Plastic and nonmetallic article shaping or treating: processes – With step of making mold or mold shaping – per se – Utilizing surface to be reproduced as an impression pattern
Reexamination Certificate
1999-06-30
2002-05-07
McDowell, Suzanne E. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
With step of making mold or mold shaping, per se
Utilizing surface to be reproduced as an impression pattern
C264S303000, C264S304000, C264S317000, C264S338000
Reexamination Certificate
active
06383434
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to methods of making shaped structures with an overcoat layer. The present invention also relates to making polymeric structures such as cannulas and catheters. In addition, the present invention also relates to urinary catheters and most particularly to female urinary catheters.
BACKGROUND OF THE INVENTION
Many structures, for example, hoses, condoms, gloves, cannulas, catheters, and the like, are made of a polymeric material (e.g., latex, silicone). Such polymeric structures may have various shapes, e.g., sections with different diameters, contours, etc. In addition, various cavities might be present in the structures, some of which might contain fluids of various types. A traditional way to form such structures is by adhesively affixing parts together so that the outer coat can attain the desired shape. However, these traditional methods do not lend themselves to mass production and are labor intensive. Some shapes are extremely difficult if not impossible to make by traditional adhesive methods. Likewise, traditional methods of making shaped structures of nonpolymeric substances, such as inorganic materials, with cavities therein sometimes have similar difficulties.
An example of a shaped polymeric structure is a catheter. Most catheters are cannulas or tube like devices which are inserted into a portion of a person's body in order to transport fluids, such as liquids, gases, and sometimes semisolid material, in or out of that particular portion of the body. For instances, urinary catheters are used to transport urine collected in the bladder out of the body via the urinary tract. Other types of catheters such as gastronomy devices, transport fluids into and out of various segments of the gastrointestinal system, primarily the stomach.
In order to provide a means of retaining the catheter within the body, inflatable bag catheters were introduced many years ago. Subsequently, Foley (U.S. Pat. No. 3,409,016) taught an elongated catheter having a secondary lumen for inflating a retention balloon at a distal end of the catheter once the distal end is positioned within the body. Generally, the “distal end” is the end of the catheter that is first introduced into the body when the catheter is being positioned within the body and the “proximal end” is the end opposite the distal end. Such catheters are now generally referred to as “Foley” catheters out of respect for the contribution made by Dr. Foley. Because of the variation in needs of patients, improvements on Dr. Foley's contribution to the catheter art are continually being made. These improvements sometimes result in cannulas or catheters that have shapes quite different from that of the device originally designed by Dr. Foley.
Traditionally, Foley catheters are made by a process which includes slipping a band of cured rubber over a double lumen latex rubber tubing and affixing the band on the double lumen tubing by dipping the band and the tubing in a suspension of latex to form an outer layer. The cost of manufacturing traditional Foley catheters has been influenced by the need to use a significant amount of hand labor to make the devices, especially the silicone rubber Foley catheters. Moreover, in many cases where a polymeric structure such as a catheter is to have a cavity filled with fluid, traditional manufacturing methods can not be used. It will be appreciated that using such traditional methods to make catheters that have a variety of shapes and sizes of cavities between the tubing and the outer layer would add significantly to the cost of production and pose limitations on the variety of catheters that can be made. Reducing the amount of hand labor in the manufacture of such devices may reduce the cost of such devices so as to provide a more affordable product to the consumer and to render such a product more competitive in the market place.
The same problem of high labor cost and limitation of the variety of shapes is similarly encountered in the manufacture of other shaped structures such as gastronomy devices, condom, and hoses. The present invention provides a method of making polymeric structures which offers substantial advantages over traditional manufacturing methods. In addition, the present invention provides a simple, easily applied, comfortable disposable catheter for incontinent females.
SUMMARY OF THE INVENTION
Method of Making Polymeric Structures
The present invention relates to making a shaped structure by coating at least a portion of a shaped structure of a bond-preventing agent with a liquid composition, e.g. a polymeric bonding composition such as one that contains uncured silicone rubber, to attain an overcoat layer of a desired shape. The shaped structure of a bond-preventing agent can be formed by coating over an outer surface of a support structure, for example, a mandrel or a tube, to form a residual coating of a particular shape.
One embodiment of the present invention relates to dipping a mandrel in a liquid composition, such as polymeric composition to form an inner piece (or structure) over a surface of a mandrel, applying and shaping a residual coating of a bond-preventing agent over the outer surface of the inner piece, and coating at least a portion of the structure resulting from the previous steps with a liquid composition to form a shaped structure having an overcoat on an inner piece.
Another embodiment of the present invention relates to a method of making a polymeric structure in accordance with one of the above methods wherein a fluid-filled cavity is formed between an inner polymeric layer and an outer polymeric layer.
Yet another embodiment of the present invention relates to a method of making a polymeric structure in accordance with one of the above methods wherein an outer polymeric layer only partially encapsulates an inner polymeric layer such that only one end of the outer polymeric layer is attached to the polymeric structure. This method might be utilized to form a polymeric structure having an umbrella-like structure.
It will be appreciated that shaped structures of varying shapes can be formed by the present invention. The shaped structures formed by the present invention might be hollow, liquid-filled, gel-filled, etc. and/or might include a solid piece as well as combinations thereof.
The coating of the bond-preventing agent can have a varying thickness on different portions of an outer surface of the inner piece. The coating of the bond-preventing agent remaining on the inner piece before the coating of the liquid composition is herein referred to as the “residual coating.” The shape of the overcoat layer results from the varying thicknesses of the residual coating of the bond-preventing agent.
In one embodiment, the forming of residual coating of varying shapes can be done by coating portions of an outer surface of the inner piece with a bond-preventing agent in a plurality of dipping steps by immersing the inner piece into the bond-preventing agent to a desired depth for a desired length of time and subsequently removing the inner piece from the bond-preventing agent. The desired depth and the desired length of time for each of the plurality of dipping steps is selected so that a residual coating of bond-preventing agent of desired thickness and shape remains on portions of the inner piece following the plurality of dipping steps. The residual coating has a specific shape as a result of the variation between the depth of any two of the plurality of dipping steps, the number of dipping steps, the length of time between any two of the plurality of dipping steps, and the varying speeds of withdrawal from the liquids in dip tanks. By appropriate coating and stripping sequence, the bond-preventing agent can be sculpted to result in desired, symmetrical shapes much as the shapes achievable using a lathe. The sculpted residual coating can have varying thickness, curves, and angles, and therefore a specific, desired shape. By subsequently coating the residual coating of bond-preventing agent, which co
Conway Anthony J.
Conway Philip J.
Fryar, Jr. Richard D.
McDowell Suzanne E.
Merchant & Gould P.C.
Rochester Medical Corporation
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