JP2005297432A - Stopper manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a stopper enhanced in the adhesiveness of a leg and a cap by a double-step molding method for molding the leg of the stopper and subsequently molding the cap thereof. <P>SOLUTION: In the manufacturing method of the stopper 6 by the double-step molding method for molding the leg 4 and subsequently molding the cap 5 while bounding the same to the leg 4, a film 3, which comprises a polymer alloy composed of a polymer selected from a group composed of olefinic plastic and synthetic rubber and at least one of thermoplastic elastomers is held between the leg 4 and the cap 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing a plug used as a stopper having elasticity in a mouth of a container such as a pharmaceutical product, a medical instrument part, a medical instrument, etc., and after forming a leg part of the plug The present invention relates to a two-stage molding method for molding a part.

  In order to hold a medicine by a medicine container, the container portion is usually made of glass or plastic material, and the mouth portion is usually stoppered with an elastic stopper. As shown in FIGS. 3 and 4, the plug body that closes the container mouth portion is generally in contact with the leg portion 14 to be inserted in contact with the inner wall of the container mouth 18 and the upper portion of the container mouth 18. It has a cap portion 15. In such a plug body 16, the leg portion 14 comes into contact with the contents such as pharmaceuticals enclosed in the container, and therefore, only the leg portion 14 is provided with a laminate 12 on the rubber cloth 11 (patent) In many cases, different materials are used for the leg and the cap (see Patent Document 3). In such a case, since the leg portion and the cap portion cannot be molded integrally at a time, a two-stage molding method is used in which the leg portion is first molded and then the cap portion is molded while being bonded to the leg portion (Patent Document 1). To 3).

JP 2000-202837 A JP 57-47637 A JP 2000-279485 A

When the cap portion is formed by injection or compression in the two-stage forming method of the plug body, the material may be different between the leg portion and the cap portion. Even when the same material is used, for example, when butyl rubber or the like is used, the rubber fabric of the legs is already vulcanized and cross-linked at the time of molding of the caps. There was a demand for improvement.
In recent years, in the case of rubber plugs for pharmaceutical applications, there has been a tendency to reduce inorganic compounds such as talc, clay, silica, etc. due to demand for elution control, etc. There are increasing factors that worsen the adhesion of the cap.
Accordingly, an object of the present invention is to provide a method of manufacturing a plug body in which the leg portion and the cap portion have high adhesiveness in a two-stage molding method in which the cap portion is molded and then the cap portion is molded.

As a result of intensive studies in view of the above problems, the present inventors have found that when forming a cap portion of a plug body, a specific polymer alloy film is sandwiched between the leg portion, so that the film has a leg portion and a cap portion. The present inventors have found that a plug having an adhesive action and sufficiently bonded to each other can be obtained, and the present invention has been made based on this finding.
That is, the present invention has the following configuration.
(1) In a method of manufacturing a plug by a two-stage molding method in which a leg portion is molded and then bonded to the cap portion, the cap body is formed of an olefin plastic and a synthetic rubber between the leg portion and the cap portion. A plug production method comprising sandwiching a film made of a polymer alloy comprising at least one selected from the group and at least one selected from thermoplastic elastomers.
(2) The method for producing a plug according to (1), wherein the film has heat resistance of a melting temperature of 125 ° C. or higher.
(3) The method for producing a plug according to (1) or (2), wherein the film has a thickness of 50 to 200 μm.
(4) The method for manufacturing a plug according to any one of (1) to (3), wherein the film is a polymer alloy film having an interpenetrating network structure.
(5) The method for manufacturing a plug according to any one of (1) to (4), wherein the film is adhered to the leg portion and the cap portion during cross-linking molding.

  According to the manufacturing method of the present invention, it is possible to provide a plug in which the leg portion and the cap portion are sufficiently bonded even when the leg portion and the cap portion are not made of the same material or when the leg portion has a laminate only. .

The manufacturing method of the plug of the present invention can be applied to any manufacturing method as long as it is a two-stage molding method in which the cap portion is molded after the leg portion is molded, and compression molding is applied to each of the leg portion and the cap portion. Alternatively, it may be injection molding. Also, the material can be appropriately selected from ordinary vulcanized rubber (natural rubber, synthetic rubber such as isoprene rubber (IR) and isobutylene isoprene rubber (IIR)), thermoplastic elastomer, plastic, etc. The parts may be the same or different. Furthermore, the leg part and / or the shade part may have a laminate.
In addition, since the plug obtained by the method of the present invention is manufactured by a two-stage molding method, the combination of the manufacturing method and the material cannot be integrally molded at one time. Are different or only one of the cap and the leg is laminated.

In the method for manufacturing a plug of the present invention, a leg portion having a film of a specific composition adhered to the top surface is formed, and the cap portion is formed by sandwiching the film between the cap portion and the leg portion. Is preferred. This is because the film can be bonded with high strength by bonding the legs and the cap at the time of cross-linking molding.
The film comprises at least one selected from thermoplastic elastomers and at least one polymer alloy selected from olefin plastics and synthetic rubbers.
Examples of the thermoplastic elastomer include styrene-ethylene-butadiene copolymer (SEBS), styrene-butadiene-ethylene block copolymer (SBS), and styrene-isoprene copolymer (SIS). In SEBS, “Clayton” (trade name, manufactured by Clayton Polymer Co., Ltd.), “Tufprene” (trade name, manufactured by Asahi Kasei Kogyo Co., Ltd.) and the like can be used as commercial products.
Examples of the olefin plastic include general-purpose resins such as polyethylene (PE) resin and polypropylene (PP) resin, and copolymers of these and polymers having polar groups (acrylic group, vinyl group, ester group, halogen, etc.), Ethylene vinyl acetate copolymer, other copolymers with one or more α-olefins such as 1-butene, 1-pentene, 4-methyl-1-pentene, ethylene or the main component of these α-olefins And vinyl esters, unsaturated carboxylic acids or copolymers thereof with polymers thereof.
As the synthetic rubber, nitrile rubber and urethane rubber are preferable. As the olefin plastic and / or synthetic rubber, those having an acrylic group are particularly preferable.
The ratio of the thermoplastic elastomer to the olefin plastic and / or synthetic rubber is appropriately selected depending on the material of the leg portion and the cap portion, but is preferably 1: 3 to 9: 1 by weight ratio. The polymer alloying technology includes compatible polymer alloys in which different types of polymers are mixed in the form of molecules, phase-separated polymer alloys of polymers having different properties, and two or more different types of polymer chains being covalently linked to each other. There is a polymer alloy having an interpenetrating network (IPN) structure in which the same kind of polymers are cross-linked with each other, and among them, a polymer alloy having an IPN structure is particularly suitable for heat resistance and physical properties (molding). In terms of properties, adhesiveness, etc.).
In addition, carbon, titanium, a silicon compound, etc. can also be added to a polymer alloy film as needed in order to improve heat resistance more.
By using the film having the above composition, the film is heated and compressed between the cap portion and the leg portion at the time of forming the cap portion, so that the cap portion and the leg portion are bonded.

The film exhibits an adhesive action by heat compression, and requires heat resistance for heat treatment such as sterilization after it becomes a plug, and therefore preferably has a melting temperature of 125 ° C. or more, more preferably One having a temperature of 130 ° C. or higher, particularly preferably 130 to 150 ° C. is used.
The film thickness of the film is preferably 50 to 200 μm, more preferably 70 to 140 μm in view of adhesive performance and economy.

Next, the present invention will be described in more detail with reference to examples. The present invention is not limited to the materials, compositions, and production methods described in the following examples.
(Example 1)
A rubber stopper having the legs laminated by the two-stage molding method shown in FIG. 1 was produced.
First, using a lower mold 21 having leg forming recesses 22, a 0.1 mm thick fluorine-based resin film 2 ′, a 4 mm thick non-toxic uncrosslinked butyl rubber sheet 1 ′, a 0.1 mm thick polymer alloy film 3. ′ (Composition: 60% by weight of SEBS, 20% by weight of polyacrylonitrile, 20% by weight of polypropylene, having an interpenetrating network structure) is sequentially polymerized, and then heated and heated with the upper mold 23 at normal temperature and pressure. Thus, a leg base body whose lower surface is covered with the resin layer 2 and whose upper surface is the polymer alloy film layer 3 is formed (FIG. 1B).
Next, the element body is cut with a cutting device to form legs 4 (FIG. 1C).
Next, a non-toxic non-crosslinked rubber sheet 5 ′ having a thickness of 4 mm is sequentially polymerized on the upper surface of the legs 4 filled in the lower mold 21, and heated and pressurized with the upper mold 24 at a normal temperature and pressure. (FIG. 1 (e)), predetermined cutting was performed to produce a plug 6 in which the film layer 3 made of polymer alloy was sandwiched between the leg 4 and the cap 5 (FIG. 1 (f)). FIG. 1 (g) shows an explanatory diagram of a state when the stopper 6 is inserted into the container mouth 18.

(Example 2)
In the same manner as shown in FIGS. 1A to 1C in Example 1, the leg plug 4 shown in the sectional view and the perspective view in FIG.
This is set in the cavity of the lower injection mold 31, and the material SEBS elastomer of the cap portion is injected from the upper press mold 33 into the space of the upper injection mold 32 and pressurized (FIG. 2 (b)). The plug body 6 as shown in a partially sectional perspective view in FIG. 2A to 2C, the same reference numerals as those in FIGS. 1A to 1F denote the same components.

(Comparative Example 1)
Except not using a polymer alloy film, the plug body which has a leg part and a cap part in the same manner as Example 1 was manufactured by the two-step molding method.

(Test example)
About 20 plug bodies manufactured in Example 1 and 20 plug bodies manufactured in Comparative Example 1, the adhesion between the leg portions and the leg portions was measured by the following method.
(1) Hold the cap of the rubber stopper with a vise and grasp the leg of the rubber stopper with pliers.
(2) Attach a PUSH-PULL Scale (made by Imada Seisakusho) to the pliers and pull until either the cap or leg piece of rubber cap breaks or peels off. The strength (kgf) value at this time is measured.
The results are shown in Table 1. The plug of Example 1 had a maximum value of 5.10 kgf, a minimum value of 3.80 kgf, and an average value of 4.29 kgf, whereas the plug of Comparative Example 1 had a maximum value of 3.20 kgf and a minimum value of 1.55 kgf, The average value was 2.58 kgf, and the plug of Example 1 had much higher adhesion between the leg and the cap.

It is explanatory drawing which shows typically an example of the manufacturing method of the plug body of this invention. (Example 1) It is explanatory drawing which shows typically another example of the manufacturing method of the plug body of this invention. (Example 2) It is a partial cross section perspective view which shows the conventional stopper. It is explanatory drawing which shows the state by which the stopper shown in FIG. 3 is inserted in the container opening part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rubber | gum 1 ', 5' Rubber | gum fabric 2 Laminate layer 2 'Resin film 3 Polymer alloy film layer 3' Polymer alloy film 4, 14 Leg part 5, 15 Cap part 6, 16 Cap body 18 Container mouth part 21 Lower mold 22 Leg forming recess 23 Upper mold 24 Upper mold 31 Injection lower mold 32 Injection upper mold 33 Press upper mold

Claims (5)

  In the manufacturing method of the plug body by the two-stage molding method, after forming the leg part and then forming the cap part while adhering to the leg part, between the leg part and the cap part, selected from the group consisting of olefin plastic and synthetic rubber A method for producing a plug, comprising sandwiching a film made of a polymer alloy comprising at least one selected from thermoplastic elastomers.   The method for producing a plug according to claim 1, wherein the film has heat resistance of a melting temperature of 125 ° C. or higher.   The method for producing a plug according to claim 1 or 2, wherein the film has a thickness of 50 to 200 µm.   The method for manufacturing a plug according to any one of claims 1 to 3, wherein the film is a polymer alloy film having an interpenetrating network structure. The said film adhere | attaches the said leg part and the said cap part at the time of bridge forming, The manufacturing method of the plug body of any one of Claims 1-4 characterized by the above-mentioned.

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