CN112060559A

Movatterモバイル変換

Info

Publication number: CN112060559A
Application number: CN202010904808.8A
Authority: CN
Inventors: 戴燕; 陈果; 何成
Original assignee: Sichuan Xingtai Pule Medical Technology Co ltd
Current assignee: Lepu Shenzhen International Development Center Co ltd
Priority date: 2020-09-01
Filing date: 2020-09-01
Publication date: 2020-12-11

Abstract

The invention discloses a processing method of a polymer pipe for a vascular stent, which comprises the following steps: (a) heating the formed polymer pipe to a first temperature, and preserving heat for 10-20min at the first temperature; (b) quickly putting the heated polymer pipe into a cavity of a mold, introducing hot air into the polymer pipe at a constant speed, expanding and deforming the pipe in the radial direction under the action of the hot air, and attaching the outer wall of the expanded pipe to the inner wall of the mold; (c) opening circulating cooling water, introducing cold air into the pipe, rapidly cooling the pipe to room temperature, and opening the die to obtain a deformed pipe; the mold is provided with a cooling water tank, and circulating cooling water is introduced into the cooling water tank. The pipe expands in the die and is cooled rapidly under the action of the die, so that the orientation of the polymer is maintained, the breaking strength of the polymer is improved, and the support performance of the polymer pipe is enhanced.

Description

Processing method of polymer pipe for intravascular stent

Technical Field

The invention belongs to the technical field of medical instruments, and particularly relates to a processing method of a polymer pipe for a vascular stent.

Background

The blood vessel stent for coronary artery interventional therapy is composed of a permanent metal bare stent, a drug-eluting permanent metal stent, a degradable polymer stent and the like. The degradable polymer stent is made of biodegradable materials, can support blood vessels after being implanted into diseased sites, rebuilds the blood circulation function of the blood vessels, and is degraded into non-toxic products in a human body after treatment is completed, and is discharged out of the body along with normal metabolism of an organism and disappears. The degradable stent has more advantages, but the polymer can solve the defects of poor mechanical property, small radial supporting force, low breaking strength and the like of most polymer stents, and limits the application of the degradable stent.

Disclosure of Invention

The invention aims to: the method solves the defects in the prior art and provides a method for processing a polymer pipe for a vascular stent.

In order to achieve the purpose, the invention adopts the technical scheme that: a method of processing a polymeric tube for a vascular stent, the method comprising:

(a) heating the formed polymer pipe to a first temperature, and preserving heat for 10-20min at the first temperature;

(b) quickly putting the heated polymer pipe into a cavity of a mold, introducing hot air into the polymer pipe at a constant speed, expanding and deforming the pipe in the radial direction under the action of the hot air, and attaching the outer wall of the expanded pipe to the inner wall of the mold;

(c) opening circulating cooling water, introducing cold air into the pipe, rapidly cooling the pipe to room temperature, and opening the die to obtain a deformed pipe;

the mold is provided with a cooling water tank, and circulating cooling water is introduced into the cooling water tank.

Further, the cooling water tank is spirally arranged along the circumferential direction of the cavity of the mold.

Further, the first heating temperature is between the glass transition temperature and the melting temperature of the polymerization.

Further, the material of the polymer pipe is polylactic acid.

Further, the temperature for heating the polymer pipe is 55-65 ℃.

Further, the wall thickness of the deformed pipe is 100-200 um.

Further, the temperature of the hot air is 50-70 ℃.

Further, the temperature of the cold air is 20-25 ℃.

Due to the adoption of the technical scheme, the invention has the beneficial effects that:

in the processing method, the heated polymer pipe is placed in a mould, hot air is introduced into the pipe, so that the pipe expands and deforms under the action of the hot air, the polymer pipe undergoes radial and axial stretching orientation during deformation, the deformed pipe is attached to the mould, the mould with circulating cooling water rapidly cools the pipe to room temperature, and the orientation of the polymer in the deformation process is maintained. The radial supporting force of the polymer tube processed by the method is increased, the breaking strength is improved, and the mechanical property of the intravascular stent processed by the polymer tube is excellent.

Drawings

Figure 1 is a schematic cross-sectional view of a tube according to the invention before deformation;

FIG. 2 is a schematic cross-sectional view of a deformed tube of the present invention;

reference numerals: 1-mould, 2-cooling water tank and 3-pipe.

Detailed Description

Embodiments of the present invention will be described in detail with reference to the accompanying fig. 1-2.

Example 1:

(a) heating the extrusion-molded polylacticacid polymer pipe 3 to 55 ℃, softening thepolymer pipe 3, and keeping the temperature at 55 ℃ for 20min, wherein the wall thickness of thepolymer pipe 3 is 500 um;

(b) quickly placing the heatedpolymer pipe 3 into a cavity of a mould 1, continuously introducing hot air of 55 ℃ into thepolymer pipe 3 at a constant speed, radially expanding and deforming thepipe 3 in the cavity under the action of the hot air, and attaching the outer wall of the expandedpipe 3 to the inner wall of the mould 1;

(c) opening the recirculated cooling water in the mould 1 to letting in 20 ℃ cold air in totubular product 3, the inside cold air of the lower mould 1 of temperature andtubular product 3 acts ontubular product 3 simultaneously, the rapid heat withtubular product 3 is taken away, makestubular product 3 cool off to the room temperature fast, and the die sinking obtainstubular product 3 after the deformation, and the wall thickness oftubular product 3 that obtains is 100 um.

In this embodiment, the used mold 1 is a tubular mold, the cavity of the mold 1 is a circular tube, the mold 1 is provided with acooling water tank 2, circulating cooling water is introduced into thecooling water tank 2, thecooling water tank 2 is spirally distributed by taking the axis of the cavity as the center, and the surface of the cavity is smooth.

Thepolymer tube 3 obtained in the embodiment is subjected to laser engraving to prepare a polymer stent, which is marked as a No. 1 stent, and the radial supporting force and the fracture strength of the stent of the No. 1 stent are measured in vitro.

Example 2:

(a) heating the extrusion-molded polylacticacid polymer pipe 3 to 60 ℃, softening thepolymer pipe 3, and keeping the temperature at 60 ℃ for 10min, wherein the wall thickness of thepolymer pipe 3 is 600 um;

(b) rapidly placing the heatedpolymer pipe 3 into a cavity of a mould 1, introducing 60 ℃ hot air into thepolymer pipe 3 at a constant speed and continuously, wherein thepipe 3 in the cavity expands and deforms along the radial direction under the action of the hot air, and the outer wall of the expandedpipe 3 is attached to the inner wall of the mould 1;

(c) opening the recirculated cooling water in the mould 1 to letting in 20 ℃ cold air in totubular product 3, the inside cold air of the lower mould 1 of temperature andtubular product 3 acts ontubular product 3 simultaneously, the rapid heat withtubular product 3 is taken away, makestubular product 3 cool off to the room temperature fast, and the die sinking obtainstubular product 3 after the deformation, and the wall thickness oftubular product 3 that obtains is 200 um.

Thepolymer tube 3 obtained in the embodiment is subjected to laser engraving to prepare a polymer stent, the polymer stent is marked as a No. 2 stent, and the radial supporting force and the fracture strength of the stent of the No. 2 stent are measured in vitro.

Example 3:

(a) heating the extrusion-molded polylacticacid polymer pipe 3 to 65 ℃, softening thepolymer pipe 3, and keeping the temperature at 65 ℃ for 10min, wherein the wall thickness of thepolymer pipe 3 is 500 um;

(b) quickly placing the heatedpolymer pipe 3 into a cavity of a mould 1, introducing 70 ℃ hot air into thepolymer pipe 3 at a constant speed and continuously, wherein thepipe 3 in the cavity expands and deforms along the radial direction under the action of the hot air, and the outer wall of the expandedpipe 3 is attached to the inner wall of the mould 1;

(c) opening the recirculated cooling water in the mould 1 to letting in 25 ℃ cold air in totubular product 3, the inside cold air of the lower mould 1 of temperature andtubular product 3 acts ontubular product 3 simultaneously, the rapid heat withtubular product 3 is taken away, makestubular product 3 cool off to the room temperature fast, and the die sinking obtainstubular product 3 after the deformation, and the wall thickness oftubular product 3 that obtains is 100 um.

Thepolymer tube 3 obtained in the embodiment is subjected to laser engraving to prepare a polymer stent, which is marked as a No. 3 stent, and the radial supporting force and the fracture strength of the stent of the No. 3 stent are measured in vitro.

Example 4:

(a) heating the extrusion-molded polylacticacid polymer pipe 3 to 55 ℃, softening thepolymer pipe 3, and keeping the temperature at 55 ℃ for 20min, wherein the wall thickness of thepolymer pipe 3 is 600 um;

(c) opening the recirculated cooling water in the mould 1 to letting in 25 ℃'s cold air in totubular product 3, the inside cold air of the lower mould 1 of temperature andtubular product 3 acts ontubular product 3 simultaneously, the rapid heat withtubular product 3 is taken away, makestubular product 3 cool off to the room temperature fast, and the die sinking obtains thetubular product 3 after the deformation, and the wall thickness oftubular product 3 that obtains is 200 um.

Thepolymer tube 3 obtained in the embodiment is subjected to laser engraving to prepare a polymer stent, which is marked as a No. 4 stent, and the radial supporting force and the fracture strength of the stent of the No. 4 stent are measured in vitro.

In the comparative test example, polylactic acid was added to a twin-screw extruder to extrude apipe 3 having a wall thickness of 100um, and the stent No. 5 was fabricated by the same laser engraving process as in example 1; thepipe 3 with the wall thickness of 200um is obtained through a double-screw extruder, and the No. 6 bracket is obtained through laser engraving.

The radial support and fracture strength of the stents of examples 1-4 and comparative examples are shown in the following table:

bracket numbering	Number 1	Number 2	No. 3	Number 4	Number 5	Number 6
							Radial support force (Kpa)	156	148	145	158	101	105
Breaking Strength (Kpa)	262	248	250	265	189	192

It should be noted that the results obtained in the above tables were all measured under the same experimental conditions, and the outer diameters of the respective stents were the same.

As can be seen from the above table, the radial support force and the breaking strength of the stents prepared in this example are improved in the stents nos. 1-4 compared with the stents nos. 5 and 6. Thepolymer pipe 3 expands in the die and is rapidly cooled under the action of the die, so that the orientation of the polymer is maintained, the breaking strength of the polymer is improved, and the supporting performance of thepolymer pipe 3 is enhanced.

Claims

1. A method of processing a polymeric tube for a vascular stent, the method comprising:

2. The method of processing a polymer tube for a vascular stent as set forth in claim 1, wherein: the cooling water tank is spirally arranged along the circumferential direction of the cavity of the mold.

3. The method of processing a polymer tube for a vascular stent as set forth in claim 1, wherein: the first heating temperature is between the glass transition temperature and the melting temperature of the polymerization.

4. The method of processing a polymer tube for a vascular stent as set forth in claim 1, wherein: the polymer pipe is made of polylactic acid.

5. The method of processing a polymer tube for a vascular stent as set forth in claim 4, wherein: the temperature of the polymer pipe is 55-65 ℃.

6. The method of processing a polymer tube for a vascular stent as set forth in claim 1, wherein: the wall thickness of the deformed pipe is 100-200 mu m.

7. The method of processing a polymer tube for a vascular stent as set forth in claim 1, wherein: the temperature of the hot air is 50-70 ℃.

8. The method of processing a polymer tube for a vascular stent as set forth in claim 1, wherein: the temperature of the cold air is 20-25 ℃.