Ink-Reinforced Polyurethane Films

The present invention relates to ink-coated thin films and more specifically polyurethane films which are useful in holding I.V. needles in place.

Adhesive materials provided for use on patients, such as for retaining I.V. needles in place, must provide protection against infection, while at the same time allowing epidermal water to evaporate. The material used must therefore allow a rate of moisture vapor transmission which is neither too low nor too high. Previous attempts at such adhesives, such as U.S. Pat. No. Re. 31,887, have provided a continuous backing material of unreinforced polyurethane film combined with a continuous adhesive. Such membranes often allow too much moisture to pass through, are much more likely to break apart, and are more difficult to apply than reinforced materials. It is therefore desirable to obtain a reinforced polyurethane backing material which maintains an optimal rate of moisture vapor transmission and provides more body for ease of application. It is also desirable to obtain other thin films which also have superior strength and tear resistance.

It has been discovered that coating portions of polyurethane or other films with ink provides a product of greater stability and applicability with a moisture vapor transmission rate lower than that of the bare membrane. An ink-coated polyurethane membrane, combined with a suitable adhesive, provides a stronger product which still maintains a sufficient level of moisture transmissability, and is thus a highly desirable material for retaining I.V. needles and the like on the skin.

The ink-coated polyurethane or other membranes of the present invention can also be used in applications not requiring an adhesive. For example, it may be more desirable to wrap an arm or other region with sheets of a non-adhesive thin film material. This film can be reinforced using the method of the present invention yet will not require an adhesive backing.

FIG. 1 is a perspective view of the reinforced polyurethane membrane of the present invention.

FIG. 2 is a top view of the membrane of the present invention having an alternative pattern of ink-type material.

The moisture vapor permeable material of the present invention as observed in FIGS. 1 and 2, comprises a polyurethane backing member coated with an ink-type material. The ink-type material 12 is preferably placed on portions of the polyurethane membrane 10 as in the striped configuration observed in FIG. 1. The ink can be printed in any pattern and can be placed on the top or bottom of the membrane 10. Optimally, the ink-type material covers 1 to 85% of the surface area. The pattern indicated in FIG. 1 allows for greater stability and facilitates the removal of the "wing-type" release liner and subsequent application of the product. This and other ink patterns can reinforce the polyurethane membrane enough to eliminate the need for a frame on the product, as is necessary in prior art membranes. Another configuration of ink-type material on the backing member is observed in FIG. 2.

A number of different ink-type coatings have been used successfully to reinforce the polyurethane backing and still maintain sufficient moisture vapor transmission. Ideally, non-toxic inks along with medically approved colorants can be used. One such coating could be a co-solvent polyamide polymer system ink along with copper-phthalocyanine, a federally approved colorant. Another desirable ink material is styrene dissolved in a carrier such as alcohol or methyl ethyl ketone. It is also possible to employ polyethylene as the ink-type material.

The ink-type material can be applied to the polyurethane membrane in any suitable fashion currently known in the art. For instance, the ink can be applied by conventional printing machines and methods. One such method suitable for depositing the ink on the membrane is known as the gravure flex method of printing. Additionally, the pattern of ink can be placed on the polyurethane by applying it in strips of either hot melt material, or of narrow tape. In all of these ways, a pattern of ink-type material can be placed on the polyurethane, resulting in a strengthened, effective product.

When used with a suitable adhesive, the ink-reinforced membranes of the present invention can be used to retain IV needles and the like in place on the skin of a patient. Such adhesive membranes are constructed by placing a suitable adhesive on the underside of the ink-coated polyurethane backing member by any conventional method. The adhesive used should be porous to allow transmission of moisture through the product or can be of the hydrophilic type such as those used with electrodes. The adhesive can be applied continuously or non-continuously across the backing member, forming any desired pattern which allows for sufficient adhesion to the skin. The resulting product is a strengthened moisture vapor-permeable adhesive suitable for use in retaining IV needles, electrodes, or other devices on the skin of the patient.

The ink-reinforcement process of the present invention is not limited to moisture vapor permeable materials, but can also be used on other thin films which are not moisture vapor-permeable. Ink reinforcement can be applied to a number of moisture vapor-impermeable thin films, such as Saran Wrap, in order to impart further strength, body and tear-resistance to these materials as well. As with the polyurethane membranes, the ink-type materials can be applied in any suitable fashion presently known in the art.