Machining method for degradable polymer intravascular stent

Abstract

The invention provides a machining method for a degradable polymer intravascular stent. The machining method comprises the following steps that firstly, a pipe is formed; secondly, a stent base body is formed through laser engraving; thirdly, the surface of the stent base body is polished. In the first step, the pipe is formed through the extrusion technology that cold pressurization is carried out on a plastic pipe, wherein polymer raw materials for the stent base body are heated in a plastic extruder to the temperature higher than the corresponding melting point temperature Tm and lower than the extruding temperature in the normal pressure extruding technology by 5-15 DEG C, 5-20 MPa pressure is applied at the same time, the raw materials are extruded out of a mold of the extruder with the temperature and the pressure maintained, and slow cooling is carried out. Compared with the prior art, by means of the machining method for the degradable polymer intravascular stent, the strength of the obtained intravascular stent is higher, the overall radial supporting force is higher, and the surface of the stent is smoother and free of flaws.

Description

technical field [0001] The invention relates to the field of material processing and implantable medical devices, in particular to a processing method of a degradable polymer vascular stent. Background technique [0002] At present, degradable biomaterials such as polylactic acid (PLA) and poly-L-lactic acid (PLLA) are used to prepare peripheral vascular stents to improve the deficiencies of metal stents, such as metal stents, which can easily lead to vascular restenosis and secondary surgery. [0003] Common biodegradable polymer materials (such as polylactic acid, polyglycolic acid, polycaprolactone, etc.) have relatively weak mechanical properties, and their Young's modulus is only about 0.1-4GPa, and their strength is only 40-80MPa. Due to the low mechanical strength of the material, after the stent is made of these materials, the radial support force of the stent is relatively small, generally below 100KPa, so it is difficult to support the blood vessel. Moreover, the ...

AI Technical Summary

Problems solved by technology

Due to the low mechanical strength of the material, after the stent is made of these materials, the radial support force of the stent is small, generally below 100KPa, so it is difficult to play the role of supporting blood vessels

Moreover, the elastic range of these materials is larger than that of traditional metal stent materials, so that the prepared stent has a high rebound rate after expansion, which is also a big problem

In addition, these materials have a small plastic deformation zone and poor toughness, making the stent prone to adverse events such as fracture during expansion.

[0004] Existing methods for preparing degradable polymer stents mainly include: direct stent injection molding, weaving polymer filaments, thermosetting molding, etc. These preparation methods all require molds with high precision, and because the mold space is small, The high viscosity of the polymer is not conducive to the flow of the polymer, so it is easy to cause defects such as uneven scaffold structure and insufficient mechanical support performance.

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