JP7542177B2 - Manufacturing method of syringe with needle - Google Patents

Description

The present invention relates to a method for manufacturing a syringe with a needle.

Conventionally, some relatively small-capacity syringes used for administering insulin, etc., have a needle tube that is directly attached to the syringe (outer barrel) without a needle hub. In such needle syringes, the needle tube is generally attached to the syringe using an adhesive.

However, when adhesive is used to join the needle and the syringe, there is a problem in that the adhesive components may dissolve or leak into the medicinal solution, which may have adverse effects on the living body to which the medicinal solution is administered. In particular, in the case of a prefilled syringe, in which the medicinal solution is filled in advance, the adhesive is in contact with the medicinal solution for a long period of time, and the amount of the adhesive components dissolving or leaking into the medicinal solution is also large, so a joining method that replaces adhesives was required.

In response to this, a method has been proposed for manufacturing a syringe with a needle by fixing (holding) the needle to a mold for injection molding the syringe and forming the syringe integrally with the needle, i.e., by insert molding (see, for example, Patent Document 1). Insert molding allows the needle and syringe to be joined without using adhesive, which makes it possible to solve the problem of adhesive components leaching or leaking into the drug solution, etc.

JP 2018-61856 A

However, the method described in Patent Document 1 fixes the needle tube to the mold by clamping it with two chuck members, which requires a chuck member that can be moved relative to the mold and a mechanism for moving the chuck member, resulting in a complex configuration of the mold and its peripheral equipment, and increased manufacturing costs.

In view of the above circumstances, the present invention aims to provide a method for manufacturing a needle-equipped syringe that can reduce manufacturing costs.

The method for manufacturing a needle-equipped syringe of the present invention is characterized by comprising the steps of: a first step of attaching a holder that partially covers the outer peripheral surface of a needle tube in the axial direction to the base end side of the needle tube having a needle tip at its tip; a second step of inserting the tip side of the needle tube into the tip side needle tube receiving section provided in the first mold while the syringe mold is open and is composed of a first mold and a second mold that are abutted against each other, and engaging the tip of the holder with the tip side holder engaging section provided on the inlet side of the tip side needle tube receiving section; a third step of closing the syringe mold and placing a part of the holder in the axial direction in the cavity of the syringe mold; and a fourth step of filling the cavity of the syringe mold with resin to form a syringe.

The method for manufacturing a needle-equipped syringe of the present invention makes it possible to fix the needle to the syringe mold by utilizing the stepped tip of the needle with the holder attached. This eliminates the need to complicate the configuration of the syringe mold and its peripheral devices, or to machine the needle housing with high precision, and allows the needle-equipped syringe to be manufactured at low cost by insert molding.

In addition, according to the manufacturing method of the needle syringe of the present invention, it is possible to insert mold the needle tube at low cost by fixing it via a holder, even for the small diameter needle tube that is less painful, which is in high demand with the spread of prefilled syringes for self-administration. In addition, since there is no need to directly contact the needle tube with a syringe mold or chuck member, it is possible to prevent scratches, deformation, etc. on the needle tube.

In addition, in the method for manufacturing a needle-equipped syringe of the present invention, it is preferable that in the third step, the base end surface of the holder is abutted against the second mold.

This allows the needle tube with the holder attached to be stably held between the first and second dies without complicating the configuration of the syringe mold and its peripheral equipment. In addition, it is possible to simplify or omit the locking structure of the base end of the holder, which is to be provided at the tip of the core pin (core) in the second mold, and therefore the volume of the dead space (recess where the tip surface of the gasket does not abut) that occurs inside the syringe can be reduced.

In addition, in the manufacturing method of the needle-equipped syringe of the present invention, in the third step, it is preferable that the base end of the holder is engaged with a base end holder engaging portion provided on the second mold.

This allows the needle tube with the holder attached to be stably held by engaging with both the first and second molds without complicating the configuration of the syringe mold and its peripheral equipment.

In addition, in the manufacturing method of the needle-equipped syringe of the present invention, it is preferable that in the first step, the holder is welded to the needle tube.

This allows the holder to be attached to the needle tube more reliably than other joining methods such as insert molding, welding, or pressure welding.

In addition, the method for manufacturing a needle-equipped syringe of the present invention preferably includes a preliminary step of forming a rough surface on the outer peripheral surface of the holder prior to the second step.

This increases the contact area with the resin that makes up the syringe due to the unevenness of the surface and creates an anchor effect, improving the bond and strength of the connection between the holder and the syringe.

In addition, in the manufacturing method of the needle-equipped syringe of the present invention, in the first step, it is also preferable to form the holder by filling the cavity of the holder mold with resin while placing a part of the needle tube in the cavity of the holder mold.

According to this, insert molding is performed in two stages, so it is possible to reduce costs compared to when insert molding the syringe and needle tube at the same time, and it is possible to perform insert molding on a thinner needle tube. Specifically, since the holder is much smaller than the syringe and does not require a complex shape, the holder mold is also smaller and simpler than the syringe mold, and molding conditions such as injection pressure and pressure holding conditions during insert molding are also relaxed. Therefore, even a holder mold that directly fixes a thin needle tube can be manufactured with relatively low processing accuracy, and the first stage of insert molding, in which only the holder is formed integrally with the needle tube, is simple. And, as described above, by forming the syringe integrally with the needle tube to which the holder is attached, the second stage of insert molding is low cost and it is possible to insert mold a thinner needle tube together with the syringe.

In addition, the method for manufacturing a needle-equipped syringe of the present invention preferably includes a preliminary step of forming a rough surface on the outer circumferential surface of the needle tube prior to the first step.

This increases the contact area with the resin that makes up the holder due to the unevenness of the surface and creates an anchor effect, improving the connection and strength of the connection between the needle tube and the holder.

The method for manufacturing a syringe with a needle of the present invention has the excellent effect of reducing manufacturing costs.

1A is a front view of a syringe with a needle according to an embodiment of the present invention, and FIG. 1A and 1B are schematic diagrams showing a method for manufacturing a syringe with a needle. 1A to 1C are schematic diagrams illustrating a method for manufacturing a syringe with a needle. 1A to 1C are schematic diagrams illustrating a method for manufacturing a syringe with a needle. 1A to 1C are schematic diagrams illustrating a method for manufacturing a syringe with a needle. 1A to 1C are schematic diagrams showing a method for attaching a holder to a needle tube by insert molding. 13A to 13C are schematic diagrams showing a modified example of the method for manufacturing a syringe with a needle. 13A to 13C are schematic diagrams showing a modified example of the method for manufacturing a syringe with a needle.

The following describes an embodiment of the present invention with reference to the attached drawings. First, the configuration of a needle-equipped syringe 1 will be described. Figure 1A is a front view of a needle-equipped syringe 1 according to one embodiment of the present invention, and Figure 1B is a cross-sectional view taken along line I-I in Figure 1A.

The needle syringe 1 is used to inject a medicinal liquid or the like into a living body by piercing the surface of the skin with the needle tip. As shown in Figures 1A and 1B, the needle syringe 1 includes a needle tube 11 having a needle tip 11A at its tip that can pierce a living body, a holder 12 attached to the base end 11B side of the needle tube 11 and partially covering the outer circumferential surface of the needle tube 11 in the axial direction, and a syringe (outer tube) 14 joined by insert molding to the needle tube 11 (needle tube with holder 13) to which the holder 12 is attached.

The needle tube 11 is the part that is punctured into the living body by the needle tip 11A as described above. A blade surface is formed at the tip of the needle tube 11 to make the needle tip 11A sharp. The size of the needle tube 11 is not particularly limited, and for example, a 16 to 33 gauge (outer diameter: 1.7 to 0.2 mm) specified in ISO 9626 can be used.

In this embodiment, stainless steel (SUS304) is used as the material for the needle tube 11, but the material for the needle tube 11 is not limited to this, and other metals such as titanium alloys can be used. In addition, in this embodiment, the outer diameter of the needle tube 11 is approximately constant, but the outer diameter of the needle tube 11 may be changed in the axial direction, for example by making the outer diameter on the needle tip 11A side smaller than the base end 11B side.

In addition, in this embodiment, the cross-sectional shape of the needle tube 11 is circular, but the cross-sectional shape of the needle tube 11 may be, for example, polygonal. In addition, the surface of the needle tube 11 may be coated with a fluororesin or the like to reduce friction with the skin when puncturing.

The holder 12 is the part that is engaged with the mold during insert molding, and is also the part that is joined to the syringe 14. In this embodiment, the holder 12 is attached to the needle tube 11 in advance to form a needle tube with holder 13 that has a portion with a larger diameter than the needle tube 11, and the syringe 14 is insert molded integrally with this needle tube with holder 13, making it possible to manufacture the needle-equipped syringe 1 at low cost without complicating the mold and its peripheral equipment.

The holder 12 is disposed on the base end 11B side of the needle tube 11 and is configured in a cylindrical shape that partially covers the outer peripheral surface of the needle tube 11 in the axial direction. In this embodiment, the holder 12 is attached (joined) to the needle tube 11 by welding or insert molding.

In this embodiment, the tip 12A and base 12B of the holder 12 are the parts that are engaged with the mold when the needle tube with holder 13 and the syringe 14 are insert molded, and the intermediate portion 12C between the tip 12A and base 12B is the part that is joined to the syringe 14. Therefore, in the needle syringe 1, the tip 12A and base 12B of the holder 12 are exposed from the syringe 14.

In other words, in this embodiment, the needle syringe 1 is configured so that the tip 12A and base 12B of the holder 12 are exposed from the syringe 14, which allows the needle tube 11 to be fixed to the mold by engaging the tip 12A and base 12B of the holder 12. As a result, it is possible to manufacture the needle syringe 1 at low cost without complicating the mold and its peripheral equipment.

The material of the holder 12 is not particularly limited, and appropriate materials such as various metals and various resins can be used. However, when the holder 12 is made of metal, it is preferable that the material of the holder 12 is the same or the same type of metal as the needle tube 11 from the viewpoint of weldability with the needle tube 11. Also, when the holder 12 is made of resin, it is preferable that the material of the holder 12 is the same or the same type of resin as the syringe 14 from the viewpoint of joinability with the syringe 14 by insert molding.

In this embodiment, the holder 12 is cylindrical, but the holder 12 may have a cross section that is, for example, C-shaped, U-shaped, or U-shaped. In this embodiment, the outer shape of the holder 12 is cylindrical, but the outer shape of the holder 12 may be, for example, an elliptical cylinder, a rectangular cylinder, a truncated cone, or a truncated pyramid, or may have a stepped portion or an appropriate uneven shape on the outer circumferential surface.

The syringe 14 is a part that contains a medicinal liquid or the like inside, and is configured as a cylinder with a bottom. A protrusion 14A that protrudes toward the tip side is provided at the bottom, which is the tip side of the syringe 14, and the needle tube with holder 13 is joined to this protrusion 14A. A number of ribs are provided on the outer periphery of the protrusion 14A to prevent the occurrence of sink marks, voids, etc. during injection molding while ensuring the strength of the protrusion 14A. In addition, a cylindrical fitting portion 14B is provided at the tip side of the protrusion 14A. This fitting portion 14B is a part that fits with a cap (not shown) that protects the needle tube 11.

The inside of the needle tube 11, which is joined to the protruding portion 14A via the holder 12, is connected to the inside of the syringe 14. The base end side of the syringe 14 is an opening for inserting a plunger (not shown). A ring-shaped flange 14C that protrudes outward is provided on the outer periphery of this opening. The shape of each part of the syringe 14 is not particularly limited, and any shape can be adopted.

The material of the syringe 14 is not particularly limited, but is preferably a transparent or translucent resin that allows the medicinal liquid contained therein to be visually observed. In this embodiment, the syringe 14 is made of cyclic polyolefin (COP), but the syringe may also be made of, for example, cyclic olefin copolymer (COC) or polypropylene (PP).

Next, a method for manufacturing the needle syringe 1 will be described. Figures 2A and B and Figures 3 to 5 are schematic diagrams showing a method for manufacturing the needle syringe 1. First, a case in which the metal holder 12 is attached (joined) to the needle tube 11 by welding will be described.

In the first step, the holder 12 is attached to the needle tube 11. Specifically, as shown in FIG. 2A, the needle tube 11 is first inserted into the cylindrical holder 12, and the holder 12 is placed at a predetermined position on the base end 11B side of the needle tube 11 (in this embodiment, a position where the base end 11B side of the needle tube 11 slightly protrudes from the holder 12). The needle tube 11 and the holder 12 are then fixed with an appropriate jig, and the distal end surface 12A1 and the proximal end surface 12B1 of the holder 12 are irradiated with laser light L to weld the holder 12 to the needle tube 11. As a result, as shown in FIG. 2B, a molten portion 12D is formed at the welded portion, and a needle tube with holder 13 in which the needle tube 11 and the holder 12 are integrated is obtained.

In this embodiment, laser welding is used because the needle tube 11 has a relatively small diameter, allowing fine welding, but other welding methods such as arc welding, electron beam welding, or brazing may also be used. In addition, it is preferable to perform welding around the entire circumference of the needle tube 11 to ensure the airtightness of the needle syringe 1.

It is preferable to form a rough surface (provide an uneven shape) on the outer peripheral surface of the holder 12 in advance by, for example, blasting in a preliminary step prior to the first step. By providing a rough surface on the outer peripheral surface of the holder 12, the unevenness of the surface increases the contact area with the resin constituting the syringe 14 and creates an anchor effect, making it possible to improve the bondability and bond strength with the resin constituting the syringe 14. In this case, the surface roughness Ra of the rough surface is preferably 0.2 μm or more, and more preferably in the range of 0.2 μm to 2.0 μm.

This preliminary step may be performed before the first step, or after the first step and before the second step described below. The rough surface may be provided over the entire holder 12, or may be provided partially, for example only on the middle portion 12C. The outer peripheral surface of the holder 12 may be roughened by a method other than blasting, such as etching.

Next, in the second step, as shown in FIG. 3, the needle tube with holder 13 is engaged with the syringe mold 20 that forms the syringe 14. In this embodiment, a horizontal molding machine that opens and closes the syringe mold 20 in the horizontal direction is used, and the first mold 21 that forms the tip end of the syringe 14 is the movable mold, and the second mold 22 that forms the base end of the syringe 14 is the fixed mold.

The first mold 21 is provided with a cavity 23 that forms the periphery of the fitting portion 14B, a tip-side needle tube accommodating portion 24 that accommodates the needle tip 11A side of the needle tube 11, a tip-side holder locking portion 24A to which the tip portion 12A of the holder 12 is locked, and a tip-side tapered portion 24B that guides the tip portion 12A of the holder 12 to the tip-side holder locking portion 24A.

The tip side needle tube housing 24 is a deep hole with a circular cross section drilled from the cavity 23 side, and has an inner diameter set to create an appropriate gap between it and the outer circumferential surface of the needle tube 11. The tip side holder locking portion 24A is provided with an expanded diameter on the inlet side (cavity 23 side) of the tip side needle tube housing 24, and is set to an inner diameter that fits the holder 12, or an inner diameter that creates a gap between it and the outer circumferential surface of the holder 12 to prevent resin from flowing in. The tip side tapered portion 24B is provided so that it gradually expands in diameter from the tip side holder locking portion 24A toward the cavity 23 side.

The second mold 22 includes a body portion 25 that forms the main portion of the syringe 14, a slide portion 26 that forms the periphery of the protruding portion 14A of the syringe 14, and a core pin 27 that forms the hollow shape of the syringe 14. These are combined to form a cavity 23 that forms the base end side of the syringe 14. In addition, the tip of the core pin 27 is provided with a base end needle tube housing portion 28 that houses the base end 11B side of the needle tube 11, a base end holder locking portion 28A to which the base end portion 12B of the holder 12 is locked, and a base end taper portion 28B that guides the base end portion 12B of the holder 12 to the base end holder locking portion 28A.

The base end needle tube housing 28, like the tip end needle tube housing 24, is a hole with a circular cross section drilled from the cavity 23 side, and is set to an inner diameter that creates an appropriate gap between the outer circumferential surface of the needle tube 11. Similarly, the base end holder locking portion 28A is provided with an expanded diameter on the inlet side (cavity 23 side) of the base end needle tube housing 28, and is set to an inner diameter that fits the holder 12, or an inner diameter that creates a gap between the outer circumferential surface of the holder 12 that prevents resin from flowing in. The base end taper portion 28B is provided so that it gradually expands in diameter from the base end holder locking portion 28A toward the cavity 23 side.

Specifically, in the second step, with the syringe mold 20 open, the needle tip 11A side of the needle tube 11 is inserted into the tip needle tube housing portion 24 of the first mold 21, and the tip portion 12A of the holder 12 is inserted into the tip holder locking portion 24A and locked. As described above, the tip holder locking portion 24A is set to an inner diameter that fits the holder 12 or an inner diameter that creates a relatively small gap. In addition, the tip portion 12A of the holder 12 is located in the middle part in the axial direction of the holder-attached needle tube 13, i.e., near the center of gravity.

Therefore, even in a horizontal molding machine, the tip 12A of the holder 12 can be stably locked to the tip holder locking portion 24A simply by inserting the tip 12A into the tip holder locking portion 24A. In addition, the tip tapered portion 24B guides the tip 12A of the holder 12 to a position that is approximately concentric with the tip holder locking portion 24A, making it easy to insert the tip 12A into the tip holder locking portion 24A.

The depth of the tip side needle tube housing 24 is set so that the needle tip 11A of the needle tube 11 does not contact the bottom surface 24C of the tip side needle tube housing 24 when the tip surface 12A1 of the holder 12 is in contact with the bottom surface 24A1 (step surface) of the tip side holder locking portion 24A. Therefore, the holder-attached needle tube 13 is positioned axially relative to the first mold 21 by abutting the tip surface 12A1 of the holder 12 against the bottom surface 24A1 of the tip side holder locking portion 24A.

The inner diameter of the tip side needle tube housing 24 is set relatively large compared to the outer diameter of the needle tube 11 because the inflow of resin is prevented at the tip side holder locking portion 24A. In other words, the tip side needle tube housing 24 is configured so that the blade surface of the needle tube 11 is unlikely to come into contact with it when the tip portion 12A of the holder 12 is locked to the tip side holder locking portion 24A, and this prevents scratches, deformation, etc. from occurring on the needle tip 11A side of the needle tube 11 in this embodiment.

Next, in the third step, the first mold 21 is moved toward the second mold 22, and as shown in FIG. 4, the first mold 21 is brought into contact with the second mold 22 to close the cavity 23 (i.e., the syringe mold 20 is closed). At this time, the portion of the needle tube 11 that protrudes beyond the holder 12 on the base end 11B side is accommodated in the base end needle tube accommodation portion 28, and the base end portion 12B of the holder 12 is accommodated and locked in the base end holder locking portion 28A. In addition, the base end surface 12B1 of the holder 12 comes into contact with the bottom surface 28A1 (step surface) of the base end holder locking portion 28A, and the needle tube 13 with holder is clamped between the first mold 21 and the second mold 22.

Therefore, when the first mold 21 is abutted against the second mold 22 to close the cavity 23, the holder 12 is disposed in the cavity 23 at a portion in the axial direction, specifically, at the intermediate portion 12C excluding the distal end portion 12A accommodated in the distal end holder locking portion 24A and the proximal end portion 12B accommodated in the proximal end holder locking portion 28A. In addition, the distal end surface 12A1 of the holder 12 abuts against the bottom surface 24A1 of the distal end holder locking portion 24A, and the proximal end surface 12B1 of the holder 12 abuts against the bottom surface 28A1 of the proximal end holder locking portion 28A, so that the holder-attached needle tube 13 is positioned in the axial direction relative to the syringe mold 20.

The base end 12B of the holder 12 is guided by the base end taper portion 28B to a position that is approximately concentric with the base end holder locking portion 28A, so that by simply moving the first mold 21, the base end 12B can be locked to the base end holder locking portion 28A and the base end 11B side of the needle tube 11 can be housed in the base end needle tube housing portion 28.

The depth of the base end needle tube housing 28 is set to a depth such that the base end 11B of the needle tube 11 does not contact the bottom surface 28C when the base end surface 12B1 of the holder 12 is in contact with the bottom surface 28A1 of the base end holder locking portion 28A. The inner diameter of the base end needle tube housing 28 is set to be relatively large compared to the outer diameter of the needle tube 11. In other words, in this embodiment, scratches, deformations, etc. are prevented from occurring even on the base end 11B side of the needle tube 11.

Next, in the fourth step, the cavity 23 is filled with resin, and the syringe 14 is formed integrally with the holder-attached needle tube 13. The resin filled in the cavity 23 solidifies while enclosing the outer peripheral surface of the middle part 12C of the holder 12 placed in the cavity 23, thereby joining the holder-attached needle tube 13 to the syringe 14. In other words, the syringe 14 is formed in a state where it is partially joined to the holder 12 in the axial direction, in other words, where it is joined to a part of the holder 12 in the axial direction.

In addition, the tip 12A and base 12B of the holder 12, i.e., the portions housed within the tip holder locking portion 24A and base holder locking portion 28A, are not in contact with the resin, and are therefore exposed from the syringe 14 in the completed needle syringe 1.

Next, in the fifth step, as shown in FIG. 5, the syringe mold 20 is opened to release the needle-equipped syringe 1 that has been formed, and post-processing such as deburring is performed as necessary. Through the above steps, the needle-equipped syringe 1 is completed. Note that the state of the syringe mold 20 at the time of release shown in FIG. 5 is not necessarily accurate.

In this manner, in this embodiment, a holder 12 having a larger diameter than the needle tube 11 is attached to the needle tube 11 in advance to form a needle tube with holder 13, and the stepped portion of this needle tube with holder 13 (i.e., the tip end 12A and base end 12B of the holder 12) is utilized to fix (hold) the needle tube 11 to the syringe mold 20. This makes it possible to manufacture the needle-equipped syringe 1 at low cost without complicating the configuration of the syringe mold 20 and its peripheral equipment.

In addition, even thin needle tubes 11 of 30 gauge or more, which were previously difficult to insert mold, can now be stably fixed to the syringe mold 20 and insert molded integrally with the syringe 14. In addition, since the needle tube 11 can be fixed to the syringe mold 20 without directly contacting the syringe mold 20 or chuck member, etc., with the needle tube 11, it is possible to prevent scratches, deformation, etc., from occurring in the needle tube 11.

In addition, if the needle tube 11 is fixed directly to the syringe mold 20, the tip side needle tube housing 24, which is a small diameter deep hole, needs to be machined with high precision to an inner diameter that does not allow resin to flow into the gap with the needle tube 11. However, in this embodiment, the tip side holder locking portion 24A, which is a relatively large diameter shallow hole, can prevent resin from flowing in, so it is possible to reduce the machining precision of the tip side needle tube housing 24.

This reduces the manufacturing cost of the syringe mold 20. Also, by blocking the inflow of resin at the tip side holder locking portion 24A, the tip side needle tube housing portion 24 can be made relatively large in diameter, making it possible to prevent scratches, deformation, and the like of the needle tube caused by contact with the tip side needle tube housing portion 24. Furthermore, by configuring the tip side needle tube housing portion 24 to have a relatively large diameter, it becomes possible for one syringe mold 20 to accommodate needle tubes 11 of multiple sizes.

In addition, in this embodiment, the needle tube with holder 13 is supported first by the tip side holder locking portion 24A, so compared to the conventional technology in which the base end of the needle tube is supported first during insert molding, it is possible to configure the base end needle tube storage portion 28 and the base end side holder locking portion 28A shallower. This allows the recess 14D, which becomes dead space because the tip surface of the gasket does not abut when the needle syringe 1 is in use, to be configured shallower than in the past. In other words, in the needle syringe 1 of this embodiment, the amount of medicinal liquid remaining in the syringe 14 after administration of medicinal liquid or the like is less than in conventional syringes made by insert molding.

In this embodiment, the first mold 21 is the movable mold and the second mold 22 is the fixed mold, but the first mold 21 may be the fixed mold and the second mold 22 may be the movable mold. Also, in steps 2 to 5, a vertical molding machine in which the first mold 21 and the second mold 22 are arranged one above the other may be used. In this case, by arranging the first mold 21 on the lower side, the needle tube with holder 13 can be stably fixed to the first mold 21.

Next, a case where the resin holder 12 is attached (joined) to the needle tube 11 by insert molding in the first step will be described. Figures 6A to 6C are schematic diagrams showing a method for attaching the holder 12 to the needle tube 11 by insert molding. In this case, the first step involves insert molding in which the holder 12 is integrally formed with the needle tube 11 using a horizontal molding machine that opens and closes the holder mold 30 in the horizontal direction.

The holder mold 30 is composed of a third mold 31, which is a movable mold, and a fourth mold 32, which is a fixed mold. The third mold 31 is provided with a cavity 33 that forms the holder 12, and a needle tube locking portion 34 that locks the base end 11B side of the needle tube 11. The fourth mold 32 is provided with a holder needle tube accommodating portion 35 that accommodates the needle tip 11A side of the needle tube 11.

The needle tube locking portion 34 is a hole with a circular cross section drilled from the cavity 33 side, and is set to an inner diameter that fits the needle tube 11 or creates a gap between the needle tube 11 and the outer peripheral surface to prevent resin from flowing in. The holder needle tube storage portion 35 is a deep hole with a circular cross section drilled from the cavity 33 side (third mold side), and is set to an inner diameter that creates a gap between the needle tube 11 and the outer peripheral surface to prevent resin from flowing in. The depth of the holder needle tube storage portion 35 is set to a depth that does not allow the needle tip 11A of the needle tube 11 to contact the bottom surface 35A when the third mold 31 is abutted against the fourth mold 32 to close the cavity 33.

Specifically, in the first step in this case, as shown in FIG. 6A, the base end 11B side of the needle tube 11 is inserted into the needle tube locking portion 34 and locked in the open state of the holder mold 30. At this time, the base end 11B of the needle tube 11 abuts against the bottom surface 34A of the needle tube locking portion 34, so that the needle tube 11 is positioned in the axial direction. Next, the third mold 31 is moved toward the fourth mold 32, and as shown in FIG. 6B, the needle tip 11A side of the needle tube 11 is inserted into the holder needle tube storage portion 35 while the third mold 31 abuts against the fourth mold 32 to close the cavity 33 (i.e., the holder mold 30 is closed). Then, the cavity 33 is filled with resin, and the holder 12 is integrally formed with the needle tube 11.

The resin filled in the cavity 33 solidifies while partially enclosing the needle tube 11 in the axial direction, thereby joining the needle tube 11 to the holder 12. Finally, as shown in FIG. 6C, the holder mold 30 is opened to release the needle tube 13 with holder that has been formed, and post-processing such as deburring is performed as necessary. The above procedure completes the attachment of the holder 12 to the needle tube 11.

It is preferable to form a rough surface on the outer peripheral surface of the needle tube 11 in advance at the portion to be bonded to the resin constituting the holder 12 by, for example, subjecting the outer peripheral surface of the needle tube 11 to a blasting process in a preliminary process prior to the first process. By providing a rough surface on the outer peripheral surface of the needle tube 11, it is possible to increase the bond strength with the resin constituting the holder 12. In this case, the surface roughness Ra of the rough surface is preferably 0.2 μm or more, and more preferably in the range of 0.2 μm to 2.0 μm.

In this way, the holder 12 may be attached to the needle tube 11 by insert molding. The holder mold 30 is smaller and simpler in configuration than the syringe mold 20, and molding conditions such as injection pressure and pressure holding conditions during insert molding are also relaxed, so the required machining precision is lower than that of the syringe mold 20, making it possible to form the needle tube locking portion 34 and the holder needle tube accommodating portion 35 at low cost. In addition, the holder 12 can be attached to thin needle tubes 11 of 30 gauge or more by insert molding.

In other words, in this embodiment, by performing insert molding in two stages, it is possible to manufacture the needled syringe 1 at a lower cost than when the syringe 14 is integrally formed with the needle tube 11 in a single insert molding. In addition, it is also possible to manufacture needled syringes 1 with thin needle tubes 11 of 30 gauge or more, which have been difficult to manufacture in a single insert molding, by insert molding.

In addition, in the holder mold 30, the third mold 31 may be the fixed mold, and the fourth mold 32 may be the movable mold. Also, instead of a horizontal molding machine, a vertical molding machine in which the third mold 31 and the fourth mold 32 are arranged above and below may be used. In this case, by arranging the third mold 31 on the lower side, the needle tube 11 can be stably fixed to the third mold 31.

Next, a method for manufacturing the needle syringe 1 and a modified example of the needle syringe 1 will be described. Figures 7 and 8 are schematic diagrams showing a modified example of the method for manufacturing the needle syringe 1. In this example, in the third step, the base end 12B of the holder 12 is not engaged with the tip of the core pin 27, but the base end surface 12B1 of the holder 12 is brought into contact with the abutment surface 28D provided on the tip of the core pin 27. The other parts are the same as the example shown in Figures 1 to 6, so only the different parts will be described below.

In this example, as shown in Figures 7 and 8, only the base end needle tube housing 28 is provided at the tip of the core pin 27, and a circular abutment surface 28D is provided on the outer periphery of the opening (entrance) of this base end needle tube housing 28. Then, as shown in Figure 7, in the third step, the first mold 21 is abutted against the second mold 22, so that the base end surface 12B1 of the holder 12 abuts against the abutment surface 28D, and the holder-attached needle tube 13 is thereby clamped between the first mold 21 and the second mold 22.

In this embodiment, the tip portion 12A of the holder 12 is engaged with the tip side holder engaging portion 24A, so that the needle tube 13 with the holder can be stably held and positioned simply by abutting the base end surface 12B1 of the holder 12 against the abutment surface 28D. In this example, the base end portion 12B is placed in the cavity 23 together with the intermediate portion 12C of the holder 12 in the third step.

In the fourth step, the resin filled in the cavity 23 solidifies while encapsulating the intermediate portion 12C and the base end portion 12B of the holder 12 placed in the cavity 23, thereby joining the holder-attached needle tube 13 to the syringe 14. Then, as shown in FIG. 8, in the fifth step, the syringe mold 20 is opened and appropriate post-processing is performed as necessary to obtain the needle-attached syringe 1 of this example.

As shown in FIG. 8, the needle syringe 1 of this example has the outer peripheral surface of the intermediate portion 12C and the base end portion 12B of the holder 12 joined to the syringe 14. Therefore, in this example of the needle syringe 1, the tip portion 12A of the holder 12 is exposed from the syringe 14, and only the base end surface 12B1 of the base end portion 12B of the holder 12 is exposed from the syringe 14.

In this way, in the third step, instead of engaging the base end 12B of the holder 12 with the tip end of the core pin 27, the base end surface 12B1 of the holder 12 is only brought into contact with the abutment surface 28D of the tip end of the core pin 27, so that the depression 14D, which becomes dead space, can be made even shallower. In other words, according to this example, the amount of medicinal liquid remaining in the syringe 14 after administration of the medicinal liquid or the like can be further reduced.

In this example, the outer diameter of the abutment surface 28D is set to be approximately the same as the outer diameter of the holder 12, but the outer diameter of the abutment surface 28D may be larger or smaller than the outer diameter of the holder 12. Also, in this example, an appropriate tapered portion may be provided on the inlet side (cavity 23 side) of the base-end needle tube housing portion 28.

In addition, although not shown, only the base end needle tube housing 28 may be provided at the tip of the core pin 27 as in the example shown in Figures 7 and 8, and the base end 11B of the needle tube 11 may be abutted against the bottom surface 28C of the base end needle tube housing 28 in the third step. In this case, the base end needle tube housing 28 is configured to be shallower than the amount of protrusion from the holder 12 on the base end 11B side of the needle tube 11, and the resin can be brought into contact with the base end surface 12B1 of the holder 12, making it possible to configure the depression 14D, which becomes a dead space, even shallower. In addition, the base end needle tube housing 28 may be further omitted from the example shown in Figures 7 and 8, and the base end 11B (base end surface) of the needle tube 11 may be abutted against the tip surface of the core pin 27 in the third step.

The tip-side holder locking portion 24A may also be configured as a protrusion or rib that partially or intermittently abuts against the outer circumferential surface of the tip portion 12A of the holder 12 in the circumferential direction. In this case, it is sufficient to prevent the resin from flowing into the tip-side needle tube housing portion 24 between the tip surface 12A1 of the holder 12 and the protrusion or rib.

When the tip-side holder locking portion 24A is configured in this manner, in the completed needle-equipped syringe 1, the tip portion 12A of the holder 12 is partially exposed from the syringe 14. In other words, the needle-equipped syringe 1 is sufficient if at least the tip surface 12A1 of the tip portion 12A of the holder 12 is exposed from the syringe 14.

Similarly, the base end holder engaging portion 28A may be composed of a protrusion or rib that abuts partially or intermittently in the circumferential direction against the outer peripheral surface of the base end portion 12B of the holder 12.

In addition, when the second mold 22 is provided with the base end holder locking portion 28A, when the syringe mold 20 is closed, only one of the tip end surface 12A1 and the base end surface 12B1 of the holder 12 may be in contact with the bottom surface 24A1 of the tip end holder locking portion 24A or the bottom surface 28A1 of the base end holder locking portion 28A. In other words, the fixation of the holder-equipped needle tube 13 to the syringe mold 20 may have a predetermined degree of freedom in the axial direction.

The material of the holder 12 and the method of joining it to the needle tube 11 are not particularly limited, and in the first step, other known joining methods can be used depending on the material, such as welding, pressure welding, shrink fitting, or crimping. Even if the holder 12 is made of resin, a rough surface may be formed on the outer circumferential surface of the holder 12 before the second step. The needle tube with holder 13 may be configured so that the base end 11B side of the needle tube 11 does not protrude from the holder 12.

Although the embodiments of the present invention have been described above, the manufacturing method of the needle syringe and the needle syringe of the present invention are not limited to the above-mentioned embodiments, and various modifications can be made without departing from the gist of the present invention. For example, the shape and arrangement of each part of the needle syringe 1 are not limited to the shapes and arrangements shown in the present embodiment, and any shape and arrangement can be adopted. Similarly, the configurations of the syringe mold 20 and the holder mold 30 are not limited to the configurations shown in the present embodiment.

Furthermore, the actions and effects shown in the above-mentioned embodiments are merely a list of the most preferable actions and effects resulting from the present invention, and the actions and effects of the present invention are not limited to these.

REFERENCE SIGNS LIST 1 syringe with needle 11 needle tube 11A needle tip 11B base end of needle tube 12 holder 12A tip portion of holder 12A1 tip surface of holder 12B base end portion of holder 12B1 base surface of holder 13 needle tube with holder 14 syringe 20 mold for syringe 21 first mold 22 second mold 23 cavity of mold for syringe 24 tip side needle tube receiving portion 24A tip side holder locking portion 28A base side holder locking portion 30 mold for holder 33 cavity of mold for holder

Claims (7)

A first step of mounting a holder on a base end side of a needle tube having a needle tip at its tip, the holder partially covering an outer circumferential surface of the needle tube in an axial direction;
a second step of inserting a tip end of the needle into a tip end needle receiving portion provided in the first mold while opening a syringe mold including a first mold and a second mold that are brought into contact with each other, and locking a tip end of the holder into a tip end holder locking portion provided on an inlet side of the tip end needle receiving portion;
a third step of closing the syringe mold to place a portion of the holder in an axial direction within a cavity of the syringe mold;
a fourth step of filling a cavity of the syringe mold with a resin to form a syringe;
A method for manufacturing a syringe with a needle, comprising: 2. The method for manufacturing a needle-equipped syringe according to claim 1,
A method for manufacturing a syringe with a needle, wherein in the third step, the base end surface of the holder is abutted against the second mold. 3. The method for manufacturing a needle-equipped syringe according to claim 1, further comprising the steps of:
A method for manufacturing a syringe with a needle, wherein in the third step, the base end of the holder is engaged with a base end holder engaging portion provided on the second mold. The method for manufacturing a needle-equipped syringe according to any one of claims 1 to 3,
A method for manufacturing a needle-equipped syringe, wherein the first step includes welding the holder to the needle tube. The method for manufacturing a needle-equipped syringe according to any one of claims 1 to 4,
A method for manufacturing a syringe with a needle, comprising the steps of: forming a rough surface on the outer peripheral surface of the holder prior to the second step. The method for manufacturing a needle-equipped syringe according to any one of claims 1 to 3,
The method for manufacturing a syringe with a needle is characterized in that in the first step, a portion of the needle tube in the axial direction is positioned within the cavity of a mold for the holder, and resin is filled into the cavity of the mold for the holder to form the holder. 6. The method for manufacturing a needle-equipped syringe according to claim 5,
A method for manufacturing a needle-equipped syringe, comprising the steps of: forming a rough surface on an outer circumferential surface of the needle tube prior to the first step;

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