JP6594774B2 - Container body, molded lid and container - Google Patents

Description

  The present invention relates to a container body, a molded lid, and a container.

In the packaging of foods and the like, it is necessary to completely seal the contents contained in the container at the time of distribution and storage before use from the viewpoint of storage stability of the contents. In use, it is desirable that the container can be easily opened.
Conventionally, as an example of such packaging of foods, etc., a container body having a flange portion at the periphery of an opening for storing contents, and a thin top film having a thickness of less than 100 μm are formed on the flange portion of the container body. A heat-sealed container is known (see Patent Document 1).
On the other hand, in recent years, a molding lid in which a sheet-shaped resin material is formed into a predetermined shape by vacuum molding or pressure molding has been used as a lid material covering the opening of the container body (see Patent Document 2). ).

JP 2006-206128 A JP 2012-066832 A

However, when a molded lid is used instead of the top film, the molded lid and the container body are sealed because a predetermined thickness is required to obtain moldability unlike the top film. There was a problem that it was difficult to control the seal when doing so.
Here, as a sheet-like resin material for obtaining a molding lid, it is known to use a polyolefin resin from the viewpoints of moldability, cost, and transparency.

  Therefore, the present invention provides a container having a high hermeticity and an easy-opening property when using a molded lid containing a polyolefin-based resin, since it can be heat-sealed at a low temperature and in a short time, and the sealing control is easy. An object is to provide a main body, a molded lid, and a container.

The container main body of the present invention is used for a container formed by sealing the flange part with a molding lid containing a polyolefin resin so that the flange part is formed at the periphery of the opening part and the opening part is closed. A container body comprising at least two layers of a first layer and a second layer, the second layer comprising a polyolefin-based resin, wherein the first layer comprises: ) To (f). The low crystalline polypropylene is included.
(A) [mmmm] = 20-60 mol%
(B) [rrrr] / (1- [mmmm]) ≦ 0.1
(C) [rmrm]> 2.5 mol%
(D) [mm] × [rr] / [mr] ² ≦ 2.0
(E) Mass average molecular weight (Mw) = 10,000 to 200,000
(F) Molecular weight distribution (Mw / Mn) <4
The container body of the present invention includes a recess formed in at least part of the edge of the opening of the recess, and a flange portion which is sealed with the molded lid comprising a polyolefin resin, the following (a) It comprises at least two layers of a first layer comprising a low crystalline polypropylene satisfying (f) and a second layer comprising a polyolefin-based resin, and the first layer comprises the concave portion in the flange portion. It is characterized in that it is formed on at least a part of a surface continuous with the inner surface of the.
(A) [mmmm] = 20-60 mol%
(B) [rrrr] / (1- [mmmm]) ≦ 0.1
(C) [rmrm]> 2.5 mol%
(D) [mm] × [rr] / [mr] ² ≦ 2.0
(E) Mass average molecular weight (Mw) = 10,000 to 200,000
(F) Molecular weight distribution (Mw / Mn) <4

In this invention, the 1st layer used as a sealing surface with the shaping | molding lid | cover containing polyolefin resin contains low crystalline polypropylene. The low crystalline polypropylene is characterized by a low melting point and high thermal stability.
For this reason, a low temperature sealing property can be provided to a 1st layer because a 1st layer contains low crystalline polypropylene. As a result, even if the molding lid has a certain thickness or more, it can be heat-sealed at a low temperature and in a short time.

In the container main body of the present invention, the content of the low crystalline polypropylene is preferably 5% by mass or more based on the total amount of the first layer.
According to the present invention, since the content of the low crystalline polypropylene is 5% by mass or more based on the total amount of the first layer, an appropriate low temperature sealing property can be imparted to the first layer.
Here, the content of the low crystalline polypropylene in the first layer of the container body is set in accordance with the use environment of the container in addition to the resin configuration and thickness of the molded lid to be sealed. When low crystalline polypropylene is contained only in the first layer of the container body, it is preferably 30% by mass or more, and when the low crystalline polypropylene is contained in the first layer of both the container body and the molding lid. The content of the low crystalline polypropylene in the first layer of the container body is preferably 5% by mass or more. Moreover, the upper limit of the low crystalline polypropylene in the first layer of the container body can be 100% by mass.
In the container body of the present invention, the first layer may contain at least one polypropylene resin selected from the group consisting of homopolypropylene (HPP), random polypropylene (RPP), and block polypropylene.

In the container body of the present invention, it is preferable that the first layer further comprises high-density polyethylene.
According to the invention, the first layer further comprises high density polyethylene. High-density polyethylene is excellent in heat resistance and sealing properties. For this reason, the container main body which is excellent in sealing performance and has favorable openability can be provided by using a high density polyethylene for the first layer.

In the container body of the present invention, the polyolefin resin is preferably a polypropylene resin.
According to the present invention, the polyolefin resin is a polypropylene resin. Polypropylene resins are preferably used because they are widely distributed and easily available, are inexpensive and have high strength. A container body excellent in moldability can be provided by using a polypropylene resin.

The molded lid of the present invention is a molded lid that seals the flange portion so as to close the opening of the container main body, and the side of the container main body that contacts the first layer is a low crystalline polypropylene. It is characterized by comprising.
According to the present invention, the side of the container body that contacts the first layer comprises low crystalline polypropylene. The low crystalline polypropylene is characterized by a low melting point and high thermal stability.
For this reason, the side which contact | connects the 1st layer of a container main body can provide a low temperature sealing property also to a shaping | molding lid because it contains low crystalline polypropylene. As a result, even if the thickness of the molding lid is large, heat sealing can be performed at a low temperature and in a short time. Here, by including low crystalline polypropylene in the first layer of both the container main body and the molding lid, the container main body first is compared with the case where only the first layer of the container main body contains low crystalline polypropylene. It becomes possible to reduce the content of the low crystalline polypropylene in one layer.

In the molding lid of the present invention, the thickness of the molding lid is preferably 0.2 mm or more and 0.5 mm or less.
According to the present invention, the thickness of the molding lid is 0.2 mm or more and 0.5 mm or less. If the thickness of the molding lid is within the above range, the container body and the molding lid can be well heat-sealed at a low temperature and in a short time. If the thickness of the molding lid is less than the lower limit, the moldability of the molding lid may be inferior. On the other hand, when the thickness of the molding lid exceeds the upper limit value, the heat conductivity is deteriorated, so that it is difficult to heat-seal the container body and the molding lid.

The container of the present invention includes the above-described container body and the above-described molding lid.
In this invention, since the container main body and the molding lid described above are provided, the container main body and the molding lid can be heat-sealed at a low temperature in a short time, and a highly sealable and easily openable container can be provided.
Further, the molded lid of the present invention is used for a container formed by sealing a flange portion with a molded lid containing a polyolefin resin so that the flange portion is formed at the periphery of the opening portion and the opening portion is closed. A molded lid that seals the flange portion so as to close the opening of the container body including at least two layers of the first layer and the second layer, and the side that contacts the first layer of the container body is The low crystalline polypropylene satisfying the following (a) to (f) is included.
(A) [mmmm] = 20-60 mol%
(B) [rrrr] / (1- [mmmm]) ≦ 0.1
(C) [rmrm]> 2.5 mol%
(D) [mm] × [rr] / [mr] ² ≦ 2.0
(E) Mass average molecular weight (Mw) = 10,000 to 200,000
(F) Molecular weight distribution (Mw / Mn) <4

It is the schematic which shows the container of this embodiment, and is a perspective view of a container. It is the schematic which shows the container of this embodiment, and is a front view of a container. It is principal part sectional drawing of the container main body of this embodiment. It is principal part sectional drawing of the shaping | molding lid | cover of this embodiment. It is the schematic which shows the container of other embodiment, and is a perspective view of a container. It is the schematic which shows the container of other embodiment, and is a front view of a container.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of each embodiment, the members denoted by the same reference numerals are omitted or simplified.

[Container configuration]
FIG. 1A is a schematic view showing a container according to this embodiment, and is a perspective view of the container. FIG. 1B is a front view of the container.
1A and 1B, the container 1 includes a container body 20 having a substantially rectangular shape in which the contents are stored in the recess 21. In the container body 20, a flange in which a molding lid 30 is disposed at the periphery of the opening portion 22 is provided in the center portion of the container body 20 so as to block the opening portion 22 formed in a substantially rectangular shape facing the bottom surface portion 211 of the recess portion 21. The part 23 is heat-sealed. Here, the molding lid 30 refers to a sheet-shaped resin material having a predetermined three-dimensional shape by vacuum molding or pressure molding. The molding lid 30 includes at least a top plate 31, an inclined surface 32 that is formed around the top plate 31 and expands outward and downward, and a flange 33 that extends outward from the lower end of the inclined surface 32. I have. Heat sealing between the flange portion 23 of the container body 20 and the flange 33 of the molding lid 30 is performed by the annular seal portion 24.
As shown in FIGS. 1A and 1B, the container 1 holds a grip part 34 from which a part of the flange 33 of the molding lid 30 protrudes, and the molding lid 30 sealed by the seal part 24 is connected to the flange part of the container body 20. 23 is peeled off and opened.

[Construction of container body]
As shown in FIG. 2, the container body 20 is formed of a multilayer sheet 10 in which a seal layer 101 as a first layer and a base material layer 102 as a second layer are laminated in this order. . When the container 1 with the molding lid 30 sealed is opened, the container 1 is opened by the delamination of the seal layer 101 and the base material layer 102.
The seal layer 101 is a surface continuous with the inner surface of the recess 21 in the flange portion 23, that is, the innermost layer of the container body 20, and the seal surface 101A on which the molding lid 30 shown in FIGS. 1A and 1B is disposed is the flange portion. 23, the sealing portion 24 is formed by sealing with the molding lid 30.
The base material layer 102 is a main layer of the multilayer sheet 10, and is a layer having an outer surface 102 </ b> A that is adjacent to the seal layer 101 and appears on the outer surface of the container body 20.

Next, each layer of the multilayer sheet 10 constituting the container body 20 will be described in detail.
The sealing layer 101 shown in FIG. 2 is a layer that comes into contact with the contents and is heat-sealed with the molding lid 30 when the multilayer sheet 10 is molded into the shape of the container body 20 as described above. The part heat-sealed with the molding lid 30 is peeled from the container body 20 together with the molding lid 30.

[Structure of seal layer]
As the seal layer 101, a polyolefin resin is preferably used. Specifically, polypropylene resins such as homopolypropylene (HPP), random polypropylene (RPP) and block polypropylene, polyethylene resins such as high density polyethylene (HDPE) and low density polyethylene (LDPE), linear ethylene-α- An olefin copolymer or the like is used. Among these, HDPE is preferably used because it is easy to open and seal. As HDPE, those having a melt index in the range of 0.02 to 50 and a density in the range of 0.940 to 0.975 g / cm ³ are preferably used. The thickness of the seal layer 101 is preferably 5 to 100 μm, and more preferably 10 to 30 μm.

In the present embodiment, the seal layer 101 contains low crystalline polypropylene.
As the low crystalline polypropylene, those satisfying all of the following (a) to (f) are preferable.
(A) [mmmm] = 20-60 mol%
(B) [rrrr] / (1- [mmmm]) ≦ 0.1
(C) [rmrm]> 2.5 mol%
(D) [mm] × [rr] / [mr] ² ≦ 2.0
(E) Mass average molecular weight (Mw) = 10,000 to 200,000
(F) Molecular weight distribution (Mw / Mn) <4

The mesopentad fraction [mmmm] of (a) indicates that the higher this value, the higher the stereoregularity of the polymer, and the mesopentad fraction [mmmm] of the low crystalline polypropylene is preferably 20 to 60 mol%. More preferably, it is 30-50 mol%, More preferably, it is 40-50 mol%.
When the mesopentad fraction [mmmm] of the low crystalline polypropylene is less than 20 mol%, the heat resistance of the seal layer 101 may be lowered. On the other hand, when the mesopentad fraction [mmmm] of the low crystalline polypropylene is more than 60 mol%, the crystallinity becomes too high, and the low temperature sealing property of the resulting seal layer 101 may be lowered.

The mesopentad fraction [mmmm], the racemic pentad fraction [rrrr], and the racemic meso racemic mesopentad fraction [rmrm] of the low crystalline polypropylene were measured by A. Zambelli et al., “Macromolecules, 6,925. In accordance with the method proposed in (1973), the meso fraction, the racemic fraction, and the racemic meso-racemic meso fraction in pentad units in the polypropylene molecular chain measured by the methyl group signal of the ¹³ C-NMR spectrum. Rate. At this time, the triad fractions [mm], [rr] and [mr] of the low crystalline polypropylene can also be calculated.

The measurement of the ¹³ C-NMR spectrum of the low crystalline polypropylene was carried out according to the assignment of the peak proposed by A. Zambelli et al. In “Macromolecules, 8, 687 (1975)” with the following apparatus and conditions. It can be carried out.
From the obtained measurement results, the mesopentad fraction M, the racemic pentad fraction R, and the like are calculated from the following formulas.
[Equipment and conditions]
Apparatus: JNM-EX400 type ¹³ C-NMR apparatus manufactured by JEOL Ltd. Method: complete proton decoupling method concentration: 220 mg / ml
Solvent: 90:10 (volume ratio) of 1,2,4-trichlorobenzene and heavy benzene Mixed solvent temperature: 130 ° C.
Pulse width: 45 °
Pulse repetition time: 4 seconds Integration: 10,000 times [Calculation formula]
M = m / S × 100
R = γ / S × 100
S = Pββ + Pαβ + Pαγ
S: Signal intensity of side chain methyl carbon atoms of all propylene units Pββ: 19.8 to 22.5 ppm
Pαβ: 18.0 to 17.5 ppm Pαγ: 17.5 to 17.1 ppm
γ: Racemic pentad chain: 20.7 to 20.3 ppm
m: Mesopentad chain: 21.7-22.5 ppm

The value of [rrrr] / [1-mmmm] in (b) is an index indicating the uniformity of the regularity distribution of the low crystalline polypropylene.
[Rrrr] / [1-mmmm] of the low crystalline polypropylene is preferably 0.1 or less, more preferably 0.05 or less, and further preferably 0.04 or less. When the value of [rrrr] / [1-mmmm] is 0.1 or less, the quality of the seal layer 101 can be stabilized.
When [rrrr] / [1-mmmm] of polypropylene is more than 0.1, it means that the polypropylene is a mixture of highly ordered polypropylene and atactic polypropylene like general polypropylene, and a sealing layer The quality of 101 may become unstable.
The value of [rrrr] / [1-mmmm] can be calculated from the apparatus and conditions (a) and the calculation formula.

The value of [rmrm] in (c) is an index indicating the randomness of the low crystalline polypropylene. The racemic meso racemic meso fraction [rmrm] of the low crystalline polypropylene is preferably more than 2.5 mol%, more preferably 2.6 mol% or more, and even more preferably 2.7 mol% or more.
If the value of [rmrm] of the low crystalline polypropylene is more than 2.5 mol%, it means that the low crystalline polypropylene has high randomness, and the adhesiveness of the seal layer 101 can be improved.
The value of [rmrm] can be calculated from the apparatus and conditions of (a) above and a calculation formula.

The value of [mm] × [rr] / [mr] ² in (d) is an index indicating the randomness of the low crystalline polypropylene, and the closer this value is to 0.25, the higher the randomness. .
The value of [mm] × [rr] / [mr] ² of the low crystalline polypropylene is preferably 2.0 or less, more preferably more than 0.25 and 1.8 or less, further preferably 0.5 or more and 1 .5 or less.
When the value of [mm] × [rr] / [mr] ² of the low crystalline polypropylene is 2.0 or less, the adhesiveness of the seal layer 101 can be improved.
The value of [mm] × [rr] / [mr] ² can be calculated from the apparatus and conditions (a) and the calculation formula.

(E) The mass average molecular weight (Mw) of the low crystalline polypropylene is preferably 10,000 to 200,000, more preferably 30,000 to 150,000, and still more preferably 50,000 to 150, 000.
When the mass average molecular weight of the low crystalline polypropylene is within the above range, the viscosity of the low crystalline polypropylene is not too low and becomes appropriate, so that the moldability of the seal layer 101 is improved. If the mass average molecular weight of the low crystalline polypropylene is more than 200,000, the viscosity at the time of melting and solution of the low crystalline polypropylene is too high, and the moldability may be deteriorated.
The method for measuring the mass average molecular weight (Mw) will be described together with the method for measuring the molecular weight distribution (Mw / Mn) described later.

(F) The molecular weight distribution Mw / Mn of the low crystalline polypropylene is preferably less than 4, more preferably 3 or less. When the molecular weight distribution Mw / Mn of the low crystalline polypropylene is less than 4, the adhesive strength of the seal layer 101 can be improved.
The molecular weight distribution (Mw / Mn) of the low crystalline polypropylene is calculated from the polystyrene equivalent mass average molecular weight Mw of the low crystalline polypropylene and the polystyrene equivalent number average molecular weight Mn of the low crystalline polypropylene.
The polystyrene-reduced mass average molecular weight Mw and number average molecular weight Mn of the low crystalline polypropylene can be measured by a gel permeation chromatography (GPC) method, for example, by the following apparatus and conditions.

[GPC measuring device]
Column: TOSO GMHHR-H (S) HT
Detector: RI detector for liquid chromatogram WATERS 150C
[Measurement condition]
Solvent: 1,2,4-trichlorobenzene Measurement temperature: 145 ° C
Flow rate: 1.0 ml / min Sample concentration: 2.2 mg / ml
Injection volume: 160 μl
Calibration curve: Universal Calibration
Analysis program: HT-GPC (Ver.1.0)

The low crystalline polypropylene can be produced using, for example, a metallocene catalyst as described in WO2003 / 087172. In particular, those using a transition metal compound in which a ligand forms a cross-linked structure via a cross-linking group are preferred, and in particular, a transition metal compound that forms a cross-linked structure via two cross-linking groups and Metallocene catalysts obtained by combining promoters are preferred.
For example,
(A) General formula (I)

Wherein, M represents a metal element of the periodic table group 3-10 or the lanthanide series, E ¹ and E ² each represent a substituted cyclopentadienyl group, indenyl group, substituted indenyl group, a hetero cyclopentadienyl group A ligand selected from a substituted heterocyclopentadienyl group, an amide group, a phosphide group, a hydrocarbon group, and a silicon-containing group, which forms a cross-linked structure via A ¹ and A ² In addition, they may be the same or different from each other, X represents a σ-bonded ligand, and when there are a plurality of X, the plurality of X may be the same or different, and other X, E ¹ , E ² or Y may be cross-linked. Y represents a Lewis base, and when there are a plurality of Y, the plurality of Y may be the same or different, and may be cross-linked with other Y, E ¹ , E ² or X, and A ¹ and A ² are A divalent bridging group that binds two ligands, a hydrocarbon group having 1 to 20 carbon atoms, a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing group, a germanium-containing group, a tin-containing group _{, -O -, - CO -,} - S -, - SO 2 -, - Se -, - NR 1 -, - PR 1 -, - P (O) R 1 -, - BR 1 - or -AlR ¹ - R ¹ represents a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, which may be the same as or different from each other. q represents an integer of 1 to 5 and represents [(M valence) -2], and r represents an integer of 0 to 3. And (B) (B-1) a compound capable of reacting with the transition metal compound of component (A) or a derivative thereof to form an ionic complex, and the following (B-2 And) a polymerization catalyst containing a component selected from aluminoxane.

  As the transition metal compound of the component (A), the ligand is preferably a (1,2 ′) (2,1 ′) double-bridge type transition metal compound, for example, (1,2′-dimethylsilylene) ( 2,1'-dimethylsilylene) -bis (3-trimethylsilylmethylindenyl) zirconium dichloride.

  Specific examples of the compound of the component (B-1) include triethylammonium tetraphenylborate, tri-n-butylammonium tetraphenylborate, trimethylammonium tetraphenylborate, tetraethylammonium tetraphenylborate, methyl tetraphenylborate (tri- n-butyl) ammonium, benzyl tetraphenylborate (tri-n-butyl) ammonium, dimethyldiphenylammonium tetraphenylborate, triphenyl (methyl) ammonium tetraphenylborate, trimethylanilinium tetraphenylborate, methylpyridinium tetraphenylborate, tetra Benzylpyridinium phenylborate, methyl tetraphenylborate (2-cyanopyridinium), trikis (tetrafluorophenyl) borate triethyla Monium, tetrakis (pentafluorophenyl) borate tri-n-butylammonium, tetrakis (pentafluorophenyl) triphenylammonium borate, tetrakis (pentafluorophenyl) borate tetra-n-butylammonium, tetrakis (pentafluorophenyl) tetraethylammonium borate Benzyl tetrakis (pentafluorophenyl) ammonium borate (tri-n-butyl), methyldiphenylammonium tetrakis (pentafluorophenyl) borate, triphenyl (methyl) ammonium tetrakis (pentafluorophenyl) borate, tetrakis (pentafluorophenyl) boric acid Methylanilinium, tetrakis (pentafluorophenyl) dimethylanilinium borate, tetrakis (pentafluorophenyl) L) Trimethylanilinium borate, methyl pyridinium tetrakis (pentafluorophenyl) borate, benzylpyridinium tetrakis (pentafluorophenyl) borate, methyl tetrakis (pentafluorophenyl) borate (2-cyanopyridinium), benzyl tetrakis (pentafluorophenyl) borate (2-cyanopyridinium), methyl tetrakis (pentafluorophenyl) borate (4-cyanopyridinium), triphenylphosphonium tetrakis (pentafluorophenyl) borate, tetrakis [bis (3,5-ditrifluoromethyl) phenyl] dimethylaniline borate Ferrocenium tetraphenylborate, silver tetraphenylborate, trityl tetraphenylborate, tetraphenylporphyrin manganese tetraphenylborate, Ferrocenium tetrakis (pentafluorophenyl) borate, tetrakis (pentafluorophenyl) borate (1,1′-dimethylferrocenium), tetrakis (pentafluorophenyl) decamethylferrocenium borate, silver tetrakis (pentafluorophenyl) borate, Tetrakis (pentafluorophenyl) trityl borate, tetrakis (pentafluorophenyl) lithium borate, tetrakis (pentafluorophenyl) sodium borate, tetrakis (pentafluorophenyl) borate Teoraphenylporphyrin manganese, tetrafluoroborate silver, hexafluorophosphate, hexa Examples thereof include silver fluoroarsenate, silver perchlorate, silver trifluoroacetate, and silver trifluoromethanesulfonate.

  Examples of the aluminoxane as the component (B-2) include known chain aluminoxanes and cyclic aluminoxanes.

  Also, trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, dimethylaluminum chloride, diethylaluminum chloride, methylaluminum dichloride, ethylaluminum dichloride, dimethylaluminum fluoride, diisobutylaluminum hydride, diethylaluminum hydride, ethylaluminum sesquichloride, etc. A low crystalline polypropylene may be produced by using the organoaluminum compound in combination.

In addition, the seal layer 101 preferably has a configuration in which HDPE includes low crystalline polypropylene. The content of the low crystalline polypropylene is preferably 5% by mass or more, more preferably 30% by mass or more based on the total amount of the seal layer 101.
If the content of the low crystalline polypropylene is less than the lower limit, there is a possibility that an appropriate low temperature sealing property cannot be imparted to the sealing layer 101. For this reason, for example, in the case of sealing with the molding lid 30 having a thickness exceeding 0.5 mm, the heat conductivity is deteriorated, so that heat sealing at a low temperature and in a short time may be difficult. In this case, it is necessary to increase the heat sealing temperature or to increase the sealing time, but the heat at the time of heat sealing may adversely affect the molding lid 30 such as poor appearance or warping. .
Here, for example, in the case of a container such as a microwave oven that is used in an environment exceeding 100 ° C., there is a possibility that deformation may occur. Therefore, the content of the low crystalline polypropylene in the seal layer 101 may be less than 50% by mass. preferable.

[Configuration of base material layer]
A polyolefin resin is used for the base material layer 102. A polyolefin-based resin is preferably used because it hardly flows during heat sealing.
As the polyolefin resin, specifically, polypropylene, polyethylene, and the like are used. In particular, polypropylene is preferably used because it is widely distributed and easily available, is inexpensive, and has high strength.

In particular, as the base material layer 102, a polymer containing at least part of a propylene unit (hereinafter referred to as polypropylene resin, and appropriately referred to as PP) and a polymer including at least part of an ethylene unit (hereinafter referred to as polyethylene resin, as appropriate) It is preferable to use a resin composition in which PP: PE = 20% by mass to 100% by mass: 0% by mass to 80% by mass.
The polypropylene resin is specifically selected from any of four types of homopolypropylene, random polypropylene, block polypropylene, and mixtures thereof. And when heat resistance is considered, it is preferable in order of a homo polypropylene, a block polypropylene, and a random polypropylene. Moreover, when considering the sealing properties with other layers, random polypropylene, block polypropylene, and homopolypropylene are preferable in this order.
In addition, the base material layer 102 can contain various additives in resin.

  As the layer structure of the base material layer 102 in this embodiment, the first base material layer 111 / second base material layer 112 / adhesive layer 113 / barrier layer 114 / adhesive layer 115 / second base material layer 116 / first One substrate layer 117 may be mentioned.

The first base material layers 111 and 117 are main layers in the multilayer sheet 10. As the first base material layers 111 and 117, the above-described polyolefin resin can be suitably used.
The thicknesses of the first base material layers 111 and 117 can be appropriately set according to the strength of the multilayer sheet 10 and the container body 20 formed using the multilayer sheet 10, and are not particularly limited. 600 μm is preferable, and 50 to 400 μm is more preferable. If the thickness is less than the lower limit, the strength of the container body 20 tends to be insufficient.

The second base material layers 112 and 116 are the main layers in the multilayer sheet 10 together with the first base material layers 111 and 117. As the 2nd base material layers 112 and 116, the material similar to the material used by the said 1st base material layers 111 and 117 can be used conveniently. Further, a material different from the material used for the first base material layers 111 and 117 may be used. In addition, an inorganic filler such as talc may be added to the second base material layers 112 and 116 in order to improve rigidity.
The thickness of the second base material layers 112 and 116 can be set as appropriate according to the strength of the multilayer sheet 10 and the container body 20 formed using the multilayer sheet 10, and is not particularly limited, but is 30 to 600 μm. Is preferable, and 50 to 400 μm is more preferable. If the thickness is less than the lower limit, the strength of the container body 20 tends to be insufficient.

The adhesive layers 113 and 115 are layers that adhere the second base material layer 112 and the barrier layer 114, and the barrier layer 114 and the second base material layer 116, respectively. As the adhesive layers 113 and 115, for example, materials such as urethane elastomer, styrene elastomer, maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, and ethylene vinyl acetate (EVA) can be suitably used.
The thickness of the adhesive layers 113 and 115 is preferably 10 to 50 μm, and more preferably 20 to 40 μm.

The barrier layer 114 is a layer using a resin that blocks oxygen. As the barrier layer 114, for example, a material such as saponified ethylene-vinyl acetate copolymer (EVOH), polyvinylidene chloride (PVDC), polyacrylonitrile (PAN), or the like can be suitably used.
The thickness of the barrier layer 114 is preferably 10 to 200 μm, and more preferably 20 to 120 μm.

As a method for producing the multilayer sheet 10 before forming to be the container body 20, a method such as co-extrusion, dry lamination, extrusion lamination, extrusion coating, or a combination of these methods can be employed. The peel strength of each layer can be adjusted by the thickness of each layer, resin selection, blending ratio, and the like.
The container body 20 is obtained by molding the multilayer sheet 10 composed of the seal layer 101 and the base material layer 102 into a desired shape having the flange portion 23. Examples of the forming method include a vacuum forming method and a pressure forming method.

[Configuration of molded lid]
As shown in FIG. 3, the molding lid 30 includes a base material layer 301 and a surface layer 302.
The base material layer 301 is a layer that includes an outer surface 301 </ b> A that is adjacent to the surface layer 302 and appears on the outer surface of the molding lid 30.
The surface layer 302 is the innermost layer of the molding lid 30 and is a layer having a seal surface 302A that is heat-sealed with the flange portion 23 of the container body 20.

For the surface layer 302, a transparent material, for example, a polyolefin-based resin is preferably used. Specifically, a polypropylene resin such as random polypropylene (RPP) or a polyethylene resin such as low density polyethylene (LDPE) is used. Among these, a polypropylene resin is preferably used because it is excellent in moldability. The thickness of the surface layer 302 is preferably 10 μm or more and 250 μm or less, and more preferably 30 μm or more and 100 μm or less.
In the present embodiment, the surface layer 302 preferably contains low crystalline polypropylene. As a low crystalline polypropylene, the thing similar to what was used with the sealing layer 101 of the above-mentioned container main body 20 can be used.
Further, the content of the low crystalline polypropylene in the surface layer 302 is preferably 3% by mass or more based on the total amount of the surface layer 302.

As the base material layer 301, a polyolefin resin similar to the material used for the surface layer 302 can be suitably used. Further, a material different from the polyolefin resin used in the surface layer 302 may be used. The thickness of the base material layer 301 is preferably 100 μm or more and 490 μm or less, and more preferably 170 μm or more and 470 μm or less.
The thickness of the molding lid 30 (the sum of the thickness of the base material layer 301 and the thickness of the surface layer 302) is preferably 0.2 mm or more and 0.5 mm or less, and more preferably 0.25 mm or more and 0.4 mm or less.

As shown in FIGS. 1A and 1B, the forming lid 30 includes a top plate 31, an inclined surface 32 that is formed on the periphery of the top plate 31 and expands downward, and this inclination. It is obtained by molding into a desired shape having at least a flange 33 extending in the outer horizontal direction from the lower end of the surface 32. Examples of the forming method include a vacuum forming method and a pressure forming method.
The molding lid 30 in the present embodiment has excellent transparency in terms of various properties such as cold shock resistance, heat resistance, and rigidity, as well as excellent transparency.

[Sealing method between container body and molded lid]
When sealing and sealing the container body 20 and the molding lid 30, the container body 20 and the molding lid 30 are overlapped, and a part or all of the overlapped region is heat sealed from the molding lid 30 side with a seal disc. Then, it is sealed by close contact. The seal portion 24 formed by heat sealing preferably has an opening start portion 24 </ b> A that protrudes outwardly on the outer periphery thereof. In FIG. 1A and FIG. 1B, since the container shape is a plane substantially rectangular shape, the opening start part 24A is formed in the position corresponding to each vertex of a rectangle, respectively. Since the opening start portion 24A is formed on the seal portion 24, the opening can be easily peeled off from the sharp tip of the opening start portion 24A at the time of opening.
The sealing temperature is a range of 150 ° C. or higher and 240 ° C. or lower, which is a usable temperature range of a sealing board whose surface is coated with a fluororesin (fluorocarbon resin) such as polytetrafluoroethylene and a fluororesin cloth. The inside is preferable. Among these, 160 degreeC or more and 210 degrees C or less are especially preferable. If the sealing temperature is lower than the lower limit, sealing may not be possible. Further, if the sealing temperature exceeds the upper limit value, the molding lid 30 may be melted and fused to the sealing board.
The sealing pressure is preferably 1 MPa to 5 MPa, the sealing time is preferably 1 second to 5 seconds, the sealing pressure is preferably 2 MPa to 4 MPa, and the sealing time is particularly preferably 1.5 seconds to 3 seconds. If it is less than 1 MPa, sufficient seal strength may not be obtained. Moreover, when it exceeds 5 MPa, there is a possibility of causing edge breakage.
By heat-sealing under the above heat-sealing conditions, the container 1 having high sealing performance can be obtained.

[Operational effects of this embodiment]
According to the embodiment as described above, the following effects can be obtained.
(1) In the present embodiment, the sealing layer 101 of the container body 20 includes a low crystalline polypropylene having a low melting point and high thermal stability. For this reason, when the sealing layer 101 contains low crystalline polypropylene, the sealing layer 101 can be provided with a low temperature sealing property. As a result, even if the molding lid 30 has a certain thickness or more, it can be heat-sealed at a low temperature and in a short time.
(2) In the present embodiment, the content of the low crystalline polypropylene in the seal layer 101 is 5% by mass or more based on the total amount of the seal layer 101. Since the content of the low crystalline polypropylene is 5% by mass or more of the seal layer 101, an appropriate low temperature seal property can be imparted to the seal layer 101.
(3) In the present embodiment, the seal layer 101 further includes high-density polyethylene. High-density polyethylene is excellent in heat resistance and sealing properties. For this reason, by using high-density polyethylene for the seal layer 101, it is possible to provide the container body 20 having excellent sealing performance and good opening performance.
(4) In this embodiment, the polyolefin resin of the base material layer 102 is a polypropylene resin. Polypropylene resins are preferably used because they are widely distributed and easily available, are inexpensive and have high strength. The container main body 20 excellent in moldability can be provided by using a polypropylene resin.

(5) In the present embodiment, the surface layer 302 of the molding lid 30 includes low crystalline polypropylene. The low crystalline polypropylene is characterized by a low melting point and high thermal stability. For this reason, the surface layer 302 of the molding lid 30 on the side in contact with the sealing layer 101 of the container body 20 includes low crystalline polypropylene, so that the molding lid 30 can be provided with a low temperature sealing property. As a result, even if the thickness of the molding lid 30 is thick, heat sealing can be performed at a low temperature and in a short time.
(6) In this embodiment, the thickness of the molding lid 30 is 0.2 mm or more and 0.5 mm or less. If the thickness of the molding lid 30 is within the above range, the container body 20 and the molding lid 30 can be heat-sealed well at a low temperature and in a short time.

(7) In this embodiment, since the container main body 20 and the molding lid 30 described above are provided, the container main body 20 and the molding lid 30 can be heat-sealed at a low temperature in a short time, and high sealing performance and easy An openable container 1 can be provided.

[Modification of Embodiment]
The aspect described above shows one aspect of the present invention, and the present invention is not limited to the above-described embodiment, and has the configuration of the present invention and can achieve the object and effect. It goes without saying that modifications and improvements within the scope are included in the content of the present invention. In addition, the specific structure and shape in carrying out the present invention may be used as other structures and shapes within the scope of achieving the object and effect of the present invention. The present invention is not limited to the above-described embodiments, and modifications and improvements within the scope that can achieve the object of the present invention are included in the present invention.

For example, in the present embodiment, the container body 20 has a configuration in which the base material layer 102 composed of seven layers and the one sealing layer 101 are laminated, but the present invention is not limited to this. The base material layer 102 may be a single layer, or when the base material layer 102 has a multilayer structure, it may be 2 to 6 layers, 8 layers or more. For example, the layer structure of the container body 20 may be the following layer structure.
(A) Seal layer / base material layer (b) Seal layer / base material layer / barrier layer (c) Seal layer / base material layer / second base material layer / barrier layer (d) Seal layer / base material layer / barrier Layer / base material layer (e) seal layer / base material layer / barrier layer / base material layer / outer surface layer (f) seal layer / base material layer / second base material layer / barrier layer / second base material layer (g) ) Seal layer / base material layer / second base material layer / barrier layer / second base material layer / base material layer (h) seal layer / base material layer / second base material layer / barrier layer / second base material layer / Base material layer / Outer surface layer

Moreover, in the said embodiment, although the shape of the container 1 was made into the planar rectangular shape, it is not restricted to this, A planar circular shape and another shape may be sufficient.
Moreover, although the shaping | molding lid 30 demonstrated in the said embodiment the example comprised from the base material layer 301 and the surface layer 302, it is not limited to this. The molding lid 30 may be a single layer, or three or more layers when the molding lid 30 has a multilayer structure.
Moreover, although the surface layer 302 of the shaping | molding lid 30 demonstrated the example in which the low crystalline polypropylene was contained in the said embodiment, the surface layer 302 does not need to contain a low crystalline polypropylene.
Moreover, in the said embodiment, when the container 1 was opened, it was set as the structure which peels between the sealing layer 101 and the base material layer 102 of the container main body 20, However, The multilayer sheet 10 is made into the multilayered structure of three or more layers, and a container main body When 20 is formed, a layer adjacent to the seal layer 101 may be agglomerated and separated.

And in the said embodiment, it is not restricted to the case where the periphery of the shaping | molding lid 30 is cyclically sealed by the flange part 23. FIG. For example, as shown in FIG. 4A and FIG. 4B, a configuration in which a window part 35 with a part cut away is provided as the molding lid 30 and the molding lid 30 is attached so that the opening 22 is partially opened. Good. Further, the molding lid 30 in the embodiment is not limited to the annular seal, and may be discontinuously sealed as indicated by a dotted line.
Moreover, although the container main body 20 was formed so that the sealing layer 101 might become an innermost layer, it is not this limitation. For example, the sealing layer 101 is provided on a surface continuous with the outer surface of the concave portion 21 in the flange portion 23, and the flange 33 of the molding lid 30 is disposed on the side opposite to the opening direction of the opening portion 22 from the peripheral side of the flange portion 23 of the container body 20. You may make it seal so that it may wrap around to the surface which faces.
And attachment (sealing) of the container main body 20 and the shaping | molding lid | cover 30 can utilize not only heat sealing but various methods, such as welding by an ultrasonic wave and adhesion | attachment by an adhesive agent or an adhesive.

Examples of the present invention will be described below, but the present invention is not limited to these examples.
In addition, the measuring method and evaluation method of the physical property shown in the Example and the comparative example are as follows.

[Examples 1-7]
(1) Manufacture of container body A laminate for forming a container body having a thickness of 500 μm and having the following layer structure was formed by coextrusion molding. In the description of the configuration of the container body forming laminate below, the numerical value related to the ratio described in parentheses indicates the content of the component in each layer, and the numerical value related to the length indicates the thickness in each layer.

(Configuration of laminate for container body formation)
Seal layer: polyethylene (60 to 95% by mass) + low crystalline polyethylene (5 to 40% by mass) (20 μm)
Surface lower layer: polypropylene (80% by mass) + polyethylene (20% by mass) (190 μm)
Base material layer: inorganic substance (50 mass%) + polypropylene (45 mass%) + polyethylene (5 mass%) (100 μm) / polypropylene (90 μm) / inorganic substance (50 mass%) + polypropylene (45 mass%) + polyethylene (5 (Mass%) (100 μm) Laminate Next, the container body-forming laminate was vacuum formed to obtain a flanged container body with dimensions of 126 mm × 126 mm × 20 mm.

(2) Production of molded lid A molded lid-forming laminate having a layer structure shown below and having a thickness of 300 μm was molded by coextrusion molding. In the description of the configuration of the molded lid forming laminate below, the numerical value related to the ratio described in parentheses indicates the content of the component in each layer, and the numerical value related to the length indicates the thickness in each layer.

(Configuration of molded lid forming laminate)
Seal layer: polyethylene (90-100% by mass) + low crystalline polyethylene (0-10% by mass) (50 μm)
Base Material Layer: Polypropylene (250 μm) Laminate Next, this molded lid forming laminate was subjected to air pressure molding to obtain a molded lid having dimensions of 126 mm × 126 mm × 20 mm.

(3) Sealing of container body and molded lid The molded body container and molded lid were sealed based on the following sealing conditions and the specifications of the seal disc.

(Sealing conditions)
Sealing temperature: 160 ° C
Seal pressure: 0.3 MPa
Sealing time: 2.0 to 5.0 seconds Number of heat sealing: 2 times

(Seal board specifications)
Seal width: 7mm Surface treatment: Polytetrafluoroethylene coating

[Comparative Examples 1 and 2]
(1) Manufacture of container body A laminate for forming a container body having a thickness of 500 μm and having the following layer structure was formed by coextrusion molding. In the description of the configuration of the container body forming laminate below, the numerical value related to the ratio described in parentheses indicates the content of the component in each layer, and the numerical value related to the length indicates the thickness in each layer.

(Configuration of laminate for container body formation)
Seal layer: Polyethylene (20μm)
Surface lower layer: polypropylene (80% by mass) + polyethylene (20% by mass) (190 μm)
Base material layer: inorganic substance (50 mass%) + polypropylene (45 mass%) + polyethylene (5 mass%) (100 μm) / polypropylene (90 μm) / inorganic substance (50 mass%) + polypropylene (45 mass%) + polyethylene (5 (Mass%) (100 μm) Laminate Next, the container body-forming laminate was vacuum formed to form a flanged container body with dimensions of 126 mm × 126 mm × 20 mm.

(2) Production of molded lid Using a molded lid forming laminate having the same layer structure as in Examples 1 to 7, this molded lid forming laminate was subjected to pressure molding, and a molding lid having dimensions of 126 mm × 126 mm × 20 mm. Was molded.

(3) Sealing between container body and molding lid The molded body container and molding lid were sealed under the same conditions as in the above examples.

[Evaluation test]
The following evaluation tests were performed on the containers obtained in Examples 1 to 7 and Comparative Examples 1 and 2. The results are shown in Table 1 below.

(Sealability)
The mold lid was grasped and lifted up to evaluate whether it was adhered to the container body.
The evaluation items were “A” when the molded lid and the container main body were bonded, and “B” when the molded lid and the container main body were not bonded.
(Sealing)
The container was submerged in water, and the ceiling surface (molded lid) and bottom surface (container body) of the container were pushed in water, and the presence or absence of air leakage generated from inside the container was visually confirmed.
The evaluation items were “A” when no air leakage from the container was confirmed, and “B” when air leakage from the container was confirmed.
(Openability)
Five testers opened the sealed container and evaluated whether it could be opened easily.
The evaluation item is “A” when all five testers are determined to be easily opened, and one to four of the testers are determined to be easily open, and the remaining testers have a feeling of opening. The case where it was judged that it was light was set to "B", and the case where all five testers judged that the opening feeling was light was set to "C".
(Seal strength)
The gripping part of the molding lid was gripped and pulled upward at an angle of 90 degrees with respect to the plane of the flange part of the container body, the maximum value of the tensile strength was measured three times, and the average value was calculated. For measurement, a digital force gauge DPS-20 manufactured by Imada Co., Ltd. was used.

DESCRIPTION OF SYMBOLS 1 Container 20 Container main body 22 Opening part 23 Flange part 30 Molding lid 101 The sealing layer which is a 1st layer 102 The base material layer which is a 2nd layer

Claims (10)

A container main body used for a container formed by sealing a flange portion with a molding lid containing a polyolefin resin so that a flange portion is formed at a peripheral edge of the opening portion and closing the opening portion. ,
Comprising at least two layers, a first layer and a second layer;
The second layer comprises a polyolefin resin,
The container main body characterized in that the first layer comprises low crystalline polypropylene satisfying the following (a) to (f).
(A) [mmmm] = 20-60 mol%
(B) [rrrr] / (1- [mmmm]) ≦ 0.1
(C) [rmrm]> 2.5 mol%
(D) [mm] × [rr] / [mr] ² ≦ 2.0
(E) Mass average molecular weight (Mw) = 10,000 to 200,000
(F) Molecular weight distribution (Mw / Mn) <4 A concave portion, and a flange portion formed on at least a part of the edge of the opening of the concave portion and sealed with a molding lid containing a polyolefin-based resin,
Comprising at least two layers of a first layer comprising a low crystalline polypropylene satisfying the following (a) to (f) and a second layer comprising a polyolefin resin,
The container body according to claim 1, wherein the first layer is formed on at least a part of a surface continuous with an inner surface of the concave portion in the flange portion.
(A) [mmmm] = 20-60 mol%
(B) [rrrr] / (1- [mmmm]) ≦ 0.1
(C) [rmrm]> 2.5 mol%
(D) [mm] × [rr] / [mr] ² ≦ 2.0
(E) Mass average molecular weight (Mw) = 10,000 to 200,000
(F) Molecular weight distribution (Mw / Mn) <4 In the container main body according to claim 1 or 2,
The container main body characterized in that the content of the low crystalline polypropylene is 5% by mass or more based on the total amount of the first layer. In the container main body according to any one of claims 1 to 3,
The container main body characterized in that the first layer contains at least one polypropylene resin selected from the group consisting of homopolypropylene (HPP), random polypropylene (RPP), and block polypropylene. In the container main body according to any one of claims 1 to 4,
The container main body characterized in that the first layer further comprises high-density polyethylene. In the container main body according to any one of claims 1 to 5,
The container body, wherein the polyolefin resin is a polypropylene resin. A molded lid that seals the flange portion so as to close the opening of the container body according to any one of claims 1 to 6,
The molding lid characterized in that the side of the container body that contacts the first layer comprises the low crystalline polypropylene. The molding lid according to claim 7,
A molding lid, wherein the molding lid has a thickness of 0.2 mm to 0.5 mm. The container body according to any one of claims 1 to 6,
A container comprising the molded lid according to claim 7 or 8. A flange is formed at the periphery of the opening, and is used for a container formed by sealing the flange with a molding lid containing a polyolefin-based resin so as to close the opening.
A molded lid that seals the flange portion so as to close the opening of the container body including at least two layers of a first layer and a second layer,
The molding lid characterized in that the side of the container main body in contact with the first layer comprises low crystalline polypropylene satisfying the following (a) to (f) .
(A) [mmmm] = 20-60 mol%
(B) [rrrr] / (1- [mmmm]) ≦ 0.1
(C) [rmrm]> 2.5 mol%
(D) [mm] × [rr] / [mr] ² ≦ 2.0
(E) Mass average molecular weight (Mw) = 10,000 to 200,000
(F) Molecular weight distribution (Mw / Mn) <4

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