MXPA97009298A

MXPA97009298A - Microporose fabric containing a microb adsorbent

Info

Publication number: MXPA97009298A
Application number: MXPA/A/1997/009298A
Authority: MX
Inventors: Ann Blaney Carol; Francis Cartwright William
Original assignee: Kimberlyclark Corporation
Priority date: 1995-06-06
Filing date: 1997-12-01
Publication date: 1998-02-01

Abstract

A cloth is described which includes a microbial adsorbent and which is capable of providing a microbial barrier which is still capable of allowing the passage of water vapor. The fabric is formed of a plurality of fibers which define at least one microporous conduit which allows communication, through the fabric, between their respective first and second surfaces. In particular, a portion of the microporous conduit is defined by the microbial adsorbent so that microbes attempting to pass through the fabric through the conduit must pass in close proximity to the microbial adsorbent. This arrangement allows the microbial adsorbent to veto the microbe by adsorbing it. The passage of the microbe through the fabric is prohibited. Laminates of the fabric with other materials are also described

Description

MICROPOROSE FABRIC CONTAINING A MICROBIAL ADSORBENT FIELD OF THE INVENTION The field of the present invention refers to fabrics which have antimicrobial characteristics.

BACKGROUND OF THE INVENTION Films have traditionally been used to provide barrier properties in single-use articles including, but not limited to, articles of general clothing, protective clothing, health-related products, including surgical drapes, sterile scrubs and wraps. and absorbent personal care products such as diapers, training pants, incontinence garments, sanitary napkins, bandages, and the like. In absorbent personal care products such as infant diapers and incontinence products for adults, films are used as outer covers for the purpose of preventing body waste from contaminating clothes, bedding and clothing. other aspects of the user's surrounding environment. In the area of protective clothing including hospital gowns and other operating room garments, the films are used to prevent the exchange of microorganisms between the user and the patient. These films are usually one to two mils in thickness and have a basis weight of approximately 0.7 to 1.5 ounces per square yard. Polyolefin films are most commonly used in such areas.

One of the significant disadvantages in the use of films, barrier materials, in most cases, if not all types of these products is that the films do not perform well their work. This is these form a complete barrier. Complete barriers of this type create a new problem completely in the sense that they block the exit of water vapor from the person or the article which it envelops. Therefore, these garments formed of such materials tend to become quickly very uncomfortable due to the accumulation of water vapor which is issued by the individual but is not allowed to pass through the film. The water vapor remains between the individual and the garment or article made of the material. The individual quickly develops a feeling of being "sweaty" or "sticky" as the relative humidity accumulates in the confined area and steam condenses there.

In response to this problem, those skilled in the art have tried to manufacture protective garments and other articles where the passage of microbes is undesirable from the materials that allow the passage of water vapor. Such materials include, for example, non-woven fabrics and laminates thereof as described in detail in United States Patent No. 4,041,203 issued to Brock et al. This patent is incorporated herein by reference in its entirety.

The microporous varieties of the films, either by themselves or incorporated into laminates, have been used in such products in an attempt to provide articles with more garment-type attributes, such as the ability to reduce relative humidity under the garment. , thus maintaining a higher degree of comfort for the user.

However, the use of non-woven fabrics and / or microporous films in certain non-protective clothing has not ceased to be difficult. For example, the use of such materials has raised concerns about their ability to prevent the transfer of microorganisms due to the size of microorganisms such as viruses and bacteria that are typically smaller than the pores of microporous films. The non-woven fabric materials, typically, are also characterized by conduits therethrough as long as they can retard the progress of the microbes, they do not guarantee complete barrier properties with respect thereto. For these reasons, none of these arrangements has proven to be completely satisfactory in view of the fact that these do not form a complete barrier for microbes.

Therefore, there is a need highlighted for a material that allows the passage of water vapor through it while effectively forming a barrier to the passage of small pathogens such as viruses, bacteria, cysts and nematodes. If such a material were a fabric such as a woven, blown melted or spunbonded fabric, it would be used alone or as a layer of a laminate to provide a general material which could have barrier properties against effective microbes , breathability (that is, allowing the passage of an adequate amount of water vapor) and a sense of touch.

OBJECTS OF THE INVENTION Therefore, it is an object of the present invention to provide a fabric which allows the passage of water vapor while still being an effective barrier material for microbes such as viruses, bacteria, cysts and nematodes.

It is a further object of the present invention to provide a fabric which allows the passage of water vapor, is an effective barrier for microbes such as viruses, bacteria, cysts and nematodes and, when exposed to a generally aqueous liquid, forms a physical barrier to the passage of such liquid through it in the area limited to such exposure.

It is another object of the present invention to provide a laminate of such a fabric with one or more other materials.

These and other objects and the wide scope of the applicability of the present invention will be apparent to those with ordinary skill in the art of the details given herein. However, it should be understood that the detailed description of the presently preferred embodiments of the present invention is given by way of illustration only because various changes and modifications very well within the spirit and scope of the present invention may be evident those with a skill ordinary in art with a view to the following description.

SYNTHESIS OF THE INVENTION In response to the aforementioned difficulties encountered by those with ordinary skill in the art, we have invented a fabric that has the first and second surfaces and which includes a microbial adsorbent and which is capable of providing a barrier to microbes while It is still able to allow the passage of water vapor .. The fabric can be woven or non-woven. For example, if the fabric is a non-woven fabric, this can be a spin-knitted fabric or a melt-blown fabric. The fabric is formed of a plurality of fibers. The fibers will be woven or, if the fabric is a nonwoven, interlaced in such a way that the ducts through the fabric defined by the fibers form micropores. Therefore, the fabric of the present invention will have in a broader aspect, a plurality of fibers which define at least one microporous conduit that allows communication, through the fabric, between the first and second surfaces. Such communication, in some modalities allows the passage of water vapor through the fabric. In particular, a part of the microporous conduit is defined by a microbial adsorbent so that microbes that attempt to pass through the fabric through a conduit must pass in close proximity to the microbial adsorbent. This arrangement allows the microbial adsorbent to veto the microbe by adsorbing it and forbidding its passage through the fabric.

In some embodiments the fabric can be formed of a thermoplastic polymer. For example, the thermoplastic polymer can be selected from the group including polyolefins, polyamides, polyesters and copolymers and blends in any combination of these and / or other suitable materials. For example, a polyolefin can be selected from the group consisting of polypropylenes, polyethylenes, polybutylenes and copolymers and mixtures thereof. The polyethylene can be a linear low density polyethylene.

By specifically making the type of microbial adsorbent present in the fabric, said fabric can be adapted to adsorb viruses, bacteria, cysts or nematodes or any or all of these. Naturally the fabric can be adapted to adsorb specific types of viruses, bacteria, cysts, nematodes, etc., depending on the use to which it is to be assigned.

In certain embodiments, the fabric may be designed to not only act as a filter for the microbes as a result of the presence of the microbial adsorbent but also be designed to act as a physical (mechanical) barrier to the liquids attempting to pass through the microbes. the same. For this purpose, the microbial adsorbent used may be one, which in the presence of a generally aqueous liquid, increases its volume by at least 1.5 times in no more than 120 seconds. For example, the microbial adsorbent may be one which, in the presence of a generally aqueous liquid, increases in volume by at least 1.5 times in no more than 60 seconds. More particularly, the microbial adsorbent may be one which, in the presence of a generally aqueous liquid, increases in volume by at least 1.5 times in no more than 15 seconds. Even more particularly, the microbial adsorbent can be one which, in the presence of a generally aqueous liquid, increases its volume by at least 2 times in no more than 1 second. In the event that such a microbial adsorbent is used, the adsorbent, when brought into contact with the generally aqueous liquid, will increase in size and swell. The swelling serves to block the microporous conduit whereby the microbial adsorbent is in close proximity. The blocking of the ducts creates a physical barrier within the microporous duct with the consequence that no additional liquid will pass.

An alternative way by which physical blockage can be obtained if the microbial adsorbent which is desired is to be used does not have the capacity of swelling (increase in size) is that the fabric may also include a charge of another particulate material which, in itself, swells in the presence of a generally aqueous liquid. In such embodiments, the particulates of the inflatable material and the microbial adsorbent may be incorporated within the fabric in an agglomerated form so that each individual agglomerate contains some of the non-swellable microbial adsorbent and some of the swellable material. Of course, the particles of the microbial adsorbent and the inflatable material must be located along the microporous passages which pass through the fabric. Otherwise, the particles may not perform their intended function.

In any case of these modalities the inflatable material is one which can increase its volume at least 1.5 times in no more than 120 seconds in the presence of a generally aqueous liquid. For example, the inflatable material may be one which, in the presence of a generally aqueous liquid, increases in volume by at least 1.5 times in no more than 60 seconds. More particularly, the inflatable material can be one which, in the presence of a generally aqueous liquid, boosts its volume by at least 1.5 times in no more than 15 seconds. Even more particularly, the inflatable material can be one which, in the presence of a generally aqueous liquid, increases its volume by at least 2 times in no more than 1 second.

The microbial adsorbent can be any of such adsorbent which is compatible with the fabric material being used. In some embodiments, the microbial adsorbent can be derivatized silane such as, for example, 3- (trimethoxysilyl) propyldimethyloctadecyl ammonium chloride [CH3) 3 Si (CH2) 3N * (CH3) 2C18H37C1]. This material was previously available from Dow Corning under the trade designation Dow Corning 5700. It is now available from Aegis Environmental. In other embodiments, the microbial adsorbent is a heavy metal. For example, heavy metal can be a silver.

In other embodiments, the microbial adsorbent may be a metal salt. For example, the metal salt can be a polyvalent metal salt insoluble in water. The water-insoluble polyvalent metal salt can be a salt of a metal selected from the group of metals including the Group IB, Group IIA, Group IIIB, Group IIIA, Group IVB, Group VIB. More particularly, the metal can be selected from the group including iron, aluminum, lead, magnesium, silver, calcium and alloys of one or more of iron, aluminum, lead, magnesium, silver and calcium. The salt can be selected from the group including hydroxides, phosphates, chromates, oxides and peroxides. For example, the salt can be selected from the group including one or more of ferric hydroxides, ferrous hydroxides, aluminum hydroxides, magnesium hydroxide, magnesium oxide, magnesium peroxide, lead chromate and calcium hydroxide.

In some embodiments, the microbial adsorbent can be selected from the group that includes colloidal clays. For example, colloidal clay can be a bentonite such as sodium bentonite and / or calcium bentonite. Colloidal clay can, in some embodiments, be hectorite.

The microbial filter fabric of the present invention can advantageously be formed into a wide variety of articles where it is desired to have a material which allows the passage of, for example, water vapor but which prohibits the passage of microbes through the same. For example, the article may be a garment, such as a surgical gown, foot protectors, face masks, head or hair coverings, aprons, jackets, pants, gloves, covers and generally speaking, clothing for the operating room.

Alternatively, it can be incorporated into a product such as, for example, a sterile wrapping material which is used to keep the sterile field around the doctor's instruments until they are used in the operation.

Similarly, the fabric of the present invention can be conveniently formed in a surgical drape for use on a patient during an operation.

DEFINITIONS As used herein the term "respirable" refers to any material which has a water vapor transmission rate (VTR) of at least 300 grams per square meter per 24 hours when measured in accordance with the standard ASTM E 96-80.

As used herein, the term "microbial adsorbent" refers to any material which has the ability to retain and / or inactivate microbes such as, for example, viruses, bacteria, cysts and / or nematodes on or near its surface.

As used herein, "microporous conduit" refers to any conduit which at some point along its length has a diameter of fifty (50) microns or less.

As used herein, the term "microporous fabric" refers to a fabric having a plurality of microporous passages therethrough to make the fabric breathable. The microporous fabric will have a hydro head of at least 25 centimeters of water when its hydro head is measured in accordance with method 5514 - of Standard Standard of Federal Test Methods No. 191A. For example, the microporous fabric can have a hydro head of at least 50 centimeters of water when measured as such.

As used herein, the term "generally aqueous liquid" refers to any liquid which has water as its main component. All body fluids including, without limitation, blood, saliva, menstrual fluids, mucosa, lymph fluid and urine, are expressly included within this definition.

Whether a material is "inflatable" is determined by first providing 100 mL of water contained in a 100 mL capacity glass stopper cylinder. After a first part of two (2) grams of the material were poured on the surface of the water and allowed to settle completely. Then, a second part of two grams of the material being tested was placed on the surface. After two (2) hours, the volume occupied by the material at the bottom of the cylinder was observed. For a material to be "inflatable" the material at the bottom of the cylinder must have an apparent volume of not less than 6 mL.

As used herein, the term "fabric" is intended to encompass any sheet type material which is formed in whole or in part, of a plurality of fibers. A fabric can be a woven or non-woven fabric. Typical examples of non-woven fabrics are fabrics formed by meltblowing and fabrics joined by spinning.

As used herein, the term "non-woven fabric" refers to a fabric having a structure of individual fibers or filaments which are interleaved, but not in an identifiable repetitive manner.

As used herein, the term "spunbonded or spunbonded fibers" refers to fibers which are formed by extruding melted thermoplastic material as filaments from a plurality of usually circular and thin capillaries of a spinner with the diameter of the extruded filaments then being rapidly reduced as indicated, for example, in U.S. Patent No. 4,340,563 issued to Appel et al., in U.S. Patent No. 3,692,618 issued to Dorschner and others, in the patent of the United States of North America No. 3,802,817 granted to Matsuki and others, in the patents of the United States of North America Nos. 3,338,992 and 3,341,394 granted to Kinney, in the patents of the United States of North America Nos. 3,502,763 and 3,909,009 granted to Levy, and in the United States of America Patent No. 3,542,615 granted to Dobo and others which is incorporated Click here for reference.

As used herein, the term "meltblown fibers" means fibers formed by extruding a melted thermoplastic material through a plurality of usually circular and thin capillary vessels such as melted threads or filaments into a gas stream ( for example, air) usually heated and at high speed which attenuates the filaments of the melted thermoplastic material to reduce its diameter. Then, the melt-blown fibers are carried by the high-velocity gas stream and are deposited on a collector surface to form a meltblown web of fibers randomly discharged. The meltblown is described, for example, in the United States patent of North America No. 3,849,241 granted to Buntin, in the patent of the United States of North America No. 4,307,143 granted to Meitner et al., And in the United States patent of North America No. 4,707,398 granted to Isneski and others all of which are incorporated herein by reference.

DESCRIPTION OF THE DRAWINGS Figure 1 is a widely amplified and schematic cross-sectional view of a breathable microbial barrier fabric designed in accordance with the teachings of the present invention.

Figure 2 is a highly amplified and schematic cross-sectional view of one embodiment of a breathable microbial barrier fabric designed in accordance with the teachings of the present invention and wherein the fabric also forms a physical barrier to the passage of liquids in the contact site of the fabric for such liquid.

Figure 3 is a schematic representation of a process for forming a microbial barrier fabric according to the teachings of the present invention.

DETAILED DESCRIPTION OF THE INVENTION Turning now to the drawings in which like reference numbers represent equal or equivalent structures or equal or equivalent process steps, an improved microporous fabric 10 of the present invention is shown. Typically, the fabric 10 will be formed of a non-woven fabric 12 of a thermoplastic material. Of course, the fabric 10 can be formed, in other embodiments of a wide variety of woven materials. The non-woven fabric 12 will be formed of a plurality of fibers 14. The randomly intermixing of the fibers 14 of the non-woven fabric 12 forms tortuous conduits 16 from a first surface 10 of the fabric 10 to a second surface 20 of the fabric 10. That is, the fibers 14 of the fabric 12, in combination, form a multitude of conduits through the fabric 10 as conventionally known. For the purposes of the present invention, the fabrics 14 should be placed below in such a way as to ensure that the conduits 16 through the fabric 12 are microporous conduits 16. Even though the fibers formed by low denier melt blowing are very suitable For this task, any type of fiber which can be arranged to ensure that the conduits 16 through the fabric 10 are microporous is sufficient. Those of ordinary skill in the art will readily recognize that typical microporous fabrics possess a multitude of such conduits per square inch. The fabric 10 is configured so that a particle 22 of a material which is a microbial adsorbent is positioned at some point along the length of the conduit 16 between the first surface 18 of the fabric 10 and the second surface 20 of the fabric 10. In most cases, the placement of the fibers 14 will be controlled so that the conduits 16 will be dimensioned in such a manner as to allow the passage of water vapor through the fabric 10. That is, the fabric 10 is breathable. In particular, a part of the microporous conduit 16 is defined by the microbial adsorbent 22 so that the microbes (not illustrated) which attempt to pass through the fabric 10 through a conduit 16 must pass in a close proximity to the microbial adsorbent 22. This arrangement allows the microbial adsorbent 22 to veto the microbes by adsorbing them and prohibiting their passage through the fabric 10 while still retaining the breathability of the fabric 10.

In some embodiments, the thermoplastic material 12 can be selected from the group including polyolefins, polyamides, polyesters and copolymers and blends in any combination of these and / or other suitable materials. For example, the polyolefin can be selected from the group consisting of polypropylenes, polyethylenes, polybutylenes and copolymers and mixtures thereof. The polyethylene can be a linear low density polyethylene.

By specifically making the type of microbial adsorbent 22 present in the fabric 10, the fabric 10 can be adapted to adsorb a wide variety of pathogens. For example, the fabric 10 can be made to act as a filter for viruses, bacteria, cysts and / or nematodes. Of course, the fabric 10 can be adapted to adsorb specific types of viruses, bacteria, cysts and / or nematodes depending on the use to which it is to be assigned. The use of a specific pathogen adsorbent easily achieves this result.

In certain embodiments, the fabric 10 can be designed to not only act as a filter (adsorbent) to the microbes as a result of the presence of the microbial adsorbent 22 but can also be designed to act as a physical (mechanical) barrier to the liquids that They try to pass through it. For this purpose, the microbial adsorbent 22 used can be an inflatable one, which in the presence of a generally aqueous liquid, can increase its volume by at least 1.5 times in no more than 120 seconds. For example, the microbial adsorbent 22 may be one which, in the presence of a generally aqueous liquid, increases in volume by at least 1.5 times in no more than 60 seconds. More particularly, the microbial adsorbent 22 can be one which, in the presence of a generally aqueous liquid, increases in volume by at least 1.5 times in no more than 15 seconds. Even more particularly, the microbial adsorbent 22 can be one which, in the presence of a generally aqueous liquid, increases in volume by at least 2 times in no more than one second. In the event that such microbial adsorbent 22 is used, the adsorbent 22 will increase, upon contact with the generally aqueous liquid, its size and swell. The swelling serves to block the microporous conduit 16 which is in close proximity to the inflatable adsorbent 22. The blocking of the conduit 16 creates a physical barrier within the microporous conduit 16 with the consequence that no liquid will pass through. the same. Therefore, a physical or mechanical barrier (dam) is formed in the duct 16 which closes the duct 16. The net result of this mode is that the cloth 10 is "intelligent" in the sense that it breathes and allows to the water vapor passing through the fabric 10 that has not received a liquid insult. The microbial adsorbent 22 within the fabric 10 constantly vents pathogens such as viruses and bacteria so that they can not pass through the fabric even though it is capable of allowing the passage of water vapor. However, upon receiving a liquid insult, the fabric seals itself only in the area of the insult in order to prevent the passage of the liquid through it. Through this the fabric 10 remains breathable because there is the presence of numerous other micropores 16 which have not been blocked. A specific example of an inflatable microbial adsorbent 22 is bentonite and, in particular, sodium bentonite.

Figure 2 illustrates an alternate form in which the physical blockage of the conduit 16 can be obtained, if the microbial adsorbent 22 which is desired to be used does not have the capacity of swelling (increase its size) which is that of the fabric 10 may also include a charge of another particulate material 24, which in itself, swells in the presence of a generally aqueous liquid. In some modalities, the particulates of the inflatable material 24 and of the microbial adsorbent 22 can be incorporated into the fabric 10 in an agglomerated form so that each individual particle contains some of the non-inflatable microbial adsorbent 22 and some of the inflatable material 24. In either of these embodiments the inflatable material 24 is one which can increase its volume by at least 1.5 times in no more than 120 seconds. For example, the inflatable material 24 may be one which in the presence of a generally aqueous liquid, increases in volume by at least 1.5 times in no more than 60 seconds. More particularly, the inflatable material 24 can be one which in the presence of a generally aqueous liquid, increases in volume by at least 1.5 times in no more than 15 seconds. Even more particularly, the inflatable material 24 may be one which, in the presence of a generally aqueous liquid, increases in volume by at least 2 times in no more than 1 second. Specific examples of such inflatable materials 24 can be used in conjunction with a non-swelling microbial adsorbent 22 including, without limitation, kaolins and diatomaceous earth. The earth diat acea can be treated, as known to those skilled in the art as to be positively charged. A restriction in this use is that the microbial adsorbent 22 and the inflatable material 24 must both be exposed to the conduit 16 so that each performs its respective functions.

The microbial adsorbent 24 can be any of such adsorbents 22 which is compatible with the fiber-forming material that is being used. In some embodiments the microbial adsorbent 22 is a heavy metal. For example, heavy metal can be silver.

In other embodiments, the microbial adsorbent 22 may be a metal salt. For example, the metal salt can be a polyvalent metal salt insoluble in water. The water-insoluble polyvalent metal salt can be a salt of a metal selected from the group of metals that includes Group IB, Group IIA, Group IIB, Group IIIA, Group IVB, Group VIB. More particularly, the metal can be selected from the group including iron, aluminum, lead, magnesium, silver, calcium and alloys of one or more of iron, aluminum, lead, magnesium, silver and calcium. The salt can be selected from the group including hydroxides, phosphates, chromates, oxides and peroxides. For example, the salt can be selected from the group including one or more of ferric hydroxides, ferrous hydroxides, aluminum hydroxides, magnesium hydroxide, magnesium oxide, magnesium peroxide, lead chromate and calcium hydroxide.

In some embodiments, the microbial adsorbent 22 can be selected from the group including colloidal clays. For example, the colloidal clay may be a bentonite such as sodium bentonite and / or calcium bentonite. In some embodiments, colloidal clay can be a hectorite.

The microbial filter fabric 10 of the present invention can advantageously be formed in a wide variety of articles where it is desired to have a material which allows the passage of, for example, water vapor but which prohibits the passage of microbes to through them. For example, the article may be a garment such as a surgical gown, foot protectors, face masks, head and hair coverings, aprons, sacks, pants, gloves, coveralls and generally talking, all the clothes for the operating room.

Alternatively the fabric 10 can be incorporated into a product such as, for example, a sterile wrapping material which is used to keep the sterile field around the doctor's instruments until they are used in an operation.

Similarly, the fabric 10 of the present invention can be conveniently formed or incorporated into a surgical drape for use on a patient during an operation.

The fabric 10 of the present invention can be made by a wide variety of methods known to those skilled in the art. A method for forming the film 10 is described in detail in U.S. Patent No. 4,100,324 entitled "Non-Woven Fabric and Method for Making the Film" and issued July 11, 1978 in the name of Richard A Anderson, Robert C. Sokolowski and Kurt W. Ostermeier. This application is specifically incorporated herein by reference in the present application and in its entirety. The fabrics 10 of the present invention can be formed using this process merely by replacing the microbial adsorbent particles 22 as the additive for the fiber-forming stream. All the other steps in the process remain essentially the same. Of course, the selected microbial adsorbent 22 desirably will not chemically interfere with or adversely affect the extruded fibers 14 and will have the ability to be relatively uniformly dispersed throughout the fibers 14 during their formation.

Alternatively, the microbial adsorbent particles 22 can be added to the thermoplastic material prior to extrusion through the die tip to form the fibers. In this embodiment, it is necessary that the moisture content of the microbial adsorbent 22 be maintained at 1%, by weight, or less so that a satisfactory extrusion occurs. Generally speaking, these microbial adsorbent particles 22 which they extrude will have an average particle size in the range of from about 0.1 to about 7 microns. Of course, the maximum particle size will depend on the final diameter of the fibers 14 to be formed. Typically, the fabric 10 will contain at least about 30% by weight of the fabric of the adsorbent 22.

Figure 3 shows schematically, in greater detail, a process for forming a fabric 10 according to the teachings of the present invention. This process is more fully described in U.S. Patent No. 4,663,220. The entirety of this patent is incorporated herein by reference. The fabric 10, in this embodiment, is formed of a nonwoven fabric formed by meltblowing 12 which may include essentially continuous microfibers 14. Alternatively, the microfibers 14 may be discontinuous, as is known to those skilled in the art. Whether the fibers 14 are continuous or discontinuous depends on a variety of process variables which include, for example, the speed of the attenuating gas, the temperature of the attenuating gas and the volume of the attenuating gas that passes. through the air ducts in a given period of time. The melt-blown fibers 14 are formed by means of a conventional meltblown matrix 26 and are deposited on the surface of a foraminous web 28. Other foraminous arrangements such as a drum arrangement can be used. One or more vacuum boxes (not shown) are typically located below the surface of the foraminous web 28 and between a pair of rollers 30 one of which is shown in Figure 3. The meltblown matrix 26 is supplied with a thermoplastic material, which is to be formed in the fibers 14 by means of a conventional extruder arrangement (not shown) through a hole. As is well known to those skilled in the art, the meltblown matrix 26 is also provided with pressurized air in the holes 34a and 34b. Then, the microfibers 14 are ejected from the meltblown matrix 26 and collected as a fibrous non-woven microporous fabric 12 on the surface of the web 28 which is moving as indicated by the arrow. The vacuum boxes assist in retaining the microfibers 14 on the surface of the web 28. Typically, the tip of the meltblown matrix 26 is from about 4 inches to about 24 inches from the surface of the web. endless foraminous 28 on which the microfibers 14 are collected. The entangled microfibers thus collected 14 form a coherent fibrous, microporous nonwoven fabric 12, for example, cohesive, which can be removed from the foraminous endless band 28 by means of a pair of pinching rollers (not shown) which may be designed to compress the entangled fibers 14 of the fabric 12 together to improve the integrity of the fabric 12. Then, the fabric 12 may be transported by means of a conventional arrangement to a roll of rolled up (not shown) for storage. Alternatively, the fabric 12 can be directly removed from the web 28 by a winding roller. In some embodiments the fabric 12 may be patterned as by ultrasonic etching equipment (not shown) or other etching equipment, such as, for example, the pressure clamping point formed between an anvil roller and heated calender. (not shown).

Figure 3 illustrates that the discrete particles of the microbial adsorbent are incorporated into the stream of fibers formed by meltblown 14 after the ejection of the fibers 14 from the meltblown matrix 26 but before the deposition of the fibers 14 on the web 28. If the microbial adsorbent 22 is one which does not swell and it is desired that the fabric 10 being made have the ability to form a mechanical barrier to insults of liquid, additional particulates of materials can conveniently be added. fibrous which have the ability to swell and which are added to the fiber stream at this point in the process. For example, it may be desirable to incorporate one or more types of inflatable materials such as superabsorbent materials., particulates or fibrous or wood pulp fibers or particulates within the fibers 14. Mixtures of two or more such fibers or particulates may be incorporated. This type of apparatus is conventionally referred to by those skilled in the art as a "coformation" apparatus. The coformation generally refers to the process of adding fibers and / or particulates to the stream of the newly formed fibers 14 before depositing on the web 28 and its subsequent formation inside a non-woven fabric 12.

Figure 3 illustrates that, after the formation of the microfibers 14, a stream of particulates of a microbial adsorbent 22 is injected in a generally uniform manner into the stream of microfibers 14. As previously stated, in some embodiments the adsorbent microbial 22 may be in the form of a fiber as opposed to the particulate form. The distribution of the microbial adsorbent particulates 22 generally uniformly through the microfiber stream 14 is preferably achieved by fusing a secry gas stream (not shown) containing the microbial adsorbent particulates 22 with the microfiber stream 14. The apparatus for achieving this fusion includes a conventional particulate injection system 36 which receives the particulates 22 in a hopper 38. The particulate injection system 36 brings the particulates 22 into the melt blowing stream of fibers 14 through a forming nozzle or duct 40. The particulates 22 are carried through the nozzle 40 by means of the secry stream of pressurized air.

The height 42 of the duct or forming nozzle 40 with respect to the tip of the die 26 can be adjusted to vary the properties of the shaped product. The values of the height 42 and the distance 44 will also vary with the particular microbial adsorbent 22 being added to the microfibers 14. The width of the duct or forming nozzle 40 and the length to which the duct extends or the forming nozzle 82 from the particulate injection system 36 will have to be adjusted in order to obtain an optimum distribution of the particulates 22 through the stream of meltblown microfibers 14. Preferably, the length of the duct or the Forming nozzle 40 should be as short as the design of the equipment allows.

Figure 3 further illustrates that the gas stream carrying the particulates 22 is desirably moving in a direction which is generally perpendicular to the direction of movement of the stream of the microfibers 14 at the melting point of the two gas streams. Other melting angles of the two currents can be used. The velocity of the gas stream carrying the particulates 22 is usually adjusted so that it is less than the velocity of the gas stream which attenuates the microfibers 14. This allows the currents, upon merging and with the integration thereof. , to flow in essentially the same direction as that of the microfiber stream 14. Indeed, the fusion of the two streams is preferably achieved in a manner which is somewhat like an aspiration effect whereby the stream of particulates 22 is It is also preferred that the speed difference between the two gas streams be such that the particulates 22 are integrated into the microfibers 14 in a turbulent manner so that the particulates are completely mixed with the particles. Microfibres 14. In general, the increase in the speed difference between the two currents produces a more homogeneous integration of the particulates 22 to inside the microfibers 14, and decreases in the speed difference between the two streams are generally expected to produce concentrated areas of the particulates 22 within the microfibers 14. Generally, for increased production rates it is desired that the gas stream carries and attenuates the stream of microfibers 14 having an initial high velocity, for example, from about 200 feet to about 1000 feet per secand for the gas stream which carries the particulates 22 having an initial low velocity, for example, from around 50 to about 200 feet per sec Of course, after the gas stream that carries and attenuates the extruded thermoplastic material inside the microfibers 14 leaves the meltblown matrix 26 it immediately expands and decreases in velocity.

With the fusion and integration of the stream of microbial adsorbent particulates 12 into the stream of microfibers 14 to uniformly distribute the particulates 22 uniformly through the stream of the meltblown fibers 14, as discussed above, forms a running area composed of microfibers 14 and particulates 22. Microfibers 14 may still be semi-squeezed and sticky at the time of incorporation of particulates 22 into microfibers 14, and in such a situation, particulates 22 are not only they entangle mechanically within the microfibers 14 but also thermally bond to the microfibers 14. However, if the microfibers 14 are not semi-squeezed and sticky at the time of incorporation of the particulates 22 there, the particulates 22 will only be mechanically entangled within of microfibers 14.

In order to convert the composite stream of microfibers 14 and particulates 22 into a microporous fibrous nonwoven fabric 12 of the microfibers 14 having the particulates 22 generally uniformly distributed therethrough and, if desired, attaching them to the microfibres 14 of the fabric 12, a collector device is located in the path of the composite stream. The collecting device may be the foraminous rotating band 28 illustrated in FIG. 3. A conventional vacuum array (not shown) helps retain the composite mixture of fibers 14 and particulates 22 on the outer surface of the band 28. Other devices of Harvesting are well known to those skilled in the art and can be used in place of the rotary band 28. For example, a porous rotary drum arrangement can be used. Then, the fabric 12 can be removed from the web 28 by a pair of clamping rollers (not shown) and stored on a conventional winding roller as previously discussed.

Those skilled in the art will readily recognize that numerous variations of these processes may be possible. For example, instead of using the conventional coformation apparatus, the microbial adsorbent particulates or fibers can be extruded directly through the matrix 26. In this embodiment, the particulates 22 will be incorporated directly into the fabrics 14. In some In these embodiments, the resulting fabric will include one or more fibers 14 having an outer surface. In some embodiments the fabrics 14 would define at least one microporous conduit 16 allowing communication through the fiber 14, between a first part of the outer surface and a second part of the outer surface of the fiber 14. As with the previous embodiments , a part of the microporous conduit will be defined by the microbial adsorbent 22. Alternatively, in other embodiments, the fibers 14 will have an outer surface which defines a concavity. In these modalities, the part of the outer surface which defines the concavity is, in itself, defined by the microbial adsorbent.

In some embodiments, it may be desirable to form a laminate of the fabric 10 of the present invention and one or more other materials. Such a laminate may have the combined attributes of all the individual layers. For example, the laminate can have a cloth-like appearance and feel, be breathable like the fabric and still be able to prevent the passage of the microfibers therethrough. Of course the term laminate is seen as including the embodiments of having two, three or more discrete and separate layers conventionally joined together by means of conventional lamination processes.

It should be understood that variations and modifications of the present invention can be made without departing from the scope of the invention. It should also be understood that the scope of the present invention should not be construed as limited to the specific embodiments described herein but only in accordance with the accompanying clauses when read in the light of the foregoing description.

Claims

R E I V I N D I C A C I O N S

1. A fabric defining a first surface and a second surface and comprising: a plurality of fibers which define at least one microporous conduit allowing communication through the fabric, between the first and second surfaces; Y wherein a part of the microporous conduit is defined by the microbial absorbent.

2. The fabric as claimed in clause 1, characterized in that the fabric is formed of at least one material selected from the group consisting of polyolefins, polyamides, polyesters and copolymers and blends in any combination thereof.

3. The fabric as claimed in clause 2, characterized in that the polyolefin is selected from the group consisting of polypropylenes, polyethylene, polybutylenes and copolymers and mixtures thereof.

4. The fabric as claimed in clause 3, characterized in that the polyethylene is a linear low density polyethylene.

5. The fabric as claimed in clause 1, characterized in that the microbial adsorbent is adapted to adsorb at least one type of virus.

6. The fabric as claimed in clause 1, characterized in that the microbial adsorbent is adapted to adsorb at least one type of bacteria.

7. The fabric as claimed in clause 1, characterized in that the microbial adsorbent is adapted to adsorb at least one type of cyst.

8. The fabric as claimed in clause 1, characterized in that the microbial adsorbent is adapted to adsorb at least one type of nematode.

9. The fabric as claimed in clause 1, characterized in that the microbial adsorbent is adapted, in the presence of a generally aqueous liquid, to increase its volume by at least 1.5 times in no more than 120 seconds.

10. The fabric as claimed in clause 1, characterized in that the microbial adsorbent is adapted, in the presence of a generally aqueous liquid, to increase its volume by at least 1.5 times in no more than 60 seconds.

11. The fabric as claimed in clause 1, characterized in that the microbial adsorbent is adapted, in the presence of a generally aqueous liquid, to increase its volume by at least 1.5 times in no more than 15 seconds.

12. The fabric as claimed in clause 1, characterized in that the microbial adsorbent is adapted, in the presence of a generally aqueous liquid, to increase its volume at least twice in no more than 1 second.

13. The fabric as claimed in clause 1, characterized in that the fabric further comprises an inflatable material which defines a part of the conduit and which is adapted, in the presence of a generally aqueous liquid, to increase its volume at minus 1.5 times in no more than 120 seconds.

14. The fabric as claimed in clause 1, characterized in that the fabric further comprises an inflatable material which defines a part of the conduit and which is adapted, in the presence of a generally aqueous liquid, to increase its volume at minus 1.5 times in no more than 60 seconds.

15. The fabric as claimed in clause 1, characterized in that the fabric further comprises an inflatable material which defines a part of the conduit and which is adapted, in the presence of a generally aqueous liquid, to increase its volume at minus 1.5 times in no more than 15 seconds.

16. The fabric as claimed in clause 1, characterized in that the fabric further comprises an inflatable material which defines a part of the conduit and which is adapted, in the presence of a generally aqueous liquid, to increase its volume at minus 2 times in no more than 1 second.

17. The fabric as claimed in clause 16, characterized in that the microbial adsorbent is attached to the inflatable material.

18. The fabric as claimed in clause 1, characterized in that the microbial adsorbent is a heavy metal.

19. The fabric as claimed in clause 18, characterized in that the heavy metal is silver.

20. The fabric as claimed in clause 1, characterized in that the microbial adsorbent is a metal salt.

21. The fabric as claimed in clause 20, characterized in that the metal salt is a polyvalent metal salt insoluble in water.

22. The fabric as claimed in clause 21, characterized in that the water-insoluble polyvalent metal salt is a salt of a metal selected from the group consisting of the metals of Group IB, Group IIA, Group IIB, Group IHA , Group IVB, Group VIB.

23. The fabric as claimed in clause 22, characterized in that the metal is selected from the group consisting of at least iron, aluminum, lead, magnesium, silver, calcium and alloys of one or more of aluminum, lead, magnesium , silver and calcium.

24. The fabric as claimed in clause 21, characterized in that the salt is selected from the group consisting of hydroxides, phosphates, chromates, oxides and peroxides.

25. The fabric as claimed in clause 24, characterized in that the salt is selected from the group consisting of one or more of ferric hydroxides, ferrous hydroxides, aluminum hydroxides, magnesium hydroxide, magnesium oxide, magnesium peroxide, lead chromate and calcium hydroxide.

26. The fabric as claimed in clause 1, characterized in that the microbial adsorbent is selected from the group consisting of colloidal clays.

27. The fabric as claimed in clause 26, characterized in that the colloidal clay is selected from the group consisting of bentonite and hectorite.

28. The fabric as claimed in clause 27, characterized in that the bentonite is sodium bentonite.

29. The fabric as claimed in clause 27, characterized in that the bentonite is calcium bentonite.

30. The fabric as claimed in clause 1, characterized in that the fabric is a non-woven fabric.

31. The fabric as claimed in clause 1, characterized in that the fabric is a woven fabric.

32. The fabric as claimed in clause 30, characterized in that the non-woven fabric is a fabric joined by spinning.

33. The fabric as claimed in clause 30, characterized in that the non-woven fabric is a melt blowing fabric.

34. An article that 'comprises the fabric as claimed in clause 1.

35. The article as claimed in clause 34, characterized in that the article is a pledge.

36. The garment as claimed in clause 35, characterized in that the garment is suitable for the dressing room of the operating room.

37. The garment as claimed in clause 36, characterized in that the garment is selected from the group consisting of surgical gowns, foot protectors, face masks, head and hair covers, aprons, sacks, pants, gloves and coveralls.

38. The article as claimed in clause 34, characterized in that the article is a sterile envelope.

39. The article as claimed in clause 34, characterized in that the article is a surgical drape.

40. A fabric that includes a microbial adsorbent, the fabric comprises at least one fiber having: an exterior surface; Y with the fiber defining at least one microporous conduit allowing communication, through the fiber, between the first part of the outer surface and the second part of the outer surface; Y wherein a part of the microporous conduit is defined by the microbial adsorbent.

41. A fabric that includes a microbial adsorbent, the fabric comprises at least one fabric having: an outer surface that defines a concavity; wherein a part of the outer surface defining the concavity is defined by the microbial adsorbent.

42. A laminate comprising the fabric as claimed in clause 1.

43. A laminate comprising the fabric as claimed in clause 40.

44. A laminate comprising the fabric as claimed in clause 41. SUMMARY A cloth is described which includes a microbial adsorbent and which is capable of providing a microbial barrier which is still capable of allowing the passage of water vapor. The fabric is formed of a plurality of fibers which define at least one microporous conduit which allows communication, through the fabric, between their respective first and second surfaces. In particular, a portion of the microporous conduit is defined by the microbial adsorbent so that the microbes attempting to pass through the fabric through the conduit must pass in close proximity to the microbial adsorbent. This arrangement allows the microbial adsorbent to veto the microbe by adsorbing it. The passage of the microbe through the fabric is prohibited. The laminates of the fabric with other materials are also described.