WO2017175256A1

WO2017175256A1 - Method for manufacturing bleed type sliding contact ring, and gasket and syringe using sliding contact ring

Info

Publication number: WO2017175256A1
Application number: PCT/JP2016/001934
Authority: WO
Inventors: 四ツ辻　晃
Original assignee: 有限会社コーキ・エンジニアリング
Priority date: 2016-04-06
Filing date: 2016-04-06
Publication date: 2017-10-12
Also published as: JPWO2017175256A1

Abstract

Provided is a manufacturing method for manufacturing a sliding contact ring optimal for gasket assembly. Addition reaction type polysiloxane, a curing catalyst, silicone oil, and a filler are kneaded together to form a silicone rubber G before curing. The silicone rubber G before curing is put inside an accommodation space 41 of a mold K. The silicone rubber G is pressed by a plunger 42 into a cavity 43 from a gate 44. The cavity is filled while the blended silicone oil is caused to bleed onto the surface of the fluid comprising the silicone rubber G that enters the cavity in the process of being pressed. The silicone rubber G that has been pressed inside the cavity 43 is cured to form a sliding contact ring 19 with the silicone oil bled onto the surface thereof. After the curing, the sliding contact ring 19 is removed from the mold K.

Description

Method of manufacturing bleed-type sliding ring and gasket and syringe using the sliding ring

The present invention relates to a method of manufacturing a sliding contact ring used by being fitted into a gasket of a syringe, and more specifically, a sliding contact ring formed by addition reaction type silicone rubber and bleeding a suitable amount of silicone oil as a thin film on the surface during molding. Pertaining to the manufacturing method of The present invention further relates to a gasket using the sliding ring and a syringe using the gasket.

Before use, the syringe is made of a plastic or glass syringe barrel (cylindrical cylinder), a movable piston rod (pusher), a gasket attached to the tip of the piston rod and pressed into the syringe barrel, and The prefilled syringe is made up of a top cap attached to the needle attachment portion, and the syringe barrel is prefilled with a drug solution in the prefilled syringe, and both are used for large consumption.
Each part of such a syringe is mass-produced in a sterile environment under strict standards and assembled into the syringe automatically and as quickly as possible in a short process to prevent contamination of impurities.

The syringe itself has a tight seal (water tightness) that the drug solution filled does not leak from the gasket side, and a contradictory requirement is that the piston rod fitted with the gasket at the time of injection has an initial movement of, for example, 8N (newton) or less It is also required to move smoothly with low sliding resistance, to inhibit the efficacy of the drug solution from the syringe, and to prevent elution of components that impair the health of the person who received the injection into the drug solution.
At the same time, syringes and parts thereof are required to be industrial products having a structure suitable for automation while satisfying the above characteristics. In addition, at the manufacturing site, a working environment in which the health of workers is taken into consideration is required.

Among the parts of the syringe, the one which is structurally complex and which is most relevant to the performance of the syringe is the gasket. There are various conventional gaskets for syringes, and the most popular one is a gasket made of butyl rubber or a gasket made of butyl rubber laminated with a fluorine-based film having excellent slidability.
The butyl rubber gasket has a large sliding resistance against the syringe barrel, so silicone oil is applied to the surface of the butyl rubber gasket or the inner surface of the syringe barrel to ensure low sliding resistance and smooth movement of the piston rod. (Patent Document 1). In addition, it is also pointed out that various additives are mixed in the butyl rubber itself which has been widely used in the past, and these additives are eluted when in contact with the chemical solution.
On the other hand, a gasket in which a fluorine-based film is laminated on the surface of the gasket (Patent Document 2) improves the slidability to some extent by the fluorine-based film, but the chemical solution is a gasket from the gasket and the inner surface of the syringe barrel. There was a problem of water tightness that it leaked to the back side. In addition, this fluorine-based film laminate has another purpose to prevent the additive from eluting out of butyl rubber into a chemical solution.

In addition to these, the above-mentioned silicone oil applied conventionally is aspirated from the injection needle of the approved medical material, or, when it comes in contact with the drug solution already filled in the syringe barrel, the active ingredient in the drug solution It has been pointed out that in some cases, it is pointed out that a syringe may be required which does not use silicone oil (silicone grease).
In addition, at the application site of silicone oil, silicone oil with low molecular weight (low viscosity) was sprayed and applied at high temperature for uniform application to the inner surface of the syringe barrel, and silicone oil did not adhere to the inner surface of the syringe barrel It has also been pointed out that the fog of the house is scattered around and contaminates the production site and harms the production environment.

JP, 2014-87678, A JP, 2006-181027, A

As mentioned above, since the sliding property improvement effect of the silicone oil by the silicone oil is remarkable, even if its use can not be completely eliminated, the contact of the silicone oil with the drug solution is completely done when using the syringe from the above circumstances. There is also a need for a gasket or syringe that can eliminate the application work and improve the working environment at the production site, and that is suitable for automation for mass production. Therefore, the inventors developed a syringe as shown in FIG. 1 in order to solve the above problems. That is, the gasket used in this syringe is a gasket main body formed of a hard plastic resistant to chemical liquid, and a slide using high sliding rubber in the concave groove formed on the sliding surface of the gasket main body against the inner surface of the syringe barrel. We have developed a gasket that has a structure in which the contact ring is fitted.

Initially, a peroxide-curable silicone rubber composition is used as a rubber material of a sliding contact ring, and heat compression molding is performed using a press mold (the silicone rubber composition is put in the press mold and compressed while heating from the top and bottom to cure) Method of manufacturing a sliding ring (see FIG. 6). When a sliding contact ring is formed by this method using a peroxide-curable silicone rubber composition, the following problems occur.
Not only molding could not be carried out when the amount of silicone oil added was too large, but curing was slow, curing was apt to occur, and removal was not possible. In addition, the mold became dirty and continuous molding could not be performed, and the strength of the molded product was low. The peroxide curable silicone rubber is considered to be due to curing failure in the presence of oxygen in the air. Furthermore, the article did not pass the pharmaceutical dissolution test. Therefore, it has been found that peroxide curable silicone rubber compositions can not be used for this application.

In the hot-pressed molded product, the silicone rubber G before curing is pressed by the mold K1, and sheet-like burrs 55 are generated around the cured contact ring semi-finished product 50, and the burrs 55 are cut at the time of cutting. The side surface of the contact ring 19 'may be damaged or the cut 53 may occur to damage the side surface shape. Furthermore, the sliding contact ring 19' immediately after being formed has low slidability and the concave of the gasket main body 26 It is difficult to fit in the groove 18 and can not be used for gasket assembly immediately after molding. The generation of burrs 55 requires a separate burr removal step, and the improvement of slidability requires a heat treatment to promote bleeding of silicone oil from the inner surface, and as described above, gasket assembly takes time and cost. Furthermore, there is also a manufacturing problem that when the assembly of the gasket takes a long time, bacteria enter the gasket 10 and the chances of impurities to adhere increase, so the supply to the assembly process immediately after forming the sliding ring is next. It was an issue of
The present invention has been made in view of this problem, and an object of the present invention is to provide a manufacturing method for manufacturing a sliding contact ring that is optimal for the above-described gasket assembly.
The atomizing silicone oil application process can be eliminated from the manufacturing site by using the sliding ring and further by using a gasket using the sliding ring.

The first aspect relates to a method of manufacturing the bleed type sliding contact ring 19 using silicone rubber G,
Kneading the addition reaction type polysiloxane, the curing catalyst, the silicone oil and the filler to form silicone rubber G before curing;
The silicone rubber G before curing is introduced into the storage space 41 of the mold K,
The silicone rubber G introduced into the storage space 41 is pressed by a plunger 42, and is pressed into the cavity 43 from the gate 44 connecting the storage space 41 and the ring-shaped cavity 43, and flows in the process of press-fitting The surface of the silicone rubber G fluid is filled with the blended silicone oil while being bled,
The silicone rubber G press-fitted in the ring-shaped cavity 43 is cured to form a sliding contact ring 19 on which silicone oil is bled on the surface,
After curing, the sliding ring 19 is taken out of the mold K.

A second aspect relates to the addition reaction type polysiloxane according to the first aspect,
The addition reaction type polysiloxane according to claim 1 is a vinyl group-containing organopolysiloxane and a silicon atom-bonded hydrogen atom-containing organohydrogenpolysiloxane (an organohydro having two or more SiH groups in one molecule as a crosslinker). It is characterized in that it is composed of two agents of genpolysiloxane).

Claim 3 relates to the gate 44 of Claim 1;
The gate 44 is characterized in that it is provided from the storage space 41 side toward the cavity 43 so that the cross-sectional area thereof decreases rapidly or gradually.

Claim 4 relates to the gasket 10 using the sliding contact ring 19,
A gasket main body 26 in which a concave groove 18 is formed on the entire circumference of a sliding contact surface 11 with the inner peripheral surface 2 by being press-fit and used slidably on the inner peripheral surface 2 of the syringe barrel 1;
A sliding contact ring 19 formed by the method according to any one of claims 1 to 3 and fitted in the recessed groove 18 of the gasket main body 26.

Claim 5 is:
The gasket is characterized in that it comprises: a syringe barrel 1; a gasket 10 according to claim 4 which is press-fit into the syringe barrel 1 and used in a sliding state; and a piston rod 5 on which the gasket 10 is mounted. It is a syringe A.

In the method of the present invention, when an addition reaction type polysiloxane is used as the silicone rubber raw material, the curing is very fast, for example, because the curing delay due to oxygen in the cavity is hardly generated. Even if a large amount of silicone oil is added, the formability is not impaired. The addition of a large amount of silicone oil and the early curing property of the addition reaction type polysiloxane make it possible to bleed a suitable amount of silicone oil on the surface of the ring-shaped silicone rubber G pressed in at the time of pressing into the cavity 43. . In other words, the surface bleed of a suitable amount of silicone oil imparts high slidability to the sliding ring 19 immediately after molding. This enables provision of the sliding ring 19 to the gasket assembly process immediately after molding.
This means shortening of the assembly time, and the possibility of contamination contamination and attachment of bacteria in the assembly process can be blocked, and the merit in manufacturing is great.

In addition, if the gate 44 is provided so that the cross-sectional area of the storage space 41 side decreases or gradually decreases toward the cavity 43, the addition reaction type silicone rubber G extruded at high pressure and high speed at the gate outlet 44a is at atmospheric pressure. The inner silicone oil is pushed out to the surface side of the silicone rubber G and forms a silicone oil thin film 19b on the surface of the sliding ring 19 when it is cured. Thus, the sliding ring 19 exhibits the slidability required immediately after formation.

Then, if this sliding contact ring 19 is used to fit in the recessed groove 18 of the gasket main body 26, the application process using the atomized silicone oil which has significantly damaged the working environment in the syringe assembly process conventionally performed It can be eliminated.

It is sectional drawing of the prefilled syringe of this invention. It is a partial expanded sectional view before pressing in a gasket in a syringe. FIG. 2 is a partially enlarged front view shown by a broken line ellipse in FIG. 1; (A) A schematic view of a longitudinal section of a mold used in the present invention, and (b) is a schematic view of an essential part of a transverse section. (A) The top view of the sliding contact ring of this invention, (b) It is the sectional drawing. (A) to (c) a schematic view of a cross section showing a conventional procedure of hot-press forming, (d) a cross section of the molded product, and (e) a deburred product of the molded product. It is a table | surface which shows the difference in the formation method of sliding contact ring (silicone oil only addition), and sliding resistance. It is a table | surface which shows the difference in the formation method of sliding contact ring (silicone oil and ultra-high molecular weight polyethylene fine powder are added), and sliding resistance. It is a sliding resistance measurement result table of the sliding contact ring (silicone oil only addition) of this invention. It is a sliding resistance measurement result table of the sliding contact ring (silicone oil and ultra-high molecular weight polyethylene fine powder addition) of this invention.

Hereinafter, the present invention will be described according to the illustrated embodiments. FIG. 1 is a cross-sectional view of a prefilled syringe A in which a sliding contact ring 19 manufactured by the method of the present invention is used. Although not shown, the sliding ring 19 of the present invention is also applicable to a conventional disposable syringe.
Hereinafter, the prefilled syringe A will be described as a representative example.
As shown in FIG. 1, the prefilled syringe A is composed of a gasket 10, a syringe barrel 1 filled with a drug solution 30, a pilton rod 5 mounted on the gasket 10, and a top cap 8.

The syringe barrel 1 is a cylindrical container, and a mounting portion 1b to which an injection needle (not shown) is mounted is protruded from the tip of the barrel main body 1a, and a finger hooking portion 1c is formed at the rear end. The material of the syringe barrel 1 is hard resin (for example, cycloolefin resin "hereinafter referred to as COP"), polypropylene (hereinafter referred to as PP), ethylene norbornene copolymer (hereinafter referred to as COC), etc. It will be. When the seal width T (see FIG. 3) of the gasket body 26 is 0.1 to 0.6 mm (preferably 0.1 to 0.3 mm), the glass syringe barrel is well adhered to the inner peripheral surface 2 of the syringe barrel. The use of 1 is also possible.

The piston rod 5 is a rod-like member having a male screw 5a at its tip end and a finger rest 5b at its rear end. On the outer peripheral surface of the male screw portion 5a of the piston rod 5, a male screw to be screwed to the female screw hole 15 of the gasket main body 26 described above is engraved. The material of the piston rod 5 is made of a resin such as cyclic polyolefin, polycarbonate or polypropylene.

The top cap 8 is attached to the needle attachment portion 1 b of the syringe barrel 1 to prevent the chemical solution 30 filled in the syringe barrel 1 from leaking and to prevent the chemical solution 30 from being contaminated by bacteria etc. floating in the air. It is a sealing member for The top cap 8 includes a truncated cone-shaped cap body 8a, and a fitting projection 8c formed in the opening direction from the top surface of the cap body 8a and having a recess 8b into which the needle mounting portion 1b is fitted. ing. The top cap 8 is formed of an elastomer in which a chemical resistant film (PTFE or ETFA) is laminated on the inner circumferential surface. The elastomer includes any of "vulcanized rubber", "thermosetting elastomer" or "thermoplastic elastomer".

The main body portion 26 of the gasket 10 shown in FIG. 1 is entirely made of fluororesin, for example, PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), FEP (ethylene tetrafluoride and hexafluoroethylene). Copolymer), PCTFE (polychlorotrifluoroethylene), PVDF (polyvinylidene fluoride), or PP (polypropylene), ultra-high molecular weight polyethylene, COP (cycloolefin polymer), COC (ethylene norbornene) It is formed of a hard material (chemical resistant plastic) which does not react with the chemical solution 30 such as copolymer.
The hard plastic used in the present invention is preferably 70 or more in Shore A hardness (or 40 to 100 in Shore D hardness and 40 to 70 in Rockwell M hardness).

Although PTFE used in the present invention may be pure PTFE, for example, polytetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (abbreviation PFA), which is a crystallization inhibitor of PTFE, tetrafluoroethylene-hexafluoropropylene copolymer It is more preferable to use the modified body in which 1 to 15% by mass of a fluorine resin such as a polymer is mixed to impart elasticity to the main body portion 26 of the gasket 10.
The PTFE used in the present invention may be a pure PTFE or a modified PTFE, or a closed-cell block (round bar) by a hot isostatic pressing method called a so-called HIP treatment.
The PTFE primary sintered block is obtained by compression-molding pure PTFE powder or a powder of a modified PTFE and sintering it. In this sintering, the contact portions of the powders are in close contact with each other, but as a whole, extremely fine gaps are formed in the non-contact portions, and these continuously pass the minute fluid.
When the PTFE primary sintered block is subjected to hot isostatic pressing, the PTFE primary sintered block is compressed to reliably close the ultrafine gaps existing between the particles of the PTFE and to form a closed cell. Hot isostatic pressing under reduced pressure is more effective.

Next, the shape of the gasket 10 of FIG. 1 will be described. The main body portion 26 of the gasket 10 is cylindrical, and a female screw hole 15 for mounting the piston rod 5 is screwed on the rear end face. The portion 17 from the sliding surface 11 to the piston rod mounting surface 17a, which is the rear end surface, is a sliding surface 11 in which the outer peripheral surface on the tip end side of the main body portion 26 slides on the inner peripheral surface 2 of the syringe barrel 1 It is formed in the taper shape which diameter reduces gradually. This portion is called a tapered portion 17. The material of the main body portion 26 is as described above.

A shallow groove 18 is formed in the middle portion of the sliding contact surface 11 of the main body portion 26 over the entire circumference thereof.
In other words, narrow sliding

contact surfaces

11a and 11b are present on both sides of the recessed groove 18, and it is preferable that both sliding

contact surfaces

11a and 11b be liquid tight. Liquid-tightness is imparted to the liquid-contacting side sliding contact surface 11 a adjacent to
That is, a portion having the sliding contact surface 11 a (liquid-contacting side sliding portion 16) is press-fitted to the syringe barrel 1 with a press-fit allowance described later.
A sliding contact ring 19 slidably fitted on the inner peripheral surface 2 of the syringe barrel 1 is fitted in the recessed groove 18. The liquid contact side sliding contact surface 11a will be described later.

“Bleed type silicone rubber G” that makes up the sliding ring 19 uses addition reaction type polysiloxane as a base material, silicone oil and necessary fillings are added to this, and it is kneaded with a kneader, platinum type other It is obtained by adding a curing catalyst, and it is desirable to use for shaping within 5 hours after kneading.
The addition reaction type polysiloxane used in the present invention includes a vinyl group-containing organopolysiloxane and a silicon atom-bonded hydrogen atom-containing organohydrogenpolysiloxane (an organosilicon having two or more SiH groups in one molecule as a crosslinker). (Hydrogenpolysiloxane). The compounding ratio is 1: 0.7 to 1.3 for the former and the latter, and in principle, they are mixed at 1: 1. Both are clay-like substances filled with a predetermined amount of silica powder.
As specific examples of the organohydrogenpolysiloxane, both terminal trimethylsiloxy group-capped methyl hydrogen polysiloxane, both terminal trimethylsiloxy group-capped dimethylsiloxane / methyl hydrogen siloxane copolymer, both terminal dimethylhydrogensiloxy group-capped Dimethyl siloxane, both terminal dimethylhydrogensiloxy group-capped dimethylsiloxane / methylhydrogensiloxane copolymer, both terminal trimethylsiloxy group-capped methyl hydrogen siloxane / diphenylsiloxane copolymer, both terminal trimethylsiloxy group-capped methyl hydrogen siloxane, Diphenylsiloxane / dimethylsiloxane copolymer, copolymer comprising (CH ₃ ) ₂ HSiO _1/2 unit and SiO _4/2 unit, (CH ₃ ) ₂ HSiO _{1 / 2} units and the SiO _4/2 units (C6 H5) such as copolymers comprising SiO _3/2 units and the like.

The curing catalyst (addition reaction catalyst) used in the present invention includes platinum black, platinum chloride, chloroplatinic acid, reaction product of chloroplatinic acid and monohydric alcohol, complex of chloroplatinic acid and olefins, platinum Platinum-based catalysts such as bisacetoacetate, palladium-based catalysts, rhodium-based catalysts, tin and the like can be mentioned.

Silicone oils are generally colorless and transparent liquids, and are excellent in heat resistance, cold resistance, water resistance, and have less viscosity change over a wide temperature range. In addition, it also has releasability, water repellency, antifoaming properties, lubricity and the like. For the application of the present invention, higher viscosity is preferable, and viscosity which is an index of molecular weight is in the range of 1,000 to 1,000,000 cP, more preferably, about 50,000 to 200,000 cP causes bleeding. Preferred above.
As mentioned above, there is compatibility between silicone rubber G, which is based on addition reaction type polysiloxane and to which necessary filler is added, and silicone oil which has been kneaded, and if it is filled in a suitable amount, silicone oil is It disperses uniformly in silicone rubber G.

As a filler, fine powder silica is used. Examples of the finely powdered silica include fumed silica, sintered silica, precipitated silica and the like, and these may be used singly or in combination of two or more. The blending amount of the components is preferably 10 to 100 parts by weight, and more preferably 10 to 50 parts by weight with respect to 100 parts by weight of the organopolysiloxane. If the blending amount is too small or too large, the processability of the resulting silicone rubber composition is reduced, and sufficient mechanical strength of the resulting cured product can not be obtained.

Other fillers include ultra-high molecular weight polyethylene fine powder. The average molecular weight is 1,000,000 to 3,000,000, and some reach 7,000,000. The ultra-high-molecular-weight polyethylene fine powder has no water permeability and does not adhere to most particles, and because its molecular weight is too high, it does not melt even at high temperatures, and retains its spherical form even when molded at high pressure. Although the surface of the spherical ultra-high molecular weight polyethylene is relatively smooth, some irregularities are also observed. The range of the particle size of the spherical ultrapolymer fine particles contained in the fine powder is 10 to 300 μm. When the width of the particle size distribution is wide, small particle diameter particles get in between the large particle diameter particles to fill gaps between the large particle diameter particles, thereby achieving fine packing. When finely packed, the bleed-type silicone rubber as a whole exhibits very low water permeability. The ultrahigh molecular weight polyethylene fine powder is used to adjust the hardness of the molded article, and is added as necessary.

A mold K is a storage space 41, a ring-shaped cavity 43 (one is shown in the figure, but a plurality of molds can be provided around the storage space 41, and a large number of pieces can be taken), a storage space 41. And a ring-shaped cavity 43 and a plunger 44. The gate 44 is provided from the side of the storage space 41 toward the cavity 43 so that the cross-sectional area thereof rapidly decreases or gradually decreases.
Here, the fact that the cross-sectional area of the gate 44 sharply decreases is the case where the gate outlet 44a is narrowed stepwise. The gradual decrease is the case where the inner surface of the gate 44 is smoothly tapered so as to gradually decrease toward the cavity 43.

And the said raw material was mixed in the predetermined ratio, and it knead | mixed with a kneader, and formed silicone rubber G before hardening. When the silicone rubber G before curing is put into the storage space 41 of the mold K and the silicone rubber G put into the storage space 41 is pressed by the plunger 42, the silicone rubber G is pushed out from the gate 44 under high pressure. Be Since the gate 44 is provided toward the cavity 43 so as to sharply reduce or gradually reduce the cross sectional area as described above, the silicone rubber G is gradually pushed out at high pressure and high speed as it approaches the gate outlet 44 a of the gate 44. Upon leaving the gate outlet 44a, the silicone rubber G compressed to a high pressure is pushed into the cavity 43 held at atmospheric pressure and is rapidly depressurized.
Since a large amount of silicone oil is added to the silicone rubber G, part of the silicone rubber G is pushed out and bled onto the surface of the soft silicone rubber G before curing.
The uncured silicone rubber G extruded into the ring-shaped cavity 43 diverges from both sides of the gate outlet 44a, and collides at high speed on the opposite side of the gate outlet 44a of the cavity 43 without forming a weld surface. Construct an integral ring. At this time, an appropriate amount of silicone oil thin film 19 b is formed on the surface of the sliding contact ring 19 formed in a ring shape before curing.
In this state, the sliding ring 19 is hardened by holding for a predetermined time. After curing, the mold K is opened and only the sliding ring 19 is taken out. At this point, the surface of the sliding ring 19 is taken out in the state of being covered by the silicone oil thin film 19b.

The sliding ring 19 formed in this manner is fitted into the recessed groove 18 of the gasket body 26. Since the silicone oil thin film 19b exists on the surface of the sliding contact ring 19, the mounting operation is completed smoothly. When the assembly of the gasket 10 is completed, the piston rod 5 is attached to the gasket 10 and the gasket 10 is pressed into the syringe barrel 1 to assemble the syringe A. In the case of the prefilled syringe A, the liquid medicine 30 is filled into the syringe barrel 1 after or during the assembly.

As a result, simplification and time reduction of the syringe assembly process, and the atomization silicone oil application process which has been considered to be essential conventionally can be eliminated from the syringe assembly process.

(Example)
7 and 8 are tables showing the difference between the method of forming the sliding contact ring and the sliding resistance. FIG. 7 shows that to which only silicone oil is added, and FIG. 8 shows that to which silicone oil and ultra-high molecular weight polyethylene fine powder are added. The sliding contact ring was fitted to the gasket and its slidability was evaluated.
The sliding performance of the syringe was evaluated by the following experiment. (Unit is mm)
Syringe shape (for 1 ml)
Inner diameter: 6.35, moving length of gasket: 35
Gasket shape Gasket body Outer diameter: 6.47, shape of concave groove: groove width 1.6 diameter 5.15
Sealing width of contact side sliding surface: 0.3
Material: Polytetrafluoroethylene Slide ring shape Thickness: 1.55, outer diameter: 6.20, inner diameter: 4.5
Gasket sliding condition: 82 mm / min Sliding distance: 35 mm
Material of sliding contact ring: A sliding contact ring was formed using 25% by weight of silica powder and 10% by weight of silicone oil added to polydimethylsiloxane.
Compression molding sample (see FIG. 6): A molding material is introduced using a mold in which the shape of the sliding contact ring is processed, and heat and pressure molding is performed. After molding, the surplus burrs protruding from the shape portion of the sliding contact ring were punched out.
Differential pressure molded sample (transfer molded product shown in FIG. 4): A cavity in which the shape of the sliding contact ring is processed and a mold in which the shape of the input portion (gate) to the cavity is a circle with a diameter of 0.3 mm Use The shape of the material feeding portion (storage space) is 12 mm in diameter, and the pressing force is 0.5 MPa.
● Test results: In the slideability evaluation test immediately after setting the syringe, the gasket in which the sliding contact ring formed by differential pressure molding was fitted showed a slideability smaller than the other molding methods.

In the evaluation of FIG. 8, the gasket body and the sliding ring used were of the same shape as that of FIG. 7.
Material of sliding contact ring: A sliding contact ring was formed by using 25% by weight of silica powder, 20% by weight of silicone oil and 20% by weight of ultra-high molecular weight polyethylene fine powder added to polydimethylsiloxane.
The molding conditions are the same as in FIG.
● Test results: In the slideability evaluation test immediately after setting the syringe, the gasket in which the sliding contact ring formed by differential pressure molding was fitted showed a slideability smaller than the other molding methods.

FIG. 9 and FIG. 10 are tables showing differences in additives of the sliding contact ring. The molded articles were all formed by a differential pressure molding method.
FIG. 9 shows the case where only silicone oil is added, and FIG. 10 shows the case where silicone oil and ultra-high molecular weight polyethylene fine powder are added. The sliding contact ring was fitted to the gasket and its sliding property was evaluated.
In the evaluation of FIG. 9, the gasket body and the sliding ring used were of the same shape as that of FIG.
Material of sliding contact ring: 25% by weight of silica powder added to polydimethylsiloxane and kneaded (without addition of silicone oil) is regarded as a substrate 1 (comparative example), with a viscosity of 1,000 cP and a viscosity of 100 Preparations (Examples 1 to 3) were prepared by adding 5, 10 and 15% by weight of silicone oils having a viscosity of 1,000 cP and a viscosity of 1,000,000 cP, respectively, and changing the average sliding resistance value of the sliding contact ring immediately after molding Was measured. (There is no addition of ultra-high molecular weight polyethylene powder in Comparative Example and Examples 1 to 3 here.)
In FIG. 9, the content of the silicone oil is limited to a maximum of 15% by weight since no ultrahigh molecular weight polyethylene powder is added. Addition of silicone oil in excess of 15% by weight makes molding difficult. Below 5% by weight, the sliding resistance exceeds the target 7N. The usable range of the syringe immediately after assembly is 5 to 15% by weight.
Measurement results show that all syringes immediately after assembly using silicone oil with 5% by weight to 15% by weight of sliding contact ring use showed an average sliding resistance of 7 N (unit Newton) or less.

Evaluation of slidability by addition of ultra-high molecular weight polyethylene powder (Fig. 10)
In the evaluation of FIG. 10, the gasket main body and the sliding ring used had the same shape as that of FIG. In this examination, a base material (hereinafter referred to as base material 2) in which 13.13 g of polydimethylsiloxane, 4.37 g of silica powder as filler, and 23.35 g of ultra-high molecular weight polyethylene powder (20 to 200 μm) are mixed. On the other hand, various silicone oils with a viscosity of 1,000 to 1,000,000 cP are added to polydimethylsiloxane oils of various degrees of polymerization (hereinafter referred to as silicone oils, the viscosity of which is represented by cP as an index of the degree of polymerization) The relationship between the amount added and the sliding resistance was measured.
The ultrahigh molecular weight polyethylene powder has high affinity to silicone oil, and the addition amount of the silicone oil can be increased, and the hardness of the sliding ring can be increased by the addition of the ultrahigh molecular weight polyethylene powder. Silicone oil could be added up to 5 to 40% by weight.
In this case, the addition amount of silicone oil was 5 to 40% by weight, and the sliding resistance was below the target 7 N at all the viscosity. If it is less than 5% by weight, it exceeds the target 7N. In addition, molding was difficult in the addition amount exceeding 40% by weight.
A silicone oil having a viscosity of 1,000 cP can not be molded if it exceeds 30% by weight. The optimum amount of silicone oil added in this case is around 20% by weight.

A: pre-filled syringe, G: silicone rubber, K · K1: mold, T: seal width, 1: syringe barrel, 1a: barrel body, 1b: needle mounting portion, 1c: collar portion, 2: inner circumferential surface, 5 : Piston rod, 5a: Male thread, 5b: Finger rest, 8: Top cap, 8a: Cap body, 8b: Recess, 8c: Fitting projection, 10: Gasket, 11: Sliding surface, 11a: Contact Liquid surface side sliding contact surface (liquid contact side sliding contact surface), 11b: Piston rod side sliding surface (rod side sliding contact surface), 14: Liquid contact surface, 15: Female screw hole, 16: Liquid contact side Sliding part, 17: Tapered part, 17a: Mounting surface of piston rod, 18: Concave groove, 19 · 19 ′: Sliding ring, 19b: Silicone oil film, 26: Body part (gasket body), 30: Chemical solution, 31: drug, 41: storage space, 42: plunger, 43: cavity Tee, 44: Gate, 44a: Gate exit, 48: Runner, 50: Semifinished product, 53: Leave uncut, 54: Scratch, 55: Burr.

Claims

Kneading the addition reaction type polysiloxane, the curing catalyst, the silicone oil, and the filler to form silicone rubber before curing;
The silicone rubber before curing is introduced into the mold storage space,
The silicone rubber introduced into the storage space is pressed by a plunger and pressed into the cavity from the gate connecting the storage space and the ring-shaped cavity, and the surface of the silicone rubber fluid flowing in the process of being pressed in To bleed while being blended with the formulated silicone oil,
Curing the silicone rubber pressed in the ring-shaped cavity to form a sliding ring in which silicone oil is bled on the surface;
A method of manufacturing a bleed type sliding contact ring characterized by removing the sliding contact ring from a mold after curing.
2. The bleed-type contact ring according to claim 1, wherein the addition reaction type polysiloxane is composed of a vinyl group-containing organopolysiloxane and a silicon atom-bonded hydrogen atom-containing organohydrogenpolysiloxane. Production method.
The method for manufacturing a bleed type sliding contact ring according to claim 1, wherein the gate is provided from the side of the storage space toward the cavity so that the cross-sectional area thereof rapidly decreases or gradually decreases.
A gasket body which is used by being press-fitted slidably on the inner peripheral surface of the syringe barrel and in which a recessed groove is formed on the entire circumference of the sliding contact surface with the inner peripheral surface;
A gasket comprising: a sliding contact ring formed by the method according to any one of claims 1 to 3 and fitted in a recessed groove of a gasket body.
A syringe comprising: a syringe barrel; a gasket according to claim 4, which is press-fitted into the syringe barrel and used in a sliding state; and a piston rod on which the gasket is mounted.