SE465806B - ABSORPTION BODY SHOULD TRANSPORT LIQUID IN THE WAY OF AN ABSORBING LAYER IN A PRIOR USE OF ABSORPTION - Google Patents

Description

It is associated with considerable difficulties to find a suitable material composition for a batting which meets the above requirements, since the requirements require properties of the batting which to some extent are in opposite relation to each other.

Coarse heat-fusible fibers, for example polyester, polyethylene or polypropylene fibers, provide a dimensionally stable, resilient and resilient fiber batt. With such fibers, however, a fiber wadding is obtained without any fine capillary system which can conduct liquid in the desired direction, for example to an absorption layer arranged in connection with the fiber wadding. Such a fiber wadding also does not become very soft and comfortable to use in contact with the skin.

Fine hydrophilic fibers, for example viscose fibers or cellulose-based fibers, on the other hand give a dense soft fiber wadding with a fine-meshed capillary system and thus good liquid-transporting properties, but also a wadding that easily collapses in the wet state.

According to the present invention, however, a fiber wadding has been provided in which the above difficulties and disadvantages have been overcome.

An absorbent body according to the invention has the features stated in claim 1.

Due to the presence of both coarse and fine fibers in the batt, a batt is obtained which is very well suited for its purpose, ie to be both dimensionally stable and resilient in the wet state, and partly liquid-transporting. It has also been found to be of great importance to the invention that the fibers are present in a certain mixing ratio. It has been found to be appropriate for the batt to consist of 80-90% by weight of coarse fibers and 10-20% by weight of fine fibers.

It has further been found that a particularly suitable fiber mixture consists of 85% by weight of coarse fibers and 15% by weight of fine fibers. »X 10 15 20 25 30 35 3 465 806 The presence of coarser fibers causes the fibrous cotton wool to become bulky and have resilient properties, ie the fibrous cotton wool springs back after it has been compressed, for example under the influence of a user's weight. Another way to increase the stability of the batt is to bind the fibers, for example by means of heat, whereby a thermobonded batt is obtained. If the coarse fibers consist of heat-digestible so-called thermoplastic fibers of the bicomponent fiber type, these in molten form can serve as a binder in such a thermobonded wadding, without the need for any additional binder. An additional advantage of a tied batting is also that it is much easier to handle in production than an unbound batting.

The task of the fine fibers is to fill in the gaps between the coarse fibers so that the fiber batt gets a structure with many fine capillaries, which is a prerequisite for liquid transport in the batt. It is particularly advantageous for the fine fiber to consist of a hydrophilic fiber, since a somewhat absorbent batt is then also obtained.

According to the invention, it is thus possible to obtain a thermobonded wadding which is both dense, bulky, dimensionally stable and resilient as well as liquid-transporting and liquid-absorbent.

An absorbent body embodied according to the invention will be described in more detail below with reference to exemplary embodiments shown in the accompanying drawings.

Figure 1 shows in plan view an absorbent article comprising an absorbent body according to the invention with the side intended to face the user facing the viewer; Figure 2 shows in section along the line II-II in Figure 1 a first embodiment of the absorbent article; Figure 3 shows in section along the same line II-II in Figure 1 a second embodiment of the absorbent article.

Figures 1 and 2 show a diaper 1 as an example of an absorbent article. The diaper 1 has a liquid-permeable layer 2, preferably of non-woven fabric, an absorbent body 3 arranged below this layer 2, which comprises a liquid-receiving layer 4 and an absorbent layer 5 arranged below it. the absorption layer 5 is a liquid-impermeable layer 6 applied, which can for instance consist of a liquid-tight polyethylene film or a liquid-tight, but vapor- and air-permeable plastic film. The liquid-impermeable layer 6 and the liquid-permeable layer 2 both extend a distance beyond the edges of the absorbent body 3 and are joined there by means of adhesive, in a conventional manner. The two layers 2,6 can also be connected to the absorbent body 3 in any way if it is found to be suitable, for example to stabilize the absorbent body.

The liquid-receiving layer 4 of the absorbent body 3 consists of a fiber wadding, which comprises a mixture of coarse fibers and fine fibers. It has been found to be particularly advantageous, as illustrated in the following examples, that the fibrous wadding consists of a mixture of heat-fusible fibers and hydrophilic fibers. The heat-fusible fibers can be, for example, polyester fibers, polyethylene fibers, bicomponent fibers or mixtures thereof. It is especially preferred to use bicomponent fibers, wherein the constituent components can be polypropylene / polyethylene, polyester / polyester, polyester / polyethylene.

It is particularly convenient to use a bicomponent fiber consisting of a polypropylene core and a polyethylene casing.

Namely, polyethylene has a lower melting point than polypropylene, whereby heating the bicomponent fiber to a temperature higher than the melting point of polyethylene but lower than the melting point of polypropylene means that the polyethylene component melts while the polypropylene component remains unaffected. As a result, the polyethylene component acts as a binder for stabilizing the batt, and no other special binder needs to be added.

The hydrophilic fibers are preferably viscose fibers.

The mixture itself is suitably homogeneous, but also heterogeneous mixture is conceivable. A preferred fiber wadding has a density of 0.05-0.07 g / cm 3 and a basis weight of about 200 g / m2.

The production of the fiber wadding can take place in a manner known to those skilled in the art, for example by carding or aeration.

The absorbent layer 5 may comprise any absorbent material, for example cellulose fluff pulp in which superabsorbent polymers may be applied. fiber or particulate form.

Figure 3 shows a second embodiment of a diaper according to the invention, which, like the previous embodiment, has a liquid-permeable layer 2, suitably a non-woven fabric, intended to abut a user during use of the diaper.

Below the liquid-permeable layer 2 is arranged an absorbent body 7, which comprises a liquid-receiving layer 4 of the same kind as in the embodiment in Figure 2 and an absorbent laminate 8 arranged below it. . The material layers 9, 10 consist, for example, of tissue layers or other compressed cellulose fiber layers. The absorption layer 11 is preferably made of superabsorbents. The absorption laminate 8 can also be composed in the manner shown in Swedish patent application 8901964-0, ie the number of absorption layers 11 can be more than one and the superabsorbents in the different layers can have different absorption properties. Finally, a liquid-impermeable layer 6 is of the same type as in the embodiment of Figure 2, applied to the side of the absorption body 7 facing away from the user. What has been said otherwise about the liquid-permeable and liquid-impermeable layers 2, 6 in Figure 2 is also applicable to the corresponding layer in Figure 3.

The diaper may in a known manner be provided with fastening means, elastic means or the like, without this affecting the invention, for which reason such features are not shown in the figures. When the invention is applied to incontinence guards, sanitary napkins and panty liners, these can be provided with, for example, means for attachment to underpants, without this also having any significance for the invention.

The following example shows how the properties of the fiber wadding are affected by the mixing ratio between the components included in the wadding.

Example 1 * Fiber waders with different weight percent 20 dtex bicomponent fiber with a polyethylene casing and a polypropylene core and 1.7 dtex viscose fiber, were tested for dry and wet thickness, with low and high load, respectively. The basis weight of the fiber pads was 200 g / m2. The thickness was measured by placing a board with variable load on the dry fiber waders, after which their thickness was read by means of a ruler. The thickness was measured partly at a load of 2.3 g / cm2 and partly at a load of 10.5 g / cm2. The lower load gives only slight compression of the fiber batt and is intended to define an easily measurable starting thickness of the batt.

Thereafter, the fiber waders were soaked in water, which was allowed to drain until no more liquid dripped from the waders, after which the thickness was measured in the same way as for the dry waders. The values given in Table 1 are relative and refer to the thickness of a wet and a dry fiber wadding for the respective amount of viscous and load in relation to the thickness of a dry fiber wadding with low load. 10 15 20 25 30 35 7 465 806 Table 1 Viscosity amount Relative thickness Low load High load [Weight percentage] V / T1 [%] T / Tl [%] V / T1 [%] 0 100 - - 10 94 56 53 15 86 52 48 20 “84 48 39 30 56 43 29 V = Wet fiber wadding Tl = Dry fiber wadding with low load T = Dry fiber wadding Low load = 2.3 g / cm2 High load = 10.5 g / cm2 In order to function as a spacer, the fiber wadding must layer between the liquid-permeable layer and the absorption layer, substantially maintaining its thickness in the wet state when exposed to load. Table 1 shows that for a mixture in the fiber wadding of 10% and 15% viscose, the ratio between dry and wet fiber wadding is essentially the same at the high load. For a mixture of 20% viscose, a slightly worse value is obtained, while on the other hand 30% viscose results in a noticeably worse result.

Example 2 Liquid leakage in the inclined plane was measured for a specimen comprising a fiber wad where the composition was varied between the experiments.

The specimen comprised an outer nonwoven fabric layer which enclosed a fibrous wadding superimposed on an absorbent layer comprising superabsorbents. The absorption layer comprised an upper tissue laminate in which 2.5 g of Aqualic CA W-4 was applied in powder form and a lower tissue laminate in which 2.5 g of Waterlock J 550, also in powder form, was applied. Aqualic CA W-4 and Waterlock J 550 are the designation for commercially available superabsorbents.

The specimen of rectangular shape was laid in its longitudinal direction on an inclined plane. The angle of inclination was 30 ° relative to the horizontal plane. 100 ml of 0.9% NaCl (aq) was added to the upper end of the body for 7 seconds. The amount of unabsorbed fluid was collected at the lower end of the body and weighed.

The results are presented in Table 2.

Table 2 Viscosity amount Liquid leakage [Weight percent] [g] 10 24 20 16 30 1 values in Table 2 were compared with the result of a similar experiment where the viscose fiber was replaced with 15 weight percent polypropylene of 2.2 dtex. The liquid leakage for this specimen amounted to 28 g.

Example 3 Wetting was measured for a specimen comprising a fiber wad having a basis weight of 150 g / m 2 and having a varied composition applied on top of an absorbent layer, which consisted of a tissue laminate in which 5.1 g (W 0.1 g) of Aqualic CA W 4. J Re-wetting is a measure of the amount of liquid released from the specimen when it is loaded. 50 ml of 0.9% NaCl (ag) was added to an area of 1-2 cm 2 of the fiber wadding of the specimen. The specimen was allowed to absorb for 3 minutes, after which five weighted filter papers loaded with a weight of 1800 g were placed on the body for one minute. The filter papers were weighed and the weight gain was noted. The results are presented in Table 30 Table 3 Viscosity amount Reheating [Weight percent] [g] 0 0.9 10 0.4 zo 0.3 30 0.1 The values in Table 3 were compared with the results of a similar experiment where the viscose fibers were exchanged for 15% by weight of poly. propylene of 2.2 dtex. The dehydration of this specimen was 0.1 g.

From the results in examples 1-3, it can be concluded that if the viscosity content is increased, both reduced rewetting and reduced leakage in a sloping plane are obtained. The improvement at 30% viscose is particularly noticeable. However, if the viscosity content is as high as 30% or more, the fiber wadding will collapse in the wet state. its thickness after loading is considerably less than the corresponding thickness of the dry wadding. A weight fraction of 30% viscose in the fiber wadding is therefore not suitable, but the preferred range is 10-20% viscose fibers. Furthermore, it can be stated that a dry fiber wad receives reduced elasticity and resilience when the viscose content is increased. It can be noted that a fiber wad completely free of viscose blend exhibits a superior elasticity compared to a fiber wad comprising viscose fibers.

It has been found that the coarse fibers should suitably be of the coarse size 17 dtex in order for the fibrous cotton to achieve sufficient elasticity and resilience. However, if the coarseness increases greatly 465 806 1 ° over 20 dtex, one certainly gains in resilience and resilience, but the fiber wadding thus obtained is rough and uncomfortable to wear. The fine fibers should be of a thickness of 1.5-2 dtex, because coarser fibers would not give a sufficiently fine capillary system in the fiber wadding.

The invention is not to be considered limited by the exemplary embodiments, but a number of modifications are possible within the scope of the claims.

Claims (12)

10 15 20 25 30 35 M 465 sne 'Patent claim Absorbent body (3, 7) for use in a disposable absorbent article such as a diaper, an incontinence guard, a sanitary napkin, a panty liner or the like comprising a fiber wadding (4), which in use is arranged to lie between the user's body and an absorbent layer (5, 8) of the absorbent body for rapidly transporting liquid discharged by the user towards the absorbent layer and for preventing absorbed liquid from coming into contact with the skin of the wearer, characterized in that the fibrous wadding (4) comprises a mixture of coarse fibers of at least 17 dtex coarse and fine fibers of not more than 2 dtex coarse, and of which the fiber wadding (4) is 80-90% by weight of coarse fibers and 10-20% by weight of fine fibers. Absorbent body according to claim 1, characterized in that the coarse fibers are of 20 dtex thickness and the fine fibers are of 1.7 dtex thickness. Absorbent body according to Claim 1 or 2, characterized in that the fiber batt (4) consists of 85% by weight of coarse fibers and 15% by weight of fine fibers. Absorbent body according to one of Claims 1 to 3, characterized in that the coarse fibers consist of hydrophobic, heat-digestible fibers, that the fine fibers consist of hydrophilic fibers and that the fiber wadding (4) is thermobonded. Absorbent body according to claim 4, characterized in that the coarse fibers consist of polyethylene fibers, polypropylene fibers, polyester fibers, bicomponent fibers or mixtures thereof and that the fine fibers consist of viscose fibers. Absorbent body according to claim 5, characterized in that the fibrous wadding (4) comprises bicomponents of the composition - a polypropylene / polyethylene, polyester / polyester or polyester / polyethylene. 7. An absorbent body according to claim 6, characterized in that the bicomponent fibers consist of a core of polypropylene and a sheath of polyethylene. Absorbent body according to one of the preceding claims, characterized in that the absorbent body (3, 7) comprises an absorbent layer (5, 8) arranged in direct contact with the fibrous cotton wool (4), on the side of the fibrous cotton wool (4). 4) which is intended to be turned away from a user. Absorbent body according to claim 8, characterized in that the absorbent layer (5, 8) has a finer capillary system than the nonwoven (4), whereby the liquid passing through the nonwoven (4) can be absorbed in the absorbent layer (5). , 8). Absorbent body according to claim 8 or 9, characterized in that the absorbent layer (5, 8) consists of at least two liquid-transporting material layers (9, 10) and comprises superabsorbent materials. Absorbent body according to claim 10, characterized in that the superabsorbent material is arranged in a layer (11) between two liquid-transporting material layers (9, 10). Absorbent body according to Claim 10 or 11, characterized in that the material layers (9, 10) consist of tissue, cellulose fiber, perforated plastic or non-woven fabric. hrs