Syringe with injection needle

Abstract

To provide a syringe with an injection needle having excellent sealing property when a cap is attached and slidability when the cap is detached.SOLUTION: In a syringe 10 with an injection needle, a cylindrical end portion 22 configured by including a side wall 22B defining a hollow part penetrated by the injection needle 14 is formed in a tip end of a nozzle 20 for tightly fixing an injection needle 14 to a syringe body 12. The cylindrical end portion 22 forms the side wall 22B in a tapered shape such that a diameter of the cylindrical end portion 22 becomes narrow toward a needle tip side of the injection needle 14.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a syringe formed by attaching an injection needle, that is, a syringe with an injection needle. [Background technology]

[0002] As a means of protecting the needle of a syringe when it is not in use, for example, during storage or transportation, a rubber cap (also called a needle shield) can be attached to the tip of the syringe on the side where the needle is attached. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7058466 [Patent Document 2] Patent No. 5075982 Summary of the Invention [Problem to be solved by the invention]

[0004] One possible form of syringe with a needle is one in which the needle, which protrudes beyond the surface of the part closely fixed to the nozzle tip of the syringe that holds the needle, is surrounded by a side wall provided at a predetermined distance from the needle tube of the needle. In this type of syringe with a needle, the side wall surrounding the needle tube is formed integrally with the nozzle and extends parallel to the direction in which the needle extends. The needle, which protrudes beyond the surface of the part closely fixed to the nozzle tip, extends within the space surrounded by the side wall, and after protruding from the space surrounded by the side wall, is exposed and extends outside the syringe all the way to the needle tip.

[0005] In this manner, the portion formed at the nozzle tip, whose main component is the side wall facing the injection needle, will be referred to as the "cylindrical end" in this application based on its shape (those skilled in the art may call it various names such as "crown-shaped tip portion" or "crown-shaped tip portion"). A rubber cap for a syringe with an injection needle having such a cylindrical end is attached to the syringe by fitting the cylindrical end of the syringe into the cap space.

[0006] Such syringes are typically molded using a mirrored mold that corresponds to the shape of the cylindrically-ended syringe. However, as a result, when a conventional cylindrically-ended syringe is stored with a rubber cap attached, the rubber forming the inner wall of the cap may adhere to the outer surface of the cylindrical end. When the cap is removed, the rubber may peel off from the cap while still adhering to the outer surface of the cylindrical end of the syringe. The peeled-off rubber may become a foreign object in the medical field, posing a risk of so-called foreign matter contamination.

[0007] Even if the rubber does not adhere to the outer surface of the cylindrical end, the outer surface of the cylindrical end and the rubber inner wall of the cap are in close contact when the syringe with the needle is stored, which increases the tensile strength when the cap is removed from the syringe. This type of attachment structure makes it difficult for medical professionals to use the syringe and can also be a risk factor.

[0008] In the nozzle cap disclosed in Patent Document 1, in order to achieve both sealing property and sliding property, which are mutually exclusive properties, silicone is applied to the surface without the nozzle cap, thereby achieving a certain degree of both rubber elasticity and sliding property. The needle shield disclosed in Patent Document 2 has micro-reliefs on the inner wall of the shield made of an elastomer material, which allows air flow to easily remove the shield when using the injection device.

[0009] However, problems with transferability of the mold surface to rubber products generally occur due to scorching of the rubber material, uneven application of the release agent, and the effects of viscosity and fluidity. If transferability is not sufficiently good, it may not be possible to achieve the sealing and sliding properties expected at the time of design.

[0010] In view of the above problems, an object of the present invention is to provide a syringe with an injection needle that has excellent sealing properties when the cap is attached and excellent sliding properties when the cap is attached and detached. [Means for solving the problem]

[0011] In order to solve the above-mentioned problems, the present invention provides a syringe with an injection needle, which has a cylindrical end formed at the tip of a nozzle that tightly fixes the injection needle to the syringe body, and which includes a side wall that defines a hollow space through which the injection needle passes, and the cylindrical end has a tapered side wall so that the diameter of the cylindrical end becomes thinner as it approaches the needle tip of the injection needle. [Effects of the Invention]

[0012] The present invention has the unique effect of providing a syringe with an injection needle that has excellent sealing properties when the cap is attached and excellent sliding properties when the cap is attached and detached. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a perspective view showing one embodiment of a syringe with an injection needle according to the present invention. [Figure 2] FIG. 2 is a front view of the embodiment of the syringe with needle shown in FIG. 1. [Figure 3] FIG. 2 is a side view of the embodiment of the syringe with needle shown in FIG. 1. [Figure 4] 2 is a cross-sectional view of the embodiment of the syringe with needle shown in FIG. 1. FIG. [Figure 5] FIG. 2 is an enlarged partial cross-sectional view of the embodiment shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] Next, an embodiment of a syringe with a needle according to the present invention will be described in detail with reference to the accompanying drawings. FIGS. 1 to 4 illustrate the overall configuration of one embodiment of a syringe with a needle according to the present invention from various perspectives. Referring to FIG. 1, a syringe with a needle 10 according to one embodiment of the present invention is composed of a syringe body 12 made of synthetic resin and a metal injection needle 14. The syringe body 12 comprises a long, hollow barrel 16, a flange 18 protruding radially outward from one end of the barrel 16, and a nozzle 20 provided at the other end of the barrel 16 to tightly fix the vicinity of the base end of the injection needle 14. The barrel 16 and flange 18 may have shapes similar to those of known syringes.

[0015] Figures 2 and 3 are drawings of the syringe 10 with an injection needle when viewed from an angle different from that of Figure 1. The cross-sectional view of Figure 4 is a drawing of the syringe 10 with an injection needle cut along the cutting line IV-IV shown in Figure 3 and viewed in the direction of the arrow, as a whole.

[0016] The nozzle 20 provided on the needle-equipped syringe 10 fixes the injection needle 14 so that the base end of the injection needle 14 projects into the hollow portion of the outer cylinder 16. In this embodiment, the injection needle 14 is fixed by the nozzle 20 by tightly surrounding the needle tube of the injection needle 14 from the vicinity of the base end of the needle over a sufficient length.

[0017] A cylindrical end portion 22 is provided at the tip portion of the nozzle 20. The cylindrical end portion 22 is formed integrally with the nozzle 20. With this configuration, the injection needle 14 is fixed to the nozzle 20 at a portion near the base end portion, leaving the base end portion in the hollow portion of the outer cylinder 16, and the portion beyond the portion that penetrates the tip portion of the nozzle 20 first extends through the hollow space surrounded by the cylindrical end portion 22 on the sides, and then through the open space, to reach the needle tip.

[0018] The details of the configuration of the cylindrical end portion 22 of the needle-equipped syringe 10 will be explained with reference to Fig. 3 as well as Fig. 5, which shows an enlarged view of the nozzle 20 including the cylindrical end portion 22. The cross-sectional view of Fig. 5 has the same cutting plane and viewpoint as the cross-sectional view of Fig. 4.

[0019] The cylindrical end portion 22 provided on the needle-equipped syringe 10 according to this embodiment is composed of a cylindrical bottom portion 22A that is integrally connected to the tip portion of the nozzle 20, and a side wall 22B that extends from the peripheral edge of the cylindrical bottom portion 22A toward the tip of the injection needle 14. The cylindrical end portion 22 can be molded integrally with the syringe body 12 including the nozzle 20 using a mold. For this reason, it can be said that the tip portion of the nozzle 20 through which the injection needle 14 passes is also the cylindrical bottom portion 22A of the cylindrical end portion.

[0020] Therefore, the material forming the cylindrical end portion 22 may be any material commonly used for syringes. More specifically, it is preferable to form a syringe including the cylindrical end portion 22 from a material that is optically transparent and has a glass transition point or melting point of 110°C or higher, such as polyolefins such as polypropylene, polymethylpentene, and cyclic polyolefins, polycarbonate, polyethylene terephthalate, polyethylene naphthalate, and amorphous polyarylate. Among these, forming a syringe from cyclic polyolefins is particularly preferable in terms of transparency, steam sterilization ability, and non-adsorption of drugs.

[0021] In this embodiment, the periphery of the cylindrical bottom portion 22A is formed in a circular shape with the injection needle 14 as the central axis, and the side wall 22B extends continuously for a certain length along this circular periphery. Therefore, an annular wall is formed around the needle tube of the injection needle 14, and is arranged at a certain distance in the radial direction of the injection needle 14. In other words, the side wall 22B defines from the side the hollow portion of the cylindrical end portion 22 through which the injection needle 14 passes.

[0022] The surface of the side wall 22B of the cylindrical end portion 22 is composed of an outer wall surface 22c, a top wall surface 22d, and an inner wall surface 22e. The outer wall surface 22c is the surface that fits with and attaches to a rubber cap. The top wall surface 22d is the tip surface of the extending side wall 22B. Looking at the needle tip side of the needle-equipped syringe 10 according to this embodiment, both the outer wall surface 22c and the top wall surface 22d are annular (see FIG. 3). In the illustrated embodiment, the top surface of the cylindrical end portion 22 forms an opening defined by the annular top wall surface 22d. The inner wall surface 22e is located opposite the outer wall surface 22c and faces the needle tube of the injection needle 14.

[0023] As described above, the tip of the nozzle 20 through which the injection needle 14 penetrates can also be regarded as the cylindrical bottom 22A of the cylindrical end 22, and therefore the top surface of the cylindrical bottom 22A can also be said to be the bottom wall surface 22f that, together with the inner wall surface 22e, defines the hollow portion of the cylindrical end 22.

[0024] In this embodiment, the bottom wall surface 22f gradually rises around the central portion, i.e., the portion from which the injection needle 14 protrudes, as it approaches the injection needle 14. This more firmly secures the injection needle 14 to the nozzle 20. This raised portion is shown as a raised surface portion 22g in the accompanying drawings. Designing the raised surface portion 22g to be lower than the corresponding portion of a conventional needle-equipped syringe is preferable from the viewpoint of reducing the risk of breakage when the syringe is released from the mold in the injection molding process.

[0025] When the rubber cap is fitted onto the syringe 10 with the injection needle, the fitting surface with the rubber cap is the outer wall surface 22c of the side wall 22B of the cylindrical end 22. The side wall 22B of the cylindrical end 22 is formed in a tapered shape in which the outer wall surface 22c is inclined inward as it extends toward the tip of the side wall 22B. In other words, the cylindrical end 22 is formed so that the outer wall surface 22c of the side wall 22B surrounding the needle tube of the injection needle 14 protruding from the nozzle 20 at a predetermined distance has a predetermined taper angle θ.

[0026] In this way, the cylindrical end 22 has a tapered sidewall 22B so that the diameter of the cylindrical end 22 narrows toward the needle tip of the injection needle 14. The appropriate taper angle θ of the cylindrical end 22 varies depending on the dimensions of the needle-equipped syringe 10, the dimensions and shape of the sidewall 22B of the cylindrical end 22, the exposed length of the injection needle 14 from the nozzle 20, the material of the cylindrical end 22, and the sealing and sliding properties with the cap. Here, the appropriate taper angle θ refers to an angle range that provides excellent properties in sealing when a rubber cap is attached, sliding properties when the rubber cap is attached and removed, and robustness during manufacturing of the syringe 10 and when the cap is attached and removed. For example, the greater the taper angle, the higher the sliding properties, but an excessively large taper angle also reduces the robustness of the sidewall 22B. Therefore, it is necessary to design and manufacture a syringe with a needle that achieves as good a balance between sliding properties and robustness as possible. The syringe with an injection needle 10 having a cylindrical end portion 22 with a taper angle θ is obtained by injection molding the syringe using a mold in which the outer wall surface 22c of the cylindrical end portion 22 is formed with a draft angle corresponding to the taper angle θ.

[0027] If the dimensions and materials of the syringe with a needle are typical, a taper angle θ of more than 0 degrees (0°) and not more than 60 degrees (60°) will result in a syringe with a needle 10 that is excellent in all of sealing properties, sliding properties, and robustness. A preferred taper angle θ is more than 0 degrees and not more than 20°, and an especially preferred taper angle θ is more than 0 degrees and not more than 10°.

[0028] The inner wall surface 22e of the side wall 22B of the cylindrical end portion 22 may extend parallel to the extension direction of the injection needle 14, or may extend away from the extension direction of the injection needle 14 toward the tip of the side wall 22B, i.e., approach the extension direction of the outer wall surface 22c. When the side wall 22B is formed in the latter manner, the relative degree of expansion between the line extending along the outer wall surface 22c of the side wall 22B and the line extending along the inner wall surface 22e, i.e., the taper angle, becomes larger than in the former case. This makes it easier for the side wall 22B to be released from the mold when the syringe is injection molded using the mold.

[0029] Of the side wall 22B of the cylindrical end 22, at least the outer wall surface 22c is roughened. The roughened outer wall surface 22c is obtained by injection molding the syringe using a mold in which the portion corresponding to the outer wall surface 22c is roughened. This prevents the cylindrical end 22 and the rubber of the cap from adhering over time, even when the syringe 10 with the needle attached is stored with the rubber cap fitted and attached. Furthermore, by roughening the outer wall surface 22c, it is possible to reduce the strength required to pull out the rubber cap from the syringe 10 with the needle attached.

[0030] The appropriate surface roughness of the outer wall surface 22c varies depending on the dimensions and shape of the injection needle syringe 10, the material from which the syringe is made, and other factors. Considering the relationship between the taper angle θ of the cylindrical end 22 and the surface roughness of the outer wall surface 22c, increasing the taper angle of the outer wall surface 22c of the cylindrical end 22 allows for a greater surface roughness. This improves mold releasability and prevents rubber adhesion during storage. However, because the rubber cap must be held in place by the side wall 22B of the cylindrical end 22 when the cap is attached, the taper angle and surface roughness must be set to ensure a certain level of retention. Furthermore, to minimize the risk of defective syringes manufactured using a mold, it is preferable to set the surface roughness of the outer wall surface 22c taking into account undercut issues.

[0031] Styrene-ethylene-butylene-styrene block copolymer (SEBS) is particularly suitable as the main elastic material for rubber caps. Other suitable elastic materials for rubber caps include thermoplastic elastomers with excellent heat resistance and elution characteristics, such as styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), and styrene-isobutylene-styrene block copolymer (SIBS). Furthermore, synthetic rubbers, such as butyl rubber (IIR), chlorinated butyl rubber (CIIR), brominated butyl rubber (BIIR), and ethylene-propylene-diene terpolymer rubber (EPDM), are also suitable elastic materials for rubber caps, considering their gas barrier properties and elution characteristics. Therefore, when designing and manufacturing an embodiment of the syringe with a needle 10 according to the present invention, it is preferable to determine the taper angle θ and the surface roughness of the syringe with a needle 10 so that a cap made of such a material provides good sealing, sliding, and robustness when fitted and attached. [Example]

[0032] A syringe 10 with an injection needle according to one embodiment of the present invention was manufactured by injection molding using a mold. The manufactured syringe 10 with an injection needle was formed so that the taper angle θ between the straight lines extending from the outer wall surface 22c of the cylindrical end 22, which forms the fitting surface with the rubber cap, was 6 degrees (6°), and the outer wall surface 22c was roughened. Other than these, the basic shape, structure, and dimensions were the same as those of a general syringe with an injection needle.

[0033] Three measurement points 1, 2, and 3 were randomly selected from the outer wall surface 22c of the cylindrical end portion 22 of the manufactured syringe with a needle 10, and the arithmetic mean roughness (Ra) and ten-point mean roughness (Rz) of each measurement point were measured in accordance with JIS B 0601-1994. The measurement results and the average values ​​of the surface roughness of each measurement point are shown in Table 1 below.

[0034] [Table 1]

[0035] For comparison, three measurement points 1, 2, and 3 were randomly selected from the surface of the outer barrel 16 of the same syringe with a needle 10 as that used to measure the outer wall surface 22c of the cylindrical end portion 22, and the arithmetic mean roughness (Ra) and ten-point mean roughness (Rz) of each measurement point were measured in accordance with JIS B 0601-1994. The measurement results and the average values ​​of the surface roughness of each measurement point are shown in Table 2 below.

[0036] [Table 2]

[0037] The difference between the outer wall surface 22c of the syringe with a needle 10 that was the subject of measurement and the surface of the outer cylinder 16 is whether the surface is roughened or not. The mold used to injection mold the syringe body 12 of the syringe with a needle 10 had a roughened mold surface in the part corresponding to the outer wall surface 22c, while the mold surface in the part corresponding to the outer cylinder 16 was a mirror finish.

[0038] When a cap made of a rubber material, hydrogenated styrene thermoplastic elastomer (SEBS), was fitted onto the syringe 10 with the needle for which the above-mentioned measurements were obtained, good sealing properties were obtained. Furthermore, when the syringe 10 with the SEBS cap fitted thereto was stored for a considerable period of time and then the cap was removed, good sliding properties were obtained, but no pieces of rubber material adhered to the outer wall surface 22c and peeled off from the cap were found. From this, it was found that if the arithmetic mean roughness (Ra) of the outer wall surface 22c of the cylindrical end portion 22 is about 0.55 or more, or the ten-point mean roughness (Rz) is about 4.0 or more, sufficient effects can be obtained to prevent rubber adhesion during storage and to reduce the pull-out strength of the rubber cap.

[0039] Although the configuration of one embodiment of the present invention and examples of its products have been described above, the present invention is not limited to the above-described embodiment and product examples described with reference to the drawings. It is obvious to those skilled in the art that the present invention can be variously modified and substituted, or that the essential configuration of the above-described embodiment can be equivalently configured, without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0040] 10 syringes with needles 12 Syringe body 14 Syringe needle 16 Outer cylinder 18 flange 20 nozzles 22 Cylindrical end 22A cylinder bottom 22B side wall 22c External wall surface 22d Top wall surface 22e Inner wall 22nd floor bottom wall 22g surface ridge

Claims

1. A syringe with an injection needle, in which a nozzle that tightly fixes the injection needle to a syringe body has a cylindrical end formed at a tip thereof, the cylindrical end including a side wall that defines a hollow portion through which the injection needle passes, A syringe with an injection needle, characterized in that the cylindrical end has a tapered side wall so that the diameter of the cylindrical end becomes smaller toward the needle tip of the injection needle.

2. 2. The syringe with an injection needle according to claim 1, wherein the outer surface of the side wall is rough.

3. 3. The syringe with an injection needle according to claim 2, wherein the arithmetic mean roughness (Ra) of the outer wall surface is 0.55 or more.

4. 3. The syringe with an injection needle according to claim 2, wherein the ten-point mean roughness (Rz) of the outer wall surface is 4.0 or more.

5. 5. The syringe with an injection needle according to claim 1, wherein the tapered angle of the cylindrical end portion is greater than 0° and is not greater than 60°.

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