JP2004268321A - Laminate, its manufacturing method and re-sealable package using the laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a re-sealable package, and a laminate used therein. <P>SOLUTION: A container 100 comprises a film 140 being a lid material and a container main body 120. The container main body 120 is constituted of the laminate 10 obtained by laminating a polyolefin layer 12, a pressure-sensitive adhesive layer 14 and a base material layer 16 in this order. The film 140 is heat-sealed to the polyolefin layer 12 of the laminate 10 at a flange 122. When the film 140 is peeled, the polyolefin layer 12 in the vicinity of a heat-sealed part 30 is broken from the laminate 10 while bonded to the film 140 to form a broken part 40. When the film 140 is bonded to the pressure-sensitive adhesive layer 14 left on the container main body 120 in the broken part 40, the container 100 can be again sealed. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a laminate and a resealable package using the same. In particular, the present invention relates to a package suitably used for food, sundries, pharmaceuticals, and cosmetics.
[0002]
[Prior art]
In the packaging of foods and the like, it is necessary to completely seal the contents put in a container at the time of distribution and storage before use from the viewpoint of preservability of the contents. In use, it is desirable that the container can be easily opened. Furthermore, in a container in which the contents are not used at one time, it is necessary to reseal the container in order to prevent moisture absorption, drying, oxidation and the like.
As an example of such food packaging, a three-layer sheet composed of a high-density polyethylene layer, an adhesive layer, and a polypropylene layer is thermoformed to form a container body, and the top film is formed of the high-density polyethylene of the container body. A container heat-sealed to a layer is disclosed (for example, Patent Document 1). The container has cuts necessary for opening so that the space between the container and the inside of the heat seal portion is opened.
However, making a cut in the heat-sealed portion requires that the interval between the cut and the cut be constant, and a new sealing jig needs to be prepared. There is also a problem that it is difficult to apply to a container having a narrow flange width.
[0003]
Further, a co-extrusion technique of an adhesive in which two kinds of a thermoplastic elastomer and a tackifier are blended is disclosed for the adhesive layer (for example, Patent Document 2). However, the adhesive strength is low and the range of the peel strength is narrow, so that it has been difficult to use it for various applications.
[Patent Document 1]
Japanese Patent Application Laid-Open No. 1-167073 [Patent Document 2]
Japanese Patent Application Laid-Open No. 7-3218
[Problems to be solved by the invention]
An object of the present invention is to provide a resealable package and a laminate used for the package.
[0005]
[Means for Solving the Problems]
According to the first aspect of the present invention, a polyolefin layer, an adhesive layer, and a base layer, which are to be heat-sealed with a film to be bonded, are laminated in this order, and the heat-sealed film is peeled off. Then, the polyolefin layer in the vicinity of the heat seal portion, or the polyolefin layer and the pressure-sensitive adhesive layer, are adhered to the film, and are ruptured from the laminate to form a rupture portion. The remaining adhesive layer provides a laminate that allows the film to adhere to the laminate again.
[0006]
According to a second aspect of the present invention, there is provided a package including the above-described laminate.
According to the third aspect of the present invention, the film to be bonded includes a package body composed of the above-mentioned laminate, and the film is bonded to the package body by being heat-sealed to the polyolefin layer of the laminate. When the film is peeled off, the polyolefin layer in the vicinity of the heat seal portion, or the polyolefin layer and the adhesive layer, are broken while being adhered to the film to form a broken portion, and at the broken portion, the adhesive layer on the film or the package body. Thus, a package that can be resealed by attaching the film and the package body to each other is provided.
According to the fourth aspect of the present invention, the opening / closing member composed of the first film, the second film sealed with the first film to form a packaging space, and made of the above-mentioned laminated body is at least the first member. Attached to the opening of the film, the second film is heat-sealed to the polyolefin layer of the opening and closing member, and when the second film is peeled from the opening and closing member, the polyolefin layer in the vicinity of the heat seal portion, or The polyolefin layer and the pressure-sensitive adhesive layer are broken while adhering to the second film to form a break, and at the break, the first film or the second film is formed by the pressure-sensitive adhesive layer on the first film or the second film. By attaching the film, a resealable package is provided.
[0007]
According to a fifth aspect of the present invention, there is provided the above-mentioned method for producing an adhesive layer, wherein a styrene-based thermoplastic elastomer, a tackifier and a process oil are kneaded and melted, and the process oil is injected from the middle of a single screw extruder. You.
According to a sixth aspect of the present invention, there is provided the above-described method for producing a laminate, wherein the pressure-sensitive adhesive layer and the polyolefin layer are formed by co-extrusion.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described with reference to the drawings.
FIG. 1 shows the relationship between the laminate of the present invention and the film to be bonded.
In the laminate 10 of the present invention, a polyolefin layer 12, an adhesive layer 14, and a base layer 16 are laminated in this order.
The film to be bonded 20 is thermally welded to the polyolefin layer 12 of the laminate 10. That is, the film 20 and the laminate 10 are adhered by the heat seal portion 30.
FIG. 1 shows a state where the film 20 is pulled and peeled off from the laminate 10. As shown in this figure, the polyolefin layer 12 near the edge 32 of the heat seal portion 30 is broken from the laminated body 10 while being adhered to the film 20, and a broken portion 40 is formed. At the break portion 40, the adhesive layer 14 remains in the laminate 10.
By bonding the polyolefin layer 12 adhered to the film 20 to the adhesive layer 14 exposing the break 40, the film 20 can be adhered to the laminate 10 again.
[0009]
FIG. 2 shows the relationship between still another laminate of the present invention and a film to be bonded.
The laminate 50 of the present invention includes a polyolefin layer 12 and an adhesive layer 14, and the polyolefin layer 12, the adhesive layer 14, and the polyolefin layer (base layer) 12 are laminated in this order.
FIG. 2 shows a state where the film 20 is pulled and peeled off from the laminate 50.
As in FIG. 1, the film to be bonded 20 is heat-welded to the polyolefin layer 12 of the laminate 50, but when the film 20 is peeled off, the polyolefin layer 12 near the edge 32 of the heat seal portion 30 is attached to the film 20. The laminated body 50 is broken while being adhered, and the broken portion 40 is formed.
At the break portion 40, the film 20 can be adhered to the laminate 50 again by the adhesive layer 14 remaining on the laminate 50.
[0010]
In these drawings, only the polyolefin layer 12 is broken by bonding to the film 20. However, the polyolefin layer 12 and the adhesive layer 14 may be broken by bonding to the film 20.
The laminates 10 and 50 and the film to be bonded 20 of the present invention can be used for the opening and closing part of a package. At that time, the seal is opened at the heat seal edge portion, and the re-adhesion portion is formed there, so that a general seal machine such as a bag making seal machine, a cup seal machine, an impulse seal machine, etc. can be employed as it is.
Moreover, since the adhesive layers 14 are not exposed, the laminates 10 and 50 of the present invention are easy to handle without being adhered to each other even in a wound state.
[0011]
Next, this laminate will be described in more detail.
The laminate includes a polyolefin layer, an adhesive layer, and a substrate layer, as shown in FIGS.
The polyolefin layer is a polyolefin such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (L-LDPE), random polypropylene (RPP), homopolypropylene (HPP), block polypropylene (BPP), etc. Or a mixture thereof.
[0012]
The adhesive layer preferably comprises a styrene-based thermoplastic elastomer, a tackifier and a process oil.
Examples of the styrene-based thermoplastic elastomer include a styrene-isoprene-styrene block copolymer, a copolymer obtained by hydrogenating a styrene-butadiene-styrene block copolymer, and a styrene-ethylene-styrene block copolymer. And acid-modified products thereof, and styrene-ethylene-propylene-styrene block copolymers. Preferably, it is a hydrogenated product of a styrene-isoprene-styrene block copolymer having a low odor.
Examples of the tackifier include petroleum resins (aliphatic, aromatic, copolymers and alicyclics thereof), hydrogenated petroleum resins, rosin and its derivatives, terpene resins, hydrogenated terpene resins, and the like. No. Preferably, it is an alicyclic saturated hydrocarbon resin. Examples of process oils include paraffinic, naphthenic, aromatic and the like. Preferably, it is a naphthenic process oil.
By using the process oil, the adjustment range of the adhesive strength of the adhesive layer is widened.
The blending amounts of the styrene-based thermoplastic elastomer, the tackifier and the process oil are not limited, but are 15 to 30 parts by weight, 40 to 70 parts by weight and 5 to 35 parts by weight, preferably 20 to 25 parts by weight. , 50-60 parts by weight and 15-25 parts by weight.
The adhesive layer may further include an inorganic filler such as talc and calcium carbonate, a foaming agent, a coloring agent such as titanium oxide, and the like, as long as the properties are not impaired.
[0013]
The base layer is composed of polypropylene (PP), polystyrene (PS), polyethylene (PE), PP / EVOH / PP, PS / EVOH / PS, PE / Ny / PET, L-LDPE / AL / PET, etc. (PET: polyethylene terephthalate, Ny: polyamide, AL: aluminum foil, L-LDPE: linear low-density polyethylene, EVOH: ethylene-vinyl alcohol copolymer).
The base material layer may be constituted not only by one layer but also by laminating a plurality of layers, depending on the use.
[0014]
The thickness of the polyolefin layer is preferably 20 μm or less. Particularly preferred is 5 μm to 15 μm. If the thickness of the polyolefin layer exceeds 20 μm, the opening strength is too high to open.
The thickness of the adhesive layer is usually from 2 μm to 50 μm, but is not limited thereto.
[0015]
The adhesive layer can be produced by kneading and melting a styrene-based thermoplastic elastomer, a tackifier and a process oil. Preferably, the process oil is manufactured by injecting and forming from the middle of a single screw extruder.
If the process oil is formed by being injected in the middle of the single-screw extruder, the cost of the extruder is low, and the adjustment of the adhesive strength becomes easy only by changing the injection amount of the process oil.
The polyolefin layer and the base material layer can be produced by a multilayer coextrusion method or a thermal lamination method.
[0016]
In the laminate, preferably, at least the adhesive layer and the polyolefin layer are formed by co-extrusion.
When formed by co-extrusion, the polyolefin layer can be easily thinned, and the opening strength can be easily adjusted.
The laminate can be specifically manufactured as follows.
{Circle around (1)} The polyolefin layer and the adhesive layer are co-extruded and heat-laminated to the substrate layer.
{Circle around (2)} Coextruding a polyolefin layer, an adhesive layer, and a substrate layer.
{Circle around (3)} The polyolefin layer, the adhesive layer, and the base layer are co-extruded and dry-laminated or extruded with another base film.
The laminate may be used as it is as a bag-making or lid material in a package, or may be thermoformed and used. Alternatively, it may be heat-bonded to the bag while being inserted into a production sealing machine in the form of a tape.
[0017]
Next, the film to be bonded will be described.
The film is made of PET / Ny / CPP, PET / AL / CPP, PET / Ny / L-LDPE, PET / AL / L-LDPE, Ny / L-LDPE, transparent deposited PET / LDPE, Ny / EVOH / LDPE, OPP / CPP including all heat-bondable films (PET: polyethylene terephthalate, Ny: polyamide, CPP: casting polypropylene film, AL: aluminum foil, L-LDPE: linear low density polyethylene, LDPE: low density polyethylene, EVOH: ethylene-vinyl alcohol copolymer, OPP: biaxially oriented polypropylene film).
This film can be manufactured by a usual method.
The thickness of the film is usually from 40 μm to 100 μm, but is not limited to this.
[0018]
The heat-sealing method is not particularly limited, but the heat-sealing can be performed by a bag-making sealing machine, an impulse sealing machine, or the like.
The strength of the heat seal is higher than the adhesive strength between the polyolefin layer and the adhesive layer of the laminate, or higher than the adhesive strength between the base material layer and the adhesive layer.
[0019]
In the laminate of the present invention, a portion having low strength is broken due to the relative relationship between the strength of heat sealing and the bonding strength between the layers.
The adhesive strength of the heat seal depends on the heat sealing conditions such as temperature, pressure and time, the thickness of the polyolefin surface, the resin selection, etc., and the adhesive strength between the polyolefin layer and the adhesive layer depends on the mixing ratio of the adhesive layer and the like. The adhesive strength of the material layer can be adjusted by adjusting the mixing ratio of the pressure-sensitive adhesive layer and the resin of the base material layer.
In particular, in the present invention, since the polypropylene layer or the adhesive layer of the laminate can be made thin by a co-extrusion method, the film can be easily broken at the end of the heat seal when the film is peeled off.
[0020]
The laminate and the film to be bonded of the present invention can be used as a package. The package of the present invention is particularly suitable for food, miscellaneous goods, pharmaceuticals, or cosmetics.
[0021]
Hereinafter, an embodiment of a package will be described with reference to the drawings. In the drawings, the same members are denoted by the same reference numerals, and description thereof will be omitted.
Embodiment 1
FIG. 3 shows a container which is an embodiment of the package of the present invention.
The container 100 includes a container body 120 made of the laminate 10 shown in FIG. 1 and a lid 140 made of a film to be bonded.
The lid member 140 is heat-welded at the flange 122 of the container body 120. That is, the lid member 140 is adhered to the polypropylene layer 12 of the laminate 10 constituting the container body 120 by the heat seal portion 30.
When opening the container 100, the lid 140 is pulled off, and the container 100 is peeled off from the container body 120. FIG. 3 shows the state at this time. As shown in this figure, the polyolefin layer 12 of the heat seal portion 30 is broken from the flange 122 of the container body 120 while being adhered to the lid 140. The adhesive layer 14 is exposed at the break 40 of the flange 122.
The container 100 can be closed again by bonding the polyolefin layer 12 adhered to the lid member 140 to the adhesive layer 14 exposed at the break portion 40 of the flange 122.
[0022]
Embodiment 2
FIGS. 4A and 4B show a bag which is an embodiment of the package of the present invention.
FIG. 4A is a plan view of the bag, and FIG. 4B is a perspective view when the bag is opened.
The bag 200 is composed of a first film 220 and a second film 240. The first film 220 and the second film 240 are sealed at four edges, respectively, to form the bag 200. I have.
In the first film 220, a tape (opening / closing member) 230 made of the laminated body 50 shown in FIG. 2 is heat-sealed to the first film 220 along the length of one side 250 inside the bag 200. ing. The tape 230 forms an opening / closing part.
When the bag 200 is opened, the first film 220 is pulled against the second film 240 in the opening / closing portion, first, the seal portion on the side 250 is opened, and then, the tape 230 is attached to the second film. Peel from 240. At this time, the polypropylene layer (not shown) of the laminate 50 adheres to the second film 240 and peels off, and the adhesive layer 14 of the laminate 50 remains exposed on the first film 220. A break portion 40 is formed on the tape 230 along with the heat seal portion 30.
At this break portion 40, the bag 200 can be closed again by bonding the polyolefin layer adhered to the second film 240 to the adhesive layer 14 exposed on the first film 220.
In this embodiment, the laminated body 50 is taped and attached only to the opening / closing section. However, the entire body or a portion of the first film 220 including the opening / closing section may be laminated, and only the opening / closing section may be heat-sealed.
Further, the shape of the heat seal portion 30 can be changed as appropriate.
Furthermore, although the four sides of the first film 220 and the second film 240 are sealed, the end 250 of the opening portion need not be sealed.
[0023]
【Example】
Example 1
[Manufacture of laminated body]
The laminate shown in FIG. 5 was manufactured using the apparatus shown in FIG.
As shown in FIG. 5, this laminate was composed of a base material layer of 350 μm, an adhesive layer of 30 μm and a polyolefin layer of 10 μm, and the total thickness of the laminate was 390 μm.
The substrate layer was composed of a polypropylene (PP) layer, an adhesive layer, a gas barrier layer, an adhesive layer, and a polypropylene (PP) layer, and the thickness ratio (%) of each layer was as follows.
PP layer / adhesive layer / gas barrier layer / adhesive layer / PP layer = 45/3/4/3/45
[0024]
As shown in FIG. 6, the laminate is co-extruded with the distributor 400 in accordance with the positional relationship of the laminate, with the material of each layer supplied from the extruders 300, 320, 340, 360, and 380, and thereafter. The sheet was formed by a T-die 500 and cooled by a cooling roll 600 to produce a sheet.
These steps are further described below.
Using a single screw extruder 300 having a diameter of 50 mm, a gas barrier material (Kuraray Eval F) forming a gas barrier layer was extruded.
At the same time, using a single screw extruder 320 having a diameter of 50 mm, an adhesive (Mitsui Chemical Admer QF500) forming an adhesive layer was extruded on both sides of the gas barrier material.
Further, using a single screw extruder 340 having a diameter of 65 mm, polypropylene (Idemitsu Polypropylene E-105GM) forming a polypropylene layer is fed to both sides of the two adhesives, and a single screw extruder 360 having a diameter of 50 mm with a dalmage is used. 20 parts by weight of a styrene-based thermoplastic elastomer (Kuraray Sebuton 1001), 55 parts by weight of a hydrogenated petroleum resin (Idemitsu Imarb P-125) as a tackifier, 25 process oil (Idemitsu Kosan Diana Process Oil PW-90) 25 A part by weight and 1 part of a stabilizer (Ciba Specialty Irganox 1010) were kneaded to extrude an adhesive forming the adhesive layer 14.
Specifically, the styrene-based thermoplastic elastomer, the hydrogenated petroleum resin, and the stabilizer were supplied to the hopper 362 of the extruder 360. At the boundary between the measuring section and the kneading section of the extruder 360, a hole having a diameter of 5 mm is formed in the barrel 364, and the process oil is injected into the barrel 364 from here while controlling the flow rate using a pump 366. .
Using a single screw extruder 380 having a diameter of 50 mm, high-density polyethylene (Idemitsu HD110J) forming the polyolefin layer 12 was sent out.
[0025]
The materials supplied from the extruders 300, 320, 340, 360, and 380 are combined by the distributor 400, formed into a sheet by the T-die 500, and cooled by the cooling roll 600 to produce a laminate. did.
[0026]
[Manufacture of containers]
Example 2
From the laminate sheet produced in Example 1, a container body having a diameter of 80 mm, an outer punching diameter of 100 mm, and a capacity of 80 cc was produced by thermoforming. A flange having a width of 10 mm was formed in the container body.
PET / EVOH / L-LDPE (12 μm / 12 μm / 50 μm) was used as the lid material film. A lid material having an outer diameter of 110 mm was heat-sealed to the above-mentioned flange of the container body at a temperature of 185 ° C. for 2 seconds under a pressure of 200 kg / piece.
At this time, the shape of the contact portion of the seal blade with the lid member was a circle having a width of 5 mm, and the outer seal edge had a diameter of 95 mm and the inner seal edge had a diameter of 85 mm so as to seal at the center of the flange of the container body. Was.
When the lid of the container was opened, it could be easily opened. The polyolefin layer of the laminate remained attached to the lid, and the adhesive layer was exposed and remained on the flange of the container body. When the lid was pressed against the flange again, it was easily re-adhered.
At this time, the opening strength at 120 ° peeling was 15 N / 15 mm width, and the opening strength after resealing was 12 N / 15 mm width at the same angle.
[0027]
Example 3
A laminate was manufactured in the same manner as in Example 1 except that the thickness of the polyolefin layer was set to 20 μm.
Using this laminate, a container was produced in the same manner as in Example 2.
When the lid material was opened, the outer seal edge was easily cut, and the lid material was finally opened.
At this time, the opening strength at 120 ° peeling was 25 N / 15 mm width, and the opening strength after resealing was 12 N / 15 mm width at the same angle.
[0028]
Comparative Example 1
A laminate was manufactured in the same manner as in Example 1 except that the thickness of the polyolefin layer was set to 30 μm.
Using this laminate, a container was produced in the same manner as in Example 2.
An attempt was made to open the lid, but the polyolefin layer did not break at the seal edge and could not be opened.
[0029]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the resealable package and the laminated body used for it can be provided.
[Brief description of the drawings]
FIG. 1 is a view showing a relationship between a laminate of the present invention and a film to be bonded.
FIG. 2 is a diagram showing the relationship between another laminate of the present invention and a film to be bonded.
FIG. 3 is a view showing a container which is an embodiment of the package of the present invention.
FIG. 4 is a view showing a bag which is an embodiment of the package of the present invention.
FIG. 5 is a view showing a laminate manufactured in Example 1.
FIG. 6 is a view showing a manufacturing apparatus of a laminate used in Example 1.
[Explanation of symbols]
10,50 laminated body 12 polyolefin layer 14 adhesive layer 16 base layer 20 adhered film 30 heat seal part 40 break part 100 container (package)
120 Container body (package body)
140 Lid (film)
200 bags (package)
220 First film 230 Tape (opening / closing member)
240 Second Film

Claims (11)

A polyolefin layer to be heat-sealed with the film to be bonded, a pressure-sensitive adhesive layer, and a base material layer, which are laminated in this order,
When the heat-sealed film is peeled off, the polyolefin layer near the heat-sealed portion, or the polyolefin layer and the adhesive layer, while being adhered to the film, are broken from the laminate to form a broken portion,
A laminate in which the film can be adhered to the laminate again by the adhesive layer attached to the film or the adhesive layer remaining on the laminate at the break portion. The laminate according to claim 1, wherein the thickness of the polyolefin layer is 20 µm or less. The pressure-sensitive adhesive layer comprises a styrene-based thermoplastic elastomer, a tackifier and a process oil,
The laminate according to claim 1, wherein the adhesive layer and the polyolefin layer are formed by co-extrusion. The laminate according to any one of claims 1 to 3, wherein the adhesive layer is formed by kneading and extruding the process oil in the middle of a single-screw extruder. The laminate according to claim 1, wherein the base material layer is the same as the polyolefin layer. A package comprising the laminate according to claim 1. A film to be adhered, comprising a package body consisting of the laminate according to any one of claims 1 to 5,
The film is adhered to the package body by being heat-sealed to the polyolefin layer of the laminate,
When the film is peeled, the polyolefin layer in the vicinity of the heat seal portion, or the polyolefin layer and the adhesive layer, are broken while being bonded to the film to form a broken portion,
A package that can be resealed by attaching the film and the package body to the film or the package body with an adhesive layer on the film or the package body at the break portion. A first film;
A second film sealed with the first film to form a packaging space;
An opening / closing member comprising the laminate according to any one of claims 1 to 5, which is attached to at least an opening of the first film,
The second film is heat-sealed to a polyolefin layer of the opening / closing member,
When the second film is peeled from the opening / closing member, the polyolefin layer near the heat seal portion, or the polyolefin layer and the adhesive layer, are broken while being bonded to the second film to form a broken portion,
A package that can be resealed by attaching the first film or the second film to the break portion by attaching the first film or the second film to the adhesive layer on the first film or the second film. The package according to any one of claims 6 to 8, which is a package for food, miscellaneous goods, medicine, or cosmetics. The method for producing a pressure-sensitive adhesive layer according to any one of claims 1 to 9, wherein the styrene-based thermoplastic elastomer, a tackifier, and a process oil are kneaded and melted, and the process oil is injected from the middle of a single screw extruder. The method for producing a laminate according to any one of claims 1 to 9, wherein the adhesive layer and the polyolefin layer are formed by co-extrusion.

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