at a temperature of 37 ° C is applied to the weighed test specimen by means of a burette in a time of 20 seconds, the burette tip being in contact with the test specimen surface. After waiting 10 minutes, a stack of filter paper consisting of at least 10 individual layers is weighed and placed on the test specimen. This arrangement is loaded with a cuboid mass body of 5 kg and the base of 110 × 110 mm ² for 15 seconds. The stack of fiter paper is then weighed again and the backwetting surface is determined planimetrically with the lowest paper layer.

The measured quantity and the rewetting factor are calculated from this according to the following definitions:

Rewet amount = weight of wet filter paper stack - weight of dry filter paper stack

Rewetting factor = rewetting amount × rewetting area.

The test results by means of this rewetting test can be found in tables 2 and 3 following this description. It follows directly from this that the rewetting properties improve considerably as a result of the elevations printed on the nonwoven layer 1 . The test results listed in Table 2 in the three right-hand columns (sieve aperture 1.8 or 0.7 or 0.42 mm) were obtained using a test set-up that corresponds to the bandage set-up according to FIG. 2.

The experimental setup on which Table 3 is based corresponds to the construction of a sanitary napkin shown in FIG. 4, where a nonwoven fabric layer 1 'according to the invention is used as an intermediate layer between a cover layer 9 made of conventional thermo-strengthened PP card nonwoven fabric with a basis weight of 20 g / m ² and the absorbent body 8 is. This nonwoven layer 1 'has on its surface 2 ' facing the cover layer 9 'knobs 4 made of hot-melt adhesive, which were applied by means of screen printing with a screen with a screen aperture of 0.7 mm. The PP nonwoven fabric of the nonwoven fabric layer 1 'is of the same quality as that of the cover layer 9 .

Due to the "spacer effect" achieved by means of the knobs 4 between the covering layer 9 and the nonwoven layer 1 ', the rewetting properties are again significantly improved, as can be clearly seen from the values in Table 3.

Another possible embodiment of a sanitary napkin is shown in FIG. 3. Here, a conventional PP nonwoven fabric with a surface weight of 20 g / m ² is used as the cover layer 9 . Below this is a tissue layer 10 , which in turn is printed on its surface 8 facing the suction body 2 with the knobs 4 .

In Figs. 5 to 12, different configurations for the protrusions 3 are Darge provides, these surveys show consistently using black 3, while the section between them located so that the white areas mark the nonwoven layer 1 itself and through holes 5.

The nonwoven layer 1 shown in Fig. 5 corresponds substantially to the layers of nonwoven fabric 1 shown in Figs. 1 and 2.

In the exemplary embodiments according to FIGS. 6, 8, 9 and 11, the elevations 3 form lattice-shaped structures, circular through openings 5 being provided according to FIG. 6. In the exemplary embodiments according to FIGS. 8 and 11, the elevations 3 realizing webs 11 form passage openings 5 between them, which are hexagonal in plan view. In FIG. 8 the through openings 5 are arranged in linear rows, whereas in the embodiment according to FIG. 11 a honeycomb-like structure is achieved.

In FIG. 9, the webs 11 form a diamond shape between them, in a grid-like manner at ordered passage openings 5 .

In Figs. 7 and 12 individual elevations 3 are again provided, which are designed hexagonal in plan view. Their arrangement is again made in linear rows ( Fig. 7) or honeycomb-like ( Fig. 12).

Fig. 10 shows individual surveys 3 , which are diamond-shaped, arranged in a grid pattern.

Table 2

Back-wetting properties of thermally bonded PP card nonwoven with a weight of 20 g / m ² with and without hot-melt adhesive screen printing

Use as a cover nonwoven

Sieve aperture (mm)

Table 3

Back-wetting properties of thermoformed PP carded nonwoven composite

PP cover fleece, weight per unit area 20 g / m ² / PP fleece of the same quality with hot-melt print screen aperture of 0.7 mm, print on the cover fleece side / fluff absorbent body

Claims (10)

1. Flat, non-woven fiber layer material in particular made of nonwoven or tissue for use in hygiene articles, especially in women bind, which fiber layer material has at least in the thickness direction (D) liquid-transporting properties, characterized in that on at least one surface ( 2 ) of the fiber layer material as ( 1 , 10 ) from the surface ( 2 ) protruding elevations ( 3 ) made of liquid impermeable material are applied, which elevations ( 3 ) have passage areas ( 5 ) between them for liquid passage, the elevations ( 3 ) being screen printed the fiber layer material ( 1 , 10 ) are printed and consist of a hot melt adhesive. 2. Fiber layer material according to claim 1, characterized in that the elevations ( 3 ) consist of individual, preferably grid-like arranged knobs ( 4 ). 3. fiber layer material according to claim 2, characterized in that the knobs ( 4 ) are circular or polygonal in plan view, in particular diamond-shaped or hexagonal. 4. Fibre layer material according to claim 1, characterized in that the elevations ( 3 ) consist of continuous webs ( 11 ) forming a lattice-shaped structure in plan view. 5. fiber layer material according to claim 4, characterized in that the through openings ( 5 ) formed between the webs ( 11 ) are circular or polygonal in plan view, in particular diamond-shaped or hexagonal. 6. fiber layer material according to one of claims 1 to 5, characterized in that the elevations ( 3 ) consist of hydrophobic or hydrophilic polymer material. 7. fiber layer material according to claim 6, characterized in that the elevations ( 3 ) consist of an ethylene / vinyl acetate polymer dispersion. 8. fiber layer material according to one of claims 1 to 7, characterized in that the elevations ( 3 ) have a standing height (h) from the upper surface ( 2 ) of the fiber layer material ( 1 , 10 ) of 50 to 300 microns. 9. hygiene article, in particular sanitary napkin, with an absorbent body ( 8 ) and a body-side cover layer on the absorbent body ( 8 ), which is formed by a fiber layer material according to one of claims 1 to 8, characterized in that the elevations ( 3 ) of the fiber layer material are facing the absorbent. 10. hygiene article, in particular sanitary napkin, with an absorbent body ( 8 ) and a body-side cover layer ( 9 ), an intermediate layer ( 10 , 1 ') of fiber layer material according to one of claims 1 between the cover layer ( 9 ) and the absorbent body ( 8 ) to 8, characterized in that the elevations ( 3 ) are arranged at least on the surface ( 2 , 2 ') of the intermediate layer ( 10 , 1 ') facing the absorbent body ( 8 ) or cover layer ( 9 ).