KR20130080009A - Multilayer sheet, thermally molded container, and easy-open packaging material - Google Patents

Abstract

The multilayer sheet 20 which forms the thermoforming container of an easy-opening package is a surface layer 27 in which a cover material is fused, and polypropylene resin is 30 mass% or more and 70 mass% or less, and propylene of melting | fusing point 130 degrees C or less- It is assumed that the ethylene random copolymer contains 10% by mass or more and 30% by mass or less, and the low-density polyethylene resin having a melting point of 120 ° C or more contains 20% by mass or more and 40% by mass or less. As the underlayer 26 formed adjacent to the surface layer 27, polypropylene resin whose isotactic pentad fraction is 93 mol% or more as a main component.

Description

MULTILAYER SHEET, THERMALLY MOLDED CONTAINER, AND EASY-OPEN PACKAGING MATERIAL}

The present invention relates to a multilayer sheet, a thermoforming container, and an easy-open package having the thermoforming container.

In recent years, with the improvement of safety awareness about food, the container which is easy to open, the lid | cover material, these containers, and the packaging material which cover the contents which improves the sealing property of the contents and can take out contents are proposed (patent) See Documents 1-5).

What is described in patent document 1 is laminating | stacking the A layer which consists of 50-95 wt% of polyolefin resin, 50-5 wt% of ethylene acrylic acid ester, maleic anhydride copolymer system resin, and B layer which consists of polypropylene resin, The structure using the multilayer sheet which consists of is employ | adopted. The thickness dimension of A-layer is 5-500 micrometers.

The thing of patent document 2 is employ | adopted the structure using the film which has a heat-seal layer which consists of 99-55 weight% of low-density polyethylene, and the low-density polyethylene composition of 1-45 weight% of a propylene polymer.

As described in patent document 3, the cover material of an olefin resin is fusion-sealed to the container which consists of a composite sheet which uses the mixed resin film of an olefin resin and a styrene resin as a 1st layer, and makes a styrene resin sheet a 2nd layer. The configuration to make it adopts.

As for patent document 4, 50-83 mass% of polypropylene, 10-35 weight% of high-density polyethylene whose density is 0.95 g / cm <3> or more, melt flow rate is 10-100 g / 10min, and low density polyethylene are 5 The structure which forms the skin layer of the seal surface of a container using the composition containing -15 weight% and the density of 0.90 g / cm <3> or less ethylene-alpha-olefin copolymer containing 2-10 weight% is employ | adopted.

Patent Document 5 describes a polymer composition of a polypropylene having a melting point of 128 to 140 ° C and a melt flow rate of 2.6 to 3.2 g / 10 minutes, and a thermoplastic elastomer comprising an olefinic thermoplastic elastomer or a styrene thermoplastic elastomer. This configuration is adopted.

Japanese Unexamined Patent Publication No. 2003-231226 Japanese Unexamined Patent Publication No. 2002-241716 Japanese Laid-Open Patent Publication No. 57-107812 Japanese Laid-Open Patent Publication 2005-271972 Japanese Laid-Open Patent Publication 2006-150099

By the way, the seal strength of the container and lid | cover material which provided the seal layer is easy to be influenced by sealing conditions, and a variation in strength is easy to occur.

In the conventional packaging body, when a resin having a low melting point is used as the resin of the surface layer to be coagulated and peeled off as a resin material, when continuously produced using a direct hot plate heating type molding machine, the resin adheres to the hot plate and the production can be continued. There is a risk of missing. Moreover, if the raw material used for a lower surface layer is not selected suitably, it will be easy to penetrate excessively at the time of heat sealing, the stability of seal strength will be lost, and there exists a problem of narrowing the conditions at the time of heat sealing.

It is an object of the present invention to provide a multilayer sheet, a thermoforming container, and an easily openable package in which molding is easy and the sealing performance is stable.

The multilayer sheet described in this invention is a multilayer sheet comprised by laminating | stacking at least 2 or more layers of the surface layer and the subsurface layer formed adjacent to this surface layer, The said surface layer is 30 mass% or more and 70 mass% or less of polypropylene resin. And the propylene-ethylene random copolymer having a melting point of 130 ° C. or less contains 10% by mass or more and 30% by mass or less, and the low-density polyethylene resin having a melting point of 120 ° C. or more contains 20% by mass or more and 40% by mass or less. An isotactic pentad fraction is characterized by having polypropylene resin whose main component is 93 mol% or more.

And in this invention, it is preferable that the said underlayer contains 80 mass% or more of polypropylene whose isotactic pentad fraction is 93 mol% or more.

Moreover, in this invention, when content of the polypropylene with an isotactic pentad fraction 93 mol% or more is less than 80 mass%, it is preferable that the said underlayer contains talc in 0.5 mass% or more and 5 mass% or less.

Moreover, in this invention, it is preferable that the said surface layer is 10 micrometers or more and 150 micrometers or less in thickness dimension.

The thermoforming container according to the present invention is a thermoforming container obtained by thermoforming the multilayer sheet according to the present invention and having an opening. A flange portion extending outwardly is formed at the periphery of the opening. The surface layer is characterized in that the inner surface side of the.

The easily openable package according to the present invention includes the thermoforming container according to the present invention and a lid member which is fused to a flange portion of the thermoforming container to close the opening.

And in this invention, the said lid | cover material has a sealant layer in the surface fused to the said thermoforming container, and the resin pool part by the said sealer layer of the said surface layer, the said subsurface layer, and the said lid | cover material is near the opening side of the said flange part. It is preferable that is formed.

According to the present invention, the surface layer of the above-described composition can prevent the resin from adhering to the heating plate of the direct heating type molding machine, for example, when continuously forming the container, and the molding conditions can be set to be wide and easily. It can be molded. Moreover, since it is set as the above-mentioned composition as the surface layer laminated | stacked adjacent to a surface layer, when the lid | cover material is welded to a container, for example, the problem that the fused jig will become excessively dug out can be prevented, and it is stable welding It can manufacture in a state, can prevent a deviation generate | occur | produces in a seal strength, and can provide a stable seal characteristic.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows schematic structure sealed with the lid | cover material in the easy opening package which concerns on one Embodiment of this invention.
It is a perspective view which shows the state which opened the cover material in the easy opening package of this embodiment.
3 is a partial cross-sectional view of the opening start portion in the easy opening package of the present embodiment.
It is sectional drawing which shows the multilayer sheet which forms the thermoforming container in the easy opening package of this embodiment.
It is a schematic diagram which shows the fusion | melting process of the cover material at the time of manufacturing the easy opening package in this embodiment.
FIG. 6 is a partial cross-sectional view showing a state of the first annular seal plate and the flange portion at the time of fusion in the present embodiment. FIG.
7 is a partially enlarged view of the first annular seal half in the present embodiment.
8 is a cross-sectional view showing a state where the easy opening package of the present embodiment is initially opened.
9 is a cross-sectional view showing a state where the easy opening package of the present embodiment is completely opened.
It is sectional drawing which showed the state where the easy opening package which concerns on other embodiment of this invention was initially opened.
It is sectional drawing which shows the state in which the easy opening package of another embodiment was fully opened.

[Structure of Easy Open Package]

EMBODIMENT OF THE INVENTION Hereinafter, the easily openable package of one Embodiment of this invention is demonstrated with reference to drawings.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows schematic structure sealed with the lid | cover material in the easy opening package of this embodiment. It is a perspective view which shows the state which opened the cover material in the easy opening package of this embodiment. 3 is a partial cross-sectional view of the opening start portion in the easy opening package of the present embodiment. It is sectional drawing which shows the multilayer sheet which forms the thermoforming container in the easy opening package of this embodiment.

As shown in FIG. 1 and FIG. 2, the easy-open package 1 packages various articles regardless of forms such as liquids and solids such as food, medicine, cosmetics and sundries.

This easy opening package 1 is provided with the thermoforming container 2 and the cover material 3.

(Configuration of Thermoforming Container)

The thermoforming container 2 has an accommodating portion 23 which opens an opening 21 in an upper surface to form an accommodating space 22 for accommodating an article not shown therein, and is formed in a substantially rectangular tray shape. have. At the periphery of the opening part 21 of this accommodating part 23, the flange part 24 extended in a flange shape toward the outer side is formed in series.

As shown in FIG. 3, this thermoforming container 2 adjoins the base material layer 25, the subsurface layer 26 laminated | stacked adjacent to this base material layer 25, and this subsurface layer 26 It is a laminated body which has the surface layer 27 of the cohesive fracture laminated | stacked.

And the thermoforming container 2 heat-forms the multilayer sheet 20 with the shape machine, such as a direct hotplate heating type | mold molding machine, in the state which the surface layer 27 faces the inner surface side of the accommodating part 23, for example. It is obtained by. In addition, as a shaping | molding method, it is not limited to a direct heating plate heating system, Various shaping | molding methods can be applied.

Here, the multilayer sheet 20 is a laminated structure by which the base material layer 25, the underlayer 26, and the surface layer 27 are laminated | stacked, as shown in FIG.

The base material layer 25 is a structure in which the first base material layer 25A, the first adhesive layer 25B, the gas barrier layer 25C, the second adhesive layer 25D, and the second base material layer 25E are sequentially stacked.

As the first base material layer 25A and the second base material layer 25E, for example, polypropylene resin, polyethylene resin, polyamide resin, polyethylene terephthalate resin, and the like can be used, but not limited thereto. Do not. The thickness dimension of the 1st base material layer 25A and the 2nd base material layer 25E is 100 micrometers or more and 2000 micrometers or less, Preferably they are 200 micrometers or more and 1000 micrometers or less.

Although unsaturated carboxylic acid or its derivative modified polyolefin resin can be used for the 1st contact bonding layer 25B and the 2nd contact bonding layer 25D, polyvinylidene chloride-type resin may be used, for example.

As the gas barrier layer 25C, materials such as polyamide resin, polyethylene terephthalate resin, ethylene-vinyl alcohol resin, polyvinylidene chloride or the like are preferably used. Among them, ethylene-vinyl alcohol resin is used. It is preferable to use.

And the base material layer 25 may further contain additives, such as a dispersing agent, a pigment, or dye.

Examples of the dispersant include glycerin fatty acid ester monoglycerides, sorbitan fatty acid esters, polyglycerol fatty acid esters, and the like. And when adding a dispersing agent, content of a dispersing agent is 1 mass% or more and 8 mass% or less, Preferably they are 2 mass% or more and 5 mass% or less.

The subsurface layer 26 contains, as a main component, a polypropylene resin having an isotactic pentad fraction of 93 mol% or more, preferably 97 mol% or more. In addition to the polypropylene resin, the lower layer 26 may contain various polyolefin resins, polystyrene resins, polyester resins, mixtures thereof, and the like. As polypropylene resin, homo polypropylene, random polypropylene, etc. are used individually or in combination suitably.

The content of polypropylene resin is 60 mass% or more and 90 mass% or less, Preferably it is 65 mass% or more and 85 mass% or less, More preferably, they are 80 mass% or more and 85 mass% or less. Here, when content of polypropylene resin becomes less than 60 mass%, there exists a possibility that it may generate | occur | produce the problem that excess digging easily arises at the time of sealing. On the other hand, it is because there exists a possibility that the problem that a crack will generate | occur | produce well in the thermoforming container 2 will arise when content of polypropylene resin exceeds 90 mass%.

Moreover, it is preferable that the underlayer 26 contains 80 mass% or more of polypropylene whose isotactic pentad fraction is 93 mol% or more. This is because when the polypropylene is less than 80% by mass, there is a risk of causing a problem that excess digging easily occurs at the time of sealing.

In addition, when the lower layer 26 contains less than 80 mass%, especially 65 mass% or more and less than 80 mass% of polypropylene with an isotactic pentad fraction 93 mol% or more, 0.5 mass% or more and 5 mass% of talc It is preferable to contain below. Here, when talc becomes less than 0.5 mass%, there exists a possibility that the digging stability at the time of sealing may worsen. On the other hand, when talc increases more than 5 mass%, it is necessary to make heating temperature at the time of thermoforming higher, and there exists a possibility that it may adhere to the hotplate of a molding machine.

In addition, similarly to the base material layer 25, the subsurface layer 26 may further contain additives such as a dispersant, a pigment, or a dye.

Moreover, when the isotactic pentad fraction of polypropylene resin becomes smaller than 93 mol%, the underlayer 26 is easy to produce excess at the time of sealing, and is set to 93 mol% or more.

Here, the measurement of the isotactic pentad fraction used as an index of stereoregularity can illustrate the method etc. based on the ¹³ C-NMR method (Macromolecules, 6925, 1973) disclosed by A. Zambelli, for example. have. Specifically, 220 mg of i-PP sample was first collected in a 10 mm diameter NMR sample tube, and 2.5 ml of a 1,2,4-trichlorobenzene / heavy benzene mixed solution (90/10 vol%) was added thereto at 140 ° C. After melt | dissolving a mixture uniformly, ¹³ C-NMR spectrum was measured using JNM-EX400 (brand name: Nihon Electronics Corporation make). ¹³ C-NMR spectrum measurement conditions are shown below.

Pulse width: 7.5 ㎲ / 45 degrees

Observation frequency range: 25,000 Hz

Pulse repetition time: 4 seconds

Measurement temperature: 130 ℃

Number of integrations: 10,000 times

In addition, the isotactic pentad fraction is a total of nine types of binding patterns of propylene 5 molecules ("mmmm", "mmmr", "rmmr", "mmrr", "rmrr + mrmm", "rmrm", "rrrr", "mrrr"). "," Mrrm ") is defined as the relative ratio of the peak area corresponding to" mmmm "with respect to the area of all nine peaks observed as a ¹³ C-NMR spectrum. Specifically, it calculated by the following relational formula (1). Here, when there are two overlaps, a vertical line is drawn vertically from the curved portion of the two peaks to the base line, and both peaks are divided (vertical division method).

{Relationship (1)}

Isotactic pentad fraction (mol%)

 = {A (mmmm) / A (total)} x 100... (One)

Here, A (mmmm) is the area of the mmmm peak, and A (total) means the sum of nine peak areas.

In addition, when two peaks overlap, a method of performing waveform separation as an aggregate of Lorentz-type peaks in addition to the vertical division method is also known, and a value obtained using analysis software (ALICE 2 of Nippon Electronics Co., Ltd.). You can also use

The surface layer 27 is comprised from the resin composition containing polypropylene resin, the propylene ethylene random copolymer of melting | fusing point 130 degrees C or less, and the low density polyethylene-type resin of melting | fusing point 120 degreeC or more.

As polypropylene resin, homo polypropylene, random polypropylene, block polypropylene, etc. are used individually or in combination suitably.

And as a polypropylene resin, melt flow rates are 0.3 g / 10 minutes or more and 0.8 g / 10 minutes or less, Preferably they are 0.4 g / 10 minutes or more and 0.7 g / 10 minutes or less are used. If the melt flow rate is smaller than 0.3 g / 10 min, the surface layer 27 may not spread evenly. On the other hand, it is because there exists a possibility that dispersibility may be impaired when melt flow rate becomes larger than 0.8 g / 10min.

Moreover, content of polypropylene resin is 30 mass% or more and 70 mass% or less, Preferably they are 40 mass% or more and 50 mass% or less. When content of polypropylene resin is less than 30 mass%, adhesiveness with the cover material 3 is weak, and there exists a possibility that adhesiveness may deteriorate or heat resistance may deteriorate. On the other hand, when content of polypropylene resin exceeds 70 mass%, it is because adhesiveness becomes it strong too much and opening property may deteriorate.

Content of the propylene ethylene random copolymer of melting | fusing point 130 degrees C or less is 10 mass% or more and 30 mass% or less, Preferably they are 15 mass% or more and 25 mass% or less.

As the propylene-ethylene random copolymer, a melt flow rate of 0.5 g / 10 min or more and 3 g / 10 min or less, preferably 1.5 g / 10 min or more and 2.5 g / 10 min or less is used. If the melt flow rate is smaller than 0.5 g / 10 min, the surface layer 27 may not spread evenly. On the other hand, it is because there exists a possibility that dispersibility may be impaired when melt flow rate becomes larger than 3 g / 10min.

And as melting | fusing point higher than 130 degreeC as a propylene ethylene random copolymer, there exists a possibility that the sealing property with the cover material 3 may become weak. For this reason, melting | fusing point of a propylene ethylene random copolymer is 130 degrees C or less, Preferably it is 120 degreeC or more and 130 degrees C or less.

Moreover, when content of a propylene ethylene random copolymer becomes less than 10 mass%, there exists a possibility that the sealing property with the cover material 3 may become weak. On the other hand, when content of a propylene ethylene random copolymer exceeds 30 mass%, it is because there exists a possibility that sealing property with the cover material 3 may become too strong.

Content of the low density polyethylene-type resin of 120 degreeC or more of melting | fusing point is 20 mass% or more and 40 mass% or less, Preferably they are 25 mass% or more and 35 mass% or less.

As the low density polyethylene resin, a melt flow rate of 3.5 g / 10 min or more and 6.5 g / 10 min or less, preferably 4 g / 10 min or more and 5 g / 10 min or less is used. If the melt flow rate is smaller than 3.5 g / 10 min, the dispersion state may be inhibited. On the other hand, it is because there exists a possibility that a dispersion state may be inhibited when melt flow rate becomes larger than 6.5 g / 10min.

And as a low-density polyethylene resin, melting | fusing point is lower than 120 degreeC, and there exists a possibility that it may adhere to a heating plate with a direct heating type | mold molding machine. For this reason, melting | fusing point of low density polyethylene-type resin is 120 degreeC or more, Preferably they are 120 degreeC or more and 130 degrees C or less.

Moreover, when content of the low density polyethylene-type resin becomes less than 20 mass%, adhesiveness with the lid | cover 3 is too strong and there exists a possibility that a peelability may deteriorate. On the other hand, when content of the low density polyethylene-type resin increases more than 40 mass%, there exists a possibility that the adhesiveness with the cover material 3 may change large.

Moreover, the surface layer 27 may contain additives, such as a dispersing agent, a pigment, or dye, similarly to the base material layer 25 and the subsurface layer 26. FIG.

The surface layer 27 is preferably formed to have a thickness dimension of 10 µm or more and 150 µm or less, particularly 15 µm or more and 100 µm or less. When the thickness dimension of the surface layer 27 becomes thinner than 10 micrometers, it becomes difficult to control thickness dimension, there exists a possibility that productivity may worsen, and there exists a possibility that the surface layer 27 may be discarded at the time of fusion | melting. On the other hand, when the thickness dimension of the surface layer 27 becomes thicker than 150 micrometers, it is because the surface which agglomerates and breaks is not stable, and there exists a possibility that it may cause an external appearance defect at the time of opening.

And the multilayer sheet 20 is shape | molded by the multilayer extrusion molding method which used T die, for example.

Specifically, each base material layer 25, the underside layer 26, and the surface layer 27 which were pushed out from each extruder were used using the extruder corresponding to the base material layer 25, the underlayer 26, and the surface layer 27. Joining, stacking, and molding are performed on special blocks formed just before entering the T die.

(Configuration of the Cover Material)

As shown in FIG. 3, the lid member 3 includes an outer layer 31 that appears on the outside of the easy-open package 1, and a sealant layer 32 that is fused to the surface layer 27 of the thermoforming container 2. And a laminate having an intermediate layer 33 interposed between these outer layers 31 and the sealant layer 32.

The sealant layer 32 of the lid member 3 fused to the surface layer 27 of the thermoforming container 2 is an opening mode in which the surface layer 27 of the thermoforming container 2 is cohesively broken and peeled off (FIG. 8). Reference). Specifically, as shown in FIG. 1 and FIG. 2, the opening portion 34 of the lid member 3 formed at the four corners of the easy opening package 1 is the flange portion 24 of the thermoforming container 2. By tensioning in the direction away from the arrow (arrow direction in FIG. 2), the surface layer 27 is cohesive-broken and peeled, and the easily openable package 1 is opened.

As the outer layer 31 of the lid | cover material 3, a polyethylene terephthalate (PET) film, a biaxially stretched nylon film (O-Ny), etc. can be used, for example.

It is preferable that the intermediate | middle layer 33 uses polyamide resin, polyethylene terephthalate resin, ethylene-vinyl alcohol resin, polyvinylidene chloride, etc., for example.

As the sealant layer 32, for example, polypropylene resin or polyethylene resin is preferably used.

(Composition of Resin Grower)

And as for the easily openable package 1, as shown in FIG. 3, the lid | cover material 3 is fused to the thermoforming container 2 formed from the multilayer sheet 20 mentioned above, and is shown in FIG. 1 and FIG. The annular seal | sticker part 28 shown is formed. By fusion of the surface layer 27 of the thermoforming container 2 and the sealant layer 32 of the lid 3, the opening 21 of the thermoforming container 2 is sealed, and the easy-open package 1 ), The storage space 22 is in a sealed state.

Here, as shown in FIG. 3, the seal part 28 is formed from the 1st annular seal part 281 formed from the 1st annular seal half 7, and the 2nd annular seal half 7a. Formed of a second annular seal 282.

By fusion | melting of this cover material 3, as shown in FIG. 3, the inner periphery vicinity of the annular 1st annular seal part 281 on the flange part 24 (position of X in FIG. 3). The hump-shaped resin pool part 6 is formed in. As for this resin pool part 6, the sealant layer 32 of the lower and lower layers 26, the surface layer 27, and the lid | cover material 3 of the thermoforming container 2 has the opening part 21 of the thermoforming container 2 Is pushed out toward the edge of the opening.

Specifically, as shown in FIG. 3, the resin pools 6 include the first resin pool 61 of the surface layer 27 of the thermoforming container 2 and the second resin pool 62 of the subsurface layer 26. ) And the third resin pool 63 of the sealant layer 32 of the lid member 3 are formed.

The easy-opening package 1 of the open form in which the surface layer 27 of the thermoforming container 2 is cohesively peeled off has such a high sealing property as a packaging container, as it has such a resin sticking part 6 therein, Ease of opening can be maintained in a favorable state according to the opening form of the aggregation peeling. Furthermore, the easily openable package 1 is easily cut by the resin holding part 6 of the lid member 3 and the flange portion 24 of the thermoforming container 2. Moreover, since the easily openable package 1 differs in the direction to which the stress by internal pressure is applied, and the direction which is easy to open by cohesive failure differ, sealing property will improve. Specifically, the stress of the internal pressure is lower in the hump-shaped first resin pool 61 and the second resin pool 62 than in the inner circumferential edge X of the first annular seal portion 281. It is easy to act on the recessed part (position of Y in FIG. 3), and it is difficult to open depending on the stress of internal pressure, and sealing property improves.

Further, the easy-open package 1 is formed around the entire circumference of the inner circumferential vicinity X of the annular first annular seal portion 281 on the upper surface of the flange portion 24 of the thermoforming container 2. A resin pool 6 is formed. And the outer periphery of the annular 1st annular seal part 281 in the opening start part 34 of the thermoforming container 2 is a flat or near the inner periphery of the 1st annular seal part 281. Only the resin pool smaller than the resin pool 6 in (X) is formed.

From this point, in the part other than the opening start part 34, the inner periphery vicinity X of the 1st annular seal part 281 also in the full periphery of the outer periphery of the annular 1st annular seal part 281. You may form an unshown resin pool part of substantially the same size as the resin pool part 6 in the present invention. By setting it as this structure, it is preferable at the point which is excellent in the high sealing property, the ease of opening, and the opening prevention property of the cover material 3 from other than the opening start part 34.

[Manufacturing method of an easy opening package]

Next, the manufacturing method of an easy opening package is demonstrated with reference to drawings.

FIG. 5: is a schematic diagram which shows the fusion | melting process of the cover material at the time of manufacturing the easy opening package in this embodiment. FIG. 6 is a partial cross-sectional view showing a state of the first annular seal plate and the flange portion at the time of fusion in the present embodiment. FIG. 7 is a partially enlarged view of the first annular seal half in the present embodiment.

In manufacturing the easily openable package 1, in order to fuse the flange portion 24 and the lid member 3 of the thermoformable container 2 to bring the easy open package 1 into a sealed state, the thermoformed container ( The cover member 3 is superimposed on the flange portion 24 of 2). And heat sealing is performed by pressing the 1st annular seal board 7 of a heating state from the upper surface of the lid | cover material 3.

In addition, in order to form the hump-shaped resin pool part 6 in the vicinity of the inner peripheral edge X of the seal part of the opening start part 34 as mentioned above, you may use the following method, for example.

The heat seal of the flange part 24 of the thermoforming container 2 and the cover material 3 superimposes the cover material 3 on the flange part 24 of the thermoforming container 2 as shown in FIG. Thus, the first annular seal plate 7 in a heated state is pressed from the upper portion of the lid member 3 in the direction of the arrow in FIG. 5. By this pressurization, the surface layer 27 shown in the flange part 24 of the thermoforming container 2 and the sealant layer 32 of the lid | cover material 3 are fused.

Here, as for the 1st annular seal board 7 used in order to manufacture the easily opening package 1 of this embodiment, R processing is given in the inner periphery with respect to the upper surface of the flange part 24, It is the 1st annular seal board 7 of the shape made so that the periphery may contact the lid | cover material 3 later than the front-end | tip (tip 73 of FIG. 7) of the 1st annular seal board 7. Specifically, the first annular seal panel 7 has a cross section at the outer circumferential side via the boundary A (which is also the tip 73 of the first annular seal panel 7). An inclined surface portion 71 that becomes an inclined shape and a curved surface portion 72 that is R-processed and whose cross section is curved on the inner circumferential side are formed continuously.

Among these, the inclined surface portion 71 formed on the outer circumferential side of the first annular seal bar 7 is formed from the inner circumference to the outer circumference with respect to the surface of the flange portion 24 as shown in FIG. 7. It is preferable that the angle (theta) to be set is set to 2 degrees or more and 20 degrees or less, especially 3 degrees or more and 15 degrees or less. In addition, the angle of this inclined surface part 71 is set suitably by the width | variety H of the 1st annular seal board 7.

When the angle of this inclined surface portion 71 is smaller than 2 °, even when pressurized at the time of fusion, the resin sticking portion 6 shown in FIG. 3 is likely to be formed in the vicinity of the outer periphery of the seal portion 28, and at the time of opening. There exists a possibility that the resistance of the outer side of the seal part 28 in E will increase, and it will become difficult to open smoothly. On the other hand, when the angle of the inclined surface part 71 exceeds 20 degrees, the periphery of the boundary A will not become smooth but sharp, and the lid | cover material 3 may be cut | disconnected at the time of fusion or opening, and it is easy to open This may be inhibited.

Moreover, it is preferable that the radius of curvature R is about 0.2 Hmm or more and about 0.5 Hmm or less in R process performed in the curved part 72 formed in the inner peripheral side in the 1st annular seal board 7. In addition, the curvature radius R of the curved part 72 is suitably set by the width dimension H of the 1st annular seal board 7, as shown by multiplying this numerical range.

When the radius of curvature R of the curved surface portion 72 is smaller than 0.2 Hmm, the periphery of the boundary A is not smooth and sharp, and there is a fear that the lid 3 or the like may be cut at the time of fusion or opening. On the other hand, when the curvature radius R exceeds 0.5 Hmm, even if it pressurizes at the time of fusion | melting, the resin pool part 6 is well formed in the inner periphery X of the seal part 28 of the flange part 24 well. Because it will not be.

Here, with respect to the first annular seal panel 7, these inclined surface portions 71 and the curved surface portion 72 have a boundary A near the inner side with respect to the cross-sectional width direction of the first annular seal panel 7. It is preferable to form so that it may become (near inner periphery). If the boundary A is inward with respect to the cross-sectional width direction of the first annular seal half 7, the curved portion 72 and the first annular seal half (on the inner circumferential side of the first annular seal half 7) The inclined surface portion 71 is also formed on the outer circumferential side of 7), so that the tip 73 comes into contact with the lid 3 before the outer circumferential side of the first annular seal plate 7 during welding. . That is, it is reliably made that the outer periphery of the 1st annular seal board 7 comes into contact with the lid member 3 later than the tip 73. For this reason, the resin pool part 6 is selectively formed inward with respect to the opening part 21 side of the inner peripheral side which contacted previously.

Moreover, in this embodiment, R process is carried out around the inner periphery and outer periphery of the 1st annular seal board 7 corresponding to the site | part other than the opening start part 34 of the thermoforming container 2, A curved surface portion 72 having a curved cross section is formed. And the site | part of the 1st annular seal board 7 corresponding to the opening start part 34 of the thermoforming container 2 is R-processed by the inner periphery, and the curved surface part 72 whose cross section is curved is formed. . For this reason, by using the 1st annular seal board 7 which has a shape which the outer periphery is made to contact the cover material 3 later than the front end 73 of the 1st annular seal board 7, high sealing property, It is preferable at the point which can manufacture the easy opening package 1 excellent in the easy opening property and the opening prevention property of the lid | cover material 3 from other than the opening start part 34.

In addition, in order that the 1st annular seal board 7 may integrally form the seal | sticker part 28 on the main shown in FIG. 1 and FIG. 2, the said inclined surface part 71 and the curved part 72 are ) May be a cyclic seal half (seal ring) formed continuously in a ring shape. Moreover, the ring which provided the said inclined surface part 71 and the curved surface part 72 only about the site | part corresponding to the opening start part 34 of the easy opening package 1 in the 1st annular sealing board 7. It is good also as a type sealing board (sealing).

In order to fuse the flange part 24 and the lid | cover material 3 of the thermoforming container 2 using the 1st annular seal board 7 of the shape shown to FIG. 6 and FIG. 7, as shown in FIG. First, the tip 73 corresponding to the boundary A between the inclined surface portion 71 and the curved surface portion 72 in the first annular seal plate 7 is in contact with the lid member 3. Thereafter, the curved surface portion 72 formed on the inner circumferential side of the boundary A faces the inside of the lid member 3, and the inclined surface portion 71 formed on the outer circumferential side of the boundary A is the lid member. It is pressed toward the outside of (3).

For this reason, the resin component of the surface layer 27 of the thermoforming container 2 and the subsurface layer 26 which adjoins the said surface layer 27 is inside of the thermoforming container 2 from the lower part of said boundary A. In the vicinity of the position where the inner circumferential edge of the first annular seal bar 7 in the flange portion 24 abuts, that is, the inner circumferential edge X of the seal portion 28 of the thermoforming container 2. Bulge-shaped resin pools 61 and 62 are formed. In addition, the flange portion 24 of the thermoforming container 2 is formed in a state where the sealant layer 32 of the lid member 3 is also followed to form the resin pool 63, and they form the resin pool 6. The surface layer 27 shown in the figure and the sealant layer 32 of the lid | cover material 3 are fused.

Here, as fusion conditions, what is necessary is just to determine suitably as fusion temperature according to the kind of material to be fused, etc., What is necessary is just to be 160 degreeC or more and 240 degrees C or less.

Similarly, the fusion pressure may be about 10 kg / cm 2 (100 to 500 kPa) or more and about 50 kg / cm 2 (100 to 500 kPa) or less.

Moreover, only by fusion by the 1st annular seal board 7, there exists a possibility that a foreign matter may enter easily from the outer peripheral edge side. In order to prevent such a thing, the sealant layer 32 of the lid | cover material 3 is made into the flange part (1), forming the above-mentioned hump-shaped resin pool part 6 by the 1st annular seal board 7. After fusion | melting to the surface layer 27 of 24, the surface layer 27 of the thermoforming container 2 was pressurized using the 2nd annular seal board 7a to contact the outer peripheral side of the seal part 28. And the sealant layer 32 of the lid member 3 may be fused together.

If the sealing surface of the said 2nd annular seal board 7a is a smooth flat shape or R shape, it is not necessary to consider the positional relationship of the resin pool 6 and the 2nd annular seal board 7a.

However, in the case where the seal surface of the second annular seal plate 7a is processed so as to allow partial adhesion such as a lottery, the appearance of the opening is damaged by the lump-shaped resin pool 6 being crushed into an uneven shape. Since it may become, it is preferable not to make the 2nd annular seal board 7a contact with the resin pool part 6.

[Opening method of easy opening package]

Next, the opening method of the said easy opening package 1 is demonstrated with reference to drawings.

8 is a cross-sectional view showing a state where the easy opening package of the present embodiment is initially opened. 9 is a cross-sectional view showing a state where the easy opening package of the present embodiment is completely opened.

In addition, the "initial state opened" here refers to the state in which the peeling surface in which the aggregation peeled off did not reach to the resin pool part 6.

In order to open the easy opening package 1 of this embodiment from the opening start part 34, as shown in FIG. 8, when the force F is applied with respect to the cover material 3 in the arrow direction of FIG. And cohesive peeling of the surface layer 27 of the thermoforming container 2 advances.

Moreover, in the place where this aggregation peeling reached the resin pool part 6, the aggregation peeling of the surface layer 27 makes the shape of the resin pool 62 formed in the subsurface layer 26 adjacent to the said surface layer 27. Will follow along.

And when the cohesive peeling of the surface layer 27 reaches to the inner periphery vicinity X of the seal part 28, it will follow the shape of the resin pool 63 formed in the sealant layer 32 of the cover material 3 so that it may follow. Thus, the resin pool 61 of the surface layer 27 of the thermoforming container 2 is cut, so that the thermoforming container 2 and the lid 3 in the easy opening package 1 are easily opened. Will be done.

[Effects of Embodiments]

As mentioned above, according to the said embodiment, the effect shown below is obtained.

That is, in this embodiment, the multilayer sheet 20 which forms the thermoforming container 2 of the easy opening package 1 has 30 mass% or more and 70 mass% or less of polypropylene resin as surface layer 27, and It is assumed that the propylene-ethylene random copolymer having a melting point of 130 ° C or less contains 10% by mass or more and 30% by mass or less, and the low density polyethylene resin having a melting point of 120 ° C or more contains 20% by mass or more and 40% by mass or less. For this reason, the melting start temperature at the time of fusing the lid | cover material 3 to the thermoforming container 2 is set to 120 degreeC or more and about 130 degrees C or less, and can set fusion temperature to about 160 degreeC or more and 240 degrees C or less. For this reason, when manufacturing the thermoforming container 2 using the direct hot plate heating type | mold molding machine effective in continuous production, fusion | melting temperature can be set to a high temperature and wide temperature range compared with the conventional material. Therefore, the thermoforming container 2 can be manufactured efficiently, without causing the problem that the surface layer 27 of the multilayer sheet 20 adheres to the hotplate of a molding machine.

Moreover, as the underlayer 26 formed adjacent to this surface layer 27, it is assumed that polypropylene resin whose isotactic pentad fraction is 93 mol% or more as a main component. For this reason, the rigidity of the subsurface layer 26 improves and when the lid | cover material 3 is fused to the thermoforming container 2, the subsurface layer 26 at the time of pressing the 1st annular seal half 7 tightly. Excess flow can be prevented, and the fluidity of the surface layer 27 can be stabilized. For this reason, a stable seal strength can be obtained and the stable sealing property can be provided, without causing the problem that the 1st annular seal board 7 becomes excessive in the case of fusion | melting. In addition, since excessive flow of the underlayer 26 can be prevented, stable good resin pools 6 can be formed, stable sealing property can also be obtained, and stable sealing property can be provided.

And in this embodiment, the polypropylene of the isotactic pentad fraction 93 mol% contained in the underlayer 26 is 80 mass% or more.

For this reason, it is possible to prevent excessive digging at the time of sealing and to seal satisfactorily.

Moreover, when the polypropylene of the isotactic pentad fraction 93 mol% contained in the underlayer 26 is less than 80 mass%, especially 65 mass% or more and less than 80 mass%, talc is 0.5 mass% or more and 5 mass% It contains below.

For this reason, the rigidity of the lower surface layer 26 can be improved, and the thermoforming container 2 can be made rigid.

Moreover, in this embodiment, the thickness dimension of the surface layer 27 of the multilayer sheet 20 is 10 micrometers or more and 150 micrometers or less.

For this reason, the surface layer 27 of stable thickness can be formed, a yield can be improved, and it can be sealed satisfactorily without being rejected at the time of fusion | melting. In addition, the surface to be agglomerated and broken can be stabilized, and it can prevent that the open appearance is damaged.

And in this embodiment, the thermoforming container 2 which has the flange part 24 extended outward at the periphery of the opening part 21, the surface layer 27 is located in an inner surface side, ie, the accommodating part 23 Is formed by thermoforming the multilayer sheet 20 in a state where the surface layer 27 faces the inner surface side of the sheet.

For this reason, what is necessary is just to fuse and seal the lid | cover material 3 to the flange part 24, and the ease of opening and the opening feeling of the easy opening package 1 are stabilized, and heat resistance and the appearance of a sealing surface become favorable.

In addition, in this embodiment, the sealant layer 32 of the lid | cover material 3 is fused to the flange part 24 in the easy opening package 1, and the opening part 21 side of the flange part 24 is fused. The resin pool part 6 is formed in the vicinity.

 For this reason, when agglomeration peeling advances to the place where the resin pool part 6 is interposed, the stress which peels by the interposition of the resin pool part 6 separates the cover material 3 from the thermoforming container 2 Will act as. For this reason, the cutting | disconnection of the cover part 3 and the flange part 24 of the thermoforming container 2 is favorable, and the easily openable package 1 provided with favorable opening property can be provided. In addition, since the sealant layer 32 of the subsurface layer 26 and the lid | cover material 3 which are hard to coagulate | rupture exist in both surfaces of the surface layer 27 to coagulate-break, sealing property can be improved.

[Modifications]

In addition, the aspect demonstrated above showed one aspect of this invention, This invention is not limited to said embodiment, It is equipped with the structure of this invention, The deformation | transformation within the range which can achieve an objective and an effect, It goes without saying that the improvement is included in the content of the present invention. In addition, the specific structure, shape, etc. in implementing this invention include what was deformed or improved as another structure, a shape, etc. within the range which can achieve the objective and effect of this invention.

That is, although the structure provided with the surface layer 27, the underlayer 26, and the base material layer 25 was shown in the multilayer sheet 20 and the thermoforming container 2 of this embodiment, it is not limited to this.

For example, you may be comprised from two layers, the surface layer 27 and the underlayer 26, without forming the base material layer 25. FIG. In short, it is good also as a structure which makes the subsurface layer 26 function as a base material layer.

Moreover, the base material layer 25 of the multilayer sheet 20 and the thermoforming container 2 of this embodiment is the 1st base material layer 25A, the 1st contact bonding layer 25B, the gas barrier layer 25C, and the 2nd Although the structure provided with the contact bonding layer 25D and the 2nd base material layer 25E was shown, it is not limited to this.

For example, the base material layer 25 may be composed of only the first base material layer 25A.

As mentioned above, the multilayer sheet 20 and the thermoforming container 2 should just be a multilayer structure of two or more layers in which the surface layer 27 and the subsurface layer 26 were included at least.

And although the aspect which the surface layer 27 of the thermoforming container 2 coagulated and peeled off was shown in this embodiment, it is good also as an aspect which the cover material 3 side coagulates and peels off, for example. That is, you may form the cover material 3 from the multilayer sheet of this invention.

Specifically, the sealant layer 32 of the lid member 3 is made of the same material as the surface layer 27 of the multilayer sheet 20, and the underlayer of the multilayer sheet 20 is used as the intermediate layer 33 of the lid member 3. It is set as the same material as (26). 10 and 11, the sealant layer 32 of the lid 3 may be fused to the flange portion 24 of the thermoforming container 2. According to the structure shown in this FIG. 10 and FIG. 11, the sealant layer 32 of the lid | cover material 3 coagulates and peels at the time of opening of the thermoforming container 2 and the lid | cover material 3.

In addition, at the time of opening, both layers of the surface layer 27 of the thermoforming container 2 and the sealant layer 32 of the cover material 3 may be cohesive-broken and opened.

In addition to this, in addition to the easy-opening package 1 consisting of the thermoforming container 2 and the lid member 3 described above, the multilayer sheet of the present invention may be applied to a package of various shapes.

In addition, in manufacturing the easily openable package 1, the first annular seal panel is formed in addition to the resin stud portion 6 formed at a portion corresponding to the position where the inner circumference of the first annular seal panel 7 is in contact. A resin pool may be formed at a portion corresponding to the position at which the outer circumferential edge of (7) contacts.

In this case, since the resin pool portion 6 formed on the inner circumference becomes larger than the resin pool formed on the outer circumference, good ease of opening and high sealability are maintained.

And although the structure which makes talc contain 0.5 mass% or more and 5 mass% or less as the multilayer sheet 20 was illustrated, it is not necessary to contain talc.

In addition, as the multilayer sheet 20, the thickness dimension of the surface layer 27 does not need to be 10 micrometers or more and 150 micrometers or less. Thickness dimension can be set suitably according to a use.

Example

Next, an Example and a comparative example are given and this invention is demonstrated in detail.

In addition, this invention is not restrained at all by the description content of these Examples.

[Packaging]

(Multilayer sheet)

The multilayer sheet consists of a surface layer / 1st base material layer / 1st adhesion layer / gas barrier layer / 2nd adhesion layer / 2nd base material layer described below using the distributor type coextrusion multilayer sheet manufacturing apparatus generally used. A multilayer sheet was prepared.

Surface layer: Setting suitably for each Example and comparative example mentioned later

1st base material layer (subsurface layer), 2nd base material layer: Setting suitably for every Example and comparative example mentioned later

1st contact bonding layer, 2nd contact bonding layer: adhesive resin (maleic anhydride modified PP by Mitsubishi Chemical Corporation (brand name: modic AP P604V))

Gas barrier layer ： Ethylene-vinyl alcohol copolymer resin (manufactured by Kuraray (trade name: Eval J171B))

Thermoforming Container

Using this multilayer sheet, the thermoforming container was formed by heat-molding three times with 200 degreeC and 2.0 second of upper and lower hotplates using the direct hotplate heating type | mold machine (Shinwa Machinery Co., Ltd. (brand name: direct-heated container molding machine)). .

(Cover material)

It molded into the laminated body of three layers of an outer layer / intermediate | middle layer / sealant layer described below.

Outer layer ： Polyethylene terephthalate (Mitsubishi Chemical Corporation make (brand name: deck barry)) 12 micrometers

Intermediate layer ： Nylon (manufactured by Idemitsu Unitec Co., Ltd. (trade name: Uniron S)) 15 μm

Sealant layer: LLPE (manufactured by Idemitsu Unitec Co., Ltd. (trade name: Uniron LS700C)) 60 μm, or polypropylene (PP) (manufactured by Idemitsu Unitec Co., Ltd. (trade name: RT610C)) 60 μm

(Top seal)

The shape of the flange of the formed thermoforming container was suitably formed using a ring-shaped seal half, a convex seal half, an R seal half, and a special shaped seal half, in a flat or convex shape, as will be described later. In addition, the used seal half is as follows.

Examples 1-7 and the ring-shaped seal half of each comparative example are 1.5 mm in width, and the tip shape is flat. Fusion temperature is 190 degreeC, fusion pressure is 150 kg / piece, and fusion time is 1.0 second.

 The convex seal half of Example 8 is 3.0 mm in width, and the tip shape is flat. Fusion temperature is 190 degreeC, fusion pressure is 150 kg / piece, and fusion time is 1.0 second.

The R seal half of Example 9 has a curved surface with a width of 1.5 mm and a radius of curvature of the tip protruding from the center in the width direction of 1.0 mm. Fusion temperature is 210 degreeC, welding pressure is 200 kg / piece, and welding time is 1.0 second.

The special shape of the seal half of Example 10 is 1.5 mm in width, the inclination-angle (theta) is 9 degrees, and curved surface radius is 0.5 mm in the same shape as the 1st annular seal disc 7. Fusion temperature is 210 degreeC, welding pressure is 200 kg / piece, and welding time is 1.0 second.

Example 1

In Example 1, as shown in the following Table 1, the surface layer and the 1st base material layer were formed with the following resin formulation.

Surface layer (thickness 50 micrometers):

40 mass% of polypropylene (PP) (made by Prime Polymer, Inc. (brand name: E105GM))

+ Metallocene system PP (made by Nippon Polypro Co., Ltd. (brand name: WFX6 melting point 128 degrees Celsius)) 30 mass%

+ Low Density Polyethylene (LDPE) (manufactured by Tosso-Nickemi Co., Ltd. (trade name: LW01 melting point 128 ° C)) 30 mass%

First base material layer ：

Polypropylene (PP) (made by Prime Polymer Co., Ltd. (brand name: V300SVE stereoregularity ii97 mol%)) 81.5 mass%

+ Low density polyethylene (LDPE) (made by Nippon Polyethylene Co., Ltd. (brand name: HE30)) 13.5 mass%

+ High density polyethylene (HDPE) (made by Prime Polymer Co., Ltd. (brand name: 6203B)) 5 mass%

As mentioned above, the flange portion was formed flat using a ring-shaped seal half.

(Example 1-1)

In Example 1-1, the sealant layer of the lid | cover material was formed from polypropylene (PP) mentioned above using the multilayer sheet of the said Example 1 using the multilayer sheet of the said Example 1.

(Example 1-2)

In Example 1-2, the sealant layer of the lid | cover material was formed of LLPE mentioned above using the multilayer sheet of the said Example 1 using the multilayer sheet of the said Example 1.

[Example 2]

As Example 2 shows in the following Table 1, the surface layer was formed in the same thickness as Example 1 with the same thickness dimension, and the 1st base material layer was formed with the following resin formulation.

First base material layer ：

68 mass% of polypropylene (PP) (made by Prime Polymer, Inc. (brand name: V300SVE stereoregularity ii97 mol%))

+ High density polyethylene (HDPE) (made by Prime Polymer Co., Ltd. (brand name: 6203B)) 14 mass%

+ Thermoplastic elastomer (manufactured by Tokyo Material, Inc. (trade name: Engage 8200)) 15 mass%

+ Talc (manufactured by Idemitsu Lion Composite Co., Ltd. (trade name: HMP460-1)) 3 mass%

As mentioned above, the flange portion was formed flat using a ring-shaped seal half. Other than that was carried out similarly to Example 1.

[Example 3]

As Example 3 shows in the following Table 1, the surface layer was formed with the following resin formulation, and the 1st base material layer was formed with the same formulation as Example 1.

Surface layer ：

50% by mass of polypropylene (PP) (same material as Example 1)

+ 20 mass% of metallocene-based PP (the same material as Example 1)

+ Low density polyethylene (LDPE) (Example 1 and the same material) 30 mass%

As mentioned above, the flange portion was formed flat using a ring-shaped seal half. Other than that was carried out similarly to Example 1.

Example 4

In Example 4, as shown in the following Table 1, the surface layer was formed with the following resin formulation, and the 1st base material layer was formed with the same formulation as Example 1.

Surface layer ：

Polypropylene (PP) (Same Material as Example 1) 30 mass%

+ 30 mass% of metallocene-based PP (the same material as Example 1)

+ Low density polyethylene (LDPE) (Example 1 and the same material) 40 mass%

As mentioned above, the flange portion was formed flat using a ring-shaped seal half. Other than that was carried out similarly to Example 1.

[Example 5]

As Example 5 shows in the following Table 1, the surface layer was formed with the following resin formulation, and the 1st base material layer was formed with the same formulation as Example 1.

Surface layer ：

Polypropylene (PP) (same material as Example 1) 70 mass%

+ 10 mass% of metallocene-based PP (the same material as Example 1)

+ 20% by mass of low density polyethylene (LDPE) (same material as Example 1)

As mentioned above, the flange portion was formed flat using a ring-shaped seal half. Other than that was carried out similarly to Example 1.

※ 1: Although peeling strength is slightly weak, it is favorable

* 2: When forming a container, it is tensioned on the hot plate but is not attached. Peel strength is slightly strong but good

※ 3: At the time of container shaping, tension is attached to hotplate but is not attached and is good

[Example 6]

In Example 6, as shown in Table 2 below, both the surface layer and the first base material layer were the same as Example 1, and the thickness of the surface layer was formed to be 150 µm.

As mentioned above, the flange portion was formed flat using a ring-shaped seal half. Other than that was carried out similarly to Example 1.

[Example 7]

In Example 7, as shown in Table 2 below, both the surface layer and the first base material layer were the same as in Example 1, and the thickness of the surface layer was formed to be 10 m.

As mentioned above, the flange portion was formed flat using a ring-shaped seal half. Other than that was carried out similarly to Example 1.

[Example 8]

In Example 8, as shown in the following Table 2, both the surface layer and the 1st base material layer were mix | blended with Example 1, and the thickness dimension of the surface layer was formed in 50 micrometers.

As described above, the flange portion was formed into a convex cross section using a convex seal half. Other than that was carried out similarly to Example 1.

[Example 9]

In Example 9, as shown in Table 2 below, both the surface layer and the first base material layer were the same as in Example 1, and the thickness of the surface layer was also formed in the same manner as 50 µm.

As described above, the flange portion was formed flat using an R seal half. Other than that was carried out similarly to Example 1.

[Example 10]

In Example 10, as shown in Table 2 below, both the surface layer and the first base material layer were the same as in Example 1, and the thickness of the surface layer was also formed to be 50 µm.

As mentioned above, the flange part was formed in flat using the sealing board of special shape. Other than that was carried out similarly to Example 1.

※ 1: Although peeling strength is slightly weak, it is favorable

[Example 11]

Example 11 was formed by the same formulation as Example 1, as shown in Table 3 below. The surface layer was formed to a thickness of 160 μm.

[Example 12]

Example 12 was formed by the same formulation as Example 1, as shown in Table 3 below. The surface layer was formed to a thickness of 5 mu m.

[Example 13]

In Example 13, as shown in Table 3 below, the surface layer was formed in the same manner as in Example 1 with a thickness of 50 μm. The first base material layer was formed by the following resin formulation. In addition, it formed similarly to Example 1.

First base material layer ：

75 mass% of polypropylene (PP) (made by Prime Polymer, Inc. (brand name: V300SVE stereoregularity ii97 mol%))

+ High density polyethylene (HDPE) (made by Prime Polymer Co., Ltd. (brand name: 6203B)) 20 mass%

+ Thermoplastic elastomer (manufactured by Tokyo Material, Inc. (trade name: Engage 8200)) 5% by mass

[Example 14]

In Example 14, as shown in Table 3 below, the surface layer was formed in the same manner as in Example 1 with a thickness of 50 μm. The first base material layer was formed by the following resin formulation. In addition, it formed similarly to Example 1.

First base material layer ：

75 mass% of polypropylene (PP) (made by Prime Polymer, Inc. (brand name: V300SVE stereoregularity ii97 mol%))

+ High density polyethylene (HDPE) (made by Prime Polymer Co., Ltd. (brand name: 6203B)) 10 mass%

+ Thermoplastic elastomer (manufactured by Tokyo Material, Inc. (trade name: Engage 8200)) 5% by mass

+ Talc (manufactured by Idemitsu Lion Composite Co., Ltd. (trade name: HMP460-1)) 10 mass%

[Example 15]

In Example 15, as shown in Table 3 below, the surface layer was formed in the same manner as in Example 1 with a thickness of 50 μm. The first base material layer was formed by the following resin formulation. In addition, it formed similarly to Example 1.

First base material layer ：

75 mass% of polypropylene (PP) (made by Prime Polymer, Inc. (brand name: V300SVE stereoregularity ii97 mol%))

+ High density polyethylene (HDPE) (made by Prime Polymer Co., Ltd. (brand name: 6203B)) 20 mass%

+ Thermoplastic Elastomer (manufactured by Tokyo Material, Inc. (trade name: Engage 8200)) 4.7% by mass

+ Talc (manufactured by Idemitsu Lion Composite Co., Ltd. (trade name: HMP460-1)) 0.3 mass%

Comparative Example 1

As shown in Table 4 below, Comparative Example 1 was formed with the same thickness as in Example 1 with the same thickness, and the first base layer was formed with the following resin formulation.

First base material layer ：

80 mass% of polypropylene (PP) (made by Prime Polymer, Inc. (brand name: E105GM stereoregularity ii92 mol%))

+ Low density polyethylene (LDPE) (made by Nippon Polyethylene Co., Ltd. (brand name: HE30)) 20 mass%

As described above, the flange portion was formed flat using a ring-shaped seal half.

And Comparative Example 1-1 was made to fuse | cover the cover material whose polypropylene (PP) sealant layer mentioned above to the thermoforming container formed from the multilayer sheet of Comparative Example 1 similarly to Example 1-1. . In addition, Comparative Example 1-2 was made to fuse | cover the cover material which is the LLPE mentioned above by the sealant layer to the thermoforming container formed from the multilayer sheet of Comparative Example 1 similarly to Example 1-2.

Comparative Example 2

In Comparative Example 2, as shown in Table 4 below, the surface layer was formed to a thickness of 50 µm with the following resin formulation, and the first base layer was formed in the same formulation as in Example 1, that is, three-dimensional as polypropylene (PP). The thing of regular ii97 mol% (The Prime Polymer Co., Ltd. product (brand name: V300SVE)) was used. In addition, it formed similarly to the comparative example 1.

Surface layer ：

Polypropylene (PP) (Comparative Example 1 and Copper Material) 70% by mass

+ Ethylene acrylic acid ester maleic anhydride copolymer (made by Nippon Polyethylene Co., Ltd. (brand name: ET220X)) 30 mass%

[Comparative Example 3]

As shown in the following Table 4, the comparative example 3 formed the surface layer in thickness of 50 micrometers with the following resin formulation, and formed the 1st base material layer by the same formulation as Example 1. In addition, it formed similarly to the comparative example 1.

Surface layer ：

Polypropylene (PP) (Comparative Example 1 and Copper Material) 70% by mass

+ Low density polyethylene (LDPE) (Example 1 and the same material) 30% by mass

[Comparative Example 4]

As shown in the following Table 4, the comparative example 4 formed the surface layer in thickness of 50 micrometers with the following resin formulation, and formed the 1st base material layer by the same formulation as Example 1. In addition, it formed similarly to the comparative example 1.

Surface layer ：

20% by mass of polypropylene (PP) (comparative example 1 and the same material)

+ 50 mass% of metallocene-based PP (the same material as Example 1)

+ Low density polyethylene (LDPE) (Example 1 and the same material) 30% by mass

[Comparative Example 5]

As shown in the following Table 5, the comparative example 5 formed the surface layer in thickness of 50 micrometers with the following resin formulation, and the 1st base material layer was formed by the same formulation as Example 1. In addition, it formed similarly to the comparative example 1.

Surface layer ：

Polypropylene (PP) (Comparative Example 1 and same material) 75% by mass

+ 5 mass% of metallocene system PP (the same material as Example 1)

+ Low density polyethylene (LDPE) (Example 1 and the same material) 20% by mass

[Comparative Example 6]

In Comparative Example 6, as shown in Table 5 below, the surface layer was formed to a thickness of 50 μm by the following resin formulation, and the first base layer was formed by the same formulation as in Example 1. In addition, it formed similarly to the comparative example 1.

Surface layer ：

Polypropylene (PP) (Comparative Example 1 and the same material) 30% by mass

+ Metallocene system PP (the same material as Example 1) 25 mass%

+ Low density polyethylene (LDPE) (Example 1 and the same material) 45% by mass

[Comparative Example 7]

As shown in the following Table 5, the comparative example 7 formed the surface layer in thickness of 50 micrometers with the following resin formulation, and the 1st base material layer was formed by the same formulation as Example 1. In addition, it formed similarly to the comparative example 1.

Surface layer ：

Polypropylene (PP) (Comparative Example 1 and the same material) 60% by mass

+ Metallocene system PP (the same material as Example 1) 25 mass%

+ Low density polyethylene (LDPE) (Example 1 and the same material) 15% by mass

[evaluation]

The heat resistance, adhesiveness (sealing) property, peeling strength, and opening appearance of Examples 1-1-15-2 and Comparative Examples 1-1-7-2 obtained as mentioned above were compared and evaluated on the following references | standards. The results are shown in Tables 1 to 5 described above.

(Heat resistance)

Heat resistance evaluated the adhesiveness with the heated heating plate which assumed the hot-plate contact heating system at the time of thermoforming of a thermoforming container. Evaluation is three steps below.

A: When not attached to a 170 degreeC heating plate.

B: When not attached to the hot plate of 155 degreeC, but adheres to the hot plate of 170 degreeC.

C: When adhering to the heating plate of 155 degreeC.

(Adhesive (sealed))

The adhesiveness (sealing) property cut | disconnected the side part of the obtained package body by 15 mm width, and made it a test sample, using the tension tester (brand name: digital force gauge / electric stand) from the inside of a flange part to the outside. It measured 8 times at 180 degree peeling and 300 mm / min. Evaluation is the following two steps.

A: At least 8 times of tensile strength is 9.8 N (1.0 kgf).

B: The eight times average of tensile strength is 9.8 N (1.0 kgf) or more.

C: The average of eight times the tensile strength is less than 9.8 N (1.0 kgf).

(Peel strength)

Peel strength was cut to a width of 15 mm at the opening start position at the four corners of the obtained package to obtain a test sample, and 135 ° peeling and 300 mm using the tensile tester described above from the outside of the flange portion. 6 times per minute. Evaluation is three steps below.

A: Tensile strength is more than 6.9 N (0.7 kgf) and less than 11.8 N (1.2 kgf)

B ： Tensile strength of 4.9 N (0.5 kgf) or more and less than 6.9 N (0.7 kgf) or tensile strength of 11.8 N (1.2 kgf) or more and less than 14.7 N (1.5 kgf)

C: Tensile strength is less than 4.9 N (0.5 kgf) or less than 14.7 N (1.5 kgf)

(Opening appearance)

Opening appearance was evaluated by observing the presence or absence of breakage of lint and cover material after opening. Evaluation is the following two steps.

A: No destruction of fluff or cover material occurred.

B: Although some fluff was observed, the destruction of the cover material did not occur.

C: Destruction of fluff and cover material occurs.

[result]

As shown in the said Table 1-Table 5, Examples 1-15 were able to obtain favorable result with all the adhesiveness (sealing) property, peeling strength, and unsealing appearance.

In addition, in Example 3 and Example 5, since the compounding ratio of PP of the surface layer was large, peeling strength was slightly weak. Moreover, in Example 4, since the compounding ratio of PP of the surface layer was small, and low density polyethylene increased, it was confirmed that it was not attached to a hot plate at the time of thermoforming, but it tended to be tensioned. Other than that, it was favorable.

On the other hand, in Comparative Example 5 or Comparative Example 7, which is a compounding compound containing a large proportion of PP and having a low density of polyethylene, the adhesive strength was too strong and did not peel off. Moreover, in the comparative example 6 with many low density polyethylenes, the problem which adhered to the hotplate at the time of thermoforming and interrupted continuous molding was confirmed.

Moreover, in the comparative example 1 whose isotactic pentad fraction of a subsurface layer is 92 mol%, it did not fuse stably at the time of fusion | melting of a cover material, and the variation of adhesiveness and peeling strength was large. On the other hand, in the Example whose isotactic pentad fraction is 97 mol%, stable adhesiveness and peeling strength could be obtained.

And it did not confirm that evaluation differed significantly by the shape of a flange part from Example 1 and Examples 8-10.

From these results, by forming in the compounding range of the present invention, it is possible to easily mold continuously without causing a problem of attaching the multilayer sheet during thermoforming, and to obtain stable sealing properties and to provide a package having stable characteristics. It was confirmed that it can provide.

Industrial availability

The present invention combines high sealing properties and easy opening, and is, for example, a thermoforming container for an easy-opening package that can be widely used as a packaging container for various foods such as retort food, drugs, cosmetics, sundries, and the like. It can be applied to the multi-layered sheet to prepare.

One… Ease of opening package
2… Thermoforming container
3 ... Cover material
6 ... Suzy
20... Multilayer sheet
21 ... Opening
24 ... Flange portion
26 ... Surface layer
27 ... Surface layer
32 ... Sealant layer

Claims (7)

A multilayer sheet constituted by laminating at least two layers of a surface layer and a subsurface layer formed adjacent to the surface layer,
The said surface layer is 30 mass% or more and 70 mass% or less of polypropylene resin, 10 mass% or more and 30 mass% or less of propylene-ethylene random copolymer of melting | fusing point 130 degreeC or less, and low density polyethylene type resin of 120 degreeC or more of melting | fusing point 20 mass% or more and 40 mass% or less are contained,
The said underlayer is a multilayer sheet whose main component is polypropylene resin whose isotactic pentad fraction is 93 mol% or more. The method of claim 1,
The said underlayer contains 80 mass% or more of polypropylene whose isotactic pentad fraction is 93 mol% or more, The multilayer sheet characterized by the above-mentioned. The method of claim 1,
When the content of the polypropylene having an isotactic pentad fraction of 93 mol% or more is less than 80 mass%, the subsurface layer contains talc at 0.5 mass% or more and 5 mass% or less. The method according to any one of claims 1 to 3,
The said surface layer has a thickness dimension of 10 micrometers or more and 150 micrometers or less, The multilayer sheet characterized by the above-mentioned. A thermoforming container obtained by thermoforming the multilayer sheet according to any one of claims 1 to 4 and having an opening,
On the periphery of the opening is formed a flange portion extending outwards,
And the surface layer is formed on an inner surface side of the thermoforming container. The thermoforming container according to claim 5,
An easy-open package, characterized in that the cover member is fused to a flange portion of the thermoforming container to close the opening. The method according to claim 6,
The lid member has a sealant layer on a surface fused to the thermoforming container,
The resin packing part by the said surface layer, the said subsurface layer, and the sealant layer of the said lid | cover material is formed in the vicinity of the opening side of the said flange part, The easy opening package characterized by the above-mentioned.

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