MXPA99005688A - A dry laid structure comprising odour control means - Google Patents

Abstract

The present invention relates to a dry laid fibrous structure (40) for providing odour control. The structure comprises a dry laid fibrous web (22) and a latex coating (50) on at least one surface of the web and further comprises an odour control means (26) for controlling malodours. The structure can be an absorbent structure for further providing adsorption of fluids.

Description

STRUCTURE PLACED IN DRY COMPRISING ODOR CONTORL MEANS FIELD OF THE INVENTION The present invention relates to fibrous structures placed dry to provide odor control and, optionally, to absorb fluids. The structures contain means of controlling the odor and are united by the application of a liquid binder; these are particularly for use in disposable absorbent articles.

BACKGROUND OF THE INVENTION Fibrous structures, particularly fibrous structures for absorbing fluids are manufactured for many uses, for example, they are incorporated in absorbent articles such as disposable diapers, incontinence pads and catamenial towels for fluid absorption or fluid transmission and / or as diffusion elements, for example as absorbent cores that are intended to absorb and retain bodily fluids. The fibrous structures, and more specifically the fibrous structures used in absorbent articles as fluid absorbers or for the transmission of fluids and / or as diffusion elements normally comprise a multiplicity of components to improve their specific performances; additional components may also be included to provide the structure with additional benefits. Although the primary focus of absorbent articles remains on the ability of these items to absorb and retain fluids, another important development area in this field is the control of the odorous compounds contained within the absorbed fluids or their degradation products. . There is a wide variety of compounds that may be present within an absorbent article during use, which result in the formation of malodors. These compounds include fatty acids, ammonia, amines, sulfur-containing compounds and ketones and aldehydes. The literature shows many references relating the control of odor in products such as diapers, catamenial products or incontinence pads and various means of odor control comprising different odor control agents that are described for use in absorbent articles in order to to devote to the problem of the formation of bad odors. These agents are available in different forms, for example, as a water-insoluble particulate material, or as water-soluble compounds. Accordingly, the odor control means can be incorporated in absorbent articles in many ways, typically being comprised within the fibrous structure of the absorbent article, for example, at least partially within the absorbent core, for example by spraying a solution of a compound of control of the suitable water-soluble odor on the fibrous structure, or, alternatively, by distributing an odor control means in the form of particulate material within a fibrous structure. The interactions between the odor control means and the components constituting the absorbent article and, more specifically, constituting the fibrous structure comprising the odor control means, are therefore possible, and some of these interactions may decrease the effectiveness of the odor control means. Dry placement processes, more specifically air placement processes are widely used to produce dry fiber wefts, which can in turn be used, for example, as structures to absorb fluids.

Particularly, dry placement refers to the formation of carded frames, ie, frames in which the fibers are oriented (carded), in a given direction, while that the air placement process refers to the formation of frames with a completely random fiber orientation; The properties of these wefts placed with air are therefore a little isotropic. The fibrous webs produced by the dry placement process are softThey are flexible and porous and are particularly suitable for use as liquid absorbing structures in absorbent articles, such as disposable diapers, sanitary napkins, incontinence pads, and handkerchiefs. The manufacturing process of dry laying generally comprises the step of forming and placing the weft and the step of joining and stabilizing the weft; in the process of dry placement, in fact fibers that can be of any type, for example, cellulosic, synthetic or a combination thereof, are formed or condensed in one frame, but this frame lacks integrity and must therefore be stabilized Different techniques for joining and stabilizing a dry formed web are known in the art, that is, mechanical, thermal and chemical bonding processes. The union of a weft structure by means of a chemical is one of the most common methods of joining in the non-woven materials industry, and consists in the application of a chemical binder to the weft and in the curing of the binder. The very widely used chemical is latex, since it is cheap, versatile, easy to apply, and very effective as a binder. Various methods are known for applying the latex binder to the fibrous web, although spraying and stamping are particularly preferred for fibrous webs intended for use in absorbent articles. Methods for incorporating additional components into a dry fibrous web are also known in the art; particularly, in U.S. Patent No. 4,765,780 there is disclosed a process and apparatus for forming air-laid fibrous webs having a multiplicity of components such as a core Two layer absorbent with one layer having gelling absorbent material in the particulate form homogeneously mixed therein, and the other layer being substantially free of particles of gelling absorbent material. Similar techniques can be used to incorporate different component types within the dry-laid fibrous web, for example, an odor control means in the form of particles to provide the absorbent structure constituted by the dry-laid fibrous web The additional benefit of odor control. European Patent Application EP-A-463 716 describes a dry-laid absorbent structure comprising a fibrous web with a gelling absorbent material therein and which is stabilized by the application of a latex coating to at least surface of the plot. Although the coating imparts integrity to the resulting structures without affecting the effectiveness of the gelling absorbent material these structures are not suitable for providing odor control, which is a particularly important feature in structures that are intended for use in absorbent articles. The latex binder is normally in aqueous emulsion, and can be applied to one or both of the larger flat surfaces of the fibrous web, but the negative interaction between the latex composition and the odor control means can occur, particularly when the Odor control comprises one or more odor control agents in the form of particles, since the latex binder can generally create a coating on the odor control particles and therefore at least partially affect their effectiveness. The problems created by the interaction between a latex binder and an odor control medium, particularly in the form of particles, are somewhat different from those involved in the combined use of such a binder and an absorbent material of gelation within a unitary structure. Without being bound by any particular theory, the liquid absorption mechanism of the gelling absorbent material is based on swelling and acts through the internal diffusion of the liquid. Therefore, a particle of the gelling absorbent material partially coated by a latex binder can still acquire fluid from the uncoated portion and diffuse it internally, still being able to inflate at a reduced rate. Odor control agents on the other hand, particularly those in the form of particles, usually can not relate to this mechanism of internal diffusion and their performances are strictly related to the surface that is actually available for the interaction between e! agent and odorous substances. Even a partial coating by a latex composition, therefore, effectively reduces the odor control ability of the odor control agents in substantial terms. This effect may be particularly relevant when an absorption mechanism against odorous gaseous compounds is involved in the odor control action of some of the odor control agents as this is the case, for example, by activated carbon and zeolites . Consequently there is still a need for a dry-laid fibrous structure, preferably an absorbent fibrous structure placed in dry, stabilized by means of a latex binder and capable of providing odor control. It has now been discovered that this need can be treated by a dry-laid fibrous structure, stabilized by means of a latex binder and comprising odor control means, in which negative interaction between the odor control means is avoided. and the latex binder or at least reduce, therefore, by providing an absorbent structure that is soft and has good integrity, while also of importance to odor control.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates to a dry-laid fibrous structure for providing odor control, and optionally for absorbing fluids comprising a dry-laid fibrous web having a first surface and a surface aligned approximately opposite to the first surface; The fibrous structure comprises a latex coating on at least one of the surfaces and further comprises an odor control means for controlling odors.

BRIEF DESCRIPTION OF THE DRAWINGS Although the description concludes with the claims singling out and claiming differently from the present invention, it is believed that the present invention will be better understood from the following description in combination with the accompanying drawings: Figure 1 is a viewed in schematic fragmented iaterai elevation of an apparatus for making a fibrous structure according to the present invention; Figure 2 is an enlarged cross-sectional view of a fibrous structure according to the present invention; Figure 3 is an enlarged cross-sectional view of an alternate embodiment of a fibrous structure according to the invention; DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fibrous structure placed in dry to provide odor control; preferably, the dry laid fibrous structure of the present invention is also intended for the absorption of fluids and for controlling the odors associated with the absorbed fluids. The structure is constituted by a fibrous web placed dry by means of a liquid binder preferably a latex binder and comprises an odor control means. In a preferred embodiment, the structures of the present invention are incorporated as absorbent structures, into absorbent articles, preferably as absorbent cores and are intended to absorb and retain the various body fluids. Absorbent articles, more specifically disposable absorbent articles, refer to articles such as sanitary napkins, diapers, incontinence pads that are worn by a user adjacent to the body and are intended to absorb and contain the various body fluids that are discharged from the body (for example, vaginal discharge, menstruation, sweat, and / or urine), and which are intended to be discarded after a single use). Disposable absorbent articles comprise a liquid permeable topsheet, a fluid impermeable backsheet, which may optionally be permeable to water vapor and / or gas and an absorbent element comprised therebetween. The term "use", as used herein, refers to the period of time that begins when the absorbent article is actually placed in contact with the user's anatomy. The development of unpleasant odors from body fluids, (such as sweat, menstrual blood, vaginal discharges or urine), are basically due to two different causes, a) malodorous chemical compounds already contained in body fluids; and b) malodorous chemical compounds produced by bacterial metabolism when the bacterium comes in contact with body fluids for a period of extended time. Means for controlling the media associated with body fluids and their incorporation into disposable articles are widely known in the art, and various odor control agents are disclosed in the literature. Different classes of odor control agents are known in the art according to their different mechanisms of action. Disposable absorbent articles may comprise only an odor control agent, or combinations of various odor control agents, optionally belonging to different classes and therefore developing different actions for the control of unpleasant odors associated with body fluids. A first class of odor control agent is constituted by those compounds that interfere with bacterial metabolism, in order to avoid and reduce the production of malodorous metabolites of bodily fluids.; These agents can be bactericidal or bacteriostatic and are typically available as water-soluble compounds. A second class of odor control agents comprises those compounds, typically in the form of particles which are capable of absorbing within their structure the odoriferous substances, both those already present in bodily fluids as such, such as those produced by bacterial metabolism. Another class of odor control agents comprises perfumes that essentially hide unpleasant odors; encapsulated moisture-activated perfume particles can also be used, in which the perfumes are released only when the material is wetted, to provide their action during the use of the product, and to optionally prevent interaction with other odor absorbing agents, before the product is used, if this combination is normally used as the means of odor control. Any suitable odor control agent known in the art can be incorporated into the dry laid fibrous structures of the present invention to provide the structure with the benefit of odor control, for example, towards those odors associated with absorbed body fluids. when the dry-laid fibrous structure is also capable of absorbing fluids and is preferably incorporated in the disposable absorbent articles. Suitable odor control agents that can be employed in the practice of the present invention can be water soluble antibacterial compounds. These compounds include, for example, halogenated feline compounds (U.S. Patent No. 3,093,546), periodic acids (U.S. Patent No. 3,804,094), various copper compounds, especially copper acetate (U.S. United States No. 4,385,632), various quaternary ammonium salts, which are well known for their antibacterial properties, for example, cetyl pyridinium chloride, and the like. Alternatively, antibacterial compounds can be used in combination with various particulate materials which, in use, and in the presence of moisture, release the antibacterial agent, the zeolite materials, such as the zeolites which are bacterized by virtue of having absorbed therein and on the same various bacterial cations such as copper, silver and zinc, can be advantageously used in the practice of this invention (U.S. Patent No. 4,525,410). In a preferred mode, the odor control agent is a water-insoluble, particulate odor absorbing material, such as chlorophyll particles, activated carbon granules, charcoal, ion exchange resin (Japanese Patent No. 87019865) , activated alumina and zeolite absorbing materials, including the well known "molecular sieve" zeolites, type A and X, and the zeolite materials marketed under the trade name ABSCENTS by Union Carbide Corporation and UOP and which are typically available as a white powder in the 3 to 5 micron particle size scale. In a known way the odor control agent can be a water-insoluble particulate absorbent material such as chlorophyll particles, activated carbon granules, charcoal, ion exchange resin (Japanese Patent No. 87019865), activated alumina and zeolite absorbing materials, including the well known molecular sieve zeolites of type A and X and the zeolite materials marketed under the trade name ABSCENTS by Union Carbide Corporation and which are typically available as a white powder in the scale of particle size from 3 to 5 microns. The odor control agents used in the present invention may also comprise other compounds such as cyclodextrin, chelating agents, parabens, chitin, pH regulated materials, silica gel, clays, diatomaceous earth, polystyrene derivatives, starches and the like. For example, chelating agents such as those described in the European patent applications EP 96109178.2 and EP 96109179. 0, both applications filed on June 7, 1999, are 'particularly preferred. Some of the partially neutralized hydrogel-forming gel-forming absorbent materials, such as the polyacrylate gelling material and the acrylate-grafted starch gelling material can also be used, preferably in combination with other odor control agents. In addition, odor control agents may comprise acidic compounds such as ascorbic acid, stearic acid, boric acid, maleic acid polymers, malonic acid, maleic acid, polyacrylic acid and monopostasium phosphate, or basic compounds such as inorganic salts of carbonates. , bicarbonates, phosphates, bisphosphates, sulphates, bisulphates, borates, and mixtures thereof, such as those described in the patent of the United States No. 5037412, or as the combination of boric acid and sodium tetraborate described in international application WO 94/25077. It should be understood that the odor control means employed in the practice of the present invention is not simply the odor control agent per se added to the fibrous structure. In contrast, the odor control means comprises any combination of odor control agents and, optionally, other materials such as binders. Agglomerates of different odor control agents, for example, with a binder, can therefore also be used, such as, for example, an agglomerate of zeolite and silica in the form of a particle, as described in the European patent application. No, 96109175.8, filed June 7, 1996. The odor control agent, on the other hand, is the specific odor control compound. Preferably, the odor control agents are used in the present invention in the form of particles and comprise those agents that act as adsorbers to the odorous gaseous compounds. Particularly preferred are the odor control means comprising zeolite, silica, preferably in the form of silica gel, gelling absorbent materials and combinations thereof as the odor control means described in the international application WO 95/26207 , and in the European applications Nos EP 96109177.4, EP 96109173.3, EP 96109174.1, EP 96109176.6. The fibrous structures of the present invention can be made using conventional equip designed for dry place processes and although the invention is described here below, with particular reference to structures placed with air, it should be understood that other processes of application are also applicable. dry place, for example, carding. The invention will be described as a fibrous structure placed with air, which is capable of providing the absorption of aqueous fluids, particularly fluids bodily, and control the odors associated with the absorbed fluids, being intended to be incorporated as the absorbent structure in a disposable absorbent article, for example, a sanitary napkin. Figure 1 is a simplified schematic illustration of a preferred embodi for the manufacture of the fibrous structure of the present invention. According to this embodi, the air forming system, indicated generally by the number 10, includes a distributor unit 12, arranged transversely above a continuous forming screen 14 mounted on the rollers 16 and driven by a suitable motor (not shown) , and a vacuum means or suction box 18, which is placed below! sieve. In a conventional air-forming system, the upstream of the distributor unit is a defibrator or feeder "not shown", such as a hammer mill or a Rando feeder, where the bales, coatings or the like are defibrated and the fibers can also be to be cleaned and / or mixed if necessary or if desired depending largely on the type of fibers used, the mixture of fibers used and the final pressed product, for example, the fibers of wood pulp can be mixed with synthetic fibers and they are applied as a mixture by a simple distributor, or different fibers that can each be transported by a different distributor to the screen to form separate sheets or layers The porous forming screen 14 is essentially coextensive with the distributors, and the suction box 18 under the sieve pulls the air stream downwards and transports the fibers towards the surface of the sieve forming the layers or a tram loose 22. At this stage of the process, the weft exhibits little integrity, and the vacuum means retain the loose, fibrous web on the screen. The web 22 has a first surface 6 facing the distributor and a second surface 8, opposite the surface 6, which faces towards the forming screen 14.

It should be understood that the system can be modified to control the composition and thickness of the final product. For example, the dispensing unit may comprise a plurality of individual distributors and although Figure 1 schematically shows two distributors at 12A and 12B, this number of distributors and the particular distribution may be altered or varied depending on such factors as the speed of the machine. , the capacity, type of fibers and final product desired. The screen 22 formed on the screen 14 has incorporated therein an odor control means constituted by one or more odor control agents in the form of particles or powder. In a preferred embodiment as shown in Figure 1, a metering unit or feed hopper 24, which contains the particles 26 of the odor control medium, or, more briefly, the odor control particles 26, is placed in the middle part of the distributor unit, that is, between the distributors 12A and 12B. In this way, the odor control particles 26 are deposited between the layers of fibers placed by each distributor. That is, the odor control particles 26 are discharged from the hopper 24 onto the moving fiber layer placed by the distributor 12A, and the fiber layer placed by the distributor 12 is placed on the odor control particles 26. However, it should be understood that the layers are relatively porous, and therefore, the odor control particles 26 may tend to migrate a little towards the adjacent layers. Where desired, the odor control particles can be mixed with the fibers in one or more distributors, such as in the distributor 12A or 12B thereby forming a web with the odor control particles and internally mixed with one or more of the fibrous layers of the weft. However, it is preferred that the odor control particles are distributed within the thickness of the web 22, intermediate the first and second surfaces 6,8. In this stage of the process, the frame 22 condensed on the screen of Training 14 has very little integrity and requires stabilization. The web is advanced by the continuous screen, and if desired, the web can be first passed between compression rollers (not shown), which can be heated, to densify the web, but this step is optional. This densification step increases the penetration of the latex into the web, and the degree or percentage of densification may vary depending on factors such as the amount of odor control particles, the basis weight of the web, the desired degree of penetration of the latex. in the plot, and the final product sought. From here, the weft is transported to a suitable dispensing means 30, ta! as a spray nozzle, a blade, a roller applicator or the like, wherein a latex binder is applied to the first surface 6 of the loose weft 22. A vacuum is applied by the same aspirator of the screen 18 placed under the medium Dispenser and sieve helps pull the latex into the weft. The dispensing and applicator means is essentially coextensive with the width of the weft and preferably a substantially uniform coating is applied to the weft surface. However, the latex can be applied as a non-uniform, random or patterned coating, and because the latex is water-based, it will diffuse throughout the weft and will function as a binder when it is covered. The latex when cured imparts integrity to the weft and therefore, some penetration of the latex is required. The limit or degree of penetration of the latex in the weft is controlled by controlling the amount of the latex applied and by controlling the vacuum applied to the weft in which the vacuum helps to aspirate the latex into the weft. Latex is normally applied as an aqueous emulsion and is a thermal hardening plastic. In order to activate the latex, the latex emulsion contains a suitable curing agent or crosslinking agents, and after the web is coated, the latex is cured to effect crosslinking. Very typically the curing is achieved by passing the coated web through a hot air oven or through an air dryer 32, and the temperature typically varies from about 100 ° C to 200 ° C, but this depends on the type of specific latex resin used, the curing agent or the crosslinking agent, the amount of latex, the thickness of the weave, the degree of vacuum and the speed of the machine. It is desirable to coat the second surface 8 of the weft 22 with the latex as well, and this is easily accomplished by the dispensing means 36 as the weft 22 is conveyed onto the second screen 34 which operates around the pulleys 191, 192, 93, and 194. Second dispensing means 36 includes a screen aspirator 37. This second latex coating is itself cured by passing the screen through a second oven 38 within approximately the same temperature range. The resulting absorbent fibrous structure 40 leaving the last oven now exhibits sufficient integrity and can be cut, rolled, packed, etc. The absorbent structure 40 made in accordance with the above process is illustrated in Figure 2. The absorbent structure indicated generally by the numeral 44, comprises a weft 22 of randomly distributed fibers 46, such as fibers of wood pulp and particle control odor 26 that are distributed in the web 22. It will be noted that the odor control particles are more concentrated in the middle zone of the web 22 that is intermediate to the first and second surfaces 6 and 8, but some particles migrate to others sections of the web 22. Both of the first and second surfaces 6 and 8 of the web 22 carry a latex coating 50, indicated in the drawings by a shading, which has penetrated or impregnated the web 22 to some extent already partially coated some of the fibers and the odor control particles. As explained above, the penetration is controlled so as not to substantially affect the odor control ability of the odor control particles. Despite the latex coating, the fibrous structure is still soft yet resistant and absorbent, exhibiting a relatively high tensile strength. It is desirable for the preferred absorbent fibrous structures of this type to have relatively low volume, because a denser absorbent structure, when compared to similar structures that do not contain latex and of approximately equal but higher volume absorption capacity, can be thinner still highly absorbent, and consequently less bulky. A reduction in volume is employed, which means a reduction in the volume of the absorbent structure without sacrificing significantly other desired properties which is important from the point of view of storage and packaging manufacture. Accordingly, for the products of the invention, the basis weight varies from about 50 g / m2 to 600 g / rr, preferably from about 75 g / m2 to 400 g / nf and most preferably about 250 g / rrl to 3d50 g / m2 There may be manufacturing restrictions when producing fibrous structures having a basis weight of less than about 50 g / m2 in which this fibrous structure may lack the desired strength.When the basis weight exceeds the upper limit, the The product may be too stiff and therefore not useful for most applications, any of a variety of fibers, including a mixture or combination, may be used in the fibrous structure of the present invention.The fibers may be cellulosic, cellulosic modified, or synthetic, and include fibers such as wood pulp, rayon, cotton, cellulose acetate, polyester, polyethylene, polypropylene, nylon and the like A fibrous structure comprising fibers cellulosics such as wood pulp fibers is particularly useful as an absorbent structure in products such as sanitary napkins, disposable diapers or cleaning tissues, because cellulose is liquid absorbent and therefore increases the overall absorbency of the structure. Products of this type, that is, fibrous structures that are also absorbent, also use advantageously a mixture of cellulosic and synthetic fibers, typically comprising from about 65% to 95% by weight of cellulosic fibers and more preferably up to about 20% by weight of the synthetic fibers. Synthetic fibers, which can be provided in any length including short length, can improve the strength of the structure. These can also be treated to make them hydrophilic, so as not to diminish the absorbent capacity of the preferred absorbent fibrous structure. The preferred fibrous structures described thus far comprise hydrophilic fibers and are also substantially absorbent to aqueous fluids being useful as absorbent structures in disposable absorbent articles. The dry-laid fibrous structures according to the present invention can also comprise hydrophobic fibers, only, for example, synthetic fibers which are therefore able to control the odor without absorbing and retaining the liquid. This type of structures can be comprised in the disposable absorbent articles as a liquid receiving and transmitting layer, for example, as an acquisition layer comprised between the upper sheet and the absorbent core, which is able to rapidly acquire the body fluid and of transmitting it to the absorbent core, performing at the same time its control action of the odor, the fluid. A structure that comprises hydrophobic fibers only and that is capable of acquiring and transmitting the fluid without substantially retaining it, can be advantageous in circumstances where the retention of the purchased liquid can clog the odor control means affecting its effectiveness. A structure according to the present invention comprising only hydrophobic synthetic fibers may also be useful in different applications, for example, as a filter medium. In this way, the type of fibers and the particular mixture can be varied depending on the final product. In addition, of the above uses, the absorbent structures of this invention can be suitably used for cushions for the incontinence, diaper cores, diaper inserts, and surgical and wound bands, which provide odor control, and preferably absorbent capacity. The odor control means included within the fibrous structure of the present invention may comprise a wide variety of odor control agents, in order to control unpleasant odors associated with fluids that may be in contact. In their preferred use, as absorbent cores in disposable absorbent articles, the fibrous structures of the present invention are intended to absorb body fluids. The various body fluids contain malodorous chemical compounds that include acyclic and cyclic amines, aldehydes, fatty acids, and compounds that contain sulfur such as sulfides. For example, the vaginal discharges and sanitary napkins used may contain many malodorous chemical compounds, for example, trimethylamine, pyridine, furaldehyde, isovaleric acid, and methyl mercaptan. Particular malodorous compounds that will be absorbed by various absorbent articles will vary depending on the person who is using the absorbent article and the type of absorbed body fluid, i.e., urine, menstrual fluid, vaginal discharge, perspiration, milk, etc. For feminine pads such as sanitary toaiias or pantiprotectors, how long the article is used, the amount of fluid that is absorbed and the exposure of the pad to different body fluids, will determine what odors can be emitted by the body. absorbent article. Any known odor control agent or any combination thereof that may be suitably included in a disposable absorbent article, including other materials such as binders and / or substrates, may be comprised within the fibrous structure of the present invention as the means of odor control Preferably, the odor control medium is incorporated into the fibrous structures of the present invention in the form of particles or powder, but this too can be incorporated by different known means, for example, by spraying an aqueous solution on the first fibrous layer placed by the distributor 12A in the apparatus illustrated in Figure 1. A preferred odor control medium can be a combination of silica gel, zeolite and particles of gelling absorbent material. The weight ratio of the gelling absorbent material to silica to zeolite is preferably in the scale from 1: 5: 1 to 1: 1: 5, preferably from 1: 3: 1 to 1: 1: 3, most preferably 1: 1. : 1 to 1: 1.5: 1.5. It has been found that the odor control material can be incorporated into the fibrous webs according to the present invention in an amount ranging from 2G g / m2 to 400 g / m2, preferably from 100 g / rr2 to 30 g / m2 , more preferably from 150 g / m to 250 g / m 2, with reference to the total surface area of the fibrous structure. Preferably, the fibrous structures of the present invention comprise from 20% to 80% by weight of the odor control medium. The weight of the odor control medium that can be actually used in various fibrous structures intended for different uses can be easily determined by skilled persons taking into consideration the size and type of fibrous structure and its intended use. The latex is applied as an aqueous emulsion or aqueous dispersion which typically contains from about 45% to 65% solids and these materials are readily available from various manufacturers. Because the latex emulsions are miscible in water, they can also be diluted, if desired, before being applied to the weft. Also these latex compositions are thermally hardened and in order to effect crosslinking they contain a small amount of a suitable crosslinking agent which are well known chemical agents for this purpose such as N-methylacrylamide. Any type of latex known in the art that is suitable for the fibrous structures of the present invention can be used with the condition that it does not generate detectable odors, especially after curing, as this may at least partially deplete the odor control capability of the fibrous structure before its intended use. The available latexes are classified by chemical family and those particularly include copolymers of vinyl acetate and acrylic ester, copolymers of ethylene vinyl acetate, copolymers of butaidene carboxylate, and polyacryl nitriles, and sold for example under the trade names of Airbond, Ariflex and Vinac from Air Products, Ine, Hycar and Geon from Groodrich Chemical Co., and Fulatex from HB Fuller Company. The amount of latex used in the absorbent structure can not be so high as to substantially affect or hide the effective odor control capability of the odor control means, and also the absorbent properties of the hydrophilic fibers or to impart a stiffness to the odor control. the structure to do it in practice. It has been found that the latex can vary from about 5% to 30% by weight of the structure, and preferably from about 10% to 20% by weight. The fibrous structures made in accordance with the present invention exhibit good integrity due to the coating of the latex, and still have a remarkable capacity of odor control, combined in a preferred embodiment with a good absorptive capacity of aqueous fluids, since the particles of odor control are affected by the latex latex binder only to a minimum limit, recognizing the control exercised over the application of the latex coating to the weft in order to form the fibrous structure of the present invention. The penetration depth of the latex binder in the fibrous web is controlled by the vacuum applied by means of the screen aspirators placed in correspondence with the dispensing means and by the selection of the amount that is applied to the web. In an alternate embodiment of the fibrous structure of the present invention which is also capable of absorbing aqueous fluids, a porous sheet of reinforcement such as a creped paper, a tissue or a non-woven material, in the fibrous structure either as a surface sheet or as an intermediate sheet disposed intermediate the first and second surface of the fibrous web. Referring to Figure 3, the absorbent fibrous structure 59 comprises fibers 60 and particles 61 of an odor control medium dispersed internally in the web 22, but more concentrated in half the thickness of the structure. The sheet 62 is present on a surface of the weft 22, while the opposite surface has a cured latex coating 64. The absorbent fibrous structure illustrated in Figure 3 can be formed on an apparatus similar to that illustrated in Figure 1, with some modifications that can be determined by an expert. In one embodiment, the sheet 62 can be a polyester or a nonwoven polyolefin material on which the fibers can be placed in the layer by means of the fiber distributor, a bond between the fibers and the sheet which is achieved by means of mechanical entanglement , while the latex binder is subsequently applied only to the surface of the weft opposite the sheet 62.

Claims (9)

1. A dry-laid fibrous structure to provide odor control, said structure comprising a fibrous, dry-laid web having a first surface and a second surface aligned approximately opposite to the first surface, and further comprising a latex overlying the less one of said surfaces of the fibrous web, the dry-laid fibrous structure being characterized in that it further comprises the odor control means for controlling odors.

2. A dry-laid fibrous structure according to claim 1, characterized in that the odor control means comprises one or more odor control agents.

3. A dry-laid fibrous structure according to any preceding claim, characterized in that the odor control means are in the form of particles or powder.

4. A dry-laid fibrous structure according to any preceding claim, characterized in that the odor control means is distributed within the thickness of the fibrous web placed in dry, intermediate to the first and second surfaces.

5. A dry-laid fibrous structure according to any preceding claim, characterized in that the dry-laid fibrous structure comprises from about 5% to 30% by weight of the latex, preferably from 10% to 20%.

6. A fibrous structure placed in dry according to any preceding claim, characterized in that the fibrous structure placed in dry comprises from 10% to 80% by weight of the odor control medium.

7. A fibrous structure placed in dry according to any preceding claim, characterized in that the fibrous structure placed in dry, is preferably placed with air.

8. A dry-laid fibrous structure according to any preceding claim, characterized in that the dry-laid fibrous structure is an absorbent structure to provide more fluid absorption, particularly aqueous body fluids.

9. A sanitary article comprising a dry-laid fibrous structure according to any preceding claim, preferably as the absorbent core.