Stock material or miscellaneous articles – Structurally defined web or sheet – Discontinuous or differential coating – impregnation or bond
Reexamination Certificate
1999-11-16
2003-10-28
Morris, Terrel (Department: 1771)
Stock material or miscellaneous articles
Structurally defined web or sheet
Discontinuous or differential coating, impregnation or bond
C428S200000, C428S201000, C428S339000, C428S095000, C442S381000, C442S409000, C156S291000, C604S358000, C604S380000
Reexamination Certificate
active
06638605
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to new and improved disposable nonwoven laminates and new and improved methods for making them, as well as, to new and improved surgical drapes and gowns comprising the new and improved disposable nonwoven laminate materials. More particularly, it relates to new and improved disposable multi-ply surgical laminates including nonwoven layers in which plies of the laminate are bonded in a special flexible manner to provide materials having improved softness, hand and drapability and in which the desired material properties of layers are better retained and expressed to provide more satisfactory products.
Surgical drapes and gowns have been used to maintain a sterile field in surgery. Surgical gowns have been used in the medical community to protect health care professionals from liquids and micro-organisms during surgical and other procedures. Single use surgical gowns are typically made of nonwoven, disposable fabrics. Such gowns typically include a single body panel or multiple panels including a front panel, a pair of back panels which are connected to the sides of the front panel and extend away from the front panel, and a pair of sleeves which are provided at the juncture of the front and side panels. The front panel covers the front of the health care professional during the procedure. The back panels are secured around and overlap each other to cover the rear of the health care professional and a tying structure. Typical surgical gowns will include two outer ties and two inner ties. The inner ties are utilized to secure the inside back of the gown. The outer ties are used to ensure that the back of the gown overlaps around the rear of the health care professional.
Sterile surgical drapes are also known and widely used to create a sterile surgical field and to protect the patient. Surgical drapes come in a variety of shapes and sizes and many specialized drapes adapted for a particular type of surgery have been adopted. By way of illustration, these drapes may be provided in a rectangular sheet form for draping the operating table, covering an anesthesia procedure area, or covering the patient's legs or abdomen. More specialized drapes may include leg holes or arm holes as required for different procedures so that some portions of the patient's body remain unexposed under the drape and other portions are exposed overlying a different section of the drape. Some drapes are provided with openings or windows called fenestrations to define a bounded area around an incision site. Fenestrated drapes may have extra absorbent layers around the perimeter of the openings. Surface treatments may be used to render portions of the drapes antibacterial, antimicrobial, and/or waterproof as desired in particular surgical procedures. Simple rectangular drapes may also be used as absorbent surgical towels or wipes. Finally, the drapes may include different types of panels secured together. For example, a table drape may include a thicker absorbent table top panel and a plurality of attached side panels which have a thinner less absorbent construction to act simply as a splash guard for or to provide a barrier with respect to the underside portions of the table.
Earlier surgical drapes and gowns were constructed of woven natural fabric materials, usually cotton. These cloth articles were sterilized in the autoclave in preparation for surgery. Alternative fabrics comprising synthetic fibers were added and used. Eventually, with the advent of nonwoven fabric materials, drapes and gowns comprising nonwovens were used to provide disposable gowns and drapes adapted for one time use.
Previous drapes and gowns prepared from nonwoven materials suffer from a number of drawbacks. Typically, the nonwoven web layers are assembled with a film layer to provide a fluid impervious laminate material which is used to fashion the surgical gown. Hot melt adhesives have generally been applied over substantially the entire surface of one of the layers to bond the web and film layers together to provide the laminates. These laminates are characterized by board-like stiffness and poor drapability which makes them uncomfortable for the medical personnel who wear them. Sleeves made from these fabrics do not conform well to the wearer's wrist and frequently permit body fluids to travel along crinkled channels at the wrist under the glove cuffs and against the wearer's skin which is unacceptable. Moreover, the films used to provide an effective fluid barrier, are generally not breatheable and accordingly, gowns made from these laminates can be unbearably hot for the surgical personnel who must wear them.
Efforts to improve the softness and cloth-like quality of these nonwoven surgical laminates has lead some manufacturers to try intermittent thermal bonding of the layers through heat and pressure rollers, or ultrasonic welding techniques. The heat and pressure bonded types are undesirable because the nonwoven layers are crushed and fused in the process which detracts from their desired properties such as loft, flexibility and softness. The melt bonding points are rigid and do not bend and flex, so that the overall softness, feel and drapability properties of these materials is better but still not as good as desired. Moreover, heat bonded laminates may only be formed from appropriately heat matched thermoplastic materials, which limits the types of material layers that can be used to form the surgical laminates, placing unwanted limits on product design and ultimate product qualities.
SUMMARY OF THE INVENTION
Unexpectedly, in view of the foregoing, it has now been discovered that new and improved disposable nonwoven surgical laminates may be provided using dramatically reduced amounts of adhesive arrayed in a special bonding arrangement to provide improved disposable nonwoven surgical laminates having improved softness, hand, drapability, and comfort characteristics. In greater detail and in accordance with an embodiment of the present invention, a new and improved disposable laminate comprises a film layer, at least one nonwoven web layer and a plurality of spaced apart unbounded adhesive clusters. Each adhesive cluster comprises a plurality of discrete, spaced apart droplets of adhesive securing the film layer and the web layer together. Preferably, the adhesive clusters are spaced in a regular repeating pattern which extends the length and width of the laminate.
By unbounded is meant that the adhesive clusters do not include any applied linear boundary or perimeter of adhesive defining the cluster area. Each cluster is a perimeterless grouping of spaced apart droplets. Each cluster area is flexibly foldable in all directions with respect to the plane of the laminate which is believed to contribute to superior hand and drapability for the new and improved laminates. The low adhesive content and flexible bonding methods permit the overall softness and other desired web properties, such as absorbency, to be maintained in the laminating process and to be retained and more fully expressed in the finished laminates and products.
The film layers are preferably thermoplastic materials capable of withstanding gamma sterilization. Preferably, the thermoplastic film layers form a satisfactory fluid impervious layer capable of preventing fluid and pathogen transfer between surgical personnel and patient through the laminate. The films may be breatheable or non-breatheable. Illustrative thermoplastic films which may be used to provide the film layer include polyolefins, polyolefinic copolymers, polyesters and copolyesters to name but a few. The thermoplastic films may be made from substantially any film forming thermoplastic material suitable for close to the skin use which may withstand commercial sterilization procedures.
In a preferred embodiment, the thermoplastic film layers comprise breatheable impervious thermoplastic films selected from monolithic thermoplastic films or microporous thermoplastic films. Especially preferred films are mo
Ankuda, Jr. Edward J.
Miller Joe
Swanberg Daniel L.
Thompson Eric S.
Allegiance Corporation
Guarriello John J.
Morris Terrel
Rozycki Andrew G.
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