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Foam Extrusion Technology and Other Techniques for Production of Absorbent Foam-Fiber Composites

IP.com Disclosure Number: IPCOM000130284D
Publication Date: 2005-Oct-18
Document File: 3 page(s) / 51K

Publishing Venue

The IP.com Prior Art Database

Related People

Jeff Lindsay: AUTHOR [+3]

Related Documents

US6603054: PATENT

Abstract

Foam-fiber composites can be prepared in a variety of ways, including by extrusion. Several such methods are discussed.

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Foam Extrusion Technology and Other Techniques for Production of Absorbent Foam-Fiber Composites

Jeff Lindsay, Fung-Jou Chen, and Sheng Hu

Kimberly-Clark Corporation, Neenah, Wisconsin

Methods for combining fibers and foams into resilient, high-bulk objects are discussed in two recent Kimberly-Clark patents on novel foam-fiber composites, US Pat. No. 6,603,054, "Fibrous Absorbent Material and Methods of Making the Same," issued August 5, 2003, and US Pat. No. 6,261,679, "Fibrous Absorbent Material and Methods of Making the Same," issued July 17, 2001, both in the names of Fung-Jou Chen, J.D. Lindsay, Jian Qin, and Yong Li (hereafter the "Chen patents"). Here we wish to provide related technical details regarding some of the many ways in which fibers can be combined with foams, within the scope of the aforementioned patents.

Several devices and methods described by James L. Thorne in Thermoplastic Foams (Hinckley, Ohio: Sherwood Publishers, 1996) and by S.-T. Lee in Foam Extrusion (Lancaster, Pennsylvania: Technomic Publishing Company, 2000) are believed to be adaptable for some aspects of preparing foam-fiber composites described in the Chen patents. These techniques include extrusion molding techniques such as ring extrusion technology, in which a ring of extruded foam material is extruded around a sizing mandrel that injects air to blow the foam into a larger diameter tube which is then slit to form a web. An example is shown in the figure below, taken from Figure 5.26 of Thorne (p. 206), which shows a sizing mandrel in an extruder.

Other techniques discussed by Thorne include injection molding, expanded bead molding, and foam rotational molding. In adapting foam extrusion or foam molding methods to the Chen patents, cellulosic fibers must be combined with the polymers. This may be accomplished by first combining fibers with resin to form pellets or beads. Alternatively, fibers may be combined with fiber-free pellets or molten resin and blended in a kneader or other mixer to disperse the fibers in the resin prior to extrusion or other forming techniques. The amount of fibers and the fiber length may need to provide suitable rheology for the process in question. Shorter fibers, such as hardwood fibers or chopped rayon flock (e.g., length-weighted average length less than 2 mm) may be useful in some cases to prevent clogging or excessively high viscosity for a given fiber load. Coarser extrusion screws with higher clearances may also be useful in permitting higher fiber loads to be successfully extruded.

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When expanded bead molding is used (related to the process used to generate polystyrene foam cups from individual beads), the fibers may be present initially within the beads or may be blended with the beads prior to expansion of the beads with a swelling agent, or both. This technique may be used to create molded, three-dimension fiber-foam composites. Further in...