Large size balloon end stretch forming process

Abstract

The purpose of the present application is to provide a large-size balloon end stretch forming process capable of thinning the balloon end, which stretches the balloon on both sides step by step, first stretching the balloon shoulder and the balloon neck on one side, then stretching the balloon shoulder and the balloon neck on the other side, and the speed of the left side and the speed of the right side are different during the second stretching according to the material properties, so that the qualified rate of the produced balloon is higher whether it is the shoulder or the neck, and the performance is more stable. Through the process, the end thickness can be reduced by 70%, the neck thickness can be reduced by 60%, and the neck diameter can be reduced by 50%, to meet the needs of TPU large balloon welding and folding and holding in the later stage.

Description

Technical Field

[0001] This invention relates to the field of medical device manufacturing technology, specifically to a process for stretching and forming the end of a large-size balloon. Background Technology

[0002] Intra-aortic balloon counterpulsation (IABP) is a treatment method that involves inserting a balloon between the descending aorta and the renal artery via femoral artery puncture. Driven and controlled by an intra-aortic balloon counterpulsation pump, the balloon inflates during diastole and deflates at the end of diastole, thereby increasing coronary perfusion and reducing cardiac workload. The balloon is a crucial component of the IABP catheter, and its performance directly determines the overall performance of the IABP catheter.

[0003] The aortic counterpulsation balloon is a large-diameter balloon. After initial shaping and processing, the length, diameter, and thickness of the middle part of the balloon generally meet the requirements. However, the ends of the balloon, being relatively far from the central lumen from the heating and cooling modules, experience slower temperature rise and fall, and their temperatures are lower than those in the central lumen. Furthermore, the stretching of the balloon ends is not adequate. Specifically, the balloon ends include a tapered shoulder and a thin neck. The shoulder is particularly thick, affecting subsequent folding and gripping. Simultaneously, the large diameter and thickness of the thin neck at both ends lead to problems such as excessive assembly gaps, welding wrinkles, and excessively large weld diameters during subsequent assembly with the TIP tip and catheter. Ultimately, this results in an overall maximum balloon diameter that is too large, requiring a larger puncture site or reducing the balloon's permeability, among other adverse effects. Summary of the Invention

[0004] The purpose of this invention is to provide a large-size balloon end stretching and forming process that can thin the balloon end.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a large-size balloon end stretching and forming process, comprising the following steps:

[0006] S1) Place the initially stretched balloon into the re-stretching mold. The balloon straight tube section is placed inside the constant temperature water jacket, the balloon shoulder is placed inside the heat insulation jacket, and the balloon narrow neck section is placed inside the heating mold. The re-stretching mold includes the constant temperature water jacket, the heat insulation jacket, and the heating mold from left to right. The balloon after the initial stretching already has the balloon straight tube section and the balloon shoulder. However, the balloon shoulder material is relatively thick, and the diameter of the material tube part on the outside of the shoulder is relatively large. Therefore, it needs to be stretched again. When stretching again, only the parts that need to be stretched need to be stretched, that is, the balloon shoulder and the material tube section need to be heated. Other parts (i.e., the balloon straight tube section) do not need to be stretched.

[0007] S2) Connect both ends of the material tube to a CNC tensile testing machine. One end of the material tube is closed and the other end is connected to the air source. After the balloon is filled with gas, both ends of the balloon are closed and pressure is maintained. The material tube is stretched under the pressure.

[0008] S3) Keep the temperature of the constant temperature water jacket at T1, heat the heating mold to temperature T2, and then stretch the material tube at the processing end outward at a speed of V1. This step is mainly to thin the thickness of the balloon shoulder and form the balloon neck section. However, at this time, the balloon neck section has a small diameter and a thick thickness. After stretching, immediately retract the balloon neck section into the constant temperature water jacket and immediately cool and shape the stretched balloon shoulder.

[0009] S4) With the balloon in the inflatable state, the narrow neck of the balloon is completely placed in the heating chamber of the heating mold. The next step is to stretch and blow mold the narrow neck of the balloon.

[0010] S5) Heat the balloon neck section to temperature T2, and then stretch it at speeds V2 on the left and V3 on the right of a CNC tensile testing machine for a stretching time t1. At the same time as stretching, blow molding is performed on the balloon neck section. This step mainly stretches and blow molds the balloon neck section with a smaller diameter and thicker thickness in step S3), so that the balloon neck section with a smaller diameter and thicker thickness becomes a balloon neck section with a larger diameter and thinner thickness. After stretching, the balloon neck section is immediately returned to the constant temperature water jacket for cooling and shaping.

[0011] S6) Reverse the balloon direction and repeat steps S1), S2), S3), and S4).

[0012] S7) When the balloon is in the ventilated state, heat the balloon neck section to T2, and then stretch it at a speed of V4 on the left and V3 on the right of the CNC tensile testing machine for a stretching time of t1. At the same time as stretching, blow molding is performed on the balloon neck section (3). This step mainly involves stretching and blow molding the balloon neck section with a smaller diameter and thicker thickness at the other end, so that the balloon neck section with a smaller diameter and thicker thickness becomes a balloon neck section with a larger diameter and thinner thickness. After stretching, the balloon neck section is immediately returned to the constant temperature water jacket, and the stretched balloon neck section is cooled and shaped. The speed V4 is greater than V2.

[0013] S8), Remove the balloon.

[0014] The inner diameter of the constant temperature water jacket is 2mm larger than the standard diameter of the balloon, and its length is 30cm longer than the standard length of the balloon. This is because the balloon may shrink back during the shaping process.

[0015] In step S2), the CNC tensile testing machine applies a tensile force of 5N to 8N to both ends of the balloon, and the balloon is filled with air pressure of 15kPa to 30kPa.

[0016] In step S4), the boundary between the balloon shoulder and the balloon neck should be at the same position as the boundary of the heating cavity of the heating mold, so that only the balloon neck is precisely heated.

[0017] In steps S5) and S7), when the slender neck of the balloon retracts into the constant temperature water jacket, the CNC tensioning machines at both ends of the balloon move synchronously to ensure that the distance between the two ends of the material tube does not change.

[0018] Furthermore, the value of V1 ranges from 5 mm / s to 10 mm / s.

[0019] Furthermore, the value range of V2 is 3mm / s to 5mm / s, the value range of V3 is 2mm / s to 4mm / s, and the value range of V4 is 3.5mm / s to 5.5mm / s.

[0020] Furthermore, the temperature T1 of the constant temperature water jacket ranges from 10℃ to 18℃, and the temperature T2 of the heating mold ranges from 120℃ to 180℃.

[0021] The stretching time t1 ranges from 8s to 18s.

[0022] The axis of the CNC tensile testing machine coincides with the axis of the balloon and is arranged in a horizontal direction to ensure the uniformity of material redistribution during the stretching process.

[0023] In the above-described method, the balloon is stretched in stages on both sides. First, the shoulder and neck of one side of the balloon are stretched, and then the shoulder and neck of the other side are stretched. Due to the material properties, the speed of the second stretching differs between the left and right sides. This results in a higher yield rate for both the shoulder and neck of the produced balloon, and more stable performance. This process can reduce the end thickness by 70%, the thickness of the balloon neck by 60%, and the diameter of the balloon neck by 50%, meeting the requirements for subsequent welding and folding of the large TPU balloon. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the balloon structure;

[0025] Figure 2 This is a schematic diagram showing the fit between the balloon and the restretching mold. Detailed Implementation

[0026] To facilitate understanding, it is necessary to briefly describe the entire balloon molding process. First, a tube of uniform diameter is taken, with a small diameter and thick wall. Then, the tube is heated and pressurized under air pressure. A specific section of the tube expands to form the balloon's straight tube section 1, while the diameter of the tube outside this section remains almost unchanged. The portion between the balloon's straight tube section 1 and the tube forms a balloon shoulder 2 with a certain taper. The distal and proximal sections of the balloon shoulder 2 are stretched to be thinner, used for welding to the distal TIP head and proximal catheter, respectively. After pre-stretching, the balloon straight tube section 1 is stretched to its proper position. However, the balloon shoulder 2 at both ends of the straight tube section 1, as well as the distal and proximal sections of the balloon shoulder 2, are not fully stretched. Therefore, the balloon shoulder 2 needs to be stretched further, requiring the distal and proximal sections of the balloon shoulder 2 to be stretched into the thin neck section 3 of the balloon for welding to the TIP head and proximal catheter. Therefore, this invention is a process for re-stretching the pre-stretched balloon.

[0027] Firstly, the re-stretching mold consists of three parts: a constant-temperature water jacket A, a heat insulation jacket B, and a heating mold C. The heating mold C heats the tube portion that will form the balloon's narrow neck segment 3, rearranging the material in the balloon neck area and reshaping it to stretch and form the balloon's narrow neck segment 3. Since the balloon's straight tube segment 1 has already been stretched to the target degree during the pre-stretching stage, we do not want this segment to be stretched again during the re-stretching process. Therefore, the balloon straight tube segment 1 is placed inside the constant-temperature water jacket A, where the temperature is lower and it will not be stretched or deformed. Next, regarding the balloon shoulder 2, after pre-stretching, its shape, inner diameter, and other indicators have been basically stretched to the desired level, but its thickness is still too large. It needs to be stretched to thin the wall thickness, so it is urgent to heat this segment, but it cannot be overheated. In this invention, it is placed inside the heat insulation jacket B. The heat from the heating mold C heats the balloon shoulder 2 through heat transfer, while the heat insulation jacket B prevents the heat from the heating mold C from reaching the interior of the constant-temperature water jacket A. Example

[0028] First, connect the balloon to both ends of the electric stretching platform in the order shown in the diagram, apply a tension of 5N, and inflate it with a pressure of 20kPa, keeping both ends of the balloon sealed. Place the processed end of the balloon tightly against the end baffle, ensuring the processed tube bears a tension of 9N. Heat the heating mold to 120℃, then stretch the processed tube outwards by 30mm at a speed of 6mm / s. Immediately after stretching, retract the narrow neck section 3 of the balloon into the constant-temperature water jacket; the distance between the two ends of the tube should not change during this process.

[0029] Next, apply a tensile force of 1.5N to the balloon and inflate it with a pressure of 3kPa, keeping both ends of the balloon sealed. Place the narrow neck section 3 of the balloon completely inside the heating chamber, ensuring that the end of the narrow neck section is aligned with the boundary of the heating chamber. Heat the narrow neck section 3 to 120℃, then stretch it at a CNC tensile testing machine at a speed of 5mm / s on the left and 3mm / s on the right for 15 seconds, simultaneously performing blow molding on the narrow neck section 3. Immediately after stretching, retract the narrow neck section 3 into the constant-temperature water jacket; the distance between the two ends of the feed tube should not change during this process.

[0030] Next, rotate the balloon and connect it to both ends of the electric stretching platform in the order shown in the diagram. Apply a tension of 5N and inflate it with 20kPa of air pressure, keeping both ends of the balloon sealed. Place the processed end of the balloon tightly against the end baffle, ensuring that the processed tube bears a tension of 9N. Heat the heating mold to 120℃, then stretch the processed tube outward by 30mm at a speed of 6mm / s. Immediately after stretching, retract the narrow neck section 3 of the balloon into the constant temperature water jacket. The distance between the two ends of the tube should not change during this process.

[0031] Finally, apply a tensile force of 1.5 N to the balloon and inflate it with a pressure of 3 kPa, keeping both ends of the balloon sealed. Place the balloon's narrow neck segment 3 completely inside the heating chamber, ensuring that the boundary between its end and the boundary of the heating chamber is aligned with the boundary of the heating chamber. Heat the balloon's narrow neck segment 3 to 120°C, then stretch it using a CNC tensile testing machine at a speed of 5.5 mm / s on the left and 3 mm / s on the right. Simultaneously, blow-mold the balloon's narrow neck segment 3 while stretching for 15 seconds. Immediately after stretching, retract the balloon's narrow neck segment 3 back into the constant-temperature water jacket. Example

[0032] First, connect the balloon to both ends of the electric stretching platform in the order shown in the diagram, apply a tension of 6N, and inflate it with a pressure of 25kPa, keeping both ends of the balloon sealed. Place the processed end of the balloon tightly against the end baffle, ensuring the processed tube bears a tension of 10N. Heat the heating mold to 145℃, then stretch the processed tube outwards by 30mm at a speed of 6mm / s. Immediately after stretching, retract the narrow neck section 3 of the balloon into the constant-temperature water jacket; the distance between the two ends of the tube should not change during this process.

[0033] Next, apply a tensile force of 1.5N to the balloon and inflate it with a pressure of 3kPa, keeping both ends of the balloon sealed. Place the narrow neck section 3 of the balloon completely inside the heating chamber, ensuring that the boundary between its end and the boundary of the heating chamber is aligned with the boundary of the heating chamber. Heat the narrow neck section 3 to 145℃, then stretch it at a CNC tensile testing machine at a speed of 4mm / s on the left and 3mm / s on the right for 12 seconds, simultaneously performing blow molding on the narrow neck section 3. Immediately after stretching, retract the narrow neck section 3 into the constant-temperature water jacket; the distance between the two ends of the feed tube should not change during this process.

[0034] Next, rotate the balloon and connect it to both ends of the electric stretching platform in the order shown in the diagram. Apply a tension of 6N and inflate it with 25kPa of air pressure, keeping both ends of the balloon sealed. Place the processed end of the balloon tightly against the end baffle, ensuring that the processed tube bears a tension of 9N. Heat the heating mold to 145℃, then stretch the processed tube outward by 30mm at a speed of 6mm / s. Immediately after stretching, retract the narrow neck section 3 of the balloon into the constant temperature water jacket. The distance between the two ends of the tube should not change during this process.

[0035] Finally, apply a tensile force of 1.5 N to the balloon and inflate it with a pressure of 3 kPa, keeping both ends of the balloon sealed. Place the balloon's narrow neck segment 3 completely inside the heating chamber, ensuring that the boundary between its end and the boundary of the heating chamber is aligned with the boundary of the heating chamber. Heat the balloon's narrow neck segment 3 to 145°C, then stretch it using a CNC tensile testing machine at a speed of 4.5 mm / s on the left and 3 mm / s on the right for 12 seconds. Simultaneously, blow-mold the balloon's narrow neck segment 3. Immediately after stretching, retract the balloon's narrow neck segment 3 back into the constant-temperature water jacket. Example

[0036] First, connect the balloon to both ends of the electric stretching platform in the order shown in the diagram, apply a tension of 8N, and inflate it with air pressure of 30kPa, keeping both ends of the balloon sealed. Place the processed end of the balloon tightly against the end baffle, ensuring the processed tube bears a tension of 10N. Heat the heating mold to 180℃, then stretch the processed tube outwards by 30mm at a speed of 5mm / s. Immediately after stretching, retract the narrow neck section 3 of the balloon into the constant-temperature water jacket; the distance between the two ends of the tube should not change during this process.

[0037] Next, apply a tensile force of 1.5N to the balloon and inflate it with a pressure of 3kPa, keeping both ends of the balloon sealed. Place the narrow neck section 3 of the balloon completely inside the heating chamber, ensuring that the boundary between its end and the boundary of the heating chamber is aligned with the boundary of the heating chamber. Heat the narrow neck section 3 to 180°C, then stretch it using a CNC tensile testing machine at a speed of 3mm / s on the left and 2mm / s on the right for 8 seconds, while simultaneously performing blow molding on the narrow neck section 3. Immediately after stretching, retract the narrow neck section 3 into the constant-temperature water jacket; the distance between the two ends of the feed tube should not change during this process.

[0038] Next, rotate the balloon and connect it to both ends of the electric stretching platform in the order shown in the diagram. Apply a tension of 8N and inflate it with 30kPa of air pressure, keeping both ends of the balloon sealed. Place the processed end of the balloon tightly against the end baffle, ensuring the processed tube bears a tension of 7N. Heat the heating mold to 180℃, then stretch the processed tube outward by 30mm at a speed of 5mm / s. Immediately after stretching, return the narrow neck section of the balloon to the constant-temperature water jacket. The distance between the two ends of the tube should not change during this process.

[0039] Finally, apply a tensile force of 1.5 N to the balloon and inflate it with a pressure of 3 kPa, keeping both ends of the balloon sealed. Place the balloon's narrow neck segment 3 completely inside the heating chamber, ensuring that the boundary between its end and the boundary of the heating chamber is aligned with the boundary of the heating chamber. Heat the balloon's narrow neck segment 3 to 180°C, then stretch it using a CNC tensile testing machine at a speed of 3.5 mm / s on the left and 2 mm / s on the right for 8 seconds. Simultaneously, blow-mold the balloon's narrow neck segment 3. Immediately after stretching, retract the balloon's narrow neck segment 3 back into the constant-temperature water jacket. Example

[0040] The balloon is stretched simultaneously at both ends, connected to both ends of an electric stretching platform, subjected to a 6N tension force, and inflated with 25kPa of air pressure while maintaining the balloon's ends sealed. The processed end of the balloon is pressed tightly against the end baffle, and the processed side tube is subjected to a 10N tension force. The heating mold is heated to 145℃, and then the processed end tube is stretched outward by 30mm at a speed of 6mm / s. Next, a 1.5N tension force is applied to the balloon, and it is inflated with 3kPa of air pressure while maintaining the balloon's ends sealed. The narrow neck section 3 of the balloon is completely placed inside the heating chamber, with the end and the boundary of the narrow neck section 3 aligned with the boundary of the heating chamber. The narrow neck section 3 of the balloon is heated to 145℃, and then stretched at a speed of 4mm / s on the left and 4mm / s on the right for 12s, while simultaneously blow molding the narrow neck section 3 of the balloon.

[0041] The performance of the balloons in Examples 1-3 and the comparative examples is shown in the table below:

[0042] Table 1

[0043] Table 1 shows that the balloons produced using this invention have a higher pass rate for both the shoulder and the neck section, and their performance is more stable. This process can reduce the end thickness by 70%, the thickness of the neck section 3 by 60%, and the diameter of the neck section 3 by 50%, to meet the requirements for subsequent welding and folding / gripping of the large TPU balloon.

[0044] The foregoing has shown and described the basic principles, main features, and characteristics of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A process for stretching and forming the end of a large-size balloon, characterized in that, Includes the following steps: S1) Place the initially stretched balloon into the restretching mold. The straight section (1) of the balloon is placed in the constant temperature water jacket (A), the shoulder (2) of the balloon is placed in the heat insulation jacket (B), and the narrow neck section (3) of the balloon is placed in the heating mold (C). The restretching mold includes the constant temperature water jacket (A), the heat insulation jacket (B), and the heating mold (C) from left to right. S2) Connect both ends of the material tube to a CNC tensile testing machine. One end of the material tube is closed and the other end is connected to the air source. After the air is filled into the balloon, both ends of the balloon are closed and pressure is maintained. S3) Keep the temperature of the constant temperature water jacket (A) at T1, heat the heating mold (C) to the temperature T2, and then stretch the processing end tube outward at a speed of V1. After stretching, immediately retract the ball bag neck section (3) into the constant temperature water jacket (A). S4) When the balloon is in the ventilated state, the narrow neck segment (3) of the balloon is completely placed inside the heating chamber of the heating mold (C); S5) Heat the balloon neck section (3) to temperature T2, and then stretch it at speeds of V2 on the left and V3 on the right of the CNC tensile machine for a stretching time of t1. At the same time as stretching, blow molding is performed on the balloon neck section (3). After stretching, the balloon neck section (3) is immediately returned to the constant temperature water jacket (A). S6) Reverse the balloon direction and repeat steps S1), S2), S3), and S4). S7) When the balloon is in the ventilated state, heat the balloon neck section (3) to T2, and then stretch it at the speed of V4 on the left and V3 on the right of the CNC tensile machine for a stretching time of t1. At the same time as stretching, blow molding is performed on the balloon neck section (3). After stretching, the balloon neck section (3) is immediately returned to the constant temperature water jacket (A) at a speed of V4 greater than V2. S8), remove the balloon; Among them, the value range of V1 is 5mm / s to 10mm / s, the value range of V2 is 3mm / s to 5mm / s, the value range of V3 is 2mm / s to 4mm / s, and the value range of V4 is 3.5mm / s to 5.5mm / s; the temperature T1 of the constant temperature water jacket (A) is 10℃ to 18℃, and the temperature T2 of the heating mold is 120℃ to 180℃.

2. The large-size balloon end stretching forming process according to claim 1, characterized in that: The inner diameter of the constant temperature water jacket (A) is 2mm larger than the standard diameter of the balloon, and its length is 30cm longer than the standard length of the balloon.

3. The large-size balloon end stretching forming process according to claim 1, characterized in that: In step S2), the CNC tensile testing machine applies a tensile force of 5N to 8N to both ends of the balloon, and the balloon is filled with air pressure of 15kPa to 30kPa.

4. The large-size balloon end stretching forming process according to claim 1, characterized in that: In step S4), the boundary between the shoulder (2) and the neck (3) of the balloon should be at the same position as the boundary of the heating cavity of the heating mold (C).

5. The large-size balloon end stretching forming process according to claim 1, characterized in that: In steps S5) and S7), when the slender neck section (3) of the balloon retracts into the constant temperature water jacket (A), the CNC tensioning machines at both ends of the balloon move synchronously to ensure that the distance between the two ends of the material tube does not change.

6. The large-size balloon end stretching forming process according to claim 1, characterized in that: The stretching time t1 ranges from 8s to 18s.

7. The large-size balloon end stretching forming process according to claim 1, characterized in that: The axis of the CNC tensile testing machine coincides with the axis of the balloon and is arranged in a horizontal direction.

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