A thermoforming method for aseptic sampling

Abstract

The application discloses a kind of hot forming methods of sterile sampling piece, comprising the following steps: tail of self-sealing cap is inserted into needle shell;Self-sealing cap containing needle shell after assembly is placed in the edge of tip forming mold cavity, and die is closed;Mold and / or needle shell are heated, and needle shell made of polymer is softened, and during heating, forward force is applied to needle shell, and simultaneously rotates in one direction until completing setting seal;Die is opened, and sterile sampling piece is obtained after cooling.The application of some examples, by applying a certain time rotating forward force to needle, can ensure that the product is smooth in the thermoplastic forming process, and there is no flash and die line in the heat forming part of the product, the appearance is beautiful, the fixing effect is good, and the sealing effect of self-sealing cap is not affected;Openable and closable mold can be opened for demolding, and the demolding mode of product is flexible, and the application range is wide;Mold tip position is not easy to block, and even if blocking occurs, it is also convenient to clean.

Description

Technical Field

[0001] This invention belongs to the field of disposable pharmaceutical consumables, and specifically relates to a thermoforming method for irregularly shaped sampling parts. Background Technology

[0002] In the research and development and production of biopharmaceuticals and chemical pharmaceuticals, aseptic sampling is used to detect relevant indicators. Aseptic sampling devices mainly consist of a sampling support, a sampling needle, and a self-sealing cap. The assembly of the sampling needle and the self-sealing cap must ensure a leak-free seal, and the self-sealing cap must be firmly connected to the sampling needle to prevent detachment. During sampling, the sampling needle punctures the self-sealing cap and comes into contact with the sample liquid. If the sampling needle and self-sealing cap are not sealed properly or are not securely connected, sampling failure may occur, or even contamination of the entire sample liquid may result.

[0003] For ease of use, existing sampling devices generally consist of a needle body, with a needle tip at one end and a sampling tube at the other. The needle tip is sealed by a self-sealing cap. The needle body is typically bent from the middle, and the portion of the needle body coaxial with the needle tip is fixed by injection molding to form a sampling handle, allowing the needle tip to pierce the self-sealing cap for aseptic sampling. Therefore, the final sampling device is generally Y-shaped, with larger ends and a thinner middle section, resembling a dumbbell. The self-sealing cap is an asymmetrical dumbbell-shaped structure, thicker at both ends and thinner in the middle, with an opening at one end for inserting a metal needle. A protrusion at the opening of the self-sealing cap helps to secure the cap and enhance the seal when it is sealed to the sampling needle housing. The sampling needle housing has an annular structure with a uniform outer diameter. This annular structure accommodates the protrusion of the self-sealing cap, and the protrusion also supports the annular structure. After thermoforming, the inner wall of the originally uniform-diameter annular structure wraps around and tightly adheres to the protruding structure of the self-sealing cap and the thinner rod-shaped portion at the front end of the protruding structure, ultimately forming a tapered structure at the front end of the needle shell, thus achieving a sealing effect. The part of the aseptic sampling assembly that requires thermoforming is the needle shell at the front end of the sampling handle. Compared to the sampling needle handle and the head of the self-sealing cap, the final diameter of this part is the thinnest in the aseptic sampling assembly. This structure makes it impossible to manufacture this sampling component using a one-piece molded cavity method, otherwise demolding would be difficult.

[0004] To achieve better heat-melt fixing, the traditional method (DE102021111507A1) involves placing a plastic tubular blank on a mandrel and inserting it, along with the mandrel, into the cavity of a heated mold. The mold cavity has at least one feed channel and a mold channel connected to it. The blank is heated within the mold cavity, and the pointed end is reshaped to conform to the contours of the mold channel. Gas cooling is required during the molding process. This method is complex and costly.

[0005] Therefore, there is an urgent need for a method for aseptic sampling assembly molding to solve the aforementioned problems. Summary of the Invention

[0006] The purpose of this invention is to overcome at least one deficiency of the prior art and provide a thermoforming method for irregularly shaped sample parts.

[0007] The technical solution adopted in this invention is:

[0008] A thermoforming method for sterile sample parts includes the following steps:

[0009] S1) Insert the tail of the self-sealing cap into the needle housing;

[0010] S2) Place the assembled sampling needle shell with the self-sealing cap on the edge of the tip forming mold cavity and close the mold;

[0011] S3) Heat the mold and / or the sampling needle shell to soften the polymer-made needle shell. During the heating process, apply a forward force to the needle shell to move it forward while rotating it in one direction until the shape is set and sealed.

[0012] S4) Open the mold and cool to obtain sterile sample parts.

[0013] In some examples of thermoforming methods, the forming mold has a cavity that can be opened and closed along a direction perpendicular to the axis of the needle.

[0014] In some examples of thermoforming methods, the parting surface of the forming mold follows the principle that the axis of the needle is on the parting surface of the mold, or at least on one of the parting surfaces.

[0015] In some examples of thermoforming methods, the forming die has a temperature regulator.

[0016] In some examples of thermoforming methods, the mold cavity surface is coated with a release agent or subjected to a low-adhesion treatment.

[0017] In some examples of thermoforming methods, the rotational speed is uniform, linearly gradual, or non-linearly gradual.

[0018] In some examples of thermoforming methods, the rotation speed is 5 to 60 rpm.

[0019] In some examples of thermoforming methods, the heating temperature is above the heat distortion temperature of the needle shell but below its melting point.

[0020] In some examples of thermoforming methods, the thermoforming time for sample parts is between 10s and 50s.

[0021] In some examples of thermoforming methods, the magnitude of the force applied to the needle shell varies linearly or non-linearly.

[0022] In some examples of thermoforming methods, the distance the needle shell moves forward is greater than the length of the part to be thermoformed, but less than the total length of the thinner part in the middle of the sample.

[0023] In some examples of thermoforming methods, the needle shell is made of a thermoplastic material.

[0024] In some examples of thermoforming methods, the molding shrinkage rate of the thermoplastic material is less than 2%. The beneficial effects of this invention are:

[0025] In some embodiments of the present invention, by applying a force to the needle rotating forward for a certain period of time, it can be ensured that the surface of the thermoformed part of the product is smooth, without flash or parting lines, with a beautiful appearance, good fixing effect, and without affecting the sealing effect of the self-sealing cap.

[0026] In some embodiments of this invention, the tip-forming mold is an openable mold. Compared to traditional methods where the product can only be removed along the mold cavity opening direction, this solution allows the product to be removed along a direction perpendicular to the mold parting line after the mold is opened. This provides flexible product demolding and has a wide range of applications. The openable mold allows for demolding after opening, and the tip is less prone to clogging. Even if clogging occurs, it is easy to clean. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of some aseptic sampling parts before thermoforming in some examples of the present invention.

[0028] Figure 2 This is a schematic diagram of the structure of the aseptic sampling parts after thermoforming in some examples of the present invention.

[0029] Figure 3 These are photographs of aseptic sample parts after thermoforming, as examples of the present invention.

[0030] Figure label:

[0031] 1-Self-sealing cap, 2-Needle shell, 3-Sampling tube. Detailed Implementation

[0032] A thermoforming method for sterile sample parts includes the following steps:

[0033] S1) Insert the tail of the self-sealing cap into the needle housing;

[0034] S2) Place the assembled sampling needle shell with the self-sealing cap on the edge of the tip forming mold cavity and close the mold;

[0035] S3) Heat the mold and / or the sampling needle shell to soften the polymer-made needle shell. During the heating process, apply a forward force to the needle shell while rotating it in one direction until the shape is set and sealed.

[0036] S4) Open the mold and cool to obtain sterile sample parts.

[0037] Reference Figure 1 and Figure 2 The sampling component of this invention mainly includes a needle body, one end of which is a needle tip, and the tail end of the needle body is connected to the sampling tube 3. The needle tip is sealed by a self-sealing cap 1. The needle body is generally bent from the middle, and the part of the needle body coaxial with the needle tip is fixed by overmolding to form a sampling handle. The self-sealing cap 1 is a rod-shaped asymmetrical dumbbell structure that is thick at both ends and thin in the middle. One end has an opening structure for inserting a metal needle into the self-sealing cap 1. At one end of the opening structure of the self-sealing cap 1, there is a protrusion structure. This protrusion serves to fix the self-sealing cap 1 and strengthen the seal when the self-sealing cap 1 is sealed with the sampling needle shell 2. The sampling needle shell 2 has an annular structure with a uniform outer diameter. This annular structure is used to accommodate the protrusion structure of the self-sealing cap 1. At the same time, the protrusion structure of the self-sealing cap 1 supports the annular structure.

[0038] Figure 3 These are photographs of the aseptic sampling parts after thermoforming, as described in some examples of this invention. After thermoforming, the needle is sealed inside a transparent self-sealing cap, and a fine tapering structure is formed at the front end of the needle shell to seal the opening end of the self-sealing cap.

[0039] In some examples of thermoforming methods, the forming die has a cavity that can open and close along a direction perpendicular to the axis of the needle. This design makes it easier to achieve mold opening and closing.

[0040] In some examples of thermoforming methods, the parting surface of the forming mold follows the principle that the axis of the needle is on the parting surface of the mold, or at least on one of the parting surfaces.

[0041] Specifically, the molding die consists of an upper die and a lower die. The cavities of the upper and lower dies have the same shape, and the ends of the cavities gradually taper to form a frustum-shaped surface at the end of the needle shell, thus achieving a better sealing effect.

[0042] In some examples of thermoforming methods, the molding die has a temperature regulator. This allows for more convenient adjustment of the die temperature. Specifically, precise temperature control of the molding die can be achieved by inserting heating rods into the die and installing coolant pipes.

[0043] In some examples of thermoforming methods, the mold cavity surface is coated with a release agent or treated with a low-adhesion process. This effectively prevents the pin shell from adhering to the mold cavity surface, achieving better demolding and improving the appearance of the sample.

[0044] In some examples of thermoforming methods, the rotation speed is uniform, linearly gradually changing, or non-linearly gradually changing. The specific method of changing the rotation speed can be adjusted according to the needle shell material, temperature, etc. In a particular embodiment, the rotation speed is uniform.

[0045] There is no particular limitation on the rotation speed, as long as it does not damage the structure of the needle shell. In some thermoforming methods, the rotation speed is 5–60 rpm. In one specific embodiment, the rotation speed is 5 rpm; too low a speed can easily cause folding marks in the thermoformed part, resulting in an uneven thermoformed area. In another specific embodiment, the rotation speed is 60 rpm; too high a speed can easily cause the thermoformed part to be rough and uneven. In yet another specific example, the rotation speed is linearly gradual. The initial speed can be faster, for example, about 30–50 rpm, or even about 40–60 rpm; then the speed gradually decreases, for example, about 10–20 rpm, or even about 5–10 rpm, and the rotation stops before mold opening.

[0046] In some examples of thermoforming methods, the heating temperature is above the heat distortion temperature of the needle shell but below its melting point. This softens the needle shell more effectively, facilitating thermoforming, without causing it to melt and adversely affect the process. In one specific embodiment, the heating temperature is between 130°C and 150°C.

[0047] In some examples of thermoforming methods, the thermoforming time for the sample part is between 10 and 50 seconds, or 20 and 50 seconds. In one specific embodiment, the thermoforming time for the sample part is 20 seconds. A shorter thermoforming time can easily cause folding marks in the thermoformed area, resulting in an uneven surface. In another specific embodiment, the thermoforming time for the sample part is 50 seconds. An excessively long time can easily cause the thermoformed area to soften or even melt due to prolonged heating, leading to a rough and uneven surface.

[0048] In some examples of thermoforming methods, the magnitude of the force applied to the needle shell varies linearly or non-linearly. In one particular embodiment, the force applied to the needle shell is used to move the needle shell forward or to maintain the position of the needle shell after movement. In another particular embodiment, the force applied to the needle shell becomes 0 before mold opening.

[0049] In some examples of thermoforming methods, the needle shell moves forward a distance greater than the length of the part to be thermoformed, but less than the total length of the thinner section in the middle of the sample. In one specific embodiment, the needle shell moves forward a distance of 2–15 mm; in a further example, the needle shell moves forward a distance of 3–7 mm; and in an even further example, the needle shell moves forward 5.0 mm.

[0050] In some examples of thermoforming methods, the needle shell is made of a thermoplastic material. The thermoplastic material can be formed from a polyolefin material, such as a polypropylene-based or polyethylene-based elastomer or plasmon; it can also consist of a thermoplastic polyester elastomer or a material containing a thermoplastic polyester elastomer, such as PBT, TPEE; or it can consist of a thermoplastic polyamide elastomer or a material containing amide segments, such as PA, Pebax (Pebax® is a brand of the French company ARKEMA).

[0051] In one embodiment, the needle shell material is a thermoplastically processable polymer, including thermoplastic polyester elastomers, fluorinated elastomers, thermoplastic EPDM composites, styrene-based elastomers, polyolefin elastomers, flexible polyvinyl chloride (PVC), thermoplastic isoprene composites, any other thermoplastic elastomers, any blends thereof, or combinations thereof. In a particular embodiment, the needle shell material includes polypropylene, polyolefin elastomers, functional additives, or combinations thereof. In a more specific embodiment, the needle shell material includes polypropylene and functional color masterbatch.

[0052] In some examples of thermoforming methods, the molding shrinkage of the thermoplastic material is less than 2%. This is beneficial for obtaining sample parts with more stable dimensions and better uniformity.

[0053] In some embodiments of the thermoforming method, the polymer of the self-sealing cap comprises any conceivable thermoplastic and thermosetting material having a Shore hardness less than that of the needle shell. In one embodiment, the polymer of the self-sealing cap is a melt-processable polymer, including thermoplastic polyurethanes, thermosetting polyurethanes, fluorinated elastomers, copolymers of ethylene propylene diene monomer (EPDM), thermoplastic EPDM composites, styrene-based elastomers, polyolefin elastomers, flexible polyvinyl chloride (PVC), isoprene, thermoplastic isoprene composites, any other thermoplastic elastomers, any blends thereof, or combinations thereof. In one embodiment, the polymer of the self-sealing cap is a thermosetting elastomer polymer, including purified natural rubber, silicone rubber, nitrile rubber (NBR), butyl rubber (IIR), isoprene rubber (IR), polyurethane rubber, silicone rubber, any other thermosetting elastomers, any blends thereof, or combinations thereof. In a particular embodiment, the polymer of the self-sealing cap is platinum-cured silicone rubber.

[0054] The above is a further detailed description of the present invention and should not be considered as a limitation on the specific implementation of the present invention. For those skilled in the art, simple deductions or substitutions without departing from the concept of the present invention are all within the protection scope of the present invention.

Claims

1. A thermoforming method for sterile sample parts, comprising the following steps: S1) Insert the tail of the self-sealing cap into the sampling needle shell. There is a protruding structure at one end of the opening structure of the self-sealing cap. The sampling needle shell is an annular structure with an equal outer diameter. The annular structure is used to accommodate the protruding structure of the self-sealing cap. The protruding structure of the self-sealing cap supports the annular structure. S2) Place the assembled sampling needle shell with the self-sealing cap on the edge of the tip forming mold cavity, and close the mold. The forming mold has a mold cavity that opens and closes along the direction perpendicular to the axis of the needle tip. The end of the mold cavity gradually shrinks so that the end of the sampling needle shell forms a frustum-shaped surface. The parting surface of the forming mold follows the following principle: the axis of the needle tip is at least on one parting surface of the mold. S3) Heat the mold and / or the sampling needle shell to soften the sampling needle shell made of thermoplastic material. During the heating process, apply a forward force to the sampling needle shell to move it forward and rotate it in one direction until the shape is fixed and sealed. After thermoforming, the inner wall of the annular structure with the same diameter on the outer surface wraps around and tightly adheres to the protruding structure of the sealing cap and the thinner rod-shaped part at the front end of the protruding structure, forming the thinner end of the sampling needle shell. S4) Open the mold and cool to obtain sterile sample parts.

2. The thermoforming method according to claim 1, characterized in that, The molding die has a temperature regulator.

3. The thermoforming method according to claim 1 or 2, characterized in that, The mold cavity surface is coated with a release agent or treated with a low-adhesion process.

4. The thermoforming method according to claim 1, characterized in that, The rotational speed can be uniform, linearly gradual, or nonlinearly gradual.

5. The thermoforming method according to claim 1 or 4, characterized in that, The rotation speed is 5 to 60 rpm.

6. The thermoforming method according to claim 1, characterized in that, The heating temperature is above the heat deformation temperature of the sampling needle shell and below the melting point temperature.

7. The thermoforming method according to claim 1 or 6, characterized in that, The thermoforming time for the sampled parts is between 10s and 50s.

8. The thermoforming method according to claim 1, characterized in that, The molding shrinkage rate of the thermoplastic material is less than 2%.

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