1. Field of the Invention
The invention relates to a uridom for use as an external catheter in a male urinary incontinence device, manufactured by thermoplastic processing of a non-preprocessed thermoplastic elastomeric base material.
2. Description of the Related Art
For aiding male urinary incontinence and for use in hospitals in connection with treatment and surgery of urethral disorders a urinary incontinence device is normally used, consisting of a uridom designed to be arranged as an external catheter on the penis and having a comparably short tube which via a hose is connected to a urine collection bag that is normally fastened to the user's leg.
Uridoms for use in such incontinence devices are produced in a conventional way like other elastic tubular sheaths to be fastened on parts of the human body, i.e. of natural latex by a multi-step dipping process, during which a mandrel of the same size and shape as the part of the body concerned is dipped repeatedly into a latex solution, which in between immersions is cured on the mandrel.
This known method which, i.a. is disclosed in the European Publication No.0 390720 suffers from several deficiencies in practice.
The latex used is thus a natural product, which may vary in respect of quality and composition and may i.a. contain allergy-inducing proteins, which in an industrial production is an impediment to ensuring a constant product uniformity with an optimum skin comfort. This is further intensified by the fact that the latex solution contains a vulcanization system, which among other substances contains nitrosamines and sulphur.
Furthermore, the lifetime of latex products is shortened by the fact that their structure contains double linkings which are sensitive when exposed to UV radiation, resulting in a decomposition of the material, whereby the properties of the product may deteriorate drastically.
In addition, this production method leaves much to be desired from an environmental and manufacturing point of view. In the process ammonia is employed and often also methanol and inorganic salts, wherefore a continuous destruction of chemical residues that are detrimental to the environment must take place. A possible waste resulting from a faulty production or excess material cannot be recycled but must be discarded and destroyed.
Also, the latex dipping method is a relatively lengthy process with a typical production lead time in the range of 24 hours, meaning that industrial mass production requires comprehensive machinery.
To alleviate or avoid these disadvantages a number of propositions have been made relating to the production of uridoms and similar products using different materials and methods.
The Danish patent application No.1549/79 thus discloses a method for manufacturing prophylactic devices such as condoms and fingerstalls by thermomoulding, whereby an extruded piece of a film of a thermoplastic polyurethane elastomer is deformed by means of a mandrel. The method thus requires a preprocessing of the PUR material into film and a subsequent extrusion into small units which in the moulding process are heated to a temperature high enough to soften the material.
Applying this method it is difficult to obtain the thin wall thickness, 150-200 u, which is required of a uridom and, added to this, polyurethane does not have sufficiently good elastic properties to be a user-friendly alternative to the conventional latex uridoms, inasmuch as a polyurethane product will be perceived as tight.
In addition, base materials which are based on polyurethanes contain substances that are detrimental to the environment, such as, e.g. isocyanate.
U.S. Pat. No. 4,817,593 discloses a method for manufacturing condoms by which a mandrel is dipped into a polyurethane solution in an organic solution and is cured at a high temperature. Contrary to the latex technology the mandrel is dipped into the solution only once, but the method does not remedy the above-mentioned deficiencies in using polyurethane as base material.
U.S. Pat. No. 4,808,174 discloses a method for manufacturing condoms of plastics such as polyethylene, polypropylene or vinyl. The method is identical to the one described in the above-mentioned Danish patent application, i.e. preprecessed films are heated to a temperature which is high enough to soften them and are then moulded on a mandrel.
The Danish publication No.137 243 describes a method for manufacturing rubber products by repeated dipping into an elastomer solution consisting of a SBS or SIS block copolymer strained with 5-100 percentage by weight of a mainly naphtenic/aromatic petroleum oil and dissolved in 200/1200 percentage by weight of an aliphatic hydrocarbon, preferably petrol. The method first and foremost implies an environmental hazard, because comparably large quantities of solvents are employed and, furthermore, the thermoplastic block copolymers of the type described do not sufficiently remedy the problems of deterioration and wear which are found in latex products. It has also been found that in uridoms manufactured by applying this method, a comparatively high decontraction occurs which may be due to a too low softening temperature, and which entails that a rolled-up uridom is difficult to unroll after only a few weeks of storage.
In the Danish publication No.150 792 a method for manufacturing uridoms is proposed, according to which an extruded hose-like body of thermoplastic and elastic material is blown up in a mould. As possible materials to be used for the extrusion of the tubular body are mentioned granulated latex, rubber or thermoplastic raw material. The method has never been put into practice and the description does not give any guidelines for solving the specific product-related and environmental problems mentioned above- The publication must be considered as a rather theoretical proposition for a production method as an alternative to the known latex dipping process without providing adequate documentation for its industrial applicability.
The published international patent application WO 89/11258 discloses a contraceptive condom made of thermoplastic material and manufactured by blow extrusion or blow moulding, where a tubular film body is either extruded by an embedded air bubble or heated and put in a mould and blown up by means of compressed air. Subsequently, one end portion of the tubular body is automatically sealed closed.
For functional reasons it is desirable that the part of the tube which serves as drainage tube should have a certain rigidity with a view to its being connected to a tube connector and, in order to achieve an anti-kinking function, it is preferred that in an adjacent end portion of the otherwise thin-walled body portion a constriction should be provided to serve as an anti-kinking chamber.
The above-mentioned European patent application No.0390720 describes the manufacture of such a uridom by a conventional latex dripping process.