Patent Description:
Fragrance delivery devices often include vapor permeable microporous membranes for uniform release of a fragrance, such as a fragrance oil, over time. The membrane includes a volatile material contact surface in contact with a fragrant oil in liquid form. Opposite the volatile material contact surface is a vapor release surface for releasing the fragrant oil in vapor form. The fragrance delivery device operates by the volatile liquid vaporizing and passing through the membrane. The vaporized oil is released to the atmosphere on the vapor release surface of the membrane.

A problem posed by known fragrance delivery devices including vapor permeable microporous membranes is preventing "sweating" of the fragrant oil under restricted air flow conditions. Sweating occurs when the volatile fragrant oil collects in liquid form on the vapor release surface of the membrane. This can lead to the fragrance delivery device leaking the fragrant oil onto the area surrounding the fragrance delivery device. For example, sweating can lead to liquid fragrant oil from the fragrance delivery device leaking onto household furniture or onto an interior surface of an automobile.

Another challenge posed by known fragrance delivery devices including vapor permeable microporous membranes is uniform fragrance delivery throughout the lifespan of the fragrance delivery device. If the rate at which the fragrant oil is released is too slow, the fragrance may not be detectable and may not freshen the surrounding air. Conversely, if the rate at which the fragrant oil is released is too fast, the fragrance may be overpowering and the lifespan of the fragrance delivery device may be reduced with the fragrant oil being consumed at a high rate.

Therefore, there is a need in the art for a fragrance delivery device that prevents sweating of liquid oil from the fragrance delivery device. Further, development of a fragrance delivery device that releases a uniform and appropriate amount of fragrance through the lifespan of the fragrance delivery device is also desirable.

<CIT> relates to breathable, hydrophobic microporous polyolefin membranes rendered oleophobic and resistant to contaminants by a fluorochemical treatment, which may contain an inorganic particulate filler material. It does not specify amounts of the particulate filler and the polyolefin component.

<CIT> relates to the delivery of fragrances and membranes with controlled volatile material transfer properties. The membranes may comprise a matrix of water-soluble thermoplastic organic polymer comprising polyolefin, a finely divided particulate filler, and a network of interconnecting pores throughout the microporous material. It does not foresee treating a surface of the membrane with a hydrophobic/oleophobic material and rather teaches coating the membrane surface(s) with hydrophilic coating compositions comprising poly(vinyl alcohol).

<CIT> relates to an apparatus for delivery of a volatile material such as a fragrance. For treating a microporous membrane, it employs aqueous poly(meth)acrylate dispersions, PU dispersions and silicon oil dispersions or combinations thereof.

The present invention is directed to a treated vapor permeable microporous membrane as defined in appended independent claim <NUM>.

The present invention is also directed to a method of preparing a treated vapor permeable microporous membrane as defined in appended independent claim <NUM>. Brief description of the drawings.

For purposes of the following detailed description, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. Moreover, other than in any operating examples, or where otherwise indicated, all numbers expressing, for example, quantities of ingredients used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

In this application, the use of the singular includes the plural and plural encompasses singular, unless specifically stated otherwise. In addition, in this application, the use of "or" means "and/or" unless specifically stated otherwise, even though "and/or" may be explicitly used in certain instances. Further, in this application, the use of "a" or "an" means "at least one" unless specifically stated otherwise. For example, "an" oil rating, "a" fluoropolymer, and the like refer to one or more of these items. Also, as used herein, the term "polymer" is meant to refer to prepolymers, oligomers, and both homopolymers and copolymers. The term "resin" is used interchangeably with "polymer.

As used herein, the transitional term "comprising" (and other comparable terms, e.g., "containing" and "including") is "open-ended" and is used in reference to compositions, methods, and respective component(s) thereof that are essential to the invention, yet open to the inclusion of unspecified matter. The term "consisting essentially of" refers to those component(s) required for a given embodiment and permits the presence of component(s) that do not materially affect the properties or functional characteristic(s) of that embodiment. The term "consisting of" refers to compositions and methods that are exclusive of any other component not recited in that description of the embodiment.

Referring to <FIG>, a treated vapor permeable microporous membrane <NUM> (hereinafter "treated membrane") includes a microporous membrane <NUM> having a first side <NUM> and a second side <NUM> opposite the first side <NUM>. The membrane includes a thermoplastic organic polymer including a polyolefin. The membrane defines a network of interconnecting pores communicating substantially throughout the membrane <NUM>. Finely divided, particulate filler is distributed throughout the membrane <NUM>. A first hydrophobic/oleophobic material <NUM> covers at least a portion of the first side <NUM>.

The membrane <NUM> includes a thermoplastic organic polymer. In some examples, the thermoplastic organic polymer may be a substantially water-insoluble thermoplastic organic polymer. Substantially water-insoluble means having <<NUM>/L solubility in pure water at <NUM>.

The types of polymers suitable for use in the membrane <NUM> are numerous. In general, any substantially water-insoluble thermoplastic organic polymer which can be extruded, calendered, pressed, or rolled into film, sheet, strip, or web may be used. The polymer may be a single polymer or it may be a mixture of polymers. The polymers may be homopolymers, copolymers, random copolymers, block copolymers, graft copolymers, atactic polymers, isotactic polymers, syndiotactic polymers, linear polymers, or branched polymers. When mixtures of polymers are used, the mixture may be homogeneous or it may comprise two or more polymeric phases.

According to the present invention the thermoplastic organic polymer includes one or more thermoplastic polyolefins. The polyolefins comprise at least <NUM> weight percent, such as at least <NUM> weight percent, at least <NUM> weight percent, at least least <NUM> weight percent, at least <NUM> weight percent, at least <NUM> weight percent, at least <NUM> weight percent, at least <NUM> weight percent, at least <NUM> weight percent, at least <NUM> weight percent, or at least <NUM> weight percent of the membrane <NUM>, based on the total weight of the membrane <NUM> including particulate filler. The polyolefins may comprise up to <NUM> weight percent, such as up to <NUM> weight percent, up to <NUM> weight percent, up to <NUM> weight percent, up to <NUM> weight percent, up to <NUM> weight percent, up to <NUM> weight percent, up to <NUM> weight percent, or up to <NUM> weight percent of the membrane <NUM>, based on the total weight of the membrane <NUM> including particulate filler. The polyolefin may comprise <NUM> to <NUM> weight percent of the membrane <NUM>, based on the total weight of the membrane <NUM> including particulate filler. Other examples of classes of further suitable substantially water-insoluble organic polymers may include poly(halo-substituted olefins), polyesters, polyamides, polyurethanes, polyureas, poly(vinyl halides), poly(vinylidene halides), polystyrenes, poly(vinyl esters), polycarbonates, polyethers, polysulfides, polyimides, polysilanes, polysiloxanes, polycaprolactones, polyacrylates, and polymethacrylates. Contemplated hybrid classes, from which the substantially water-insoluble thermoplastic organic polymers may be selected include, for example, thermoplastic poly(urethane-ureas), poly(ester-amides), poly(silane-siloxanes), and poly(ether-esters). Further examples of suitable substantially water-insoluble thermoplastic organic polymers may include thermoplastic high density polyethylene, low density polyethylene, ultrahigh molecular weight polyethylene, polypropylene (atactic, isotactic, or syndiotactic), poly(vinyl chloride), polytetrafluoroethylene, copolymers of ethylene and acrylic acid, copolymers of ethylene and methacrylic acid, poly(vinylidene chloride), copolymers of vinylidene chloride and vinyl acetate, copolymers of vinylidene chloride and vinyl chloride, copolymers of ethylene and propylene, copolymers of ethylene and butene, poly(vinyl acetate), polystyrene, poly(omega-aminoundecanoic acid), poly(hexamethylene adipamide), poly(epsilon-caprolactam), and poly(methyl methacrylate). The recitation of these classes and example of substantially water-insoluble thermoplastic organic polymers is not exhaustive, and are provided only for purposes of illustration.

Substantially water-insoluble thermoplastic organic polymers may in particular include, for example, poly(vinyl chloride), copolymers of vinyl chloride, or mixtures thereof. In an embodiment, the water-insoluble thermoplastic organic polymer includes an ultrahigh molecular weight polyolefin selected from: ultrahigh molecular weight polyolefin, e.g., essentially linear ultrahigh molecular weight polyolefin) having an intrinsic viscosity of at least <NUM> deciliters/gram; or ultrahigh molecular weight polypropylene, e.g., essentially linear ultrahigh molecular weight polypropylene) having an intrinsic viscosity of at least <NUM> deciliters/gram; or mixtures thereof. In a particular embodiment, the water-insoluble thermoplastic organic polymer includes ultrahigh molecular weight polyethylene, e.g., linear ultrahigh molecular weight polyethylene, having an intrinsic viscosity of at least <NUM> deciliters/gram.

Ultrahigh molecular weight polyethylene (UHMWPE) is not a thermoset polymer having an infinite molecular weight, but is technically classified as a thermoplastic. However, because the molecules are substantially very long chains, UHMWPE softens when heated but does not flow as a molten liquid in a normal thermoplastic manner. The very long chains and the peculiar properties they provide to UHMWPE may contribute in large measure to the desirable properties of the membrane <NUM> made using this polymer.

As indicated earlier, the intrinsic viscosity of the UHMWPE is at least about <NUM> deciliters/gram. Usually the intrinsic viscosity is at least about <NUM> deciliters/gram. Often the intrinsic viscosity is at least about <NUM> deciliters/gram. In many cases the intrinsic viscosity is at least about <NUM> deciliters/gram. Although there is no particular restriction on the upper limit of the intrinsic viscosity, the intrinsic viscosity is frequently in the range of from about <NUM> to about <NUM> deciliters/gram, e.g., in the range of from about <NUM> to about <NUM> deciliters/gram. In some cases the intrinsic viscosity of the UHMWPE is in the range of from about <NUM> to about <NUM> deciliters/gram, or from about <NUM> to about <NUM> deciliters/gram.

The nominal molecular weight of UHMWPE is empirically related to the intrinsic viscosity of the polymer according to the equation: <MAT> where M(UHMWPE) is the nominal molecular weight and [η] is the intrinsic viscosity of the UHMW polyethylene expressed in deciliters/gram.

As used herein, intrinsic viscosity is determined by extrapolating to zero concentration the reduced viscosities or the inherent viscosities of several dilute solutions of the UHMWPE where the solvent is freshly distilled decahydronaphthalene to which <NUM> percent by weight, <NUM>,<NUM>-di-tert-butyl-<NUM>-hydroxyhydrocinnamic acid, neopentanetetrayl ester [<NPL>] has been added. The reduced viscosities or the inherent viscosities of the UHMWPE are ascertained from relative viscosities obtained at <NUM> using an Ubbelohde No. <NUM> viscometer in accordance with the general procedures of ASTM D <NUM>-<NUM>, except that several dilute solutions of differing concentration are employed.

In one particular example, the matrix comprises a mixture of substantially linear ultrahigh molecular weight polyethylene having an intrinsic viscosity of at least <NUM> deciliters/gram, and lower molecular weight polyethylene (LMWPE) having an ASTM D <NUM>-<NUM> Condition E melt index of less than <NUM> grams/<NUM> minutes and an ASTM D <NUM>-<NUM> Condition F melt index of at least <NUM> gram/<NUM> minutes. The nominal molecular weight of LMWPE is lower than that of the UHMWPE. LMWPE is thermoplastic and many different types are known. One method of classification is by density, expressed in grams/cubic centimeter and rounded to the nearest thousandth, in accordance with ASTM D <NUM>-<NUM> (re-approved <NUM>), as summarized as follows:.

Any or all of these polyethylenes may be used as the LMWPE in the present invention. For some applications, HDPE, may be used because it ordinarily tends to be more linear than MDPE or LDPE. Processes for making the various LMWPE's are well known and well documented. They include the high pressure process, the Phillips Petroleum Company process, the Standard Oil Company (Indiana) process, and the Ziegler process.

The ASTM D <NUM>-<NUM> Condition E (that is, <NUM> and <NUM> kilogram load) melt index of the LMWPE is less than about <NUM> grams/<NUM> minutes. Often the Condition E melt index is less than about <NUM> grams/<NUM> minutes. Typically, the Condition E melt index is less than about <NUM> grams/<NUM> minutes.

The ASTM D <NUM>-<NUM> Condition F (that is, <NUM> and <NUM> kilogram load) melt index of the LMWPE is at least <NUM> gram/<NUM> minutes. In many cases the Condition F melt index is at least about <NUM> gram/<NUM> minutes. Typically, the Condition F melt index is at least about <NUM> gram/<NUM> minutes.

Sufficient UHMWPE and LMWPE should be present in the matrix to provide their properties to the membrane <NUM>. Other thermoplastic organic polymers may also be present in the matrix so long as their presence does not materially affect the properties of the membrane <NUM> in an adverse manner. One or more other thermoplastic polymers may be present in the matrix. The amount of the other thermoplastic polymer which may be present depends upon the nature of such polymer. Examples of thermoplastic organic polymers which may optionally be present include, but are not limited to, poly(tetrafluoroethylene), polypropylene, copolymers of ethylene and propylene, copolymers of ethylene and acrylic acid, and copolymers of ethylene and methacrylic acid. If desired, all or a portion of the carboxyl groups of carboxyl-containing copolymers may be neutralized with sodium, zinc, or the like.

In some examples the UHMWPE and the LMWPE together constitute at least about <NUM> percent by weight of the polymer of the matrix. In some examples, the UHMWPE and the LMWPE together constitute at least about <NUM> percent by weight of the polymer of the matrix. In some examples, the other thermoplastic organic polymers are substantially absent so that the UHMWPE and the LMWPE together constitute substantially <NUM> percent by weight of the polymer of the matrix. In some examples, the UHMWPE constitutes substantially all of the polymer of the matrix (e.g., LMWPE is not included in the formulation).

The UHMWPE may constitute at least one percent by weight of the polymer of the matrix. Where the UHMWPE and the LMWPE together constitute <NUM> percent by weight of the polymer of the matrix of the membrane <NUM>, the UHMWPE may constitute greater than or equal to <NUM> percent by weight of the polymer of the matrix, such as greater than or equal to <NUM> percent by weight, or greater than or equal to <NUM> percent by weight, or greater than or equal to <NUM> percent by weight, or greater than or equal to <NUM> percent by weight of the polymer of the matrix. Also, the UHMWPE may constitute less than or equal to <NUM> percent by weight of the polymer of the matrix, such as less than or equal to <NUM> percent by weight, or less than or equal to <NUM> percent by weight, or less than or equal to <NUM> percent by weight, or less than or equal to <NUM> percent by weight of the polymer of the matrix. The level of UHMWPE comprising the polymer of the matrix may range between any of these values inclusive of the recited values.

Likewise, where the UHMWPE and the LMWPE together constitute <NUM> percent by weight of the polymer of the matrix of the membrane <NUM>, the LMWPE may constitute greater than or equal to <NUM> percent by weight of the polymer of the matrix, such as greater than or equal to <NUM> percent by weight, or greater than or equal to <NUM> percent by weight, or greater than or equal to <NUM> percent by weight, or greater than or equal to <NUM> percent by weight, or greater than or equal to <NUM> percent by weight, or greater than or equal to <NUM> percent by weight, or greater than or equal to <NUM> percent by weight, or greater than or equal to <NUM> percent by weight, or greater than or equal to <NUM> percent by weight, or greater than or equal to <NUM> percent by weight, or greater than or equal to <NUM> percent by weight of the polymer of the matrix. Also, the LMWPE may constitute less than or equal to <NUM> percent by weight of the polymer of the matrix, such as less than or equal to <NUM> percent by weight, or less than or equal to <NUM> percent by weight, or less than or equal to <NUM> percent by weight, or less than or equal to <NUM> percent by weight, or less than or equal to <NUM> percent by weight of the polymer of the matrix. The level of the LMWPE may range between any of these values inclusive of the recited values.

It should be noted that for any of the previously described membranes <NUM> of the present invention, the LMWPE may comprise high density polyethylene.

The membrane <NUM> also includes finely divided, particulate filler distributed throughout, as later described. The membrane <NUM> may also include minor amounts of other materials. Minor amounts may be less than or equal to <NUM> percent by weight, based on total weight of the membrane <NUM>, particulate filler and other materials. The other materials used in processing, may be lubricants, processing plasticizers, organic extraction liquids, water, and the like. Further other materials introduced for particular purposes, such as thermal, ultraviolet and dimensional stability, may optionally be present in the membrane <NUM> in small amounts, e.g., less than or equal to <NUM> percent by weight, based on total weight of the membrane <NUM>, particulate filler, and other materials. Examples of such further materials include, but are not limited to, antioxidants, ultraviolet light absorbers, reinforcing fibers such as chopped glass fiber strand, and the like. The balance of the membrane <NUM>, exclusive of filler and any coating, printing ink, or impregnant applied for one or more special purposes is essentially the thermoplastic organic polymer.

As previously mentioned, the membrane <NUM> includes finely divided, particulate filler distributed through the membrane <NUM>. The particulate filler includes siliceous particles having particulate silica. The particulate filler may include an organic particulate material and/or an inorganic particulate material. The particulate filler may or may not be colored. For example, the particulate filler material may be a white or off-white particulate filler material, such as siliceous or clay particulate material.

The particulate filler are substantially water-insoluble filler particles. Substantially water-insoluble means having <<NUM>/L solubility in pure water at <NUM>.

The finely divided substantially water-insoluble filler particles constitute from <NUM> to <NUM> percent by weight of the membrane <NUM>, the filler particles, and other materials (excluding coating applied to the membrane <NUM>). For example, such filler particles may constitute from <NUM> percent to <NUM> percent by weight of the membrane <NUM>, the filler particles, and other materials (excluding coating applied to the membrane <NUM>), such as from <NUM> percent to <NUM> percent, or such as from <NUM> percent to <NUM> percent.

The finely divided, particulate filler may be in the form of ultimate particles, aggregates of ultimate particles, or a combination of both. At least about <NUM> percent by weight of the particulate filler used in preparing the membrane <NUM> may have gross particle sizes in the range of from <NUM> to about <NUM> micrometers, such as from <NUM> to <NUM> micrometers, as determined by the use of a laser diffraction particle size instrument, LS230 from Beckman Coulton, which is capable of measuring particle diameters as small as <NUM> micrometers. At least <NUM> percent by weight of the particulate filler may have a gross particle sizes in the range of from <NUM> to <NUM>, e.g., <NUM> to <NUM> micrometers. The sizes of the particulate filler agglomerates may be reduced during processing of the ingredients used to prepare the membrane <NUM>. Accordingly, the distribution of gross particle sizes in the membrane <NUM> may be smaller than in the raw filler itself.

Non-limiting examples of suitable organic and inorganic particulate filler that may be used in the membrane <NUM> of the present invention may include those described in <CIT> at column <NUM>, line <NUM> to column <NUM>, line <NUM>.

The particulate filler material includes siliceous particles. Non-limiting examples of siliceous fillers that may be used to prepare the microporous material include silica, mica, montmorillonite, kaolinite, nanoclays such as cloisite, which is available from Southern Clay Products (Gonzales, TX), talc, diatomaceous earth, vermiculite, natural and synthetic zeolites, calcium silicate, aluminum silicate, sodium aluminum silicate, aluminum polysilicate, alumina silica gels and glass particles. In addition to the siliceous fillers, other finely divided particulate substantially water-insoluble fillers optionally may also be employed. Non-limiting examples of such optional particulate fillers include carbon black, charcoal, graphite, titanium oxide, iron oxide, copper oxide, zinc oxide, antimony oxide, zirconia, magnesia, alumina, molybdenum disulfide, zinc sulfide, barium sulfate, strontium sulfate, calcium carbonate, and magnesium carbonate. Some of such optional fillers are color-producing fillers and, depending on the amount used, may add a hue or color to the microporous material. In a non-limiting embodiment, the siliceous filler may include silica and any of the aforementioned clays. Non-limiting examples of silicas include precipitated silica, silica gel, fumed silica, and combinations thereof.

Silica gel is generally produced commercially by acidifying an aqueous solution of a soluble metal silicate, e.g., sodium silicate, at low pH with acid. The acid employed is generally a strong mineral acid such as sulfuric acid or hydrochloric acid, although carbon dioxide can be used. Inasmuch as there is essentially no difference in density between the gel phase and the surrounding liquid phase while the viscosity is low, the gel phase does not settle out, that is to say, it does not precipitate. Consequently, silica gel may be described as a non-precipitated, coherent, rigid, three-dimensional network of contiguous particles of colloidal amorphous silica. The state of subdivision ranges from large, solid masses to submicroscopic particles, and the degree of hydration from almost anhydrous silica to soft gelatinous masses containing on the order of <NUM> parts of water per part of silica by weight.

Precipitated silica generally is produced commercially by combining an aqueous solution of a soluble metal silicate, ordinarily alkali metal silicate such as sodium silicate, and an acid so that colloidal particles of silica will grow in a weakly alkaline solution and be coagulated by the alkali metal ions of the resulting soluble alkali metal salt. Various acids may be used, including but not limited to mineral acids. Non-limiting examples of acids that may be used include hydrochloric acid and sulfuric acid, but carbon dioxide can also be used to produce precipitated silica. In the absence of a coagulant, silica is not precipitated from solution at any pH. In a non-limiting embodiment, the coagulant used to effect precipitation of silica may be the soluble alkali metal salt produced during formation of the colloidal silica particles, or it may be an added electrolyte, such as a soluble inorganic or organic salt, or it may be a combination of both.

Many different precipitated silicas can be employed as the siliceous filler used to prepare the microporous material. Precipitated silicas are well-known commercial materials, and processes for producing them are described in detail in many United States patents, including <CIT> and <CIT>. The average ultimate particle size (irrespective of whether or not the ultimate particles are agglomerated) of precipitated silica used to prepare the microporous material is generally less than <NUM> micrometer, e.g., less than <NUM> micrometer or less than <NUM> micrometer, as determined by transmission electron microscopy. Precipitated silicas are available in many grades and forms from PPG Industries, Inc. (Pittsburgh, PA). These silicas are sold under the Hi-Sil trademark.

For purposes of the present invention, the finely divided particulate siliceous filler can make up at least <NUM> percent by weight, e.g., at least <NUM> or at least <NUM> percent by weight, or at least <NUM> percent by weight of the particulate filler material. The siliceous filler may make up from <NUM> to <NUM> percent by weight, e.g., from <NUM> to <NUM> percent by weight, of the particulate filler, or the siliceous filler may make up substantially all (over <NUM> percent by weight) of the particulate filler.

The particulate filler, e.g., the siliceous filler, typically has a high surface area, which allows the filler to carry much of the processing plasticizer composition used to produce the microporous material of the present invention. High surface area fillers are materials of very small particle size, materials that have a high degree of porosity, or materials that exhibit both of such properties. The surface area of the particulate filler, e.g., the siliceous filler particles, can range from <NUM> to <NUM> square meters per gram, e.g., from <NUM> to <NUM> square meters per gram, or from <NUM> to <NUM> square meters per gram, as determined by the Brunauer, Emmett, Teller (BET) method according to ASTM D <NUM>-<NUM>. The BET surface area is determined by fitting five relative pressure points from a nitrogen sorption isotherm measurement made using a Micromeritics TriStar <NUM>™ instrument. A FlowPrep-<NUM>™ station can be used to provide heat and continuous gas flow during sample preparation. Prior to nitrogen sorption, silica samples are dried by heating to <NUM> in flowing nitrogen (PS) for <NUM> hour. The surface area of any non-siliceous filler particles used may also be within one of these ranges. The filler particles are substantially water-insoluble and may also be substantially insoluble in any organic processing liquid used to prepare the microporous material. Substantially water-insoluble means having <<NUM>/L solubility in pure water at <NUM>. Substantially insoluble in an organic processing liquid means having <<NUM>/L solubility in the organic processing liquid. This may facilitate retention of the particulate filler within the microporous material.

The membrane <NUM> also includes a network of interconnecting pores, which communicate substantially throughout the membrane <NUM>. On a coating-free, printing ink free and impregnant-free basis, pores typically constitute from <NUM> to <NUM> percent by volume, based on the total volume of the membrane <NUM>, when made by the processes as further described herein. The pores may constitute from <NUM> to <NUM> percent by volume of the membrane <NUM>, based on the total volume of the microporous material. As used herein, the porosity (also known as void volume) of the membrane <NUM>, expressed as percent by volume, is determined according to the following equation: <MAT> where, d<NUM> is the density of the sample, which is determined from the sample weight and the sample volume as ascertained from measurements of the sample dimensions; and d<NUM> is the density of the solid portion of the sample, which is determined from the sample weight and the volume of the solid portion of the sample. The volume of the solid portion of the microporous material is determined using a Quantachrome stereopycnometer (Quantachrome Instruments (Boynton Beach, FL)) in accordance with the operating manual accompanying the instrument.

The volume average diameter of the pores of the membrane <NUM> is determined by mercury porosimetry using an Autoscan mercury porosimeter (Quantachrome Instruments (Boynton Beach, FL)) in accordance with the operating manual accompanying the instrument. The volume average pore radius for a single scan is automatically determined by the porosimeter. In operating the porosimeter, a scan is made in the high pressure range (from <NUM> kilopascals absolute to <NUM> megapascals absolute). If <NUM> percent or less of the total intruded volume occurs at the low end (from <NUM> to <NUM> kilopascals absolute) of the high pressure range, the volume average pore diameter is taken as twice the volume average pore radius determined by the porosimeter. Otherwise, an additional scan is made in the low pressure range (from <NUM> to <NUM> kilopascals absolute) and the volume average pore diameter is calculated according to the equation: <MAT> where, d is the volume average pore diameter; v<NUM> is the total volume of mercury intruded in the high pressure range; v<NUM> is the total volume of mercury intruded in the low pressure range; r<NUM> is the volume average pore radius determined from the high pressure scan; r<NUM> is the volume average pore radius determined from the low pressure scan; w<NUM> is the weight of the sample subjected to the high pressure scan; and w<NUM> is the weight of the sample subjected to the low pressure scan.

Generally on a coating-free, printing ink-free and impregnant-free basis, the volume average diameter of the pores (mean pore size) of the membrane <NUM> is up to <NUM> micrometers. The average diameter of the pores may be at least <NUM> micrometers, such as at least <NUM> micrometers, or at least <NUM> micrometers. The volume average diameter of the pores, on this basis, may range between any of these values, inclusive of the recited values. For example, the volume average diameter of the pores of the membrane <NUM> may range from <NUM> to <NUM> micrometers, or from <NUM> to <NUM> micrometers, or from <NUM> to <NUM> micrometers, in each case inclusive of the recited values.

In the course of determining the volume average pore diameter by means of the above described procedure, the maximum pore radius detected may also be determined. This is taken from the low pressure range scan, if run; otherwise it is taken from the high pressure range scan. The maximum pore diameter of the microporous material is typically twice the maximum pore radius.

Coating, printing and impregnation processes may result in filling at least some of the pores of the membrane <NUM>. In addition, such processes may also irreversibly compress the membrane <NUM>. Accordingly, the parameters with respect to porosity, volume average diameter of the pores, and maximum pore diameter are determined for the membrane <NUM> prior to application of one or more of these processes.

The membrane <NUM>, including the finely divided, particulate filler and/or other materials (excluding coating applied to the membrane <NUM>) may have a density between <NUM>/cm<NUM> and <NUM>/cm<NUM>. The density can range between any of the above-stated values, inclusive of the recited values. As used herein and in the claims, the density of the membrane <NUM> is determined by measuring the weight and volume of a sample of the microporous material.

The porosity of the membrane <NUM> may be measured in terms of the rate of air flow through a sample, herein measured and reported as Gurley porosity. The Gurley porosity of the membrane <NUM>, including the finely divided, particulate filler and/or other materials (excluding coating applied to the membrane <NUM>) may be greater than <NUM> seconds, such as greater than <NUM> seconds, greater than <NUM> seconds, greater than <NUM> seconds, greater than <NUM> seconds, or greater than <NUM> seconds. Gurley porosity is determined using a Gurley densometer, model <NUM>, manufactured by GPI Gurley Precision Instruments of (Troy, NY) The Gurley porosity reported was a measure of the rate of air flow through a sample or it's resistance to an air flow through the sample. The unit of measure is a "Gurley second" and represents the time in seconds to pass <NUM> cc of air through a <NUM> inch square (<NUM>×<NUM>-<NUM> m<NUM>) area using a pressure differential of <NUM> inches of water (<NUM>×<NUM><NUM> Pa). Lower values equate to less air flow resistance (more air is allowed to pass freely). The measurements were completed using the procedure listed in the manual, MODEL <NUM> Automatic Densometer and Smoothness Tester Instruction Manual. TAPPI method T <NUM> om-<NUM>-Air Resistance of Paper may also be referenced for the basic principles of the measurement.

Numerous art-recognized processes may be used to produce the membrane <NUM>. For example, the membrane <NUM> may be prepared by mixing together filler particles, thermoplastic organic polymer powder, processing plasticizer and minor amounts of lubricant and antioxidant, until a substantially uniform mixture is obtained. The weight ratio of particulate filler to polymer powder employed in forming the mixture may be essentially the same as that of the membrane <NUM> to be produced. The mixture, together with additional processing plasticizer, may be introduced into the heated barrel of a screw extruder. Attached to the terminal end of the extruder may be a sheeting die. A continuous sheet formed by the die may be forwarded without drawing to a pair of heated calender rolls acting cooperatively to form a continuous sheet of lesser thickness than the continuous sheet exiting from the die. The level of processing plasticizer present in the continuous sheet at this point in the process may vary and may affect the density of the membrane. For example, the level of processing plasticizer present in the continuous sheet, prior to extraction as described herein below, may be greater than or equal to <NUM> percent by weight of the continuous sheet, such as greater than or equal to <NUM> percent by weight, or greater than or equal to <NUM> percent prior to extraction. Also, the amount of processing plasticizer present in the continuous sheet prior to extraction may be less than or equal to <NUM> percent by weight of the continuous sheet, such as less than or equal to <NUM> percent, or less than or equal to <NUM> percent, or less than or equal to <NUM> percent prior to extraction. The level of processing plasticizer present in the continuous sheet at this point in the process, prior to extraction, may range between any of these values inclusive of the recited values. In one embodiment the amount of processing plasticizer may vary from <NUM> to <NUM> weight percent, and in another embodiment be less than <NUM> weight percent.

The continuous sheet from the calender may then passed to a first extraction zone where the processing plasticizer is substantially removed by extraction with an organic liquid, which is a good solvent for the processing plasticizer, a poor solvent for the organic polymer, and more volatile than the processing plasticizer. Both the processing plasticizer and the organic extraction liquid may be substantially immiscible with water. The continuous sheet may then pass to a second extraction zone where residual organic extraction liquid is substantially removed by steam and/or water. The continuous sheet may then pass through a forced air dryer for substantial removal of residual water and remaining residual organic extraction liquid. From the dryer the continuous sheet, which is the membrane <NUM>, may be passed to a take-up roll.

The processing plasticizer may be a liquid at room temperature and may be a processing oil such as paraffinic oil, naphthenic oil, or aromatic oil. Suitable processing oils include those meeting the requirements of ASTM D <NUM>-<NUM>. Types <NUM> and <NUM>. Processing oils having a pour point of less than <NUM> according to ASTM D <NUM>-<NUM> (re-approved <NUM>) may be used to produce the membrane <NUM>. Processing plasticizers useful in preparing the membrane <NUM> are discussed in further detail in <CIT> at column <NUM>, lines <NUM> through <NUM>.

The processing plasticizer composition used to prepare the membrane <NUM> may have little solvating effect on the polyolefin of the membrane <NUM> at <NUM>, and only a moderate solvating effect at elevated temperatures on the order of <NUM>. The processing plasticizer composition may be a liquid at room temperature. Non-limiting examples of processing oils that may be used may include SHELLFLEX® <NUM> oil, SHELLFLEX® <NUM> oil (Shell Oil Co. (Houston, TX)), which are solvent refined and hydrotreated oils derived from naphthenic crude oils, ARCOprimeX® <NUM> oil (Atlantic Richfield Co. (La Palma, CA)) and KAYDOL® oil (Witco Corp. (Greenwich, CT)), which are white mineral oils. Other non-limiting examples of processing plasticizers may include phthalate ester plasticizers, such as dibutyl phthalate, bis(<NUM>-ethylhexyl) phthalate, diisodecyl phthalate, dicyclohexyl phthalate, butyl benzyl phthalate, and ditridecyl phthalate. Mixtures of any of the foregoing processing plasticizers may be used to prepare membrane <NUM>.

There are many organic extraction liquids that may be used to prepare the membrane <NUM>. Examples of suitable organic extraction liquids include those described in <CIT> at column <NUM>, lines <NUM> through <NUM>.

The extraction fluid composition may include halogenated hydrocarbons, such as chlorinated hydrocarbons and/or fluorinated hydrocarbons. In particular, the extraction fluid composition may include halogenated hydrocarbon(s) and have a calculated solubility parameter coulomb term (δclb) ranging from <NUM> to <NUM> (Jcm<NUM>)<NUM>/<NUM>. Non-limiting examples of halogenated hydrocarbon(s) suitable as the extraction fluid composition for use in producing the membrane <NUM> may include one or more azeotropes of halogenated hydrocarbons selected from trans-<NUM>,<NUM>-dichloroethylene, <NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>-decafluoropentane, and/or <NUM>,<NUM>,<NUM>,<NUM>,<NUM>-pentafluorobutane. Such materials are available commercially as VERTREL MCA (a binary azeotrope of <NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>-dihydrodecafluoropentane and trans-<NUM>,<NUM>-dichloroethylene: <NUM>%/<NUM>%), and VERTREL CCA (a ternary azeotrope of <NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>-dihydrodecafluorpentane, <NUM>,<NUM>,<NUM>,<NUM>,<NUM>-pentafluorbutane, and trans-<NUM>,<NUM>-dichloroethylene: <NUM>%/<NUM>%/<NUM>%), both available from MicroCare Corporation (New Britain, CT).

The residual processing plasticizer content of the membrane <NUM> may be less than <NUM> percent by weight, based on the total weight of the membrane <NUM>, and this amount may be further reduced by additional extractions using the same or a different organic extraction liquid. The residual processing plasticizer content may be less than <NUM> percent by weight, based on the total weight of the membrane <NUM>, and this amount may be further reduced by additional extractions.

The membrane <NUM> may also be produced according to the general principles and procedures of <CIT>; <CIT>; and/or<CIT>. These principles and procedures are particularly applicable where the polymer of the matrix is or is predominately poly(vinyl chloride) or a copolymer containing a large proportion of polymerized vinyl chloride.

Membranes <NUM> produced by the above-described processes optionally may be stretched. Stretching of the membrane <NUM> may result in both an increase in the void volume of the material, and the formation of regions of increased or enhanced molecular orientation. As is known in the art, many of the physical properties of molecularly oriented thermoplastic organic polymer, including tensile strength, tensile modulus, Young's modulus, and others, differ, e.g., considerably, from those of the corresponding thermoplastic organic polymer having little or no molecular orientation. Stretching may be accomplished after substantial removal of the processing plasticizer as described above.

Various types of stretching apparatus and processes are well known to those of ordinary skill in the art, and may be used to accomplish stretching of the membrane <NUM>. Stretching of the membrane <NUM> is described in further detail in <CIT> at column <NUM>, line <NUM> through column <NUM>, line <NUM>.

Subsequent materials are applied to the membrane <NUM> to form the treated membrane <NUM>. A hydrophobic/oleophobic material(s), a hydrophilic coating layer(s), or some combination thereof is applied to the membrane <NUM>.

Referring to <FIG>, the first hydrophobic/oleophobic material <NUM> is applied to the membrane <NUM>. The first hydrophobic/oleophobic material <NUM> is applied to the first side <NUM> of the membrane <NUM> (as in <FIG>).

The first hydrophobic/oleophobic material <NUM> may be hydrophobic. Hydrophobic means that the side (such as the first side <NUM>) of the membrane <NUM> over which the first hydrophobic/oleophobic material <NUM> is applied demonstrates a water contact angle of at least <NUM>° using the Kruss Drop Shape Analysis. The side of the membrane <NUM> over which the first hydrophobic/oleophobic material <NUM> is applied may demonstrate a water contact angle of at least <NUM>°, such as at least <NUM>°, at least <NUM>°, at least <NUM>°, at least <NUM>°, at least <NUM>°, at least <NUM>°, at least <NUM>°, or at least <NUM>°.

The first hydrophobic/oleophobic material <NUM> may be oleophobic. Oleophobic means that the side of the membrane <NUM> over which the first hydrophobic/oleophobic material <NUM> is applied demonstrates an oil rating of at least <NUM>, such as at least <NUM> or at least <NUM>, based on AATCC test method <NUM>-<NUM>.

The first hydrophobic/oleophobic material <NUM> may be hydrophobic and oleophobic.

In some examples, the first hydrophobic/oleophobic material <NUM> may form a coating over the membrane <NUM>. In other examples, the first hydrophobic/oleophobic material <NUM> may not form a coating over the membrane <NUM> but may instead be a surface treatment to the membrane <NUM>. Surface treatment, in this situation, means that the first hydrophobic/oleophobic material <NUM> chemically reacts with the membrane <NUM> (such as the siliceous filler dispersed throughout the membrane <NUM>) so as to form a hydrophobic/oleophobic region of the membrane <NUM>.

The first hydrophobic/oleophobic material <NUM> includes at least one fluoro-alkyl group. It may include a polymer including at least one fluoro-alkyl group. The first hydrophobic/oleophobic material <NUM> may be a fluoro-alkyl group containing co-polymer. The first hydrophobic/oleophobic material <NUM> may be a polyacrylate co-polymer having a fluorinated polymer. In one non-limiting example, the first hydrophobic/oleophobic material <NUM> may include products sold under the Unidyne tradename, available from Daikin Industries, Ltd. (Osaka, Japan). The first hydrophobic/oleophobic material <NUM> may include any of the fluoro-alkyl group containing polymers or co-polymers described in <CIT> or <CIT>. The first hydrophobic/oleophobic material <NUM> may include a polymer including some fluorination in the side chains or ends of the polymer, with the backbone of the polymer being substantially free of fluorine groups (distinguishable from perfluorinated polymers).

The first hydrophobic/oleophobic material <NUM> may include an alkoxysilane compound having at least one fluoro-alkyl group. The first hydrophobic/oleophobic material <NUM> including the alkoxysilane compound having at least one fluoro-alkyl group may interact with the membrane <NUM> (such as with the siliceous filler) through a condensation reaction with filler and may form a hydrophobic/oleophobic region of the membrane <NUM>. Non-limiting examples of the alkoxysilane compound having at least one fluoro-alkyl group are (tridecafluoro-<NUM>,<NUM>,<NUM>,<NUM>-tetrahydrooctyl)triethoxysilane (see Formula I below) or (tridecafluoro-<NUM>,<NUM>,<NUM>,<NUM>-tetrahydrooctyl)trimethoxysilane.

As shown in <FIG>, the first hydrophobic/oleophobic material <NUM> may be applied over the first side <NUM> of the membrane <NUM> without any material applied over the second side <NUM>. Alternatively, the first hydrophobic/oleophobic material <NUM> may be applied over the first side <NUM> of the membrane <NUM> with material also being applied on the second side <NUM> (see <FIG>). Additional material may be applied over top of or underneath the first hydrophobic/oleophobic material <NUM>. In some examples, the first hydrophobic/oleophobic material <NUM> is in direct contact with the first side <NUM> and/or the second side <NUM> of the membrane <NUM>. The first hydrophobic/oleophobic material <NUM> may be applied to the first side <NUM> and/or the second side <NUM> of the membrane <NUM> using any suitable method such as spray application, curtain coating, dip coating, slot die coating, screen printing, and/or drawn-down coating, e.g., by means of a doctor blade or draw-down bar, techniques. In one non-limiting embodiment, the first hydrophobic/oleophobic material <NUM> is applied to the first side <NUM> of the membrane <NUM> using a draw-down method such that only the first side <NUM> of the membrane <NUM> is coated with first hydrophobic/oleophobic material <NUM> and not the second side <NUM>.

Referring to <FIG>, the membrane may be coated with a second hydrophobic/oleophobic material <NUM>. The a second hydrophobic/oleophobic material <NUM> may be applied to the first side <NUM> of the membrane <NUM> and/or the second side <NUM> of the membrane <NUM> (as shown in <FIG>).

The second hydrophobic/oleophobic material <NUM> may be hydrophobic. The side (such as the first side <NUM> or the second side <NUM>) of the membrane <NUM> over which the second hydrophobic/oleophobic material <NUM> is applied may demonstrate a water contact angle of at least <NUM>°, such as at least <NUM>°, at least <NUM>°, at least <NUM>°, at least <NUM>°, at least <NUM>°, at least <NUM>°, at least <NUM>°, or at least <NUM>°.

The second hydrophobic/oleophobic material <NUM> may be chosen from any of the materials of the previously described first hydrophobic/oleophobic material <NUM>.

As shown in <FIG>, the second hydrophobic/oleophobic material <NUM> may be applied over the second side <NUM> of the membrane <NUM> opposite the first side <NUM>, which has the first hydrophobic/oleophobic material <NUM> applied thereon. The second hydrophobic/oleophobic material <NUM> on the second side <NUM> may be the same hydrophobic/oleophobic material or a different hydrophobic/oleophobic material from the first hydrophobic/oleophobic material <NUM> on the first side <NUM>. Additional materials may be applied over top of or underneath the second hydrophobic/oleophobic material <NUM>. In some examples, the second hydrophobic/oleophobic material <NUM> is in direct contact with the first side <NUM> and/or the second side <NUM> of the membrane <NUM>.

The second hydrophobic/oleophobic material <NUM> may be applied to the first side <NUM> and/or the second side <NUM> of the membrane <NUM> using any suitable method such as spray application, curtain coating, dip coating, slot die coating, screen printing, and/or drawn-down coating, e.g., by means of a doctor blade or draw-down bar, techniques. In one non-limiting embodiment, the second hydrophobic/oleophobic material <NUM> is applied to the second side <NUM> of the membrane <NUM> using a draw-down method such that only the second side <NUM> of the membrane <NUM> is coated with second hydrophobic/oleophobic material <NUM> and not the first side <NUM>.

Referring to <FIG>, the membrane <NUM> is coated with at least one hydrophilic coating <NUM>. The hydrophilic coating <NUM> is applied to the second side <NUM> of the membrane <NUM> (as shown in <FIG>).

The hydrophilic coating <NUM> is hydrophilic. Hydrophilic means that the side of the membrane <NUM> over which the hydrophilic coating <NUM> is applied demonstrates a water contact angle of less than <NUM>° using the Kruss Drop Shape Analysis. The side of the membrane <NUM> over which the hydrophilic coating <NUM> is applied may demonstrate a water contact angle of less than <NUM>°, such as less than <NUM>°, less than <NUM>°, less than <NUM>°, less than <NUM>°, less than <NUM>°, less than <NUM>°, less than <NUM>°, or less than <NUM>°.

In some non-limiting embodiments, the hydrophilic coating <NUM> may include one or more of a polyoxazoline, triblock copolymers based on poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol), polyamide, oxidized polyethylene or its derivatives, polyethyleneoxide, polyvinylpyrrolidone, poly(meth)acrylic acid, polyethylene glycol or its derivatives, polypropylene oxide or its derivatives, a copolymer of poly(ethylene glycol) and polyethyleneoxide, polyvinyl alcohol, cellulose or its derivatives, collagen, polypeptides, guar, pectin, polyimide, poly(meth)acrylamide, polysaccharides, zwitterionic polymers, polyampholytes, and polyethylenimine.

As shown in <FIG>, the hydrophilic coating <NUM> is applied over the second side <NUM> of the membrane <NUM> opposite the first side <NUM>, which has the first hydrophobic/oleophobic material <NUM> applied thereover. Additional materials may be applied over top of or underneath the hydrophilic coating <NUM>. In some examples, the hydrophilic coating <NUM> is in direct contact with the second side <NUM> of the membrane <NUM>.

The hydrophilic coating <NUM> may be applied to the second side <NUM> of the membrane <NUM> using any suitable method such as spray application, curtain coating, dip coating, slot die coating, screen printing, and/or drawn-down coating, e.g., by means of a doctor blade or draw-down bar, techniques. In some examples, the hydrophilic coating <NUM> is applied to the second side <NUM> of the membrane <NUM> using a draw-down method such that only the second side <NUM> of the membrane <NUM> is coated with hydrophilic coating <NUM> and not the first side <NUM>.

In some examples, the membrane <NUM> may be pre-treated (before any other material is applied to the membrane <NUM>, such as the first hydrophobic/oleophobic material <NUM>, the second hydrophobic/oleophobic material <NUM>, or other hydrophilic coating <NUM>). The pre-treatment may be applied as a coating to the membrane <NUM>, and the pre-treatment may be a hydrophilic coating, as previously described. The pre-treatment may improve uniformity of the subsequently applied material(s), such as the hydrophobic/oleophobic materials or other hydrophilic coating(s).

The hydrophilic pre-treatment may be applied to the membrane <NUM> using any suitable method. In one example, the membrane <NUM> is dipped into a bath including the hydrophilic pre-treatment. The hydrophilic pre-treatment may be applied using other art-related methods, such as spray application, curtain coating, slot die coating, screen printing, and/or drawn-down coating, e.g., by means of a doctor blade or draw-down bar, techniques. The hydrophilic pre-treatment may be applied to the first side <NUM>, the second side <NUM>, or the entire membrane <NUM>. After the hydrophilic pre-treatment is applied, the pre-treated membrane <NUM> may be dried prior to any application of subsequent materials.

The membrane <NUM> may allow a volatile material to travel therethrough. The volatile material may be in a reservoir on the first side <NUM> of the membrane <NUM> such that the first side <NUM> is a volatile material contact surface <NUM>. The second side <NUM> may be a vapor release surface <NUM> not in contact with the volatile material in the reservoir but is the side from which the volatile material is released to the environment in a gaseous or vapor form.

Volatile material may be any material that is capable of conversion to a gaseous or vapor form, i.e., capable of vaporizing, at ambient room temperature and pressure, and in the absence of imparted additional or supplementary energy, e.g., in the form of heat and/or agitation. The volatile material may comprise an organic volatile material, which may include those volatile materials comprising a solvent-based material, or those which are dispersed in a solvent-based material. The volatile material may be in a liquid form and/or in a solid form, and may be naturally occurring or synthetically formed. When in a solid form, the volatile material may sublime from the solid form to the vapor form without passing thru an intermediate liquid form. The volatile material may optionally be combined or formulated with nonvolatile materials, such as a carrier, e.g., water and/or nonvolatile solvents. In the case of a solid volatile material, the nonvolatile carrier may be in the form of a porous material, e.g., a porous inorganic material, in which the solid volatile material is held. Also, the solid volatile material may be in the form of a semi-solid gel.

The volatile material may be a fragrance material, such as a naturally occurring or synthetic perfume oil. Examples of perfume oils from which the liquid volatile material may be selected include, but are not limited to, oil of bergamot, bitter orange, lemon, mandarin, caraway, cedar leaf, clove leaf, cedar wood, geranium, lavender, orange, origanum, petitgrain, white cedar, patchouli, neroili, rose absolute, and combinations thereof. Examples of solid fragrance materials from which the volatile material may be selected include, but are not limited to, vanillin, ethyl vanillin, coumarin, tonalid, calone, heliotropene, musk xylol, cedrol, musk ketone benzophenone, raspberry ketone, methyl naphthyl ketone beta, phenyl ethyl salicylate, veltol, maltol, maple lactone, proeugenol acetate, evemyl, and combinations thereof.

When volatile material is transferred from the volatile material contact surface <NUM> to the vapor release surface <NUM> of the membrane <NUM>, it is believed that the volatile material is in a form selected from liquid, vapor and a combination thereof. In addition, it is believed that the volatile material, at least in part, moves through the network of interconnecting pores that communicate substantially throughout the membrane <NUM>. The transfer of volatile material may occur at temperatures of from <NUM> to <NUM>, e.g., from <NUM> or <NUM> to <NUM> or <NUM> and at ambient atmospheric pressure.

The volatile material transfer rate of the membrane <NUM> may be determined in accordance with the following description. A test reservoir, having an interior volume sufficient to contain <NUM> milliliters of a model volatile material, such as benzyl acetate, dipropyleneglycol, methyl ether acetate, limonene, or other similar material (benzyl acetate will be used herein), was fabricated from a clear thermoplastic polymer. The interior dimensions of the reservoir was defined by a circular diameter at the edge of the open face of approximately <NUM> centimeters and a depth of no greater than <NUM> centimeter. The open face was used to determine the volatile material transfer rate. With the test reservoir lying flat (with the open face facing upward), about <NUM> milliliters of benzyl acetate was introduced into the test reservoir. With benzyl acetate introduced into the test reservoir, a sheet of microporous material having a thickness of from <NUM> to <NUM> mils was placed over the open face/side of the test reservoir, such that <NUM><NUM> of the volatile material contact surface of the microporous sheet was exposed to the interior of the reservoir. The test reservoir was weighed to obtain an initial weight of the entire charged assembly.

The volatile material transfer rate may be measured using non-restricted flow conditions. For the non-restricted flow conditions, the test reservoir, containing benzyl acetate and enclosed with the sheet of microporous material, was then placed, standing upright, in a laboratory chemical fume hood having approximate dimensions of <NUM> feet [<NUM> meters](height)×<NUM> feet [<NUM> meters](width)×<NUM> feet [<NUM> meters](depth). With the test reservoir standing upright, benzyl acetate was in direct contact with at least a portion of the volatile material contact surface of the microporous sheet. The glass doors of the fume hood were pulled down, and the air flow through the hood was adjusted so as to have eight (<NUM>) turns (or turnovers) of hood volume per hour. Unless otherwise indicated, the temperature in the hood was maintained at <NUM> ± <NUM>. The humidity within in the fume hood was ambient. The test reservoirs were regularly weighed in the hood. The calculated weight loss of benzyl acetate, in combination with the elapsed time and surface area of the microporous sheet exposed to the interior of the test reservoir, were used to determine the volatile transfer rate of the microporous sheet, in units of mg/(hour*cm<NUM>).

The volatile material transfer rate may be measured using restricted flow conditions. For the restricted flow conditions the test reservoir containing benzyl acetate and enclosed with the sheet of microporous material, was then placed in a HDPE enclosed box, having approximate dimensions of <NUM> inches [<NUM> meters] (height)× <NUM> inches [<NUM> meters] (width)× <NUM> inches [<NUM> meters] (depth). Enclosing the container was an <NUM> inch [<NUM> meters]×<NUM> inch [<NUM> meters] cardboard sheet, wrapped with duct tape. The calculated weight loss of benzyl acetate, in combination with the elapsed time and surface area of the microporous sheet exposed to the interior of the test reservoir, were used to determine the volatile transfer rate of the microporous sheet, in units of mg/(hour*cm<NUM>).

The volatile material transfer rate of the membrane <NUM> (using benzyl acetate as the model volatile material) according to the present invention under non-restricted flow conditions may be less than or equal to <NUM>/(hour*cm<NUM>), or less than or equal to <NUM>/(hour*cm<NUM>), or less than or equal to <NUM>/(hour*cm<NUM>), or less than or equal to <NUM>/(hour*cm<NUM>). The volatile material transfer rate of the membrane <NUM> may be equal to or greater than <NUM>/(hour*cm<NUM>), or equal to or greater than <NUM>/(hour*cm<NUM>), or equal to or greater than <NUM>/(hour*cm<NUM>), or equal to or greater than <NUM>/(hour*cm<NUM>). The volatile material transfer rate of the membrane <NUM> may range between any combination of these upper and lower values. For example, the volatile material transfer rate of the membrane <NUM> may be from <NUM> to <NUM>/(hour*cm<NUM>), or from <NUM> to <NUM>/(hour*cm<NUM>), or from <NUM> to <NUM>/(hour*cm<NUM>), in each case inclusive of the recited values.

The volatile material transfer rate of the membrane <NUM> (using benzyl acetate as the model volatile material) according to the present invention under restricted flow conditions may be less than or equal to <NUM>/(hour*cm<NUM>), or less than or equal to <NUM>/(hour*cm<NUM>), or less than or equal to <NUM>/(hour*cm<NUM>), or less than or equal to <NUM>/(hour*cm<NUM>). The volatile material transfer rate of the membrane <NUM> may be equal to or greater than <NUM>/(hour*cm<NUM>), or equal to or greater than <NUM>/(hour*cm<NUM>), or equal to or greater than <NUM>/(hour*cm<NUM>), or equal to or greater than <NUM>/(hour*cm<NUM>). The volatile material transfer rate of the membrane may range between any combination of these upper and lower values. For example, the volatile material transfer rate of the membrane <NUM> may be from <NUM> to <NUM>/(hour*cm<NUM>), or from <NUM> to <NUM>/(hour*cm<NUM>), or from <NUM> to <NUM>/(hour*cm<NUM>), in each case inclusive of the recited values.

The vapor release surface <NUM> may be substantially free of volatile material in liquid form. This is determined by the following procedure (e.g., using a sweat rating). Every <NUM> hours for at least <NUM> days, the exterior membrane surface on each assembly was visually inspected for liquid accumulation. The sweat rating used a numbering system, with "<NUM>" being no liquid accumulation; "<NUM>" being liquid accumulation on the substrate alone; "<NUM>" having liquid accumulation on the substrate and the ring gasket of the holder; and "<NUM>" having liquid accumulation on the substrate, seal and bottom metal lip of the holder. The average of all evaluations over time was used to determine the average sweat rating.

The treated membranes <NUM> shown in <FIG> may be configured for use in a fragrance delivery device. The fragrance delivery device may include an odorous volatile material (as previously described) contained in a reservoir. The volatile material contact surface <NUM> of the treated membrane <NUM> (having the first hydrophobic/oleophobic material <NUM>) may be in contact with the volatile material in liquid or solid form. The vapor release surface <NUM> of the treated membrane has the hydrophilic coating <NUM> (<FIG>). IIn this way, one side of the treated membrane <NUM> (the volatile material contact surface <NUM> or the vapor release surface <NUM>) may have the hydrophobic/oleophobic material <NUM>, while the other of the volatile material contact surface <NUM> and the vapor release surface <NUM> has the hydrophilic coating <NUM>.

The fragrance delivery device may include a removable cap layer having a first and second surface. An adhesive layer may be interposed between the vapor release surface <NUM> of the membrane <NUM> and the second surface of the cap layer, such that the membrane <NUM> and volatile material are beneath the cap layer. The removable cap may be a peel seal which, optionally, includes a tab in order to facilitate removal from the membrane <NUM>, thereby exposing the membrane <NUM> to activate the evaporative delivery of the volatile material. The cap layer may include at least one layer selected from the group consisting of metal foils, polymeric films, and combinations thereof. For example, the cap layer may include at least one polymeric film which has been printed or coated to appear metallized or "foil-like". Any know metal foils may be used, provided desired properties are achieved. Suitable polymeric films may include, but are not limited to, polyethylene film, polypropylene film, poly(ethylene terephthalate) film, polyester film, polyurethane film, poly(ester/urethane) film, or poly(vinyl alcohol) films. Any suitable polymeric film may be used, provided the desired properties are achieved. The cap layer also may include a metallized polymeric film either alone or in combination with a metal foil layer, a polymeric film layer, or both. The cap layer may include one layer or more than one layer in any combination.

The adhesive layer may include any of the known adhesives provided that the adhesive provides sufficient tack to keep the device sealed until activation by the consumer, while maintaining the removability of the cap layer. In a particular embodiment, the adhesive layer may include a pressure-sensitive adhesive ("PSA"), such as any of the PSA materials known in the art. Suitable PSA materials may include rubber-based adhesives, block co-polymer adhesives, polyisobutene-based adhesives, acrylic-based adhesives, silicone-based adhesives, polyurethane-based adhesives, vinyl-based adhesives, and mixtures thereof.

The treated membrane <NUM> of the fragrance delivery device may be configured to release odorous vapor from the vapor release side <NUM> of the treated membrane as the volatile material on the volatile material contact surface <NUM> penetrates through the treated membrane <NUM>. The vapor release side <NUM> may be substantially free of volatile liquid. The treated membrane <NUM> may have a volatile material transfer rate within the range previously recited to as to release the odorous vapor at the desired rate.

The treated membrane <NUM> may also be configured for use in liquid-liquid or solid-liquid separation. In one example, the treated membrane <NUM> may be used for oil-water separation. In other examples, the treated membrane <NUM> may be used in membrane distillation or gas venting.

The treated membrane <NUM> as previously described may be prepared using any suitable method.

According to one non-limiting embodiment, the treated membrane <NUM> may be prepared by providing the membrane <NUM> having the first side <NUM> and the second side <NUM>. The membrane <NUM> is made of the previously described thermoplastic organic polymer including a polyolefin. The membrane <NUM> defines a network of interconnecting pores communicating substantially throughout the membrane <NUM>. The membrane <NUM> includes the previously described particulate filler distributed throughout the membrane <NUM>.

The membrane <NUM> may optionally be pre-treated, such as using the previously described hydrophilic composition. The pre-treatment may be applied using any method, and, in one embodiment, the membrane <NUM> is dipped in the pre-treatment. The pre-treated membrane <NUM> may be dried after the pre-treatment is applied and prior to applying any further materials.

The first hydrophobic/oleophobic material <NUM> is applied to at least a portion of the first side <NUM> and optionally the second side <NUM> of the membrane <NUM> (pre-treated or not). The first hydrophobic/oleophobic material <NUM> may be applied using any method, and in one embodiment is applied to only the first side <NUM> using a drawdown method. In another example, the first hydrophobic/oleophobic material <NUM> may be applied by dipping the membrane <NUM> in the first hydrophobic/oleophobic material <NUM>.

The hydrophilic coating <NUM> is applied to at least a portion of the second side <NUM> of the membrane <NUM> (pre-treated or not). The hydrophilic coating <NUM> may be applied using any method, and in one example is applied to only the second side <NUM> using a drawdown method.

The second hydrophobic/oleophobic material <NUM> may be applied to at least a portion of the first side <NUM> and/or the second side <NUM> of the membrane <NUM> (pre-treated or not). The second hydrophobic/oleophobic material <NUM> may be applied using any method, and in one example is applied to only the second side <NUM> using a drawdown method. In another example, the second hydrophobic/oleophobic material <NUM> may be applied by dipping the membrane <NUM> in the second hydrophobic/oleophobic material <NUM>. The first hydrophobic/oleophobic material <NUM> may be the same or different from the second hydrophobic/oleophobic material <NUM>.

The following examples are presented to exhibit the general principles of the invention. The invention should not be considered as limited to the specific examples presented. All parts and percentages in the examples are by weight unless otherwise indicated.

Compositions of filled microporous membranes are shown in Table <NUM> below.

The dry ingredients specified in Table <NUM> were weighed into a FM-130D Littleford plough blade mixer with one high intensity chopper style mixing blade. The dry ingredients were premixed for <NUM> seconds using the plough blades only. The process oil was then pumped in over <NUM>-<NUM> seconds via a hand pump through a spray nozzle at the top of the mixer, with only the plough blades running. The high intensity chopper blade was turned on, along with the plough blades, and the mix was mixed for <NUM> seconds, the mixer was shut off and the internal sides of the mixer were scraped down to ensure all ingredients were evenly mixed. The mixer was turned back on with both high intensity chopper and plough blades turned on, and the mix was mixed for an additional <NUM> seconds. The resultant mixtures were extruded as described in Step <NUM>.

The mixes of the Examples <NUM>-<NUM> were extruded and calendered into the final sheet form using an extrusion system including a feeding, extrusion and calendering system described as follows. A gravimetric loss in weight feed system (K-iron model #K2MLT35D5) was used to feed each of the respective mixes into a <NUM> twin screw extruder (model # was Leistritz Micro-27gg). The extruder barrel was comprised of eight temperature zones and a heated adaptor to the sheet die. The extrusion mixture feed port was located just prior to the first temperature zone. An atmospheric vent was located in the third temperature zone. A vacuum vent was located in the seventh temperature zone.

The mix was fed into the extruder at a rate of <NUM>/minute. Additional processing oil also was injected at the first temperature zone, as required, to achieve the desired total oil content in the extruded sheet. The oil contained in the extruded sheet (extrudate) being discharged from the extruder is referenced herein as the "extrudate oil weight percent".

Extrudate from the barrel was discharged into a <NUM>-centimeter wide sheet Masterflex® die having a <NUM> millimeter discharge opening. The extrusion melt temperature was <NUM>-<NUM> and the throughput was <NUM> kilograms per hour.

The calendering process was accomplished using a three-roll vertical calender stack with one nip point and one cooling roll. Each of the rolls had a chrome surface. Roll dimensions were approximately <NUM> in length and <NUM> in diameter. The top roll temperature was maintained between <NUM> to <NUM>. The middle roll temperature was maintained between <NUM> to <NUM>. The bottom roll was a cooling roll wherein the temperature was maintained between <NUM>-<NUM>. The extrudate was calendered into sheet form and passed over the bottom water cooled roll and wound up.

A sample of sheet cut to a width up to <NUM> and length of <NUM> was rolled up and placed in a canister and exposed to hot liquid <NUM>,<NUM>,<NUM>-trichloroethylene for approximately <NUM>-<NUM> hours to extract oil from the sheet sample. Afterwards, the extracted sheet was air dried and subjected to test methods described hereinafter.

Hydrophilic coating composition 2A: Poly (<NUM>-ethyl-<NUM>-oxazoline), (<NUM>, weight average molecular weight (Mw) ~ <NUM>,<NUM>) was dispersed in cool water (<NUM>) under mild agitation in a <NUM> beaker. The mixture was stirred for <NUM> hours, followed by addition of PLURONIC®17R2 (<NUM>, a Block Copolymer Surfactant available from BASF (Ludwigshafen, Germany)) and <NUM>-butoxyethanol (<NUM>), after which the resultant solution was stirred for an additional <NUM> minutes.

Hydrophilic coating composition 2B: SELVOL® <NUM> (<NUM>, polyvinyl alcohol available from Sekisui Specialty Chemicals America (Dallas, TX)) was dispersed in cool water (<NUM>) under mild agitation in a <NUM> beaker using a <NUM> inch (<NUM>) paddle stirrer driven by an electric stir motor. The mixture was heated to <NUM>°F (<NUM>) and stirred for approximately <NUM> minutes until completely dissolved. The resultant solution was cooled to room temperature with stirring.

Hydrophobic/oleophobic coating composition 2C: UNIDYNE® <NUM> (<NUM>, available from Daikin America, Inc. (Orangeburg, NY)) was dispersed in cool water (<NUM>) under mild agitation in a <NUM> beaker.

All membranes were cut to <NUM> x <NUM>-inch [<NUM> x <NUM>] sheets prior to treatment with any coating composition. Examples <NUM>-<NUM> comprise hydrophobic/oleophobic composition 2C. Examples <NUM>-<NUM> were first treated with hydrophilic composition 2A prior to application of the hydrophobic/oleophobic composition 2C. Examples <NUM>-<NUM> were coated on only one side with the hydrophobic/oleophobic composition 2C, while Example <NUM> was coated on both sides.

For Examples <NUM>-<NUM>, hydrophilic composition 2A was applied directly to the membrane prepared in Part <NUM> as indicated in Table <NUM>. The <NUM> x <NUM>-inch [<NUM> x <NUM>] sheet was immersed into composition 2A for a period of five minutes, after which the sheet was removed, and excess solution was allowed to drip off. The coated microporous material was then clamped on an aluminum frame which was fitted with a gasket to prevent the film from shrinking during drying. The framed membrane was then dried in an oven at <NUM> for <NUM> minutes.

Example <NUM>, as well as the membranes of Examples <NUM>-<NUM> treated above, were then treated with the hydrophobic/oleophobic composition 2C. For Example <NUM>, the membrane indicated in Table <NUM> was coated without prior treatment. For Examples <NUM>-<NUM>, the hydrophobic/oleophobic composition was applied to the previously treated membranes described above. In each case, the <NUM> x <NUM>-inch [<NUM> x <NUM>] sheet was placed on a clean glass surface and taped along the short side.

Composition 2C was applied directly to the microporous substrate or, where indicated, the microporous substrate treated with composition 2A. Each substrate had been tared on a balance prior to placing the sheet, Side A facing up, on a clean glass surface and using tape to adhere the top corners of the sheet to the glass. A piece of clear <NUM> mil thick polyester <NUM> inch (<NUM>) x <NUM> inch (. <NUM>) was positioned to overlap across the top edge of the sheet and affixed to the glass surface with tape. A wire wrapped metering rod #<NUM> from Diversified Enterprises was placed on the polyester near the top edge. A <NUM> to <NUM> quantity of coating was deposited as a bead strip (approximately ¼ inch (<NUM>) wide) directly next to and touching the metering rod using a disposable pipette.

The bar was drawn down across the sheet at approximately a constant rate. The resultant wet sheet was removed from the glass surface, immediately placed on the previously tared balance, weighed, then placed in a forced air oven and dried at <NUM> for <NUM> minutes. The dried sheet was removed from oven and the same coating procedure was repeated on Side B only for Example <NUM>.

The Comparative Examples were left uncoated, or coated with hydrophilic coatings only. Comparative Example <NUM> and Comparative Example <NUM> were both treated with Composition 2A as described above. Comparative Example <NUM> was coated on Side A with an additional hydrophilic solution, 2B, which was applied in the same manner as described for composition 2C above. Comparative Example <NUM> was provided, which was a PVDF membrane fused with a super hydrophobic composition. This material is commercially available as DURAPEL® GVSP, available from MilliporeSigma (Billerica, MA).

Each of the membranes, treated membranes, and comparative untreated membranes were characterized by testing the physical properties described below.

Gurley Porosity: This test was performed on dry membrane samples. Porosity was determined using a Gurley Precision Densometer, model <NUM>, manufactured by GPI Gurley Precision Instruments (Troy, NY). The Porosity reported was a measure of the rate of air flow through a sample or it's resistance to an air flow through the sample. The unit of measure is a "Gurley second" and represents the time in seconds to pass <NUM> cc of air through a <NUM> inch square area using a pressure differential of <NUM> inches of water. Lower values equate to less air flow resistance (more air is allowed to pass freely, e.g., more porous). The measurements were completed using the procedure listed in the manual, MODEL <NUM> Automatic Densometer and Smoothness Tester Instruction Manual. TAPPI method T <NUM> om-<NUM>-Air Resistance of Paper can also be referenced for the basic principles of the measurement.

Density: The density of the above-described examples was determined by dividing the average weight of two specimens measuring <NUM>×<NUM> inches (<NUM>×<NUM>) that were cut from each sample by the average volume of those specimens.

Pore size: The volume average diameter of the pores of the microporous material was determined by mercury porosimetry using an Autoscan mercury porosimeter (Quantachrome Instruments (Boynton Beach, FL)) in accordance with the operating manual accompanying the instrument. The volume average pore radius for a single scan was determined automatically by the porosimeter. In operating the porosimeter, a scan was made in the high pressure range (from <NUM> kilopascals absolute to <NUM> megapascals absolute). If <NUM> percent or less of the total intruded volume occurred at the low end (from <NUM> to <NUM> kilopascals absolute) of the high pressure range, the volume average pore diameter was taken as twice the volume average pore radius determined by the porosimeter. Otherwise, an additional scan was made in the low pressure range (from <NUM> to <NUM> kilopascals absolute) and the volume average pore diameter was calculated according to the equation: <MAT> where, d is the volume average pore diameter; v <NUM> is the total volume of mercury intruded in the high pressure range; v <NUM> is the total volume of mercury intruded in the low pressure range; r<NUM> is the volume average pore radius determined from the high pressure scan; r<NUM> is the volume average pore radius determined from the low pressure scan; w<NUM> is the weight of the sample subjected to the high pressure scan; and w<NUM> is the weight of the sample subjected to the low pressure scan.

Contact angle: was measured on a VCA 2500XE video contact angle system, available from AST Products, Inc. (Billerica, MA) using <NUM> microliter of ultrapure water. On all samples, contact angle was measured on Side A.

Oil rating: was measured with AATCC test method <NUM>-<NUM>. In cases where Sides A and B were different, the oil rating was measured on Side A.

The holder assembly used for evaporation rate and performance testing of a membrane consisted of a front clamp with a ring gasket, a back clamp, test reservoir cup, and four screws. The test reservoir cup was fabricated from a clear thermoplastic polymer, having interior dimensions defined by a circular diameter at the edge of the open face of approximately <NUM> centimeters and a depth of no greater than <NUM> centimeter. The open face was used to determine the volatile material transfer rate.

Each clamp of the holder assembly had a <NUM> inch (<NUM>) diameter circular opening to accommodate the test reservoir cup and provide an opening to expose the membrane under test. When placing a membrane under test, the back clamp of the holder assembly was placed on top of a cork ring. The test reservoir cup was placed in the back clamp and charged with an amount of benzyl acetate as described below, used to simulate fragrance compositions. In Table <NUM>, where "full" testing is indicated, <NUM> benzyl acetate was placed in the reservoir. "Quarter" testing indicated the placement of <NUM> benzyl acetate in the reservoir. An approximately <NUM> inch (<NUM>) diameter disk was cut out of the membrane sheet and placed directly over and in contact with the edge of the reservoir cup such that <NUM><NUM> of the surface (side of interest) of the microporous sheet was exposed to the interior of the reservoir. When a coated microporous sheet was used, the membrane was oriented such that Side A was exposed to the interior of the reservoir, with the exception of Example 5B, where the Side B was exposed to the interior of the reservoir.

The front clamp of the holder was carefully placed over the entire assembly, with the screw holes aligned and so as not to disturb the membrane disk. The screws were attached and tightened enough to prevent leaking. The ring gasket created a seal. Five replicates were assembled for each membrane tested.

Each holder assembly was weighed to obtain an initial weight of the entire charged assembly. The assembly was then placed upright such that the membrane was oriented vertically and benzyl acetate was in direct contact with at least a portion of the test membrane. The upright (vertically oriented) assembly was placed in an environment defined below according to the airflow, maintained at <NUM>° ± <NUM>. The humidity within in environment was ambient. The test reservoirs were weighed every <NUM> hours for a minimum of <NUM> days. The calculated weight loss of benzyl acetate over the entire time period, in combination with the elapsed time and surface area of the microporous sheet exposed to the interior of the test reservoir, were used to determine the volatile material transfer rate of the microporous sheet, in units of mg/(hour*cm<NUM>). The average evaporation rate (mg/hr) of the replicates was determined for the entire assembly in Table <NUM>. The average evaporation rate was converted to volatile material transfer rate according to the following formula: <MAT>.

The reported values in Table <NUM> are the average of all five samples over the entire testing period.

Examples tested under "non-restricted" conditions were placed laboratory chemical fume hood having approximate dimensions of <NUM> feet (<NUM>) (height)×<NUM> (<NUM>) feet (width)×<NUM> (<NUM>) feet (depth). The glass doors of the fume hood were pulled down, and the air flow through the hood was adjusted so as to have eight (<NUM>) turns (or turnovers) of hood volume per hour.

Examples tested under "restricted" conditions were placed in a HDPE enclosed box, having approximate dimensions of <NUM> inches (<NUM>) (height) × <NUM> inches (<NUM>) (width) × <NUM> inches (<NUM>) (depth). Enclosing the container was an <NUM> × <NUM> inch (<NUM> x <NUM>) cardboard sheet, wrapped with duct tape.

Concurrent with the volatile material transfer rate testing, every <NUM> hours for at least <NUM> days, the exterior membrane surface on each assembly was visually inspected for liquid accumulation. The sweat rating used a numbering system, with "<NUM>" being no liquid accumulation; "<NUM>" being liquid accumulation on the substrate alone; "<NUM>" having liquid accumulation on the substrate and the ring gasket of the holder; and "<NUM>" having liquid accumulation on the substrate, seal and bottom metal lip of the holder. The average of all evaluations over time for all five replicates were used to determine the average sweat rating reported below in Table <NUM>.

Claim 1:
A treated vapor permeable microporous membrane comprising:
a microporous membrane comprising a first side and a second side opposite the first side, the membrane comprising a thermoplastic organic polymer comprising a polyolefin, the membrane defining a network of interconnecting pores communicating substantially throughout the membrane;
finely divided, substantially water-insoluble particulate filler having less than <NUM>/L solubility in pure water at <NUM> distributed throughout the membrane and constituting <NUM> to <NUM> weight percent of the membrane, based on the total weight of the membrane and the particulate filler, wherein the particulate filler comprises siliceous particles comprising particulate silica;
a first hydrophobic/oleophobic material applied over at least a portion of the first side, the first side over which the first hydrophobic/oleophobic material is applied demonstrating a water contact angle of at least <NUM>° using Kruss Drop Shape Analysis and/or an oil rating of at least <NUM> based on AATCC test method <NUM>-<NUM>; and
a hydrophilic coating over at least a portion of the second side, the second side over which the hydrophilic coating has been applied demonstrating a water contact angle of less than <NUM>° using Kruss Drop Shape Analysis;
wherein the polyolefin constitutes at least <NUM> weight percent of the membrane, based on the total weight of the membrane and the particulate filler,
wherein the membrane has a mean pore size determined by mercury porosimetry of up to <NUM>, and
wherein the first hydrophobic/oleophobic material comprises at least one fluoro-alkyl group.