New form of medical catheter technology

Medical catheters are one of the most common tools in the hands of doctors, such as balloons, sheath tubes, and delivery systems. These catheters contain a basic underlying technology, that is, the processing of polymer materials, and the application of extrusion processing technology occupies the majority. The polymer material is processed by extrusion process into a simple raw material pipe, and then after various subsequent assembly, the final state of the catheter instrument is formed. The hardness, tolerance, toughness and so on represented by the raw material pipe correspond to the various performance points of clinical requirements. It should be said that a good extrusion process can meet almost all the parameters and performance requirements of medical catheters. However, with the clinical demand for some instruments with low tolerances, ultra-thin wall thickness and high torque, the extrusion process is somewhat difficult. Therefore, the dip coating technology has come into play. Simply understood, dip coating process is the liquid polymer material, and then by dipping the tool (mandrel) into the solution, the process of forming the raw material pipe (as shown in the figure above). Figuratively understood, it is like layers of paint, forming thickness and then becoming tubular. For clinical purposes, there are several most practical and important characteristics: 1. Tolerance: for extrusion and subsequent processing, the tolerance of ±0.01mm is extremely difficult, which is an unavoidable processing reality. However, for the dip coating process, very small tolerances can be easily achieved. Different from the extrusion molding, the tube under the dip coating process generally has to go through 30-50 times of dip coating to form a thickness of 1-2mm, the wall thickness formed by dip coating once can be said to be extremely thin, and the corresponding tolerance is also very small. 2. Torque: Doctors want the catheter in their hands to be flexible and natural in the blood vessels, which is called good torsion control in the jargon. The pipe produced by the traditional process can be close to 1:1 torque, but for the dip process, it is inherently 1:1 property. During the coating process, each layer of the catheter is almost "fused" with other parts through the attachment of liquid materials, rather than a simple superposition of materials. It's this fusion that makes the catheter one. The 90 degree rotation in the doctor's hand is also reflected in the 90 degree rotation in the distal blood vessel. 3. Performance composite: The performance superposition of polymer materials, whether it is raw material modification or subsequent composite, must consider the family and molecular chain of the material itself, there is a certain degree of difficulty. For the coating process, as long as the different polymers are liquid, and then in the way of "you a layer, I a layer", the performance of the two will be combined, you can achieve a more satisfactory comprehensive performance change. At the same time, the performance ratio of the two can be adjusted by the number of dipping.