MXPA04006707A - Non-woven fabric and absorbent article. - Google Patents

Abstract

The present invention describes a non-woven fabric (1) comprising a plurality of entangled fibers that form a mixture of fibers having three or preferably four type of fibers (2, 2', 3, 3', 4, 4', 5, 5'), the same embodying different denier values from each other, the difference between two consecutive denier values being lower than a unit. The non-woven fabric (1) includes properties of softness and absorption/capture of fluid and softness at an effective manufacturing cost. The invention also refers to an absorbent product such as a sanitary feminine towel, which is provided with the non-woven fabric (1) of the present invention.

Description

A NON-WOVEN FABRIC AND AN ABSORBENT PRODUCT FIELD OF THE INVENTION The present invention is directed to a nonwoven fabric having fibers of varied and distinct lengths, which are preferably designed for use in an absorbent product, such as a feminine sanitary napkin, as well as an absorbent product provided therewith.

DESCRIPTION OF THE PREVIOUS TECHNIQUE As is widely known, an absorbent product such as, for example, a feminine sanitary napkin, comprises a lower layer of impermeable material which is associated with the wearer's undergarment and an upper layer of permeable material which faces the crotch of the wearer, the two layers envelop an absorbent element or core. In the commonly known absorbent products, the upper layer of permeable material can generally show two different configurations, each providing advantages and disadvantages that are: First configuration: the upper layer is composed of a waterproof plastic film provided with holes that allow Exudates from the body are transferred to the core of absorbent material.

Advantageously, this system presents a high performance in the sense of preventing the fluid of the absorbent core from flowing into the lower layer while the wearer is using the sanitary napkin, thus making it possible to keep her body dry until it is exchanged for another unused sanitary napkin . The great disadvantage of this type of cover is the plastic sensation of the upper layer and the feeling of overheating that it gives, which can be unpleasant for a large part of the potential users. - Second configuration: the top layer is composed of a fabric made of a nonwoven material composed of fibers or filaments preferably made of polymeric material, joined together by means already known to those skilled in the art such as, for example, bonded thermal, linked by spinning, linked through air, spinning interlacing, among others. In order to present the desired performance, the fabrics must have a number of mechanical properties, such as a slim comfortable structure, the ability to remain in contact with the skin for long periods without causing any allergies as well as the ability to carry the exudates from the skin. body towards the absorbent core. The great advantage of this type of construction is that the feeling of the upper layer is smoother and smoother than that of the upper layer in the form of a perforated plastic film, providing the absorbent product with a smooth character. The main disadvantage is the fact that this type of top layer is much less efficient than that of the perforated plastic film for the purposes of preventing the body exudate from flowing from the absorbent core towards the wearer's skin. In the construction of the upper layer made of non-woven fabric, conventionally synthetic fibers are used such as, for example, polypropylene, polyethylene, polyester or the like, the used fibers preferably having a denier of 3 (or titles) thus provide the fabric finished with a great softness but, on the contrary, with a great tendency to retain more liquid exudate than is desirable in view of the capillarity provided by its fibers. First, it should be noted that the denier, or title, is a measurement that corresponds to the mass of nine thousand meters of fiber in grams. In the case where the denier of the fibers increases, their ability to retain fluid decreases, which is an advantage but, on the contrary, the finished fabric presents a less smooth and less smooth feeling. In an attempt to solve this problem, BR 9701974-7 of the applicant describes a non-woven fabric having fibers of different lengths (said fibers will be referred to hereinafter as multi-length fibers), an absorbent article and a towel female sanitary ware, the non-woven fabric being composed of a network of matted thermoplastic multi-length fibers, said fibers having a length that varies from around 2 mm to 100 mm, the difference in length between them being at least 2 mm. The preferred embodiment of the fabric described herein is composed of fibers having different lengths between about 15 and 40 millimeters, preferably having between 2 and 6 different lengths and preferably having two different denier values, preferably between 2 and 5. The document also states and claims that it is advantageous that the difference in the denier values of the fibers used in the fabric is at least one unit, and preferably two units, one related to the other. This derives from the fact that it is difficult to simultaneously produce fibers with lower denier variations to make the final fabric. Preferably, the finished non-woven fabric has a strength of about 35 g / m2, a configuration where a much greater softness is obtained than that exhibited by the non-woven fabric composed of only one type of fiber, and its ability to retain fluids as well. it decreases considerably, increasing the feeling that the sanitary towel is always dry. As an inherent characteristic of this modality, the same solidity, the thickness obtained in the composite fabric of multi-length fibers with a variation in the denier value of the fibers is greater than the thickness of (i) a composite fiber fabric. of a single length and only a denier value, (ii) a fabric composed of fibers of a single length and several denier values, and (ii) a composite fabric of multi-length and only a denier value. A second relevant technique of the prior art is one related to the US patent. No. 6,087,551 of the same Applicant as herein and very similar to the first one, wherein a non-woven fabric composed of entangled thermoplastic multi-denier fibers provides a homogeneous mixture of high and low denier fibers, the denier values exhibited by the fibers of denier high and low denier fibers varying by at least one unit. The fabrics described by the two prior art techniques have a number of advantages compared to the non-woven fabric composed of only one type of fibers, however, whereby the properties of softness and low tendency to fluid retention are achieved.; it is necessary that the solidity exhibited by them be within a range of 35 g / m2. This value, however, considerably increases the manufacturing cost of this non-woven fabric, being a prohibitive option in those countries where the purchasing power of the majority of the population is small, in view of the fact that the final price of a sanitary towel made of the same thing is too high, thus restricting its penetration in the consumer market. In order to reduce the manufacturing cost of the non-woven fabric, it is possible to reduce its solidity, however, the property of softness is lost and the fabric begins to show a poor appearance and an excessively reduced thickness. A non-woven fabric has not been developed to date, particularly for use in sanitary products such as a feminine sanitary napkin, which is provided with multi-length fibers having various denier values and is provided with softness, volume, low capacity of fluid retention and a low manufacturing cost, in such a way that the absorbent product made of it can be commercialized at a reduced cost, increasing its competitiveness, notably in countries where the majority of the population has a low purchasing power .

OBJECTS OF THE INVENTION The object of the present invention is to provide a non-woven fabric, particularly for use in an absorbent product, comprising a plurality of fibers having at least two different lengths, the fibers of each length having at least three different denier values , in such a way that it presents a high softness and low fluid retention at a lower solidity than that required by the existing fabrics, as well as a reduced manufacturing cost. Another object of the present invention is to provide an absorbent product comprising the aforementioned nonwoven fabric.

BRIEF DESCRIPTION OF THE INVENTION The objects of the present invention are achieved with a nonwoven fabric composed of a plurality of entangled fibers that form a mixture of fibers, the fiber mixture comprising at least a first, a second and a third types of different fibers that present different denier of one another, the difference between consecutive denier values being lower than unity. Also, the objects of the present invention are achieved with an absorbent product, particularly for the absorption of body exudates, provided with at least one lower layer made of a waterproof material that is facing the wearer's clothing and at least one upper layer facing the body of the user, both the lower layer and the upper layer enveloping an absorbent element, the upper layer being composed of a nonwoven fabric comprising a plurality of entangled fibers forming a mixture of fibers, which it comprises at least a first, a second and a third types of different fibers that have different denier from one another, the difference between the consecutive denier values being lower than the unit. The present invention advantageously makes it possible for the finished nonwoven fiber: · to have a lower solidity than the solidity exhibited by the non-woven fabrics of the prior art, which means a lower manufacturing cost in view of the use of less material; • shows an increased coverage power, even with a reduction in strength, compared to prior art fabrics, so that the appearance of the fabric is good without giving the impression that it is too "thin"; • present an increase in the number of fibers in the fabric, providing a better softness. In this sense, it should be noted that the greater the number of fiber tips in the fabric, the greater will be the sensation of softness that transmits to each person who handles it. The highest softness is an important sales argument, since it can increase the penetration of an absorbent product made of a fabric now launched in the market. The increase in the surface area of the fibers in relation to their volume (in view of the higher number of existing tips) increases the capacity to store / transport fluids, providing the fabric with a better performance in the rewet test compared with the non-woven fabrics of the prior art.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described in greater detail on the basis of a practical example shown in the drawings. The figures show: Figure 1 - a schematic view of the manufacture of the first, second, third and fourth types of fibers that constitute the nonwoven fabric object of the present invention; Figure 2 - a schematic view of the equipment for cutting fibers and the finished fibers obtained after they are cut; and Figure 3 - a schematic view of the nonwoven fabric object of the present invention.

Figure-4 illustrates the good performance of the fabric of the present invention in the rewet test.

DETAILED DESCRIPTION OF THE FIGURES According to a preferred embodiment and as can be seen from Figure 1, the non-woven fabric 1 object of the present invention is composed of a plurality of entangled fibers 2, 2 ', 3, 3', 4, 4 ', 5, 5'. Preferably, these fibers are made of polymeric material such as, for example, polypropylene, polyethylene, polyester, polyacrylate, mixtures thereof or the like, fibers of two components as well as any other required or desired material, since the present invention is not the type of material used in the fiber. Preferably, polyethylene fibers are used. Regardless of the type of fibers used, they are entangled by a number of technologies known to those skilled in the art such as, for example, the processes of carding and ligation, thermal bonding, spun bonding, laying in air, interlacing by spinning and hydro-spinning, among others. Again, it should be noted that the method used to bind the fibers can be any process, since this is not the subject of the present invention and, for this reason, will not be described here. The nonwoven fabric 1 object of the present invention comprises a plurality of entangled fibers 2, 2 ', 3, 3', 4, 4 ', 5, 5' forming a mixture of fibers provided with at least three, but preferably four, types of fibers, namely: • a first type of fiber (2,2 ') presenting a first denier; • a second type of fiber (3,3 ') that has a second denier that is higher than the denier of the first type of fiber; • a third type of fiber (4,4 ') that has a third denier that is higher than the denier of the second type of fiber; • a fourth type of fiber (5.5 ') that presents a fourth denier that is higher than the denier of the third type of fiber. It should be noted, as already mentioned here, that the denier, or title, is the unit that corresponds to the mass of nine thousand meters of fiber, in grams. The main innovative feature of the present invention, in addition to the existence of three, four or more types of different fibers having different denier values, lies in the fact that the consecutive denier values (i.e., when comparing the first and second denier values, the second and third denier values, and the third and fourth denier values) show a difference of less than one unit, a feature that provides a number of advantages to the finished fabric, as will be explained in more detail more ahead. In the preferred embodiment of the present invention, the fibers of the first type (2,2 ') have a denier of 2.3 (two point three), the fibers of the second type (3,3') have a denier of 3.2 (three point two), the fibers of the third type (4,4 ') have a denier of 3.8 (three point eight) and the fibers of the fourth type (5,5') have a denier of 4.0 (four point zero). As can be seen, the consecutive denier values are always less than 1, which is a requirement for the present invention. As already mentioned before, the use of fibers having low denier values provides the finished fabric with a greater softness of tact and flexibility. This occurs because the fibers thus configured have a lower thickness and therefore there is a large amount of fibers in the same area of the fabric. This feature also makes it possible for the finished fabric to have a high coverage power (which results in a thicker or thicker fabric appearance), which is measured by the number of fibers per square centimeter of fabric. However, in view of the increased coverage power, this fabric has reduced interstitial gaps between the fibers, thus showing a high capillarity which implies an undesirably high capacity to absorb and retain fluids. As a result, the fabric exhibits poor performance when it is subjected to tests to verify the percentage of fluids it releases when it is compressed, sometimes after it has absorbed said liquid. These tests are called rewet tests and their result is very important because an absorbent product (such as a sanitary napkin) that comprises a fabric that shows poor performance in the test, gives the user the feeling that it is wet, evidencing so the product does not present a good performance and is not able to prevent body exudates from escaping from it. On the other hand, the use of fibers having high denier values provides the finished fabric with little softness of touch and flexibility and, on the contrary, a low capacity to absorb and reduce fluids, which is desirable. This occurs because the fibers of a high denier have a high thickness and, therefore, there is a considerably lower amount of fibers in the same area of the fabric than if the fibers had a lower denier. As a result of using fibers with a higher denier, the finished fabric has a lower coverage power, which, as already mentioned here, corresponds to the regime of the number of fibers per square centimeter of fabric. Since the coverage power is lower, a fabric configured in this manner has several considerable interstitial gaps between the fibers, in such a way that its capacity to absorb and retain fluids is low (in view of the reduced capillarity) and the results that achieved in the rewet tests are very favorable. As a great disadvantage of the use of the fabric made of high denier fibers, there is the fact that the sensation of the product is not pleasant and smooth and its appearance is very poor, since the large interstitial gaps give the impression that the Fabric is of poor quality and too thin. The increased softness and the low capacity to absorb and retain fluids are therefore conflicting properties.

Since the nonwoven fabric object of the present invention is composed of four types of fibers having different denier values, it is possible to obtain the softness and reduced capacity of absorption and retention of fluid properties, wherein the fibers of the first type ( 2,2 ') and the second type (3,3') cooperate so that the fabric presents softness, flexibility and soft feeling, while the fibers of the third type (4,4 ') and the fourth type (5,5'). ') cooperate so that the fabric has a lower capacity for absorbing / retaining fluids (exudates from the body). The result is a new non-woven fabric that, in addition to presenting a lower capacity to absorb / retain, is provided with a soft flexible sensation greatly increased that is noticed by those who manipulate it, thus obtaining a great advantage compared to the non-woven fabrics that are currently commercially available at a reduced manufacturing cost. And, as a further advantage, it should be noted that these properties can be achieved by a fabric having a minimum solidity of approximately 18 g / m2 (and can even reach approximately 35 g / m2) while other non-woven fabrics of the prior art , in order to exhibit a low capacity to absorb / retain exudates from the body and a satisfactory smoothness, they required a strength of approximately 25-35 g / m2, which makes them much more expensive than the fabric described here (which may present a result similar in spite of having a reduced solidity). Another great advantage of the fabric described herein can be easily noticed when compared to non-woven fabrics that are currently commercially available at a low cost. First of all, it should be noted that the cost of manufacturing and marketing a non-woven fabric is not directly associated with its solidity because, the higher its value, the greater the amount of fibers required to manufacture them, in such a way that, evidently, its manufacturing cost will be higher if compared with a fabric that has a lower solidity. In this way, the fabric can have a greater number of fibers per unit area, each fiber must have a lower volume, that is, it must occupy a smaller space and, for this to be feasible, the fiber must have one more denier. low. A fabric configured in this way has a great softness. However, a fabric provided with many fibers of a low denier has only a few interstitial voids between the fibers, and its ability to absorb / retain liquids increases in view of the capillary phenomenon. In order to reduce the number of fibers used and, as a result, the cost of manufacturing the fabric, it is necessary to increase the denier of the fibers. In doing so, the finished fiber begins to show a reduced capacity to absorb / retain fluids, but becomes coarse and lacks softness. However, in consumer markets where the purchasing power of the population is low, these fabrics are reduced in the upper layers of absorbent products, regardless of the problem of lack of softness. Therefore, the fabric described herein has a great advantage over existing fabrics having higher denier fibers, ie, they have a much higher softness and a lower capacity to absorb / retain liquids, thus maintaining the manufacturing cost substantially equivalent to them. However, it is evident that the denier of the first, second, third and fourth fiber types can assume other values different from 2.3, 3.2, 3.8 and 4.0, in accordance with the needs of what is desired that is required for the fabric, provided that it is within the scope of protection of the appended claims. The preferred denier values are between 1 and 6, most preferably between 2 and 6, the values of the preferred embodiment being only one possibility. The only requirement is that the fabric can have at least three types of different fibers, whose consecutive denier values have a difference lower than unity. A fiber made of polymeric material that can be manufactured through the extrusion process, wherein the polymeric material 6 is placed in an extrusion equipment 10 provided with an endless screw (or other similar element) 7 and heated until melted . The worm 7 pushes the polymeric material 6 and urges it to pass through at least one spinner 8 provided with a plurality of openings or holes that is like a large screen, and then this polymeric material takes the form of filaments which, after leaving spinner 8, is cooled to room temperature. The filaments correspond to the fibers 2,2 ', 3,3', 4,4 ', 5,5' and the denier thereof is directly related to the diameter of the holes and the flow velocity of the polymer mass melt being dosed to said spinner 8, through a pump to supply molten polymer (not shown). Then, the fibers are cut into predetermined lengths that are obtained through different cuts, in a piece of equipment for cutting fibers (generically shown in figure 2 by reference number 9). This means that the extrusion equipment 10 produces fibers of only one size which are then cut into one or more desired lengths. Conventionally, an extrusion equipment 10 is provided with two spinners connected in series 8, such that both are fed in a homogeneous manner and therefore the quantity of fibers produced by the two spinners 8 in the same time interval. It does not matter. In the case that the flow rates of the supply pump of the two spinners 8 are the same, the resulting fibers of the two spinners will have the same denier, that is, their mass, in grams, for a length of nine thousand meters, it will be the same. Therefore, half the mass of polymeric material is converted into fibers in each spinner 8. However, when the flow rates of the supply pumps of the two spinners are different from each other, said equivalence no longer exists, since in view of this change in flow rates, each spinner will produce fibers that have different denier values. Therefore, the equivalence of the same mass percent of the polymeric material, which has been converted into fibers in each spinner, will no longer take place, and a proportionality relation will occur instead. The spinner that produces fibers with a higher denier (due to the higher flow rate of the supply pump) converts a larger mass percent of the polymeric material into fibers than the mass percent obtained by the spinner that has a supply pump with a lower flow velocity, despite the fact that the amount of fibers produced in each of them is the same. Therefore, when using this conventional production method, it is impossible to produce fibers having more than two different types of fibers and, due to economic issues, it is not likely to produce fibers having very similar denier values at the same time. In addition, the properties of a fabric provided with only two types of fibers having the same denier (ie, less than one unit of each other) do not differ to a high degree from those presented by the fabric provided with at least one type fiber, which can also provide a much lower production cost. It should be noted that the manufacturing companies use standard fiber types so denier fibers that show a variation of less than one unit one of another can not be found in the market, so it is possible to manufacture a fabric nonwoven using four types of fibers that have different denier values, as long as the rule that the difference between two consecutive denier values must be lower than one unit is maintained. The manufacture of a nonwoven fabric object of the present invention is only possible when using an extrusion equipment 10 provided with at least three, and preferably four, spinners 8 connected in series. Since the flow rates of the pumps of each spinner 8 have different values, three or preferably four different fiber types can be obtained, each of them having a particular denier value. In the case of the preferred embodiment in which the fibers of the first type (2.2 ') have a denier of 2.3, the fibers of the second type (3.3') have a denier of 3.2, the fibers of the third type (4). , 4 ') have a denier of 3.8 and the fibers of the fourth type (5.5') have a denier of 4.0, the mass ratios of each type of fiber produced, and consequently presented by the non-woven fabric 1 object of this invention, are 18.54% for the fibers of the first type (2.2 '), 23.84% for the fibers of the second type (3.3'), 27.81% for the fibers of the third type (4.4 ') and 29.85% for the fibers of the fibers of the fourth type (5.5 '). In this mode, the average denier value is 3.43. Advantageously, all fibers having the same denier represent approximately 10% to 90% of the total fibers in the mixture, most preferably still between 10% and 40% of the total. Therefore, as already mentioned before, the non-woven fabric constructed in accordance with the teachings of the present invention has a high softness and a lower capacity to absorb and retain liquids. However, in order to further improve both properties, fibers having different lengths are used, preferably fibers having from two to fifteen different lengths and very particularly two to six different lengths. To achieve advantageous results, the fibers must have a length between about 10 millimeters and 80 millimeters, each length being at least about 4 millimeters different from each other. Preferably, the fibers have lengths ranging from approximately 15 millimeters to 40 millimeters, the value of the difference between the two being maintained. In the preferred embodiment of the fabric 1 object of the present invention, eight different fibers are used, as follows: · a plurality of fibers of the first type having a denier of 2. 3 and a length of about 30 millimeters (numbered as 2) and a plurality of fibers of the first type having a denier of 2.3 and a length of about 40 millimeters (numbered as 2 '). • a plurality of fibers of the second type having a denier of 3.2 and a length of about 30 millimeters (numbered as 3) and a plurality of fibers of the second type having a denier of 3.2 and a length of about 40 millimeters (numbered as 3'). • a plurality of fibers of the third type having a denier of 3.8 and a length of about 30 millimeters (numbered as 4) and a plurality of fibers of the third type having a denier of 3.8 and a length of about 40 millimeters (numbered as 4'). • a plurality of fibers of the fourth type having a denier of 4.0 and a length of about 30 millimeters (numbered as 5) and a plurality of fibers of the fourth type having a denier of 4.0 and a length of about 40 millimeters (numbered as 5'). When analyzing in an inverted manner, it can be said that fibers having four different denier values are used for each fiber length value. Of course, the values of the lengths may vary, and may even be different from the values referred to as the preferred ranges, depending on the convenience and / or necessity when they are manufactured. In order to maximize the desired properties of the fabric, the fibers 2,2 ', 3,3', 4,4 ', 5,5' must have a thickness between approximately 0.15 millimeters and 0.40 millimeters. In this regard, it should be noted that, as can be understood from the previous explanations, the thickness values of the fibers 2,2 ', 3,3', 4,4 ', 5,5' are determined by the flow rate of the supply pump of each of the spinners 8. Finally, it should be remembered that measurements of length, denier and thickness of a fiber are average values and there will certainly be a wide variation of values around them.

The non-woven fabric 1 of the present invention is used as the top layer of an absorbent product, such as a feminine sanitary napkin, a means of protecting the breast during lactation, disposable diapers or the like. As already mentioned herein, an absorbent product comprises a lower layer made of impermeable material that is associated with the wearer's undergarment and an upper layer made of permeable material that faces the wearer's crotch, the two layers wrapping a Absorbent element or core. Particularly in relation to feminine sanitary napkins, the covering capacity of the upper layer fabric, in relation to menstrual fluids, is considered to be an aspect of great importance. Therefore, an object here is to provide an upper layer, the fabric of which it is made enables the exudates of the body to flow therethrough to the absorbent material, thus keeping the minimum of fluid in the interstitial recesses of the body. and prevents the clear and vivid view of the exudate that has just been absorbed. To achieve this, preferably the fibers of the non-woven fabric are provided with a dry material, preferably white in color such as, for example, titanium dioxide (??? 2), calcium carbonate (CaCO3) and mixtures thereof , the first being the most preferred dye. Preferably, the amount of? 2 used is in the range of 1% to 6% by weight, most preferably between 2% and 3.5% by weight. In addition, to ensure that the fabric of the top layer remains hydrophilic after some time of being in contact with the wearer's skin and fluid flow, a hydrophilic agent is used, particularly a nonionic surfactant such as sodium salts. of dioctyl sulfosuccinate, nonionic polyoxyethylene sorbitan monolaurate or even another functional agent. The way in which this agent impregnates in the fabric can also be any, as long as it is functional. The lower layer, in turn, is made of a suitable fluid impermeable material, polyethylene or polypropylene being preferably used in the form of a film, however it may be gas permeable in order to improve ventilation in the region where it is located the absorbent product. Except for the top layer, all the characteristics of the absorbent product may vary, as necessary or desirable. Preferably, the absorbent product is a feminine sanitary napkin, but can adopt any configuration such as, for example, the breast protectors during lactation and the diapers already mentioned herein. In order to corroborate the advantages of the non-woven fabric object of the present invention, and as a consequence, those of the absorbent product comprising same (which is itself an object of the present invention as well), both have been compared with the respective fabric and absorbent product of the prior art, as can be seen in the following tables.

TABLE 1 Fabric of 25 q / m2 - difference between two consecutive denier values less than one unit Non-woven fabric described here: number of fibers / cm2 - denier function and length TABLE 2 TABLE 3 Fabric of 25 q / m2 of the prior art (difference between the values of consecutive denier equal to one unit) Prior art nonwoven fabric: number of fibers / cm2 - denier function and length Denier (%) 3.0 5.0 Length (%) 50% 50% Tests A B C A B C 10 mm 28 - - 28 - - 20 mm 28 30.6 - 28 30.6 - 30 mm 28 30.7 40 28 30.7 40 40 mm 28 30.7 40 28 30.7 40 Fibers / cm 1 12 92 80 1 12 92 80 length / denier TABLE 4 As can be seen when comparing tables 1, 2, 3 and 4, the fabric does not woven object of the present invention presents a number of characteristics advantageous in relation to the fabric of the prior art, namely: • the decrease in the denier values of the fibers used causes the fabric described here to have a lower solidity than the solidity presented by the fabrics of the prior art, which means costs of minor manufacturing in view of the economy with respect to the material; • the increase in the number of fibers per unit area of the fabric described here provides the same with a higher coverage power, even with a reduction in the solidity, in comparison with the fibers of the prior art, in such a way that the appearance of the fabric is good, without impression of being too "thin"; • in view of the fact that the denier of the fibers used in the fabric described herein is lower, there is an increase in the number of fibers in the fabric, obtaining the aforementioned higher covering power. With this in mind, the number of fiber tips is also higher, which provides greater softness. In this sense, it should be noted that the soft feeling given by the fabric is directly associated with the number of tips of the fiber that penetrate the pores of the skin of the person who handles it. This penetration is translated as softness. The greater the amount of fiber tips in the fabric, the greater the feeling of softness that it gives to the person who handles it. The greater softness is an important sales argument, and can increase the penetration of an absorbent product provided with the fabric described here in the market; • the increase in the surface area of the fibers in relation to their volume (in view of the higher number of existing tips) decreases the capacity to retain / transport fluids due to the reduction in capillarity, thus providing the fabric with a better performance in the re-measurement test. Still with respect to the performance of the fabric described herein, Figure 4 illustrates its good performance in the aforementioned rewet test (to be explained later). The fabric 1 corresponds to a top layer of sanitary napkin having 30 g / m2 of solidity consisting of 3 and 5 denier fibers. The fabric 2 corresponds to a top layer of sanitary napkin having 25 g / m2 of solidity consisting of fibers of 2.3 and 4 denier.

The fabric 3 corresponds to a top layer of sanitary napkin having 16 g / m2 of solidity consisting of 1.3 denier fibers. The fabric object of the present invention that is tested corresponds to the preferred embodiment described herein, that is, it has a strength of 25 g / m2 and consists of fibers with 2.3, 3.2, 3.8 and 4.0 denier. As seen in graph 1, the fabric object of the present invention has a rewet value of 0.07 in the test, which is a very small value and similar to that of the fabric 2 of the prior art which, in turn, presents more poor softness properties, in view of the fact that it consists of fibers having only 2 denier values. The other fabrics of the prior art present a considerably more deficient performance. In that sense, it should be noted that, in a rewet testThe lower the value obtained, the better the performance of the fabric being tested. To conduct a rewet test, a quantity of fluid is emptied into a certain area on the surface of the preweighed nonwoven test fabrics that are laid on a pad of absorbent material. After the fluid flows, the fabrics are removed and weighed. The difference between the respective final and initial weights is taken as the fluid retention. The time elapsed between the start of fluid emptying and the weight of the fabrics is approximately 2 minutes. The backflow of the fluid is measured by means of absorbent material sponges of known masses which are compressed on the fabrics for a determined period. The mass of fluid absorbed by each sponge is taken as the backflow of the fluid.

Analytical data: - Fluid used: synthetic menstrual fluid, as mentioned in WO9510996, page 37. - Amount of fluid emptied: 7 ml. - Area defined on the surface of the test fabrics: oval holes (3.9 cm x 2.6 cm) of an acrylic plate of 27 cm x 1 1 cm x 7.5 cm that has a mass of 276.4 g that is laid on the fabrics during the proof. - Pad of absorbent material: bleached pulp of long wood fibers, whose dimensions are 210 mm x 55 mm x 12 mm and the density is 0.06 g / cm3. - Emptying the fluid: only once and quickly. Absorbent sponge: 7.5 cm x 7.5 cm of extra-absorbent tablet, manufactured by Johnson & Johnson Industrial Ltda. - Application of the pressure: five minutes after the fluid has penetrated the pads of absorbent material, they are placed on a hard flat surface. Two sponges folded in four parts are placed on damp spots. A standard weight of 2.2 kg (dimensions of 5.1 cm x 10.2 cm x 5.4 cm) is placed horizontally on the sponges (lying on the surface of 5.1 cm x 10.2 cm), generating a pressure of approximately 4.14 kPa. The weight is removed three minutes later, as well as the sponges, which are weighed immediately. The difference in weight of the sponges before and after the absorption of fluid is the backflow of the fluid. Having described a preferred exemplary embodiment, it should be understood that the scope of the present invention encompasses other possible variations, being limited only by the wording of the appended claims where possible equivalents are included.

Claims (10)

NOVELTY OF THE INVENTION CLAIMS

1. - A nonwoven fabric composed of a plurality of entangled fibers forming a fiber mixture, wherein the fiber mixture comprises at least one first, second and third types of fibers (2, 2 ', 3, 3', 4) , 4 ', 5, 5') that have different denier values from each other, the difference between the consecutive denier values being lower than one unit.

2. The fabric according to claim 1, further characterized in that the first type of fiber (2,2 ') has at least a first length and a second length different from the first, the second type of fiber (3, 3 ') has a first length and a second length different from the first and the third type of fiber (4,4') has at least a first length and a second length different from the first.

3. The fabric according to claim 1, further characterized in that it comprises first, second, third and fourth types of fibers that have different denier values from each other, the difference between the consecutive denier values being lower than one unit .

4. The fabric according to claim 3, further characterized in that the fourth type of fiber (5.5 ') has at least a first length and a second length different from the first.

5 - . 5 - The fabric according to claim 4, further characterized in that the first, second, third and fourth fiber types having the first length (2, 3, 4, 5) have different denier values from each other, the difference between the denier values of these fibers being lower than one unit, and the first, second, third and fourth types of fibers having the second length (2 ', 3', 4 ', 5') have different denier values from one another, the difference between the consecutive denier values being lower than one unit.

6. - The fabric according to claim 5, further characterized in that the denier values of the first, second, third and fourth type of fibers (2, 2 ', 3, 3', 4, 4 ', 5, 5' ) vary between 1 and 10, most preferably between 2 and 6 and most preferably between 2.3 and 4.0.

7. - The fabric according to claim 6, further characterized in that the first type of fiber (2.2 ') has a preferred denier of 2.3, the second type of fiber (3.3') has a preferred denier of 3.2. , the third type of fiber (4,4 ') has a preferred denier of 3.8 and the fourth type of fiber (5,5') has a preferred denier of 4.0.

8. - The fabric according to claim 6, further characterized in that the preferred value of the first length is about 10 millimeters and the value of the second length is about 80 millimeters, and most preferably the value of the first length is of approximately 305 millimeters and the length of the second value is approximately 40 millimeters.

9. - The fabric according to claim 8, further characterized in that the first type of fiber (2,2 ') preferably represents approximately 10% to 90% of the total fibers in the fiber mixture and most preferably represents from 10% to 40%. % of the total.

10. The fabric according to claim 8, further characterized in that the second type of fiber (3,3 ') preferably represents approximately 10% to 90% of the total fibers in the fiber mixture and most preferably represents 10% to 40% of the total. 1. The fabric according to claim 8, further characterized in that the third type of fiber (4,4 ') preferably represents approximately 10% to 90% of the total fibers in the fiber blend and most preferably represents 10%. % to 40% of the total. 12. - The fabric according to claim 8, further characterized in that the fourth type of fiber (5.5 ') preferably represents approximately 10% to 90% of the total fibers in the fiber mixture, and most preferably represents 10%. % to 40% of the total. 13. - The fabric according to claim 1, characterized in that it has a preferred strength between 18 and 35 grams per meter. 14. An absorbent product, particularly for the absorption of exudates from the body, provided with at least one lower layer made of a waterproof material that faces the user's undergarment and at least one upper layer facing the front. to the user's body, both the lower layer and the upper layer wrapping an absorbent element, wherein the upper layer is composed of a non-woven fabric comprising a plurality of entangled fibers forming a fiber mixture comprising at least a first , a second and a third fiber types (2, 2 ', 3, 3', 4, 4 ', 5, 5') that have different denier values from each other, the difference between the consecutive denier values being more Under that one unit. 15. The absorbent product according to claim 14, further characterized in that the first type of fiber (2,2 ') has at least a first length and a second length different from the first, the second type of fiber (3). , 3 ') has at least a first length and a second length different from the first, and the third type of fiber (4,4') has at least a first length and a second length different from the first. 16.- The absorbent product in accordance with the claim 14, further characterized in that the nonwoven fabric comprises a first, second, third and fourth fiber types having different denier values from each other, the difference between the consecutive denier values being lower than one unit. 17 - The absorbent product in accordance with the claim 16, further characterized in that the fourth type of fiber (5.5 ') has at least a first length and a second length different from the first. 18. The absorbent product according to claim 17, further characterized in that the first, second, third and fourth types of fibers having a first length (2, 3, 4, 5) have different denier values from each other, the difference between the denier values of these fibers being lower than one unit; and the first, second, third and fourth fiber types having the second length (2 ', 3', 4 ', 5') have different denier values from each other, the difference between the consecutive denier values being lower than a unit. 19. - The absorbent product in accordance with the claim 18, further characterized in that the denier values of the first, second, third and fourth fiber types (2, 2 ', 3, 3', 4, 4 ', 5, 5') vary between 1 and 10, most preferably between 2 and 6 and most preferably still between 2.3 and 4.0. 20. - The absorbent product in accordance with the claim 19, further characterized in that the first type of fiber (2,2 ') has a preferred denier of 2.3, the second type of fiber (3,3') has a preferred denier of 3.2, the third type of fiber (4,4 ') ') has a preferred denier of 3.8 and the fourth type of fiber (5.5') has a preferred denier of 4.0. 21. - The absorbent product according to claim 19, further characterized in that preferably the value of the first length is about 10 millimeters and the value of the second length is about 80 millimeters, and most preferably the value of the first length it is approximately 30 millimeters and the value of the second length is approximately 40 millimeters. 22. The absorbent product according to claim 21, further characterized in that the first type of fiber (2,2 ') preferably represents approximately 10% to 90% of the total fibers of the fiber blend, and most preferably represents 10% to 40% of the total. 23. - The absorbent product according to claim 21, further characterized in that the second type of fiber (3,3 ') preferably represents approximately 10% to 90% of the total fibers of the fiber mixture, and most preferably represents 10% to 40% of the total. 24. The absorbent product according to claim 21, further characterized in that the third type of fiber (4,4 ') preferably represents approximately 10% to 90% of the total fibers of the fiber blend, and most preferably represents 10% to 40% of the total. 25. - The absorbent product according to claim 21, further characterized in that the fourth type of fiber (5.5 ') preferably represents approximately 10% to 90% of the total fibers of the fiber blend, and most preferably represents 10% to 40% of the total. 26. - The absorbent product according to claim 14, further characterized in that the upper layer of non-woven fabric has a preferred strength between 18 and 35 grams per meter.