Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2001-12-28
2004-11-02
Tentoni, Leo B. (Department: 1732)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S244240, C156S324000, C264S103000, C264S173150, C264S211180, C264S3420RE, C264S348000
Reexamination Certificate
active
06811638
ABSTRACT:
BACKGROUND OF THE INVENTION
Fibrous non-woven materials and fibrous non-woven composite materials are widely used as products, or as components of products, such as wet-wipes because they can be manufactured inexpensively and made to have specific characteristics. These products can be manufactured so inexpensively that they can be viewed as disposable, as opposed to reusable.
One approach to making fibrous non-woven composite materials for wet-wipes is the use of homogeneous mixtures of materials such as air laid webs of fibers mixed with cellulosic fibers or another absorbent material. Other wet-wipes have been prepared by joining different types of non-woven materials in a laminate or formed as a layered structure. These products can be prepared from plastic materials such as plastic sheets, films and non-woven webs, prepared by extrusion processes such as, for example, slot film extrusion, blown bubble film extrusion, meltblowing of non-woven webs and spinbonding.
The non-woven materials and laminated non-woven materials that are useful for consumer products should meet minimum product standards for strength, moisture level, size, flexibility, thickness, softness and texture. However, if one of these parameters is changed this can affect another of the parameters. Thus, a goal for these laminates is to produce a product that can mimic a soft cloth-like feel or at least get closer to a soft cloth-like feel than has been previously possible while still maintaining acceptable strength.
Such a soft cloth-like feel is often characterized by, among other things, one or more of the following: thickness, bulk density, flexibility, texture, softness, density, and durability of the non-woven materials. These materials are suitable for disposable products such as, for example, disposable diapers, disposable tissues and disposable wipes, for example, disposable wet wipes.
Producing a high quality composite elastic material or Stretch Bonded Laminate (SBL) at a low cost can be difficult. Often the polymers having high elasticity are expensive. It would be advantageous to have a method to provide a high quality SBL and maintain a low cost. In addition it would be advantageous to have a method for controlling the amount of retraction of the SBL. The ability to control the retraction can provide a product having less variability in attributes like basis weight, thickness, stretch to stop, and percent retraction.
Definitions
For the purposes of the present application, the following terms shall have the following meanings:
The term “elastic” as used herein, means any material which, upon application of a biasing force, is stretchable, that is, elongatable at least about 60 percent (i.e., to a stretched, biased length which is at least about 160 percent of its relaxed unbiased length), and which, can recover at least 55 percent of its elongation upon release of the stretching, elongating force. A hypothetical example would be a one (1) cm sample of a material which is elongatable to at least 1.60 cm and which, upon being elongated to 1.60 cm and released, can recover to a length of not more than 1.27 cm. Many elastic materials can be elongated by much more than 60 percent (i.e., much more than 160 percent of their relaxed length), for example, elongated 100 percent or more, and many of these can recover to substantially their initial relaxed length, for example, to within 105 percent of their original relaxed length, upon release of the stretching force.
As used herein, the term “non-elastic” refers to any material which does not fall within the definition of “elastic,” above.
As used herein the term “non-woven web” means a structure or a web of material which has been formed without use of weaving processes to produce a structure of individual fibers or threads which are intermeshed, but not in an identifiable, repeating manner. Non-woven webs have been, in the past, formed by a variety of conventional processes such as, for example, meltblowing processes, spinbonding processes, film aperturing processes and staple fiber carding processes.
The terms “recover” and “recovery” as used herein refer to a contraction of a stretched material upon termination of a biasing force following stretching of the material by application of the biasing force. For example, if a material having a relaxed, unbiased length of one (1) cm is elongated 50 percent by stretching to a length of one and one half (1.5) cm the material would be elongated 50 percent (0.5 cm) and would have a stretched length that is 150 percent of its relaxed length. If this exemplary stretched material contracted, that is recovered to a length of one and one tenth (1.1) cm after release of the biasing and stretching force, the material would have recovered 80 percent (0.4 cm) of its one-half (0.5) cm elongation. Recovery can be expressed as [(maximum stretch length—final sample length)/(maximum stretch length—initial sample length)] times 100.
As used herein, the term “meltblown fibers” means fibers formed by extruding a molten thermoplastic material through a plurality of fine, usually circular, die capillaries as molten threads or filaments into a high velocity gas (e.g. air) stream which attenuates the filaments of molten thermoplastic material to reduce their diameter, which can be to microfiber diameter. Thereafter, the meltblown fibers are carried by the high velocity gas stream and are deposited on a collecting surface to form a web of randomly disbursed meltblown fibers. Such a process is disclosed, for example, in U.S. Pat. No. 3,849,241 to Butin.
As used herein, the term “spunbonded fibers” refers to small diameter fibers which are formed by extruding a molten thermoplastic material as filaments from a plurality of fine, usually circular, capillaries of a spinnerette with the diameter of the extruded filaments then being rapidly reduced as by, for example, eductive drawing or other well-known spun-bonding mechanisms. The production of spun-bonded non-woven webs is illustrated in patents such as, for example, in U.S. Pat. No. 4,340,563 to Appel et al., and U.S. Pat. No. 3,692,618 to Dorschner et al.
As used herein, the term “coform” means a non-woven composite material of air-formed matrix material comprising thermoplastic polymeric meltblown fibers such as, for example, microfibers having an average fiber diameter of less than about 10 microns, and a multiplicity of individualized absorbent fibers such as, for example, wood pulp fibers disposed throughout the matrix of polymer microfibers and engaging at least some of the micro fibers to space the microfibers apart from each other. The absorbent fibers are interconnected by and held captive within the matrix of microfibers by mechanical entanglement of the microfibers with the absorbent fibers, the mechanical entanglement and interconnection of the microfibers and absorbent fibers alone forming a coherent integrated fibrous structure. These materials are prepared according to the descriptions in U.S. Pat. No. 4,100,324 to Anderson et al. U.S. Pat. No. 5,508,102 to Georger et al. and U.S. Pat. No. 5,385,775 to Wright.
As used herein, the term “microfibers” means small diameter fibers having an average diameter not greater than about 100 microns, for example, having an average diameter of from about 0.5 microns to about 50 microns, or more particularly, microfibers may have an average diameter of from about 4 microns to about 40 microns.
As used herein, the term “autogenous bonding” means bonding provided by fusion and/or self-adhesion of fibers and/or filaments without an applied external adhesive or bonding agent. Autogenous bonding can be provided by contact between fibers and/or filaments while at least a portion of the fibers and/or filaments are semi-molten or tacky. Autogenous bonding may also be provided by blending a tackifying resin with the thermoplastic polymers used to form the fibers and/or filaments. Fibers and/or filaments formed from such a blend can be adapted to self-bond with or without the application of pressure and/or heat. Solvents may also be
Baer David J.
Close Kenneth B.
Lange Scott R.
Mattingly Walter A.
Primm Stephen
Kimberly--Clark Worldwide, Inc.
Tentoni Leo B.
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