Machining method for degradable polymer intravascular stent

A technology for degrading polymers and processing methods, which is applied in the processing field of degradable polymer vascular stents, can solve the problems of small radial support force of stents, high rebound rate, high polymer viscosity, etc. The effect of radial support force and smooth surface of the stent

Inactive Publication Date: 2015-12-16
天津索玛科技有限公司
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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 th

Method used

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  • Machining method for degradable polymer intravascular stent

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Experimental program
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Effect test

Embodiment 1

[0024] A degradable polymer vascular stent, using PLLA as a raw material, the molecular weight of PLLA is 800,000, the specific processing steps are as follows: (1) Tube forming: select L-polylactic acid PLLA with an average molar molecular weight of 800,000 as the stent matrix material, and The material is heated to 196°C in the plastic molding extruder (the melting point of PLLA is 180°C), the pressure is set to 9MPa, and other conditions are the same as the conventional extrusion process. After the material is completely melted to a uniform state, it is removed from the Extruded in a molding die to obtain a pipe with an outer diameter of 3.3 mm and a wall thickness of 0.21 mm.

[0025] (2) Laser engraving into a stent matrix: laser engraving is performed on the shaped pipe obtained in step (1) using laser light source equipment to obtain a stent matrix.

[0026] (3) Surface polishing of the stent matrix: suspend the stent matrix after laser engraving in step (2) in the ultr...

Embodiment 2

[0029] A kind of degradable polymer vascular stent, with embodiment 1, difference is: the molecular weight of PLLA is 200,000 in the step (1), and this polymer material is heated to 192 ℃ (the fusing point of PLLA) in plastic molding extruder The temperature is 180°C), the pressure is set to 14MPa, and other conditions are the same as the conventional extrusion process. After the material is completely melted to a uniform state, it is extruded from the molding die to obtain an outer diameter of 3.3mm and a wall thickness of 0.21mm tubing.

[0030] In step (3), the surface of the stent base is ultrasonically cleaned and polished for 20 minutes, and the cleaning agent solution is ethanol.

[0031] Finally, a clean polymer vascular stent was obtained, and its mechanical properties were tested, and it was concluded that under the pressure of 82kPa, the diameter change rate of the stent obtained by adopting the technical solution of Example 1 was 13.7%. The change rate of the diam...

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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 ...

Claims

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Application Information

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IPC IPC(8): B23P15/00A61L31/06A61L31/14A61L31/16
CPCB23P15/00A61L31/06A61L31/148A61L31/16A61L2400/18A61L2420/02
Inventor 安桂生董世敏李策杨运燕
Owner 天津索玛科技有限公司
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