Gasket for syringe, plunger with gasket for syringe including same, and barrel assembly for injection syringe

Abstract

A gasket 1 for a syringe is provided with a tubular body part 11, a closed distal end surface 12 positioned at the distal end of the tubular body part 11, a proximal end opening 13 positioned at the proximal end of the tubular body part 11, and a plunger fitting part 14 formed therein. The plunger fitting part 14 includes a gasket-side screw-threaded part 30 having one or more gasket-side screw threads 31 formed on the inner surface. A distal end-side inclination angle θ1, which is an inclination angle of the surface on the distal end side of each gasket-side screw thread 31 of the gasket-side screw-threaded part 30 with respect to the axis of the tubular body part 11, is larger than a proximal end-side inclination angle θ2, which is an inclination angle of the surface on the proximal end side of each gasket-side screw thread 31 of the gasket-side screw-threaded part 30 with respect to the axis of the tubular body part 11.

Description

Syringe gasket, plunger with syringe gasket, and barrel assembly for syringe

[0001] The present invention relates to a syringe gasket, a plunger with a syringe gasket, and a barrel assembly for a syringe.

[0002] Conventionally, in syringes with a small capacity used for insulin administration, vaccine administration, etc., a syringe barrel with a puncture needle fixed in advance may be used. For example, in FIG. 1A of Patent Document 1 (Japanese Patent Application Laid-Open No. 2023-526869), a syringe barrel is disclosed in which a piercing element (for example, a needle) (30) for injecting a therapeutic compound is attached to the tip of a barrel (20) as constituting a syringe (10). And a stopper (syringe gasket) (40) is housed in the barrel (20), and by moving a plunger (50) to which the stopper (40) is attached in the axial direction of the barrel (20), the drug (drug solution) in the barrel (20) can be discharged or the drug (drug solution) can be sucked into the barrel (20).

[0003] Japanese Patent Application Laid-Open No. 2023-526869

[0004] The inventors of the present invention have earnestly studied to further improve the performance of such a syringe gasket, a plunger with a syringe gasket, and a barrel assembly for a syringe. As a result, in particular, in the syringe gasket, it has been conceived that there is room for improvement in stabilizing the mounting (screwing) state with the plunger and improving the operability. Therefore, an object of the present invention is to provide a syringe gasket, a plunger with a syringe gasket, and a barrel assembly for a syringe, which can stabilize the mounting (screwing) state with the plunger and improve the operability in the syringe gasket.

[0005] The following is a syringe gasket that achieves the above objective: (1) A syringe gasket that is a cylindrical body with a closed tip and an open base, and is slidably housed in a liquid-tight and airtight state within a syringe barrel, wherein the syringe gasket is made of an elastic material and comprises a cylindrical body portion, a closed tip surface located at the tip of the cylindrical body portion, a base end opening located at the base end of the cylindrical body portion, and a plunger mounting portion formed inside, wherein the plunger mounting portion comprises a gasket-side threaded portion having one or more gasket-side threads formed on its inner surface, and the tip-side inclination angle, which is the inclination angle of the tip-side surface of the gasket-side threads of the gasket-side threaded portion with respect to the axis of the cylindrical body portion, is greater than the base-side inclination angle, which is the inclination angle of the base-side surface of the gasket-side threads of the gasket-side threaded portion with respect to the axis of the cylindrical body portion.

[0006] (2) In the syringe gasket described in (1) above, the gasket-side threads preferably have a tip-direction helical surface facing the tip and a base-direction helical surface facing the base, and over the entire length of the gasket-side threads, the tip-side inclination angle, which is the inclination angle of the tip-direction helical surface with respect to the axis of the cylindrical body, is greater than the base-side inclination angle, which is the inclination angle of the base-direction helical surface with respect to the axis of the cylindrical body. (3) In the syringe gasket described in (2) above, the gasket-side threads preferably have a helical top surface connecting the tip-direction helical surface and the base-direction helical surface. (4) In the syringe gasket described in (2) or (3) above, it is preferable that the inner edge of the tip-direction helical surface of the gasket-side thread is a gentler inner edge inclined surface or inner edge curved surface than the tip-side inclination angle, which is the inclination angle of the tip-direction helical surface with respect to the axis of the cylindrical body. (5) In the syringe gasket described in any of (1) to (4) above, it is preferable that the tip-side inclination angle is 60 to 80° and the base-side inclination angle is 55 to 75°. (6) In the syringe gasket described in any of (1) to (5) above, it is preferable that the tip-side inclination angle is 1 to 10° greater than the base-side inclination angle. (7) In the syringe gasket described in any of (1) to (6) above, the syringe gasket comprises a tip-side R-shaped portion provided between the tip-side surface of the gasket-side thread of the gasket-side screw portion and the inner surface of the cylindrical body portion, and a base-side R-shaped portion provided between the base-side surface of the gasket-side thread of the gasket-side screw portion and the inner surface of the cylindrical body portion, wherein the R diameter of the tip-side R-shaped portion is larger than the R diameter of the base-side R-shaped portion.

[0007] Furthermore, the following is a device that achieves the above objective: (8) A syringe gasketed plunger comprising a syringe gasket as described in any of (1) to (7) above, and a plunger that is attached to or can be attached to the syringe gasket, wherein the plunger has a plunger-side threaded portion having one or more plunger-side threads formed on the outer surface of its tip, and the gasket-side threaded portion of the syringe gasket and the plunger-side threaded portion of the plunger are screwable together.

[0008] (9) In the syringe gasket plunger described in (8) above, it is preferable that the plunger-side base-side inclination angle, which is the inclination angle of the base-side surface of the plunger-side thread of the plunger-side thread of the plunger-side thread with respect to the axis of the plunger, is greater than the tip-side inclination angle, which is the inclination angle of the tip-side surface of the gasket-side thread of the gasket-side thread with respect to the axis of the cylindrical body.

[0009] Furthermore, the following is a device that achieves the above objective: (10) A syringe barrel assembly comprising a syringe barrel, a syringe gasket slidably housed in a liquid-tight and airtight state within the syringe barrel, and a plunger attached to or attachable to the syringe gasket, wherein the syringe gasket is made of an elastic material and comprises a cylindrical body portion, a closed tip surface located at the tip of the cylindrical body portion, a base end opening located at the base end of the cylindrical body portion, and a plunger mounting portion formed inside, wherein the plunger mounting portion comprises a gasket-side threaded portion having one or more gasket-side threads formed on its inner surface, and the tip-side inclination angle, which is the inclination angle of the tip-side surface of the gasket-side threads of the gasket-side threaded portion with respect to the axis of the cylindrical body portion, is greater than the base-side inclination angle, which is the inclination angle of the base-side surface of the gasket-side threads of the gasket-side threaded portion with respect to the axis of the cylindrical body portion. Furthermore, the plunger is provided with a plunger-side threaded portion having one or more plunger-side threads formed on the outer surface of its tip, and the gasket-side threaded portion of the syringe gasket and the plunger-side threaded portion of the plunger are screwable together, and the plunger-side base-side inclination angle, which is the inclination angle of the base-side surface of the plunger-side threads of the plunger-side threaded portion with respect to the axis of the plunger, is greater than the tip-side inclination angle, which is the inclination angle of the tip-side surface of the gasket-side threads of the gasket-side threaded portion with respect to the axis of the cylindrical body, in a syringe barrel assembly.

[0010] The syringe gasket of the present invention is a cylindrical body with a closed tip and an open base, and is slidably housed in a liquid-tight and airtight state within a syringe barrel. It is made of an elastic material and comprises a cylindrical body, a closed tip surface located at the tip of the cylindrical body, a base opening located at the base of the cylindrical body, and a plunger mounting portion formed inside. The plunger mounting portion has a gasket-side threaded portion with one or more gasket-side threads formed on its inner surface. The tip-side inclination angle, which is the inclination angle of the tip-side surface of the gasket-side threads of the gasket-side threaded portion with respect to the axis of the cylindrical body, is greater than the base-side inclination angle, which is the inclination angle of the base-side surface of the gasket-side threads of the gasket-side threaded portion with respect to the axis of the cylindrical body. This makes the mounting (threading) state with the plunger more stable in the syringe gasket, thereby improving operability.

[0011] Furthermore, the syringe plunger with gasket of the present invention comprises the above-mentioned syringe gasket and a plunger that can be attached to or attached to the syringe gasket, wherein the plunger has a plunger-side threaded portion having one or more plunger-side threads formed on the outer surface of its tip, and the gasket-side threaded portion of the syringe gasket and the plunger-side threaded portion of the plunger can be screwed together. This makes the mounting (screwed) state of the syringe gasket and the plunger more stable and improves operability.

[0012] Furthermore, the syringe barrel assembly of the present invention comprises a syringe barrel, a syringe gasket slidably housed in a liquid-tight and airtight state within the syringe barrel, and a plunger attached to or attachable to the syringe gasket, wherein the syringe gasket is made of an elastic material and comprises a cylindrical body portion, a closed end surface located at the tip of the cylindrical body portion, a base end opening located at the base end of the cylindrical body portion, and a plunger mounting portion formed inside, the plunger mounting portion comprises a gasket-side threaded portion having one or more gasket-side threads formed on its inner surface, and the gasket-side threads of the gasket-side threaded portion relative to the axis of the cylindrical body portion on the tip side surface of the gasket-side threads The tip-side inclination angle, which is the angle of inclination, is greater than the base-side inclination angle, which is the angle of inclination of the base-side surface of the gasket-side threads of the gasket-side threaded portion with respect to the axis of the cylindrical body. Furthermore, the plunger is equipped with a plunger-side threaded portion having one or more plunger-side threads formed on the outer surface of the tip, and the gasket-side threaded portion of the syringe gasket and the plunger-side threaded portion of the plunger can be screwed together. The plunger-side base-side inclination angle, which is the angle of inclination of the base-side surface of the plunger-side threads of the plunger-side threaded portion with respect to the axis of the plunger, is greater than the tip-side inclination angle, which is the angle of inclination of the tip-side surface of the gasket-side threads of the gasket-side threaded portion with respect to the axis of the cylindrical body. This makes the mounting (screwed) state between the syringe gasket and the plunger more stable and improves operability.

[0013] Figure 1 is a front view showing an embodiment of the syringe gasket of the present invention. Figure 2 is a cross-sectional view taken along line A-A in Figure 1. Figure 3 is an enlarged view of section B in Figure 2. Figure 4 is a left side view of Figure 1. Figure 5 is a right side view of Figure 1. Figure 6 is an explanatory diagram of an enlarged front portion of the syringe gasket shown in Figure 1. Figure 7 is an enlarged view of section C in Figure 2. Figure 8 is a front explanatory diagram showing an embodiment of a plunger that can be attached to the syringe gasket shown in Figure 1. Figure 9 is a cross-sectional view taken along line D-D in Figure 8. Figure 10 is an enlarged cross-sectional view taken along line E-E in Figure 8. Figure 11 is an enlarged explanatory diagram of the tip portion of Figure 9. Figure 12 is an enlarged cross-sectional diagram showing an embodiment of the plunger with syringe gasket of the present invention. Figure 13 is a perspective explanatory diagram showing an embodiment of a syringe barrel constituting the syringe barrel assembly of the present invention. Figure 14 is a front explanatory diagram of the syringe barrel shown in Figure 14. Figure 15 is a cross-sectional view taken along line F-F in Figure 14. Figure 16 is a cross-sectional diagram illustrating an embodiment of a syringe equipped with the syringe gasket and syringe barrel assembly of the present invention.

[0014] The syringe gasket of the present invention will be described using the embodiment shown in the drawings. As shown in Figures 1 to 7, the syringe gasket 1 of the present invention is a cylindrical body with a closed tip and an open base, and is slidably housed in a liquid-tight and airtight state within a syringe barrel. The syringe gasket 1 is made of an elastic material and comprises a cylindrical body portion 11, a closed tip surface 12 located at the tip of the cylindrical body portion 11, a base end opening 13 located at the base end of the cylindrical body portion 11, and a plunger mounting portion 14 formed inside. The plunger mounting portion 14 is provided with a gasket-side threaded portion (female threaded portion) 30 having one or more gasket-side threads 31 formed on its inner surface, and the tip-side inclination angle θ1, which is the inclination angle of the tip-side surface of the gasket-side threads 31 of the gasket-side threaded portion 30 with respect to the axis of the cylindrical body portion 11, is greater than the base-side inclination angle θ2, which is the inclination angle of the base-side surface of the gasket-side threads 31 of the gasket-side threaded portion 30 with respect to the axis of the cylindrical body portion 11.

[0015] As shown in Figures 1 and 2, the syringe gasket 1 of this embodiment is a cylindrical body having a closed tip and a base opening. The syringe gasket 1 comprises a cylindrical main body portion 11 extending with substantially the same outer diameter, and a closed tip surface 12 located at the tip of the cylindrical main body portion 11.

[0016] The axial length La of the syringe gasket 1 is selected appropriately depending on the intended use of the syringe barrel (type and amount of drug / medicine, etc.), but is preferably 6 to 15 mm.

[0017] The closed tip surface 12 is provided with a tapered tip portion 15 that narrows in diameter (outer shape (outer diameter)) towards the tip. In this embodiment, the tapered tip portion 15 is formed from the tip of the syringe gasket 1 to the entire closed tip surface 12 and up to the first annular rib 21, which will be described later.

[0018] As shown in Figure 2, the taper angle θ5 of the tip tapered portion 15 is 120 to 170°. The lower limit of the taper angle θ5 of such a tip tapered portion 15 may be 125°, 130°, or even 135°. The upper limit of the taper angle θ5 of such a tip tapered portion 15 may be 165° or 160°. In this embodiment, the taper angle θ5 is defined by the portion of the tip tapered portion 15 excluding the R-shaped convex portion 16, which will be described later. The outer surface of the tip tapered portion 15 may be slightly curved, either bulging outward or concave inward.

[0019] Preferably, the taper angle θ5 of the tapered tip portion 15 of the closed tip surface 12 is greater than the taper angle θ6 (see Figure 15) of the inner surface 52 of the barrel-side tip, which is provided on the tip side of the syringe barrel 50 (described later) and whose inner diameter decreases towards the tip, and the difference between them is 3° or less. As a result, when the syringe gasket 1 is advanced inside the syringe barrel 50, the tapered tip portion 15 of the syringe gasket 1 and the inner surface 52 of the barrel-side tip of the syringe barrel 50 come into contact from the outer circumference inward, thereby reducing the amount of residual drug (medicinal solution) inside the syringe barrel. Furthermore, considering the change in shape of the syringe gasket 1 when it is stored (compressed) inside the syringe barrel 50, it is preferable to set the taper angle θ5 of the tip tapered portion 15 of the syringe gasket 1 such that the taper angle of the tip tapered portion 15 when stored (compressed) is greater than the taper angle θ6 of the inner surface 52 of the barrel-side tip of the syringe barrel 50. In addition, it is preferable that the drug discharge port (communication port with the puncture needle 55) of the syringe barrel 50 is located approximately at the radial center.

[0020] The tip of the tapered tip portion 15 is an R-shaped protrusion 16, and the R diameter (radius of curvature) R3 of the R-shaped protrusion 16 is preferably 1 to 3 mm. This prevents damage to the tip of the tapered tip portion 15 while further reducing the amount of residual drug (medicinal solution) in the syringe barrel.

[0021] The syringe gasket 1 has a plurality of (in this case, three) annular ribs (first annular rib 21, second annular rib 22, third annular rib 23) provided at intervals in the axial direction of the cylindrical body portion 11, and the maximum outer diameter Dmax of at least two of the plurality of annular ribs (in this embodiment, all of the first annular rib 21, second annular rib 22, and third annular rib 23) is the same. As a result, axial misalignment of the syringe gasket 1 when housed in the syringe barrel is reduced, the mounting (screwing) state of the syringe gasket 1 with the plunger is stabilized, and operability is improved.

[0022] Specifically, as shown in Figure 1, the first annular rib 21 is provided so as to protrude outward from the tip side of the syringe gasket 1. Preferably, the outer diameter of the first annular rib 21 defines the maximum outer diameter Dmax of the annular ribs 21, 22, and 23. Furthermore, in this embodiment, the tip surface (tip-side annular surface) of the first annular rib 21 is continuous with the closed tip surface 12 (tip tapered portion 15). In other words, the syringe gasket 1 comprises a plurality of annular ribs 21, 22, and 23 provided at intervals in the axial direction of the cylindrical body portion 11, and one of the annular ribs (in this case, the first annular rib 21) is provided at the base end of the closed tip surface 12. This makes it less likely for the drug (liquid) in the syringe barrel to leak out towards the base end from the first annular rib 21, and reduces residual liquid. The outer diameter of such annular rib (first annular rib 21) is preferably 4 to 20 mm.

[0023] In the syringe gasket 1, the second annular rib 22 is provided to protrude outward by a predetermined length towards the base end of the first annular rib 21, and the third annular rib 23 is provided to protrude outward by a predetermined length towards the base end of the second annular rib 22. In this embodiment, the maximum outer diameter Dmax of the first annular rib 21, the second annular rib 22, and the third annular rib 23 are the same, but it is not necessary for all annular ribs (first annular rib 21, second annular rib 22, and third annular rib 23) to have the same maximum outer diameter; it is sufficient if at least two of the annular ribs (for example, the first annular rib 21 and the second annular rib 22, or the first annular rib 21 and the third annular rib 23) have the same maximum outer diameter.

[0024] The maximum outer diameter of the syringe gasket 1 (i.e., the maximum outer diameter Dmax of the annular ribs 21, 22, and 23) is selected appropriately depending on the intended use of the syringe barrel (type and amount of drug (medication), etc.), but is preferably between 4 and 20 mm.

[0025] The syringe gasket 1 comprises three or more (in this case, three) annular ribs (first annular rib 21, second annular rib 22, third annular rib 23) spaced apart in the axial direction, and the minimum outer diameter (diameter of the valley between the ribs) between two adjacent annular ribs is the same for each. Specifically, in this embodiment, the minimum outer diameter D1min of the portion between the first annular rib 21 and the second annular rib 22 (first valley 24) and the minimum outer diameter D2min of the portion between the second annular rib 22 and the third annular rib 23 (second valley 25) are the same. This improves the moldability of the syringe gasket 1.

[0026] In addition, the minimum outer diameters D1min and D2min between two adjacent annular ribs (first valley 24 and second valley 25) in the syringe gasket 1 are appropriately selected depending on the intended use of the syringe barrel (type and amount of drug (medication) etc.), but are preferably between 3 and 19 mm.

[0027] Furthermore, in the syringe gasket 1, the protruding height h1 of the annular ribs 21, 22, and 23 described above (in this embodiment, half of the difference between the maximum outer diameter Dmax of the annular ribs 21, 22, and 23 and the minimum outer diameters D1min and D2min between two adjacent annular ribs (first valley 24 and second valley 25) is preferably 0.2 to 1 mm.

[0028] Furthermore, as shown in Figure 6, it is preferable that a straight section parallel to the axial direction of the syringe gasket 1 is provided for a predetermined length between two adjacent annular ribs (first valley 24 and second valley 25).

[0029] In this embodiment, the third annular rib 23, which is located at the base end of the annular ribs, is positioned a predetermined distance further forward than the base end opening 13 (the base end of the cylindrical body portion 11). Furthermore, in this embodiment, the minimum outer diameter D3min of the portion of the syringe gasket 1 closer to the base end than the third annular rib 23 is larger than the minimum outer diameters D1min and D2min between the two adjacent annular ribs (first valley portion 24 and second valley portion 25) as described above.

[0030] In the syringe gasket 1 of this embodiment, as shown in Figure 6, it is preferable that the axial spacing between two adjacent annular ribs (the spacing P1 between the top of the first annular rib 21 and the top of the second annular rib 22, and the spacing P2 between the top of the second annular rib 22 and the top of the third annular rib 23) is approximately the same, or that spacing P2 is larger than spacing P1. In other words, it is preferable that the spacing P2 between two adjacent annular ribs closer to the proximal end (here, the second annular rib 22 and the third annular rib 23) is larger than the spacing P1 between two adjacent annular ribs closer to the tip (here, the first annular rib 21 and the second annular rib 22). The axial spacings P1 and P2 between two adjacent annular ribs are appropriately selected depending on the application of the syringe barrel (type and amount of drug (medication), etc.), but it is preferable that they be set in the range of 1 to 8 mm.

[0031] The number of annular ribs in a syringe gasket is not limited to the three mentioned above, but is appropriately selected depending on the intended use of the syringe barrel (type and amount of drug / medicine, etc.). However, syringe gaskets are preferably provided with two to four annular ribs.

[0032] The syringe gasket 1 comprises a base end opening 13 located at the base end of a cylindrical body portion 11, and a plunger mounting portion 14 formed inside. Specifically, as shown in Figure 2, the syringe gasket 1 is provided with a recess 17 extending inward from the base end opening 13, and the plunger mounting portion 14 is formed within this recess 17.

[0033] More specifically, as shown in Figures 2 and 7, the plunger mounting portion 14 includes a gasket-side threaded portion (female threaded portion) 30 having one or more gasket-side threads 31 formed on its inner surface. In this embodiment, the gasket-side threads 31 of the gasket-side threaded portion 30 include a tip-direction spiral surface 32 facing the tip side and a base-direction spiral surface 33 facing the base end side.

[0034] Furthermore, the gasket-side thread 31 has a helical top surface 34 that connects the tip-direction helical surface 32 and the base-direction helical surface 33. In other words, the gasket-side thread 31 in this embodiment is a so-called trapezoidal thread, with a trapezoidal cross-section, as shown in Figure 7.

[0035] Furthermore, it is preferable that an R-shape is formed on both sides of the top of the gasket-side thread 31, that is, at the boundary portion (ridge line portion) between the tip-side surface (spiral surface 32 in the tip direction) and the top surface (spiral top surface 34), and at the boundary portion (ridge line portion) between the base-side surface (spiral surface 33 in the base direction) and the top surface (spiral top surface 34). This improves the moldability of the syringe gasket 1. The R-diameter (radius of curvature) of such an R-shape is preferably 0.1 to 0.3 mm.

[0036] As shown in Figure 7, the syringe gasket 1 has a tip-side inclination angle θ1, which is the inclination angle of the tip-side surface of the gasket-side thread 31 of the gasket-side thread 30 (in other words, at least a part of the tip-direction spiral surface 32) with respect to the axis of the cylindrical body 11, which is larger than the base-side inclination angle θ2, which is the inclination angle of the base-side surface of the gasket-side thread 31 of the gasket-side thread 30 (in other words, at least a part of the base-direction spiral surface 33) with respect to the axis of the cylindrical body 11. This makes the mounting (screwing) state with the plunger more stable in the syringe gasket 1 and improves operability. More specifically, because the base-side inclination angle θ2 is relatively small, deformation of the gasket-side thread 31 when the plunger with the syringe gasket 1 attached is pulled is suppressed, making it easier to maintain a stable mounting (screwing) state. Furthermore, the relatively large tip-side inclination angle θ1 makes it easier for the gasket-side thread 31 and the plunger-side thread 71 of the plunger-side threaded portion 70 (described later) to engage when attaching the plunger to the syringe gasket 1, thereby improving the ease of mounting the syringe gasket 1 and the plunger.

[0037] In this embodiment, along the entire length of the gasket-side thread 31, the tip-side inclination angle θ1, which is the inclination angle of the tip-side helical surface 32 with respect to the axis of the cylindrical body portion 11, is greater than the base-side inclination angle θ2, which is the inclination angle of the base-side helical surface 33 with respect to the axis of the cylindrical body portion 11. As a result, the above-mentioned improvements in operability and ease of installation can be achieved along the entire length of the gasket-side thread 31.

[0038] Furthermore, it is preferable that the tip-side inclination angle θ1 is 60 to 80° and the base-side inclination angle θ2 is 55 to 75°. However, the tip-side inclination angle θ1 may also be 65 to 75°, and the base-side inclination angle θ2 may be 60 to 70°.

[0039] Furthermore, it is preferable that the tip-side inclination angle θ1 is 1 to 10° greater than the base-side inclination angle θ2.

[0040] Preferably, the inner edge of the tip-direction helical surface 32 of the gasket-side thread 31 is a gentler inner edge inclination surface or inner edge curved surface than the tip-side inclination angle θ1, which is the inclination angle of the tip-direction helical surface 32 with respect to the axis of the cylindrical body portion 11. This suppresses damage to the gasket-side thread 31 when the plunger with the syringe gasket 1 attached is pulled (the plunger is moved towards the base end), and makes it easier to maintain a stable mounting (screwed) state. In this embodiment, the inner edge of the tip-direction helical surface 32 of the gasket-side thread 31 is an inner edge curved surface (tip-side R-shaped portion 35, which will be described later).

[0041] As shown in Figure 7, the syringe gasket 1 of this embodiment includes a tip-side R-shaped portion 35 provided between the tip-side surface (tip-direction spiral surface 32) of the gasket-side thread 31 of the gasket-side threaded portion 30 and the inner surface of the cylindrical body portion 11, and a base-side R-shaped portion 36 provided between the base-side surface (base-direction spiral surface 33) of the gasket-side thread 31 of the gasket-side threaded portion 30 and the inner surface of the cylindrical body portion, wherein the R diameter (radius of curvature: R1) of the tip-side R-shaped portion 35 is larger than the R diameter (radius of curvature: R2) of the base-side R-shaped portion 36. This suppresses damage to the gasket-side thread 31 and prevents the spacing between adjacent gasket-side threads 31 in the axial direction of the cylindrical body portion 11 from becoming too wide.

[0042] As shown in Figure 3, the syringe gasket 1 includes a spherical projection 26 that protrudes in the direction toward the base end from the base end surface (here, the base end annular surface formed around the base end opening 13 of the syringe gasket 1) and has a spherical surface smaller than a hemisphere. In other words, the projection height h2 of the spherical projection 26 is smaller than the radius of curvature R4. By making the spherical projection 26 have a spherical surface smaller than a hemisphere in this way, damage to the spherical projection 26 can be prevented, and the release properties during molding of the syringe gasket 1 are also improved. The radius of curvature R4 of the spherical surface of the spherical projection 26 can be, for example, 0.2 to 0.6 mm, in which case the projection height h2 of the spherical projection 26 can be 0.1 to 0.5 mm.

[0043] In this embodiment, as shown in Figure 5, four spherical protrusions 26 are provided, and these four spherical protrusions 26 are arranged at equal intervals (90° intervals) in the circumferential direction. It is preferable to provide three to eight spherical protrusions 26, and it is preferable that the multiple spherical protrusions 26 are arranged at equal intervals in the circumferential direction.

[0044] As the constituent material of the syringe gasket 1, known materials conventionally used for syringe gaskets can be used. For example, rubber and elastomers can be mentioned. As the rubber, for example, natural rubber, isoprene rubber, butyl rubber, chloroprene rubber, nitrile-butadiene rubber, styrene-butadiene rubber, and silicone rubber are preferable, and in particular, vulcanized rubber is preferable. As the elastomer, for example, polyvinyl chloride-based elastomers, polyolefin-based elastomers, styrene-based elastomers, polyester-based elastomers, polyamide-based elastomers, polyurethane-based elastomers, and mixtures thereof are preferable. Incidentally, the syringe gasket 1 is preferably made of crosslinked butyl rubber.

[0045] The syringe gasket 1 may be coated with a low drug adsorption substance or the like on the tip side portion. As such a low drug adsorption substance, known substances conventionally used can be used. For example, polyparylene, polyolefin-based resins, fluorine-based resins, and polyester-based resins can be mentioned. As the polyparylene, either poly(parylene) in which no functional group is substituted on the aromatic ring or one in which a functional group is introduced into the aromatic ring or the methylene group may be used. For example, any of poly(chloroparylene) in which chlorine is substituted on the aromatic ring, polymethylparylene in which a methyl group is substituted on the aromatic ring, polyfluoroparylene in which fluorine is substituted on the methylene group, etc. may be used. As the polyolefin-based resin, polypropylene, ultrahigh molecular weight polyethylene, poly(4-methylpentene-1), cyclic polyolefin, etc. are preferable, and as the fluorine-based resin, ethylene tetrafluoride-perfluoroethoxyethylene copolymer, polytetrafluoroethylene, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, etc. are preferable.

[0046] Also, a lubricant or the like can be coated on the surface of the portion (for example, the annular ribs 21, 22, 23) that contacts (slides) with the inner surface of the syringe barrel of the syringe gasket. As such a lubricant, silicone oil or the like can be mentioned.

[0047] Incidentally, although not described in detail, the syringe gasket 1 may be provided with an appropriate R shape at the boundary portion (ridge line portion) between surfaces in order to improve the formability.

[0048] Next, a plunger with a syringe gasket and a barrel assembly for a syringe, each including the syringe gasket of the present invention, will be described using the embodiments shown in the drawings.

[0049] As shown in FIGS. 1 to 12, the plunger 1a with a syringe gasket of the present invention is a plunger 1a with a syringe gasket including the syringe gasket 1 as described above and a plunger 60 attached to or attachable to the syringe gasket 1. The plunger 60 includes a male screw portion (external thread portion) 70 having one or a plurality of plunger-side threads 71 formed on the outer surface of the tip portion, and the gasket-side screw portion 30 of the syringe gasket 1 and the plunger-side screw portion 70 of the plunger 60 are capable of being screwed together.

[0050] An example of the plunger 60 (the plunger 60 constituting the plunger 1a with a syringe gasket) attached to the syringe gasket 1 of the present embodiment will be described using FIGS. 8 to 11. As shown in FIG. 8, the plunger 60 of the present embodiment includes a main body shaft portion 62 extending in the axial direction, a gasket mounting portion 61 provided at the tip portion, a disc-shaped gasket pressing portion 63 provided between the main body shaft portion 62 and the gasket mounting portion 61, and a disc-shaped operation portion 64 provided at the base end portion of the main body shaft portion 62.

[0051] More specifically, the main body shaft portion 62 of the plunger 60 of the present embodiment is formed in a cross-sectional shape (see FIG. 10), and a plurality (here, four) of plate-shaped reinforcing ribs 65 are provided in the middle of the main body shaft portion 62. The number of the reinforcing ribs 65 is appropriately set according to the axial length, radial dimension, etc. of the plunger 60, but the interval between two adjacent reinforcing ribs 65, 65 in the axial direction is preferably 5 to 15 mm. Thereby, deformation and torsion of the main body shaft portion 62 of the plunger 60 can be suppressed. [[ID=*13]]

[0052] Furthermore, in this embodiment, the base end portion of the main shaft portion 62 is a tapered portion 66 in which the outer diameter decreases toward the base end direction (operating portion 64). This improves the operability when operating the plunger 60. Specifically, it becomes easier to place your fingers on the tip side of the operating portion 64 when pulling the plunger 60. The taper angle of such a tapered portion 66 is preferably 5 to 15°.

[0053] The shape of the main shaft portion 62 is not limited to the example shown (cross-shaped cross-section), and may be a columnar shaft. The columnar shaft may be rod-shaped, cylindrical, polygonal columnar, cylindrical, polygonal tube, etc.

[0054] Furthermore, it is preferable to use a rigid or semi-rigid resin such as high-density polyethylene, polypropylene, polystyrene, or polyethylene terephthalate as the constituent material of the plunger 60.

[0055] As shown in Figure 11, the gasket mounting portion 61 provided at the tip of the plunger 60 includes a plunger-side threaded portion (male threaded portion) 70 having one or more plunger-side threads 71 ​​formed on its outer surface. The plunger 60 is attached to the syringe gasket 1 by screwing the plunger-side threaded portion 70 with the gasket-side threaded portion 30 of the syringe gasket 1 described above. The plunger may not be attached to the syringe gasket at this time, but may be attached to the syringe gasket when in use. This prevents the plunger from being accidentally pressed before use.

[0056] In this embodiment, the plunger-side thread 71 of the plunger-side threaded portion 70 comprises a plunger-side tip-direction helical surface 72 facing the tip side and a plunger-side base-direction helical surface 73 facing the base end side. Furthermore, the plunger-side thread 71 comprises a plunger-side helical top surface 74 connecting the plunger-side tip-direction helical surface 72 and the plunger-side base-direction helical surface 73. In other words, as shown in Figure 11, the plunger-side thread 71 in this embodiment is a so-called trapezoidal thread with a trapezoidal cross-section.

[0057] As shown in Figure 11, the plunger-side base-side inclination angle θ4, which is the inclination angle of the base-side surface of the plunger-side thread 71 of the plunger-side threaded portion 70 (in other words, at least a part of the plunger-side base-direction spiral surface 73) with respect to the axis of the plunger 60, is greater than the tip-side inclination angle θ1, which is the inclination angle of the tip-side surface of the gasket-side thread 31 of the gasket-side threaded portion 30 (in other words, at least a part of the tip-direction spiral surface 32) with respect to the axis of the cylindrical body portion 11. As a result, when the plunger 60 is pulled (moved towards the base end), the initial contact point between the plunger 60 (plunger-side thread 71) and the syringe gasket 1 (gasket-side thread 31) becomes the radially outer portion (near the base end in the protruding direction of the gasket-side thread 31 and near the top of the plunger-side thread 71). This suppresses unintended disengagement (unscrewing) of the plunger 60 from the syringe gasket 1, stabilizes the mounting (screw-in) state between the syringe gasket 1 and the plunger 60, and improves operability.

[0058] In this embodiment, along the entire length of the plunger-side thread 71, the plunger-side base-side inclination angle θ4, which is the inclination angle of the plunger-side base-side helical surface 73 with respect to the axis of the plunger 60, is greater than the tip-side inclination angle θ1, which is the inclination angle of the tip-side helical surface 32 of the syringe gasket 1 with respect to the axis of the cylindrical body portion 11. As a result, the above-mentioned improvement in operability can be achieved along the entire length of the plunger-side thread 71.

[0059] Furthermore, the plunger-side base end inclination angle θ4, as described above, is 90° or less, preferably 65 to 85°, and more preferably 70 to 80°.

[0060] Furthermore, the plunger-side base-side inclination angle θ4 may be equal to, greater than, or less than, the plunger-side tip-side inclination angle θ3, which is the inclination angle of the tip-side surface of the plunger-side thread 71 of the plunger-side threaded portion 70 (in other words, at least a part of the plunger-side tip-direction helical surface 72) with respect to the axis of the plunger 60.

[0061] In this embodiment, the plunger 60 is equipped with a disc-shaped gasket pressing portion 63 provided between the main shaft portion 62 and the gasket mounting portion 61. When the plunger 60 is pushed (moved towards the tip) while attached to the syringe gasket 1, the gasket pressing portion 63 contacts the spherical protrusion 26 of the syringe gasket 1, pressing the syringe gasket 1 toward the tip. Furthermore, when the plunger 60 is pushed (moved towards the tip) in this manner, it is preferable that the plunger-side thread 71 (thruscalar surface 72 toward the tip of the plunger) contacts the gasket-side thread 31 (thruscalar surface 33 toward the base end), but does not substantially press against it. This suppresses axial stretching of the syringe gasket 1 and prevents liquid leakage when the plunger 60 is pressed.

[0062] As shown in Figures 1 to 16, the syringe barrel assembly 10 of the present invention comprises a syringe barrel 50, a syringe gasket 1 slidably housed in a liquid-tight and airtight state within the syringe barrel 50, and a plunger 60 attached to or attachable to the syringe gasket 1. The syringe gasket 1 is made of an elastic material and comprises a cylindrical body portion 11, a closed tip surface 12 located at the tip of the cylindrical body portion 11, a base end opening 13 located at the base end of the cylindrical body portion 11, and a plunger mounting portion 14 formed inside. The plunger mounting portion 14 is provided with a gasket-side threaded portion (female threaded portion) 30 having one or more gasket-side threads formed on its inner surface, and the tip-side inclination angle θ1, which is the inclination angle of the tip-side surface (tip-direction spiral surface 32) of the gasket-side thread 31 of the gasket-side threaded portion 30 with respect to the axis of the cylindrical body portion 11, is greater than the base-side inclination angle θ2, which is the inclination angle of the base-side surface (base-direction spiral surface 33) of the gasket-side thread 31 of the gasket-side threaded portion 30 with respect to the axis of the cylindrical body portion 11. Furthermore, the plunger 60 is equipped with a plunger-side threaded portion (male threaded portion) 70 having one or more plunger-side threads 71 ​​formed on the outer surface of its tip, and the gasket-side threaded portion 30 of the syringe gasket 1 and the plunger-side threaded portion 70 of the plunger 60 can be screwed together, and the plunger-side base-side inclination angle θ4, which is the inclination angle of the base-side surface (spiral surface 73 in the direction of the plunger-side base) of the plunger-side threaded portion 70 with respect to the axis of the plunger 60, is greater than the tip-side inclination angle θ1, which is the inclination angle of the tip-side surface (spiral surface 32 in the direction of the tip) of the gasket-side threaded portion 30 with respect to the axis of the cylindrical body portion 11.

[0063] As shown in Figures 13 to 15, the syringe barrel 50 of this embodiment is a so-called syringe barrel with a puncture needle, comprising a cylindrical barrel body portion 53, a cylindrical puncture needle attachment portion 54 provided at the tip of the barrel body portion 53, and a puncture needle 55 having a puncture needle tip at its end, with its base end inserted into and fixed in the puncture needle attachment portion 54.

[0064] The barrel body 53 of the syringe barrel 50 is a substantially cylindrical portion capable of housing the syringe gasket 1 in a liquid-tight and slidable manner. The barrel body 53 is cylindrical in shape, extending with substantially the same inner and outer diameters, and has an internal lumen (internal space) 51 inside. The barrel body 53 also includes a shoulder portion 56 formed at the tip, which tapers in diameter toward the tip, a base end opening 57 formed at the base end, and a flange 58 that protrudes in a flat plate shape from the outer circumference of the base end.

[0065] The syringe barrel 50 in this embodiment is provided with a barrel-side tip inner surface 52 on the inner surface of the tip side of the lumen 51 (more specifically, the inner surface of the shoulder portion 56), the inner diameter of which decreases toward the tip, and as shown in Figure 15, the taper angle θ6 of the barrel-side tip inner surface 52 is defined.

[0066] The barrel body portion 53 of the syringe barrel 50 is preferably transparent or translucent. Examples of materials for forming the barrel body portion 53 include various resins such as polypropylene, polyethylene, polystyrene, polyamide, polycarbonate, polyvinyl chloride, poly-(4-methylpentene-1), acrylic resin, polyester such as acrylonitrile-butadiene-styrene copolymer and polyethylene terephthalate, cyclic olefin polymers, and cyclic olefin copolymers. Among these, polypropylene and cyclic polyolefins (e.g., cyclic olefin polymers and cyclic olefin copolymers) are preferred because they are easy to mold and have heat resistance.

[0067] The inner diameter db of the barrel body 53 is appropriately selected depending on the intended use of the syringe barrel 50 (type and amount of drug (medicine), etc.), but is preferably 4 to 20 mm. In this embodiment, the inner diameter db of the barrel body 53 is shown as being the same along its entire axial length, but there may be slight differences in the inner diameter depending on the part due to draft angles, etc. In that case, it is sufficient if at least a part of it is within the following range. Also, the axial length Lb of the barrel body 53 (here, as shown in Figure 14, the length from the base end of the barrel body 53 to the base end of the shoulder 56) is appropriately selected depending on the intended use of the syringe barrel 50 (type and amount of drug (medicine), etc.), but is preferably 40 to 120 mm.

[0068] In such a syringe barrel assembly 10, the tip-side inclination angle θ1, which is the inclination angle of the tip-side surface (tip-direction spiral surface 32) of the gasket-side thread 31 of the gasket-side thread 30 of the syringe gasket 1 with respect to the axis of the cylindrical body 11, is greater than the base-side inclination angle θ2, which is the inclination angle of the base-side surface (base-direction spiral surface 33) of the gasket-side thread 31 of the gasket-side thread 30 with respect to the axis of the cylindrical body 11. As a result, the syringe gasket 1 can be made more stable in its mounting (screwed) state with the plunger 60, thereby improving operability.

[0069] Furthermore, the syringe gasket 1 (syringe barrel assembly 10) of this embodiment can be used as a syringe 100 by combining it with the syringe barrel 50 and plunger 60 described above, as shown in Figure 16. In the syringe 100 shown in Figure 16, a seal cap 80 for sealing (protecting) the tip of the puncture needle 55 is attached to the syringe barrel 50.

[0070] Within the syringe 100 (syringe barrel 50), a drug (medicinal solution) can be stored in the space formed between the barrel body 53 and the syringe gasket 1. As shown in Figure 16, the syringe 100 can also be used with the drug (medicinal solution) 81 pre-filled (a so-called pre-filled syringe).

[0071] Even in such a syringe 100, the tip-side inclination angle θ1, which is the inclination angle of the tip-side surface (tip-direction spiral surface 32) of the gasket-side thread 31 of the gasket-side thread 30 of the syringe gasket 1 with respect to the axis of the cylindrical body 11, is greater than the base-side inclination angle θ2, which is the inclination angle of the base-side surface (base-direction spiral surface 33) of the gasket-side thread 31 of the gasket-side thread 30 with respect to the axis of the cylindrical body 11. As a result, the syringe gasket 1 can be made more stable in its mounting (screwed) state with the plunger 60, thereby improving operability.

[0072] 1 Syringe gasket 1a Plunger with syringe gasket 10 Syringe barrel assembly 11 Cylindrical body 12 Closed tip surface 13 Base opening 14 Plunger mounting part 30 Gasket side thread 31 Gasket side thread 32 Spiral surface towards tip 33 Spiral surface towards base 50 Syringe barrel 60 Plunger 61 Gasket mounting part 70 Plunger side thread 71 Plunger side thread 72 Spiral surface towards tip on the plunger side 73 Spiral surface towards base on the plunger side 100 Syringe

Claims

1. A syringe gasket having a tubular body with a closed tip and an open base, which is slidably housed in a liquid-tight and airtight state within a syringe barrel, wherein the syringe gasket is made of an elastic material and comprises a tubular body, a closed tip surface located at the tip of the tubular body, a base opening located at the base end of the tubular body, and a plunger mounting portion formed inside, wherein the plunger mounting portion comprises a gasket-side threaded portion having one or more gasket-side threads formed on its inner surface, and the tip-side inclination angle, which is the inclination angle of the tip-side surface of the gasket-side threads of the gasket-side threaded portion with respect to the axis of the tubular body, is greater than the base-side inclination angle, which is the inclination angle of the base-side surface of the gasket-side threads of the gasket-side threaded portion with respect to the axis of the tubular body.

2. The syringe gasket according to claim 1, wherein the gasket-side thread comprises a tip-direction helical surface facing the tip and a base-direction helical surface facing the base, and over the entire length of the gasket-side thread, the tip-side inclination angle, which is the inclination angle of the tip-direction helical surface with respect to the axis of the cylindrical body, is greater than the base-side inclination angle, which is the inclination angle of the base-direction helical surface with respect to the axis of the cylindrical body.

3. The syringe gasket according to claim 2, wherein the gasket-side threads are provided with a helical top surface connecting the tip-direction helical surface and the base-direction helical surface.

4. The syringe gasket according to claim 2 or 3, wherein the inner edge of the tip-direction helical surface of the gasket-side thread is an inner edge inclined surface or inner edge curved surface that is gentler than the tip-side inclination angle, which is the inclination angle of the tip-direction helical surface with respect to the axis of the cylindrical body.

5. The syringe gasket according to claim 1 or 2, wherein the tip-side inclination angle is 60 to 80° and the base-side inclination angle is 55 to 75°.

6. The syringe gasket according to claim 1 or 2, wherein the tip-side inclination angle is 1 to 10° greater than the base-side inclination angle.

7. The syringe gasket according to claim 1 or 2, comprising: a tip-side R-shaped portion provided between the tip-side surface of the gasket-side thread of the gasket-side screw portion and the inner surface of the cylindrical body portion; and a base-side R-shaped portion provided between the base-side surface of the gasket-side thread of the gasket-side screw portion and the inner surface of the cylindrical body portion, wherein the R-diameter of the tip-side R-shaped portion is larger than the R-diameter of the base-side R-shaped portion.

8. A syringe gasketed plunger comprising a syringe gasket according to claim 1 or 2, and a plunger that is attached to or can be attached to the syringe gasket, wherein the plunger has a plunger-side threaded portion having one or more plunger-side threads formed on the outer surface of its tip, and the gasket-side threaded portion of the syringe gasket and the plunger-side threaded portion of the plunger are screwable together.

9. The plunger with a gasket for a syringe according to claim 8, wherein the plunger-side base-side inclination angle, which is the inclination angle of the base-side surface of the plunger-side thread of the plunger-side thread of the plunger-side thread, with respect to the axis of the plunger, is greater than the tip-side inclination angle, which is the inclination angle of the tip-side surface of the gasket-side thread of the gasket-side thread of the gasket-side thread with respect to the axis of the cylindrical body.

10. A syringe barrel assembly comprising a syringe barrel, a syringe gasket slidably housed in a liquid-tight and airtight manner within the syringe barrel, and a plunger attached to or attachable to the syringe gasket, wherein the syringe gasket is made of an elastic material and comprises a cylindrical body portion, a closed tip surface located at the tip of the cylindrical body portion, a base end opening located at the base end of the cylindrical body portion, and a plunger mounting portion formed inside, wherein the plunger mounting portion comprises a gasket-side threaded portion having one or more gasket-side threads formed on its inner surface, and the tip-side inclination angle, which is the inclination angle of the tip-side surface of the gasket-side threads of the gasket-side threaded portion with respect to the axis of the cylindrical body portion, is greater than the base-side inclination angle, which is the inclination angle of the base-side surface of the gasket-side threads of the gasket-side threaded portion with respect to the axis of the cylindrical body portion. Furthermore, the plunger is provided with a plunger-side threaded portion having one or more plunger-side threads formed on the outer surface of its tip, the gasket-side threaded portion of the syringe gasket and the plunger-side threaded portion of the plunger are screwable together, and the plunger-side base-side inclination angle, which is the inclination angle of the base-side surface of the plunger-side threads of the plunger-side threaded portion with respect to the axis of the plunger, is greater than the tip-side inclination angle, which is the inclination angle of the tip-side surface of the gasket-side threads of the gasket-side threaded portion with respect to the axis of the cylindrical body.

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