US 20060292951A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2006/0292951 A1 Dutkiewicz et al. (43) Pub. Date: Dec. 28, 2006 (54) FIBERS OF VARIABLE WETTABILITY AND Related U.S. Application Data MATERALS CONTAINING THE FIBERS (63) Continuation of application No. PCT/US04/43030, filed on Dec. 20, 2004. (75) Inventors: Jacek K. Dutkiewicz, Cordova, TN (60) Provisional application No. 60/531,706, filed on Dec. (US); Stephen A. Skirius, Collierville, 19, 2003. Provisional application No. 60/569,980, TN (US): Sonja McNeil Fields, filed on May 10, 2004. Memphis, TN (US); Lynn Hung Publication Classification Rushing, Olive Branch, MS (US); David Jay Smith, Germantown, TN (51) Int. Cl. (US); Michael Kalmon, Boyertown, PA D6M I3/00 (2006.01) (US); Ronald Timothy Moose, (52) U.S. Cl. ................................................................ 442/79 Lakeland, TN (US); Ryszard Fryczkowski, Bielsko-Biala (PL); (57) ABSTRACT Beata Fryczkowska, Bielsko-Biala The present invention is directed to an absorbent material (PL); Monika Rom, Bielsko-Biala (PL) and the fibers therein, having two or more layers including Correspondence Address: an upper Surface layer which has on the outer Surface of the BAKER BOTTS, L.L.P. layer one or more surface area Zones which are more 30 ROCKEFELLER PLAZA wettable Zones and adjacent thereto one or more less wet table Zones, where the more wettable Zones have a greater NEW YORK, NY 10112-4498 (US) hydrophilicity than the less wettable Zone. The present (73) Assignee: BKI Holding Corporation invention is also directed to the fibers therein, which contain polyvalent cation-containing compounds and fatty acid con (21) Appl. No.: 11/471,040 taining compounds. The present invention also provides for methods of treating fibers or Solid materials and processes of (22) Filed: Jun. 19, 2006 producing the hydrophobic materials. Patent Application Publication Dec. 28, 2006 Sheet 1 of 10 US 2006/0292951 A1 i . Figure 1C Patent Application Publication Dec. 28, 2006 Sheet 2 of 10 US 2006/0292951 A1 Patent Application Publication Dec. 28, 2006 Sheet 3 of 10 US 2006/0292951 A1 Figure 3A Figure 3B Patent Application Publication Dec. 28, 2006 Sheet 4 of 10 US 2006/0292951 A1 Figure 4A Figure 4B Patent Application Publication Dec. 28, 2006 Sheet 5 of 10 US 2006/0292951A1 9 O 29.7 CIn Figure 5A w 29.7 cm Figure 5B Patent Application Publication Dec. 28, 2006 Sheet 6 of 10 US 2006/0292951 A1 11 Figure 6 Patent Application Publication Dec. 28, 2006 Sheet 7 of 10 US 2006/0292951 A1 Figure 7 Patent Application Publication Dec. 28, 2006 Sheet 8 of 10 US 2006/0292.951 A1 Patent Application Publication Dec. 28, 2006 Sheet 9 of 10 US 2006/0292.951 A1 13 Patent Application Publication Dec. 28, 2006 Sheet 10 of 10 US 2006/0292951 A1 P90 hydrophobic surface hydrophilic surface FIGURE 11 120 | |- > - 110 T -- N--Ricinoleic acid 100 1. 1. -- -O-Linoleic acid g 1. + -A- Oleic acid C 90 -- - NI-V-Lauric acid w - orm N -0-Walpro wh- -- -(-Palmitic acid 5 - ur-. O 80 --2RS-D- Stearic acid 70 60 O 1000 2000 3OOO 4000 5000 6000 7000 8000 Total Content Appm) FIGURE 12 US 2006/0292951 A1 Dec. 28, 2006 FIBERS OF VARIABLE WETTABILITY AND 0012 From the equation, barrier quality is predicted to be MATERALS CONTAINING THE FIBERS enhanced by reducing the size of the interfiber pores. Ideally, the web should be as strong as possible. As pressure builds, FIELD OF THE INVENTION weakness in the web will cause deformation, and deforma tion increases r, thus lowering pressure P. Web strength can 0001. The present invention is directed to an absorbent be enhanced, for example, by increasing the amount of material, and the fibers therein, having variable wettability binder in the web. for the control of water absorption on the surface of the material. 0013 The size of interfiber pores in a fibrous web is determined by the fiber size and the density or extent of BACKGROUND OF THE INVENTION compaction of the web. Increasing the density of the web can reduce the size of interfiber pores, or using Smaller 0002. It has long been desirable to be able to control the diameter fibers at the same density can reduce them. Smaller Surface characteristics of textiles and fabrics including non fibers pack together more efficiently in a densified web, woven materials. A particularly important characteristic is resulting in Smaller interfiber pores. From the equation, whether a material readily absorbs or repels water at its using Smaller fibers serves to decrease r, thus raising pres surface. For fibers used to make nonwoven materials for use Sure P. in personal care products and for many other uses, the 0014 Filler material can be added to an absorbent mate relative hydrophobicity or hydrophilicity of the fiber itself, rial to reduce the size of interfiber pores. From the equation, and the material made from it, is of great importance in the addition of filler also serves to decrease r, thus raising determining where and how they can be used. pressure P. 0003. When brought into contact with the surface of a 0015. From the equation, hydrophobicity and barrier material, water prefers to wet some Surfaces and prefers to quality is predicted to be directly proportional to the fluid bead on others. A Surface can be classified as hydrophilic, surface tension. The barrier treatment should be as durable with a water contact angle less than 90°, or hydrophobic, as possible. Any additives in the barrier treatment that will with a water contact angle greater than 90°, based on the dissolve in the fluid coming in contact with the surface of the shape that a drop of water assumes when placed on that material will likely lower its surface tension, thus lowering Surface. pressure P. 0004 Fabric water repellency and breathability have been studied for several decades (A. W. Adamson, Physical SUMMARY OF THE INVENTION Chemistry of Surfaces, Second Edition, Wiley, 1967, Chap 0016. The present invention provides for an absorbent ters VII and X). A nonwoven web of fibers can be modeled material with two or more layers, including an upper layer as a bundle of cylindrical pores (capillaries) of radius r. The which has on the outer Surface one or more surface area fluid pressure required to penetrate the interfiber pores of a Zones. These Zones include more wettable Zones having nonwoven web can be approximated from Laplace's equa greater hydrophilicity adjacent to less wettable Zones. The tion for the penetration of a fluid into a tube as follows: P=(2 treatment of the fibers in the absorbent material allow for the Y cos 0)/r variable wettability of the present invention. where: 0017. In certain aspects of the invention, the absorbent materials have more wettable Zones with a total surface area 0005 P=pressure required to push fluid through the tube: which is from about 5 percent to about 95 percent of the upper Surface layer. In a preferred embodiment, the more 0006 y=fluid surface tension; wettable Zones have a total surface area which is from about 0007 0=advancing contact angle; and 10 percent to about 90 percent of the upper surface layer, even more preferred, from about 30 percent to about 70 0008 r=pore radius. percent of the upper Surface layer. 0009. See Dutkiewicz, J., Nonwoven Structures for 0018. In another aspect of the invention, the more wet Absorption of Body Fluids, sub-chapter 2.1. Basic Structural table Zones of the absorbent material have elements in a Properties of Absorbent Networks, pages 7-37 (published by pattern which are all connected, the elements of the pattern Edana, Brussels, Belgium) (2003). This equation can be essentially isolating the less wettable Zones from each other. used to describe web wetting (0.<90°, P is positive) or web Likewise, in another aspect of the invention, the less wet water repellency (0-90°, P is negative). In the case of water table Zones have elements in a pattern which are all con repellency, the fluid will not wet the web unless a pressure nected, the elements of the pattern essentially isolating the of P is applied to push the fluid into the web. more wettable Zones from each other. 0010 From the equation, barrier quality is predicted to be 0019. In the absorbent material of the present invention, enhanced by increasing the contact angle with a water the less wettable Zones of the upper Surface layer contain a repellent finish. In other words, the pores of the web should polyvalent metal ion salt of a fatty acid. In one embodiment be rendered as hydrophobic as possible. of the invention, the more wettable Zones of the absorbent 0011 Apparent contact angles can be increased by Sur material contain a polyvalent metal ion salt of a fatty acid face roughness on the macroscale and microscale. Applica and where the concentration of the polyvalent metal ion salt tion of a waterproofing agent that causes microscopic pore of a fatty acid is greater in the less wettable Zones. Surface roughness will lead to an increase in apparent 0020. The present invention also provides for absorbent contact angle, thus improving barrier quality. materials where the less wettable Zones of the upper surface US 2006/0292951 A1 Dec. 28, 2006 layer are located on protrusions which project above the ments, the carrier may be a type of fibers, preferably a surface of the material and the more wettable Zones are polypropylene fiber. In one embodiment, the carrier com located in indentations which project below the surface of prises an acid. In a specific embodiment, the acid is Stearic the material.