Surgery: splint – brace – or bandage – Bandage structure – Skin laceration or wound cover
Reexamination Certificate
2001-01-26
2002-09-10
Brown, Michael A. (Department: 3764)
Surgery: splint, brace, or bandage
Bandage structure
Skin laceration or wound cover
C602S043000, C602S042000, C602S041000
Reexamination Certificate
active
06448462
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a medical bandaging material.
2. Description of Related Art
Depending on the size and kind of the wound or injury, plasters with and without pads, compresses or bandages are used for medical bandaging materials. In such an application, the materials used to promote the healing process must not have any barrier effect against water vapor or the gases liberated by the healing process, such as carbon dioxide. In particular, in addition to having a high resistance to abrasion, plasters are expected to have a surface which repels dirt and has high tactility, i.e. has a nubuk leather kind of touch, as well as being free of splits and of fuzz.
From the documents U.S. Pat. No. 4,630,603, U.S. Pat. No. 4,950,282, U.S. Pat. No. 5,011,492 and U.S. Pat. No. 5,679,190 medical bandaging materials are known whose backing material is made of a nonwoven fabric. These materials have the problem, especially when they are coated with a pressure sensitive adhesive with great adhesive strength to human skin, that they tend to having the nonwoven fabric layers delaminate or the fibers leach out. This would make taking them off more difficult when changing bandages.
SUMMARY OF THE INVENTION
The object of the present invention is to set forth a medical bandaging material having high resistance to abrasion, low soilability, a high tactility, suppleness and adaptability to body shapes and movements, high gas and water vapor permeability, as well as no tendency to nonwoven fabric layer splitting.
DETAILED DESCRIPTION OF THE INVENTION
According to the present invention, the object is attained by using a medical bandaging material made of a microfilament nonwoven material with a mass per unit area of 30 to 150 g/m2 and a tear strength of >40 N/5 cm, the nonwoven fabric consisting of continuous multicomponent filaments with a titer of 1.5 to 5 dtex which are melt-spun, stretched and directly laid down to form nonwoven fabric, and the continuous multicomponent filaments, if necessary after prebonding, being, at least to the extent of 80%, split and bonded to continuous microfilaments with a titer of 0.01 to 1.0 dtex. The medical bandaging materials do not show nonwoven fabric layer delamination, and have water vapor permeability of at least 400 g/m2 and per 24 h.
The medical bandaging material is preferably one in which the nonwoven fabric has a mass per unit area of 40 to 120 g/m2 and consists of continuous multicomponent filaments with a titer of 1.5 to 3 dtex, which are melt-spun, aerodynamically stretched and directly laid down to form a nonwoven fabric, and the continuous multicomponent filaments, if necessary after prebonding, being, at least to the extent of 80%, split and bonded to continuous microfilaments with a titer of 0.05 to 0.5.
Furthermore, a particularly advantageous medical bandaging material is one in which the continuous multicomponent filament is a continuous bicomponent filament, consisting of two incompatible polymers. Such a continuous bicomponent filament is composed of polyesters, such as polyethylene terephthalate, polybutylene terephthalate or polytetramethylene teraphthalate together with a polymer incompatible with these, such as polypropylene, polyethylene, polyamide 6, polyamide 6.6, or a thermoplastic elastomer (TPE). For extremely soft, nonelastic bandaging materials, a nonelastic polymer and a TPE are used for the polymer pairing, as, for instance, a polyester elastomer and a polyamide 6.6. For extremely soft, highly stretchable elastic medical bandaging materials, a polymer pairing of two thermoplastic elastomers is used, as, for instance, a polyester elastomer with a styrene-butadiene-styrene block copolymer. Furthermore, for rigid, not very stretchable medical bandaging materials, a polymer combination of nonelastic polymers, so-called thermoplastic nonelastomers (TPNE) and thermoplastic elastomers is produced. In the polymer pairing TPNE/TPE, the lower melting, or rather lower softening component is used to produce at least partial-surface connections of the filaments of the higher melting component. The difference in melting point or adhesion temperature between TPNE and TPE is at least 10° C., and preferably at least 30° C. For the binding procedure, known methods such as directed or circulating hot air currents, hot calendering or ultrasound welding can be used.
Especially advantageous also is a medical bandaging material in which the continuous multicomponent filaments have a cross-section with an orange-like multisegment structure, the segments, in alternating sequence, each including one of the two incompatible polymers and/or a “side-by-side” structure. The medical bandaging material has a high water vapor permeability index as well as a humidity absorption capacity, so that, if necessary, one can do without the pad when using it as a plaster. The lower or upper sides of the medical dressing do not have to have the same resistance to mechanical abrasion in a dry or damp condition. To improve the resistance to abrasion and to achieve a superficially foil-like surface of the upper side, which furthermore has a microporous structure, the medical bandaging material is bonded and smoothed off by being pressed against a smooth, heated roll.
In addition, the medical bandaging material is one in which the two sides of the bandaging material have a different segment structure. This raises the absorption capability of the bandaging material. The absorption capability can also be improved by a different degree of entanglement of the fibers among one another. For this, water jet bonding is performed on the upper and lower side of the medical bandaging material with different pressures, so that a greater integrity of the upper and lower sides comes about. However, the intensity of entanglement, even at the weakest cross-sectional regions, is so strong, that delamination nonwoven fabric layers under wet or dry conditions is completely prevented. For use of the bandaging material as a plaster, the underside, on which the adhesion material layer is applied, is preferably not smoothed off, since a little roughness makes for better anchoring of the adhesive material. The continuous bicomponent filaments of the medical bandaging materials, before splitting, can also be treated by crimping, with methods known per se, with the crimping possibly being two-dimensionally flat, e.g. zigzag-shaped or spiral-shaped.
Especially advantageous is a medical bandaging material, in which at least one of the incompatible polymers, forming the continuous multicomponent filaments, contains amounts up to 10% by weight of additives such as dyestuffs, permanently acting antistatics, fungicides, bactericides, softeners, stabilizers, wetting and parting agents, optical brightening agents, additives influencing spinning character or melt fusion, as the case may be, and/or additives influencing hydrophilic or hydrophobic properties. Depending on the type of application, the specific requirements can thus be fulfilled. Medically effective additives are chosen for this in such a way that they migrate to the fiber surface, either immediately after being extruded or after storage, and there become more concentrated as well as capable of being given off to the surroundings. The additives influencing the physical properties of the fibers are preferably chosen so as to be statistically distributed constantly in time over the entire microfiber cross-section.
The method for producing a medical bandaging material preferably provides that the continuous multicomponent filaments are melt-spun, stretched and directly laid down to form nonwoven fabric, a prebonding process is optionally carried out and the nonwoven fabric is bonded by the use of high pressure fluid jets, and at the same time split into continuous microfilaments with a titer of 0.01 to 1.0 dtex. Medical bandaging materials produced in this manner have a soft touch, high resistance to abrasion, and a water vapor permeability of at least 400 g/m2 and per 24 h, but pr
Groitzsch Dieter
Schaut Gerhard
Brown Michael A.
Firma Carl Freudenberg
Hamilton Lalita M
Kenyon & Kenyon
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