MXPA00005451A - Absorbent article - Google Patents

Abstract

Absorbent article such as a diaper, pant diaper, incontinence guard, sanitary napkin, wound dressing or the like comprising a layer of continuous fibers (9), so called tow, which is bonded in points, spots or lines in a bonding pattern (10), but where the fibers otherwise are substantially unbonded to each other. Said layer can either be used as a liquid acquisition layer (5) in the article under the topsheet (2), as a topsheet (12) or as a combined topsheet and liquid acquisition layer (22).

Description

ABSORBENT ARTICLE TECHNICAL FIELD The present invention relates to an absorbent article such as diaper, diaper brief, incontinence protection, sanitary napkin, wound dressing or the like comprising a liquid-permeable top sheet, a waterproof backing sheet to the liquids and an absorbent body placed between these two sheets. BACKGROUND OF THE INVENTION / _ Absorbent articles of the aforementioned type have the purpose of absorbing body fluids such as urine and blood. They usually comprise a top sheet - permeable to liquids, the purpose of which is to face the user during use, in the form of a non-woven material, such as, for example, a spun material. It is also known to incorporate a liquid acquisition layer between the upper sheet and the absorbent body, said liquid acquisition layer having the capacity to rapidly receive large quantities of liquid, distribute this liquid and store it temporarily before its absorption by the absorbent body. underlying. This is especially important in today's thin compressed absorbent bodies often with a large amount of what are known as superabsorbents, which have a high absorption capacity but in many cases an absorption rate too low to be able to momentarily absorb the large amount of fluid that can be discharged for a few seconds when urinating. A relatively thin porous acquisition layer, for example, in the form of a fibrous padding, a carded fiber fabric or another type of fibrous material, has a high capacity for momentary reception of liquids and can temporarily store liquids prior to absorption by liquids. The absorbent body The same applies to foamy porous materials The liquid is then drained successively to the underlying absorbent body, after which the acquisition layer again has the capacity to receive liquid from repeated wetting. Absorbent articles comprising said porous acquisition layer are presented, for example, in US-A-3, 371, 667, EP-A-0, 312, 118 and EP-A-0, 474, 777.

The materials used today as acquisition layers in absorbent articles generally work well but are relatively expensive and can sometimes have an insufficient acquisition time, especially in the second and third wettings if we are talking about large amounts of liquid. It is previously known, through EP-A-0,391,814 and GB-B-2, 209, 672 to employ unbound continuous synthetic fibers, known as tow, to absorb absorbent articles to distribute the liquid in the longitudinal direction from the article. Another problem is that conventional liquid-permeable sheet-like materials used for absorbent articles of this type, usually a synthetic fiber non-woven material, -for example a spun material, often have a lower liquid acquisition rate than the liquid. acquisition layer, wherein the liquid may leak out of the article before it reaches the acquisition layer. The problem can obviously be solved by the use of a top sheet material which is very open and which has a high permeability to liquids. Said open top sheet material can, however, cause problems with too low a resistance and in the sense that the sharp ends of the fibers of the acquisition layer can penetrate into the open top sheet material and irritate the user. OBJECT AND IMPORTANT CHARACTERISTICS OF THE INVENTION The object of the present invention is to offer a material that has a high, acquisition rate for liquid also in the case of repeated wetting, which has a high resistance and resistance to wear, very comfortable and which can be produced at low cost. This has been achieved in accordance with the present invention by offering a continuous fiber layer which is known as tow attached in points or lines in a bonding pattern., but where the fibers, otherwise, are not substantially joined together. The material layer can be used as a liquid acquisition layer under a top sheet material, such as a top sheet material, or as an integrated top sheet / liquid acquisition layer. DESCRIPTION OF THE DRAWINGS The invention will be described more precisely below with reference to some of the embodiments illustrated in the accompanying drawings. Figure 1 is a plan view of an absorbent article in the form of an incontinence protection. Figure 2 is a tran &amp cutversal according to line II-II in figure 1. Figure 3 is a plan view of an absorbent article in the form of a diaper. Figure 4 shows schematically a layer piece of fibrous material according to the invention. Figure 5 shows, at an enlarged scale, a cross-section according to line IV-IV in Figure 3. Figures 6-9 are schematic enlarged cross-section views of four different embodiments of the article in accordance with the present invention. - Figure 10 is a schematic view of a device for demonstrating the acquisition of the liquid of a bent absorbent article as it will be used between the user's legs. DESCRIPTION "'OF THE MODALITIES ~ Figure 1 and Figure 2 schematically show an example of an incontinence guard 1 comprising a liquid-permeable topsheet 2, a liquid-impermeable backsheet 3, and an absorbent body 4 locked in between them. A porous, resilient liquid acquisition layer 5 is placed between the liquid-permeable topsheet 2 and the absorbent body 4. The liquid-permeable topsheet 2 may comprise a nonwoven material such as, for example, a spunbond material. synthetic filaments, a meltblown material, a thermobonded material or a bonded fibrous material bonded together. The liquid-impermeable backing sheet 3 may consist of a plastic film, a nonwoven material coated with a liquid impervious material or a hydrophobic nonwoven material that resists liquid penetration. The top sheet 2 and the back sheet 3 have a greater surface area than the absorbent body 4 and the liquid acquisition layer 3 and extend out from the edges thereof. Layers 2 and 3 are interconnected within the projecting portions as, for example, by glue or by thermal or ultrasonic welding. The absorbent body 4 may be of any conventional type. Examples of common absorbent materials are cellulose fluff pulp, gauze layers, highly absorbent polymers (known as superabsorbents), absorbent foam materials, absorbent nonwoven materials and the like. It is common to combine a cellulose fluff pulp with superabsorbents in an absorbent body. It is also common to have absorbent bodies comprising layers of different materials with different properties in terms of the liquid acquisition capacity, liquid distribution capacity and liquid storage capacity. This is well known to one skilled in the art and does not require detailed description here. The thin absorbent bodies that are frequent as in the case of baby diapers and incontinence protections often consist of a mixed structure or compressed layers of cellulose fluff pulp and superabsorbent. On the outside of the liquid-impermeable backing sheet 3, fastening means in the form of strips 6 of a self-adhesive glue are placed. An incontinence protection of the type illustrated in Figure 1 is primarily intended to be used by people suffering from relatively mild incontinence and can be easily used in custom briefs. The fastening means 6 serves to maintain the incontinence protection in place in the underpants during use. Various other types of glue patterns, for example transverse, are possible, as well as other types of fastening means such as hooks, loops, fasteners, special briefs or the like. A protection against incontinence of the type presented in figure 1 is mainly intended to be used by people suffering from a relatively mild incontinence and can be easily used in a user's underpants. The fastening means 6 serves to maintain the incontinence guard in place during use. The incontinence guard is in the form of an hourglass with wider end portions 7 and a narrower crotch portion 8 that lies between the end portions. The crotch portion 9 is the portion of the incontinence protection that must be worn in the crotch, between the legs of the user, and serves as a reception portion for the discharged body fluid. Figure 3 shows an absorbent figure in the form of a diaper which, like the incontinence protection described above, comprises a liquid-permeable upper sheet 2, a liquid-impermeable backing sheet 3 and an absorbent body 4 which is found between the two sheets and also an acquisition layer 5 applied between the upper sheet 2 and the absorbent body 4. In the illustrated embodiment, the upper sheet has a hole 16 opposite the intended wetting area where the acquisition layer 5 is located. exposed directly to the user in this area. Instead of a hole 16, several smaller holes can be provided. The diaper is meant to enclose the lower part of the user's trunk like a pair of absorbent pants. It has a front portion 7a whose purpose during use is to be employed against the front of the user's body, a rear portion 7b whose purpose is to be used against the back of the wearer, and a narrower crotch portion 8 between the front portion and the posterior portion, whose purpose is to be used in the crotch between the legs of the user. To fasten the diaper on the desired form of trousers, strips of tape 6 'are found around the wearer's waist. Other fastening devices such as for example hook and loop devices (sailboat), hooks, etc., are also possible. It will be appreciated that the incontinence and diaper protection illustrated in the drawings described above are only non-limiting examples of an absorbent arti Thus, artiform as the construction thereof may vary. The absorbent artican also be a diaper, a diaper pants, a sanitary napkin or the like. The absorbent artican be disposable or reusable. In the case of reusable arti, other materials than those described above are used as a liquid-permeable upper sheet and an absorbent body, respectively. Between the liquid-permeable top sheet 2 and the absorbent body 4 a porous and resilient acquisition layer 5 is arranged which has the ability to quickly receive large quantities of liquid and to distribute the liquid and temporarily store it before being absorbed by the body Underlying absorbent 4. This capacity must be essentially maintained also after wetting the material. The acquisition layer 5 can either cover the entire absorbent body 4, extend out of it, or cover only part of the central portions of the absorbent body. According to the invention, the acquisition layer 5 consists of a pair of continuous fibers 9, which are known as tow, which have been joined into points or lines forming a joining pattern 10, but otherwise are substantially joined together. they. In the embodiment illustrated in Figure 1, the binding pattern 10 is a pattern of lines with short lines placed in the zigzag type configuration. The bonding pattern is achieved, for example, by ultrasonic welding or by another type of thermal bonding. Examples of other suitable thermal bonding methods are calendering, laser bonding, etc. this implies that at least a part of the fibers in the tow are thermoplastic. Example of thermoplastic fibers are polyolefins, polylactides, polyamides, polyesters, and the like. Also included are those known as two-component fibers. As an alternative to thermal bonding, a printing joint can be made through a joining agent or a point connection either mechanically through what is known as entanglement by sewing or by water jets. The choice of the type of union is decided mainly based on the type of fibers used in the tow. The design of the bonding pattern 10 can obviously vary within wide limits. The pattern can be in the form of points or preferably line. The lines can be straight as well as curves and the length can vary from a few millimeters to extend transversely or diagonally throughout the entire arti Preferably the lines extend transversely or obliquely through the longitudinal direction of the fibers., in such a way that several fibers are joined to each other by each joining line. It is also advantageous if different bond lines are joined together as seen through the longitudinal direction of the fibers such that a major part of the fibers is joined at least some part of their length. The binding pattern can be the same throughout the acquisition layer 5 or it can be different in different parts of said acquisition layer, in such a way that the bonding pattern can be more scarce in the wetting area and denser outside of said wetting area. It is also possible to design the bonding pattern in such a way that the layer 5 has a different thickness in different parts of the article, for example that it is thinner in the central portions of the article and thicker in the adjacent edge portions in order to orating a bowl shape that provides a liquid reception volume, alternatively thicker in the central portions than in the adjacent edge portions in order to offer better contact with the body. The tow is supplied in bags or in the form of sacks or rolls of continuous fibers, either wavy or curled straight. The crimped or crimped fibers are preferred in this case since they offer a very open structure that allows the passage of air. The sacks or the like are opened in special conversion devices where the fibers are separated from each other, stretched and placed in a layer essentially of the same thickness. The layer is bonded to the desired bonding pattern according to the above and cut into suitable lengths either before or after application in an absorbent article. The joint can be processed alternatively after cutting. A tow is a relatively inexpensive way of supplying fibers in comparison with shielded cushions or the like which are commonly used as acquisition materials. In FIGS. 4 and 5, a piece of layer 11 of continuous fibers 9 which have been joined in a simple joining pattern 10 with short transverse lines is shown schematically. Except in the binding sites, the fibers 9 are not joined together. The fibers in the tow can be of any suitable material such as polyethylene, polypropylene, polyamide, polyester, polylactide, polyvinyl acetate, cellulose acetate, regenerated cellulose such as viscose or rayon, or of a two-component type with a shell of a polymer having a lower melting point and a core of a polymer having a higher melting point. In a two-component fiber, the core that is not melted offers rigidity and resilience while the shell provides bonding. Fibers of this type which have a high resilience are especially preferred, for example polyester, copolyester and polypropylene. The thickness of the fibers may vary but should be within the range of 0.5 to 50 dtex, preferably from 1.5 to 25, and preferably from 2 to 15 dtex, if the material is to be used as an acquisition layer. The ventilated open structure in combination with the relatively thick fiber dimension offers a very rapid acquisition of liquid. In addition, the material is strong due to the continuous fibers that offer strength in the longitudinal direction, and the bond pattern that provides resistance in the transverse direction. In the previous example, the material has been used as an acquisition layer 5 under a liquid-permeable top sheet 2. This is also illustrated in Figure 6. The base weight of the bonded fiber tow must be in this case of at least 10 g / m2, preferably within the range of 10 to 1000"g / m2, especially between 30 and 700 g / m2 and especially preferably 30 to 350 g / m2. any optional type but preferably has a relatively open structure that allows a rapid acquisition of liquid.The upper sheet 2 can be joined on the acquisition layer 5 at the junction points 10. In Figure 7 an alternative mode is shown where the bonded fiber tow according to the present invention is used as a liquid-permeable top sheet 12. The basis weight must in this case be at least 5 g / m2, preferably in the range of 5 to 500 g / m2, and more preferably between 5 to 200 g / m2 and the thickness of the fibers should be within the range of 0.5 to 50 dtex, preferably 1.5 to 25 dtex and especially from 2 to 15 dtex. In another aspect, the material may be the same as described above. Underneath the upper sheet 12 an acquisition layer 15 is placed which can be of an optional type. The absorbent article according to Figure 7 further comprises an absorbent body 14 and a backsheet -permeable to liquids 13. In the embodiment according to Figure 8, the fiber tow attached in accordance with the present invention has been employed as a top sheet and an acquisition material 22 in combination. The surface weight must in this case be at least 10 g / m2, preferably within the range of 10 to 1000 g / m2, more preferably from 30 to 700 g / m2 and especially from 30 to 350 g / m2 and the The thickness of the fiber should be within the range of 0.5 to 50 dtex, preferably 1.5 to 25 dtex and especially 2 to 15 dtex. The absorbent article according to figure 8 further comprises as usual an absorbent body 24 and a liquid-permeable backsheet 23. The embodiment according to figure 9 differs from the embodiment illustrated in figure 8 due to the fact that a support material 25, for example in the form of a non-woven structure, has been integrated into the lower side of the combined upper sheet / acquisition layer 22. Said support material can alternatively be integrated to the upper side of the upper sheet / layer of acquisition 22 either to the acquisition layer 5 in accordance with Figure 6 or to the top sheet 12 in accordance with Figure 7. In the embodiments according to Figures 7-9 the fiber tow attached in accordance with the present invention will be directly in contact with the skin of the user. In this case there is a strict requirement of softness and comfort of the material. Since the material consists of continuous fibers there are no sharp protruding ends of fiber that can irritate the skin, but the material is very soft and flexible. It also has sufficient strength and good wear resistance due to the longitudinal continuous fibers 9 which offer resistance in the longitudinal direction, and due to the bonding pattern that offers resistance in the transverse direction. In accordance with what is stated above, wavy or crimped fibers are preferred in the tow, since they offer an additional open and light structure. It is also possible to use a combination of straight and crimped or crimped fibers. It is also possible to use different fiber types or different thicknesses of fibers in different parts of the tow, that is, in different layers or zones thereof. In this way it is possible to create desired absorption patterns. It is also possible to create hydrophilicity gradients and / or different pore sizes. You can also mix superabsorbent fibers in the tow. TIME OF ACQUISITION "" "Comparative tests were carried out to measure the acquisition time of the absorbent articles for a product of a reference product" in the form of a commercially available light incontinence product and on the other hand in the form of a product of test wherein the top sheet and acquisition layer had been replaced by a tow attached in accordance with the present invention. The top sheet in the reference product was carded nonwoven with a basis weight of 23 g / m2 and the acquisition layer was a stitched cushion having a basis weight of 68 g / m2. The absorbent core was the same in both the reference product and the test product and consisted of two layers, a top layer of a mixture of CTPM (omechanical chemoter pulp) and superabsorbent and a lower layer in the form of a mixture. of chemical pulp and superabsorbent. The bonded fiber tow in the test product replaced the topsheet and the acquisition layer of the reference product consisted of polyester fibers of a thickness of 6.7 dtex and the basis weight was 70 g / m2.

As a test liquid, a synthetic urine was used according to the description, for example, in EP 0,565,606 and can be obtained from Jayco Pharmaceuticals Co., Pennsylvania. The composition was 2 g / l KCl; 2g / L Na2SO4; 0.85 g / L (NH4) H2P04; 0.15 g / l (NH4) H2P04; 0.19 g / l CaCl2 and 0.23 g / l MgCl2- The pH of the composition was 6.0 to 6.4. Three additions each of 50 ml of synthetic urine with an interval of 10 minutes were carried out. The time required for the absorption of all the liquid (visual observation) was measured. The result appears in the following table. Product Acquisition Time Acquisition Time Acquisition Time Ks) 2 (s) 3 (s) Reference 3.65 7.10 11.66 Test 3.35 5.29 _ 6.64 As can be seen from this test, the test product had a faster acquisition time That the reference product. The difference was especially significant in the second wetting and in the third wetting. In Figure 10 a simple device is shown schematically with which the excellent acquisition of an absorbent article in accordance with the present invention can easily be demonstrated. The device comprises a pedestal 25 in the form of a pair of legs placed at an acute angle between them. The article 1 is folded longitudinally in a manner corresponding to the manner in which it is bent when placed in the crotch portion between the user's legs, and is placed on the pedestal 25 in the bent condition. A test liquid in the amount of for example 50 ml is quickly emptied onto the article. A conventional absorbent article will probably leak and will not be able to absorb all the liquid quickly enough. An absorbent article in accordance with the present invention on the other hand will be able to absorb the liquid more quickly and the risk of leakage is considerably reduced.

Claims (14)

1. CLAIMS _ ^ An absorbent article such as diaper, diaper brief, incontinence protection, sanitary napkin, wound dressing or the like comprising a liquid-permeable top sheet (2; 12; 22), a waterproof backing sheet to liquids (3; 13; 23) and an absorbent body (4; 14; 24) placed between them, characterized in that the article comprises a layer of continuous fibers (9), known as tow, joined in points or lines in a binding pattern (10), but where the fibers of another form are not substantially joined together.
2. An absorbent article according to claim 1, characterized in that the bonding pattern (10) is not random.
3. An absorbent article according to claim 1 or according to claim 2, characterized in that the continuous fiber layer (9) is used as a liquid acquisition layer (5) applied between the upper sheet (2) and the body absorbent (3).
4. An absorbent article according to claim 3, characterized in that the layer of continuous fibers (9) has a basis weight of at least 10 g / m2, preferably in the range of 10 to 1000 g / m2, more preferably 30 to 700 g / m2, and especially from 30 to 350 g / m2.
5. An absorbent article according to claim 3 or according to claim 4, characterized in that the upper sheet (2) in the intended wetting area has at least one opening (16) through which the liquid acquisition layer (5) is exposed towards the user.
6. An absorbent article according to claim 1 or according to claim 2, characterized in that the continuous fiber layer (9) is used as a liquid-permeable top sheet (12).
7. An absorbent article according to claim 6, characterized in that the layer of continuous fibers (9) has a basis weight of at least 5 g / m2, preferably in the range of 5 to 500 g / m2, more preferably 5 to 200 g / m2.
8. An absorbent article according to claim 1 or claim 2, characterized in that the continuous fiber layer (9) is used as an integrated top sheet / liquid acquisition layer (22).
9. An absorbent article according to claim 8, characterized in that the layer of continuous fibers (9) has a basis weight of at least 10 g / m2, preferably within the range of 10 to 1000 g / m2, more preferably 30 to 700 g / m2 and especially from 30 to 350 g / m2.
10. 10. An absorbent article according to any of the preceding claims, characterized in that at least a portion of the continuous fibers (9) in said layer are crimped or crimped.
11. 11. An absorbent article according to any of the preceding claims, characterized in that the joining pattern (10) comprises points or lines crossing the longitudinal direction of the continuous fibers (9).
12. 12. An absorbent article according to claim 11, characterized in that different lines of junction are joined together as seen in the transverse direction of the article, in such a way that a main part of the fibers (9) are joined to along at least part of its length.
13. An absorbent article according to any of the preceding claims, characterized in that the continuous fiber layer (9) is supported by a support layer (25), for example a non-woven structure or a plastic film.
14. 14. An absorbent article according to any of the preceding claims, characterized in that the continuous fiber layer (9) comprises fibers of different material and / or different thickness.