II. Background of the Invention: Hospital patient care generates considerable quantities of infectious medical waste in primary and acute care facilities. Such facilities have a need to provide various textile products to be used by physicians and other professionals, as well as for bedding ? draperies, towels, and similar items.

At one time, virtually all textiles used in such environments were reusable.

Reusable textiles were primarily made from woven fabrics of yards and the yards were compose of cotton or other natural fibers. However, synthetics were later developed which included fibers such as nylon, rayon and polyester. These synthetics were primarily spun from staple fibers and very little texturized synthetic filaments were in use at that time.

Approximately thirty years ago, disposable garments, covers, linens and drapes were introduced to the medical environment. When compare to the reusable garments, the disposables offered many cost-and time-saving features. For instance, hospitals were able to reduce or entirely eliminate their laundry facilities and the hospital had, for the first time, garments that exhibited significant barrer protection.

Barrier protection is important in hospitals to prevent unwanted contact of the wearer to harmful liquids, infections agents, and other bodily fluids.

Another significant drawback to reusable textiles was that they could not provide liquid barrier capabilities, especially after only a few laundry cycles. However, the average lifetime of a hospital reusable was approximately 18 laundry cycles.

Current disposables are generally non-woven in composition. For instance, carded stock is often chemically bonded into fabrics. Such carded webs are treated with adhesives or bonding agents and are then calendared to form"paper-light" materials. Carded webs have recently been replace by thermobond materials, which have a softer"hand,"but which have reduced cross-directional strength.

Further current disposables are produced from air-entangled and hydroentangled fibers which produce suitable fabrics. Such non-wovens are compose mostly of polypropylene fibers or from a polyester staple with cellulose wood pulp. These hydroentangled webs display the most textile-like hand, as well as a high degree of dimensional or cross-directional strength. Non-wovens of this class, such as SONTARAOO by Du Pont, are widely accepte for use in medical gowns and drapes.

Recently, the medical industry has begun reverting to the use of reusable items.

This trend arose because the disposable items produced significant infectious waste products. Originally, disposables were favored because they promoted anti-septic patient contact and decreased the potential for cross-infections between patients, a significant problem with cleanable, reusable textiles. However, various federal and state regulations have subsequently reclassified much of the disposable product as "infectious,"thereby making desirable the minimization of their use.

An average hospital patient produces 55 lbs. of medical waste per day.

Approximately 20 % of that waste is classifie as"infectious."The American Hospital Association and the Centers for Disease Control recommend immediate disposa of medical waste. Medical waste is considered an occupational hazard for health care workers, but is not considered an environmental safety problem. The most preferable way to contain infectious medical waste is to disinfect it at the point of generation and dispose of the treated medical waste with minimum handling and storagé on premises.

The need for an effective way to dispose of medical waste has been highlighted by the amendment made to 29 C. F. R. § 1910.1030 which provides for the federal regulation under the Occupational Safety and Health Act, 29 U. S. C. § 655,657 (the "Act") to control blood borne pathogens. Specifically, the Act calls for the establishment of an exposure control plan, the containment of specimens of blood or other potentially infectious materials and the general tightening of precautionary mesures to minimize the spread of disease. A safe and effective way to dispose of hospital waste is, therefore, highly desirable because it would facilitate compliance with the Act.

As a result, consumption of medical disposable woven or non-woven products has been growing at a rate of approximately 10% a year. In 1988, sales totaled approximately 1.155 billion dollars. As of the end of 1996, sales of medical disposable non-woven products are believed to have exceeded two and a half billion dollars. In the United States, there are at least 30 million surgical procedures performed each year.

After each surgical procedure, it is necessary that the operating theater be disinfected before a new procedure is performed to minimize any exposure the patients may bring to other patients or staff. This is particularly important in light of today's increasingly stringent regulations regarding occupational exposure to blood and bodily fluids.

Towels, songes, and gauze have been in use since the first days of surgical procedures. They are used either to manipulate tissue, absorb blood and other oxidants of the wound site, as well as being used to clean hands and assist in cleaning certain utensils used in various surgical procedures. Traditionally, towels, songes, and gauze have been made from cotton fibers, though in recent years attempts have been made to provide replacements from other fibers including polyesters, rayon and other staple materials. These fibers were chosen because of their relative availability and cleanliness as main-made materials. Cotton, on the other hand, is an agricultural material having volatile price and availability fluctuations. It has been noted that cotton replacements have, by and large, been unsatisfactory, although many attempts have been made to mimic the appearance of cotton.

Hospitals generally discard gauze, sponges and towels after each surgical use.

Disposa takes place in either a landfill or by incineration. In either case, the handling of such articles after use promotes the exposure of certain blood borne diseases to those employees who are charged with the responsibility for bagging and introducing such materials into the disposa process.

It is thus an object of the present invention to provide suitable towels, songes, gauze, as well as non-woven textiles capable of being dispose of after use while avoiding additional burdens being placed upon landfills and other disposa sites. It is yet a further object to provide suitable such articles which, after use, can be solubilized and substantially sterilized in a single operation.

Summary of the Invention The invention herein solves the drawbacks of the prior art by providing a synthetic textile suitable for use in the medical environment, such as for use as a towel, sponge, or gauze, which provides improved capability to absorbing harmful liquids and which provides a feel similar to that of traditional cotton fabrics.

The present invention provides a method for enhancing the absorbency, hand- feel, or both of an article (woven or non-woven) comprise of fibers, the method comprising subjecting the article to electron beam for a period of time sufficient to enhance the absorbency, hand-feel, or both of the article.

In another embodiment, the invention provides an article produced by subjecting a substrate comprise of fibers to electron beam treatment for a period of time sufficient to enhance the absorbency (i. e. , rate of absorbance and total absorbent capacity), hand-feel, or both of the substrate. The substrate may be any of the articles described above and elsewhere herein.

In yet another embodiment, the invention provides a method of disposing of an article produced by subjecting a hot-liquid soluble, cold-liquid insoluble substrate

comprise of fibers having a finish thereon to electron beam treatment for a period of time sufficient to enhance the absorbency, hand-feel, or both of the substrate, the method comprising contacting the article with a hot liquid for a period of time sufficient to disperse or dissolve the article. The article may be any of the articles described above and elsewhere herein.

Additional avantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The avantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appende claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

Detailed Description of the Preferred Embodiments The present invention may be understood more readily by reference to the following detailed description of preferred embodiments of the invention.

Before the present methods and apparatuses are disclosed and described, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. It must be noted that, as used in the specification and the appende claims, the singular forms"a,""an"and "the"include plural referents unless the context clearly dictates otherwise.

Throughout this application, where publications are referenced, the disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which this invention pertains.

As used herein, the term"hot"is used to refer to temperatures above about body temperature, or 37 °C. More preferably,"hot"refers to temperatures above 40 go,

more preferably to temperatures above 45 °C, even more preferably to temperatures above SO °C, even more preferably to temperatures above 75 °C, and most preferably to temperatures above 90 °C. Similarly,"cold"is used to refer to temperatures below about body temperature, or 37 °C. More preferably,"cold"refers to temperatures below 30 °C, more preferably to temperatures below 25 °C, and even more preferably to temperatures below 20 °C.

As used herein, the term"surgical fabric"refers to a textile like woven or non- woven article suitable for use in an operating room or other hospital or patient care setting. Such fabrics inclue, but are not limited to towels, songes, gauzes, gowns, drapes, and masks.

As used herein, the term"hand-feel"refers generally to the undesirability of a fabric feeling slick or slimy to the touch as determined, inter alia, by the coefficients of friction of the fabric surface. For the purposes of the present invention, improved or enhanced hand-feel refers to the reduction of the slickness or sliminess feeling and similarly to the approximation of the feel of the fabric to the feel of cotton fabric of similar weave or knit.

As noted, the present invention pertains to fabrics such as towels, songes, and gauze and methods for the disposa of such fabrics. These fabrics are used primarily in the medical industry in hospitals, outpatient facilities, and home environments. At such facilities, towels, sponges and gauze, particularly in surgical theaters, generally come into contact with human bodily fluids such that disposa and disinfection has become a matter of major concern in light of the lack of biodegradability of prior products and the potential spread of human borne diseases such as hepatitis B and AIDS. However, it should be noted that the fabrics could be used for a myriad of other uses not restricted to the health care industry, including any uses where hand-feel, increased absorbency, or hot water solubility of the fabric is desirable.

The fabrics can be natural or synthetic absorbent fabrics. Without wishing to be bound by theory, the present invention is effective for improving absorbency, hand-

feel, or both of synthetic woven or nonwoven fabrics. Some such fabrics have been treated with processing chemicals that reduce the absorbency or degrade the hand-feel.

With such fabrics, it is often undesirable or uneconomical to attempt to remove the finishing compound by washing or other processing. Some such fabrics which may have a finish thereon include poly (vinyl) alcohol fabrics, rayon fabrics and polyester fabrics, as well as nylon, polyimide, cellulose, acrylic, or polyolefin fiber based fabrics. Without wishing to be bound by theory, it is believed that one of the many benefits of the electron beam treatment of the present invention is the alteration or removal of the spin finish compound or other chemicals that may have been added as processing aids, such as, but not limited to, lubricants, viscosity aids, and the like.

In order to cope with the of the medical environment in particular, suitable towels, sponges and gauze can be made from fibers comprising poly (vinyl) alcohol which is soluble in hot water only at temperatures above a predetermined temperature.

Higher solubilization temperatures are used to prevent inadvertent solubilization while still permitting convenient disposa by the disposa methods of the invention.

In one embodiment, the fabrics are made from yards made from a plurality of fibers of poly (vinyl) alcool. The yarn can be formed as either a staple or as filament made from poly (vinyl) alcool. This nontoxic, synthetic polymer is produced by alkali or acidic hydrolysis of polyvinyl acetate. The vinyl acetate monomer is produced by reacting either acetylene and acetic acid or ethylene, acetic acid and oxygen.

Poly (vinyl) alcohol can be manufactured as a water soluble or insoluble resin. Water soluble resins of poly (vinyl) alcohol can be hot and cold water soluble or hot water soluble only. The temperature at which poly (vinyl) alcohol dissolves is controlled by changing its degree of hydrolysis and its polymer crystallinity and orientation.

Poly (vinyl) alcohol fibers used for the present invention are formed by dissolving suitable hot water soluble polyvinyl alcohol resin into deionized or distille water to a 5 % to 15 % solids mixture, thereby creating a dope. The dope is then allowed to stand for a considerable amount of time, for example two weeks, for gel setting. It is desirable to maintain the dope free of microbial organisms because

poly (vinyl) alcohol is subject to microbial degradation while in solution. Maintenance of the dope, therefore, is accomplished via ultrafiltration, heating, or other means known to one of ordinary skill in the art of preservation of resin solutions. Anti- microbial agents such as ester phenolic derivatives such as salicylic or benzoic esters can be used.

After the above-described resin has been gel set, it is then filtered and forced through a spinneret and into a saturated solution of sodium sulfate nvherein the fibers are coagulated into a range of deniers of from 6 to 10. The fiber is then subjected to a drain2 between a 2: 1 and 5: 1 ratio, with a 4: 1 ratio being preferred and then the fiber is heat annealed to produce suitable hot water only soluble fibers. The fibers so produced are then either chopped into a staple between approximately 1"to 2"in length or are formed into two bundles which can then be stretch broken with a fiber length of I"to 6". These fibers are then formed into a yarn either by conventional cotton spinninP methods. woolen spinning methods or spun directly from the stretch broken tow. A preferred yarn size is between 60 to 0.5 singles, with up to four plies of each of these yards. The yards can be spin in the Z or S direction with a weaving twist multiple being preferred.

In addition, the above-described yarn can be colore. if desired. If colore, the yarn should be dope dyed in the resin solution. Pigments are useful that are insoluble in water to produce the highest quality light sublimentation and mark-off resistance.

Fabric can be formed by weaving or by other well known techniques. For example, yards can be intermingled in a perpendicular fashion or can be woven, or yards can be single knit, double knit, interlocked, warped knit, or crocheted, as desired. It is even possible to bypass the yarn formation method and produce a nonwoven fabric directly from the fiber which is commonly referred to as either air laid, dry laid, wet laid, hydroentangled, thermo bonded, or chemical bonded.

Generally, the non-woven fabrics of the present invention are made as follows.

A chosen amount of the polymer fibers are formed into a fabric layer of about 0.02 to 30 mil thickness or having a density of about 10-100 g/m'.

The woven fabrics of the invention are made from yards which are woven into fabrics using conventional weaving procedures. However, in order to be formed, the fibers which form such yards (as well as being used to form the non-woven fabrics) must be pretreated with a spin finish. As described herein, a"spin finish"is generally compose of three ingredients: an antistatic agent (e. g. , polyethylene oxide ("POE") alkylethersulfate sodium and alkylphosphate potassium), a lubricantiantifriction agent (e. g. , glyceryl stearate), and a cohesion agent (e. g., POE alkylether). However, the present invention is applicable to removal of other processing or weaving aids, such as, but not limited to, alkane hvdrocarbons. By way of example only, the components of the spin finish may be fomiulated as an 80/10/10 mixture of antistatic ; cohesionantifriction aent which is diluted with approximately an equal amount of water before application to,. e. g. , poly (vinyl) alcohol fibers. Even though the spin finish comprises only about 0.2 % to about 0.5 % by weight of the final yard, at least some of the components are hydrophobic and thus are believed to reduce absorbency and lead to poor hand-feel of woven fabrics of poly (vinyl) alcohol that have been treated with the spin finish. As a reference, poly (vinyl) alcohol fabric with such spin finish has an absorbency value of about 80 % and feels slick to the touch. On the other hand, cotton towels that have been washed and bleached (which removes and finishing agents thereon) have a superior absorbency value of 120 % for weaves compatible with surcical uses and do not suffer from slickness or otherwise poor hand- feel.

Unfortunately, unlike cotton, bleaching and washing of (un-sized) poly (vinyl) alcohol based fabrics, including, but not limited to, surgical fabrics, is not feasible because such procedures either solubilize or degrade the fabric unacceptably.

Therefore, the spin finish generally remains on the poly (vinyl) alcohol based fabrics . prior to the present invention, there was no practical and effective way to remove or alter the spin finish.

In accordance with the present invention, the above-referenced fabrics have been enhanced by the following procedures.

The procedures useful to the present invention involve processing the fabrics using electron beam treatment. Electron beam treatment ("E-Beam treatment") is a process whereby high energy accelerated electrons are caused to bombard a chosen substrate, thereby either altering the properties of the substrate (e. g., causing cross- linking of polymers) or performing some other generally useful purpose (such as sterilization). The details of electron beam processing are known in the art.

The electron beam treatment dosage level is preferably at least 0.5 MR (megarads) and can increase up to about 12.5 to 13.0 MR, where samples started to degrade. Generally, the determination of the dosage needed to treat a material is determined by testing various samples. The electron beam energy level can range from 1 Mev up to 15 MeV, with 4.5 to 10 MeV being preferred. Initial absorbency rates for samples treated with these dosages are summarized in the following Table I. The testing protocol involved a modifie AATCC 42 Impact Penetration Test. The test was performed by tilting a metal plate at a 45 degree angle, then placing a sample towel (16 pound, 27 inch, folded 4-fold) on the plate. 250 CC of water was then sprinkled down from 1 foot above the towel onto the towel. The water was allowed to penetrate the towel or run off the plate for 30 seconds at which time the plate and towel weight was measured. The weight of the plate and towel, before adding the water, was recorde prior to commencing each test.

Table I: Dosage MR 0 2.5 5 7.5 10 12.5 Absorbency 63 80 80 88 81 81 As shown in Table I, electron beam treatment of the poly (vinyl) alcohol fibers of the improved the absorbency of the towels compare to the untreated control.

Table 11 shows the initial absorbency readings for poly (vinyl) alcohol fiber fabricated towels treated with the above-described electron beam treatment procedure.

The data demonstrate increased absorbency of all fabrics that were electron beam a treated over the untreated substrate absorbency value of about 70 %. Dosage was conducted on a 4.5 Mev capable machine.

Table II: Sample # Pre weight (g.) Post weight (g.) Water Abs. (g) Abs... (%) 2x Samples 1 53.8 98.2 44.4 82.5 2 53.7 95.6 41.9 78.0 3 53.5 97. 5 44.0 82.2 4 53.5 95.6 42.1 78.7 5 53.0 97. 4 44.4 83.8 6 52.6 98.2 45.6 86.7 7 53.1 97.9 44.8 84.4 8 52.8 97.4 44.6 84.5 9 53.4 95.5 42.1 78.3 10 53.4 96.1 42.7 80.0 11 53.5 96.9 43.4 81.1 12 53.3 97.5 44.2 82.9 Avg. 53.3 97.0 43.7 82.0 Std. Dev. 0.36 1.02 1.22 2.70 4x Samples 1 53.2 101.4 48.2 90.6 2 53.3 101.5 48.2 90.4 3 53.4 98.3 44.9 84.1 4 53.3 98.7 45.4 85.2 5 53.3 95.8 42.5 79.7 6 53.3 103.1 49.8 93.4 7 53.3 103.8 50.5 94.7 8 53.8 105.5 51.7 96.1 9 53.9 100.6 49.7 97.6 10 53.8 102.1 48.3 89.8 11 51.0 100.3 49.3 96.7 12 53.9 103.5 49.6 92.0 Avg. 53.0 101.2 48.2 90.9 Std. Dev. 1.01 2.70 2.64 5.50 6x Samples 1 51.5 103.2 51.7 100.4 2 51.2 105.0 53.8 105.1 3 51.2 102.0 50.8 99.2 4 51.1 105.3 54.2 106.1 5 51.2 98.9 47.7 93.2 6 50.8 101.3 50.5 99.4 7 50.7 104.8 54.1 106.7 8 51.1 104.7 53.6 104.9

9 50.8 102.1 51.3 101.0 10 51.1 101.9 50.8 99.4 11 51.1 103.4 51.9 100.8 12 51.4 101.0 49.6 96.5 Avg. 51.1 102.8 51.7 101.1 Std. Dev. 0.26 1.95 1.99 4.05 Table II shows surprisingly increased absorbency for electron beam treatments above the inherent roll absorbency of about 70 %. In addition, without wishing to be bound by theory, it is believed one of the numerus benefits of the invention is that at least a portion of the spin finish or procession2 aids (such as alkane hvdrocarbons) have been degraded, volatilized or vaporized by the electron beam treatment and, therefore, the resulting fabric is more hydrophilic and exhibits increased absorbency.

The present invention therefore provides, in one embodiment, a method for enhancing the absorbency, hand-feel, or both of an article comprise of fibers, the method comprising subiecting the article to electron beam for a period of time sufficient to enhance the absorbency, hand-feel, or both of the article. In one embodiment, the fibers are synthetic fibers, such as, but not limited to rayon fibers, polyester fiers, poly (vinyl) alcohol fibers, nylon fibers. polyimide fibers. cellulose fibers, acrylic fibers, polyolefin fibers, or a mixture thereof. In another embodiment, the fibers are natural fibers, such as, but not limited to, cotton fibers.

The article may be a surgical fabric, such as, but not limited to, a gaze, towel, or drape. In addition, the article may be a mask or sponge.

In one embodiment, the article is hot water soluble and cold water insoluble. In a further embodiment, the article is comprise of poly (vinyl) alcohol fibers. In a still farter embodiment, the poly (vinyl) alcohol is only soluble in water at temperatures above 37 °C, more preferably above 50 °C, even more preferably above 70 °C, and even more preferably above 90 °C. In addition, in one embodiment, the poly (vinyl) alcohol comprises crystallized polyvinyl alcool. In a further embodiment the

poly (vinyl) alcohol fibers are produced by dope extrusion and treatment with heat and stretching. In a still further embodiment, the poly (vinyl) alcohol is a produced from a greater than 80% saponifie polyvinyl acetate, more preferably from a-relater than 99% saponifie polyvinyl acetate. In a further embodiment, the degree of polymerization of the poly (vinyl) alcohol of the fibers is from 300 to 3000, more preferably from 1300 to 2000. In yet another embodiment, the poly (vinyl) alcohol has a degree of crystallinity of at least 0.20, more preferably at least 0.70. In another embodiment, the poly (vinyl) alcohol has a degree of orientation of at least 0.20, more preferably at least 0.50.

In one embodiment. the electron beam treatment uses a dosage of from 0.5 to 13. 0 megarads and the electron beam treatment occurs at from 1 to 15 Mev. More preferably, the electron beam treatment uses a dosage of from 2.5 to 10.0 megarads and the electron beam treatment occurs at from 2.5 to 10.0 Mev.

In a further embodiment, the invention provides an article produced by subjecting a substrate comprise of fibers to electron beam treatment for a period of time sufficient to enfance the absorbency, hand-feel, or both of the substrat. The substrate may be any of the articles described above and elsewhere herein.

Another embodiment of the invention provides a method of disposing of an article produced by subjecting a hot-liquid soluble, cold-liquid insoluble substrate comprise of fibers having a finish thereon to electron beam treatment for a period of time sufficient to enhance the absorbency, hand-feel, or both of the substrate, the method comprising contacting the article with a hot liquid for a period of time sufficient to disperse or dissolve the article. In one embodiment, the liquid is water.

The article may be any of the articles described above and elsewhere herein.

The previous examples were put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compound articles claimed herein are made, used and evaluated, and are intended to be purely exemplary of the invention and are not intended to limit the scope of what the inventors regard as their invention. Efforts have been made to ensure accuracy with respect to numbers

(e. g., amonts, temperature, etc.) but some errors and deviations should be accounted for.Unless indicated otherwise, parts are parts by weight, temperature is ion'C and is at room temperature, and pressure is at or near atmospheric.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention being indicated by the followingclaims.