MXPA00004126A - Sterilization wrap, applications therefor, and method of sterilizing - Google Patents

Abstract

A method of preparing a sterilized nonwoven web, which method includes providing a nonwoven web;coating the nonwoven web with from about 0.005 to about 3 percent by weight, based on the weight of the web, of an antistatic agent;and exposing the coated nonwoven web to an oxidizing gas plasma. The antistatic agent is adapted to be free of a malodor after exposure of the coated nonwoven web to the oxidizing gas plasma. The antistatic agent may be further adapted to provide a sterilized nonwoven web having a hydrohead value as measured by Method 5514 of Federal Test Method Standard No. 191A which is at least 50 percent of the hydrohead value of the coated nonwoven web before exposure to the oxidizing gas plasma. The antistatic agent also may be adapted to provide a sterilized nonwoven web having a surface resistivity in ohms which is lower than the surface resistivity in ohms of the coated nonwoven web before exposure of the coated nonwoven web to the oxidizing gas plasma. The antistatic agent may be an alkali metal or ammonium salt of either a mono- or di-C3-alkyl phosphate in which the C3-alkyl moiety is an alkyl group containing three carbon atoms optionally substituted with hydroxy groups or a b-carbon substituted alkyl phosphate, a di(b-carbon substituted alkyl) phosphate, or a mixture of two or more of the foregoing. The invention also provides a fibrous sheet-like material, such as a barrier fabric, a sterilization wrap, a surgical garment, and medical procedure packs.

Description

STERILIZING WRAP, APPLICATIONS FOR STERILIZATION AND STERILIZATION METHOD This application is a continuation in part of the co-pending application No. 08 / 976,108 which was filed on November 21, 1997 and with the priority claimed in the provisional serial application No. 60 / 063,878, filed on October 31, 1997. , whose applications are incorporated herein by reference.

Background of the Invention The present invention relates to a knitted fabric which can be sterilized. More specifically, the present invention relates to a sterilization envelope The sterilization envelope is a barrier material which is impermeable to liquids and microorganisms while being permeable to gases. The sterilization wrap is typically manufactured in a roll form and subsequently converted into cut sheets of various sizes as required for such end users as hospitals, clinics and other health care providers. In order to minimize or avoid static build-up during the manufacturing and / or conversion processes, an antistatic agent is typically applied to the wrapper early in the manufacturing process. In general, the antistatic agent is dissolved or disposed in water and the resulting aqueous medium is applied to the fabric by any suitable method. For example, the aqueous medium can be applied by brushing or embedding and pressing.

The presence of an antistatic agent is also beneficial during the wrapping process. The items to be sterilized, such as surgical instruments, are typically placed in a suitable instrument carrying tray and the combination of instruments and the tray is wrapped, with, for example, two layers of sterilization wrap and layer. Upper is tapered to provide a sealed relationship. Therefore, the first shell is closed before the second shell is applied. This procedure is mentioned in the art as a sequential wrap. The presence of a static charge in the leaves can result in more than one leaf being taken at a time leading to inefficiency and sometimes at an increased cost in the wrapping process. However, the simultaneous wrapping can be used and involves wrapping two wrapping sheets at the same time. In either case, the wrap is designed to allow the entry of sterilants such as steam or ethylene oxide to sterilize the contents while presenting a barrier to entry of contaminants such as bacteria once the sterilization process is completed.

Antistatic agents are, of course, well known in the art. A commercially available antistatic agent which has been used extensively in the past is a mixture of dipotassium butyl phosphate and salts of potassium dibutyl phosphate. The material is available from DuPon Chemicals, of Wilmington, Delaware, and is described in United States Patent No. 3,821,021 issued to McMili as part of a class of antistatic agents. Such a class is defined by the formula MnR3_nP04 wherein M is selected from the group consisting of lithium, sodium, potassium and ammonium ions, represents an alkyl group containing from 3 to 5 carbon atoms, and n is selected from the integers 1 and 2. According to the patent, the preferred agents are those in which it represents the potassium ion, and the most preferred termination is a mixture of approximately equimolar amounts of potassium dibutyl phosphate and dipotassium butyl phosphate and which moieties of butyl are straight chain hydrocarbon groups, for example n-butyl groups.

When the most highly preferred finished of the above-mentioned patent is added to the envelope d sterilization and is treated by one of the most recently developed sterilization processes which uses a plasma of oxidizing gas, the envelope may exhibit one or more undesirable characteristics. First, there is frequently an acute, acidic odor in the wrapper (referred to hereinafter as a bad smell). The term "bad smell" is used here to mean any odor that is considered by those who use the wrap as being pleasant or objectionable. Secondly, the property of the envelope barrier, as measured by the hydro head values, is typically reduced. Third, the antistatic property of the envelope is also reduced, as measured by the surface resistivity; that is, the surface resistivity of the envelope after sterilization is greater than the resistivity of the surface prior to sterilization. Therefore, there is a need for an improved antistatic agent for a sterilization wrapper and which is to be exposed to an oxidising gas plasma.

Synthesis of the Invention The present invention is based on the discovery that replacing a mixture of approximately equimolar amounts of potassium dibutyl phosphate and dipotassium butyl phosphate with an antistatic agent adapted to be free of bad odor after exposure to a plasma oxidizing gas of a fabric Nonwoven or a sterilization wrap coated with an antistatic agent successfully reduces or eliminates odor. For example, the use of an antistatic agent which involves one or more C-3 alkyl mono-phosphate salts and / or one or more substituted mono-dialkyl phosphate salts of β-carbon, both defined hereinafter , the undesirable characteristics noted above are reduced or eliminated when the sterilization process involves exposing a sterilization envelope to an oxidizing gas plasm.

Therefore, the present invention relates to (j ^ k some of the difficulties and problems discussed above by providing a method for preparing a sterilized woven fabric.The method includes providing a non-woven fabric; coating the non-woven fabric with from around 0.005 to about 3% by weight, based on the weight of fabric, of an antistatic agent; and exposing the coated non-woven fabric to a plasma of oxidizing gas. The anti-static agent is adapted to be free from odors after exposure of the coated non-woven fabric. The agent The antistatic can also be adapted to provide a sterilized non-woven fabric having a hydro head value as measured by method 5514 of Standard Test Methods No. 191A which is at least 50% of the hydro head value of the coated nonwoven fabric before being exposed to oxidizing gas plasma. The antistatic agent may also be adapted to provide a sterilized nonwoven fabric having a surface resistivity in ohms which is lower than the surface resistivity in ohms of the coated woven fabric before exposure of the coated non-woven fabric to the oxidizing gas plasma.

By way of example, the antistatic agent can be an alkali metal or ammonium salt of a C3 alkyl mono- or di-phosphate in which the C3 alkyl moiety is an alkyl group containing 3 carbon atoms optionally substituted with hydroxy groups. The desirable members of this group are the ammonium and alkali metal salts of phosphat propyl, dipropyl phosphate, isopropyl phosphate and phosphat diisopropyl, or mixtures of two or more of the foregoing. For example, such salt may be a potassium salt.

As another example, the antistatic agent can be an alkali metal or ammonium salt of a β-carbon substituted alkyl phosphate, a di (substituted β-carbon) phosphate or a mixture of two or more of the above. The substituted β-carbon alkyl group in general can contain d from four to about seven carbon atoms. The desirable members of this group are the alkali metal and ammonium salts of isobutyl phosphate, diisobutyl phosphate, and d mixtures of the foregoing. For example, such salt may be a potassium salt.

Also, by way of example, the non-woven fabric can be a meltblown fabric. As another example, the meltblown fabric can be a component of a laminate. For example, the meltblown fabric can be between and joined to two fabrics bonded with yarn.

The present invention further provides a sterilization wrap which includes a non-woven fabric impermeable to water and permeable to gas coated with about 0.005 to about 3% by weight, based on the weight of fabric, of an antistatic agent. The antistatic agent is adapted, after exposure of the water-impermeable non-woven fabric coated to an oxidising gas plasma to be free of odors and to have a hydrocabez value as measured by method 5514 of the Federal Trial 191A which is at least 50% of the hydro head value of the waterproof nonwoven fabric coated prior to exposure to oxidising gas plasma. The antistatic agent in general can be that described so far.

By way of example, the non-woven fabric can be a melt blown fabric. As another example, meltblown fabric can be a component of a laminate. As yet another example, the meltblown web can be between and joined two fabrics bonded with yarn.

The present invention additionally provides a barrier fabric, a sterilization wrap and a surgical trim, each composed of a fibrous tip sheet material as described heretofore.

The present invention still provides a package of medical procedure which includes a fluid-permeable container having an exterior and an interior, one or more articles to be sterilized which are present inside the container, and one or more layers. of wrapping d sterilization surrounding the outside of the container in a sealing relationship. The sterilization wrapping includes a non-woven, water-impermeable and ga permeable fabric coated with from about 0.005 to about 3% po weight, based on the weight of the fabric, of an antistatic agent wherein the antistatic agent is adapted after the exposure of the water impermeable nonwoven fabric coated oxidizing gas plasma, to be free of a bad odor to provide a nonwoven fabric having a hydro head value as measured by method 5514 of Standard d Federal Test Method No. 191A after exposure to oxidizing gas plasma which is at least 50% hydrocarbon value of nonwoven fabric impervious to coated agu prior to exposure to oxidizing gas plasma. The antistatic agent can also be adapted to have a surface resistivity in ohms which is lower than the resistivity of the surface in ohms of the nonwoven fabric waterproof coated before exposure to oxidizing gas plasm. The antistatic agent and the non-woven fabric are as described thus far.

In a variation of the medical procedure package described above as a container having an exterior and an interior may have one or more items to be sterilized present inside the container, wherein at least a portion of the container comprises the waterproof and gas permeable non-woven fabric id described above.

Finally, the present invention provides a method for manufacturing a nonwoven fabric adapted to be sterilized by exposure to an oxidizing gauge plasma. The method involves providing a woven fabric and coating the non-woven fabric with from about 0.005 to about 3% by weight, based on the weight of the fabric of an antistatic agent. The antistatic agent is adapted to be free of a bad odor after exposure of the coated nonwoven fabric to the oxidizing gas plasma. The antistatic agent can also be adapted to provide a sterilized nonwoven fabric having a hydrocabez value as measured by method 5514 of Federal Test Method Standard No. 191A which is at least 50% of the value of the test. hydrohead of the non-woven fabric coated before exposure to oxidising gas plasma. The antistatic agent and the non-woven fabric are as described thus far.

Brief Description of the Drawings • Figure 1 is a water surface tension scheme, in 10"3 Newtons per meter, which contains various amounts of each of the three antistatic agents, two of which are antistatic agents of the present invention.

Figure 2 is a diagram of the hydro head values, in Newtons per square meter, of the n-woven fabrics treated with any of the two antistatic agents employed in Figure 1 and sterilized with u oxidising gas plasma according to the present invention, e against the location of the fabric in the sterilization chamber Figure 3 is a schematic of the surface resistivity values, in ohms per square inch (ohms by 6.45 square centimeters or cm2) of non-woven fabrics treated with any of the two antistatic agents employed in Figure 1 and sterilized with an oxidizing gauge plasma according to the present invention, against the location of the fabric in the sterilization chamber. 25 Detailed Description of the Invention As used herein, the term "antistatic agent" refers to a material or a mixture of two or more materials which, when applied to the surfaces of the fibers of which a non-woven fabric is composed, aid in the dissipation of the fabric. static charges from the surface of the fibers Therefore, an antistatic agent increases the electrical conductivity of the fibers, and, as a consequence of the electrical conductivity of the non-woven fabric.

As used herein, the term "coating" refers to coating the surfaces of the fibers or d the films with the antistatic agent, and / or to the location of the antistatic agent in the fiber to fiber interstices and / attachment points. The coating of all the fibers of which the non-woven fabric is composed is not necessarily required for all applications. In order to impart antistatic characteristics to a non-woven fabric, it may be sufficient to coat only those fibers which constitute a surface of the fabric.

The term "alkali metal" as used herein means the metals of the group of the Periodic Table of the Elements, for example lithium, sodium, potassium, rubidium, and cesium with the first three metals of the series having the most practical utility.

The term "hydro head value" is the value obtained according to method 5514 of the Federal Standard Test method No. 191A. The hydro head value is reported here as Newtons per square meter.

As used herein, "surface resistivity" means surface resistivity as determined in accordance with test method AATCC 76: 1972 (see also US Pat. No. 4,041,203 mentioned below). reported as ohms per square inch or simply ohms per square.The test utilizes a Model 610C electrometer (from Keithley Instruments, Inc., Cleveland, Ohio 44139) and a high model 240A DC voltage supply (from Keithley Instruments, Inc.) The test samples are balanced at 23 ° C and at 50% relative humidity for 24 hours.

The terms "phosphate", "phosphate ester" "alkyl phosphate" and similar terms, in both singula and plural, refer to alkyl esters of orthophosphoric acid (commonly called phosphoric acid), H3P04. Due to the fact that phosphoric acid is a tribasic Pv acid, mono-, di- and triesters are possible. The mono and diesters can exist in either the salt or acid form. In fact, the diesters are strongly acidic and are completely in the anionic (ionized) form at normal pH values.

As used herein in relation to one or more layers of sterilization wrapping surrounding the articles to be sterilized or to a container in which such article is located, the term "sealing ratio" means that each layer is tapered or sealed. another closed or sealed manner in order to preserve the barrier properties of each layer.

The term "non-woven fabric" is used herein to mean a fabric having an individual fiber structure which is interspersed in a generally random manner, not in an identifiable manner as in a woven fabric, and is intended to include any fabric non-woven For example, the term includes those prepared by well-known melt extrusion processes such as melt blowing, coformming and spin bonding. Tale processes are exemplified by the following references, with one of which is incorporated herein by this reference. (a) Meltblown references include, by way of example, the patents of the United States of America Nos. 3,016,599 issued to R.W. Perry, Jr., 3,704.19 awarded to J.S. Prentice, 3,755,527 awarded to J.P. Keller others, 3,849,241 awarded to R.R. Butin et al., 3,978.18 granted to R.R. Butin et al. And 4,663,220 granted to T.J Wisneski et al. See also the work "Superfine Thermoplastic Fibers", by V.A. and others, in Chemistry of Industrial Engineering, Volume 48, No. 8, pages 1342-1346 (1956); the obr of V.A. Wente et al., "Superfine Organic Fiber Manufacturing", Naval Research Laboratory, Washington DC, naval research laboratory report 4364 (111437 dated May 25, 1954, United States Department of Commerce, Office of Services Technicians, and the work of Robert R. Butin and Dwight T. Lohkamp, "Blowing with Fusion A One-Step Weaving Process for Nonwoven Products," Journal of the Pulp and Paper Industry Technical Association, volume 56, No. 4, pages 74-77 (1973); (b) references to coformmation (eg references describing a co-melt blowing process in which the fibers or particles are blended with the melt blown fibers as they are formed) include the United States of America patents numbers 4,100.32 granted to RA Anderson and others and 4,118,531 granted to E. R Hauser; Y (c) the references of the link with hilad include, among others, the United States patents of America numbers 3,341,394 granted to Kinney, 3,655,862 granted to Dorschner and others, 3,692,618 granted to Dorschner and others 3,705,068 granted to Dobo and others, 3,802,817 granted to Matsuk and others, 3,853,651 granted to Porte, 4,064,605 granted to Akiyam and others, 4,091,140 granted to Harmon, 4,100,319 granted to Schwartz, 4,340,563 granted to Appel and Morman, 4,405,297 granted to Appel and Morman, 4,434,204 granted to Hartman and others, 4,627.81 granted to Greiser and Wagner, and 4,644,045 granted to Fowells.

Other methods for preparing the non-woven fabrics are known and can be employed. For example, the term also includes non-woven fabrics prepared from relatively short fiber to form a fabric or sheet. The methods employed to prepare such fabrics include air placement, wet setting, carding, and the like. In some cases, it may be desirable or necessary to stabilize the non-woven fabric by known means, such as the bonding of the term term (for example, pattern bonding by application of heat and pressure), bonding through air, and hydroentangled The phrase "pattern bonding by application of heat and pressure" means any process by which a non-woven fabric is passed through a pressure point formed by a pair of opposed rolls. Either or both of the rollers may have an irregular regular surface pattern of continuous plains or grooves or isolated (discontinuous) projections. For example, the non-woven fabric can be patterned by applying heat and pressure in the ranges of from about 80 degrees centigrade to about 180 degrees centigrade and from about 15 to about 1000 pounds per linear inch (from from about 59-178 kilograms / centimeter), respectively, employing a pattern of from about 10 to about 1000 union region / square inch (from about 1-155 union region / square centimeter) covering from around to about 50% of the fabric surface area. Only the design patent of the United States of America number 239,566 granted to Vogt, the design patent of the United States of America number 264.51 granted to the representative of the known joining processes, is shown by way of example only. Rogers, the United States of America patent number 3,855,046 granted to Hansen and others, and the United States of America patent number 4,493,868 granted to Meitner.

The term "synthetic polymer fibers" is used herein to mean fibers composed of any synthetic polymer, usually thermoplastic which may be used to prepare the non-woven fabrics. Examples of the thermoplastic synthetic polymer include, by way of illustration only, capped polyacetals, such as poly (oxymethylene) opoliformaldehyde, poly (trichloroacetaldehyde), poly (n-valeraldehyde), poly (acetaldehyde), and poly (propionaldehyde); acrylic polymers such as polyacrylamide, poly (acrylic acid), poly (methacrylic acid), poly (ethy acrylate), and poly (methyl methacrylate); fluorocarbon polymers, such as poly (tetrafluoroethylene), perfluorinated ethylene propylene copolymers, ethylene tetrafluoroethylene copolymers, poly (chlorotrifluoroethylene), ethylene-chlorotrifluoroethylene copolymers), poly (vinylidene fluoride) poly (vinyl fluoride); polyamides, such as poly (6-aminocarboxylic acid) or poly (e-caprolactam), poly (hexamethylene adipamide), poly (hexamethylene sebacamide), and poly (11-amino-acid undecanoic); polyaramides, such as poly (imino-1,3-phenylene iminophthaloyl) or poly (m-phenylene isophthalamide); parilenes, ta as poly-p-xylylene and poly (chloro-p-xylylene); polyaryl ethers, such as poly (oxy-2,6-dimethyl-1, 4-phenylene) or poly (p-oxide phenylene); polyaryl sulfones, such as poly (oxy-1,4-phenylenesulfonyl-1,4-phenyleneoxy-1,4-phenylene-isopropylidene-1,4-phenylene) and poly (sulphonyl-1,4-f eni-1-eno-oxy) - 1,4-phenylenesulfonyl-4,4'-phenylene), and the like; polycarbonates, such as poly (bisphenol A) carbonate or poly (carbonyldioxy-1,4-phenylene isopropylidene-1,4-phenylene); polyesters such as poly (ethylene terephthalate), poly (tetramethylene terephthalate), and poly (cyclohexylene-1,4-dimethylene terephthalate) poly (oxymethylene-1,4-cyclohexylene-methyleneoxytephthaloyl); pol-aryl sulfides, such as poly (phenylene sulfides) poly (thio-1,4-phenylene); polyimides, such as poly- (pyromellimid-1,4-phenylene); polyolefins such as polyethylene, polypropylene, poly (1-butene), poly (2-butene), poly (1-pentene), poly (2-pentene), poly (3-methyl-1-pentene) and poly (4-) methyl-l pentene); vinyl polymers such as poly (vinyl acetate), poly (vinylidene chloride) and poly (vinyl chloride); diene polymer such as 1,2-poly-1,3-butadiene, 1,4-poly-1,3-butadiene, polyisoprene, and polychloroprene; polystyrenes, copolymers of the foregoing, such as copolymers of acrylonitrile-butadiene styrene (ABS).

Desirably, the non-woven fabric will be prepared from a synthetic polyolefin. In general, the term "thermoplastic polyolefin" is used herein to mean any thermoplastic polyolefin which can be used for the preparation of non-woven steels. Examples of the thermoplastic polyolefins include polyethylene, polypropylene, poly (1-butene), poly (2-butene), poly (1-pentene), poly (2-pentene), poly (3-methyl-1-pentene), poly (4-methyl-1-pentene) and the like.

Furthermore, such a term is intended to include mixtures of two more polyolefins and random and block copolymers prepared from two or more different unsaturated monomers. Due to its commercial importance, the most desired polyolefins are polyethylene and polypropylene.

As indicated above, the method of the present invention includes providing a non-woven fabric; coating the non-woven fabric with from about 0.005 about 3% by weight, based on the weight of the fabric of an antistatic agent; and exposing the non-woven fabric coated to an oxidizing gas plasma. The antistatic agent is adapted to be odor free after exposure of the coated nonwoven fabric. The antistatic agent can also be adapted to provide a sterilized nonwoven fabric having a hydro head value as measured by method 5514 of the Federal Test Method Standard No. 191A which is at least 50% of the value of hydrohead of the coated woven fabric before exposure to the oxidizing gauge plasma. The antistatic agent can also be adapted to provide a sterilized nonwoven fabric having a surface resistivity in ohms which is lower than the surface resistivity in ohms of the non-woven fabric coated prior to the exposure of the coated non-woven fabric. to the oxidizing gas plasma.

The antistatic agents of the present invention are best exemplified by two types of compounds. The first type includes alkali metal or ammonium salts of C3 alkyl mono- and di phosphates in which the C3 alkyl moiety is an alkyl group containing 3 carbon atoms optionally substituted with hydroxyl groups. Stated differently, the first group is composed of mono- and diesters of phosphoric acid with alcohols, diols and triols containing three carbon atoms. Examples of such alcohols, triol diols include propyl alcohol (or n-propyl alcohol), isopropyl alcohol (or 2-hydroxypropane), propylene glycol (or 1,2-hydroxypropane), trimethylene glycol (or 1,3-dihydroxypropane), glycerol ( or 1, 2, 3-trihydroxypropane). Therefore, the d ester portions of the first type of the antistatic agents are the 5-propyl or isopropyl group (for example 2-propyl), optionally substituted with 1 or 2 hydroxy groups. More particularly, the antistatic agents of the present invention include the leaving of ammonium or alkali metal of propyl ester of phosphoric acid,. or propyl phosphate; a dipropyl ester of phosphoric acid or a dipropyl phosphate; an isopropyl ester of phosphoric acid fl) isopropyl phosphate; a diisopropyl ester of phosphoric acid or diisopropyl phosphate; a 2-hydroxypropyl ether of phosphoric acid, or 2-hydroxypropyl phosphate; a di (2-hydroxypropyl) ester of phosphoric acid, or di (2-hydroxypropyl) phosphate; a 1-hydroxy-2-prop phosphoric acid ester, or 1-hydroxy-2-propyl phosphate; a di (1-hydroxy-2-propyl ester of phosphoric acid, or di (1-hydroxy-2-propyl) phosphate, a 3-hydroxypropyl ester of phosphoric acid, 3-hydroxypropyl phosphate, a di (3-hydroxypropyl) ester of acid phosphoric, or di (3-hydroxypropyl) phosphate; a 2,3-dihydroxypropyl phosphoric acid ester, or 2, 3-hydroxypropyl phosphate; bis (2,3-dihydroxypropyl) ester of phosphoric acid or bis (2,3-hydroxopropyl) phosphate; a 1,3-dihydroxy-2-propyl ester of phosphoric acid, or 1,3-dihydroxy-2-propyl phosphate; a bis (1,3-dihydroxy-2-propyl) ester of phosphoric acid, or bis (1,3 -dihydroxy-2-propyl) phosphate; and mixtures of two or more of the foregoing.

By way of example, the antistatic agent can be a mixture of alkali metal or ammonium salts of propi phosphate and dipropyl phosphate. For example, salts can be potassium salts. Also by way of example, the antistatic agent may be a mixture of alkali metal or d-ammonium salts of isopropyl phosphate and diisopropyl phosphate. Again by way of example the salts may be potassium salts.

The second type of compounds which exemplified the antistatic agents of the present invention and includes fl | alkali metal or ammonium salts of alkyl substituted phosphates with β-carbon, di (substituted β-carbon alkyl) phosphates or a mixture of two or more of the foregoing. The group of substituted alkyl of β-carbon in general may contain from four to about seven carbon atoms. The term β-carbon, refers, according to common practice, to the carbon atom immediately adjacent to the carbon atom where it is covalently bound to the phosphate oxygen atom. E carbon-ß can have either one or two substituents. How do you use Here, the term "substituent" means an atom other than hydrogen which is effective to minimize or prevent odor when the antistatic agent is present in a sterilization wrapping tissue which is sterilized in an oxidizing gas plasma. Examples of the 'suitable substituents Include, without limitation, such groups as methyl and ethyl; the hydroxymethyl; and similar.

Examples of the phosphates encompassed by the second type of compounds include, by way of illustration only, the alkali metal or ammonium salts of an isobutyl ester of phosphoric acid or of isobutyl phosphate; a diisobutyl d ester of phosphoric acid or diisobutyl phosphate, pentaerythritol mono and diesters of phosphoric acid or 3-hydroxy-2 bis (hydroxymethyl) propyl phosphate and bis [3-hydroxy-2,2 bis (hydroxymethyl) propyl] phosphate; 2-methyl-1-butyl phosphate; di (2-methyl-1-butyl) phosphate; 2, 2-dimethyl-l-butyl phosphate; bis (2,2-dimethyl-l-butyl) phosphate, 2,3-dimethyl-l-butyl phosphate; bis (2,3-dimethyl-l-butyl) phosphate; 2-ethyl-l-butyl phosphate; di (2-ethyl-1-butyl) phosphate; 2-methyl-1-pentyl phosphate; di (2-methyl-1-pentyl) phosphate 2, 2-dimethyl-1-pentyl phosphate; bis (2,2-dimethyl-l-pentyl) phosphate; 2, 3-dimethyl-1-pentyl phosphate; bis (2,3-dimethyl-l-pentyl) phosphate; and the like; and mixtures of two or more of the above.

By way of example, the antistatic agent can be a mixture of alkali metal or ammonium salts of isobutyl phosphate and diisobutyl phosphate. By way of example, the salts can be potassium salts.

In general, the non-woven fabric may be any non-woven fabric essentially composed of synthetic polymer fibers. For example, the non-woven fabric can be a melt blown fabric. As another example, the co-melt blown fabric can be a component of a laminate. For example, the non-woven fabric may include a first layer which is a non-woven fabric composed of synthetic polymer fibers and a second layer, adjacent to the first layer in a surface relationship to a laminar surface, which is a non-woven fabric. composite woven d synthetic polymer fibers. As another example, the woven fabric n can include a first layer having a first side a second side, a second layer adjacent to the first side of the first layer in a surface to surface relationship, and a third layer adjacent to the second side of the first cap in a surface to laminar surface relationship. Each woven fabric typically will be essentially composed of synthetic polymer fibers. For example, the synthetic polymer fibers of which the first, second and third layers are composed may be polyolefin fibers. For example, the polyolefin fibers can be polyethylene fibers, polypropylene fibers, or a combination thereof. The first layer can be a melt blown fabric and each of the second and third layers can be a spunbonded web. The laminate or any layer combination layer can be patterned by the application of heat pressure. The laminates also include one or more layers of non-woven fabrics with one or more layers of film.

The two-layer and three-layer laminates described above are known in the art and are often referred to as SM and SMS fabrics, respectively. See, for example, U.S. Patent No. 4,041,203 to Brock et al., Whose patent is hereby incorporated by reference in its entirety.

The coating in general can be achieved by any means known to those of ordinary skill in the art. By way of example, such means include, but are not limited to, embedding and pressure, the doctor blade, brushing, spraying, and direct and offset engraving printing.

The present invention further provides a fibrous sheet type material which includes a gas permeable and water impermeable woven fabric coated with from about 0.005 to about 3% by weight, based on the weight of the fabric, of an antistatic agent. . The antistatic agent is adapted, after the exposure of the nonwoven fabric to the water coated with an oxidising gauge plasma, to be free from bad odors and to have a hydroheat value as measured by method 5514 of the Standard d Method of Federal Test 191A which is at least 50 of the hydro head value of the non-woven fabric impervious to the coated agu exposed to the oxidising gas plasma. The antistatic agent in general can be that described hereinabove. The sterilization wrap may be a non-woven cloth or a laminate, also described herein above.

The present invention further provides a barrier fabric, a sterilization wrap and a surgical trim, each composed of the fibrous web-like material described above.

The present invention still further provides a package of medical procedure which includes one or more items to be sterilized and one or more layers of the sterilization wrap surrounding one or more articles to be sterilized in a sealing relationship. The medical procedure package can also include a The fluid-permeable container having an exterior and an interior, with one or more articles to be sterilized, being present inside the container. The sterilization casing includes a gas permeable waterproof nonwoven fabric coated with from about 0.005% to about 3% by weight, based on the weight of the fabric, of an antistatic agent, wherein the antistatic agent is adapted, after the exposure of the waterproof non-woven fabric coated to a plasma of oxidizing gas, to be free of a bad smell and to provide a n Woven having a hydro head value as measured by method 5514 of the Federal Test Method Standard No. 191 after exposure to oxidising gas plasma which is at least 50% of the hydro head value of woven fabric waterproof and coated before exposure to oxidizing gas plasma. The antistatic agent may also be adapted to have a surface resistivity and ohms which is lower than the surface resistivity and ohms of the nonwoven fabric impermeable to water coated before exposure to the oxidizing gas plasma. The antistatic agent and the nonwoven fabric are described hereinbefore.

In a variation of the medical procedure package described above, a container having an exterior and interior may have one or more items to be sterilized present inside the container, wherein at least a portion of the container comprises the fabric. non-woven id waterproof and gas permeable described above. Such a container is often referred to in the art as a peeling bag, one side of which is the above non-woven fabric. The container typically contains a single item that is to be sterilized.

Finally, the present invention provides a method for making a nonwoven fabric adapted to be sterilized by exposure to an oxidizing gauge plasma. The method involves providing a knitted fabric and coating the non-woven fabric with from about 0.005 to about 3% by weight, based on the weight of the fabric of an antistatic agent. The antistatic agent is adapted to be free of a bad odor after exposure of the coated nonwoven fabric to the oxidizing gas plasma. The antistatic agent can also be adapted to provide a sterilized nonwoven fabric having a hydrocabez value as measured by method 5514 of Federal Test Method Standard No. 191A which is at least 50% of the value of the test. hydrohead of the coated non-woven fabric before exposure to the oxidizing gas plasma. The antistatic agent and the non-woven fabric are as described thus far.

The present invention is further described by the following examples. Such examples, however, should not be considered as limiting in any way either in spirit or in the scope of the present invention.

Example 1 A thermally bonded laminate of a spunbonded melt-bonded yarn-bound (SMS) yarn was prepared essentially as described in U.S. Patent No. 4,041,203, see below. The tel linked with spin-blown with fusion-linked with spinning has a base weight of 48 grams per square meter or gsm. The melt-bonded spin-linked tel with yarn was treated with antistatic agents by the embed and squeeze method described in U.S. Patent No. 4,041,203. Three different antistatic agents were used: (1) antistatic agent A, which was supplied as a 50% by weight solution of dipotassium butyl phosphate and potassium dibutyl phosphate in approximately equimolar amounts (Zelec KC, DuPont Chemicals, Wilmington) , Delaware 19898); (2) Antistatic agent B, which was supplied as a solution of approximately 50% by weight of dipotassium propyl phosphate and dipropyl potassium phosphate in approximately equimolar amounts (Du Pon Chemicals); and (3) Antistatic agent C, which was supplied as a solution of approximately 50% by weight of dipotassium isopropyl phosphate and potassium diisopropyl phosphate and approximately equimolar amounts (Du Pont Chemicals).

Two levels of each of the antistatic agents A and B were applied to the fabric: (1) 0.1% by weight, and (2) 0.3% by weight. For a target level of 0.1% by weight antistatic agent on the cloth, the treatment solution was obtained by diluting the solution as supplied with hexanol and deionized water to give an antistatic agent and hexanol concentration in the treatment solution. of 0.22% po weight and 0.55% by weight respectively. The second objective level of 0.3% by weight was obtained in a similar manner, except that the final concentrations of antistatic agent and hexanol were 0.67% by weight and 0.55% by weight respectively. The antistatic agent C was applied at the target level of 0.2% by weight, with the concentrations of antistatic agent and hexanol in the treatment solution being 0.20% by weight and 0.55% by weight, respectively. In each case, the volume of work was 8 liters.

Each antistatic agent was applied topically to the fabric by passing the fabric at a rate of 40 feet per minute (about 20 centimeters per second) in the treatment solution and through a pressure point at a pressure of 60 pounds per second. square inch. The humid fabric was then dried by passing it sequentially over a series of 6 steam cans set at a temperature of about 113 ° C. A sample of the fabric was removed immediately after the pressure point in order to measure the humid collection on the cloth and calculate the percentage of added level of antistatic agent on a dry weight basis.

The antistatic properties of the treated fabrics were determined by the surface resistivity test. Five duplicates were measured and the average value was calculated. The effectiveness of the fabrics as a liquid barrier was determined by the hydrohead test and described. Five duplicates of this test were taken and averaged. The treated fabrics are summarized in Table 1 and the results are summarized in Table 2. In Table 1, three antistatic agents are represented by the letters A, B and C.

Table 1 Summary of Treated Fabrics Table 2 Surface Resistivity and Hydrohead Data c In ohms per square inch (to convert to ohms per square centimeter, divide by 6.45) In Newtons per square meter.

When comparing the data in Table 2 for samples 1-2 to 1-6 with the data for sample 1-1, it can be seen that both antistatic agents B and C provide acceptable surface resistivity properties with a significantly lower reduction of the hydro head values unlike the antistatic agent A.

Example 2 Several of the fabrics produced in the Example were sterilized by oxidizant gas plasma essentially in accordance with U.S. Patent No. 4,643,876 issued to Jacobs et al., Whose patent is incorporated herein by reference in its entirety. Ta sterilization employed a hydrogen peroxide plasma and a STERRAD ^ ™ 100 sterilization system (Advanced Sterilizatio Products, of Irvine, California 92718); the procedures recommended by the manufacturer were followed.

Mass spectrometry / ga chromatography (GC / MS) was used to analyze the fabrics with respect to odoriferous chemicals. Samples 1-1, 1-3 and 1-5 of Example 1 (Table 1) were analyzed before and after exposure to plasma STERRAD1 ^ 0 * gas. During the GC / MS analysis, about 5 grams of the cloth were placed in a spray tube and purged with a helium stream at room temperature for 15 minutes. The volatile chemicals purged were identified by the GC / MS technique according to known accepted procedures. Table 3 shows a summary of the results.

Table 3 Summary of GC / MS Data The data in Table 3 strongly suggest that methyl vinyl ketone, a chemical with a strong pungent odor (Indic Merck) is responsible for the unpleasant odor that was observed when the fabric treated with the antistatic agent A was exposed to a plasma of oxidizing gas (sterilization procedure STERRAD ^ 8-).

It can be noted that the observation of an olo associated with the plasma sterilization of oxidising gas of the fabric to which the antistatic agent A had been applied can be concentration dependent. For example, when a commercially available sterilization wrap has been applied to an antistatic agent A at a level of 0.025% by weight (KIMGUARD ULTRA * 12 ^, from Kimberly-Clark Corporation d Roswell, Georgia 30076) was sterilized by the procedure STE RAD "^^, no volatile chemicals were detected.

Example 3 The surface tension data was collected in an effort to explain the unexpected hydro head results obtained with the use of antistatic agents B and C. The surface tension of the water with various amounts of antistatic agent A, B or C added as measured with a Fisher 20 surface tensiometer using a nuoy ring platinum-iridium (from Fisher Scientific Company, d. Pittsburgh, Pennsylvania). For these measurements, about 80 milliliters of distilled deionized water were placed in a 100 ml Pyrex beaker. After an initial surface tension measurement was taken, one drop of the antistatic agent solution was added to the water and the resulting solution was stirred for 5 minutes. The surface tension of the new solution was measured then, and the procedure was repeated until it was completed. The Table summarizes the surface tension data for antistatic agents A, B and C.

Table 4 Summary of Surface Voltage Data In order to better illustrate the effects of the antistatic agents on the surface tension of the water, the data in Table 4 were drawn as line graphs as shown in Figure 1. It can be seen from the surface tension data of the Table 4 and Figure 1 that antistatic agents B and C unexpectedly depress the surface tension of the water with less than what antistatic agent A does. Therefore, antistatic agents B and C are antistatic treatments of less active surface. e comparison with the antistatic agent A.

Example 4 The fabrics treated with a target level of 0.1% by weight of antistatic agents A and B (samples 1-2 and 1-4 respectively) described in Example 1 (Table 1) were evaluated by hydrocephalus and resistivide tests. surface after exposure to STERRAD * ™ * ™ oxidising gas plasma treatment. Each fabric was cut into four pieces of about 30 centimeters in the transverse direction and about 38 centimeters in the direction of the machine. Each piece was placed in the STERRAD camera ^^ in a different place, for example the upper front part (TF), the upper rear part (TB), the lower front part (LF), and the lower rear part (LB). The pieces were removed after the STERRAD1 ** ™ treatment and tested for the hydro head (two samples of each fabric) and the surface resistivity (five samples of each cloth) as described in Example 1. The data is summarized in Tables 5 and 6.

Table 5 Hydrohead data 4-2 B 5800 4350 3850 1080 2980 aIn Newtons per square meter Table 6 Surface Resistivity Data In order to better illustrate the effect of the location within the sterilization chamber and the differences between the two antistatic agents studied, the data in Tables 5 and 6 were drawn as line graphs, shown in Figures 2 and 3, respectively. Tables 5 and 6 and figures 2 and 3 suggest the following conclusions: Before Sterilization Fabric treated with antistatic agent A had a surface resistivity which was well below the limit of failure of 1014 ohms per square inch.

• Fabric treated with antistatic agent B had a surface resistivity which is slightly above the limit of failure.

Fabric treated with antistatic agent B has a higher hydro head value than the fabric treated with the antistatic agent A.

After Sterilization • Fabric treated with antistatic agent B had a lower surface resistivity than the fabric treated with antistatic agent A, regardless of the location of the fabric in the sterilization chamber.

• Fabric treated with antistatic agent B had higher hydroheat values than those treated with antistatic agent A, regardless of the location of the tel in the sterilization chamber.

The hydro head values for the fabric treated with the antistatic agent A were only about 15-20% of the hydro head count for the fabric which had not been sterilized.

• The hydro head values for the fabric treated with the antistatic agent B were typically greater than about 50 of the hydro head count for the fabric which had not been sterilized.

Apparently the anomalous results were associated with the lower front of the sterilization chamber for unknown reasons.

The procedure of Example 1 was repeated with antistatic agents and additional levels of antistatic agents on the fabric. The antistatic agents employed were as follows: (1) antistatic agent A of Example 1; (2) antistatic agent D, which was supplied as a solution of 50% by weight approximately of isobutyl dipotassium phosphate and potassium diisobutyl phosphate and approximately equimolar amounts (Polyfix "^^ N, Schill Seilacher GmbH &Co., from Boblingen, Germany); (3) antistatic agent E, which was supplied as a solution of about 50 by weight of the dipotassium salt of propylene glycol ester of phosphoric acid and the potassium salt of propylene glycol diester of phosphoric acid in quantity approximately equimolar (Quadrastat ^^ PPG-50, Manufacturer Chemical, Cleveland, Tennessee), and (4) Antistatic agent which was supplied as a solution of approximately 50% by weight of the dipotassium salt of a pentaerythritol ester of phosphoric acid and the potassium salt of a diester pentaerythritol d phosphoric acid in a molar ratio of about 1: (Quadrastat ^^ P4K, Manufacturers Chemical, Cleveland, Ten nessee.) Most, if not all, of the antistatic agents are known because they also include minor amounts (for example of up to about 20 mol%) of pyrophosphate, as well as small amounts of triester and phosphoric acid. It can be noted that pyrophosphate, an example of a polyphosphate chain, contains two phosphorus atoms linked by an oxygen bridge. Pyrophosphate typically also contains two ester groups; therefore, even though it is not an effective antistatic agent such as a diester of phosphoric acid, pyrophosphate is a diester which falls within the scope of the present invention. For a discussion of pyrophosphate phosphates, see F. Albert Cotton and Geoffrey Wilkinson, "Advanced Inorganic Chemistry: A Comprehensive Text," Quarter - Edition, by John Wiley & Sons, New York, 1980, pages 472 6.

Two levels of the antistatic agent were applied to the fabric: (1) 0.01% by weight, and (2) 0.08% by weight For a target level of 0.01% by weight of the antistatic agent on the cloth, the treatment solution was obtained by diluting the solution as supplied with hexanol and deionized water to give a concentration of antistatic agent in hexanol in the treatment solution d 0.017% by weight and 0.55% by weight, respectively. The second target level of 0.08% by weight was obtained in a similar manner, except that the final concentrations of the antistatic agent and hexanol were 0.133% by weight and 0.55 by weight, respectively. In each case, the work volume was 8 liters. Each antistatic agent was applied topically to the fabric as described in Example 1.

The antistatic properties of the treated fabrics were determined by the load dissipation or static decay test. Five duplicates of the treated fabric were measured and an average value was calculated. The test conforms to the specifications of the standard test INDA 40.2 92. This differs from the method 4046, Standard of Federal Test Methods No. 101C, in the following ways: (a) the sample size is about 9 x 15 centimeters, rather than d around 8 x 13 centimeters; (b) the samples were tested as received without aging; (c) the samples were conditioned and tested in an atmosphere maintained at a temperature of 23 ° C and a relative humidity of 50% but not placed in a desiccant chamber for 24 hours before the test; and (d) five samples, rather than three were tested for each sample. See also standard 99-1986 of the National Fire Prevention Association (NFPA). You may notice that the procedure of the National Fire Prevention Association is identical to the Federal Test Method, except that the National Fire Prevention Association specifies that before the test, the specimens must be conditioned for 2 hours or until it is reached. the equilibrium. The test used a calibrated static decay meter, such as the SD 406C or 406D model (Electro-Tech Systems Inc., of Glenside Pennsylvania). As in example 1, the effectiveness of the treated cloth as a barrier to liquids was determined by the hydro head test described above. The treated fabrics are summarized in Table 7. The hydro head and the antistatic data are summarized in Tables 8 and respectively.

Table 7 Summary of Treated Fabrics Table 8 Hydrohead data Table 9 Antistatic Data From Table 2 it is noted that the cloth which has been treated with an antistatic agent has a hydro head of 5.07 Newtons per square meter (Nm "2) Even with the aggregates under used in this example, it is seen from the Table 8 that the antistatic agent A causes a decrease in the hydro head and comparison to the hydro head of the untreated fabric At the 0.01% addition, the antistatic agent D appears to have caused an increase in the hydro head, compared to the treated fabric. At an aggregate of 0.08%, the decrease in the hydro head was lower than the decrease observed with the antistatic agent at both aggregate levels studied.The results of hydro head for the antistatic agents E and F were interesting in the sense that the materials did not sun appeared to increase the hydro head, but also the increase fu directly proportional to the aggregate level.The amount d increase of hydro head was significantly higher with the antistatic agent F than with the anties agent Tatic E.

Based on the data in Table 9, the antistatic properties of the antistatic agents A and were both similar and acceptable. In general, the properties of antistatic agents E and F were marginally acceptable at the aggregate levels studied. If the observed streams at the higher aggregate level were maintained at even higher levels of aggregates, antistatic agents and F would give good results at these higher levels.

Finally, none of the antistatic agents studied produced a bad odor with the sterilization of the cloth treated in an oxidizing gas plasma as described in Example 2.

Example 6 The procedure of Example 3 was repeated with antistatic agents A, D, E and F. A fifth antistatic agent, labeled G was also included. The antistatic agent G (TLF-8285, from DuPont Chemicals, of Wilmington, Delaware) was supplied as a 50% by weight solution of approximately dipotassium octyl phosphate and potassium dioctyl phosphate in approximately equimolar amounts. The results are summarized in Table 10.

Table 10 Summary of Surface Voltage Data The data in Table 10 indicates that all antistatic agents appear to lower the surface tension of water below approximately 72-4 x 10"3 Newtons per meter per water alone (see Table 4) .The antistatic agent was exceptional in This aspect Due to the effectiveness of material to lower surface tension, even low concentrations, the material was not included in the antistatic studies reported in the previous example.The effectiveness suggested the desirable in having no more than about 7 atoms of carbon in the ester portions of the β-carbon substituted mono- and di-alkyl phosphate usable in the present invention The antistatic agent D was more or less comparable to the antistatic agent A with respect to the decrease in surface tension values, but not The hydro head was lowered as much as the antistatic agent A (see Table 8), although the antistatic agents E and F seem to have a decreasing effect on the at surface tension, such an effect appeared to be independent of the concentration of the agent in the solution. This was particularly true for the antistatic agent E Even though the description has been described and detailed with respect to the specific incorporations thereof, it will be appreciated by those skilled in the art, upon achieving an understanding of the foregoing, that they can easily conceive alterations, variations and equivalents of this incorporations. Therefore, the scope of the present invention should be established as that of the appended claims any equivalents thereof.

Claims (22)

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

1. A method for preparing a non-woven cloth id sterilized, the method comprises: provide a nonwoven fabric; coating the non-woven fabric with from about 0.005 to about 3% by weight based on the fabric weight of an antistatic agent; Y exposing the coated nonwoven fabric to an oxidizing gas plasma; wherein the antistatic agent is adapted to be free of a bad odor after exposure of the non-woven fabric coated to the oxidizing gas plasma.

2. The method, as claimed in clause 1, characterized in that the antistatic agent is further adapted to provide a sterilized nonwoven fabric having a hydro head value as measured by method 551 of the Federal Test Method Standard No. 191A which is at least 50% of the hydro head value of the coated non-woven fabric prior to exposure to the oxidizing gas plasma.

3. The method, as claimed in clause 1, characterized in that the antistatic agent is further adapted to provide a sterilized nonwoven fabric having a surface resistivity in ohms which is lower than the surface resistivity in ohms of the coated woven fabric before exposure of the non-woven fabric coated to the oxidizing gas plasma.

4. The method, as claimed in clause 1, characterized in that the antistatic agent is an alkali metal or ammonium salt of a C3 alkyl mono- and di-phosphate in which the C3 alkyl moiety is a group alkyl containing three carbon atoms optionally substituted with hydroxy groups or a mixture of two or more of such salts.

5. The method, as claimed in clause 4, characterized in that the antistatic agent is an alkali metal or ammonium salt of propyl phosphate, dipropyl phosphate, isopropyl phosphate, diisopropyl phosphate, or a mixture d two or more of the above .

6. The method, as claimed in clause 5, characterized in that the salt is a potassium salt.

7. The method, as claimed in clause 1, characterized in that the antistatic agent is alkali metal or ammonium salt of a substituted carbon phosphate β carbon, a di (substituted alkyl β-carbon), phosphate or a mixture of two or more of the above in which the group of substituted alkyl of β-carbon contains from 4 to about 7 carbon atoms.

8. The method, as claimed in clause 7, characterized in that the antistatic agent is alkali metal or ammonium salt of isobutyl phosphate, diisobutyrate or a mixture thereof.

9. The method, as claimed in clause 81, characterized in that the salt is a potassium salt

10. The method, as claimed in clause 1, characterized in that the oxidizant gas plasma comprises a plasma of hydrogen peroxide gas.

11. The method, as claimed in clause 1, characterized in that the non-woven fabric is a melt blown fabric.

12. The method, as claimed in clause 11, characterized in that the fabric blown with fusion is a component of a laminate.

13. The method, as claimed in clause 12, characterized in that the meltblown fabric is between and joined to two fabrics bonded with yarn.

14. A fibrous sheet type material which comprises: a non-woven fabric impervious to water and permeable to gas coated with from about 0.005 to about 3% by weight, based on the weight of the fabric, of an antistatic agent; wherein the antistatic agent is adapted, after exposure of the water-impermeable non-woven fabric coated with an oxidizing gas plasma; to be free of a bad smell; Y to provide a non-woven fabric having a hydro head as measured by method 5514 of Federal Test Method Standard No. 191A after exposure to oxidizing gas plasma which is at least 50% of the value Hydrohead of the waterproof nonwoven fabric coated before exposure to the oxidizing gas plasma.

15. A barrier fabric comprising the fibrous sheet type material as claimed in clause 14.

16. A sterilization wrapper comprising the fibrous sheet type material as claimed in clause 14.

17. A surgical garment comprising fibrous sheet type material, as claimed in clause 14.

18. A package of medical procedure that includes: a fluid-permeable container having an exterior and an interior; one or more articles that are to be sterilized which are present inside the container; and one or more layers of sterilization wrap that surround the outside of the container in a sealing relationship wherein the sterilization wrapping includes a waterproof and gas permeable woven fabric coated with d from about 0.005 to about 3% by weight, based on the weight of the fabric, of an antistatic agent, wherein the agent antistatic is adapted, after the exposure of the waterproof non-woven fabric coated to an oxidising gauge plasma; to be free of a bad smell; Y to provide a non-woven fabric having a hydro head as measured by method 5514 of the Federal Test Method Standard No. 191A after exposure to the oxidizing gas plasma which is at least 50% of the Hydrohead value of the waterproof nonwoven fabric coated prior to exposure to the oxidizing gauge plasma.

19. The package of medical procedure, such and com is claimed in clause 18, characterized in that the packet is exposed to a plasma of oxidizing gas.

20 The package of the medical procedure that includes: a container impermeable to liquid having an interior and an exterior, in which at least one part of the container comprises a non-woven fabric impermeable to water permeable to gas; Y one or more articles that are to be sterilized which are present inside the container; wherein the non-woven fabric is coated with from about 0.005 to about 3% by weight, based on the weight of the fabric, of an antistatic agent, wherein the antistatic agent is adapted, after exposure of the cloth non-woven water-impervious coated with an oxidising gauge plasma; to be free of a bad smell; Y to provide a non-woven fabric having a hydro head as measured by method 5514 of the Federal Test Method Standard No. 191A after exposure to the oxidizing gas plasma which is at least 50% of the Hydrohead value of the waterproof nonwoven fabric coated prior to exposure to the oxidizing gauge plasma.

21. The package of medical procedure, such and com is claimed in clause 20, characterized in that the packet is exposed to a plasma of oxidizing gas.

22. The invention, as claimed and claimed there, < 3 60 R E S U M E N A method for preparing a non-woven cloth id sterilized, which method includes providing a cloth n • 5 woven; coating the non-woven fabric with from about 0.005 to about 3% by weight, based on the weight of fabric, of an antistatic agent; and exposing the coated non-woven fabric to a plasma of oxidizing gas. The antistatic agent is adapted to be free of odors after 10 exposure of the non-woven fabric coated to the oxidising gauge plasma. The antistatic agent may also be adapted to provide a sterilized non-woven fabric having a hydro head as measured by method 5514 of Standard Test Methods No. 191A which is of a non-woven fabric. Less than 50% of the hydro head value of the coated non-woven fabric before being exposed to the oxidising gas plasma. The antistatic agent may also be adapted to provide a sterilized nonwoven fabric having a surface resistivity in ohms which is lower than the 20 surface resistivity in ohms of the non-woven fabric coated before exposure of the non-woven fabric coated to the oxidising gas plasma. The antistatic agent can be an alkali metal or ammonium salt of either a C3 alkyl mono- or di-phosphate in which the C3 alkyl moiety is a Alkyl group containing 3 carbon atoms optionally substituted with hydroxy groups or a substituted alkyl phosphate v «61 β-carbon, a di (substituted β-carbon alkyl) phosphate or a mixture of two or more of the above. The invention also provides a fibrous sheet type material, such as a barrier fabric, a sterilization wrap, a surgical fascia and medical procedure packages.