The present invention relates to multiple layered laminated medical-surgical tubing employing different layers of different plastic materials.
Medical-surgical tubings are widely employed in the medical field for analysis and treatment of patients. Generally, such tubing is made of an extruded plastic material. For example, polyethylene is widely employed in surgical tubing. U.S. Pat. No. 3,618,614, for example, discloses a multiple wall surgical tubing for stomach, thoracic or rectal use wherein like plastics such as polyethylene are bonded together. One of the layers is provided with a radiopaque material and the other is a clear tube. The composite tube may therefore be readily observed by fluoroscopic apparatus. The clear layer provides the desired physical characteristic such as smoothness or hardness. Vinyl plastic layers may also be similarly formed to provide radiopaque medical-surgical tubing.
In various applications, particularly for transporting of blood, interveneous fluids and the like, the migrating characteristic of the plastic employed must be carefully considered to prevent unacceptable contamination of the fluid. Thus, in dialysis equipment for treatment of kidney disease and the like, it is extremely important that there be essentially no contamination of the blood. In such medical application, polyvinyl chloride (PVC) is widely employed as the material for the medical-surgical tubing. Such material is basically, however, a clear brittle thermoplastic. In order to convert such brittle material into a flexible material, suitable plasticizors are added and may form as much as 50% of the finished product. In addition, lubricants and stabilizers may also be required. Although such materials are presently employed for medical applications, the possible migrating characteristic of additive materials demands careful attention in the manufacture and use. A polyurethane tubing has been suggested for such use because it is a stable material which is a relatively soft, flexible material without essentially any additives, and therefore minimizes possibility of migration of contaminants into or from the fluid. Polyurethane also has good flow characteristics and thus has many significant advantages. The cost, however, is significantly greater than polyvinyl chloride and such use has generally been limited to exceptional biological blood compatability applications. The terminology medical-surgical tubing is employed to define that unique class of tubing employed in the in vivo treatment of human patients and wherein the tubing is introduced into the patient's body or otherwise connected thereto for transfer of fluids and is otherwise used in the analysis and study of fluids related to treatment of human patients.
Although various medical-surgical tubing is therefore readily available for the various analysis, there is a very significant need for a low cost nonmigratory medical-surgical tubing where exceptional high degrees of purity are demanded.