CN109641108A

CN109641108A - Syringe plunger, its manufacturing method and medical syringe

Info

Publication number: CN109641108A
Application number: CN201780050224.5A
Authority: CN
Inventors: 铃木启介; 大浦知之
Original assignee: Naigai Kasei Co Ltd
Current assignee: Naigai Kasei Co Ltd
Priority date: 2016-09-05
Filing date: 2017-08-25
Publication date: 2019-04-16
Anticipated expiration: 2037-08-25
Also published as: CN109641108B; JP6889921B2; JP2018038813A; WO2018043356A1

Abstract

The degree that the present invention provides the welding at a kind of gasket and the contact surface of piston body is uniform, and syringe plunger, its manufacturing method and the medical syringe of the disengaging that both can be prevented, the positional shift of gasket when piston body to be installed on to gasket and the generation because of the shape distortion caused by deformation.Syringe plunger (21) of the invention has: piston body portion (20)；Interconnecting piece (24) set on the front end of piston body portion (20)；Front end closing and open rearward end, and at least part of gasket (23) of interconnecting piece (24) is stored from rear end side, recess portion (27) are equipped in the central part of interconnecting piece (24) front-end surface, recess portion (27) is the molten resin receiving unit for receiving the molten resin for sealing mat forming supplied when gasket (23) shape, and the inner wall of gasket (23) is welded together at the contact surface including including at least recess portion (27) with interconnecting piece (24).

Description

Syringe plunger, its manufacturing method and medical syringe

Technical field

The present invention relates to syringe plunger, its manufacturing method and medical syringes, more specifically, relate to prevent The only positional shift of gasket, the syringe plunger of the generation of shape distortion, its manufacturing method and medical syringe.

Background technique

In recent years, the precharging injection syringe for being pre-filled with medical fluid is widely used.Gasket in precharging injection syringe Insertion is formed as in the outer cylinder for sealing front opening in the method using the method for being referred to as so-called vacuum capping State filled with medical fluid, gasket, is configured at the opening portion of outer cylinder, then, shape by atmosphere (atmosphere under vacuum) under reduced pressure As normal pressure state, thus gasket is inserted into outer cylinder.In addition, in precharging injection syringe, sometimes in the envelope of gasket After lid operation, plunger is installed and is assemblied in the gasket, in this fashion, in order to be easy to carry out plunger to gasket Installation, and leakage when installation is prevented, inhibit the rising of internal pressure, external thread part usually is set in plunger, in gasket Internal thread part is set, and the two is connected into (for example, referring to following patent documents 1) by screwing togather.

However, if the construction for connecting plunger and gasket by screwing togather, then there are the relaxation in assembling or use, The case where being detached to plunger.In addition, needing when rotating plunger when plunger and gasket to be attached to syringe It is screwed into plunger with outer cylinder, if not being pressed into rotatably, is difficult to screw togather with gasket.As a result, in the presence of in advance covering Gasket is pressed by plunger, thus the case where generating the shape distortions such as positional shift or the deformation of the gasket.As a result, there are Lead to the problem of the leakage for the medical fluid filled in syringe outer cylinder or being mixed into for bubble.

In addition, a kind of plunger of medical syringe is disclosed in following patent documents 2, corresponding with gasket The inside of piston main body is equipped with the component for being equivalent to the piston body of internal thread part, by making the component and being equivalent to external thread part The second component of piston body screw togather, to be connected.According to the patent document, be formed as piston main body and piston body portion The construction that is mutually welded together at contact surface of component.

However, in patent document 2, it is molten at the contact surface between piston main body and the component in piston body portion for making The uniform situation of the degree connect is not made to consider.Thus, for example, carrying out going out using autoclave etc. before and after the filling of medical fluid When bacterium is handled, there are at the contact surface being welded together, the problem of component of piston main body and piston body is detached from.Separately Outside, if the degree of welding is uneven, there is also the flatness for the front-end surface for therefore leading to piston main body to be damaged, to produce Raw concave-convex problem.If piston main body front-end surface generate it is concave-convex, be difficult to the medical fluid that will be filled in syringe without The discharge of residual ground.

Moreover, the medical syringe is set to higher than patient in the state of being filled with medical fluid in medical syringe Position in the case where, due to the pressure difference generated by difference of height, can generate medical fluid will rapidly flow to the so-called rainbow of patient Suction phenomenon.Therefore, under normal circumstances, piston body is fixed on syringe pump device etc., to prevent the generation of siphonage, but As it was noted above, if the degree of the welding at contact surface between piston main body and the component in piston body portion is uneven, Even if non-movable piston main body, piston main body can be also detached from from the component of piston body, as a result existed and generated siphonage, lead to medicine Liquid rapidly flows to the problem of patient.In addition, in order to confirm the case where properly having carried out puncture to patient and when carrying out blood back, The problem of being detached from there is also piston main body from the component of piston body.

Existing technical literature

Patent document

Patent document 1: Japanese Unexamined Patent Publication 2003-159330 bulletin

Patent document 2: Japanese Unexamined Patent Application Publication 2006-502896 bulletin

Summary of the invention

Problem to be solved by the invention

The present invention is to complete in view of the issue, it is intended that providing between gasket and piston body The degree of welding at contact surface is uniform, and the disengaging, close when piston body to be installed on to gasket that both can be prevented The positional shift of packing and the syringe plunger of generation because of the shape distortion caused by deformation, its manufacturing method and medical Syringe.

The means used to solve the problem

The present application persons etc. are in order to solve the existing problem, to syringe plunger, its manufacturing method and doctor Treatment is studied with syringe.As a result, discovery can reach the purpose by using following structures, so that complete The present invention.

That is, in order to solve described problem, syringe according to the present invention has with plunger: piston body portion；Interconnecting piece, Its front end for being located at the piston body portion；And gasket, front end closing and open rearward end, and from described in rear end side receiving At least part of interconnecting piece, the syringe plunger is characterized in that, in the central part of the front-end surface of the interconnecting piece Equipped with recess portion, the recess portion is the molten resin for receiving the sealing mat forming supplied in the sealing mat forming Molten resin receiving unit, the gasket and the interconnecting piece are including at least at the contact surface including the recess portion welding one It rises.

According to the structure, piston body portion and gasket are connected via interconnecting piece.That is, being set to plunger by interconnecting piece The front end of main part, gasket accommodate at least part of the interconnecting piece from the rear end side of opening, to constitute syringe use Plunger (hereinafter, otherwise referred to as " plunger ").Gasket and interconnecting piece are welded together at contact surface, thus be integrally formed Construction.Be equipped with recess portion in the central part of the front-end surface of interconnecting piece, in this recess also with the inner wall face contact of gasket and melt It is connected together.Melting tree of the recess portion as the molten resin for receiving the sealing mat forming supplied when sealing mat forming Rouge receiving unit and function.Thus, for example, being supplied from the position opposed with recess portion into the die cavity for sealing mat forming In the case where molten resin, molten resin is first flowed into relative to interconnecting piece to recess portion, and diffusion is filled in entire die cavity later.Pass through The flow regime for controlling molten resin in this way, can improve the welding at the contact surface between gasket and interconnecting piece Degree becomes non-uniform situation.

In addition, the plunger of the structure is unlike existing plunger and gasket, it is by screw thread construction etc. that this is close Packing is directly connected to plunger.Due to connecting for gasket via the interconnecting piece and piston body portion being welded together at contact surface The construction connect, therefore the assembling operation for being directly connected to plunger and gasket can be omitted, so as to prevent from carrying out The positional shift of caused gasket or the generation because of the shape distortion caused by deformation when the assembling operation.

In the structure, preferably, in the front-end surface of the interconnecting piece, it is radial centered on the recess portion or It is equipped with multiple groove portions to swirl shape.For example, the recess portion is first flowed into from the molten resin that the position opposed with recess portion supplies, it It is flowed in the groove portion that radial centered on recess portion or swirl shape is arranged afterwards, and diffuses to entire die cavity.In this way, by pair The flow direction of molten resin guides, and can further improve the welding at the contact surface between gasket and interconnecting piece Degree become non-uniform situation.

In addition, in the structure, preferably, the connecting side in the interconnecting piece with the piston body portion is equipped with prominent Out to the flange part of radial outside, the diameter of the flange part is roughly the same with the diameter of the outer peripheral surface of the gasket.Pass through There is the flange part of the diameter roughly the same with the diameter of the outer peripheral surface of gasket in interconnecting piece setting, thus will be of the invention When syringe is contained in the outer cylinder of syringe with plunger and combines, syringe plunger of the invention can be made with will be convex The state that edge is connected to the inner peripheral surface of the syringe is slided.As a result, syringe column of the invention can be prevented The case where plug is slided when shaking, to realize the promotion of the syringe plunger relative to the sliding property of syringe.

In the structure, preferably, the interconnecting piece has an internal thread part in inside, the piston body portion have with The external thread part that the internal thread part screws togather, the interconnecting piece are engaged with the piston body portion by screwing togather construction.This hair It is bright unlike existing plunger and gasket, constructed etc. by screw thread and be directly connected to plunger and the gasket.Pass through spiral shell Conjunction engages piston body portion with interconnecting piece, which makes at least part be contained in the inside of gasket, and passes through welding It is wholely set with gasket.That is, since gasket and interconnecting piece are integrally formed, even if making piston body portion by screwing togather External thread part is connect with the internal thread part of the interconnecting piece, can also prevent the positional shift or deformation, shape of the gasket The case where deformation.As a result, the leakage of medical fluid caused by capable of preventing thus or being mixed into for bubble.

, can be using such as flowering structure in the composition: the interconnecting piece has main part and top, the main part tool Standby cricoid stage portion, the top are set to the front end of the main part, and the internal thread part is set to the ratio step of the main part The forming position in portion is more posteriorly in place of end side, the utilization that the inside of the interconnecting piece passes through the piston body portion and the interconnecting piece The engagement for screwing togather construction is more leaning on top side to become hollow than the stage portion.

In the structure, preferably, the gasket is made of thermoplastic elastomer resin.

In addition, to solve the above-mentioned problems, the manufacturing method of syringe plunger according to the present invention is following injection The manufacturing method of device plunger, the syringe have with plunger: piston body portion；Interconnecting piece is located at the piston body The front end in portion；And gasket, front end closing and open rearward end, and at least the one of the interconnecting piece is accommodated from the rear end side The manufacturing method of part, syringe plunger is characterised by comprising: being formed in using the first mold and sharing die The process that the central part of front-end surface has the interconnecting piece of recess portion, first mold, which has, is used to form the interconnecting piece Front end geometry and side view inner surface configuration, the sharing die has the inner shape for being used to form the interconnecting piece Inner surface configuration；Using the second mold, molded with maintaining state and the sharing die of the interconnecting piece in inside, from Molten resin supplies cast gate and supplies molten resin, and is filled in die cavity, cools down to the molten resin filled, from And it shapes with the interconnecting piece in the work for including at least the gasket being welded together at the contact surface including the recess portion Sequence, second mold are capable of forming the described of the forming of the gasket when combining with the sharing die Die cavity, also, second mold has in the position opposed with the recess portion of the interconnecting piece towards recess portion supply melting tree The molten resin of rouge supplies cast gate.

In the structure, firstly, being attached the forming in portion using the first mold and sharing die.First mold tool It is ready for use on the inner surface configuration of the front end geometry and side view to form interconnecting piece, is especially arranged to inner surface configuration: making to connect The front end geometry of socket part forms recess portion in the central part of front-end surface.In addition, sharing die, which has, is used to form the interior of interconnecting piece The inner surface configuration of side shape.

Then, prepare the second mould that the die cavity of the forming of gasket is capable of forming when together with shared die assembly Tool.Second mold has in the position opposed with the recess portion for being set to interconnecting piece for supplying molten resin towards the recess portion Molten resin supplies cast gate.Then, the second mold and sharing die are molded with the state for maintaining interconnecting piece in inside, And molten resin is supplied into the die cavity being consequently formed from molten resin supply cast gate.Due to molten resin supply cast gate be set to The opposed position of the recess portion of interconnecting piece, therefore the molten resin supplied first flows into recess portion and diffuses to entire die cavity later It is interior.Then, by being cooled down to the molten resin being filled in die cavity, thus formation and interconnecting piece welding at its contact surface The gasket of state together.In this way, in the structure, when supplying molten resin, by being by flow regime control The molten resin first flows into the recess portion of interconnecting piece, so as to improve the journey of the welding at the contact surface between gasket and interconnecting piece Degree becomes non-uniform situation.

In addition, in the manufacturing method, unlike existing plunger and gasket, constructed etc. by screw thread by column Plug is directly connected to the gasket and is manufactured.Since gasket is via the interconnecting piece and column being welded together at contact surface Main part connection is filled in, therefore the group that the manufacturing method of the structure can be omitted for being directly connected to plunger and gasket is pretended Industry.In addition, can not generate when carrying out the assembling operation positional shift of caused gasket and because of deformation caused by shape Under the premise of shape deforms, plunger is manufactured.

In the structure, preferably, in the front-end surface of the interconnecting piece, it is radial centered on the recess portion or Swirl shape it is formed with multiple groove portions.For example, first flow into from the molten resin that the position opposed with recess portion supplies to the recess portion, it It is flowed in the groove portion being arranged radially centered on recess portion afterwards, and diffuses to entire die cavity.In this way, by molten resin Flow direction guide, so as to further improve the journey of the welding at the contact surface between gasket and interconnecting piece Degree becomes non-uniform situation.

In the structure, preferably, as the molten resin, resulting tree is melted using thermoplastic elastomer resin Rouge.

In order to solve described problem, medical syringe of the invention is characterized in that having: previously described syringe Use plunger；And syringe outer cylinder, the syringe is stored in a manner of sliding freely with gasket.

According to the structure, since gasket is wholely set by the interconnecting piece of welding and syringe plunger, energy Enough relaxations or disengaging prevented when in use between the two.In addition, for example, not needing for making syringe plunger and being covered in The assembling operation that the gasket of syringe outer cylinder is directly connected to.Therefore, operability improves, and can prevent because carrying out the assembling The leakage of medical fluid caused by the positional shift or deformation of the gasket generated when operation, the mixed generation of bubble.

Invention effect

According to the present invention, be formed as gasket to be wholely set at its interconnecting piece by welding and plunger, and connecting The central part of the front-end surface in portion is equipped with the structure of recess portion.It is supplied for receiving when sealing mat forming moreover, recess portion is used as Sealing mat forming molten resin molten resin receiving unit and function, be able to suppress in the present invention as a result, molten The case where flowing of melt resin becomes turbulent condition, and can improve molten at the contact surface between gasket and interconnecting piece The degree connect becomes non-uniform situation.

As a result, for example, before and after the filling of medical fluid etc. progress the medical syringe using autoclave etc. Sterilizing when, be able to suppress at the face of weld between gasket and interconnecting piece generate disengaging the case where.In addition, by making welding Degree it is uniform, so that the flatness of the front-end surface of gasket is not damaged, thus can make the front-end surface of gasket with The shape of the inner wall for the syringe outer cylinder stored in a manner of sliding freely to gasket is accurately bonded.It is tied Fruit is, in medical syringe of the invention, can make to be filled in syringe and is discharged residue-free with the medical fluid in outer cylinder.Separately Outside, even if the medical syringe to be set to the position higher than patient to be filled with the state of medical fluid in medical syringe It sets, can also prevent the generation of the disengaging at the face of weld between gasket and interconnecting piece.As a result, medical fluid can be prevented anxious The generation of the so-called siphonage of patient is flowed to fastly.In addition, being appropriately the feelings of puncture to patient to confirm Condition and when carrying out blood back, the case where capable of also preventing gasket to be detached from from interconnecting piece.

Moreover, according to the present invention, since gasket-like becomes interconnecting piece of the receiving for connecting with piston body portion extremely Few a part, and the construction being welded together at the contact surface contacted with interconnecting piece, therefore can prevent when using etc., The case where generating relaxation between gasket and piston body portion or being detached from.Moreover, when in use, without as existing plunger that The assembling operation that plunger and gasket are directly connected to by sample, therefore operability is promoted, and can be prevented due to when carrying out the operation The leakage of medical fluid caused by the positional shift or shape distortion of generated gasket, the mixed generation of bubble.

Detailed description of the invention

Fig. 1 is the cross-sectional view for indicating medical precharging injection syringe involved in embodiments of the present invention 1.

Fig. 2 is to indicate the syringe plunger of the medical precharging injection syringe and the side view of syringe outer cylinder.

Fig. 3 is the cross-sectional view for indicating the outline of the syringe plunger.

Fig. 4 is that the section view of the gasket for indicating the syringe plunger and the outline for the interconnecting piece being contained in the gasket is shown It is intended to, (b) of the figure is the top view for indicating the flat shape of interconnecting piece, and (c) of the figure is to indicate putting down for other interconnecting pieces The top view of face shape.

(a) of Fig. 5 is the side view for indicating the gasket of the syringe plunger, and (b) of the figure is to indicate the gasket Cross-sectional view, (c) of the figure are the top view for indicating the gasket.

Fig. 6 is the schematic cross-sectional view for indicating the forming process of interconnecting piece of the syringe plunger.

Fig. 7 is the schematic cross-sectional view for indicating the forming process of gasket of the syringe plunger.

Fig. 8 is the schematic cross-sectional view for indicating the outline of other interconnecting pieces of the syringe plunger, and (a) of the figure is indicated The position corresponding with recess portion of the inner wall of interconnecting piece is equipped with the case where protrusion, and (b) of the figure indicates that interconnecting piece does not have flange The case where portion.

Fig. 9 is the section view for indicating the syringe plunger of medical precharging injection syringe involved in embodiments of the present invention 2 Figure.

(a) of Figure 10 is to indicate the gasket of the syringe plunger and the side view of interconnecting piece, and (b) of the figure is to indicate to be somebody's turn to do The cross-sectional view of gasket and interconnecting piece, (c) of the figure are the cross-sectional view for indicating the interconnecting piece.

Specific embodiment

(embodiment 1)

[medical syringe]

As the medical syringe (hereinafter referred to as " syringe ") of present embodiment, below by taking precharging injection syringe as an example into Row explanation.Fig. 1 is the cross-sectional view for indicating the syringe.Fig. 2 is to indicate the syringe plunger of the syringe (hereinafter, claiming For " plunger ") and syringe outer cylinder (hereinafter referred to as " outer cylinder ") side view.

As shown in Figures 1 and 2, the syringe 10 of present embodiment has: having the outer cylinder 11 of spray nozzle part 12 in front end；It is close Seal the cap 3 of spray nozzle part 12；Has the plunger 21 of gasket 23 in interconnecting piece；And it is filled in by outer cylinder 11, cap 3 and gasket 23 The indoor medical fluid 6 formed.

Outer cylinder 11 has: being generally constructed to the cylindrical portion 13 of tubular；Spray nozzle part 12 set on the front end of the cylindrical portion 13；With And the finger grip 14 set on the rear end of the cylindrical portion 13.The length of outer cylinder 11 is not particularly limited, can be appropriate as needed Ground setting.

Outer cylinder 11 is preferably, can the transparency of degree at least inside visual confirmation or the material of translucence by showing It constitutes, more preferably, is also made of the material of oxygen permeability or water vapor permeability difference.As this material, it is not particularly limited, For example, polyvinyl chloride, polyethylene, polypropylene, polystyrene, polymethylpentene, polycarbonate, polyamide, acrylic acid can be enumerated The polyester such as resin, polyethylene terephthalate, cyclic olefin resins etc..Among these constituent materials, from the easiness of forming, From the perspective of shape stability, manufacturing cost, the preferably resin of polypropylene, polyester, poly- (4- methylpentene -1) etc.

Cylindrical portion 13 is made of the component of bottomed tube.The diameter and length of cylindrical portion 13 are not particularly limited, and can be fitted Locality setting.Central portion in the bottom of cylindrical portion 13 15 is integrally formed with the barrel necking down relative to cylindrical portion 13 Spray nozzle part 12.Spray nozzle part 12 for example install the needle stand of needle tubing (not shown), connector class and use.

Spray nozzle part 12 in the cross-sectional direction (that is, direction vertical with the length direction of cylindrical portion 13) of cylindrical portion 13, Positioned at the center (central mouth) of cylindrical portion 13.But it's not limited to that for present embodiment, for example, it is also possible to be set to from center Deviate the position of (side port).The diameter and height of the opening portion of spray nozzle part 12 are not particularly limited, and can suitably be set.Separately Outside, around spray nozzle part 12, annular wall 17 is equipped in a manner of separating fixed range.The height of the annular wall 17 is set as comparing The height of spray nozzle part 12 is low, and spray nozzle part 12 is set as prominent from the open front of annular wall 17.But it is not limited to this embodiment party Formula, or do not set the mode of annular wall 17.In order to airtightly seal the inner cavity of spray nozzle part 12, the front end of spray nozzle part 12 with Removable mode is equipped with the cap 3 as containment member.In addition, present embodiment it's not limited to that mode, for example, it is also possible to Paste the containment member being made of film etc..

Finger grip 14 is prominent to radial outside relative to cylindrical portion 13, and is integrally formed in outside the cardinal extremity of outer cylinder 11 Week.When making a relative move operation to plunger 21 relative to outer cylinder 11, finger is stuck in finger grip 14 and is operated.Separately Outside, using well known syringe pump, finger grip 14 is fixed on the syringe pump, passes through the pressing of pump, behaviour Make plunger 21 to make a relative move relative to outer cylinder 11.Scale 35 is formed in the outer peripheral surface of cylindrical portion 13.Thereby, it is possible to grasp The liquid measure of medical fluid 6 inside syringe 10.

As shown in figure 3, plunger 21 at least has: piston body portion 20；Interconnecting piece set on the front end in piston body portion 20 24；And the gasket 23 of a part of the interconnecting piece 24 is accommodated from rear end side.

Piston body portion 20 has: section is in the plunger shaft portion 22 of crosswise；Outer spiral shell set on the front of plunger shaft portion 22 Line portion 43；Set on the gasket press section 25 of the rear end of external thread part 43；And the plunger set on the rear end of plunger shaft portion 22 The round plate 26 of pressing, the construction that piston body portion 20 is formed as one by same material forming.Piston body portion 20 with Interconnecting piece 24 is formed as can the internal thread part 24c by the interconnecting piece 24 and the external thread part 43 on gasket press section 25 The construction for screwing togather and connecting.But the present invention is not limited to this mode, piston body portion 20 and interconnecting pieces 24 may be Pass through the integrally formed construction of same material.

Plunger 21 is in addition to gasket 23, by high density polyethylene (HDPE), polypropylene, polystyrene, butadiene-styrene copolymer Object, acrylonitrile-butadiene-styrene copolymer, polymethylpentene, polycarbonate, acrylic resin, poly terephthalic acid second two The hard such as alcohol ester, cyclopolyolefin or semi-rigid resin are constituted.But present embodiment is not limited to the material, can suitably make With other constituent materials.In addition, piston body portion 20 can also be made of from interconnecting piece 24 different materials.

As shown in (a) of Fig. 4 and (b) of Fig. 4, the top 24a of interconnecting piece 24 be it is substantially coniform, main part 24b is circle Column.(a) of Fig. 4 is the schematic cross-sectional view for indicating the outline for the interconnecting piece 24 being contained in gasket 23, and (b) of the figure is table Show the top view of the flat shape of interconnecting piece 24.It is coniform by the way that top 24a to be shaped generally as, it can make in gasket 23 The mobility of the molten resin of the sealing mat forming supplied when forming is promoted.In addition, the shape of interconnecting piece 24 does not limit In the mode, for example, top 24a can be able to be polygon prism shape for substantially multi-prism taper, main part 24b.

As shown in (b) of Fig. 4, a recess portion 27 is equipped in the central part of the front-end surface of interconnecting piece 24 (top 24a).It is recessed Portion 27 is received as the molten resin of the molten resin for receiving the sealing mat forming supplied in form seal pad 23 Portion and function.For example, supplying molten resin into the die cavity for sealing mat forming from the position opposed with recess portion In the case of, molten resin, which is first flowed into relative to interconnecting piece 24 to recess portion 27, to spread later and is filled in entire die cavity.By with Such mode controls the flowing of molten resin, can improve the molten of the contact surface between the inner wall of gasket 23 and interconnecting piece 24 The degree connect becomes non-uniform situation.

The opening shape when vertical view of recess portion 27 is roughly circular (referring to (b) of Fig. 4).Thereby, it is possible to prevent in recess portion After 27 have received the molten resin of sealing mat forming, which is biased to the case where specific direction flows.But recess portion As long as 27 opening shape can be realized the forming of the recess portion 27, it is not particularly limited, for example, it is also possible to be rectangle, more Side shape etc..In addition, the diameter of the opening shape of recess portion 27 is not particularly limited, can suitably set as needed.

The depth shape (cross sectional shape when section view of recess portion 27) of recess portion 27 is coniform.Thereby, it is possible to improve forming Release property of the interconnecting piece 24 afterwards from mold.But as long as the depth shape of recess portion 27 can be realized the forming of the recess portion 27, It is not particularly limited.For example, the wall surface of recess portion 27 may be vertical walls.In addition, the bottom surface of recess portion 27 may be circle Bottom etc..The lower limit value of the depth capacity of recess portion 27 is preferably 0.1mm or more, more preferably 0.2mm or more, especially preferably 0.5mm or more.In addition, the upper limit value of the depth capacity of recess portion 27 is preferably 2mm hereinafter, more preferably 1.5mm is hereinafter, especially excellent It is selected as 1mm or less.By the way that the lower limit value of the depth capacity of recess portion 27 is set as 0.1mm or more, it can be achieved that connecing as molten resin The promotion of the function in receipts portion.On the other hand, by the way that the upper limit value of the depth capacity of recess portion 27 is set as 2mm hereinafter, can prevent The impaired situation of the function as molten resin receiving unit of recess portion 27.That is, the depth in recess portion 27 is more than the upper limit value In the case of, initially flowing into the molten resin in recess portion 27 can be detained, as a result there are the solidification caused by cooling, so that The flowing for the molten resin filled afterwards becomes the case where turbulent condition.Therefore, by the way that the depth of recess portion 27 is set as 2mm hereinafter, The case where molten resin is detained in recess portion 27 can be prevented from initially flowing into, so as to maintain the conduct molten resin of recess portion 27 The function of receiving unit.

In addition, the lower limit value of the maximum gauge for the interconnecting piece 24 being equipped at the part of recess portion 27 is preferably 0.2mm or more, more Preferably 1mm or more.On the other hand, the upper limit value of the maximum gauge of interconnecting piece 24 is preferably 3mm hereinafter, being further preferably 2mm or less.By the way that the lower limit value of the maximum gauge of interconnecting piece 24 is set as 0.2mm or more, it can be ensured that the spatial volume of die cavity, So as to flow supplied molten resin.On the other hand, by the way that the upper limit value of the maximum gauge of interconnecting piece 24 to be set as 3mm is hereinafter, the elongated situation cooling time for being able to suppress molten resin.In addition it is possible to prevent dent (since forming is shunk The deformation of generated depression in the surface) etc. bad orders and shape defect generation.

The rear end side opening of the main part 24b of interconnecting piece 24, and it is equipped with internal thread part 24c inside it.Thereby, it is possible to It is screwed togather with the external thread part 43 being located on gasket press section 25.The plunger 21 of present embodiment is not by screw thread construction etc. It is directly connected to gasket 23.By screw togather make piston body portion 20 at contact surface welding be set to the inside of gasket 23 Interconnecting piece 24 engage.Thereby, it is possible to prevent that plunger and gasket are directly connected in the case where institute constructing by screw thread etc. The positional shift of the gasket of generation or deformation, shape distortion, as a result, the leakage of medical fluid or mixing for bubble can be prevented Enter.

In addition, in the connecting side with piston body portion 20 of interconnecting piece 24, that is, be equipped in the rear end side of main part 24b convex Edge 28.Flange part 28 has the circular shape that radial outside is projected to relative to main part 24b.The diameter of flange part 28 Roughly the same with the diameter of the outer peripheral surface of gasket 23, thus flange part 28 is flushed with the outer peripheral surface of gasket 23.Due to connection Portion 24 has flange part 28, thus when the outer cylinder 11 for being contained in syringe 10 is combined, can make plunger 21 with The state that flange part 28 is connected to the inner peripheral surface of syringe 10 is slided.As a result, can prevent 21 side of plunger from shaking The case where side is slided, thus can realize promotion of the plunger 21 relative to the sliding property of the outer cylinder 11 of syringe 10.

In addition, can be equipped in the front-end surface of interconnecting piece 24 (top 24a) and be connect with recess portion 27 as shown in (c) of Fig. 4 Multiple groove portions 29, and multiple groove portions 29 are radially arranged centered on recess portion 27.The close of recess portion 27 is flowed into as a result, The molten resin of packing formation can be guided by groove portion 29, and radially be flowed from recess portion 27.As a result, can press down The flowing of molten resin processed generates the situation of turbulent flow.The quantity of groove portion 29 is not particularly limited, and can be set as suitably desired It is fixed.In addition, the depth shape (cross sectional shape on the direction at right angle of direction extended with the groove portion 29) about groove portion 29, only It not also to be particularly limited then in the range of the forming that can be realized the groove portion 29.As the depth shape of groove portion 29, Specifically, for example, V-shaped etc. can be enumerated.Moreover, the depth of groove portion 29 is preferably identical as the depth of recess portion 27.As a result, can The case where being enough further reduced the flowing of molten resin becomes turbulent condition.

Each all same length of groove portion 29, extends to peripheral part from recess portion 27 in top 24a.In addition, groove portion 29 Length is not particularly limited, and can suitably be set according to size of top 24a etc..For example, each groove portion 29 can also be at top 24a, which is further extended into, reaches circumferential part.In addition, the length of the extending direction of each groove portion 29 can also be mutually different.The situation Under, for example, groove portion and short groove portion that the length that can be alternately arranged extending direction is long.Thereby, it is possible to make molten resin with recessed Centered on portion 27, radially flowed with uniform amount of flow.

Each groove portion 29 is all with the extension of same depth.In addition, the lower limit value of the depth of groove portion 29 is preferably 0.1mm or more, More preferably 0.2mm or more, especially preferably 0.5mm or more.In addition, the upper limit value of the depth of groove portion 29 be preferably 2mm hereinafter, Further preferably 1.5mm is hereinafter, especially preferably 1mm or less.By by the lower limit value of the depth of groove portion 29 be set as 0.1mm with On, it is able to maintain that the function of the guide portion of the molten resin as flowing.On the other hand, by by the upper limit of the depth of groove portion 29 Value is set as 2mm hereinafter, the situation that the function of guiding to the flowing of molten resin can be prevented impaired.Moreover, each groove portion 29 Depth may be with the mode left and gradually become shallower as from recess portion 27 in the direction of extension.In addition, the depth of each groove portion 29 Degree can also be mutually different.In this case, for example, can be alternately arranged the depth depth of extending direction groove portion and shallow slot Portion.Thereby, it is possible to make molten resin centered on recess portion 27, radially flowed with uniform amount of flow.

The width (and the width in extending direction direction at right angle) of groove portion 29 is identical as the diameter of recess portion 27, as long as It is not particularly limited then less than the diameter.But groove portion 29 is preferably to have that molten resin can be made from the center of top 24a Flow to the width of the degree of peripheral part.In addition, though peripheral part of the width of groove portion 29 from recess portion 27 to top be it is identical, But the present invention is not limited to this.For example, the width of groove portion 29 may be with being left in the direction of extension from recess portion 27 and The mode gradually to broaden or the mode to narrow.

Although moreover, the groove portion 29 of present embodiment top 24a from the recess portion 27 at center to peripheral part radially Extend, but the present invention is not limited to this modes.For example, it is also possible in such a way that 27 center of recess portion extends in swirl shape. In this case, it is able to extend the runner of the molten resin of flowing, thus, it is possible to reduce the position of molten resin delay.

The constituent material of interconnecting piece 24 is not particularly limited, for example, high density polyethylene (HDPE), polypropylene, polyphenyl can be enumerated Ethylene, butadiene-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, polymethylpentene, polycarbonate, propylene The hard such as acid resin, polyethylene terephthalate, cyclopolyolefin or semi-rigid resin etc..In addition, as interconnecting piece 24 Constituent material can enumerate polyvinyl chloride thermoplastic elastomer resin, polyolefin thermoplastic elastomer resin, polystyrene heat Thermoplastic elastic resin, Polyester thermoplastic elastomer resin, Thermoplastic polyamide elastomer resin, polyurethane series thermoplasticity Thermoplastic elastomer resins such as elastomer resin and their mixture etc..In the structure for selecting interconnecting piece 24 among these materials When at material, preferably it is chosen so that the hardness of the interconnecting piece 24 is greater than the material of the hardness of gasket 23.In addition, interconnecting piece 24 constituent material both can be identical as the constituent material of plunger 21, can also be different.Also, considering the hardness of plunger 21 In the case of, when selecting the constituent material of interconnecting piece 24, preferably selection has the material with the same above hardness of plunger 21.

As shown in Figures 1 and 2, gasket 23 is contained in a manner of it can slide in the cylindrical portion 13 of outer cylinder 11.Separately Outside, as shown in (c) of (a) of Fig. 5~Fig. 5, gasket 23 is included with the gasket main part of roughly the same outer diameter extension 31；The closure 33 of the front end of gasket main part 31；And the opening portion 34 of the rear end of gasket main part 31.In addition, close Packing 23 is solid.(a) of Fig. 5 is the side view for indicating the gasket of the syringe plunger, and (b) of Fig. 5 is to indicate The cross-sectional view of the gasket, (c) of Fig. 5 are the top view for indicating the gasket.Gasket 23 be equipped with opening portion 34 be in order to Accommodate at least part of interconnecting piece 24.

Closure 33 becomes the shape being consistent with the shape of the inner wall of the bottom 15, so that in the bottom 15 with outer cylinder 11 Inner wall abut when, do not form gap between the two as far as possible.In addition, interconnecting piece 24 is contained in the opening portion 34 of gasket, it should The inner wall and interconnecting piece 24 of opening portion 34 are in the construction that contact position is seamlessly welded together and is integrally formed.That is, sealing Pad 23 as plunger 21 a part and the construction that is integrally formed.In addition, gasket 23 inner wall with interconnecting piece 24 The corresponding position of recess portion 27 is equipped with protrusion 36.In addition, " welding " refers to following meaning: as described later, by utilizing The heat for the molten resin that injection molded etc. is injected when gasket 23 is formed makes the table of interconnecting piece 24 to connect therewith Face melting, as a result after the gasket 23 forming, gasket 23 is in combined at its contact surface with interconnecting piece 24 State.

Between gasket main part 31 and closure 33, and in the rear end of gasket main part 31, it is respectively equipped with ring Shape rib 32.Cyclic rib 32 contacts in liquid-tight manner with the inner wall of the cylindrical portion 13 of outer cylinder 11.As long as in addition, the quantity energy of cyclic rib 32 The fluid tight and sliding property for enough maintaining gasket 23, then be not particularly limited.

As long as gasket 23 is made of elastic material, it is not particularly limited, conventionally known material can be used.Elasticity Material refers to following meaning:, can be with the cyclic rib 32 and tubular of gasket 23 at least when plunger 21 is accommodated in outer cylinder 11 The material that the degree that the inner wall in portion 13 contacts in liquid-tight manner deforms.More specifically, for example, thermoplastic elastic can be enumerated Body resin, polyolefin-based resins, fluorine resin, polyester based resin.As thermoplastic elastomer resin, for example, it is preferable to be polychlorostyrene Ethylene based thermoplastic elastomer resin, polyolefin thermoplastic elastomer resin, styrene series thermoplastic elastomer resin, polyester Based thermoplastic elastomer resin, Thermoplastic polyamide elastomer resin, polyurethane series thermoplastic elastomer resin and they Mixture.

Among these constituent materials, in the present embodiment, preferably styrene series thermoplastic elastomer resin and polyester Based thermoplastic elastomer resin.About Polyester thermoplastic elastomer resin, although also relying on the constituent material of interconnecting piece 24 Type, but it is excellent with the weldability of the interconnecting piece of plunger 21 24, so as to prevent the disengaging of plunger 21.In addition, Polyester Thermoplastic elastomer resin is also excellent in terms of heat resistance and abrasion resistence, therefore can also prevent in the sterilization treatment of medical fluid Thermal deformation.As a result, generation or bubble being mixed into medical fluid of the leakage caused by the thermal deformation can be prevented.As described Polyester thermoplastic elastomer resin, can be used commercial goods.As such commercial goods, for example, Primalloy can be enumerated (registered trademark, Mitsubishi Chemical Ind's system), Hytrel (registered trademark, Dong Li E.I.Du Pont Company system) etc..

Lubricant can also be coated on the surface of gasket 23.Thereby, it is possible to make the cylindrical portion 13 relative to outer cylinder 11 Inner wall sliding property it is better.It as the lubricant, is not particularly limited, for example, silicone oil etc. can be used.

Gasket press section 25 be it is discoid, can when making a relative move operation to plunger 21 relative to outer cylinder 11 Gasket 23 is pressed via interconnecting piece 24.In addition, since the peripheral part in gasket press section 25 connects with gasket 23, Gasket 23 can be directly pressed in the peripheral part.The thickness of gasket press section 25 is not particularly limited, can be as needed Suitably set.In addition, the diameter of gasket press section 25 only need to for plunger 21 can be made to slide in outer cylinder 11 degree i.e. Can, it is set as smaller than the internal diameter of the cylindrical portion 13 of outer cylinder 11.

The round plate 26 of plunger pressing be it is discoid, thickness is not particularly limited, and can be set as suitably desired It is fixed.In addition, the diameter of round plate 26 is not also particularly limited, can set as suitably desired.Furthermore, it is also possible to replace circle Pan portion 26, using the component of polygon plate.

It as medical fluid 6, is not particularly limited, preferably using conventionally known precharging injection syringe preparation etc..

[manufacturing method of syringe plunger]

Then, it is illustrated based on Fig. 6 and Fig. 7 in the manufacturing method below to the plunger of present embodiment 21.Fig. 6 is to indicate column The schematic cross-sectional view of the forming process of the interconnecting piece 24 of plug 21.Fig. 7 is cuing open for the forming process of the gasket 23 of expression plunger 21 Depending on schematic diagram.

The manufacturing method of the plunger 21 of present embodiment, which is at least included using the first mold and sharing die, shapes connection The process in portion 24；And in a manner of being welded together at contact surface with the interconnecting piece 24, use the second mold and shared mould The process that tool carrys out form seal pad 23.In the present embodiment, the forming of interconnecting piece 24 and gasket 23 uses double-colored forming process Come carry out.

Firstly, in the forming process of interconnecting piece 24, preparing the first mold 51 and sharing die as shown in (a) of Fig. 6 52, the first mold 51 has the inner surface configuration of the front end geometry and side view that are used to form interconnecting piece 24, sharing die 52 The inner surface configuration for having the inner shape for being used to form interconnecting piece 24.First mold 51 is type core (punch-pin), sharing die 52 For die cavity (cavity plate).First mold 51 becomes with sharing die 52 when having carried out molding, formed can be achieved interconnecting piece 24 at The construction of the die cavity of shape.It is equipped with recess portion forming protrusion 53 in the first mold 51, in the front-end table of interconnecting piece 24 formed thereby The central part in face forms recess portion 27.In addition, the first mold 51 has for supplying the tree to the constituent material as interconnecting piece 24 Rouge melt the first molten resin supply cast gate 54 of resulting molten resin.Although in the present embodiment, the first melting Resin supplies the configuration of cast gate 54 in the central portion of the first mold 51, but the present invention is not limited to this.For example, can be so that melting Resin flows to the mode etc. of thin part from the part of the thickness thickness for the interconnecting piece 24 to be shaped, and suitably sets the first melting The setting position of resin supply cast gate 54.

As shown in (b) of Fig. 6, the first mold 51 is molded with sharing die 52, later, as shown in (c) of Fig. 6, It is injected into carrying out melting resulting molten resin 55 to the resin for the constituent material for becoming interconnecting piece 24 in die cavity, to be connected The forming of socket part 24.It as the injection pressure of molten resin, is not particularly limited, can set as suitably desired.It is infused The molten resin penetrated is cooled in the state of molding.Cooling time is not particularly limited, and can set as suitably desired. After die sinking, as shown in (d) of Fig. 6, the central part for being formed in front-end surface is formed with recess portion 27 and is equipped with interior spiral shell in inside The interconnecting piece 24 of line portion 24c.

Then, it is sealed the forming of pad 23 (referring to (d) of (a)~Fig. 7 of Fig. 7).In the forming of gasket 23, make It is carried out with the second mold 56 and sharing die 52.In addition, for being formed in interconnecting piece 24 and being placed in after molding of gasket 23 It is carried out in the state of two molds 56 and the inside of sharing die 52.Second mold 56 is type core (punch-pin).Second mold 56 is together Become with mold 52 when having carried out molding, forms the construction that the die cavity of forming of gasket 23 can be achieved.In addition, the second mold 56 have and melt to the resin for the constituent material for becoming gasket 23 second melting of resulting molten resin for supplying Resin supplies cast gate (molten resin supply cast gate) 57.Second molten resin supply cast gate 57 is set as and is placed in the after molding Two molds 56 are opposed with the recess portion 27 of interconnecting piece 24 of the inside of sharing die 52.

Shown in (b) of Fig. 7, the second mold 56 is molded with sharing die 52, it later, will as shown in (c) of Fig. 7 The resin for the constituent material for becoming gasket 23 is carried out melting resulting molten resin 58 and is injected into die cavity, to be sealed The forming of pad 23.Here, since the second molten resin supply cast gate 57 is set to the position opposed with the recess portion 27 of interconnecting piece 24, because This molten resin 58 supplied first flows into recess portion 27, later, diffuses in entire die cavity.Thereby, it is possible to improve sealing The degree of the welding at contact surface between pad 23 and interconnecting piece 24 becomes non-uniform situation.

It as the injection pressure of molten resin 58, is not particularly limited, can set as suitably desired.In addition, molten The filling speed (from the speed that is injected into end-of-fill of the molten resin 58 into die cavity) of melt resin 58 is not also limited particularly It is fixed, it can suitably be set according to injection pressure etc..It can also carry out after the injection of molten resin 58 in order to compensate for molten resin 58 cooling meat amount and pressure is applied to be compressed the pressure maintaining process of (pressure control) to the molten resin 58.Later, institute The molten resin 58 of injection is cooled in the state of molding.Cooling time is not particularly limited, can be as suitably desired Setting.After die sinking, as shown in (d) of Fig. 7, front end closing is formed, and the sealing of interconnecting piece 24 is accommodated from the opening portion of rear end 34 Pad 23.In addition, the welding at the contact surface including the recess portion 27 comprising interconnecting piece 24 of the inner wall of gasket 23.

In addition, as the method for taking out the gasket 23 after forming and interconnecting piece 24 from sharing die 52, not by particularly It limits, the method that various rotating stripping demouldings can be used.Specifically, for example, motor rack mode, rack pinion mode can be enumerated In the way of (utilize mold opening and closing movement), forced stripper mechanism, sliding type etc. in segmentation.The motor rack mode are as follows: use motor Using the side as the power source to the thread core transmitting rotation for the inner wall forming internal screw thread portion 24c in interconnecting piece 24 Formula.In addition, the rack pinion mode are as follows: the opening and closing campaign that forming machine is transmitted by rack and pinion, so that thread core The mode of rotation.Forced stripper mechanism mode are as follows: force to take out the side of the gasket 23 and interconnecting piece 24 after shaping from sharing die 52 Formula.Sliding type in the segmentation are as follows: the thread core is divided by after forming it is multiple, to be easy to be demoulded Mode.Among these modes, from the thread that can be improved internal thread part 24c, so that with the outer of piston body portion 20 is set to Threaded portion 43 screw togather construction securely from the perspective of, preferably motor rack mode, rack pinion mode (using mold be opened and closed Movement) and the interior sliding type of segmentation.Further, among these modes, from the viewpoint of inhibiting cost of equipment, particularly preferably For motor rack mode.

On the other hand, it about piston body portion 20, can also in addition be made using well known manufacturing process.Specifically, For example, injection molding etc. can be enumerated.Later, by making the external thread part 43 in piston body portion 20 and the internal screw thread of interconnecting piece 24 Portion 24c is screwed togather, and the piston body portion 20 is connected with interconnecting piece 24, and thus, it is possible to produce involved in present embodiment Plunger 21.

[other business]

About gasket and the construction for the interconnecting piece for being contained in gasket, in the present embodiment, for example, can also be used Fig. 8's (a) or shown in (b) of Fig. 8 it constructs.Fig. 8 is the schematic cross-sectional view for indicating the outline of other interconnecting pieces, and (a) of the figure is indicated The case where the position corresponding with recess portion of the inner wall of interconnecting piece is equipped with protrusion, it is convex that (b) of the figure indicates that interconnecting piece does not have The case where edge.

As shown in (a) of Fig. 8, the global shape of interconnecting piece 24 ' is the flat condition at the not no top in front end, interconnecting piece 24 ' It is made of columned main part 24b.Since interconnecting piece 24 ' does not have substantially coniform top, so that gasket 23 is thickness Wall.It is equipped with recess portion 27 in the central part of the front-end surface of interconnecting piece 24 ', in construction shown in Fig. 8, in the interior of interconnecting piece 24 ' The position corresponding with recess portion 27 of wall surface is additionally provided with protrusion 37.Protrusion 37 is corresponding with recess portion 27.Therefore, the flat shape of protrusion 37 It is identical as the opening shape of recess portion 27, roughly circular, rectangle, polygon etc. can be used.In addition, the height of protrusion 37 and recess portion 27 Depth it is roughly the same, the size when vertical view of protrusion is also identical as the opening shape of recess portion 27.By in the interior of interconnecting piece 24 ' Protrusion 37 corresponding with recess portion 27 is arranged in wall surface, can make thickness and other portions of the central part of the front-end surface equipped with recess portion 27 Split-phase is same.As a result, the case where being able to suppress the mechanical strength reduction of the central part of the front-end surface of interconnecting piece 24 '.

In addition, interconnecting piece 24 " becomes the construction for not having flange part 28 compared with interconnecting piece 24 as shown in (b) of Fig. 8, Interconnecting piece 24 " is all contained in the inside of gasket 23.

(embodiment 2)

Based on Fig. 9 and Figure 10, embodiments of the present invention 2 are being illustrated below.In addition, having about with embodiment 1 The component of same function marks same symbol, and the description thereof will be omitted.Fig. 9 is to indicate medical preliminary filling involved in embodiment 2 The cross-sectional view of the syringe plunger of formula syringe.(a) of Figure 10 is gasket and the connection for indicating the syringe plunger The side view in portion, (b) of the figure are the cross-sectional view for indicating the gasket and interconnecting piece, and (c) of the figure is to indicate the interconnecting piece Cross-sectional view.

About present embodiment 2, as shown in FIG. 9 and 10, in gasket 23 and the welding with interconnecting piece 61 one This point is arranged in ground and embodiment 1 is common.In addition, in the internal thread part 24c by being set to interconnecting piece 61 and being set to gasket External thread part 43 on press section 25 screws togather, and plunger 21 becomes with interconnecting piece 61 can connect and isolated construction this point, It is common with embodiment 1.But present embodiment 2 is in the structurally different from embodiment 1 of interconnecting piece 61.

That is, it is substantially coniform that the interconnecting piece 61 of present embodiment, which becomes top 24a, and main part 62 is with cricoid The generally cylindrical construction of stage portion 63.Stage portion 63 main part 62 cross-sectional direction (that is, the length with main part 62 The vertical direction in direction) on be set as cyclic annular.The top 62a that the ratio stage portion 63 of main part 62 is against the top is contained in gasket 23 Portion.In addition, the gasket main part 31 of the diameter of the lower part 62b of the ratio stage portion 63 of main part 62 on the lower and gasket 23 The diameter of outmost surface is roughly the same, to flush with the lateral circle surface of gasket 23.

Being equipped in the inner wall of the lower part 62b of main part 62 can be with the external thread part 43 in the front for being set to plunger shaft portion 22 The internal thread part 24c screwed togather.Therefore, by external thread part 43 and internal thread part 24c screw togather by piston body portion 20 with In the case that interconnecting piece 61 is connected, space 64 is formed in the inside of interconnecting piece 61 and is become hollow.

In addition, in the present embodiment, by forming space 64 in the inside of interconnecting piece 61, gasket can will be contained in The thickness of the top 62a of the main part 62 of 23 inside is formed as thin-walled.As a result, since the compression that can be realized top 62a becomes Shape, therefore can realize the promotion that plunger 21 is contained in workability of the outer cylinder 11 of syringe 10 to be combined when.On here, The thickness of portion 62a is preferably the range of 0.2mm~1.5mm, more preferably the range of 0.3mm~1.5mm.By by top 62a Thickness be set as 0.2mm or more, the cob webbing of top 62a can be prevented, so as to ensure shape stability.Another party Face, although can prevent from compressing by the way that the thickness of top 62a is set as 1.5mm hereinafter, also relying on the material of interconnecting piece 61 The case where becoming difficult.

In addition, interconnecting piece it is (not shown) or: global shape is the flat condition at the not no top in front end, and only by leading The construction that body portion 62 is constituted.In this case, since interconnecting piece does not have substantially coniform top, so that gasket 23 becomes Heavy wall.In addition, being equipped with protrusion in the position corresponding with recess portion 27 of the inner wall of interconnecting piece.Thereby, it is possible to make to be equipped with recess portion 27 Front-end surface central part thickness it is identical as other parts.As a result, be able to suppress the front-end surface of interconnecting piece The case where mechanical strength of central part reduces.

(other business)

Although in the embodiment 1 or 2, in case where piston body portion and interconnecting piece are connected by screwing togather construction It is illustrated, but the present invention is not limited to this modes.For example, it is also possible to pass through chimeric structure with interconnecting piece for piston body portion Make the construction being connected.In this case, protrusion is set in piston body portion for example, can enumerate, being arranged in interconnecting piece can be with this The mode of the chimeric recess portion in protrusion etc..

In addition, though be illustrated in case where precharging injection syringe in the embodiment 1 or 2, but this Invention is not limited to these modes.For example, it is also possible to be applied to blood sampling syringe, air bag syringe, test it is general Logical syringe etc..

Symbol description

10 (medical) syringes

11 (syringe use) outer cylinders

12 spray nozzle parts

13 cylindrical portions

14 finger grips

15 bottoms

17 annular walls

20 piston body portions

21 (syringe use) plungers

22 plunger shaft portions

23 gaskets

24 interconnecting pieces

24 main parts

At the top of 24a

24b main part

24c internal thread part

25 gasket press sections

26 round plates

27 recess portions

28 flange parts

29 groove portions

31 gasket main parts

32 cyclic ribs

33 closures

34 opening portions

36,37 protrusion

43 external thread parts

51 molds

52 sharing dies

Protrusion is used in the forming of 53 recess portions

54 first molten resins supply cast gate

55 molten resins

56 molds

57 second molten resins supply cast gate

58 molten resins

61 interconnecting pieces

62 main parts

The top 62a

The lower part 62b

63 stage portions

64 spaces

Claims

1. a kind of syringe plunger, has:

Piston body portion；

Interconnecting piece is located at the front end in the piston body portion；And

Gasket, front end is closed and open rearward end, and at least part of the interconnecting piece is accommodated from rear end side,

Wherein, it is equipped with recess portion in the central part of the front-end surface of the interconnecting piece,

The recess portion is the melting for receiving the molten resin for sealing mat forming supplied in the sealing mat forming Resin receiving unit,

The gasket is welded together at the contact surface including including at least the recess portion with the interconnecting piece.

2. syringe plunger as described in claim 1, wherein

In the front-end surface of the interconnecting piece, radial centered on the recess portion or swirl shape it is equipped with multiple groove portions.

3. syringe plunger as claimed in claim 1 or 2, wherein

The flange part for projecting to radial outside is equipped in the connecting side of the interconnecting piece connecting with the piston body portion,

The diameter of the flange part is roughly the same with the diameter of the outer peripheral surface of the gasket.

4. syringe plunger as claimed any one in claims 1 to 3, wherein

The interconnecting piece has internal thread part in inside, and the piston body portion has the external screw thread screwed togather with the internal thread part Portion,

The interconnecting piece is engaged with the piston body portion by screwing togather construction.

5. syringe plunger according to any one of claims 1 to 4, wherein

The interconnecting piece has main part and top, and the main part has cricoid stage portion, and the top is set to the main body The front end in portion,

The internal thread part is set to the forming position of the ratio stage portion of the main part more posteriorly in place of end side,

The inside of the interconnecting piece screws togather the engagement of construction by the utilization of the piston body portion and the interconnecting piece, than described Stage portion more leans on top side to become hollow.

6. syringe plunger according to any one of claims 1 to 4, wherein

The gasket is made of thermoplastic elastomer resin.

7. a kind of manufacturing method of syringe plunger, wherein

The syringe has with plunger:

Piston body portion；

Gasket, front end is closed and open rearward end, and at least part of the interconnecting piece is accommodated from the rear end side,

The manufacturing method of the syringe plunger includes:

Be formed in using the first mold and sharing die front-end surface central part have recess portion the interconnecting piece process, First mold has the inner surface configuration of the front end geometry and side view that are used to form the interconnecting piece, the shared mould The inner surface configuration for having the inner shape for being used to form the interconnecting piece；And

Using the second mold, molded with maintaining state and the sharing die of the interconnecting piece in inside, from molten resin Supply cast gate and supply molten resin, and be filled in die cavity, the molten resin filled is cooled down, thus forming with The interconnecting piece is including at least the process of the gasket being welded together at the contact surface including the recess portion, and described the Two molds are capable of forming the die cavity of the forming of the gasket when combining with the sharing die, also, Second mold has in the position opposed with the recess portion of the interconnecting piece towards the described molten of recess portion supply molten resin Melt resin supplies cast gate.

8. the manufacturing method of syringe plunger as claimed in claim 7, wherein

In the front-end surface of the interconnecting piece, radial centered on the recess portion or swirl shape it is formed with multiple groove portions.

9. the manufacturing method of syringe plunger as claimed in claim 7 or 8, wherein

As the molten resin, resulting resin is melted using thermoplastic elastomer resin.

10. a kind of medical syringe, has:

Syringe plunger according to any one of claims 1 to 6；And

Syringe outer cylinder stores the syringe with gasket in a manner of sliding freely.