JPH09192229A - Manufacture of catheter tube containing contrast medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decolarize discoloration produces on a tube in molding by heat treatment and produce the tube without any discoloration by heating and melting fluororesin containing contrast medium so as to be molded into the tube and heat treating the tube at a temperature lower that melting point of the resin. SOLUTION: A substance formed into a tube by heating and melting fluroresin contrast medium is heat treated at a temperature lower than the melting point of the resin in manufacturing a catheter tube containing contrast medium. Discoloration of the tube produced by hear treatment performed twice is depolarized by layer heat treatment so as to provide the tube without any discoloration. As a concrete case, barium sulfate, etc., are added to ethylene- ethylene tetrafluoride copolymer resin (ETFE) powder, heater and melt at approximately 300 deg.C so as to be molded into pellets. After the pellets are heated and melt at approximately 300 deg.C so as to be bolded into the tube by extrusion, the molded tube is hear treated at approximately 200 deg.C for roughly 8 hours so that the catheter tube without any discoloration is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved method for manufacturing a catheter tube containing a contrast medium.

[0002]

2. Description of the Related Art Conventionally, fluororesins having good biocompatibility have been used.
BACKGROUND ART A catheter tube mixed with an X-ray contrast agent such as barium sulfate or bismuth oxide is used as an indwelling needle that is punctured and fixed to a blood vessel when performing infusion or blood transfusion, for example.
Even if a part of the indwelling needle as described above is accidentally cut during use and enters the vascular system in the body, it is easy to use an X-ray radiograph because of the X-ray contrast agent contained in the vessel wall. The location can be confirmed at. The catheter tube is also used as a catheter that is inserted into the human body and has its tip reach a target site while being seen through X-rays for the purpose of collecting blood from the heart and injecting drugs into the internal organs. .

[0003]

By the way, the above-mentioned barium sulfate or bismuth oxide is generally used as the contrast agent for the catheter tube. When this contrast agent is mixed in the resin, it is processed at a high temperature of 300 ° C. to 400 ° C. with a fluorine-based resin having a high molding temperature.
During processing, a part of the fluorine resin is thermally decomposed to generate a decomposition product such as fluorine gas or hydrogen fluoride. As a result, there is a problem that the decomposition product generated from the fluorine resin and the contrast agent dispersed in the resin chemically react with each other, causing discoloration of the molded product, which tends to result in poor appearance. In addition, this may avoid the physiological feelings of the doctor or patient who uses the tube.

In general, as a method of manufacturing the catheter tube, first, a contrast agent is kneaded into a heat-melted fluororesin and molded into pellets. Then, a method is adopted in which the pellets are heated and melted again and molded into a tube by an extruder. Therefore, until it becomes a tube, it will be subjected to a thermal history twice higher than the melting point of the fluororesin, and the discoloration due to a chemical reaction tends to become large. For example, in the case of a fluororesin raw material containing barium sulfate, barium sulfate is white and the fluororesin raw material is white or translucent milky white, but the tube formed by heating and melting is discolored to grayish white. Further, in the case of the fluororesin raw material containing bismuth oxide, the bismuth oxide is yellow, and the fluororesin raw material is white or translucent milky white, but the tube formed by heating and melting is discolored to gray.

As a method for solving the above problem, X covered with a silica gel film or an anhydrous metal oxide film so as to prevent contact between a decomposition product generated from a fluororesin and an X-ray contrast agent.
Method of mixing linear contrast agent particles with resin (Japanese Patent Laid-Open No. 2-252)
No. 466, JP-A-3-26276) have been proposed.

However, in the above-mentioned manufacturing method, a film material for covering the X-ray contrast medium must be specially prepared, and further, a step of coating the X-ray contrast medium particles with the film material is required. However, there is a disadvantage in that the product becomes complicated and the cost of the product becomes high.

The present invention has been made in view of the above problems, and in a very simple process, discoloration of a tube caused by a reaction between a contrast agent and a fluororesin due to two heat treatments up to the tube forming process is caused. The main object of the present invention is to provide a method for producing a catheter tube containing a contrast agent that can be decolorized.

[0008]

In order to achieve the above object, a method of manufacturing a catheter tube containing a contrast medium according to the present invention comprises a step of heating and melting a fluorocarbon resin containing a contrast medium to form a tube, After processing the tube,
The gist is that it comprises a step of heat treatment at a temperature 40 to 80 ° C. lower than the melting point of the resin.

According to the above-mentioned manufacturing method, after the tube forming process, the heat treatment at the melting temperature of the fluororesin or lower is applied, which is caused by the reaction between the contrast agent and the fluororesin by the heat treatment twice until the tube forming process. The generated discoloration of the tube is decolorized by the subsequent heat treatment, so that a tube without discoloration is finally obtained.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Ethylene-tetrafluoroethylene copolymer resin (ETFE) powder is mixed with barium sulfate or bismuth oxide powder, heated and melted at 300 ° C., sufficiently kneaded and molded into pellets. The pellets were heated and melted at 300 ° C. and extruded into a tube shape by a screw extruder, and then the formed tube was heat-treated at a temperature (200 ° C.) lower than the melting point of the resin for 8 hours. The tube after this heat treatment and the tube not subjected to heat treatment were evaluated by comparing the appearances (color tones), and the one to which barium sulfate was added as a contrast agent was grey-white after tube molding, The heat-treated product turned white. On the other hand, the tube to which bismuth oxide powder was added as a contrast agent was gray after molding and yellow after heat treatment.

[0011]

【Example】

Example 1 85% by weight of ethylene-tetrafluoroethylene copolymer resin (ETFE) (melting point 260-270 ° C.) and 15% by weight of barium sulfate as a contrast agent were mixed, heated and melted at 300 ° C., and sufficiently kneaded. The mixture was molded into pellets, and the pellets were heated and melted at 300 ° C. and extruded into a tube with a screw extruder to be molded. Then, it heat-processed at 200 degreeC for 8 hours, decolored, and the catheter tube without discoloration was obtained.

Example 2 A catheter tube without discoloration was obtained in the same manner as in Example 1 except that bismuth oxide was used instead of barium sulfate in Example 1 as the contrast agent.

Example 3 85% by weight of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA) (melting point 302 to 310 ° C.) and 15% by weight of bismuth oxide as a contrast agent are mixed and heated at 350 ° C. to melt. Then, the mixture was sufficiently kneaded and molded into pellets, and the pellets were heated and melted at 350 ° C. and extruded into a tube by a screw extruder. Then, it heat-processed at 240 degreeC for 8 hours, decolorized, and the catheter tube without discoloration was obtained.

Example 4 Vinylidene fluoride resin (PVDF) (melting point 156-170)
C.) 85% by weight and barium sulfate 15% by weight as a contrast agent are mixed, heated and melted at 210 ° C., sufficiently kneaded to form pellets, and the pellets are heated and melted at 210 ° C. and screw extruded. It was extruded into a tube shape by a machine. Then, it heat-processed at 110 degreeC for 8 hours, decolorized, and the catheter tube without discoloration was obtained.

Comparative Examples 1 to 4 The catheter tubes having no final heat treatment step of Examples 1 to 4 were designated as Comparative Examples 1 to 4.

The formulations and appearances of Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 1 below.

[0017]

[Table 1]

As shown by the results of the above Examples and Comparative Examples, in the process of manufacturing a catheter tube from a fluorocarbon resin containing a contrast agent, the tube after molding is heat-treated to obtain a tube without discoloration. It was confirmed. The amount of the contrast agent blended varies depending on the purpose of use of the tube containing the contrast agent and the type of the contrast agent, but is usually selected within the range of 5 to 20% by weight based on the resin. Further, even when the contrast agent is treated with a surface treatment agent in order to improve the dispersibility when the fluororesin and the contrast agent are kneaded, the same effect as described above can be obtained. Further, it is desirable that the heat treatment of the tube after molding is performed at a temperature lower than the melting point of the resin by 40 to 80 ° C. for 6 to 12 hours. More preferably,
It is preferable to perform heat treatment at a temperature 50 to 70 ° C. lower than the melting point of the resin for 6 to 12 hours. When the heat treatment is performed at a high temperature close to the melting point, the catheter tube may be largely shrunk or deformed. Further, the decolorizing effect is poor at low temperatures.

The catheter tubes of Example 1 and Comparative Example 1 were analyzed by the DSC (differential scanning calorimeter) method under the following test conditions. Testing organization: Japan Chemicals Inspection Association Measuring instrument: TA-3000, DSC-30 manufactured by METTLER CORPORATION Temperature rising rate: 10 ° C./min Atmosphere: 40 ml / min N ₂ sample amount: 5 mg

FIG. 1 shows D of the catheter tube of Example 1.
It is an SC chart, and the endothermic curve due to the crystalline becoming amorphous is seen before the melting endothermic peak. On the other hand, FIG. 2 is a DSC chart of the catheter tube of Comparative Example 1, but the above endothermic curve other than the melting endothermic peak is not seen. Table 2 below shows the melting points and melting energies of both, and the melting energy of Example 1 is higher. From these facts, it is considered that one of the causes of decolorization is that crystallization is increased by heat treatment at a temperature lower than the melting point after the tube forming process.

[0021]

[Table 2]

[0022]

As described above, according to the method of manufacturing a catheter tube containing a contrast agent according to the present invention, a step of heating and melting a mixture of a contrast agent and a fluororesin to form a pellet, and the step of forming the pellet again Discoloration due to the reaction between the fluororesin and the contrast agent due to the heat history of two times when melted by heating and extruded into a tube shape is decolorized by heat treatment after the tube molding process, and finally it has a good appearance with no discoloration. The catheter tube can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a DSC chart of a catheter tube obtained according to an example of the present invention.

FIG. 2 is a DSC chart of a catheter tube obtained in a comparative example.

Claims (1)

[Claims] 1. A step of heating and melting a fluorocarbon resin containing a contrast agent to form a tube, and a step of heat-treating the tube after the molding at a temperature 40 to 80 ° C. lower than the melting point of the resin. A method of manufacturing a catheter tube containing a contrast agent, comprising: