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Molded Three-dimensional Articles Comprising Free-flowing Fibrous Particles ("Nits")

IP.com Disclosure Number: IPCOM000129989D
Publication Date: 2005-Oct-07
Document File: 5 page(s) / 309K

Publishing Venue

The IP.com Prior Art Database

Related People

Jeffrey D. Lindsay: AUTHOR [+3]

Related Documents

US 5,800,417: PATENT [+3]

Abstract

Free-flowing bundles of cellulose fibers, somtimes called "nits," can be used in combination with resins or other binders to form three-dimensional molded objects. The light weight and low cost of nits can offer benefits to such products, in addition to contributing other desirable properties.

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Molded Three-dimensional Articles Comprising Free-flowing Fibrous Particles ("Nits")

Jeffrey D. Lindsay, Fung-Jou Chen, and Jim Tanner

Kimberly-Clark Corporation, Neenah, Wisconsin

Introduction

Free flowing fibrous particles, often called "nits" or fibrous bundles, have been disclosed for use in absorbent articles such as sanitary napkins (see the following K-C patents: US 5,800,417; 6,562,192; and 6,667,424). These particles can be made by high consistency mechanical treatment (e.g., kneading) of eucalyptus fibers or other cellulosic fibers. They have been proposed for use as free-flowing materials in absorbent articles. Photomicrograph of eucalyptus nits are shown in Figures 1 and 2 below.

Figure 1. Photomicrograph of a eucalyptus nit.

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Figure 2. Cross-section of a eucalyptus nit viewed with SEM.

Now we propose that nits coupled with binder fibers or other binder material can be analogous to expanded polystyrene beads (available from Huntsman Expandable Polymers, Peru, IL) that are molded into various shapes such as foam cups using bead molding techniques or other known foam molding methods. The concept is that nits can be used to make a wide variety of low-cost, lightweight, and optionally absorbent three-dimensional materials by filling a volume with free flowing nits and activating binding means to join the discrete nits into a molded article. In one version, the nits are combined with a foamable or swellable agent that can fill at least some of the voids between nits and, after curing or solidifying, provide a matrix of a binding agent between the nits.

Such methods can be used to produce a wide variety of light-weight and low-cost objects, such as food trays, egg cartons, landscaping materials, cushions, packaging materials, mats and pads, absorbent articles, and so forth.

Details

The binding means typically comprises thermoplastic material which is thermally fused to join the nits together. The thermoplastic material can take several forms, including:

* Thermoplastic binder fibers (e.g., bicomponent fibers in any configuration such as sheath-core, side-by-side, pie segments, etc.) that are combined with the cellulosic fibers during or prior to the mechanical treatments that produce nits;

* Binder fibers that are blended with pre-existing nits;

* Binder fibers that are joined to the surface of nits (e.g., electrostatic coating, coating in a fluidized bed such as the Wurster devices described in US Pat. No. 6,740,406, "Coated Activated Carbon," issued May 25, 2004 to S. Hu, R. Edens, J.D. Lindsay, and T.G. Shannon, etc.), preferably in a way that maintains a degree of flowability of the treated nits;

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* Binder particles such as fine dust of thermoplastic material that is combined with existing nits, such as adhering the binder particles to the surfaces of nits;

* Binder material that is applie...