JP5174593B2 - Lid that is welded and pasted by high frequency induction heating - Google Patents

Description

  The present invention relates to a lid member for sealing a container, and more particularly to a lid member provided with a sealant that seals a container by high-frequency induction heating and can be easily peeled off by hand.

  A squeeze container containing a viscous content such as ketchup, salsa sauce or mayonnaise and having a discharge hole such as a round hole or a star hole is well known. The sealing material that seals these discharge holes must be securely affixed to prevent deterioration of quality due to outflow of contents and mixing of outside air, and the strength of the affixing can withstand vibrations at the distribution stage. It must be obtained. On the other hand, when the container is opened, the sealing material for sealing the discharge hole is required to be easily peeled off by hand.

As a lid material provided with such a sealing material that reliably seals the opening of the container and can be easily peeled off by hand at the time of opening, conventionally a sealant for the sealing material that seals the opening side The layers were made of the same material (for example, see Patent Document 1). As an example, if the opening side is made of polypropylene, the sealant sealant layer is also made of polypropylene, and the sealant is provided with a metal layer and welded by high frequency induction heating.
Further, the surface layer of the inner plug in which the discharge hole serving as the opening is formed is made of high-density polyethylene, and the sealant layer of the sealing material is PP / HDPE = 9 / weight ratio of polypropylene (PP) and high-density polyethylene (HDPE). There is also what is made into the mixture used as 1-6 / 4 (for example, refer to patent documents 2). A high density polyethylene of the inner plug and a mixture of polypropylene and high density polyethylene of the sealing material are welded by high frequency induction heating with a metal thin film layer provided on the sealing material.
Japanese Utility Model Laid-Open No. 5-71155, paragraphs 0017 and 0022 JP 2003-212265 A paragraphs 0025, 0026, 0028 Japanese Utility Model Publication No. 56-40682 Table-1

However, if the same polymer material is used for the parts to be welded, the welding strength (adhesion strength) changes with a slight change in the oscillation current during high-frequency induction heating (see, for example, Patent Document 3). Even when a specific polymer material is used for one of the parts to be welded and a mixture containing the same polymer material is used for the other, increasing the same polymer material in the mixture increases the strength of the weld. (See, for example, Patent Document 2), it can be said that it is the same material in the mixture that mainly contributes to the welding, and the strength of the welding is expected to be affected by the change of the oscillation current in the high frequency induction heating. . Note that the change in the oscillation current leads to a change in the magnitude of the high-frequency induction field. A change in the magnitude of the high frequency induction field affects the strength of welding.
In fact, when heat welding is performed using high frequency induction heating means, the position (height) of the high frequency induction coil is adjusted, and heating is performed with the cap placed on the container mouth portion to be sealed and the sealing material to be sealed. I do. However, the distance between the high-frequency induction coil and the sealing material having the metal foil changes due to the change in the height of the container due to the cap, or the shaking of the conveyor that passes under the high-frequency induction coil. The size may change. When the size of the high frequency induction field is insufficient, the adhesion strength of the sealing material is reduced, and there arises a problem that the contents are unexpectedly popped out when the sealing material is dropped in the cap and the consumer removes the cap. Moreover, if the magnitude of the high frequency induction field is too large, there arises a problem that the adhesive strength of the sealing material is too large and the consumer cannot peel off the sealing material by hand.

The present invention provides a lid member that more reliably seals a container and includes a seal member that can be easily peeled off by hand when the container is opened, and a container including the lid member, The purpose is to provide a container with contents.
In addition, even when using high-frequency induction heating means, it is a lid material that is not easily affected by changes in the size of the high-frequency induction field, and seals the container more securely and is more easily peeled off by hand when the container is opened. An object of the present invention is to provide a lid member including a sealing material that can be used.

  In order to solve the above-described problem, the lid according to the first aspect of the present invention is provided at the mouth end 41 of the container body 4 filled with the contents (not shown), for example, as shown in FIGS. A plate-shaped inner plug 2 having a discharge hole 24 through which the contents are passed, which is attached, the inner plug 2 having a layer 21 of high-density polyethylene resin on one surface 21a; and blocking the discharge hole 24 And a propylene-ethylene copolymer having an ethylene content of 2 to 8% by mass on the surface in contact with the one surface 21a of the inner plug 2. And a sealing material 1 having a layer 14 of polymer resin; a propylene-ethylene copolymer within a range where the melting temperature of the propylene-ethylene copolymer resin and the high-density polyethylene resin are the same or the temperature difference is 17 ° C. or less. Resin is higher The sealing material 1 has a metal foil layer 12 on the side opposite to the side in which the propylene-ethylene copolymer resin layer 14 is in contact with the high density polyethylene resin layer 21; the high density polyethylene resin layer No. 21 is characterized in that it is welded and affixed to the layer 14 of the propylene-ethylene copolymer resin using a metal foil as a heat source by high frequency induction heating.

  With this configuration, the propylene-ethylene copolymer resin layer of the sealing material and the high-density polyethylene resin layer of the inner plug are heated by high-frequency induction heating using a metal foil as a heat source, and the propylene-ethylene copolymer resin is heated. And a layer of high-density polyethylene resin can be welded with appropriate adhesion strength. As a result, the problem that the sealing material falls off in the cap and the contents unexpectedly jump out of the discharge hole when the container is opened is alleviated, while the sealing material can be easily peeled off from the inner plug by hand. In addition, in a propylene-ethylene copolymer, when ethylene content rate exceeds 10 mass%, it will become propylene-ethylene copolymer rubber, and it is known that the rigidity and heat resistant property will be inferior. Propylene-ethylene copolymer rubber exceeding 10% by mass is also referred to as EPR. Further, it is known that if it is less than 2% by mass, its impact resistance is inferior. Therefore, in the present invention, a propylene-ethylene copolymer having an ethylene content of 2 to 8% by mass is used as a suitable range.

  Moreover, in the lid | cover material which concerns on the 2nd aspect of this invention, in the lid | cover material 6 which concerns on the said 1st aspect of the said invention, propylene-ethylene copolymer is propylene whose ethylene content rate is 2-8 mass% -An ethylene block copolymer.

  If comprised in this way, an ethylene content rate can be made suitable in a propylene-ethylene block copolymer. The propylene-ethylene block copolymer is usually produced by multistage polymerization, and its ethylene content is usually 2 to 10% by mass for the reason described in paragraph 0007. The propylene-ethylene block copolymer is composed of a crystalline propylene homopolymer portion and a propylene-ethylene random copolymer portion, and the crystalline propylene homopolymer portion is usually 90 to 96% by mass. The propylene-ethylene random copolymer portion is usually 4 to 10% by mass.

  Moreover, in the lid | cover material which concerns on the 3rd aspect of this invention, in the lid | cover material 6 which concerns on the said 1st aspect of the said invention, propylene-ethylene copolymer is propylene whose ethylene content rate is 2-8 mass% -Ethylene random copolymer.

  With this configuration, it becomes easier to heat weld with high density polyethylene than in the case of propylene homopolymer, and the layer of propylene-ethylene copolymer of the sealing material and the layer of high density polyethylene of the inner plug are appropriately welded. To do. If the ethylene content is the same, the propylene-ethylene random copolymer has a lower melting temperature than the propylene-ethylene block copolymer.

In addition, the container according to the fourth aspect of the present invention includes, for example, a container body 4 filled with the contents; the inner plug 2 is attached to the mouth end 41 of the container body 4 as shown in FIG. The lid member 6 (see FIG. 1) according to any one of the first to third aspects of the present invention; the mouth portion 42 of the container main body 4, and the mouth portion 42 that covers the inner plug 2 and the sealing material 1 of the lid member 6. And a cap 3 to be screwed onto the cap.
The container of the present application is a narrow-mouthed container or a wide-mouthed container (indicated as “bottle” or “container” depending on the state of use), and general consumers often refer to the narrow-mouthed container as an English-reading bottle.

  The container with contents according to the fifth aspect of the present invention includes the contents filled in the container body 4; and the container according to the fourth aspect of the present invention.

  According to the present invention, a propellant-ethylene copolymer resin is used as a sealing material that seals the discharge hole by providing the inner plug formed with the discharge hole attached to the mouth end of the container body with a layer of high-density polyethylene resin. Even when both layers are heated and welded by high frequency induction heating, the adhesion strength becomes too high because of the combination of different high molecular weight compounds, high density polyethylene and propylene-ethylene copolymer. Is alleviated. Furthermore, when the ethylene content in the propylene-ethylene copolymer is 2 to 8% by mass, ethylene is appropriately dispersed in the composition of the copolymer. When the melting temperature of the propylene-ethylene copolymer resin of the sealing material is the same as the melting temperature of the high-density polyethylene resin of the inner plug, or the temperature difference is within a range of 17 ° C. or less, the propylene-ethylene copolymer resin is configured higher. Both layers of the resin to be welded are easily heat-welded. As a result, it is possible to obtain a lid material that more reliably seals the container and includes a seal material that can be easily removed by hand when the container is opened.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or corresponding members are denoted by the same or similar reference numerals, and redundant description is omitted. Further, the present invention is not limited to the following embodiments.

FIG. 1 is a diagram showing an embodiment of a lid member 6 according to the present invention. The lid member 6 includes a multilayer inner plug 2 in which a multilayer seal material 1 and a discharge hole 24 are formed. In FIG. 1, the thickness of each layer is exaggerated in the thickness direction in order to show that the sealing material 1 and the inner plug 2 are multi-layered.
FIG. 2 is a view showing a container 7 (see FIG. 4) including the lid member 6 (see FIG. 1). The container 7 includes a container main body 4 that is filled with contents (not shown), an inner plug 2 that is attached to the mouth end 41 of the container main body 4 and has a discharge hole 24 that allows the contents to pass through. A sealing material 1 for sealing the discharge hole 24, a sealing material 1, an inner plug 2, and a cap 3 that covers the mouth portion 42 of the container body 4 and is screwed to the mouth portion 42.

  The content filled in the container body 4 refers to a viscous liquid such as ketchup, salsa sauce or mayonnaise.

Details of the components of the container 7 will be described below.
As shown in FIG. 2, the container body 4 has a mouth portion 42 for filling the contents, and the mouth portion 42 has a screw thread 43 for screwing the cap 3.
The material of the container body 4 is not particularly limited. Moreover, a single layer or a multilayer may be sufficient.
The container body 4 may be any of a direct blow molded product, a stretch blow molded product, an injection molded product, and a cut product from a solidified extruded product. A single layer direct blow molded product, a multilayer direct blow molded product or a multilayer stretch blow molded product is preferable. More preferably, it is a multi-layer direct blow molded container having squeeze properties. The squeeze property means a property that can be easily crushed by hand and the contents can flow out.
The mouth end 41 of the container body 4 is an end of the mouth 42 in an open state, and means a new end obtained by cutting the end of the molded product or the vicinity of the end of the molded product.

As shown in FIG. 2, a discharge hole 24 through which the contents are passed is formed in the inner plug 2 and is attached to the mouth end 41 of the container body 4. The shape of the discharge hole 24 is not particularly limited. For example, any shape such as a star-shaped hole, a circular hole, or a polygonal hole may be used.
The inner plug 2 may be attached in close contact with the mouth end 41 of the container body 4 so that the contents do not flow out and the outside air does not enter.
As shown in FIG. 3, for example, a skirt portion 25 is provided on the entire outer periphery of the inner plug 2, and a protruding portion 26 is formed on the inner periphery of the skirt portion 25, while a groove is formed on the outer periphery of the mouth portion 42 of the container body 4. 44, and the inner plug 2 and the mouth portion 42 are fitted and brought into close contact so that the skirt portion 25 of the inner stopper 2 covers the entire mouth end 41 of the container body 4. Alternatively, the skirt portion 25 may not be provided in the inner plug 2, and the plate-shaped inner plug 2 may be placed on the mouth end 41 of the container body 4 and heat-welded with the mouth end 41. At this time, if the material on the side in contact with the mouth end 41 of the inner plug 2 and the material of the container body 4, and thus the material of the mouth end 41 are the same material, for example, high-density polyethylene resin, it is sufficient when heat-welded. Adhesion strength can be obtained.

As shown in FIG. 1, the inner plug 2 is composed of multiple layers with layers 21 and 23 of high-density polyethylene resin as both surfaces. For example, as shown below, the polyethylene terephthalate layer 22 is configured to be symmetrical in the vertical direction. The symbol “/” represents a laminated interface. The value in () represents the thickness.
A: Layer of high-density polyethylene resin (30 μm) / Both-surface corona-treated polyethylene terephthalate layer (50 μm) / Layer of high-density polyethylene resin (30 μm)
B: High density polyethylene resin layer (30 μm) / Adhesive resin (3 μm) / Polyethylene terephthalate layer (50 μm) / Adhesive resin (3 μm) / High density polyethylene resin layer (30 μm)
C: High-density polyethylene resin layer (30 μm) / Adhesive coating film (1 μm) / Polyethylene terephthalate layer (50 μm) / Adhesive coating film (1 μm) / High-density polyethylene resin layer (30 μm)
A laminated structure of B and C is preferable.
The inner plug 2 only needs to have a high-density polyethylene resin in contact with the sealing material 1, and the laminated structure may not be symmetrical in the vertical direction. It may be a single layer of resin. Moreover, the thickness in () is an illustration, It is not limited to this.

  As the adhesive resin, an ethylene copolymer or an acid graft resin is usually used. In addition, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-methacrylic acid copolymer or its ionomer resin, ethylene- An acrylic acid copolymer, a maleic anhydride graft resin thereof, or a resin composition in which two or more of these are combined and mixed is suitable. Particularly preferred are ethylene-ethyl acrylate copolymers and ethylene-methyl acrylate copolymers. Moreover, the adhesive for dry lamination is suitable for an adhesive coating film. For example, a polyester urethane adhesive, a urethane adhesive, a polyester adhesive, and an acrylic adhesive can be used.

As shown in FIG. 1, the sealing material 1 for sealing the discharge hole 24 of the inner plug 2 is composed of multiple layers. The sealing material 1 has a propylene-based resin layer 14 on the surface in contact with the inner plug 2, and a metal foil layer 12 on the side opposite to the side in contact with the inner plug 2.
The laminated structure of the sealing material 1 is illustrated below. The symbol “/” represents a laminated interface. The value in () represents the thickness.
D: layer formed of cellulose (50 μm) / metal foil layer (20 μm) / both surface corona-treated polyethylene terephthalate layer (50 μm) / propylene-based resin layer (50 μm)
E: layer formed of cellulose (50 μm) / adhesive resin (3 μm) / metal foil layer (20 μm) / adhesive resin (3 μm) / polyethylene terephthalate layer (50 μm) / adhesive resin (3 μm) / Propylene resin layer (50μm)
F: layer formed of cellulose / adhesive resin / boehmite surface-treated metal foil layer (20 μm) / polyethylene terephthalate layer / adhesive resin / propylene resin layer G: layer formed of cellulose / Adhesive coating (1 μm) / metal foil layer / adhesive coating (1 μm) / polyethylene terephthalate layer / adhesive resin / propylene resin layer H: layer formed of cellulose / adhesive coating / Metal foil layer / adhesive coating / polyethylene terephthalate layer / adhesive coating / propylene-based resin layer I: layer formed of cellulose / adhesive coating / metal foil layer / adhesive resin / polyethylene Layer of terephthalate / adhesive resin / layer of propylene resin Preferably, the above-mentioned E and I are laminated.
The sealing material 1 only needs to have at least a propylene-based resin layer 14 and a metal foil layer 12. Moreover, the thickness in () is an illustration, It is not limited to this.

  The propylene-based resin constituting the laminate of the sealing material 1 is a propylene-ethylene copolymer resin mainly composed of propylene, preferably a propylene-ethylene having an ethylene content of 2 to 8% by mass, particularly preferably 3%. Random copolymer resin or propylene-ethylene block copolymer resin. These resins are excellent in film processing for lamination.

The propylene-ethylene block copolymer is mainly composed of propylene, and is composed of a crystalline propylene block that is rigid and an ethylene block or an ethylene unit that destroys the crystallinity. The propylene-ethylene random copolymer has a structure in which propylene is a main component and ethylene units randomly enter the skeleton structure of the crystalline propylene block. Therefore, as compared with the case where a propylene homopolymer is used for the sealant layer of the sealing material 1, it is easy to heat-weld with the layer 21 of the high-density polyethylene resin of the inner plug 2.
If the ethylene content is the same, the propylene-ethylene random copolymer has a lower melting temperature than the propylene-ethylene block copolymer.

The metal foil used for the metal foil layer 12 constituting the laminate of the sealing material 1 is, for example, an aluminum foil or an iron foil, as long as the thickness thereof is about 5 to 200 μm.
The aluminum (Al) foil is a pure aluminum foil or aluminum alloy foil with few pinholes rolled, and JIS-1N30 (99.3 wt% or more Al), JIS-1050 (99.5 wt% or more). Al) and aluminum such as JIS-1100 (Al-0.13 wt% Cu). This aluminum may contain iron, silicon, copper as impurities, titanium, and other inevitable impurities. Moreover, the surface may be protected by boehmite treatment or an organic coating film.

The cellulose referred to in the present invention of the layer 11 formed of the cellulose constituting the laminate of the sealing material 1 is cellulose excluding paper, and refers to a substance that is not melt-processed by itself such as the general names cellophane and rayon. Vinylon can be used in place of cellulose. Preferably, the generic name cellophane is used. Cellophane and vinylon-based films are transparent, so characters and designs printed on metal foil can be seen, and product promotion to consumers is possible.
In addition, since the layer 11 formed of cellulose is the uppermost layer of the sealing material 1, the layer 11 formed of cellulose in contact with the top plate inner surface 31 of the cap 3 is synthesized during high-frequency induction overheating described later. It does not weld to the top plate inner surface 31 of the cap 3 made of resin.

When the sealing material 1 and the inner plug 2 are manufactured, the melting temperature of the propylene-based resin of the sealing material 1 and the melting temperature of the high-density polyethylene resin used for the layer in contact with the sealing material 1 of the inner plug 2 are the same or The propylene resin is made higher in the temperature difference range of 17 ° C. or less. The difference in melting temperature between the two polymer materials is preferably 0 ° C to 17 ° C, and particularly preferably 2 ° C to 12 ° C.
The metal foil layer 12 is disposed on the propylene-ethylene copolymer resin layer 14 side, and the propylene-ethylene copolymer resin close to the metal foil layer 12 is further heated by high-frequency induction heating. Therefore, it is necessary to make the melting temperature of the propylene-ethylene copolymer resin at least the same as the melting temperature of the high-density polyethylene resin or to increase the melting temperature of the propylene-ethylene copolymer resin.
When the difference in melting temperature is brought close to 0 and the melting temperature of the propylene-ethylene copolymer resin is lowered, the propylene-ethylene copolymer resin melts excessively in the course of heating the high-density polyethylene resin layer. As a result, a portion having no propylene-ethylene copolymer resin layer is locally generated, and the adjacent adhesive layer is in direct contact with the polyethylene resin layer of the inner plug. If the sealing material 1 and the inner plug 2 are welded in this state, the adhesion strength at the interface becomes excessively large, which is not practical, which is not preferable. Even when the melting temperature of the propylene-ethylene copolymer resin is increased, if the difference in melting temperature is too large, the propylene-ethylene copolymer resin is insufficiently melted and does not contribute to welding. The inventors have clarified that it is preferable that the melting temperature is at least the same or the difference is about 17 ° C. or less by repeating the experiment.

A method for manufacturing the sealing material 1 and the inner plug 2 will be described. The multilayer sealing material 1 and the multilayer plug 2 are first manufactured as a strip-shaped multilayer film. The band-shaped multilayer film is a band-shaped film or sheet slitted to a predetermined width, and is manufactured as a long product and handled by being wound in a coil shape. Next, the inner plug 2 is formed by punching a long strip-shaped multilayer film into a circle according to the outer diameter of the mouth end 41 of the container body 4. The sealing material 1 is of a size and shape that takes into account the pinch allowance that seals the discharge hole 24 of the inner plug 2 and that is held when peeled from the inner plug 2 by hand. It is formed by punching. The sealing material 1 is preferably the same size as the inner plug 2 or smaller. Then, even when the sealing material 1 is overlapped with the inner plug 2, the cap 3 is easily covered without protruding from the outer periphery of the inner plug 2. The inner plug 2 may have a shape other than a circle.
10-300 micrometers is suitable for the thickness of a strip | belt-shaped multilayer film. When the thickness is 10 μm or more, it is easy to slit into a predetermined width, and when it is 300 μm or less, it is easy to form the sealing material 1 or the inner plug 2 having a smooth surface when punching out from a long strip-shaped multilayer film in a circle.

As shown in FIG. 2, the cap 3 has a thread groove 32 for screwing onto the mouth portion 42 of the container body 4. However, the cap 3 may be attached to the mouth portion 42 by a method other than screwing.
Moreover, the cap 3 should just be a cap which consists of a synthetic resin used normally. For example, density 0.95~0.97g / cm ³ of high density polyethylene (HDPE), medium density polyethylene having a density of 0.91~0.95g / cm ³ (MDPE), density 0.910 to 0. 925 g / cm ³ linear low density polyethylene (LLDPE), very low density linear polyethylene (VLDPE) having a density of 0.86 g or more and less than 0.91 g / cm ³ , density of 0.90 to 0.92 g / cm ³ Low density polyethylene (LDPE), propylene homopolymer or propylene-ethylene copolymer, a propylene-ethylene random copolymer or propylene-ethylene block copolymer having an ethylene content of 1 to 8% by mass , Syndiotactic polypropylene or isotactic polypropylene, ethylene-vinyl acetate copolymer , Ethylene- (meth) acrylic acid which is a copolymer of ethylene and an α, β-unsaturated carboxylic acid or a derivative thereof, or an alkyl ester copolymer thereof or an ionomer thereof, and these comonomers include acrylic acid, Methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, acrylic acid-n-butyl, methacrylic acid-n-butyl, acrylic Examples include cyclohexyl acid, cyclohexyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, glycidyl acrylate, and glycidyl methacrylate. Polyamide resins, polyester resins, and ethylene-cycloolefin copolymers can also be used.
These resins can be used alone or in combination of two or more. A propylene-ethylene random copolymer resin or a propylene-ethylene block copolymer resin having an ethylene content of 1 to 8% by mass, which can withstand repeated fatigue of the cap hinge, is preferable.

  FIG. 4 is a view showing a state in which the cap 3, the sealing material 1, the inner plug 2, and the container body 4 are combined. First, the propylene-based resin layer 14 of the sealing material 1 is an inner plug so that the layer 11 (see FIG. 1) formed of cellulose of the sealing material 1 is in contact with the top plate inner surface 31 (see FIG. 2) of the cap 3. The sealing material 1 and the inner plug 2 are assembled inside the cap 3 so as to be in contact with the layer 21 of the high-density polyethylene resin 2. Next, the cap 3 provided with the sealing material 1 and the inner plug 2 is screwed into the mouth portion 42 of the container body 4 filled with the contents (not shown) in advance. At this time, as shown in FIG. 4, the sealing material 1 and the inner plug 2 are sandwiched between the top plate inner surface 31 of the cap 3 and the mouth end 41 of the container body 4.

  As shown in FIG. 5, the container body 4 covered with the cap 3 is exposed to a high frequency induction field from the outer surface of the top plate of the cap 3. Then, the high density of the propylene-based resin layer 14 and the inner plug 2 of the sealing material 1 due to heat generation of the eddy current loss (that is, high frequency induction heating) generated in the metal foil layer 12 (see FIG. 1) of the sealing material 1. A layer 21 of polyethylene resin is deposited. In the high frequency induction heating, the metal foil layer 12 of the sealing material 1 is preferably maintained at about 300 to 400 ° C. for about 0.5 to 1 second although it is instantaneous.

  The high frequency induction heating means may be any means that generates a conventional high frequency magnetic field. A primary coil that supplies high-frequency power (usually the fixed coil 51) and a secondary coil (not shown) that moves in a high-frequency induction field in synchronization with the container are provided. When the high frequency power is induced to provide a high frequency induction field in the vicinity of the mouth end 41 of the container body 4, the magnitude of the magnetic field can be kept constant.

  The sealing material 1 and the inner plug 2 welded by the high-frequency induction heating means have an adhesion strength of 60 g or more and less than 230 g / 5 mm width, and the sealing material 1 is detached from the inner plug 2 by peeling when the cap 3 is opened. In addition, it was possible to obtain an effect that the sealing material can be easily peeled off by hand. In addition, the determination method of adhesion strength (peeling strength) is T-shaped peeling according to the tensile test method for plastics (JIS: K7113), and details thereof will be described later.

  Below, the specific Example and comparative example of the cover material of this invention are shown. However, the present invention is not limited to the following examples.

Abbreviations of polymer compounds used in Examples and Comparative Examples are shown below. PP (1) to (5) are used for the layer 14 of the propylene-ethylene copolymer resin of the sealing material 1. HDPE (1) is used for the high-density polyethylene resin layer 21 of the inner plug 2.
PP (1): Propylene-ethylene random copolymer, density 0.90 g / cm ³ , ethylene content 6.2 mass%, polydispersity 2.8, melting temperature 134 ° C.
PP (2): propylene-ethylene random copolymer, density 0.91 g / cm ³ , ethylene content 3.3 mass%, polydispersity 4.1, melting temperature 142 ° C.
PP (3): Propylene-ethylene random copolymer, density 0.92 / cm ³ , ethylene content 2.0 mass%, polydispersity 2.5, melting temperature 138 ° C.
PP (4): Propylene-ethylene block copolymer, density 0.92 g / cm ³ , ethylene content 2.0 mass%, polydispersity 9.3, melting temperature 147 ° C.
PP (5): propylene homopolymer, density 0.94 g / cm ³ , melting temperature 153 ° C.
HDPE (1): high density polyethylene, density 0.945 g / cm ³ , melting temperature 130 ° C.
Conditions other than the above were the same.

[Adhesion strength (peel strength)]
In the lid material 6 of the present invention, the adhesion strength (peeling strength) between the sealing material 1 and the inner plug 2 was determined by T-shaped peeling according to a plastic tensile test method (JIS: K7113). The specimen (container) is a container in which the sealing material 1 and the inner plug 2 are inserted into the cap 3 in advance, and the cap 3 is screwed and attached to the mouth portion 42 of the container body 4 and then subjected to high frequency induction heating. It is. The adhesion strength was measured at an ambient temperature of 23 ° C. using an Instron universal testing machine (model: 1122). The adhesion strength is represented by the following symbols.
A: Adhesive strength is 100 g or more and less than 230 g / 5 mm width. In this range, the sealing material 1 can be easily peeled off by hand, and when the cap 3 is opened, the sealing material 1 does not fall off due to peeling off, and the sealing material can be applied even if the container 7 is dropped from a height of 10 cm and an internal pressure is applied. No dropout due to peeling of 1.
If the welding of the sealing material 1 and the inner plug 2 can withstand the internal pressure generated by the impact of dropping even if the container is dropped from a height of 10 cm, the container 7 is used as a product with the container body 4 filled with the contents. It is empirically known that the sealing material 1 maintains a welded state without peeling even when it is circulated.
○: The adhesion strength is 60 g or more and less than 100 g / 5 mm width. In this range, the sealing material 1 can be easily peeled off by hand, and when the cap 3 is opened, the sealing material 1 does not fall off due to peeling (a lower limit level that is practically acceptable).
X: Adhesion strength is 30 g or more and less than 60 g / 5 mm width. In this range, the sealing material 1 can be easily peeled off by hand, but when the cap 3 is opened, there is a dropout due to peeling of the sealing material 1 (there is a problem in practice).
Δ: Adhesion strength is 230 g or more / 5 mm width. In this range, the sealing material 1 cannot often be peeled off by hand (because it is strongly welded, there is a practical problem).

In the following, for example, in Example 1, PP (1) was used as the propylene-ethylene copolymer resin of the sealing material 1, and HDPE (1) was used for the high-density polyethylene resin that is the surface layer of the inner plug 2. Show.
Example 1: PP (1) x HDPE (1)
Example 2: PP (2) x HDPE (1)
Example 4: PP (4) x HDPE (1)
Comparative Example 5: PP (5) × HDPE (1)

  In Example 1, the adhesion strength was judged as ◎. In the container using the lid material of Example 1, the sealing material 1 can be easily peeled off from the inner plug 2 by hand, and the sealing material 1 is peeled off from the inner plug 2 when the cap 3 is opened. Also, even when the container 7 was dropped from a height of 10 cm and an internal pressure was applied, the sealing material 1 was not peeled off from the inner plug 2.

  In Example 2, the determination of the adhesion strength was “good”. In the container using the lid material of Example 2, the sealing material 1 can be easily peeled off from the inner plug 2 by hand, and the sealing material 1 is peeled off from the inner plug 2 when the cap 3 is opened. It never happened.

  In Example 4, the determination of the adhesion strength was “good”. In the container using the lid material of Example 4, the sealing material 1 can be easily peeled off from the inner plug 2 by hand, and the sealing material 1 is peeled off from the inner plug 2 when the cap 3 is opened. It never happened.

  In Comparative Example 5 for comparison with the Examples, the adhesion strength was judged as x. In the container using the lid material of Comparative Example 5, the sealing material 1 could be easily peeled off from the inner plug 2 by hand, but the sealing material 1 was peeled off from the inner plug 2 when the cap 3 was opened. There was.

[Recall]
Even if the cover material satisfies the adhesion strength, it cannot be put into practical use if the reproducibility is small and the uncertainty is large. Here, the reproducibility means that the adhesion strength is measured for every 100 specimens (containers), and the arithmetic average excluding the maximum and minimum values is the same value for the adhesion strength of each specimen and two significant digits. The percentage (%) is shown as an integer value in increments of 5%. If the reproducibility is large, the lid made of the same material has a stable adhesion strength and can prevent product deterioration due to peeling of the sealing material after the product is manufactured (including the distribution stage).

  FIG. 6 is a table showing the recall of the lid member 6 (Examples 1, 3, 4) according to the embodiment of the present invention and the recall of Comparative Examples 1-5. In Comparative Examples 1 to 4, a mixture of polypropylene (melting temperature 165 ° C.) and high-density polyethylene (melting temperature 135 ° C.) was used instead of the propylene-ethylene copolymer resin layer of the sealing material 1, and the inner plug had a high density. A single layer of polyethylene (thickness 110 μm, melting temperature 130 ° C.) is used. In addition, the lid | cover material which uses the mixture of a polypropylene and a high density polyethylene for a sealing material, and uses a high density polyethylene for an inner stopper is an invention disclosed by patent document 2. FIG. Moreover, in order to compare with Comparative Examples 1-5, adhesion strength is represented by unit Newton (N).

In the following, for example, in Example 1, PP (1) was used as the propylene-ethylene copolymer resin of the sealing material 1, and HDPE (1) was used for the high-density polyethylene resin that is the surface layer of the inner plug 2. Show. Further, “PP / HDPE (9: 1)” in Comparative Example 1 indicates that the mixing ratio of polypropylene and high-density polyethylene is 9: 1 by weight.
Example 1: PP (1) x HDPE (1)
Example 3: PP (3) x HDPE (1)
Example 4: PP (4) x HDPE (1)
Comparative Example 1: PP / HDPE (9: 1) × HDPE
Comparative Example 2: PP / HDPE (8: 2) × HDPE
Comparative Example 3: PP / HDPE (7: 3) × HDPE
Comparative Example 4: PP / HDPE (6: 4) × HDPE
Comparative Example 5: PP (5) × HDPE (1)
The thicknesses of the PP (1) and PP (3) to (5) are 30 μm, and the thickness of the inner plug 2 including HDPE (1) is 110 μm. Conditions other than the above were the same.

  In a container provided with a lid material having the conditions of Examples 1, 3, 4 and Comparative Examples 1 to 5, sealing is performed by maintaining a thin metal layer of the sealing material at about 400 ° C. for about 1 second by high frequency induction heating. The material and the inner plug were welded.

  Remove the cap from the resulting container, attach a chuck of a force gauge (manufactured by Nidec Simpo, FGC-5) to one end of the sealing material, and force the tension direction to be 90 degrees from the surface of the sealing material. The sealing material was peeled off by pulling the gauge, and the maximum value of the tensile strength at that time was measured as the adhesion strength (peeling strength) between the sealing material and the inner plug. This measuring method is referred to as T-shaped peeling.

  In the above measurement method, it is known that the adhesion strength is preferably 2.9 to 9.8 N (Patent Document 2, Paragraph 0018). Referring to FIG. 6, Examples 1, 3, 4, and Comparative Examples 1 to 4 all show preferable adhesion strength. However, Examples 1, 3, and 4 show a recall of 90% or more, while Comparative Examples 1 to 4 have a recall of 70% or less. For this reason, it is difficult to produce a lid with stable adhesion strength using a lid made of a mixture of polypropylene and high-density polyethylene for the sealing material and high-density polyethylene for the inner plug. It will be understood that there may be a container in which the adhesion strength of the lid member is too weak or too strong. On the other hand, the cover material according to the embodiment of the present invention has a reproducibility of 90% or more, and thus has a stable adhesion strength, and there is little variation in the adhesion strength of the lid material even in a large volume produced container. I understand. Furthermore, it can be seen from Comparative Example 5 that when a propylene homopolymer is used for the sealing material, the reproducibility is satisfied but the adhesion strength is insufficient.

It is sectional drawing of the sealing material and inner stopper which comprise the cover material which concerns on embodiment of this invention. Note that the thickness of each layer is exaggerated in the thickness direction in order to show that the sealing material and the inner plug are multilayer. The positional relationship of a cap, a sealing material, an inner stopper, and a container main body which comprises the container which concerns on embodiment of this invention is shown, It is sectional drawing about a cap, a sealing material, and an inner stopper. It is a side view of a part. FIG. 3 is a side view (partially sectional view) when the inner plug shown in FIG. 2 is fitted to and closely attached to the mouth end of the container body. It is a side view (partial sectional view) after the assembly of the container shown in FIG. It is a perspective view at the time of heating the mouth part end of the container containing a content in the state which covered the cap by high frequency induction heating. It is a table | surface showing the recall of the cover material (Example 1, 3, 4) which concerns on embodiment of this invention, and the recall of Comparative Examples 1-5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealing material 2 Inner plug 3 Cap 4 Container body 6 Lid material 7 Container 11 Layer formed of cellulose 12 Metal foil layer 13 Polyethylene terephthalate layer 14 Propylene resin layer, propylene-ethylene copolymer resin layer 21a One surface 21 High-density polyethylene resin layer 22 Polyethylene terephthalate layer 23 High-density polyethylene resin layer 24 Discharge hole 25 Skirt portion 26 Projection portion 31 Top plate inner surface 32 Thread groove 41 Port end 42 Port portion 43 Thread 44 Groove 51 Fixed coil

Claims (5)

A plate-shaped inner stopper formed with a discharge hole for allowing the contents to pass through, attached to the mouth end of the container body filled with the contents, and having a layer of high-density polyethylene resin on one surface With a stopper;
It is a plate-shaped sealing material affixed to the one surface of the inner plug so as to block the discharge hole, and the ethylene content is 2 to 8% by mass on the surface in contact with the one surface of the inner plug A sealing material having a layer of a certain propylene-ethylene copolymer resin;
The propylene-ethylene copolymer resin and the high-density polyethylene resin have the same melting temperature or the temperature difference is within a range of 17 ° C. or less, and the propylene-ethylene copolymer resin is configured to be higher;
The sealing material has a metal foil layer on a side opposite to a side where the propylene-ethylene copolymer resin layer is in contact with the high density polyethylene resin layer;
The high-density polyethylene resin layer is welded and pasted to the propylene-ethylene copolymer resin layer by high-frequency induction heating using the metal foil as a heat source;
Lid material. The propylene-ethylene copolymer is a propylene-ethylene block copolymer having an ethylene content of 2 to 8% by mass;
The lid according to claim 1. The propylene-ethylene copolymer is a propylene-ethylene random copolymer having an ethylene content of 2 to 8% by mass;
The lid according to claim 1. A container body filled with the contents;
The lid according to any one of claims 1 to 3, wherein the inner plug is attached to a mouth end of the container body.
A mouth portion of the container main body, and a cap screwed onto the mouth portion, which covers the inner plug of the lid member and the sealing material;
container. Contents to be filled in the container body;
A container according to claim 4;
Container with contents.

Images