MXPA97006750A - Article humedeci - Google Patents

Abstract

A wettable article consisting of an article with a hydrophobic surface having a coating which includes a surface free energy modifier and a surfactant. The hydrophobic surface may include a hydrophobic polymer. The surface free energy modifier has a surface free energy greater than that of the surface of the article, but not less than the surface tension of an aqueous liquid to which the wettable coated article can be exposed. The surface free energy modifier is desirably present in an amount sufficient to essentially cover the surface of the article. The surfactant is present in an amount effective to lower the surface tension of the liquid to a value which is greater than the surface free energy of the article surface and equal to or less than the surface free energy of the free energy modifier of the article. surface. The article is desirably a film or fibrous tissue, such as a non-woven fabric. It also describes the methods to prepare the article humidification

Description

HÜMEDECIBLE ARTICLE Background of the Invention The present invention relates to an article, such as a film or a fibrous tissue. The polymers are used extensively to make a variety of products which include blown and cast films, extruded sheets, molded articles for injection, foams, blow molded articles, extruded pipes, monofilaments, and non-woven fabrics. Some such polymers, such as polyolefins, are naturally hydrophobic, and for many uses this property is either a positive attribute or at least not a disadvantage.

There is a large number of uses for polymers, however, where their hydrophobic nature either limits their usefulness or requires some effort to modify the surface characteristics of the articles made with them. By way of example, polyolefins, such as polyethylene and polypropylene, are used to make polymeric fabrics which are employed in the construction of such disposable absorbent articles as diapers; incontinence care products; women's care products, such as sanitary napkins and tampons; the filter elements; the cloths; drapes and surgical gowns; the protection pads; bandages of wounds, such as bandages; and similar. Such polymeric fabrics are often non-woven fabrics prepared by, for example, such processes as melt blowing, coformming and spun bonding. Frequently, such polymeric fabrics require being water-moistening. Wettability can be obtained by spraying or otherwise coating the fabric (for example, by treating the surface or by treating it topically, with a surfactant solution during or after its formation, and then drying the fabric.

Some of the most common surfactants applied topically are nonionic surfactants, such as polyethoxylated octylphenols and condensation products of polypropylene oxide with propylene glycol, by way of illustration only. These surfactants are effective to be wettable to normally hydrophobic polymeric fabrics. However, the surfactant is easily removed from the fabric, often only after a single exposure to an aqueous liquid.

The essential efforts have been directed to increase the durability of the surfactants which are applied topically to a polymeric fabric. Such efforts include the following by way of illustration: (1) the use of a composition which includes water, a primary surfactant and a cosurfactant which is functional to moisten the fabric with the composition and which provides an essentially uniform distribution of the surfactant primary on the polymeric fabric; (2) the use of a surfactant, with or without a non-ionic cosurfactant, which is the reaction product of an acid anhydride derivative, such as a substituted succinic anhydride, with a polyhydroxy compound, such as a sorbitol, a polyethylene glycol, a triethanolamine, a polyhydroxyamine, certain primary and secondary amines, and certain unsaturated sulfoaliphatic compounds; (3) the use of a surfactant, with or without a nonionic cosurfactant, which is the reaction product of certain unsaturated sulfoaliphatic compounds with the reaction product of an acid anhydride derivative, such as a substituted succinic anhydride, with a polyamide having at least one NH group capable of addition to a double bond; (4) the use of a surfactant mixture which includes an ester-acid, an ester salt, or a mixture thereof, and an amide acid, anodic salt, or a mixture thereof, with or without a cosurfactant non-ionic; and (5) the use of a surfactant mixture which includes a sorbitol succinate surfactant, such as an ethoxylated amino sorbitol amino succinate salt or an ethoxylated fatty amine salt of succinate alkenyl anhydride, and a co-suppressant auxiliary which can be example, a silicone polyether or a primary or secondary alcohol having up to about 8 carbon atoms.

In addition to wettability with water, many absorbent products, for example porous, are related, at least to some degree, to the rate at which the aqueous liquid penetrates the porous product. For example, when the porous product is a non-woven fabric or other fibrous material, the liquid must penetrate between the fibers of the fabric. A porous substrate in which an aqueous liquid penetrates at a rapid rate will be more effective in absorbing large volumes of liquid delivered over a short period of time, and, as a consequence, more effective in preventing or minimizing runoff. In addition, a porous substrate which rapidly absorbs the liquid will allow other components of an absorbent product to more effectively move the liquid out from the location of the liquid insult to the rest of the absorbent product. Therefore, more of the absorbent product will be available for the absorption of the liquid.

It is known that the penetration rate of a liquid inside a porous substrate is directly proportional to the surface tension of the liquid and the cosine of the contact angle that the liquid makes with the surface of the substrate (see, for example, AW Adamson, Chapter XIII, "Wetting, Flotation and Detergency" in "Surface Physical Chemistry", Fifth Edition, by John Wiley &Sons, York, 1990, pages 495-496). By lowering the surface tension of the liquid, it therefore has an adverse effect on the liquid penetration rate. This is when the surface tension of the liquid is decreased, the liquid penetration driving force is also decreased. The cosine of the contact angle, on the other hand, is at a maximum value of 1 when the contact angle is zero. As the contact angle increases, the cosine decreases, approaching zero when the contact angle approaches 90o.

The methods for making a polymeric wettable substrate as described above all involve reducing the surface tension of the liquid to a value which is approximately the same or lower than the surface free energy of the substrate to be wetted by the liquid . Such methods also lower the contact angle. However, as already noted, lowering both the surface tension of the liquid and the contact angle is counterproductive with respect to the liquid penetration rate. Therefore, there is a need for materials which are wettable and exhibit a rapid intake of the liquid.

Synthesis of the Invention The present invention addresses some of the difficulties and problems discussed above by providing a wettable article which also has a rapid rate of liquid penetration. Fast liquid penetration properties and wettability are achieved by minimizing the reduction in surface tension of an aqueous liquid that comes in contact with the article while maintaining a small contact angle that the liquid makes with the surface from the article.

Thus, the present invention provides a wettable article consisting of an article with a hydrophobic surface having a coating which includes a surface free energy modifier and a surfactant. The hydrophobic surface may be composed of a hydrophobic polymer. The surface free energy modifier has a surface free energy greater than that of the surface of the article, but less than the surface tension of an aqueous liquid to which the wettable article may be exposed, and desirably present in a sufficient amount to cover essentially the surface of the article. The surfactant is present in an amount effective to lower the surface tension of the liquid to a value which is greater than the surface free energy of the article surface and equal to or less than the surface free energy of the free energy modifier. Of surface.

The article may be, by way of example only, a film or a fibrous sheet. The fibrous sheet may be a woven or non-woven fabric. The hydrophobic polymer can be, by way of example, a polyolefin. Typical polyolefins are polyethylene and polypropylene. Also by way of example, the surface free energy modifier can be a protein and the surfactant can be a polyethoxylated alkylphenol.

The present invention also provides a method for preparing a wettable article. The method involves forming an article by melt extrusion, at least a portion of which is formed of a polymeric composition which includes a hydrophobic polymer and a surfactant adapted to migrate to a surface of the article; and coating the surface of the article with a surface free energy modifier.

By way of example, the free surface energy modifier may have a surface free energy greater than that of the surface of the article, but less than the surface tension of an aqueous liquid to which the wettable article may be exposed. As another example, the free surface energy modifier may be present in an amount sufficient to essentially cover the surface of the article.

The method may include the additional step of causing the surfactant to migrate to the surface of the article in an amount effective to lower the surface tension of the liquid to a value which is greater than the surface free energy of the surface of the article. equal to or less than the surface free energy of the surface free energy modifier.

The present invention further provides a method for preparing a wettable article which involves forming an article by melt extrusion, wherein the article has a hydrophobic surface; coating the surface of the article with a surface free energy modifier; and treating the coated article with a surfactant. For example, the free surface energy modifier may have a surface free energy greater than that of the surface of the article, but less than the surface tension of an aqueous liquid to which the wettable article may be exposed. As another example, the surfactant may be present in an amount effective to lower the surface tension of the liquid to a value which is greater than the surface free energy of the article surface and equal to or less than the surface free energy. of the modifier? e surface free energy.

The wettable article of the present invention can be used as a component of a disposable absorbent product. The disposable absorbent product may be, for example, a diaper, a feminine care product, or an incontinence product.

Detailed description of the invention As used herein, the terms "article" and "product" are synonymous and are intended to mean including any article or product which is formed by a melt extrusion process, regardless of the size or shape of the article. As a practical matter, the present disclosure is directed primarily to extruded films with melt, fibers, and non-woven fabrics composed of such fibers. Notwithstanding this, it is considered that other articles or products fall within the spirit and scope of the present invention.

In those embodiments in which the article is a non-woven fabric, such as a non-woven fabric in general, it can be prepared by any means known to those having ordinary skill in the art. For example, the nonwoven fabric can be prepared by such processes as melt blowing, coformming, spinning, hydroentanglement, carding, air laying and wet forming.

The non-woven fabric will most typically be a non-woven fabric prepared by melt blowing, coformming, spinning, and the like. By way of illustration only, such processes are exemplified by the following references which are incorporated herein by correlation: (a) meltblown references include, by way of example, US Pat. Nos. 3,016,599 issued to R. Perry, Jr., 3,704,198 granted to J. S. Prentice, 3,755,527 granted to J. P. Keller and others, 3,849,241 granted to R. R. Butin and others, 3,978,185 granted to R. R. Butin and others, and 4,663,220 granted to T. J. Wisnes i and others. Also see the work of V. A. Wente, "Superfine Thermoplastic Fibers", Industrial Chemistry and Engineering. Volume 48, No. 8, pages 1342-1346 (1956); VA Wente et al., "Manufacture of Superfine Organic Fibers", Naval Research Laboratory, Washington, DC, Naval Research Laboratory Report 4364 (111437), dated May 25, 1954, United States Department of Commerce , Technical Services Office; and Robert R. Butin and Dwight T. Lohkamp, "Blow Molding - A One-Step Tissue Process for New Non-Woven Products", Journal of the Pulp and Paper Industry Technical Association. Volume 56, No. 4, pages 74-77 (1973); (b) the references of the coformmation include the patents of the United States of North America Nos. 4,100,324 granted to R. A. Anderson and others, and 4,118, 531 granted to E. R. Hauser; Y (c) yarn union references include, among others, US Pat. Nos. 3,341,394 issued to Kinney, 3,655,862 issued to Dorschner et al., 3,692,618 issued to Dorschner et al., 3,705,058 issued to Dobo and others, 3,802,817 granted to Matsuki and others, 3,853,651 granted to Porte, 4,064,605 granted to Akiyama 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, 4,627,811 granted to Greiser and Wagner and 4,644,045 granted to Fowells.

The term "hydrophobic polymer" is used herein to mean any polymer resistant to wetting or that is not easily moistened, by water, for example, having a lack of affinity with water. A hydrophobic polymer will typically have a surface free energy of about 40 dynes / cm (40 x 10"5 newtons / cm or N / cm) or less.Examples of hydrophobic polymers include, by way of illustration only, polyolefins such as polyethylene, poly (isobutene), poly (isoprene), poly (4-methyl-1-pentene), polypropylene, ethylene-propylene copolymers, ethylene-propylene-hexadiene copolymers, and ethylene-vinyl acetate copolymers; of styrene, such as poly (styrene), poly (2-tnethylstyrene), styrene-acrylonitrile copolymers having less than about 20 mole-percent acrylonitrile, and styrene-2, 2, 3, 3, -tetrafluoropropyl copolymers methacrylate; halogenated hydrocarbon polymers, such copoly (chlorotrifluoroethylene), copolymers of chlorotrifluoroethylene tetrafluoroethylene, poly (hexaf luoropropylene), poly (tetrafluoroethylene), copolymers of tetrafluoroethylene-ethylene, poly (trifluoroethylene) o), poly (vinyl fluoride), and poly (vinylidene fluoride); vinyl polymers such as poly (vinyl butyrate), poly (vinyl decanoate), poly (vinyl dodecanoate), poly (vinyl hexadecanoate), poly (vinyl hexanoate), poly (vinyl propionate), poly (octanoate) vinyl), poly (heptafluoroisopropoxy ethylene), 1-heptafluoroisopropoxymethylethylene-copolymers of acidic, poly (heptaf luoroisopropoxypropylene), poly (methacrylonitrile), poly (vinyl alcohol), poly (vinyl butyral), poly (ethoxyethylene), poly (methoxyethylene) , and poly (vinyl formal); acrylic polymers such as, poly (n-butyl acetate), poly (ethyl acrylate), poly [(l-chlorodi f luorome i lo) -te t raf luoroet i acrylate], poly [di (chloroforomethyl) fluoro-methyl acrylate], poly (1,1-dihydroheptafluorobutyl acrylate), poly (1,1-dihydropentaf luoroisopropyl acrylate), poly (1,1-dihydropentadecaf luorooctyl acrylate), poly (heptaf luoroisopropyl acrylate), poly [5- (heptaf luoroisopropoxy) pentyl acrylate], poly [11- (heptaf luoroisopropoxy) undecyl acrylate], poly [2- (heptafluoropropoxy) ethyl acrylate], poly (nonafluoroisobutyl acrylate); methacrylic polymers, such as poly (benzyl methacrylate), poly (n-butyl methacrylate), poly (isobutyl methacrylate), poly (t-butyl methacrylate), poly (t-butylaminoethyl methacrylate), polydodecyl methacrylate), poly (ethyl methacrylate) , poly (2-ethylhexyl methacrylate), poly (n-hexyl methacrylate), poly (dimethylaminoethyl methacrylate), poly (hydroxyethyl methacrylate), poly (phenylmethacrylate), poly (n-propyl methacrylate), poly (octadecyl methacrylate), poly ( 1-1-dihydropentadecaf luorooctyl methacrylate), poly (heptaf luoroisopropyl methacrylate), poly (heptadecaf luorooctyl methacrylate), poly (1-hydrotetrafluoroethyl methacrylate), poly (1,1-dihydrot and raf luoropropy methacrylate), poly (1-hydrohexaf luoroisopropyl methacrylate), and poly (t-nonaf luorobutyl methacrylate); polyethers, such as poly (doral), poly (oxybutene) diol, poly (oxyisobutene) diol, poly (oxidecamethylene) -dimethyl ether polymers having molecular weights below 1,500, poly (oxy-hexamethylene) diol, poly (oxypropylene) diol , poly (oxypropylene) -dimethyl ether and poly (oxytetramethylene); polyether copolymers, such as poly (oxyethylene) -poly (oxypropylene) -poly (oxyethylene) block copolymers, oxyethylene-oxypropylene copolymers having more than about 20 mole percent oxypropylene, oxytetramethylene-oxypropylene copolymers, and block copolymers having oxyethylene-oxypropylene copolymer blocks separated by a block (oxydimethylsilylene); polyamides, such as poly [imino (1 - or xode ca methylene], poly [imino (oxododecamethylene)] or nylon 12, poly [imino (1-oxohexamethylene)] or nylon 6, poly (imino (1-oxotetramethylene)] or nylon 4, poly (iminoazelaoi-1-iminononamet and wood), poly (i-inose-anilimino-demethylene), and poly (iminosuberoyl-i inooctamethylene), polyimines, such as poly [(benzoylimino) -ethylene], poly [(butyrylimino) ethylene], poly [(dodecanoyl-imino) ethylene], (dodecanoylimino) ethylene- (acetylimino) trimethylene copolymers, poly [(heptanoyl imino) ethylene], poly [(hexanoyl imino) ethylene], poly { [(3-methyl) butyrylimino] ethylene.}, poly [(pentadecaf luorooctadecanoyl imino) ethylene], and poly [(pent anoyl imino) ethylene]; polyurethanes, such as those prepared from methylene diphenyl diisocyanate and butanediol poly (oxytetramethylene) diol, hexamethylene diisocyanate and triethylene glycol and 4-methyl-1,3-phenylene diisocyanate and tripropylene glycol; polysiloxanes, such as poly (oxydimethylsilylene) and poly (oxymethylphenylsilylene); and cellulosics such as amylose, amylopectin, cellulose acetate butyrate, ethyl cellulose, hemicellulose, nitrocellulose, and starch.

As indicated above, the wettable article of the present invention includes an article having a surface composed of a hydrophobic polymer. Therefore, the term "surface" is used herein to mean that part of the total surface area of the article which is composed of a hydrophobic polymer. The surface of the article may encompass the entire surface area of the article or only a part thereof. For example, when the article is a non-woven fabric, the fibers of which the fabric is made can be prepared from a single hydrophobic polymer. Alternatively, such fibers can be bicomponent fibers, in which one component is a hydrophobic polymer and the other component is a different hydrophobic polymer or a non-hydrophobic polymer, for example, a hydrophilic polymer. The fibers may be bicomponent core-sheath fibers, in which case the sheath will typically be composed of a hydrophobic polymer. The fibers can also be bicomponent fibers side by side. In addition, the fibers of which the non-woven fabric is composed may have a circular or non-circular cross section. The fibers may also be polycomponent fibers provided that at least one component is a hydrophobic polymer.

The surface of the article of the present invention has a coating thereon. The coating includes a surface free energy modifier and a surfactant. The surface free energy modifier has a surface free energy greater than that of the surface of the article, but less, than the surface tension of an aqueous liquid to which the coated wetted article can be exposed, and is present in a sufficient amount to cover essentially the surface of the article. That is, the surface of the article is covered with the surface free energy modifier to such an extent that the surface free energy of the part of the article on which the liquid is stuck is the surface free energy of the free energy modifier of the product. surface, rather than the surface free energy of the hydrophobic polymer.

The free surface energy modifier can be any material which has a surface free energy greater than that of the surface of the article, but less than the surface tension of an aqueous liquid to which the wettable coated article can be exposed. Desirably, the surface free energy modifier will not be easily removed by the liquid environment. For example, when the hydrophobic polymer of which the surface is composed is a polyolefin, such as polypropylene, the surface free energy modifier can be a protein. The protein will desirably have a weight average molecular weight of at least about 10,000 Daltons. Examples of such proteins include, by way of illustration only, fibrinogen, such as simian plasma fibrinogen, bovine plasma fibrinogen, cat plasma fibrinogen, dog plasma fibrinogen, goat plasma fibrinogen, plasma fibrinogen Guinea pig, horse plasma fibrinogen, human plasma fibrinogen, mouse plasma fibrinogen, pig plasma fibrinogen, rabbit plasma fibrinogen, rat plasma fibrinogen, and sheep plasma fibrinogen; albumin, such as simian albumin, bovine albumin, cat albumen, chicken albumin, chicken egg albumin, dog albumin, goat albumin, guinea pig albumin, hamster albumin, horse albumin, human albumin, mouse albumin, pig albumin, rabbit albumin, rat albumin, monkey resus albumin, sheep albumin, turkey albumin, and turkey egg albumin; casein such as from bovine milk, goat milk casein, human milk casein, sheep milk casein, and a-, ß- and kappa-casein from bovine milk, hemoglobin, such as simian hemoglobin, bovine hemoglobin , cat hemoglobin, dog hemoglobin, non-poisonous snake hemoglobin, goat hemoglobin, horse hemoglobin, human hemoglobin, mouse hemoglobin, pig hemoglobin, pigeon hemoglobin, rabbit hemoglobin, rat hemoglobin, sheep hemoglobin, and turkey hemoglobin; and lysozyme, such as chicken white lysozyme, human milk lysozyme, and turkey egg white lysozyme.

The surface of the article can be coated with the free surface energy modifier through any known means. For example, the surface free energy modifier can simply be adsorbed onto the surface of the article. Another example, the surface free energy modifier may be covalently bound to the surface. As yet another example, the surface of the article can be modified to assist or to improve either adsorption or covalent attachment. Thus, the surface may be exposed to a corona or plasma field or to an electron beam or other ionizing radiation to assist either the adsorption or the covalent attachment of the surface free energy modifier to the surface of the article; see, for example, US Pat. Nos. 4,238,291 issued to Lowther, 3,754,117 issued to Walter, and 5,102,738 issued to Bell et al., each of which is "incorporated herein by reference.

The term "surfactant" is used herein with its usual meaning and includes a single surfactant or a mixture of two or more surfactants. If a mixture of two or more surfactants is employed, said agents may be selected from the same classes or from different classes, provided that the agents present in the mixture are compatible with each other.

In general, the surfactant is present in the coating in an amount effective to lower the surface tension of the liquid to a value which is greater than the free surface energy of the article surface and equal to or less than the free energy of the article. surface free energy modifier surface.

The surface active agent can be any surfactant known to those of ordinary skill in the art, including anionic, cationic and non-ionic surfactants. Examples of the anionic surfactants include, among others, straight and branched chain alkyl alkyl benzene sulphonates, straight and branched chain alkyl sulfates, and straight or branched chain alkyl ethoxy sulfates. Cationic surfactants include, by way of illustration, tallow trimethylammonium chloride. Examples of nonionic surfactants include, again by way of illustration only, alkyl polyethoxylates; polyethoxylated alkylphenols; the fatty acid ethanol amides; polysiloxane polyethers; and the complex polymers of ethylene oxide, propylene oxide and alcohols. Desirably, the surfactant will be a non-ionic surfactant.

A method of the present invention for preparing a wettable article involves forming an article by melt extrusion, at least a portion of which is formed of a polymeric composition which includes a hydrophobic polymer and a surface active agent adapted to migrate to the surface of article. The presence of the surfactant on the surface of the article immediately after its formation is acceptable, provided that (a) such a presence does not significantly interfere with the coating of the surface with a surface free energy modifier, described hereinafter. hereinafter, and (b) coating the surface with a surface free energy modifier results in a wettable article as defined herein. Desirably, the migration of the surfactant takes place only after an event of post-formation of induction of migration, as described hereinafter.

The amount of surfactant included in the hydrophobic polymer can vary over a wide range. For example, the surfactant may be present in an amount of from about 0.01 to about 3 weight percent, based on the hydrophobic polymer. As a further example, the surfactant can be present in an amount of from about 0.01 to about 1 percent by weight, based on the hydrophobic polymer. Still as another example, when the surfactant is a polyethoxylated alkylphenol, the surfactant will typically be present in an amount of from about 0.05 to about 0.4 percent by weight, based on the hydrophobic polymer. Notwithstanding the foregoing ranges, the use of any amount of surfactant resulting in a wettable surface is considered to fall within the scope of the present invention, provided that (a) the surfactant present on the surface does not interfere in an adversely significant manner. with surface coating with a surface free energy modifier or (b) an amount of surfactant remains in the hydrophobic polymer which can be induced to migrate to the surface as described herein. If the presence of the surfactant on the surface interferes significantly with the coating of the surface with a free energy modifier of. On the surface, the agent can be removed by, for example, washing the article with water before the coating process is carried out.

As noted above, the surface of the article is coated with a surface free energy modifier having a surface free energy greater than that of the surface of the article, but less than the surface tension of an aqueous liquid to which it may be exposed. the moisturized coated article, in an amount sufficient to cover essentially the surface of the article. The coating can be applied by means which are well known to those having ordinary skill in the art, depending on the nature of the modifier. For example, the surface can be coated with a protein by a simple topical treatment, such as embedding, spraying, brush application, offset and direct rotogravure printing, and doctor blade.

In the event that the coating step removes the surfactant from the surface of the article, or that the wettable article of the present invention does not result from the coating passing, an additional step may be employed. The additional step involves causing the surfactant to migrate through a post-formation event that induces migration to the surface of the article in an effective amount to lower the liquid surface tension to a value which is greater than the free energy. of surface area of the article and equal to or less than the surface free energy of the surface free energy modifier. An example of such a post-formation event is the coating of the surface with the surface free energy modifier, for example, a protein. However, the migration of the surfactant after surface coating is not rapid, and may require days or even weeks or months at room temperature (eg, 20o-25oC). The migration can be accelerated by heating the coated article at a temperature to the temperature at which either the free surface energy modifier or the article begins to degrade. The time in which the coated article is heated will depend on the temperature, with the heating time being inversely proportional to the heating temperature. For example, the coated article can be heated to a temperature of from about 50 ° C to about 100 ° C. * C for from from around 30 minutes to around 10 hours.

Another method of the present invention for preparing a wettable article involves forming an article by melt extrusion in which the article has a surface consisting of a hydrophobic polymer. The surface of the article is coated with a free surface energy modifier having a surface free energy greater than that of the surface of the article, but less than the surface tension of an aqueous liquid to which the wetted coated article can be exposed, in a sufficient amount to cover essentially the surface of the article. The coated article is then treated with a surfactant in an amount effective to lower the surface tension of the liquid to a value which is greater than the surface free energy of the article surface and equal to less than the surface free energy. of the free surface energy modifier.

The present invention is further described by the following examples. Such examples, however, should not be considered as limiting in any way the spirit or scope of the present invention. The water used in the examples was distilled deionized water having an uncorrected surface tension of 72.5 dynes / cm (72.5 x 10"5 newtons / cm) as determined by means of a Fisher Scientific Surface Tension 20 using a ring Platinum-Iridium du Nouy (Fisher Scientific Company, Pittsburgh, Pennsylvania).

Example 1 Two types of nonwoven fabric bonded by polypropylene spinning were prepared essentially as described in U.S. Patent No. 3,802,817 issued to Matsuki.; each fabric has a basis weight of 0.8 ounces per square yard osy (about 27 grams per square meter or gsm). The first, referred to herein as Fabric A was made of polypropylene which contained 0.13 percent by weight, based on the weight of the polypropylene, of an internally added surfactant, Triton® X-102 (Rohm and Haas Co., of Philadelphia , Pennsylvania). Second, Fabric B did not contain an internally added surfactant, but was otherwise identical to Fabric A. Each fabric was cut into 7-inch samples in the transverse direction (CD) by 10 inches in the machine direction (MD ) (about 18 cm in the transverse direction x 25 cm in the machine direction). Samples of each tissue were soaked individually for 7.5 minutes in 500 ml aliquots of 20 mM pH 7 of sodium phosphate buffer containing 0.2 mg of a source of bovine fibrinogen as supplied (Fraction I, Type IV, 58 percent protein, Catalog No. F4753, Sigma Chemical Company, St. Louis, Missouri) per milliliter of buffer. The soaked samples were identified as 1A1 and 1B1, respectively. The two samples were soaked with an aliquot of 500 ml and a total of eight samples were prepared. A sample of each fabric was further rinsed in water for 10 to 30 seconds and then passed through an Atlas Laboratory juicer with a 30 pound (13.6 kg) attachment point placement (Atlas Electric Devices Company, Chicago, Illinois); Samples were identified as 1A2 and 1B2, respectively. Another sample of each tissue was placed at the attachment point after the soaking of fibrinogen, then rinsed in water and placed at the attachment point a second time and identified as 1A3 and 1B3, respectively. The samples were hung in a fume hood to dry overnight. After drying, each sample was cut in half and one half was hung in a 70 ° C oven for about seven hours.

The critical surface tension of the wetting (CSTW) for each sample, before and after heating was determined by placing 3-6 drops of Politest surface tension liquids (Pillar Technologies, Hartland, Michigan) on each fabric. The tissue was considered wettable if the drops were significantly spaced or penetrated the tissue in one minute. The surface tension of the liquid Politest which moistened the tissue was recorded. When the water was the test fluid, the degree of wettability was recorded. Wetting was considered immediate if the penetration of all the drops occurred less than one second. Wetting was characterized as partial when some regions of the sample were wetted with water and other regions were not. The results are summarized in Table 1.

Table 1 Summary of CSTW Terminations CSTW before CSTW after Sample heating1 'heating * Fabric A 36 37 1A1 58 Immediately wettable 1A2 58 Immediately wettable 1A3 58 Immediately wettable Fabric B 36 36 1B1 58 40-50b 1B2 58 40-50"1B3 56-64b 40 'In dynes / cm (10"5 newtons / cm) bThe sample was not wettable at the upper value, but was wettable at the lowest value.The insufficient sample was available to be tested with the Politest surface tension liquids having intermediate values.

It is evident that the fibrinogen-coated samples prepared from Fabric A which contained a small amount of a surfactant, Triton® X-102, were wetted with water upon heating, whereas the samples of Fabric B coated with fibrinogen (lacking the surfactant) did not become wettable with water upon heating. Note that fibrinogen, a surface-free energy modifier, raised the free surface energy of the polypropylene fabric (for example, 36 dynes / cm or 36 x 10"5 newtons / cm) to 58 dynes / cm or 58 x 10"5 newtons / cm. The heating of the fibrinogen-coated fabrics containing surfactant caused said surfactant to migrate to the tissue surface, thereby making the fabric moistenable with water. However, in the absence of the surface free energy modifier, the surfactant did not migrate to the surface in an amount sufficient to render the fabric moistenable in water.

Example 2 A portion of about 3 inches x 3 inches (8 cm x 8 cm) of Sample 1A1 of Example 1 was heated in a 70oc oven for about 7 hours and identified as Sample 2A2. The sample was then soaked in 80 ml deionized and distilled water for about 25 hours and identified as Sample 2A3. The sample was then reheated in a 70oc oven for about 7 hours and identified as Sample 2A4. Two small regions of about 1 cm2 in size were removed from the sample after each of the above-mentioned procedures and subjected to electronic spectroscopy for chemical analysis (ESCA). The data from the electronic spectroscopy for the chemical analysis were collected by Evans East, of Plainsboro, New Jersey. A sample of the original A tissue (described in Example 1) was also characterized by ESCA by serving as a control. Moistening of Sample 1A1 before and after each procedure (eg, heat or soaking), were evaluated as described in Example 1. The results are summarized in Table 2.

Table 2 Synthesis of the CSTW and ESCA Determinations ESCA (atom% ratio) Show CSTW-1 1? / C Q / C Fabric A 36 0. .00 0.03 1A1 58 0. .17 0.30 2A2 Immediately wettable 0. .11 0.28 2A3 60 0, .17 0.27 2A4 Partially wet 0 .14 0.28 aIn dynes / cm (10"s newtons / cm).

The Fabric A will be remembered from Example 1, it was made of polypropylene containing a small amount of a surfactant. The coating of the tissue with fibrinogen (Sample 1A1) resulted in a tissue having an upper surface free energy even when the tissue was not yet wettable with water. Sample 2A2 obtained by heating Sample 1A1 was immediately wettable with water. The wettability with water, however, was lost with the soaking of the Sample (2A3). Heating Sample 2A3 to give a Sample 2A4 resulted in a partial wettability.

It is evident that the soaking step did not remove the fibrinogen coating from the tissue; in comparison to the CSTW results for Samples 1A1 and 2A3, in which the CSTW values of 58 and 60 respectively were obtained. This conclusion is also supported by the ESCA data in which the N / C ratios for the two samples were the same. The N / C ratios also indicate the migration of surfactant to the surface after the first heating step (the change from 0.17 to 0.11 for Samples 1A1 and 2A2, respectively, suggests that the surfactant is associated with the fibrinogen coating) , the removal of the agent by the soaking step (the change from 0.11 to 0.17 for Samples 2A2 and 2A3, respectively), and the migration of an additional but smaller amount of surfactant after the second heating step (the change of from 0.17 to 0.14 for Samples 2A3 and 2A4, respectively).

Example 3 The procedure of Example 2 was repeated, except that Sample 1A1 of Example 1 was replaced with Sample 1A3 of Example 1 (Sample 1A3 was a non-woven fabric prepared from polypropylene containing an internally added surfactant and which had been treated with a solution of aqueous fibrinogen, had passed through the attachment point, had been rinsed in water, and had been subjected to the attachment point again). The sample was heated in an oven "at 70oC for about 7 hours, soaked in 80 ml deionized distilled water (designated 3 / lA3 / h) with about 25 hours, air-dried, heated again to 70 ° C the oven for another 7 hours, and it was soaked one last time in an aliquot part of 80 ml deionized and fresh distilled water (designated 3 / lA3 / hsh) for 24 hours.The surface tension of the soaking water was measured before and after the fabric had been soaked by means of a Fisher Scientific surface tensiometer using a platinum-iridium du Nouy ring (Fisher Scientific Company, Pittsburgh, Pennsylvania).

A sample of Fabric A (described in Example 1) was also heated at 70 ° C for 7 hours, and then soaked for about 25 hours in water (tissue designated A / h) to provide control. Because Fabric A was not wettable by water, it was suspended below the surface of the water with a weight (steel nut). The surface tension of the soaked water before and after the fabric was soaked was determined with the weight pressure. The data is summarized in Table 3.

Table 3 Synthesis of Surface Tension Data Surface Tension3 Asua of Soak Before Soak After Soak 3 / lA3 / h 72.8 62.8 3 / lA3 / hsh 72.4 70.2 Fabric A / h 72.5 70.8 In dynes / cm (10 ~ 5 newtons / cm) The decrease in surface tension of soaked water after Sample 1A3 and Fabric A were heated and soaked indicates that the surfactant was present in the sample or tissue surfaces and dissolved in the soaking water during the soaking process; see the results for the soaked water 3 / lA3 / h and the water soaked fabric / A / h, respectively. The results indicate that the fibrinogen coating on Sample 1A3 contributed to the increased migration of the surfactant to the surface of the sample when compared to Fabric A. Also, the surface tension data for the first and second soaps for the Sample 1A3 suggest that less surfactant is available on the surface of the tissue after the second heating. This is consistent with the decrease in water wettability found after soaking and then heating Sample 1A1 for the second time as shown in Example 2 (see results for Samples 2A2 and 2A4).

Example 4 The procedure of Example 1 was repeated to produce the fibrinogen-coated samples of the Tissues A and B. Fabric A was made of polypropylene which contained 0.13 percent by weight based on the weight of the polypropylene of an internally added surfactant, Triton® X-102. Fabric B did not contain an internally added surfactant, but "that was otherwise identical to Fabric A. Each fabric was prepared essentially as described in United States Patent No. 3,802,817 issued to Matsuki and each fabric had a base weight of 0.8 ounces per square yard (about 27 grams per square meter). Each fabric was cut into 7-inch samples in the transverse direction by 10 inches in the machine direction (about 18 cm in the transverse direction x 25 cm in the machine direction). Samples of each tissue were individually soaked for 5 minutes in aliquots of 500 ml of 20 mM pH 7 of sodium phosphate buffer containing 0.2 mg of bovine fibrinogen source as supplied (Fraction I, Type IV, 58 percent protein, Catalog No. F4753, from Sigma Chemical Company, of St. Louis, Missouri) by my buffer. The soaked samples were identified as 4A1 and 4B1, respectively. Each sample was air dried in a fume hood. The samples were stored (aged) at room temperature and the critical wetting surface tension (CSTW) for each of Samples 4A1 and 4B1 was measured over time. Fabric A was included as a control. The results are summarized in Tables 4-6 inclusive.

Table 4 Effect of Aging on Sample 4A1 Aging Period3 CSTWb Asua Wetting 0 N / Dc Non-humidifying 2 64 N / D 15 70 N / D 30 N / D Partially humid 163 N / A Immediately wettable aIn days. b In dynes / cm (10 ~ 5 newtons / cm). c Not determined.

Table 5 Effect of Aging on Sample 4B1 Period of Añeiamiento3 CSTWb Humidity of Asua 1 N / Dc Non-humidifying 34 N / D Non-humidifying 55 N / D Non-humidifying 64 60 Non-humidifying aIn days. b In dynes / cm (10 ~ 5 newtons / cm). c Not determined.

Table 6 Effect of Aging on Tissue A Aging Period3 CSTWb Asua Wetting 4 N / Dc Non-humidifying 11 36 N / A 12 36 N / A aIn months. b In dynes / cm (10 ~ 5 newtons / cm). c Not determined.

This example showed that aging produces the same result as heating, even when much more slowly; that is, the aging results in a slow migration of surfactant to the surface of the sample. Note the increase in surface free energy for Sample 4A1 over time and the associated improvement in wettability in water. The migration of the surfactant did not occur to an appreciable extent in the absence of the fibrinogen coating (compare Table 6 with Table 4). Finally, the data in Table 5 demonstrate that the fibrinogen coating alone does not age to produce a wettable surface.

Example 5 The procedure of Example 1 was repeated, except that a number of different proteins, including fibrinogen, were employed, and the samples were air dried in a smoke hood after being coated. The period of soaking with the fibrinogen solution remained in 7.5 minutes, while for all other protein solutions a soaking period of 60 minutes was used. The other proteins included in this example were bovine serum albumin (BSA), Catalog No. A3350; β-Casein, Catalog No. C6905; Lysozyme, Catalog No. L6876; casein acid hydrolyzate, Catalog No. C9386, all from Sigma Chemical Company and hemoglobin, Catalog No. 100714, from ICN Biomedicals, Inc., of Irvine, California. The majority of the coated samples were heated in an oven at 70 ° C for 7 hours. The critical wetting surface tension (CSTW) for each sample, before and after heating, was determined as described in Example 1. The data is summarized in Table 7; The protein concentrations listed in the table are the amounts of protein source as supplied by my buffer.

Table 7 Synthesis of CSTW Determinations CSTW Protein Before After Tei gone Type Concentration- * heating "heating1 * A 36 36 A FibrintSgeno 0. 2 58 Immediately wet To BSA 1. 0 68 Partially wet A BSA 0. 1 N / Dc Partly wet A ß-Casein 1. 0 Partly wet Partially wet A Hemoglobin 0. 2 60-66d Immediately wet A Lysozyme 1 0 68 Partially wet A Casein hydrat; 40-50d < 40 B 36 36 B Fibrindrogen 0.2 56 40-44 * 1 B BSA 1.0 58 < 40 B / 3-Casein 1.0 ially Wetted Not Wet B Hemoglobin 0.2 60-66d 40-50 B Lysozyme 1.0 68 40 Casein hydrated 1.0 40 > 40 aIn mg protein source by my buffer solution. bIn dynes / cm (10"5 newtons / cm) ° Not determined. dThe sample did not get wet at a higher value, but it got wet at a lower value. Insufficient sample was available to test with Politest surface tension liquids having intermediate values.

All protein coatings on Fabric A, except jß-casein and the casein hydrolysates, became more wettable in the water after heating of the coated fabric. Fibrinogen and hemoglobin coatings gave the most pronounced increase in wet hydrophilicity.

Example 6 Triton® X-102 was applied topically to Fabrics A and B, both as part of and after treatment of the tissues with a fibrinogen solution as described in Example 1. Three different 0.2 mg / ml fibrinogen solutions were prepared with 20 mM pH 7 of sodium phosphate buffer. The first (Solution A) contained only fibrinogen, the second (Solution B) also contained 0.04 percent by weight, based on the weight of the Triton® X-102 buffer solution, and the third (Solution C) also contained 0.10 percent by weight, based on the weight of the buffer solution, of Triton® X-102. The tissue samples A and B were soaked in each solution as described in Example 1, placed in the un-rinse fastening point, and air-dried in a fume hood. In addition, samples of Fabrics A and B and samples of Fabrics A and B coated with fibrinogen were soaked for 1 minute in water containing 0.12 percent by weight, based on the weight of the water (Solution D), were placed in the attachment point, and air-dried in a fume hood. The critical wetting surface tension (CSTW) for each sample was determined as described in Example 1. The data is summarized in Table 8.

Table 8 Synthesis of CSWT Determinations Solution (s) Used (s) Woven A B C D CSWT * Water Wettability A --- - < 50 Not moistened A ... - < 50 Non-wettable A X - 56-62"Non-wettable A X X N / Dc Immediately wet A --- X N / D Wettable B --- - < 50 Ligerod B ... ... < 50 Moderate * - B X --- 62 Ligerod B X X N / D Immediately wet B X N / D Wettable to In dines / cm (10"5 newtons / cm) bThe sample was not humid at a higher value, but was wettable at a lower value. Insufficient sample was available to test with Politest surface tension liquids having intermediate values. c Not determined. dLight, non-uniform wettability. eModerate, non-uniform wettability.

The use of fibrinogen and surfactant in the same solution (Solutions B or C did not provide tissues with a uniform wettability of water). The ESCA determinations (not shown) indicated the absence of nitrogen on tissue surfaces, suggesting that tissue fibers were not effectively coated with fibrinogen. The treatment of the tissues with a surfactant after the tissues were coated with protein (Solution A followed by Solution D) produced tissues having a rapid wettability, for example, immediate, similar to that found after heating or aging of tissues Protein coated products produced from polypropylene containing surfactant as a melt additive. So, the wettability of water results from a protein coated surface having a small amount of surfactant present thereon. Significantly, the coating of either the A tissue or the B tissue with fibrinogen followed by the surfactant treatment. produced fabrics having better wettability properties (faster wetting) than Fabrics A and B treated with the surfactant alone.

As noted above, the rate of liquid penetration or the distance at which a fluid moves between the fibers by moisture time to penetrate (moistening) a porous substrate is directly proportional to the liquid surface tension and the cosine of the contact angle of the liquid on the surface of a porous substrate. Because the protein coating significantly increased the surface free energy of the tissue (at about 58 dines / cm or about 58 x 10"s newtons / cm), the surface tension of the aqueous liquid needed only to be decreased by a modest amount in order to result in wettability.However, the surfactant treatment should only decrease the surface tension of the water unless the surface free energy of the polypropylene surface (36 dynes / cm or 36 x 10"5 Newtons / cm) to be wettable, and therefore there is less force or movement of penetration of the liquid by moisture time than with the fabrics of the present invention.

Even though the description has been made in detail with respect to the specific modalities thereof, it will be appreciated by those skilled in the art, upon achieving an understanding of the foregoing, that alterations to, variations of, and equivalents of these can easily be conceived. modalities. Therefore, the scope of the present invention should be established as that of the appended claims and any equivalents thereto.

Claims (47)

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

1. A wettable article comprising an article with a hydrophobic surface, the surface having a coating comprising a surface free energy modifier and a surfactant.

2. The wettable article as claimed in clause 1, characterized in that the hydrophobic surface comprises a hydrophobic polymer.

3. The wettable article as claimed in clause 2, characterized in that the hydrophobic polymer is a polyolefin.

4. The wettable article as claimed in clause 3, characterized in that the hydrophobic polymer is polypropylene.

5. The wettable article as claimed in clause 1, characterized in that the surface free energy modifier is a protein.

6. The wettable article as claimed in clause 5, characterized in that the protein has a weight average molecular weight of at least about 10,000 Daltons.

7. The moisturizable article as claimed in clause 6, characterized in that the protein is selected from the group consisting of fibrinogen, albumin, casein, hemoglobin and lysozyme.

8. The wettable article as claimed in clause 7, characterized in that the protein is a fibrinogen.

9. The wettable article as claimed in clause 7, characterized in that the protein is hemoglobin.

10. The wettable article as claimed in clause 1, characterized in that the surfactant is a polyethoxylated alkylphenol.

11. The wettable article as claimed in clause 1, characterized in that the surface free energy modifier has a surface free energy greater than that of the surface of the article, but less than the surface tension of an aqueous liquid to which the wettable article can be exposed.

12. The wettable article as claimed in clause 1, characterized in that the surfactant is present in an amount effective to lower the tension of the surface of the liquid to a value which is greater than the surface free energy of the surface of the liquid. article and equal to or less than the surface free energy of the surface free energy modifier.

13. The wettable article as claimed in clause 1, characterized in that the article is selected from the group consisting of a film and a fibrous sheet.

14. The wettable article as claimed in clause 13, characterized in that the article is a fibrous sheet.

15. The wettable article as claimed in clause 14, characterized in that the article is a non-woven fabric.

16. A method for preparing a wettable article comprising: forming an article by melt extrusion, at least a portion of which is formed of a polymer composition comprising a hydrophobic polymer and a surfactant adapted to migrate to the surface of the article; Y Cover the surface of the article with a free surface energy modifier.

17. The method as claimed in clause 16, characterized in that the hydrophobic polymer is a polyolefin.

18 The method as claimed in clause 17, characterized in that the hydrophobic polymer is polypropylene.

19. The method as claimed in clause 16, characterized in that the surface free energy modifier is a protein.

20. The method as claimed in clause 19, characterized in that the protein has a weight average molecular weight of at least about 10,000 Daltons.

21. The method as claimed in clause 20, characterized in that the protein is selected from the group consisting of fibrinogen, albumin, casein, hemoglobin and lysozyme.

22. The method as claimed in clause 21, characterized in that the protein is fibrinogen.

23. The method as claimed in clause 21, characterized in that the protein is hemoglobin.

24. The wettable article as claimed in clause 16, characterized in that the surfactant is a polyethoxylated alkylphenol.

25. The method as claimed in clause 16, characterized in that the surfactant migrates to the surface of the article in an amount effective to lower the surface tension of the liquid to a value which is greater than the surface free energy of the liquid. surface of the article and equal to or less than the surface free energy of the surface free energy modifier.

26. The method as claimed in clause 16, characterized in that the article is selected from the group consisting of a film and a fibrous sheet.

27. The method as claimed in clause 26, characterized in that the article is a fibrous sheet.

28. The method as claimed in clause 27, characterized in that the article is a non-woven fabric.

29. A method for preparing a wettable article comprising: forming an article by melt extrusion, wherein the article has a hydrophobic surface; coating the surface of the article with a surface free energy modifier; Y Treat the coated article with a surfactant.

30. The method as claimed in clause 29, characterized in that the hydrophobic surface comprises a hydrophobic polymer.

31. The method as claimed in clause 30, characterized in that the hydrophobic polymer is a polyolefin.

32. The method as claimed in clause 31, characterized in that the hydrophobic polymer is polypropylene.

33. The method as claimed in clause 29, characterized in that the surface free energy modifier is a protein.

34. The method as claimed in clause 33, characterized in that the protein has a weight average molecular weight of at least about 10,000 Daltons.

35. The method as claimed in clause 34, characterized in that the protein is selected from the group consisting of fibrinogen, albumin, casein, hemoglobin, and lysozyme.

36. The method as claimed in clause 35, characterized in that the protein is fibrinogen.

37. The method as claimed in clause 35, characterized in that the protein is hemoglobin.

38. The method as claimed in clause 29, characterized in that the surfactant is a polyethoxylated alkylphenol.

39. The method as claimed in clause 29, characterized in that the surface free energy modifier has a surface free energy greater than that of the surface of the article, but less than the surface tension of an aqueous liquid to which the Wettable item may be exposed.

40. The method as claimed in clause 29, characterized in that the surfactant is present in an amount effective to lower the surface tension of the liquid to a value which is greater than the surface free energy of the surface of the article and equal to or less than the surface free energy of the surface free energy modifier.

41. The method as claimed in clause 29, characterized in that the article is selected from the group consisting of a film and a fibrous sheet.

42. The method as claimed in clause 41, characterized in that the article is * a fibrous sheet.

43. The method as claimed in clause 42, characterized in that the article is a non-woven fabric.

44. A disposable absorbent product, a component of which is the wettable article as claimed in clause 1.

45. A disposable absorbent diaper, a component of which is the wettable article as claimed in clause 1.

46. A disposable absorbent female care product, a component of which is the wettable article as claimed in clause 1.

47. An incontinent and disposable incontinent product, a component of which is the wettable article as claimed in clause 1. SUMMARY A wettable article consisting of an article with a hydrophobic surface having a coating which includes a surface free energy modifier and a surfactant. The hydrophobic surface may include a hydrophobic polymer. The surface free energy modifier has a surface free energy greater than that of the surface of the article, but less than the surface tension of an aqueous liquid to which the wettable coated article can be exposed. The free surface energy modifier is desirably present in an amount sufficient to essentially cover the surface of the article. The surfactant is present in an amount effective to lower the surface tension of the liquid to a value which is greater than the surface free energy of the article surface and equal to or less than the surface free energy of the free energy modifier. Of surface. The article desirably is a film or a fibrous tissue, such as a non-woven fabric. The methods for preparing the wettable article are also described.