JP7310041B1 - LAMINATED SHEET AND FOOD PACKAGING CONTAINER - Google Patents

Abstract

An object of the present invention is to provide an inorganic powder-containing laminated sheet with improved surface smoothness variation, and a food packaging container comprising the inorganic powder-containing laminated sheet with improved surface smoothness variation. is.
The present invention provides a laminated sheet having three or more layers, the laminated sheet comprising at least an inner layer, and a first outer layer and a second outer layer laminated on the surface of the inner layer, wherein the inner layer contains an inorganic substance powder and a thermoplastic resin, the first outer layer and the second outer layer each contain a thermoplastic resin, and the particle size distribution of the inorganic substance powder satisfies predetermined requirements. do.
[Selection figure] None

Description

TECHNICAL FIELD The present invention relates to a laminated sheet and a food packaging container.

In recent years, from the viewpoint of environmental protection, attempts have been made to reduce the content of resin components in various resin products.
Examples of such attempts include increasing the blending amount of calcium carbonate and the like in resin products (for example, Patent Documents 1 and 2).

Japanese Patent No. 6857428 Japanese Patent No. 7113579

On the other hand, a resin product containing a high content of calcium carbonate has a low environmental impact, but the surface smoothness of the product tends to vary. Such variations may impair the quality stability of the appearance of resin products.

The present invention has been made in view of the above circumstances, and a first object of the present invention is to provide a laminated sheet containing an inorganic substance powder, in which variations in surface smoothness are improved.
A second object of the present invention is to provide a food packaging container made of a laminated sheet containing an inorganic substance powder, which is improved in unevenness in surface smoothness.

The inventors of the present invention have found that the above problems can be solved by using an inorganic powder that satisfies a predetermined particle size distribution for the laminated sheet, and have completed the present invention. More specifically, the present invention provides:

(1) A laminated sheet having three or more layers,
The laminated sheet comprises at least an inner layer and a first outer layer and a second outer layer laminated on the surface of the inner layer,
The inner layer contains an inorganic powder and a thermoplastic resin,
The first outer layer and the second outer layer each contain a thermoplastic resin,
The content of the inorganic substance powder is 40.0% by mass or more and 80.0% by mass or less with respect to the laminated sheet,
The particle size distribution D60 of the inorganic substance powder is 6.1 μm or more and 9.2 μm or less,
The particle size distribution D70 of the inorganic substance powder is 7.7 μm or more and 11.5 μm or less,
The particle size distribution D80 of the inorganic substance powder is 10.0 μm or more and 14.1 μm or less,
The particle size distribution D90 of the inorganic substance powder is 13.7 μm or more and 18.1 μm or less,
The particle size distribution D97 of the inorganic substance powder is 19.1 μm or more and 24.5 μm or less,
the proportion of the inorganic substance powder in the inner layer is higher than the proportion of the total amount of the inorganic substance powder in the first outer layer and the second outer layer;
The thickness ratios of the first outer layer and the second outer layer are respectively 2.0% or more and 20.0% or less with respect to the total thickness of the laminated sheet.
Laminated sheet.

(2) the inorganic substance powder has a particle size distribution D60 of 6.1 μm or more and 8.2 μm or less;
The particle size distribution D70 of the inorganic substance powder is 7.7 μm or more and 9.8 μm or less,
The particle size distribution D80 of the inorganic substance powder is 10.0 μm or more and 12.0 μm or less,
The particle size distribution D90 of the inorganic substance powder is 13.7 μm or more and 15.6 μm or less,
The particle size distribution D97 of the inorganic substance powder is 19.1 μm or more and 21.4 μm or less.
The laminated sheet according to (1).

(3) the particle size distribution D60 of the inorganic substance powder is more than 6.5 μm and 8.0 μm or less;
The particle size distribution D70 of the inorganic substance powder is more than 7.9 μm and 9.8 μm or less,
The particle size distribution D80 of the inorganic substance powder is 10.0 μm or more and 12.0 μm or less,
The particle size distribution D90 of the inorganic substance powder is 13.7 μm or more and 15.6 μm or less,
The particle size distribution D97 of the inorganic substance powder is 19.1 μm or more and 21.4 μm or less.
The laminated sheet according to (1).

(4) The laminated sheet according to (1), wherein the inorganic substance powder has a particle size distribution D99 of 23.3 μm or more and 33.5 μm or less.

(5) According to (1), at least one of the thermoplastic resins in the inner layer, the first outer layer, and the second outer layer contains a polypropylene-based resin and/or a polyethylene-based resin. Laminated sheet.

(6) The laminated sheet according to (5), wherein the polyethylene-based resin includes high-density polyethylene and/or linear low-density polyethylene.

(7) The laminated sheet according to (5), wherein the polypropylene-based resin contains a polypropylene block polymer.

(8) The laminated sheet according to (1), wherein the inorganic substance powder contains calcium carbonate particles.

(9) The laminated sheet according to (8), wherein the calcium carbonate particles contain heavy calcium carbonate particles.

(10) The thickness ratios of the first outer layer and the second outer layer are respectively 2.0% or more and 10.0% or less with respect to the total thickness of the laminated sheet, (1) Laminated sheet according to.

(11) The laminated sheet according to any one of (1) to (10), which is a laminated sheet for vacuum forming.

(12) A food packaging container formed from the laminated sheet of (11).

(13) A food packaging container made of laminated sheets of three or more layers,
The laminated sheet comprises at least an inner layer and a first outer layer and a second outer layer laminated on the surface of the inner layer,
The inner layer contains an inorganic powder and a thermoplastic resin,
The first outer layer and the second outer layer each contain a thermoplastic resin,
The content of the inorganic substance powder is 40.0% by mass or more and 80.0% by mass or less with respect to the food packaging container,
The particle size distribution D60 of the inorganic substance powder is 6.1 μm or more and 9.2 μm or less,
The particle size distribution D70 of the inorganic substance powder is 7.7 μm or more and 11.5 μm or less,
The particle size distribution D80 of the inorganic substance powder is 10.0 μm or more and 14.1 μm or less,
The particle size distribution D90 of the inorganic substance powder is 13.7 μm or more and 18.1 m or less,
The particle size distribution D97 of the inorganic substance powder is 19.1 μm or more and 24.5 μm or less,
the content of the inorganic substance powder in the inner layer is greater than the total content of the inorganic substance powder in the first outer layer and the second outer layer;
In at least a part of the cross section of the food packaging container, the ratio of the thicknesses of the first outer layer and the second outer layer to the total thickness of the laminated sheet is 2.0% or more. .0% or less,
Food packaging container.

(14) A laminated sheet for producing the food packaging container of (13) by vacuum forming.

According to the present invention, there are provided an inorganic powder-containing laminated sheet with improved surface smoothness variation, and a food packaging container comprising the inorganic powder-containing laminated sheet with improved surface smoothness variation.

Embodiments of the present invention will be described below, but the present invention is not limited thereto.

<Laminated sheet>
A laminated sheet according to one aspect of the present invention has a structure of three or more layers (that is, an inner layer and a first outer layer and a second outer layer laminated on the surface of the inner layer) and satisfies all of the following requirements.
- The inner layer contains an inorganic powder and a thermoplastic resin.
- A 1st outer layer and a 2nd outer layer each contain a thermoplastic resin.
- The content of the inorganic substance powder is 40.0% by mass or more and 80.0% by mass or less with respect to the laminated sheet.
- The particle size distribution D60 of the inorganic substance powder is 6.1 µm or more and 9.2 µm or less.
- The particle size distribution D70 of the inorganic substance powder is 7.7 µm or more and 11.5 µm or less.
- The particle size distribution D80 of the inorganic substance powder is 10.0 µm or more and 14.1 µm or less.
- The particle size distribution D90 of the inorganic substance powder is 13.7 µm or more and 18.1 µm or less.
- The particle size distribution D97 of the inorganic substance powder is 19.1 µm or more and 24.5 µm or less.
- The ratio of the inorganic substance powder in the inner layer is higher than the ratio of the total amount of the inorganic substance powder in the first outer layer and the second outer layer.
- The thickness ratios of the first outer layer and the second outer layer are respectively 2.0% or more and 20.0% or less with respect to the total thickness of the laminated sheet.

Whether or not the laminated sheet satisfies the requirements of the present invention can be identified based on scanning electron microscope (SEM) images.
Specifically, the thickness of each layer and the content of the component contained in each layer can be specified by analyzing SEM images such as the cross section of the laminated sheet.
In addition, whether the laminated sheet satisfies the requirements for the particle size distribution of the inorganic substance powder, the type of the inorganic substance powder contained in the laminated sheet, and the like can be specified by a method using a laser diffraction particle size distribution measuring device, which will be described later.

Laminated sheets containing a high amount of inorganic powder tend to have uneven surface smoothness due to the low dispersibility of the inorganic powder.
For example, in order to improve the surface smoothness of the laminated sheet, the particle size of the inorganic substance powder is adjusted (for example, the average particle size of the inorganic substance powder is adjusted to a predetermined range, or the particle size of the inorganic substance powder is adjusted. adjustment of the maximum particle size to a predetermined value or less) or use of a dispersant.
Conventionally, however, attention has not been focused on stabilizing the quality of laminated sheets and molded articles obtained from the laminated sheets during mass production, that is, variations in surface smoothness during mass production.

Under the circumstances described above, as a result of investigations by the present inventors, it was unexpectedly found that the particle size distribution of the inorganic substance powder has a great effect on variations in surface smoothness during mass production. . The finding that it is easy to suppress variations in surface smoothness by blending so as to satisfy the particle size distribution of the present invention is extremely surprising.

In the present invention, the "surface smoothness of the laminated sheet" includes the surface smoothness (surface smoothness) at the time of production of the laminated sheet and the surface smoothness (surface smoothness) of the obtained laminated sheet.

In the present invention, the "surface smoothness of the food packaging container" includes the surface smoothness (surface smoothness) of the food packaging container.

In the present invention, "variation in surface smoothness is suppressed" means that when a large number of laminated sheets themselves or molded products (food packaging containers, etc.) from laminated sheets are produced under the same conditions, there is a gap between them. It means that there is little variation (deviation) in the degree of surface smoothness.

The surface smoothness of laminated sheets and food packaging containers can be evaluated based on the arithmetic mean height according to JIS B0601:2001.

In the present invention, "consisting of component A" means that components other than component A are not substantially included.

In the present invention, "substantially free of component B" means that the content of component B is less than 0.1% by mass with respect to the entire compounding object (e.g., laminated sheet), more preferably Embodiments in which the content is 0.01% by mass or less, and more preferably embodiments in which Component B is not contained at all are included.

The configuration of the laminated sheet of the present invention will be described in detail below.

(1) Inorganic Powder Contained in Laminated Sheet The main technical feature of the present invention is that the particle size distribution of the inorganic powder is adjusted while a high proportion of the inorganic powder is blended.

(1-1) Content of inorganic substance powder in laminated sheet The content of the inorganic substance powder is 40.0% by mass or more and 80.0% by mass or less with respect to the laminated sheet.
Such a laminated sheet with a high content of inorganic substance powder has a serious problem that the surface smoothness tends to vary. However, in the present invention, the variation in surface smoothness can be suppressed by adjusting the particle size distribution of the inorganic powder, which will be described later.

Even if the content of the inorganic substance powder is high, variations in surface smoothness are unlikely to occur. be.

The content of the inorganic substance powder is 80.0 mass or less, preferably 75.0 mass or less, more preferably 75.0 mass or less, with respect to the laminated sheet, from the viewpoint of blending a thermoplastic resin that imparts sufficient surface smoothness. It is 70.0% by mass or less.

(1-2) Particle Size Distribution of Inorganic Substance Powder in Laminated Sheet The inorganic substance powder contained in the laminated sheet of the present invention is adjusted so that the cumulative distribution of particle diameters thereof satisfies predetermined requirements.

In the present invention, “the particle size distribution Dn is X μm” means that “n%” of the particle population has a particle diameter of “X μm or less”, in other words, “n%” of the particle population means that the upper limit of the particle size of is "X μm".
In the present invention, "the particle size distribution Dn of the inorganic substance powder is A µm or more and B µm or less" means that "n%" of the entire inorganic substance powder has a value within the range of "A µm or more and B µm or less" as an upper limit. It means having a particle size that
For example, "D50 is 1 μm or more and 2 μm or less" means that half (50%) of the particles of the entire inorganic substance powder have a particle diameter with an upper limit of a value within the range of 1 μm or more and 2 μm or less. means. In this example, half the particles have a particle size of, for example, 1 μm or less, 1.5 μm or less, or 2 μm or less.

In the present invention, a laser diffraction particle size distribution analyzer is used as a device for measuring the particle size distribution Dn and the particle size of the inorganic powder.
More specifically, based on the ash content obtained by firing the sheet or molded product, inorganic substances contained in the laminated sheet and the molded product obtained from the laminated sheet are measured using a laser diffraction/scattering particle size distribution measuring device. The particle size distribution of powder can be specified.

In the present invention, each lower limit and each upper limit of the particle size distribution below can be independently combined.

The particle size distribution D60 of the inorganic substance powder contained in the entire laminated sheet is 6.1 μm or more and 9.2 μm or less.
From the viewpoint that the effects of the present invention are likely to be exhibited, the lower limit of the particle size distribution D60 is 6.1 μm or more, preferably more than 6.5 μm.
The upper limit of the particle size distribution D60 is 9.2 μm or less, preferably 8.2 μm or less, more preferably 8.0 μm or less, from the viewpoint that the effects of the present invention are likely to be exhibited.

The particle size distribution D70 of the inorganic substance powder contained in the entire laminated sheet is 7.7 μm or more and 11.5 μm or less.
From the viewpoint that the effects of the present invention are likely to be exhibited, the lower limit of the particle size distribution D70 is 7.7 μm or more, preferably more than 7.9 μm.
The upper limit of the particle size distribution D70 is 11.5 μm or less, preferably 9.8 μm or less, from the viewpoint that the effects of the present invention are likely to be exhibited.

The particle size distribution D80 of the inorganic substance powder contained in the entire laminated sheet is 10.0 μm or more and 14.1 μm or less.
The lower limit of the particle size distribution D80 is 10.0 μm or more, preferably 10.5 μm or more, from the viewpoint that the effects of the present invention are likely to be exhibited.
The upper limit of the particle size distribution D80 is 14.1 μm or less, preferably 12.0 μm or less, from the viewpoint that the effects of the present invention are likely to be exhibited.

The particle size distribution D90 of the inorganic substance powder contained in the entire laminated sheet is 13.7 μm or more and 18.1 μm or less.
The lower limit of the particle size distribution D90 is 13.7 μm or more, preferably 14.0 μm or more, from the viewpoint that the effects of the present invention are likely to be exhibited.
The upper limit of the particle size distribution D90 is 18.1 m or less, preferably 15.6 µm or less, from the viewpoint that the effects of the present invention are likely to be exhibited.

The particle size distribution D97 of the inorganic substance powder contained in the entire laminated sheet is 19.1 μm or more and 24.5 μm or less.
The lower limit of the particle size distribution D97 is 19.1 μm or more, preferably 19.1 μm or more, from the viewpoint that the effects of the present invention are likely to be exhibited.
The upper limit of the particle size distribution D97 is 24.5 μm or less, preferably 21.4 μm or less, from the viewpoint that the effects of the present invention are likely to be exhibited.

In the inorganic substance powder contained in the entire laminated sheet, the smaller the particles having a large particle size (for example, the particles having a diameter of 32.0 μm or more), the easier it is to improve the moldability of the laminated sheet during mass production.
Therefore, in one aspect of the present invention, the lower limit of the particle size distribution D99 in the inorganic substance powder contained in the laminated sheet is preferably 23.3 μm or more.
In one aspect of the present invention, the upper limit of the particle size distribution D99 of the inorganic substance powder contained in the laminated sheet is preferably 33.5 μm or less, more preferably 26.4 μm or less.

The method for preparing the inorganic powder that satisfies all the requirements for particle size distribution in the present invention is not particularly limited, but examples thereof include the following methods.
- Inorganic powders (commercially available products, etc. may be used) whose particle size distribution is specified in advance are blended so as to satisfy the particle size distribution in the present invention.
- If necessary, the blended product is passed through a pore size filter to adjust the particle size distribution.
- If necessary, inorganic substance powder having a predetermined particle size with an extremely narrow particle size distribution is added to the blended product to adjust the particle size distribution.

(1-3) Kinds of Inorganic Powder in Laminated Sheets The inorganic powder is not particularly limited, and may be those contained in ordinary resin products or the like. As the inorganic powder, one type of substance may be used alone, or two or more types of substances may be used in combination.

The inorganic powder contained in each layer of the laminated sheet may be the same substance or different substances.
However, from the viewpoint that the effect of the present invention can be easily exhibited, it is preferable that all the inorganic substance powders contained in each layer in the laminated sheet are the same substance.
Further, as will be described later, in the laminated sheet, the ratio of the inorganic substance powder in the inner layer is adjusted to be higher than the ratio of the total amount of the inorganic substance powder in the first outer layer and the second outer layer, but the effect of the present invention is From the viewpoint of being particularly easy to perform, it is preferable that the inorganic substance powder is contained only in the inner layer.

Examples of inorganic substance powders include the following.
Carbonates, sulfates, silicates, phosphates, or borates of metals (calcium, magnesium, aluminum, titanium, iron, zinc, etc.);
oxides of metals (calcium, magnesium, aluminum, titanium, iron, zinc, etc.);
hydrates of the above salts or oxides;

Examples of inorganic substance powders include calcium carbonate, magnesium carbonate, zinc oxide, titanium oxide, silica, alumina, clay, talc, kaolin, aluminum hydroxide, magnesium hydroxide, aluminum silicate, magnesium silicate, calcium silicate, aluminum sulfate, magnesium sulfate, calcium sulfate, magnesium phosphate, barium sulfate, silica sand, carbon black, zeolite, molybdenum, diatomaceous earth, sericite, shirasu, calcium sulfite, sodium sulfate, potassium titanate, bentonite, graphite and the like.

The inorganic substance powder may be synthetic or derived from natural minerals.

In order to enhance the dispersibility and reactivity of the inorganic powder, the surface of the inorganic powder may or may not be previously surface-modified according to a conventional method.
Surface modification methods include physical treatment methods (plasma treatment, etc.), chemical treatment methods (methods using a coupling agent or surfactant), and the like.

The shape of the inorganic powder is not particularly limited, and may be particulate (spherical, irregular, etc.), flakes, granules, fibers, or the like.

The inorganic substance powder preferably contains calcium carbonate. For example, the inorganic substance powder preferably contains 70% by mass or more, more preferably 80% by mass or more, and most preferably 100% by mass of calcium carbonate.
Laminated sheets highly filled with calcium carbonate are particularly inferior in surface smoothness stability. However, according to the present invention, even when the laminated sheet contains calcium carbonate, it is possible to satisfactorily suppress variations in surface smoothness.

Whether calcium carbonate is contained in the inorganic substance powder in the laminated sheet and its content can be identified by firing the laminated sheet and analyzing its ash content.

Calcium carbonate may be either heavy calcium carbonate or light calcium carbonate.
“Heavy calcium carbonate” is calcium carbonate obtained by mechanically pulverizing (dry method, wet method, etc.) a natural raw material (limestone, etc.) containing CaCO ₃ as a main component.
"Light calcium carbonate" is calcium carbonate prepared by a synthetic method (such as a chemical precipitation reaction).
Therefore, heavy calcium carbonate and light calcium carbonate are clearly distinguished from each other.

The difference between heavy calcium carbonate and light calcium carbonate can be identified, for example, from the circularity calculated based on the analysis of SEM images.
The roundness of the heavy calcium carbonate powder is, for example, in the range of 0.50 or more and 0.95 or less. The circularity of the light calcium carbonate powder is, for example, approximately 1.00.

In the present invention, the "circularity" is a value represented by the following formula, and is an index of the degree of amorphousness of particles. The closer the circularity is to "1" (maximum value), the closer to a perfect circle, and the lower the circularity, the higher the degree of irregularity.
"Circularity" = (projected area of particle) / (area of circle having the same perimeter as projected perimeter of particle)

Since heavy calcium carbonate is not uniform in shape and the like due to its manufacturing method, the surface smoothness of the laminated sheet tends to vary during mass production. However, according to the present invention, by adjusting the particle size distribution, it is possible to satisfactorily suppress variations in surface smoothness even in the case of a laminated sheet highly filled with heavy calcium carbonate.
Therefore, in a preferred embodiment of the invention, the laminated sheet comprises ground calcium carbonate. In a more preferred embodiment of the present invention, the inorganic substance powder contained in the laminated sheet consists of ground calcium carbonate.

The average particle size of ground calcium carbonate based on the air permeation method according to JIS M-8511 is preferably 4.50 μm or more and 10.00 μm or less, more preferably 4.80 μm or more and 7.50 μm or less.

(2) Inner Layer The inner layer contains an inorganic substance powder and a thermoplastic resin.

(2-1) Inorganic Powder Blended in Inner Layer The inorganic powder blended in the inner layer is not particularly limited as long as it satisfies the above-described requirements regarding the inorganic powder contained in the laminated sheet.

From the viewpoint that the effects of the present invention are easily exhibited, in a preferred embodiment of the present invention, the particle size distribution of the inorganic substance powder in the inner layer satisfies any or all of the following requirements.
- The particle size distribution D60 of the inorganic substance powder is 6.1 µm or more and 9.2 µm or less.
- The particle size distribution D70 of the inorganic substance powder is 7.7 µm or more and 11.5 µm or less.
- The particle size distribution D80 of the inorganic substance powder is 10.0 µm or more and 14.1 µm or less.
- The particle size distribution D90 of the inorganic substance powder is 13.7 µm or more and 18.1 µm or less.
- The particle size distribution D97 of the inorganic substance powder is 19.1 µm or more and 24.5 µm or less.

(2-2) Thermoplastic Resin Blended in Inner Layer As the thermoplastic resin blended in the inner layer, any resin that can be normally blended in the resin sheet can be used. The thermoplastic resins blended in the inner layer may be used singly or in combination of two or more.

Examples of thermoplastic resins include polyolefin-based resins, polyester-based resins, polystyrene-based resins, and the like. Among these, polyolefin-based resins are preferred from the viewpoint of good moldability and the like.

In the present invention, "polyolefin-based resin" means a polyolefin-based resin having olefin component units as a main component.
The phrase “mainly composed of olefin component units” means that the olefin component unit is 50% by mass or more (preferably 75% by mass or more, more preferably 85% by mass or more, and still more preferably 90% by mass or more) in the polyolefin resin. meant to be included.
The method for producing the polyolefin resin used in the present invention is not particularly limited, and any method using a Ziegler-Natta catalyst, a metallocene catalyst, a radical initiator (oxygen, peroxide, etc.) or the like may be used. .

Polyolefin-based resins include, for example, polypropylene-based resins and polyethylene-based resins.
The thermoplastic resin preferably contains a polypropylene-based resin and/or a polyethylene-based resin from the viewpoint that the effects of the present invention are likely to be exhibited and a good appearance etc. are easily achieved, and the polypropylene-based resin and/or polyethylene It is more preferable to consist of a system resin.

(2-2-1) Polypropylene resin The polypropylene resin in the present invention has a propylene component unit of preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, and most preferably 80% by mass. It includes a resin of 10% by mass or more.

Polypropylene resins include polypropylene homopolymers (propylene homopolymers), copolymers of propylene and other α-olefins (those copolymerizable with propylene), and the like.
"Other α-olefins" include, for example, α-olefins having 4 to 10 carbon atoms (ethylene, 1-butene, isobutylene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3,4- dimethyl-1-butene, 1-heptene, 3-methyl-1-hexene, etc.).

Propylene homopolymers include linear or branched polypropylenes showing various stereoregularities (isotactic, syndiotactic, atactic, hemiisotactic, etc.).

The copolymer of propylene may be any of polypropylene random copolymer (random copolymer), polypropylene block copolymer (block copolymer), binary copolymer, terpolymer and the like. Specific examples include ethylene-propylene random copolymers, butene-1-propylene random copolymers, ethylene-butene-1-propylene random terpolymers, ethylene-propylene block copolymers, and the like.

Among the above polypropylene-based resins, resins containing polypropylene block polymers are preferable, and resins composed of polypropylene block polymers are more preferable.

(2-2-2) Polyethylene-based resin The polyethylene-based resin in the present invention has an ethylene component unit of preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, and most preferably 80% by mass. It includes a resin of 10% by mass or more.

Polyethylene-based resins include high-density polyethylene (HDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), linear low-density polyethylene (LLDPE), ethylene-vinyl acetate copolymer, ethylene-propylene copolymer. ethylene-propylene-butene 1-copolymer, ethylene-butene 1-copolymer, ethylene-hexene 1-copolymer, ethylene-4-methylpentene 1-copolymer, ethylene-octene 1-copolymer and the like.

As the polyethylene-based resin, a resin containing high-density polyethylene and/or linear low-density polyethylene is preferable, and a resin composed of high-density polyethylene and/or linear low-density polyethylene is more preferable.

The high-density polyethylene preferably has an MFR (190°C, 21.6 kg) according to JIS K 6922-1 (ISO1133) of 5 g/10 minutes or more and 15 g/10 minutes or less, and 7 g/10 minutes or more and 13 g/10 minutes. More preferred are:

The linear low-density polyethylene preferably has an MFR (190° C., 2.16 kg) according to JIS K 6922-1 (ISO1133) of 0.5 g/10 min or more and 1.5 g/10 min or less. More preferably, it is 7 g/10 minutes or more and 1.3 g/10 minutes or less.

In resins containing high-density polyethylene and linear low-density polyethylene, the mass ratio of both (high-density polyethylene:linear low-density polyethylene) is preferably 90:10 to 50:50, more preferably 92:8 to 50:50, more preferably 94:6 to 50:50.

(2-3) Other Components Blended in the Inner Layer The inner layer may contain other components other than the inorganic powder and the thermoplastic resin as long as the effects of the present invention are not impaired. can be

As the other components, any component that can be usually blended in the resin sheet can be employed.
Such ingredients include lubricants, dispersants, antistatic agents, antioxidants, heat stabilizers, ultraviolet absorbers, and the like.
The types and amounts of these components can be appropriately set according to the effects to be obtained.

A preferred embodiment of the present invention includes a laminated sheet in which the inner layer consists of calcium carbonate particles (more preferably heavy calcium carbonate particles) and a thermoplastic resin.

(2-4) Proportions of Ingredients Blended in Inner Layer The contents of the inorganic powder and thermoplastic resin blended in the inner layer are not particularly limited as long as they satisfy the above requirements regarding the inorganic powder contained in the laminated sheet.

From the viewpoint that the effects of the present invention are easily exhibited, it is preferable that the inner layer contains a sufficient amount of inorganic substance powder. It is 0% by mass or more, more preferably 45.0% by mass or more, and still more preferably 50.0% by mass or more.

From the viewpoint of imparting sufficient moldability to the laminated sheet, the upper limit of the content of the inorganic substance powder is preferably 80.0% by mass or less, more preferably 75.0% by mass or less, and even more preferably 75.0% by mass or less, relative to the inner layer. is 70.0% by mass or less.

The content of the inorganic substance powder in the inner layer may be a number specified by the following method. The numbers specified by the following method may overlap with the examples of the content of the inorganic substance powder in the inner layer given above.
(1) Process 1
First, an SEM image of the cross section of the laminated sheet is obtained at five arbitrary locations on the laminated sheet.
The total weight is also recorded for the laminated sheet.
Based on the SEM images obtained at five locations, the area occupied by the inorganic substance powder with respect to the entire cross section of the laminated sheet (area 1) and the area occupied by the inorganic substance powder with respect to the inner layer in the cross section of the laminated sheet (area 2) were determined. Identify.
(2) Process 2
The laminated sheet is then fired to obtain ash (dry powder).
Based on the obtained ash content, the type and mass of the inorganic powder are specified.
(3) Process 3
The content (% by mass) of the inorganic substance powder in the inner layer is specified based on the following formula.
Content of inorganic substance powder in the inner layer (% by mass) = “mass of inorganic substance powder” × “area 2/area 1” ÷ “laminated sheet total mass”

In step 1, the lower limit of "area 2/area 1" is preferably 0.7 or more, more preferably 1.0.

The content of the thermoplastic resin can be adjusted according to the content of the inorganic powder.
The lower limit of the content of the inorganic substance powder is preferably 20.0% by mass or more, more preferably 25.0% by mass or more, and still more preferably 30.0% by mass or more with respect to the inner layer.
The upper limit of the thermoplastic resin content is preferably 60.0% by mass or less, more preferably 55.0% by mass or less, and even more preferably 50.0% by mass or less with respect to the inner layer.

(3) Outer layer The outer layer is a pair of layers laminated on the two surfaces of the inner layer (that is, in the laminated sheet of the present invention, two outer layers are formed so as to sandwich the inner layer).
In the present invention, the pair of layers is called a first outer layer and a second outer layer.

The configurations of the first outer layer and the second outer layer may be the same or different. However, the first outer layer and the second outer layer each contain a thermoplastic resin.

Preferred embodiments of the present invention include embodiments in which the configurations (composition, thickness, shape, etc.) of the first outer layer and the second outer layer are all the same.

(3-1) Thermoplastic Resin Blended in Outer Layer As the thermoplastic resin blended in the outer layer, any resin that can be normally blended in the resin sheet can be used. The thermoplastic resin blended in the outer layer may be used singly or in combination of two or more.

As the thermoplastic resin compounded in the outer layer, resins similar to those listed in the section "Thermoplastic resin compounded in the inner layer" can be employed.
However, in the laminated sheet of the present invention, the thermoplastic resin blended in the outer layer and the thermoplastic resin blended in the inner layer may be the same or different.

Preferred aspects of the present invention include all of the following aspects.
(Mode 1) The thermoplastic resin blended in the outer layer and the thermoplastic resin blended in the inner layer are all the same. (Mode 2) The thermoplastic resin blended in the first outer layer and the second outer layer. Aspect (Aspect 3) in which the thermoplastic resin blended in and the thermoplastic resin blended in the inner layer are all different (Aspect 3) The thermoplastic resin blended in the first outer layer, the thermoplastic resin blended in the second outer layer, and an aspect in which only two of the thermoplastic resins blended in the inner layer are the same

The thermoplastic resins in the first outer layer and the second outer layer are preferably resins containing polypropylene-based resins and/or polyethylene-based resins, and more preferably resins including polypropylene-based resins and/or polyethylene-based resins.

The proportion of the thermoplastic resin blended in the outer layer is not particularly limited as long as the resin sheet can be molded.

The lower limit of the thermoplastic resin content is preferably 80.0% by mass or more, more preferably 90.0% by mass or more, and still more preferably 99.0% by mass or more, relative to the outer layer.

The upper limit of the content of the thermoplastic resin is preferably 100.0% by mass with respect to the outer layer.

(3-2) Other Components Blended in the Outer Layer The outer layer may or may not contain components other than the thermoplastic resin as long as the effects of the present invention are not impaired.

As the other components, any component that can be usually blended in the resin sheet can be adopted.
Examples of such components include the aforementioned inorganic substance powders, lubricants, dispersants, antistatic agents, antioxidants, heat stabilizers, ultraviolet absorbers, and the like.
The types and amounts of these components can be appropriately set according to the effects to be obtained.

When inorganic substance powder is blended in the outer layer, the ratio of the inorganic substance powder in the inner layer (that is, the ratio of the inorganic substance powder to the entire inner layer) is the ratio of the total amount of the inorganic substance powder in the first outer layer and the second outer layer ( That is, it is blended more than the ratio of the inorganic substance powder to the entirety of the first outer layer and the second outer layer).
By adjusting in this way, the amount of inorganic substance powder distributed in the vicinity of the outermost surface of the laminated sheet is reduced, the surface smoothness is more stabilized, and the laminated sheet with excellent appearance can be easily obtained.

Whether or not the proportion of the inorganic substance powder in the inner layer is greater than the proportion of the total amount of the inorganic substance powder in the first outer layer and the second outer layer can be identified based on the analysis of the SEM image of the cross section of the laminated sheet.
Specifically, in the cross-sectional image of the laminated sheet, if the area ratio of the inorganic substance powder in the inner layer is larger than the total area ratio of the inorganic substance powder in the first outer layer and the second outer layer, the inorganic substance in the inner layer It can be determined that the proportion of the powder is greater than the proportion of the total amount of the inorganic substance powder in the first outer layer and the second outer layer.

The ratio of the total content of the inorganic substance powder in the first outer layer and the second outer layer to the content of the inorganic substance powder in the inner layer (total content of the inorganic substance powder in the first outer layer and the second outer layer/ The content of the inorganic substance powder in the inner layer) should be less than 1.0, but the smaller the ratio, the easier it is to obtain the effects of the present invention.
In a most preferred embodiment, the first outer layer and the second outer layer are free of inorganic powder.

A preferred embodiment of the present invention includes a laminated sheet in which the outer layers are each made of a thermoplastic resin.

(4) Thickness of each layer of the laminated sheet, etc. In the laminated sheet of the present invention, the thickness ratio of the first outer layer and the second outer layer is 2.0% with respect to the total thickness of the laminated sheet. It is more than 20.0% or less. That is, in the laminated sheet of the present invention, the total thickness of the outer layers (the total thickness of the first outer layer and the second outer layer) is 4.0% or more and 40.0% of the total thickness of the laminated sheet. 0% or less.
In the laminated sheet of the present invention, even when the thickness of the outer layer is thinner than the thickness of the inner layer, the surface smoothness is hardly impaired.

The lower limit of the thickness ratio in the first outer layer and the second outer layer is 2.0% or more, preferably 2.5%, relative to the total thickness of the laminated sheet, from the viewpoint of easily obtaining a good appearance. % or more, more preferably 3.0% or more.

The upper limit of the thickness ratio between the first outer layer and the second outer layer is that even if the ratio is small, in the case of the present invention, the surface smoothness due to the inorganic substance powder contained in the inner layer is less likely to be impaired. They are respectively 20.0% or less, preferably 18.0% or less, more preferably 16.0% or less, and most preferably 10.0% or less, relative to the total thickness.

In the laminate sheet of the present invention, the thickness ratio of the inner layer is adjusted according to the thickness of the outer layer, and is 60.0% or more and 96.0% or less of the total thickness of the laminate sheet.

The lower limit of the thickness of each of the first outer layer and the second outer layer is preferably 5.0 μm or more, more preferably 10.0 μm or more, from the viewpoint of easily obtaining a good appearance.

The upper limit of the thickness of each of the first outer layer and the second outer layer is preferably 50.0 μm or less, and more preferably 45.0 μm or less, from the viewpoint of easily achieving good moldability.

The lower limit of the thickness of the inner layer is preferably 50.0 μm or more, more preferably 100.0 μm or more, from the viewpoint of easily obtaining good mechanical properties.

The upper limit of the thickness of the inner layer is preferably 950.0 μm or less, more preferably 900.0 μm or less, from the viewpoint of good moldability.

The lower limit of the total thickness of the laminated sheet is adjusted according to the thickness of the outer layer and the inner layer, preferably 100.0 μm or more, more preferably 150.0 μm or more.

The upper limit of the total thickness of the laminated sheet is adjusted according to the thickness of the outer layer and the inner layer, preferably 990.0 μm or less, more preferably 700.0 μm or less.

The density of the laminated sheet is not particularly limited.

The laminated sheet may be a three-layer sheet consisting of an inner layer, a first outer layer, and a second outer layer, or a sheet of four or more layers in which other layers are provided outside the outer layer (outermost layer). Also good.
Any layer (printed layer, etc.) may be selected as the other layer as long as the effect of the present invention is not impaired.
However, the laminated sheet is preferably a three-layer sheet consisting of an inner layer, a first outer layer, and a second outer layer, from the viewpoint of easily suppressing variations in surface smoothness.

(5) Method for producing laminated sheet The method for producing the laminated sheet of the present invention is not particularly limited, and conventionally known methods for producing multilayer sheets and laminates can be employed.

Examples of the method for producing the laminated sheet include the following methods.
・Method of laminating the inner layer and outer layer formed into a sheet with a calender roll ・Method of co-extrusion of the inner layer and the outer layer A method in which co-extrusion molding is performed in the same process A method by extrusion inflation method using multiple annular dies

The laminated sheet may be stretched as necessary.

(6) Uses of Laminated Sheet The laminated sheet of the present invention can be used for any application of ordinary resin sheets.

The laminated sheet of the present invention may be subjected to any molding method after its production. Such molding methods are not particularly limited, and include vacuum molding, air pressure molding, match mold molding, and the like.
Among these, vacuum forming is preferable from the viewpoint of ease of forming. Therefore, the laminate sheet of the present invention includes an embodiment that is a laminate sheet for vacuum forming.

Suitable applications of the laminated sheet of the present invention include materials for packaging containers.
Therefore, the present invention includes packaging containers, particularly food packaging containers, formed from the laminated sheet of the present invention.

Food packaging containers include arbitrary containers such as trays, cups, lids of various containers, and bags.

(7) Food Packaging Container The present invention includes a food packaging container comprising the laminated sheet of the present invention. A food packaging container according to a preferred embodiment satisfies all of the following requirements.
- A food packaging container comprising a laminated sheet of three or more layers, wherein the laminated sheet comprises at least an inner layer and a first outer layer and a second outer layer laminated on the surface of the inner layer.
- The inner layer contains an inorganic powder and a thermoplastic resin.
- A 1st outer layer and a 2nd outer layer each contain a thermoplastic resin.
- The content of the inorganic substance powder is 40.0% by mass or more and 80.0% by mass or less with respect to the food packaging container.
- The particle size distribution D60 of the inorganic substance powder is 6.1 µm or more and 9.2 µm or less.
- The particle size distribution D70 of the inorganic substance powder is 7.7 µm or more and 11.5 µm or less.
- The particle size distribution D80 of the inorganic substance powder is 10.0 µm or more and 14.1 µm or less.
- The particle size distribution D90 of the inorganic substance powder is 13.7 µm or more and 18.1 µm or less.
- The particle size distribution D97 of the inorganic substance powder is 19.1 µm or more and 24.5 µm or less.
- The content of the inorganic substance powder in the inner layer is greater than the total content of the inorganic substance powder in the first outer layer and the second outer layer.
- In at least part of the cross section of the food packaging container, the ratio of the thicknesses of the first outer layer and the second outer layer is 2.0% or more and 20.0% of the total thickness of the laminated sheet, respectively. It is below.

The present invention also includes a laminated sheet for producing the food packaging container by vacuum forming. Details of the laminated sheet are as described above.

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples.

<Preparation and Evaluation of Laminated Sheet>
A laminated sheet was produced by the following method and evaluated.

(1) Preparation of materials Materials for each layer were prepared as follows.

(inorganic substance powder)
In this test, only calcium carbonate particles (heavy calcium carbonate particles) were used as the inorganic powder.
In each example, calcium carbonate particles whose particle size distribution satisfies the "particle size distribution of calcium carbonate particles" in Table 1 were used. For each calcium carbonate particle, calcium carbonate particle products A to C having a particle size distribution (Dn) shown in Table 1 are blended at an appropriate ratio, and if necessary, filtered through a filter with a predetermined pore size, or the particle size distribution is extremely narrow. Calcium carbonate particles having a desired particle size distribution were prepared by adding calcium carbonate having a predetermined particle size.

In this example, the particle size distribution was specified by the following method (laser diffraction particle size distribution measurement).
(1) The content of each inorganic substance powder obtained as ash was measured.
(2) Each inorganic substance powder (0.01 g) and deionized water (9.99 g) were weighed out with an electronic balance to prepare a 0.1 wt % inorganic powder aqueous solution.
(3) The prepared aqueous solution was placed in an ultrasonic cleaner for 5 minutes to disperse the powder.
(4) The obtained dispersion was added little by little to the sample collection tank of the sample dispersion unit in the laser diffraction particle size analyzer, the scattering intensity was adjusted to 5 to 10%, and the particle size distribution was measured. . Each sample was measured three times.

The ash content of the inorganic substance powder was obtained by heating the laminated sheet at 500° C. for 1 hour using an electric furnace (“ELECTRIC FURNACE TMF-3100”, Tokyo Rikakikai Co., Ltd.).

The following equipment was used for measuring the particle size distribution.
Electronic balance: sefi IUY-200, AS ONE CORPORATION (NO.: D303200214)
Ultrasonic cleaner: ULTRASONIC CLEANER, AS ONE CORPORATION (Serial Number: 1517Y0693)
Laser diffraction particle size analyzer: Mastersizer 3000, Malvern Panalytical Ltd (Device ID: MAL1183380)

The content of calcium carbonate in each layer is the value shown in "Ca" in the table.
Products A to C do not satisfy all or part of the particle size distribution Dn in the present invention.

(Thermoplastic resin)
Polypropylene resin (PP): Polypropylene block copolymer (melting point 160°C)
Polyethylene resin (PE): a blend of HDPE and LLDPE (HDPE:LLDPE (mass ratio) = 70:30)
The MFR (190° C., 21.6 kg) according to JIS K 6922-1 (ISO1133) of the above HDPE is 7.5 g/10 minutes.
The MFR (190° C., 2.16 kg) according to JIS K 6922-1 (ISO1133) of the LLDPE is 0.8 g/10 minutes.

(2) Preparation of Laminated Sheet Using the materials shown in the table, a three-layered laminated sheet was prepared by the multi-layer T-die method.
The total thickness of the laminated sheet was set at 260 μm.
The thickness of the inner layer was set to 230 μm (approximately 88% of the total thickness of the laminated sheet).
An outer layer (a first outer layer and a second outer layer) was provided on both sides of the inner layer, and the thickness of each outer layer was set to 15 μm (about 6% of the total thickness of the laminated sheet).

(3) Evaluation of laminated sheet The surface smoothness of the laminated sheet and the surface smoothness of the container obtained from the laminated sheet were evaluated by the following methods. The results are shown in the "surface smoothness" section of the table.

[Evaluation method for surface smoothness-1 (laminated sheet)]
A laminate sheet having a width of 5 cm and a length of 100 m was produced by the multi-layer T-die method. The resulting laminated sheet was cut into 10 cm length increments to prepare 100 sheet pieces, and the surface of each sheet piece was measured for an arithmetic mean height in accordance with JIS B0601:2001, and measured according to the following criteria. evaluated.

[Evaluation criteria for surface smoothness-1 (laminated sheet)]
A: The standard deviation of the arithmetic mean height was less than 15%.
B: The standard deviation of the arithmetic mean height was 15% or more and less than 30%.
C: The standard deviation of the arithmetic mean height was 30% or more.

[Evaluation method for surface smoothness-2 (container)]
15 to 30 sheets each having little variation in shape were selected from the laminated sheets in each test group obtained above.
Next, each laminated sheet is preheated with a far-infrared heater, and then formed into a tray-shaped container with a bottom diameter of 50 mmφ, an opening diameter of 50 mmφ, a height of 30 mm, and a flange width of 5 mm using a vacuum forming machine. The arithmetic mean height was measured according to B0601:2001 and evaluated according to the following criteria.

[Evaluation criteria for surface smoothness-2 (container)]
A: The standard deviation of the arithmetic mean height was less than 15%.
B: The standard deviation of the arithmetic mean height was 15% or more and less than 30%.
C: The standard deviation of the arithmetic mean height was 30% or more.

As shown in the table, the laminated sheet satisfying the requirements of the present invention had suppressed variations in surface smoothness.

The same tendency as described above was also obtained when inorganic substance powders (such as talc) other than calcium carbonate particles were used.
However, it was considered that the present invention is of great significance in that stable surface smoothness can be achieved even with a material such as heavy calcium carbonate particles, which tends to impair the surface smoothness.

In the above examples, the amount of the inorganic powder contained in the inner layer and the amount of the thermoplastic resin are equal, but even if the amount of the inorganic powder is increased, the amount of the inorganic powder is within the range of 80.0% by mass or less with respect to the laminated sheet. , the same results as above were obtained.
In particular, even if the amount of the inorganic substance powder is as high as 80.0% by mass with respect to the laminated sheet, the same results as in "Example 1-1" above can be obtained as long as the requirements of the present invention are satisfied. It was a very surprising finding that

In the above examples, no component other than the thermoplastic resin was blended in the outer layer, but even if other components such as inorganic powder were blended, the effect tended not to be impaired. However, the effect of the present invention tended to be more likely to be exhibited as the content of components other than the thermoplastic resin contained in the outer layer was smaller.

If the ratio of the thicknesses of the first outer layer and the second outer layer is less than 2.0% with respect to the total thickness of the laminated sheet, the unevenness caused by the inorganic substance powder contained in the inner layer will cause lamination. It floats out on the outermost surface of the sheet and tends to impair the surface smoothness.
On the other hand, when the thickness ratios of the first outer layer and the second outer layer are each 20.0% or more of the total thickness of the laminated sheet, the surface smoothness is good, but the lamination The amount of thermoplastic resin contained in the entire sheet increased, resulting in a laminated sheet that is not preferable from the viewpoint of reducing the environmental load.

Claims (12)

A laminated sheet having three or more layers,
The laminated sheet comprises at least an inner layer and a first outer layer and a second outer layer laminated on the surface of the inner layer,
The inner layer contains an inorganic powder and a thermoplastic resin,
The first outer layer and the second outer layer each contain a thermoplastic resin,
The content of the inorganic substance powder is 40.0% by mass or more and 80.0% by mass or less with respect to the laminated sheet,
The particle size distribution D60 of the inorganic substance powder is 6.1 μm or more and 9.2 μm or less,
The particle size distribution D70 of the inorganic substance powder is 7.7 μm or more and 11.5 μm or less,
The particle size distribution D80 of the inorganic substance powder is 10.0 μm or more and 14.1 μm or less,
The particle size distribution D90 of the inorganic substance powder is 13.7 μm or more and 18.1 μm or less,
The particle size distribution D97 of the inorganic substance powder is 19.1 μm or more and 24.5 μm or less,
the proportion of the inorganic substance powder in the inner layer is higher than the proportion of the total amount of the inorganic substance powder in the first outer layer and the second outer layer;
The thickness ratios of the first outer layer and the second outer layer are respectively 2.0% or more and 20.0% or less with respect to the total thickness of the laminated sheet,
At least one of the thermoplastic resins in the inner layer, the first outer layer, and the second outer layer contains a polypropylene-based resin and/or a polyethylene-based resin,
The inorganic substance powder contains calcium carbonate particles,
Laminated sheet. The particle size distribution D60 of the inorganic substance powder is 6.1 μm or more and 8.2 μm or less,
The particle size distribution D70 of the inorganic substance powder is 7.7 μm or more and 9.8 μm or less,
The particle size distribution D80 of the inorganic substance powder is 10.0 μm or more and 12.0 μm or less,
The particle size distribution D90 of the inorganic substance powder is 13.7 μm or more and 15.6 μm or less,
The particle size distribution D97 of the inorganic substance powder is 19.1 μm or more and 21.4 μm or less.
The laminated sheet according to claim 1. The particle size distribution D60 of the inorganic substance powder is more than 6.5 μm and 8.0 μm or less,
The particle size distribution D70 of the inorganic substance powder is more than 7.9 μm and 9.8 μm or less,
The particle size distribution D80 of the inorganic substance powder is 10.0 μm or more and 12.0 μm or less,
The particle size distribution D90 of the inorganic substance powder is 13.7 μm or more and 15.6 μm or less,
The particle size distribution D97 of the inorganic substance powder is 19.1 μm or more and 21.4 μm or less.
The laminated sheet according to claim 1. 2. The laminated sheet according to claim 1, wherein the inorganic substance powder has a particle size distribution D99 of 23.3 [mu]m or more and 33.5 [mu]m or less. 2. The laminated sheet according to claim 1, wherein said polyethylene-based resin comprises high-density polyethylene and/or linear low-density polyethylene. 2. The laminate sheet according to claim 1, wherein the polypropylene-based resin comprises a polypropylene block polymer. 2. The laminate sheet of claim 1, wherein said calcium carbonate particles comprise ground calcium carbonate particles. 2. The method according to claim 1, wherein the thickness ratio of the first outer layer and the second outer layer is 2.0% or more and 10.0% or less with respect to the total thickness of the laminated sheet. Laminated sheet. The laminate sheet according to any one of claims 1 to 8, wherein the laminate sheet is a laminate sheet for vacuum forming. A food packaging container molded from the laminated sheet according to claim 9. A food packaging container made of laminated sheets of three or more layers,
The laminated sheet comprises at least an inner layer and a first outer layer and a second outer layer laminated on the surface of the inner layer,
The inner layer contains an inorganic powder and a thermoplastic resin,
The first outer layer and the second outer layer each contain a thermoplastic resin,
The content of the inorganic substance powder is 40.0% by mass or more and 80.0% by mass or less with respect to the food packaging container,
The particle size distribution D60 of the inorganic substance powder is 6.1 μm or more and 9.2 μm or less,
The particle size distribution D70 of the inorganic substance powder is 7.7 μm or more and 11.5 μm or less,
The particle size distribution D80 of the inorganic substance powder is 10.0 μm or more and 14.1 μm or less,
The particle size distribution D90 of the inorganic substance powder is 13.7 μm or more and 18.1 m or less,
The particle size distribution D97 of the inorganic substance powder is 19.1 μm or more and 24.5 μm or less,
the content of the inorganic substance powder in the inner layer is greater than the total content of the inorganic substance powder in the first outer layer and the second outer layer;
In at least a part of the cross section of the food packaging container, the ratio of the thicknesses of the first outer layer and the second outer layer to the total thickness of the laminated sheet is 2.0% or more. .0% or less,
At least one of the thermoplastic resins in the inner layer, the first outer layer, and the second outer layer contains a polypropylene-based resin and/or a polyethylene-based resin,
The inorganic substance powder contains calcium carbonate particles,
Food packaging container. A laminated sheet for producing the food packaging container of claim 11 by vacuum forming.