JP5282326B2 - Seal plug using hygroscopic laminate - Google Patents

Description

The present invention relates to a sealing stopper used for a container for storing an article that is liable to be deteriorated in quality due to moisture absorption in a dry state.

  For example, Patent Documents 1 and 2 include polyethylene as a moisture absorption layer as a laminate or container for storing food or pharmaceuticals whose contents are liable to be deteriorated due to moisture absorption as contents. A laminate in which layers such as polyolefin, aluminum foil, and polyester resin are arranged is disclosed.

Japanese Patent No. 2885079 JP 2004-143310 A

  In the laminated body having the moisture absorption performance, not only the laminated body of Patent Documents 1 and 2, a protective layer is provided for protecting the moisture absorbing layer so that the moisture absorbent contained in the moisture absorbing layer does not directly contact the contents. In general, resin such as polyolefin is used although it depends on the contents and the form of the package.

  However, the initial moisture absorption rate may be affected by the provision of a protective layer, which is not a problem for contents that do not stick to the moisture absorption rate. In some cases, further improvement of the initial moisture absorption rate has been desired.

  Further, depending on the form to be used, it may be necessary to form a tubular tube, and the material used for the protective layer needs to be considered for moldability.

  The present invention has been made in view of the circumstances as described above, and has a basic performance as a protective layer for a hygroscopic layer, and a protective layer and a hygroscopic layer excellent in initial moisture absorption speed and moldability. And a sealing plug using the same.

The sealing plug according to the present invention has a configuration using a laminate including a hygroscopic layer made of polyolefin and zeolite and a protective layer made of a thermoplastic elastomer.

More specifically, the sealing plug in the present invention is:
A substrate having a through-hole, a side wall portion that hangs in a cylindrical shape from the substrate, and a laminate that is held on the inner side surface of the side wall portion,
The laminate is a cylinder composed of a hygroscopic layer and a protective layer, and has a protective layer on the side in contact with the contents,
The moisture absorption layer is made of polyolefin and zeolite,
The protective layer is made of a thermoplastic elastomer,
The thermoplastic elastomer is a styrenic thermoplastic elastomer,
Or it is set as the sealing stopper which consists of a polymer of polyolefin resin and silicone.

Moreover, in this invention, it is set as the sealing stopper provided with said laminated body by 3 layer structure of a protective layer / hygroscopic layer / protective layer.

  According to the present invention as described above, the initial moisture absorption rate can be improved, so that the contents that are liable to be deteriorated due to moisture absorption can be stored in a dry state, and the contact between the moisture absorbent and the contents. Can be prevented appropriately.

It is a schematic sectional drawing which shows one Embodiment of the sealing stopper and sealing container which concern on this invention. It is a schematic sectional drawing which shows one Embodiment of the laminated body sheet which concerns on this invention. It is a schematic sectional drawing which shows one Embodiment of the sealing stopper which concerns on this invention.

Hereinafter, preferred embodiments of the present invention will be described in detail.
The laminate used for the sealing plug of the present invention has a structure comprising a hygroscopic layer made of polyolefin and zeolite and a protective layer made of a thermoplastic elastomer.

[Protective layer]
The thermoplastic elastomer (TPE) used for the protective layer of the present invention comprises a soft segment having rubber elasticity in the molecule and a hard segment that prevents plastic deformation. Thermoplastic elastomers are suitable for the present invention because they can be used with ordinary thermoplastic resin molding machines and are easy to mold.
Thermoplastic elastomers include styrene thermoplastic elastomer (SBC), olefin thermoplastic elastomer (TPO), urethane thermoplastic elastomer (TPU), ester thermoplastic elastomer (TPEE), and amide thermoplastic elastomer (TPAE). , PVC-based thermoplastic elastomer (TPVC), silicone-based thermoplastic elastomer, and resin-polymerized silicone. These may be used alone or in combination of two or more.
In the present invention, a styrene thermoplastic elastomer or resin (particularly polyolefin resin) obtained by polymerizing silicone is preferably used.

  Styrenic thermoplastic elastomer refers to a thermoplastic elastomer containing styrene, a homologue thereof or an analogue thereof. What is known as a styrenic thermoplastic elastomer can be used without particular limitation. As a specific example, a block copolymer containing a block of styrene, a homologue thereof or an analogue thereof as at least one terminal block and at least one elastomer block of a conjugated diene or a hydrogenated product thereof as an intermediate block Can be mentioned.

Specific examples of the styrene-based thermoplastic elastomer include polystyrene-polybutadiene-polystyrene (SBS), polystyrene-polyethylene / polybutylene-polystyrene (SEBS), polystyrene-polyisoprene-polystyrene (SIS), polystyrene-polyethylene / It is divided into polypropylene-polystyrene (SEPS) and the like, and there are types such as a linear triblock, a radial block, and a multiblock depending on the coupling mode of the hard segment and the soft segment.
In the present invention, SEBS (polystyrene-polyethylene / polybutylene-polystyrene) which is a hydrogenated product of styrene-butadiene-styrene block copolymer is suitable.

  SEBS is excellent in heat resistance and weather resistance, and also has oil resistance. Moreover, since it is easy to process, injection molding and extrusion molding are possible, and it can be applied to various forms of packaging bodies. Furthermore, it is applicable to medical and food hygiene.

A polymer of resin and silicone is a polymer obtained by graft-polymerizing silicone to a base resin, and more specifically, a polymer produced by graft-polymerizing reactive polyorganosiloxane to various resins. is there.
In the present invention, a polyolefin-based resin is suitable for the base resin, such as very low density polyethylene (VLDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and high density polyethylene (HDPE). ), Polypropylene (PP), polymer alloy of PP (reactor PP), ethylene-propylene rubber (EPR), ethylene-methyl methacrylate copolymer (EMMA), ethylene-vinyl acetate copolymer (EVA), ethylene -Acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMA), etc. are mentioned, Said resin may be individual, and what blended 2 or more types may be used.
Moreover, it is preferable that the content rate of silicone is 30 to 80 weight% with respect to base resin.

[Hygroscopic layer]
The hygroscopic layer of the present invention comprises a thermoplastic resin and a hygroscopic agent, and a polyolefin resin, a polyester resin, a polyamide resin, or the like can be used as the thermoplastic resin.
In the present invention, polyolefin-based resins can be preferably used. Specifically, low-density polyethylene, linear low-density polyethylene, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-methacrylic acid. An acid copolymer etc. are mentioned.

As the hygroscopic agent, known ones such as zeolite, magnesium sulfate, silica, calcium oxide, calcium chloride can be used, but in the present invention, zeolite can be preferably used, and the hygroscopic layer is formed by blending with the above thermoplastic resin. To do.
The zeolite blended as the hygroscopic material preferably has an average particle size of 5 to 70 μm. When it exceeds 70 μm, the total surface area becomes small, and it tends to be difficult to obtain a desired moisture absorption function. On the other hand, if it is less than 5 μm, it tends to condense and secondary particles having a large diameter are produced, and the total surface area tends to be reduced. Moreover, it is preferable that the compounding quantity of a zeolite is 0.1 to 50 weight%. When it exceeds 50% by weight, the moisture absorption is too large and the foam tends to be easily foamed. On the other hand, if it is less than 0.1% by weight, it tends to be difficult to obtain a desired moisture absorption function.
In addition to zeolite, additives such as antioxidants and lubricants may be appropriately blended in the resin material forming the moisture absorption layer as necessary.

[Laminate]
The laminated body of this invention has the structure which has a moisture absorption layer and a protective layer, and a protective layer exists in the side which contacts a content. An adhesive resin layer may be provided between the hygroscopic layer and the protective layer, or the hygroscopic layer may be sandwiched between protective layers to form a three-layer structure.
The thickness of the protective layer may be as long as necessary to prevent the contents from directly touching the moisture absorption layer, but it is necessary to ensure the initial moisture absorption rate, so that the thickness is at least about 5 to 50 μm. Preferably formed.

In the laminate of the present invention, layers having various functions may be further laminated on the outer layer.
As a layer having other functions, for example, an arbitrary layer such as a thermoplastic resin layer, a barrier layer that blocks oxygen and moisture, an oxygen absorption layer, a paper layer, and the like can be provided.
Examples of the thermoplastic resin layer constituting the outer layer include polyolefins such as low density polyethylene, high density polyethylene, and polypropylene, polyamides such as nylon 6, and polyesters such as polyethylene terephthalate and polyethylene naphthalate.

Examples of the barrier layer include a metal foil, a gas barrier resin, an inorganic vapor deposition layer, and a gas barrier coating layer. Examples of the metal foil include light metal foils such as aluminum and aluminum alloys, steel foils such as iron foil, tin foil, and surface-treated steel foil.
The gas barrier resin is preferably a thermoplastic resin having a low oxygen permeability coefficient and thermoforming, and examples thereof include ethylene-vinyl alcohol copolymers and polyamides. Moreover, as an inorganic vapor deposition layer, vapor deposition layers, such as a silica and an alumina by CVD and PVD method, are mentioned. Examples of the gas barrier coating include coatings such as PVDC and PVA.

The laminate of the present invention may be used in a container containing an article, or may be used by being attached to a container body or a lid. In this case, the laminate may be formed into a sheet shape or a tube shape.
Moreover, you may process and use the laminated body of this invention for a package. Specific examples of the package using the laminate include, for example, a package using a film or a sheet, containers such as a cup, a tray, a bottle, and a tube.
The bottle or tube is extruded from the parison, then pinched off the parison with a pair of split molds, and direct blow molding that blows fluid into the inside of the bottle or tube. Also, the preform is injection molded, the preform is cooled, and then heated to the stretching temperature. In addition, the film is stretched in the axial direction and molded by biaxial stretch blow molding in which the fluid pressure blows in the circumferential direction. The cup or tray-like container is formed by means such as vacuum forming, pressure forming, stretch forming, plug assist forming, etc., of a film or sheet.

[Sealing stopper]
One embodiment of the sealing plug of the present invention is shown in FIG.
In the example of the sealing plug shown in FIG. 1, the sealing plug 1 has a configuration in which the laminate 10 of the present invention is provided inside a sealing plug body 20. The sealing plug body 20 includes a disk-shaped substrate 21 and a side wall portion 22 that hangs down from the substrate 21 in a cylindrical shape. A through hole 21a is formed in a circular shape substantially at the center of the substrate 21, and the side wall portion 22 hangs coaxially with the through hole 21a. When the opening of the container body 40 is sealed with the sealing plug 1, the lower surface of the substrate 21 positioned on the outer peripheral side of the side wall portion 22 is in contact with the flange portion 41 formed in the opening of the container body 40. It is supposed to be.
Moreover, the laminated body 10 of the present invention is held on the inner side surface of the side wall portion 22 provided to hang down from the sealing plug 1. Thereby, the hygroscopic function for maintaining the dry state of the contents 50 accommodated in the container body 40 is given to the sealing plug 1.

The laminate 10 has a cylindrical shape and is provided with a protective layer on the inside. When the side wall of the sealing plug has a cylindrical shape, the hygroscopic layer and the protective layer have a two-layer structure. However, in order to further improve the hygroscopic performance, the protective layer / It is preferable to have a three-layer structure of a moisture absorption layer / protective layer.
The laminate 10 is formed by forming into a tube shape by multi-layer coextrusion and cutting to a predetermined size.

The fitting between the sealing plug 1 and the container 40 enables the sealing with a stopper by setting the diameter of the side wall portion to a predetermined dimension. Further, the side wall portion or the flange portion may be sealed using an O-ring or the like, or the flange lower surface of the sealing plug 1 and the opening top surface of the container body may be melt bonded by heat sealing. Furthermore, a rubber sealing agent or the like can be applied and caulked with an aluminum cap or the like. Furthermore, the sealing stopper and the container may be fitted with screws.

Further, a through hole 21 a is formed in the substrate 21 of the sealing plug 1, and this through hole 21 a is closed by a sealing member 23 attached to the top surface side of the substrate 21 of the sealing plug 1. As the seal member 23, a metal foil such as an aluminum foil having a low moisture permeability and an excellent gas barrier property is preferably used.
The sealed container in which the opening of the container body 40 is sealed by the sealing plug 1 can be opened by tearing the seal member 23 by piercing a hollow cylindrical member having a sharp tip such as an injection needle. it can. Then, the contents can be taken out by suction or the like through the cylindrical member inserted into the container. Thereby, it is possible to effectively avoid contamination of foreign matters (scrap pieces of stoppers), which has been regarded as a problem in a vial sealed with a conventional stopper.

The sealing plug body is made into a predetermined shape by an appropriate molding means such as injection molding using various thermoplastic resins such as polyester resins such as polyethylene terephthalate, polyamide resins such as nylon, and polyolefin resins such as polypropylene. Can be molded.
In the sealing plug of the present invention, the sealing plug body is preferably molded using a polyolefin-based resin having excellent fitting properties.
The resin material used for the sealing plug may further contain an antistatic agent such as a polyoxyethylene alkylamine mixed composition, a glycerin fatty acid ester, and a linear fatty acid saturated monohydric alcohol.

In providing a moisture absorbing function to such a sealing stopper, it is preferable that the surface area of the moisture absorbent is such that the opening area of the opening of the container body is also increased. Thereby, the moisture absorption function given to the sealing plug can be made better. In particular, by increasing the surface area of the hygroscopic agent, it is possible to improve the initial moisture absorption rate, thereby making it possible to exert the hygroscopic function of the hygroscopic agent before the contents absorb moisture. Become.
Moreover, the maximum moisture absorption amount of the hygroscopic agent is determined by the thickness and surface area of the hygroscopic agent, and can be freely changed depending on the application.

  The present invention is described in detail using the following examples. The present invention is not limited to these examples.

(Experiment Method 1)
Using an extrusion sheet forming machine, the resin of the protective layers (surface layers) 60a and 60b is changed so that the thickness of the moisture absorption layer 60c is constant as shown in FIG. 2 and the moisture absorption layer 60c is an intermediate layer, A laminate sheet 60 was formed. The formed laminate sheet 60 was cut into a size of 10 cm × 10 cm (100 cm ² ), stored over time in a 40 ° C.-75% RH environment, and the weight increase over time was measured. The moisture absorption capacity of each sample was compared with the number of days until reaching the saturated moisture absorption amount, that is, the moisture absorption rate. The sheet (thickness 300 μm) of only the moisture absorption layer 60c (thickness polyethylene blended with 50% by weight of zeolite) without the protective layers 60a and 60b reached the saturated moisture absorption amount in 2 days.

Example 1
In the intermediate layer, a laminate having a structure in which low-density polyethylene is mixed with zeolite at 50% by weight in a thickness of 300 μm and a protective layer 60a, 60b on both surfaces of the intermediate layer has a styrenic thermoplastic elastomer of 100 μm each. A sheet 60 was formed. The number of days of reaching the saturated moisture absorption amount of this sheet was 3 days, and the moisture absorption rate was almost the same as that of the sheet having only the moisture absorption layer although a slight decrease was observed.

(Comparative Example 1)
In the intermediate layer, a laminate sheet 60 having a structure in which low-density polyethylene is mixed with 50 wt% zeolite in a thickness of 300 μm and a protective layer 60a, 60b on both sides of the intermediate layer is provided with low-density polyethylene of 100 μm each. Formed. The number of days of reaching the saturated moisture absorption amount of this sheet was 20 days, and a clear decrease in the moisture absorption rate was observed as compared with the sheet having only the moisture absorption layer.

(Example 2)
A laminate sheet 60 was formed in the same manner as in Example 1 except that 100 μm each of thermoplastic elastomers made of a polymer of silicone and low density polyethylene were disposed on the protective layers 60a and 60b on both surfaces of the intermediate layer. The number of days of reaching the saturated moisture absorption amount of this sheet was 3 days, and the moisture absorption rate was almost the same as that of the sheet having only the moisture absorption layer although a slight decrease was observed.

(Experiment Method 2)
Using an injection molding machine, as shown in FIG. 3, a cylindrical hygroscopic material 90 having a constant thickness was embedded in the side wall 70a, and a sealing plug 70 having a protective layer 70b on the innermost surface was formed. The formed sealing plug 70 was stored over time in a 40 ° C.-75% RH environment, and the weight increase over time was measured. The moisture absorption capacity of each sample was compared with the number of days until reaching the saturated moisture absorption amount, that is, the moisture absorption rate. The sealing stopper without the protective layer 70b and the moisture absorbing layer 90 (low density polyethylene blended with zeolite at 50% by weight, thickness 300 μm) exposed on the innermost surface reached the saturated moisture absorption amount in 15 days.

(Comparative Example 2)
The hygroscopic layer 90 was formed by blending zeolite with 50% by weight in low density polyethylene to a thickness of 300 μm, and the innermost protective layer 70b was formed with a sealing plug 70 having a structure in which the low density polyethylene was disposed to a thickness of 100 μm. The number of days to reach the saturated moisture absorption amount of this sealing plug was 60 days, and a clear decrease in the moisture absorption rate was observed as compared with the sealing plug having no protective layer and the moisture absorbing layer exposed on the innermost surface.

(Example 3)
The hygroscopic layer 90 was formed by blending zeolite with 50% by weight in low density polyethylene to a thickness of 300 μm, and the innermost protective layer 70b was formed with a sealing plug 70 having a configuration in which 100 μm of styrene-based thermoplastic elastomer was disposed. The number of days for reaching the saturated moisture absorption amount of this sealing plug is 24 days, there is no protective layer, and although the moisture absorption layer is lower than the sealing plug exposed on the innermost surface, the moisture absorption rate is compared with the configuration of Comparative Example 2. Greatly improved.

Example 4
A sealing plug 70 was formed on the innermost surface protective layer 70b in the same manner as in Example 3 except that 100 μm of a thermoplastic elastomer made of a polymer with silicone was placed on low density polyethylene. The number of days for reaching the saturated moisture absorption amount of this sealing plug is 24 days, there is no protective layer, and although the moisture absorption layer is lower than the sealing plug exposed on the innermost surface, the moisture absorption rate is compared with the configuration of Comparative Example 2. Greatly improved.

(Example 5)
The moisture absorption layer 90 is a low density polyethylene blended with 50% by weight of zeolite and has a thickness of 300 μm. The innermost surface protective layer 80b has a styrenic thermoplastic elastomer of 100 μm, and further the outermost surface protective layer 81 on the side wall of the sealing plug. Also, a sealing plug 80 having a configuration in which 100 μm of a styrene thermoplastic elastomer was disposed was formed. The number of days for reaching the saturated moisture absorption amount of this sealing plug was 18 days, and although there was no protective layer and the moisture absorption layer was slightly lower than the sealing plug exposed on the innermost surface, the moisture absorption rate was almost the same. Compared with the configuration of Comparative Example 2, the moisture absorption rate was significantly improved.

(Example 6)
In the innermost protective layer 80b, 100 μm of a thermoplastic elastomer made of a polymer with silicone is disposed on low density polyethylene, and the outermost protective layer 81 on the side wall of the sealing plug is also made of a heat made of a polymer of silicone with low density polyethylene. A sealing plug 80 was formed in the same manner as in Example 5 except that 100 μm of the plastic elastomer was disposed. The number of days for reaching the saturated moisture absorption amount of this sealing plug was 18 days, and although there was no protective layer and the moisture absorption layer was slightly lower than the sealing plug exposed on the innermost surface, the moisture absorption rate was almost the same. Compared with the configuration of Comparative Example 2, the moisture absorption rate was significantly improved.
Table 1 shows the results of the above-described Examples and Comparative Examples.

  While the present invention has been described with reference to the preferred embodiment, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. Needless to say.

  As described above, the present invention is widely used not only in cases where pharmaceuticals are used as contents, but also in other fields such as foodstuffs, as a technique for storing contents in which deterioration in quality due to moisture absorption is a concern. be able to.

DESCRIPTION OF SYMBOLS 1 Seal plug 10 Laminated body 20 Seal plug 21 Board | substrate 21a Through-hole 22 Side wall part 23 Seal member 40 Container main body 50 Contents 60 Laminated body sheet 60a, 60b Protective layer (surface layer)
60c Hygroscopic layer (intermediate layer)
70, Sealing plug 70a Side wall part 70b Side wall part innermost surface protective layer 80 Sealing plug 80a Side wall part 80b Side wall part innermost surface protective layer 81 Side wall part outermost surface protective layer 90 Moisture absorbing layer

Claims (2)

A substrate having a through-hole, a side wall portion that hangs in a cylindrical shape from the substrate, and a laminate that is held on the inner side surface of the side wall portion,
The laminate is a cylinder composed of a hygroscopic layer and a protective layer, and has a protective layer on the side in contact with the contents,
The moisture absorption layer is made of polyolefin and zeolite ,
The protective layer is made of a thermoplastic elastomer,
The thermoplastic elastomer is a styrenic thermoplastic elastomer,
Or a sealing stopper made of a polymer of polyolefin resin and silicone . The sealing stopper according to claim 1, wherein the laminate has a three-layer structure of a protective layer / a moisture absorbing layer / a protective layer.

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