Dressings and tapes applied to the skin should preferably exhibit a degree of stretchiness so that they do not unduly restrict movement of the underlying skin. This is particularly important in skin areas such as fingers, elbows and knees which are subjected to continuous stretching and relaxation during normal activities. If a tape does not exhibit elastic properties similar to or greater than skin, the tape will exert a force against the skin causing discomfort and in some cases, actual damage to the skin.
The prior art has devised numerous ways of providing elastic tapes and dressings. One popular method is to form loosely woven fabrics containing elastomeric filaments interspersed among non-elastomeric filler yarns. The elastomeric or rubbery filaments provide resiliency to the fabric, i.e., the ability to return to its original size and shape when the stretching force is removed. Typical constructions of this type are described in U.S. Pat. No. 4,207,885 and British Pat. No. 1,449,790. Stretchable knitted fabrics for use in elastic bandages are described in U.S. Pat. Nos. 3,965,703 and 4,173,131. An elastic bandage comprising elastic yarns sealed between two non-woven fibrous webs and between a non-woven fibrous web and a non-porous film are described in U.S. Pat. No. 3,575,782.
The aforementioned elastic fabrics are relatively expensive due, in part, to the elastomeric yarns, which are usually wrapped with non-elastomeric filaments. They are also generally bulky and often puckered in the relaxed state.
Less costly elastic non-woven fabrics of synthetic fibers bonded together at crossover points are described in Belgian Pat. No. 857,077 and Japanese Pat. No. 79040-606.
Dressings and tape backings having elastic properties have also been formed in layered or laminated constructions. European Pat. No. 7-802 describes a synthetic elastomeric fiber sheet made of bonded or non-bonded elastomeric fibers laminated to a less elastic sheet made of natural, synthetic or mineral fibers and/or filaments. British Pat. No. 1,575,830 describes an absorbent dressing such as a diaper comprising an elastomeric film backing laminated to an absorbent material which may comprise paper, wood pulp, or other absorbent material, preferably configured so as to be extensible such as by creping.
U.S. Pat. No. 3,483,018 describes an extensible adhesive tape in which the backing comprises an elastomeric film reinforced with an extensible fibrous substrate such as bias woven gauze having a maximum elongation of from about 20% to about 50%. The properties of the backing are primarily those of the elastomeric film which must be carefully selected to provide the required degree of moisture vapor transmission.