Surgery – Means and methods for collecting body fluids or waste material – Absorbent pad for external or internal application and...
Reexamination Certificate
1998-10-02
2001-11-27
Weiss, John G. (Department: 3761)
Surgery
Means and methods for collecting body fluids or waste material
Absorbent pad for external or internal application and...
C604S385240, C604S373000, C604S385270
Reexamination Certificate
active
06323389
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to composite elastic materials produced from polymers whose number and/or weight average molecular weight is characterized as the entanglement molecular weight, which is also a function of the microstructure of the polymer in a continuous filament stretch bonded laminate process. More particularly, the present invention relates to a nonwoven laminate of continuous filaments bonded to a meltblown layer, both of these layers being stretched and bonded between two layers of spunbonded material, the resulting web being relaxed prior to being wound on a takeup roll. The material is useful as side panels in training pants, and other articles where elastic material capable of prolonged performance at body temperature.
BACKGROUND
A key aspect of a disposable garment is fit over time at use temperature, i.e., the body temperature. Therefore, elastic properties are measured at body temperature to simulate the expected end use conditions. Such garments often include portions which are subject to repeated stretch and relaxation stresses over an extended period of time. Examples include garment materials, pads, wound dressings and wraps, diapers and personal care products where elasticity may be desired. A particular example is the side panel of training pants and incontinence undergarments. This side panel is typically made of an elastic material, often a composite, which can withstand the repeated stretch and resulting stress at body temperature.
At body temperature certain elastic properties of polymers become important. Two specific elastic properties measured are the rate of load decay and the load loss observed over a period of twelve hours at body temperature.
A conventional method of forming such elastic composite material is one in which nonelastic spunbond facing materials are combined with an elastomer layer, comprised of high performance elastic strands. The laminate of the elastic strands is made by; bonding the strand to the facings using a meltblown polymer containing a tackifier and/or a pressure sensitive adhesive. This produces a nonwoven elastic composite with desirable elongations, along with improved mechanical and body conformance properties. This process is sometimes known as a continuous filament stretch bonded laminate (“CFSBL”) process.
SUMMARY OF THE INVENTION
The present invention comprises a continuous feed spun bonded laminate having improved elastic properties measured at body temperature. In a preferred embodiment the laminate comprises a layer of filaments formed by a continuous filament process, to which is bonded a layer of meltblown fibers. This composite material is then sandwiched between two layers of spunbond fibers after being stretched. The resulting layers are then passed between a pair of niprolls and the resulting laminate is then relaxed prior to winding on a takeup roll.
A unique feature of the present invention is the incorporation of a triblock copolymer as the filament layer. The triblock polymer is preferably of a triblock polystyrene-poly(ethylene/propylene)-polystyrene (“SEPS”) copolymer or a polystyrene-poly(ethylene/butylene)-polystyrene (“SEBS”) copolymer, each having a number average molecular weight of about 81,000 g/mol. The weight percent of styrene is approximately 18% and the weight percent of ethylene/propylene is approximately 82%. Conventional triblock polymer is typically in the 61,000 g/mol range. The molecular weight increase in the polymer midblock, while holding the molecular weight of the styrene block constant, increases the entanglement density, polymer chain persistence length and the relaxation time. The resulting laminate load decay rate and load loss measurements over a period of 12 hours at body temperature showed marked improvement over known CFSBL product. The laminate is particularly useful as side panel material in training pants because of the resistance to sagging at body temperature.
REFERENCES:
patent: 4100324 (1978-07-01), Anderson et al.
patent: 4107364 (1978-08-01), Sisson
patent: 4209563 (1980-06-01), Sisson
patent: 4515854 (1985-05-01), Kogame et al.
patent: 4543099 (1985-09-01), Bunnelle et al.
patent: 4663220 (1987-05-01), Wisneski et al.
patent: 4692371 (1987-09-01), Morman et al.
patent: 4707398 (1987-11-01), Boggs
patent: 4720415 (1988-01-01), Vander Wielen et al.
patent: 4734311 (1988-03-01), Sokolowski
patent: 4741949 (1988-05-01), Morman et al.
patent: 4753843 (1988-06-01), Cook et al.
patent: 4777080 (1988-10-01), Harris, Jr. et al.
patent: 4789699 (1988-12-01), Kieffer et al.
patent: 4803117 (1989-02-01), Daponte
patent: 4818597 (1989-04-01), Daponte et al.
patent: 4879170 (1989-11-01), Radwanski et al.
patent: 4923742 (1990-05-01), Killian et al.
patent: 4939016 (1990-07-01), Radwanski et al.
patent: 4981747 (1991-01-01), Morman
patent: 5169706 (1992-12-01), Collier, IV et al.
patent: 5238733 (1993-08-01), Joseph et al.
patent: 5260126 (1993-11-01), Collier et al.
patent: 5292582 (1994-03-01), Gibbs et al.
patent: 5304599 (1994-04-01), Himes
patent: 5324580 (1994-06-01), Allan et al.
patent: 5332613 (1994-07-01), Taylor et al.
patent: 5334446 (1994-08-01), Quantrille et al.
patent: 5336545 (1994-08-01), Morman
patent: 5366786 (1994-11-01), Connor et al.
patent: 5366793 (1994-11-01), Fitts, Jr. et al.
patent: 5385775 (1995-01-01), Wright
patent: 5415925 (1995-05-01), Austin et al.
patent: 5425987 (1995-06-01), Shawver et al.
patent: 5470639 (1995-11-01), Gessner et al.
patent: 5512358 (1996-04-01), Shawver et al.
patent: 5536563 (1996-07-01), Shah et al.
patent: 5549964 (1996-08-01), Shohji et al.
patent: 5582903 (1996-12-01), Levy et al.
patent: 5630844 (1997-05-01), Dogan et al.
patent: 5635290 (1997-06-01), Stopper et al.
patent: 0548609 (1993-06-01), None
patent: 0546837 (1993-06-01), None
patent: 9720091 (1997-06-01), None
Kraton® Polymers and Compounds: Typical Properties Guide, Shell Chemical Company, 1996.
Fitts, Jr. James R.
Shane Richard M.
Thomas Oomman P.
Willitts Donald V.
Bernstein Jason A.
Bernstein & Associates P.C.
Kimberly--Clark Worldwide, Inc.
Shanoski Paul
Weiss John G.
LandOfFree
High performance elastic composite materials made from high... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with High performance elastic composite materials made from high..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and High performance elastic composite materials made from high... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2618412