Sheet, laminated sheet, or food / drink packaging container

Abstract

To provide a technology for suppressing the generation of off-flavors in food / drink packaging containers filled highly with inorganic powder.SOLUTION: The present invention provides, e.g., a sheet composed of a single layer, or a sheet including a single-layer portion and an ink-receiving layer. The sheet is for forming a food / drink packaging container. The single layer or the single-layer portion includes a thermoplastic resin and inorganic powder. The content of the inorganic powder is 40.0 mass% or more and 80.0 mass% or less relative to the sheet. The inorganic powder includes calcium carbonate. The inorganic powder satisfies all of predetermined requirements.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a sheet, a laminated sheet, or a packaging container for food and drink.

Background Art

[0002] In recent years, from the viewpoint of reducing the environmental load, attempts have been made to highly fill resin molded products with inorganic substance powders (for example, Patent Document 1). Resin molded products highly filled with inorganic substance powders are generally superior in mechanical properties and the like compared to the resin alone.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the present inventor has found that, in a packaging container for food and drink highly filled with an inorganic substance powder, fine scratches are generated on the surface, and among the inorganic substance powders, calcium carbonate in particular can elute at the end of the container (a portion that is likely to come into contact with the mouth of the container user). The elution of calcium carbonate does not harm the safety of the living body. However, the present inventor has found that depending on the calcium carbonate used, it may cause an off-flavor in the food and drink placed in the container. When the food and drink are acidic, tasteless, or liquid materials (such as water, oil, emulsions, etc.), the off-flavor can become prominent.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a technique for suppressing the generation of off-flavors in a packaging container for food and drink highly filled with an inorganic substance powder.

Means for Solving the Problems

[0006] The inventors of the present invention have found that the above problems can be solved by blending an inorganic substance powder that satisfies predetermined requirements regarding the content of trace components in a packaging container for food and drink with a high filling of the inorganic substance powder, and have thus completed the present invention. More specifically, the present invention provides the following.

[0007] (1) A sheet composed of a single layer or a sheet including a single-layer portion and an ink-receiving layer, wherein the sheet is a sheet for forming a packaging container for food and drink, the single layer or the single-layer portion contains a thermoplastic resin and an inorganic substance powder, 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 sheet, the inorganic substance powder mainly contains calcium carbonate, the inorganic substance powder satisfies all of the following requirements: a sheet. (Requirement 1) The content of lead per 1 g of the inorganic substance powder is 20 μg or less. (Requirement 2) When the inorganic substance powder is 100% by mass, the total amount of alkali metals and magnesium is 1.0% by mass or less. (Requirement 3) When the inorganic substance powder is 100% by mass, the content of barium is 0.030% by mass or less.

[0008] (2) The sheet according to (1), wherein the inorganic substance powder further satisfies the following requirement: (Requirement 4) The content of arsenic per 1 g of the inorganic substance powder is 3 μg or less.

[0009] (3) The resin composition according to (1), wherein the content of calcium carbonate is 80% by mass or more with respect to the inorganic substance powder.

[0010] (4) The sheet according to (1), wherein the calcium carbonate includes heavy calcium carbonate.

[0011] (5) The sheet according to (4), wherein the heavy calcium carbonate contains heavy calcium carbonate having an average particle diameter of 0.7 μm or more and 6.0 μm or less by the air permeability method according to JIS M-8511:2014.

[0012] (6) The sheet according to (1), wherein the thermoplastic resin contains a polypropylene-based resin and / or a polyethylene-based resin.

[0013] (7) The sheet according to (6), wherein the polyethylene-based resin contains high-density polyethylene and / or linear low-density polyethylene.

[0014] (8) The sheet according to (6), wherein the polypropylene-based resin contains a polypropylene block polymer.

[0015] (9) The sheet according to any one of (1) to (8), wherein the sheet is for vacuum forming.

[0016] (10) A packaging container for food and drink formed from the sheet of (9).

[0017] (11) A laminated sheet having three or more layers, wherein the laminated sheet is a sheet for forming a packaging container for food and drink, the laminated sheet includes at least an inner layer, a first outer layer and a second outer layer laminated on the surface of the inner layer, 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, 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 ratio of the inorganic substance powder in the inner layer is larger than the total ratio of the inorganic substance powders in the first outer layer and the second outer layer, the ratio of the thickness of the first outer layer and the second outer layer is 2.0% or more and 20.0% or less with respect to the total thickness of the laminated sheet, respectively, the inorganic substance powder mainly contains calcium carbonate. The laminated sheet, wherein the inorganic substance powder satisfies all of the following requirements. (Requirement 1) The lead content per 1 g of the inorganic substance powder is 20 μg or less. (Requirement 2) When the inorganic substance powder is 100% by mass, the total amount of alkali metal and magnesium is 1.0% by mass or less. (Requirement 3) When the inorganic substance powder is 100% by mass, the barium content is 0.030% by mass or less.

[0018] (12) The laminated sheet according to (11), wherein the inorganic substance powder further satisfies the following requirement. (Requirement 4) The arsenic content per 1 g of the inorganic substance powder is 3 μg or less.

[0019] (13) The laminated sheet according to (11), wherein the calcium carbonate content is 80% by mass or more with respect to the inorganic substance powder.

[0020] (14) The laminated sheet according to (11), wherein the calcium carbonate contains heavy calcium carbonate.

[0021] (15) The laminated sheet according to (14), wherein the heavy calcium carbonate contains heavy calcium carbonate having an average particle diameter of 0.7 μm or more and 6.0 μm or less by the air permeability method according to JIS M-8511:2014.

[0022] (16) The laminated sheet according to (11), wherein at least one of the inner layer, the first outer layer, and the second outer layer contains a polypropylene-based resin and / or a polyethylene-based resin as the thermoplastic resin.

[0023] (17) The laminated sheet according to (16), wherein the polyethylene-based resin contains high-density polyethylene and / or linear low-density polyethylene.

[0024] (18) The laminated sheet according to (16), wherein the polypropylene-based resin contains a polypropylene block polymer.

[0025] (19) The ratio of the thickness 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, respectively, and the laminated sheet according to (11).

[0026] (20) The laminated sheet is for vacuum forming, and the laminated sheet according to any one of (10) to (19).

[0027] (21) A food and beverage packaging container formed from the laminated sheet of (20).

[0028] (22) A food and beverage packaging container comprising a laminated sheet of three or more layers, The laminated sheet includes an inner layer, a first outer layer and a second outer layer laminated on the surface of the inner layer, 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, 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 ratio of the inorganic substance powder in the inner layer is larger than the ratio of the total amount 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 and beverage packaging container, the ratio of the thickness of the first outer layer and the second outer layer is 2.0% or more and 20.0% or less with respect to the total thickness of the laminated sheet, respectively, The inorganic substance powder mainly contains calcium carbonate, The inorganic substance powder satisfies all of the following requirements, and a food and beverage packaging container. (Requirement 1) The lead content per 1 g of the inorganic substance powder is 20 μg or less. (Requirement 2) When the inorganic substance powder is 100% by mass, the total amount of alkali metal and magnesium is 1.0% by mass or less. (Requirement 3) When the inorganic substance powder is 100% by mass, the barium content is 0.030% by mass or less.

[0029] (23) A laminated sheet for producing a food and beverage packaging container of (22) by vacuum forming.

Effect of the Invention

[0030] According to the present invention, there is provided a technique for suppressing the generation of off-flavors in a food and beverage packaging container highly filled with an inorganic substance powder.

Mode for Carrying Out the Invention

[0031] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto.

[0032] <Single-layer sheet> The sheet according to an embodiment of the present invention is a single-layer sheet or a sheet including a single-layer portion and an ink-receiving layer, and can satisfy all of the following requirements. · The sheet is a sheet for forming a food and beverage packaging container. · The single layer or the single-layer portion contains a thermoplastic resin and an inorganic substance powder. · 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 sheet. · The inorganic substance powder mainly contains calcium carbonate. · The inorganic substance powder satisfies all of the following requirements. (Requirement 1) The lead content per 1 g of the inorganic substance powder is 20 μg or less. (Requirement 2) When the inorganic substance powder is 100% by mass, the total amount of alkali metals and magnesium is 1.0% by mass or less. (Requirement 3) When the inorganic substance powder is 100% by mass, the barium content is 0.030% by mass or less.

[0033] As a result of investigations by the present inventors, it has been found that when a food or beverage is placed in a food and beverage packaging container highly filled with an inorganic substance powder, calcium carbonate in particular can elute from the inorganic substance powder. Such elution is likely to be observed at fine scratches generated on the surface of the container or at the end of the container (a portion highly likely to come into contact with the mouth of the container user).

[0034] The elution of calcium carbonate does not harm the safety of the living body. However, the inventor has found that depending on the calcium carbonate used, there is a possibility of causing an off-flavor in the food or drink contained in the container. Such an off-flavor is presumed to be derived from trace impurities (such as lead and alkali metals) contained in the calcium carbonate. In addition, when the food or drink is an acidic food or drink (such as vinegar), a light-tasting food or drink, a liquid material (such as water, oil, emulsion, etc.), the off-flavor can become prominent.

[0035] In the present invention, "off-flavor" includes not only a sense of disharmony in taste but also abnormal odors such as metallic odor. The presence or absence and degree of off-flavor can be specified by the method shown in the examples.

[0036] In one embodiment of the present invention, "consisting of component A" means substantially not containing components other than component A. In one embodiment of the present invention, "substantially not containing component B" includes, for example, a mode of not containing component B at all.

[0037] In one embodiment of the present invention, "mainly containing component A" means that the content of component A is more than half with respect to the whole of the predetermined components. For example, "mainly containing component A" includes that the content of component A is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, even more preferably 99% by mass or more, and most preferably 100% by mass with respect to the whole of the predetermined components.

[0038] Hereinafter, the configuration of the sheet according to one embodiment of the present invention will be described in detail.

[0039] (1) Thermoplastic resin The thermoplastic resin constituting the sheet is not particularly limited, and a resin that can be usually blended in a resin molded product can be adopted. The thermoplastic resin may be used alone or in combination of two or more.

[0040] (1-1) Types of thermoplastic resins The thermoplastic resin is not particularly limited, but from the viewpoint of moldability and the like, polyolefin resins, polyester resins, polystyrene resins, and the like can be mentioned.

[0041] In one embodiment of the present invention, the thermoplastic resin preferably contains a polyolefin resin, and more preferably consists of a polyolefin resin. In one embodiment of the present invention, the "polyolefin resin" means a polyolefin resin having an olefin component unit as a main component. "Having an olefin component unit as a main component" means that the olefin component unit is contained in the polyolefin resin in an amount of 50% by mass or more (preferably 75% by mass or more, more preferably 85% by mass or more, still more preferably 90% by mass or more). The production method of the polyolefin resin used in the present invention is not particularly limited, and any method such as a method using a Ziegler-Natta catalyst, a metallocene catalyst, a radical initiator (oxygen, peroxide, etc.) can be used.

[0042] Examples of the polyolefin resin include polypropylene resins and polyethylene resins. From the viewpoint that the effects of the present invention are easily achieved and further, a good appearance and the like are easily realized, the thermoplastic resin preferably contains a polypropylene resin and / or a polyethylene resin, and more preferably consists of a polypropylene resin and / or a polyethylene resin.

[0043] (1-1-1) Polypropylene resins The polypropylene resin in the present invention includes resins in which the propylene component unit is 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 or more.

[0044] Examples of the polypropylene resin include polypropylene homopolymers (propylene homopolymers) and copolymers of propylene and other α-olefins (capable of copolymerizing with propylene). Examples of the "other α-olefins" include 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.).

[0045] The propylene homopolymer includes linear or branched polypropylene, etc., which exhibit various stereoregularities (isotactic, syndiotactic, atactic, hemi-isotactic, etc.).

[0046] The copolymer of propylene may be any of polypropylene random copolymer (random copolymer), polypropylene block copolymer (block copolymer), binary copolymer, ternary copolymer, etc. Specifically, ethylene-propylene random copolymer, 1-butene-propylene random copolymer, ethylene-1-butene-propylene random terpolymer, ethylene-propylene block copolymer, etc. are included.

[0047] Among the above polypropylene-based resins, a resin containing a polypropylene block polymer is preferred, and a resin composed of a polypropylene block polymer is more preferred.

[0048] (1-1-2) Polyethylene-based resin The polyethylene-based resin in the present invention includes resins in which the ethylene component unit is 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 or more.

[0049] Examples of the polyethylene-based resin 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.

[0050] 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.

[0051] The high-density polyethylene preferably has an MFR (190 °C, 21.6 kg) according to JIS K 6922-1:2018 (ISO1133) of 5 g / 10 min or more and 15 g / 10 min or less, and more preferably 7 g / 10 min or more and 13 g / 10 min or less.

[0052] The linear low-density polyethylene preferably has an MFR (190 °C, 2.16 kg) according to JIS K 6922-1:2018 (ISO1133) of 0.5 g / 10 min or more and 1.5 g / 10 min or less, and more preferably 0.7 g / 10 min or more and 1.3 g / 10 min or less.

[0053] In the resin containing high-density polyethylene and linear low-density polyethylene, the mass ratio of the two (high-density polyethylene: linear low-density polyethylene) is preferably 90:10 to 50:50, more preferably 92:8 to 50:50, and still more preferably 94:6 to 50:50.

[0054] (1-2) Blending amount of thermoplastic resin The content of the thermoplastic resin can be appropriately set according to the blending amount of the inorganic substance powder and the like.

[0055] From the viewpoint of moldability and the like, the content of the thermoplastic resin is preferably 10% by mass or more, more preferably 15% by mass or more, and still more preferably 20% by mass or more with respect to the sheet (preferably a single layer or a single-layer part).

[0056] From the viewpoint that a sufficient amount of the inorganic substance powder can be blended and good mechanical properties are easily exhibited, the content of the thermoplastic resin is preferably 50% by mass or less, more preferably 45% by mass or less, and still more preferably 40% by mass or less with respect to the sheet (preferably a single layer or a single-layer part).

[0057] (2) Inorganic substance powder Among the inorganic substance powders, calcium carbonate is a material with a low environmental load. However, as described above, when prepared as a molded product used for food and drink, there is a risk of generating an off-flavor. However, as described below, by adjusting the content of trace components in the entire inorganic substance powder used, the off-flavor can be suppressed.

[0058] The present invention includes not only an embodiment containing calcium carbonate and other inorganic substance powders as the inorganic substance powder, but also an embodiment containing only calcium carbonate.

[0059] From the viewpoint that the effects of the present invention are particularly easily exhibited, in one embodiment of the present invention, the inorganic substance powder consists of calcium carbonate. Therefore, in such an embodiment, in the following description, "inorganic substance powder" may be appropriately read as "calcium carbonate (preferably heavy calcium carbonate)".

[0060] (2-1) Types of inorganic substance powder The inorganic substance powder is not particularly limited except that it mainly contains calcium carbonate, and those contained in ordinary resin molded products and the like can be adopted. The inorganic substance powder may be used alone as one kind of substance or in combination of two or more kinds of substances.

[0061] (2-1-1) Calcium carbonate As the calcium carbonate, either heavy calcium carbonate or light calcium carbonate may be used, or a combination thereof may be used. "Heavy calcium carbonate" refers to calcium carbonate obtained by mechanically pulverizing (dry method, wet method, etc.) natural raw materials (such as limestone) having CaCO 3 as the main component. "Light calcium carbonate" refers to 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.

[0062] The difference between heavy calcium carbonate and light calcium carbonate can be specified, for example, from the roundness calculated based on the analysis of the SEM image. The roundness of heavy calcium carbonate is, for example, in the range of 0.50 or more and 0.95 or less. The roundness of light calcium carbonate is, for example, approximately 1.00.

[0063] In one embodiment of the present invention, "roundness" is a value represented by the following formula and is an index of the degree of irregularity of particles. The closer the roundness is to "1" (the maximum value), the closer the shape is to a perfect circle, and the lower the numerical value, the higher the degree of irregularity. "Roundness" = (projected area of particles) / (area of a circle having the same perimeter as the projected perimeter of the particles)

[0064] Due to its manufacturing method, the shape of heavy calcium carbonate is not constant. Despite its low cost, it can easily and stably impart good mechanical properties to resin molded products. Therefore, preferred embodiments of the present invention include embodiments in which the calcium carbonate contains heavy calcium carbonate or consists of heavy calcium carbonate.

[0065] (2-1-2) Inorganic substance powder other than calcium carbonate Examples of the inorganic substance powder other than calcium carbonate include the following. Carbonates, sulfates, silicates, phosphates, or borates of metals (such as titanium, magnesium, aluminum, iron, zinc, etc.); Oxides of metals (such as titanium, calcium, magnesium, aluminum, iron, zinc, etc.); Hydrates of the above salts or oxides, etc.

[0066] Examples of inorganic substance powders other than calcium carbonate include titanium oxide, magnesium carbonate, zinc 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, etc.

[0067] Among the above, from the viewpoint that the effects according to the present invention can be more stably improved, as the inorganic substance powder other than calcium carbonate, components that do not contain any of lead, barium, arsenic, alkali metals, and magnesium as constituent components are preferable. As such components, one or more of titanium oxide, zinc oxide, alumina, clay, talc, kaolin, aluminum hydroxide, aluminum silicate, calcium silicate, aluminum sulfate, calcium sulfate, barium sulfate, silica sand, carbon black, zeolite, molybdenum, diatomaceous earth, sericite, shirasu, calcium sulfite, bentonite, and graphite are preferable, and titanium oxide (TiO 2 ) is more preferable.

[0068] The inorganic substance powder may be synthetic or derived from natural minerals.

[0069] In the present invention, when two or more kinds of inorganic substance powders are included, the combination ratio thereof is not particularly limited except that it mainly contains calcium carbonate powder, and can be appropriately set according to the effects to be obtained, etc.

[0070] In one aspect of the present invention, when two or more kinds of inorganic substance powders are included, the combination preferably includes calcium carbonate and one or more other kinds of inorganic substance powders, more preferably a combination including calcium carbonate and titanium oxide, and still more preferably a combination consisting of calcium carbonate and titanium oxide.

[0071] In one aspect of the present invention, when calcium carbonate and one or more other kinds of inorganic substance powders are included, the lower limit value of the content of the inorganic substance powder other than calcium carbonate is preferably 0.1% by mass or more, more preferably 1% by mass or more, and still more preferably 5% by mass or more, based on the total amount of the inorganic substance powders. In one aspect of the present invention, when calcium carbonate and one or more other kinds of inorganic substance powders are included, the upper limit value of the content of the inorganic substance powder other than calcium carbonate is preferably 20% by mass or less, more preferably 10% by mass or less, based on the total amount of the inorganic substance powders.

[0072] Whether calcium carbonate is included in the inorganic substance powder in the resin composition and its content can be specified by firing the resin composition and performing ash analysis. The method of ash analysis can be applied mutatis mutandis to JIS K 7250-1:2006.

[0073] (2-2) Trace components in the inorganic substance powder As described above, the main technical feature of the present invention lies in using, as the inorganic substance powder, one having a content of trace components within a predetermined range. The reason why the strange smell when using the molded product obtained from the sheet is suppressed by adjusting these components is presumably that when calcium carbonate elutes, the strange smell caused by the trace components themselves released into the food or drink or the oral cavity along with it, or the deterioration (for example, oxidative deterioration) of the food or drink derived from the trace components can be suppressed.

[0074] (2-2-1) Lead In one embodiment of the present invention, the content of lead per 1 g of the inorganic substance powder is 20 μg or less. The lower the lead content, the easier it is to achieve the effects of the present invention, and it is preferably 10 μg or less, more preferably 3 μg or less per 1 g of the inorganic substance powder. The lower limit of the lead content is not particularly limited, but it is preferably 0.0 μg or more per 1 g of the inorganic substance powder.

[0075] (2-2-2) Alkali metals and magnesium In one embodiment of the present invention, when the inorganic substance powder is 100% by mass, the total amount of alkali metals and magnesium is 1.0% by mass or less. The lower the total amount of alkali metals and magnesium, the easier it is to achieve the effects of the present invention. When the inorganic substance powder is 100% by mass, it is preferably 0.8% by mass or less, more preferably 0.7% by mass or less. The lower limit of the total amount of alkali metals and magnesium is not particularly limited, but when the inorganic substance powder is 100% by mass, it is preferably 0.0% by mass or more.

[0076] (2-2-3) Barium In one embodiment of the present invention, when the inorganic substance powder is 100% by mass, the barium content is 0.030% by mass or less. The lower the barium content, the easier it is to achieve the effects of the present invention. When the inorganic substance powder is 100% by mass, it is preferably 0.020% by mass or less, more preferably 0.010% by mass or less. The lower limit of the barium content is not particularly limited, but when the inorganic substance powder is 100% by mass, it is preferably 0.0% by mass or more.

[0077] (2-2-4) Other trace components The content of other trace components is not particularly limited, but the higher the purity of the inorganic substance powder, the easier it is to achieve the effects of the present invention.

[0078] For example, when the arsenic content per 1 g of the inorganic substance powder is preferably 3 μg or less, more preferably 2 μg or less, the safety of the molded product obtained from the sheet of the present invention is likely to be enhanced.

[0079] (2-2-5) Method for Adjusting Content of Trace Components The method for adjusting the content of trace components is not particularly limited, and examples include the following. · Synthesis or collection of inorganic substance powder that satisfies the requirements of the present invention. · Blending of inorganic substance powder that does not satisfy any of the requirements of the present invention and inorganic substance powder that satisfies the requirements of the present invention. · Blending of inorganic substance powder that satisfies only one of the requirements of the present invention (for example, only the lead content) and inorganic substance powder that satisfies only another requirement of the present invention (for example, only the total amount of alkali metals and magnesium).

[0080] (2-2-6) Method for Measuring Trace Components The content of trace components contained in the inorganic substance powder is specified by the following method described in the 9th Edition of the Japanese Pharmacopoeia of Food Additives (Ministry of Health, Labour and Welfare, Consumer Affairs Agency). The amount of trace components specified by this method does not necessarily accurately include the trace components contained in the inorganic substance powder other than calcium carbonate powder in the inorganic substance powder. However, since calcium carbonate powder is the main component in the inorganic substance powder, it sufficiently reflects the properties of the entire inorganic substance powder.

[0081] Regarding the purity test of calcium carbonate, etc., the 9th Edition of the Japanese Pharmacopoeia of Food Additives (Ministry of Health, Labour and Welfare, Consumer Affairs Agency) has the following description (pages 748 - 749). “(3) Lead Pb: 3 μg / g or less as Pb (2.0 g, Method 5, comparison solution: 6.0 mL of lead standard solution, flame method) Add 20 mL of hydrochloric acid (1→4) to this product, cover with a watch glass, etc., and gently boil for 15 minutes. After cooling, add 30 mL of water to obtain a sample solution. If the sample does not dissolve, evaporate to dryness, add 20 mL of hydrochloric acid (1→4) to the residue, cover with a watch glass, etc., and gently boil for 5 minutes. After cooling, add 30 mL of water to obtain a sample solution. However, change the amount of ammonium hydrogen citrate solution (1→2) shown in Method 5 to 50 mL, use 1 mL of bromothymol blue test solution as the indicator, and add aqueous ammonia until the yellow color of the solution changes to yellow - green.” “(4) Alkali metals and magnesium: 1.0% or less” Weigh 1.0 g of this product, gradually add 30 mL of hydrochloric acid (1→10), dissolve it, boil to expel carbon dioxide. After cooling, neutralize with ammonia test solution, add 60 mL of ammonium oxalate monohydrate solution (1→25), and heat on a water bath for 1 hour. After cooling, add water to make 100 mL, stir well, filter, measure 50 mL of the filtrate, add 0.5 mL of sulfuric acid, evaporate to dryness, and then strongly heat at 600 °C until it becomes constant in weight, and measure its mass. “(5) Not more than 0.030% as barium Ba Weigh 1.0 g of this product, add 8 mL of hydrochloric acid (1→4), dissolve it, add water to make 20 mL, and use it as the test solution. To the test solution, add 2 g of sodium acetate trihydrate, 1 mL of acetic acid (1→20), and 0.5 mL of potassium chromate solution (1→20), and let it stand for 15 minutes. The turbidity of the solution shall not be stronger than the turbidity exhibited by the following comparison solution. The comparison solution is prepared by adding water to 0.30 mL of barium standard solution to make 20 mL, and using the solution prepared by operating in the same manner as the test solution hereinafter. “(6) Not more than 3 μg / g as arsenic As (0.50 g, standard color arsenic standard solution 3.0 mL, apparatus B) Weigh this product, moisten it with 1 mL of water, add 4 mL of hydrochloric acid (1→4), dissolve it, and use it as the test solution.

[0082] Regarding the purity test, etc. of titanium oxide (titanium dioxide), the 9th Edition of the Japanese Pharmacopoeia of Food Additives (Ministry of Health, Labour and Welfare, Consumer Affairs Agency) has the following description (pages 808 - 809). “(3) Not more than 10 μg / g as lead Pb (4.0 g, comparison solution lead standard solution 4.0 mL, flame method) Add 50 mL of hydrochloric acid (1→20) to this product, cover with a watch glass or the like, boil for 20 minutes, then centrifuge to precipitate the insoluble matter. Filter the supernatant, wash the used container and the residue three times with 10 mL of hot water, and filter using the same filter paper. Further, wash the used filter paper with 10 - 15 mL of hot water, and combine the washings with the filtrate. After cooling, add water to make 100 mL to obtain a sample solution. Measure 10 mL of the sample solution, add 1 / 4 volume of hydrochloric acid, gently heat and evaporate to dryness. Add a small amount of nitric acid (1→100) to the residue and warm. After cooling, add more nitric acid (1→100) to make exactly 10 mL to obtain a test solution. Separately, accurately measure a lead standard solution, add nitric acid (1→100) to make exactly 10 mL to obtain a comparison solution. “(4) Arsenic As: 1 μg / g or less (10 g, standard color, arsenic standard solution 3.0 mL, apparatus B) Weigh this product, place it in a 250 mL beaker, add 50 mL of hydrochloric acid (1→20), cover with a watch glass or the like, heat until boiling, and further boil gently for 15 minutes. Then centrifuge to precipitate the insoluble matter. Filter the supernatant, wash the used beaker and the residue three times with 10 mL portions of hot water, and filter using the same filter paper. Further, wash the used filter paper with 10 - 15 mL of hot water, and combine the washings with the filtrate. After cooling, add water to make 100 mL to obtain a sample solution. Measure 15 mL of the sample solution to obtain a test solution.”

[0083] (2 - 3) Other conditions for the inorganic substance powder The inorganic substance powder can be in any form as long as it satisfies the above conditions for trace components.

[0084] The average particle size of the inorganic substance powder can be appropriately set according to the moldability to be achieved, etc. However, from the viewpoint of easily achieving stable dispersibility and easily exhibiting homogeneous mechanical properties throughout the resin molded product, the average particle size of the inorganic substance powder by the air permeability method according to JIS M - 8511:2014 is preferably 0.7 μm or more and 6.0 μm or less, more preferably 1.0 μm or more and 5.5 μm or less. The average particle size of the inorganic substance powder only needs to satisfy the above requirements for the entire inorganic substance powder.

[0085] In order to enhance the dispersibility and reactivity of the inorganic substance powder, the surface of the inorganic substance powder may or may not be surface-modified in advance according to a conventional method. Examples of the surface modification method include physical treatment methods (such as plasma treatment) and chemical treatment methods (methods using coupling agents or surfactants).

[0086] The shape of the inorganic substance powder is not particularly limited and may be any of particulate (spherical, irregular, etc.), flaky, granular, fibrous, etc.

[0087] (2-4) Blending amount of inorganic substance powder In one aspect of the present invention, the content of the inorganic substance powder is not particularly limited as long as the content of the inorganic substance powder with respect to the sheet (preferably the single-layer part) is 40.0% by mass or more and 80.0% by mass or less.

[0088] From the viewpoint of blending a sufficient amount of the inorganic substance powder, the lower limit of the content of the inorganic substance powder is 50.0% by mass or more, preferably 52.0% by mass or more, more preferably 54.0% by mass or more, and still more preferably 56.0% by mass or more with respect to the sheet (preferably the single-layer part).

[0089] From the viewpoint of moldability and the like, the upper limit of the content of the inorganic substance powder is 90.0% by mass or less, preferably 85.0% by mass or less, more preferably 80.0% by mass or less, and still more preferably 75.0% by mass or less with respect to the sheet (preferably the single-layer part).

[0090] From the viewpoint that even when the content of calcium carbonate in the inorganic substance powder is large, it can suppress off-flavors well, the content of calcium carbonate in the entire inorganic substance powder is preferably 70.0% by mass or more, more preferably 80.0% by mass or more, and most preferably 100.0% by mass.

[0091] Whether the inorganic substance powder contains calcium carbonate and its content can be specified by firing the resin molded product and performing ash analysis.

[0092] (3) Other components In the single layer or single layer portion of the sheet, other components other than the inorganic substance powder and the thermoplastic resin may or may not be blended within a range that does not inhibit the effects of the present invention.

[0093] As the other components, any components that can be normally blended in a resin molded product can be adopted. Examples of such components include colorants, 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 and the like.

[0094] In a preferred embodiment of the present invention, the single layer or single layer portion of the sheet includes those composed only of a thermoplastic resin and an inorganic substance powder.

[0095] (4) Ratio of thermoplastic resin to inorganic substance powder In the sheet (preferably a single layer or single layer portion), the mass ratio of the thermoplastic resin to the inorganic substance powder (thermoplastic resin: inorganic substance powder) is preferably 50:50 to 20:80, more preferably 45:55 to 20:80, and still more preferably 40:60 to 25:75. In this way, by making the ratio of the inorganic substance powder to the thermoplastic resin equal to or more than the same, it becomes easier to exhibit the effect of suppressing off-flavors by the inorganic substance powder.

[0096] (5) Method for manufacturing the sheet The method for manufacturing the sheet is not particularly limited, and any method known as a method for manufacturing a resin sheet can be adopted.

[0097] For example, the constituent components of the sheet may be pelletized (resin composition) and then formed into a sheet, or the constituent components of the sheet may be melt-kneaded and directly formed into a sheet.

[0098] The sheet may be subjected to any processing (such as stretching) as necessary.

[0099] The size and thickness of the sheet are not particularly limited. However, from the viewpoint of formability and the like, the thickness is usually 50 to 500 μm.

[0100] When the sheet is a single-layer sheet, the sheet contains a thermoplastic resin and an inorganic substance powder, and preferably consists of a thermoplastic resin and an inorganic substance powder.

[0101] When the sheet is a sheet having a single-layer portion and an ink-receiving layer, the sheet usually has a configuration in which an ink-receiving layer is formed on a part or all of the surface of the single layer.

[0102] In the present invention, the "ink-receiving layer" includes any configuration adopted in the field of printing paper, and includes, for example, a coating layer for fixing the ink applied by printing without bleeding. The printing method is not particularly limited, and examples thereof include inkjet printing. The type of the coating layer is not particularly limited, and includes a swelling type, a matte type, and the like.

[0103] The ink-receiving layer can be provided by applying and drying an ink-receiving layer coating liquid on the surface of the single-layer portion using a coating device (such as a gravure coater or a bar coater).

[0104] Among the sheets of the present invention, the sheet having a single-layer portion and an ink-receiving layer is suitable as a sheet to be subjected to a printing process on the surface.

[0105] (6) Use of the sheet In one aspect of the present invention, the sheet is used for forming a packaging container for food and drink.

[0106] In the present invention, the "packaging container for food and drink" includes any container for holding food and drink when the user of the container ingests food and drink.

[0107] According to the present invention, even for a container for containing food or drink that is likely to cause elution of calcium carbonate or food or drink that is likely to have an off-flavor, the off-flavor can be favorably suppressed. Examples of such food or drink include acidic food or drink (such as vinegar), food or drink with a light taste, and liquid materials (such as water, oil, and emulsions).

[0108] The size, shape, etc. of the packaging container for food or drink are not particularly limited.

[0109] Examples of the packaging container for food or drink include a plate, a tray, a Tupperware, a saucer, a cup, a bottle, etc.

[0110] The molding method for obtaining a molded product from the sheet is not particularly limited. Examples of the molding method include vacuum molding, pressure-air molding, hot press molding, etc. Among these, vacuum molding is mentioned as a preferable molding method.

[0111] The present invention also includes a packaging container for food or drink molded from the sheet of the present invention.

[0112] <Laminated Sheet> The sheet according to an embodiment of the present invention is a laminated sheet of three or more layers and can satisfy all of the following requirements. · The laminated sheet is a sheet for molding a packaging container for food or drink. · The laminated sheet includes at least an inner layer, a first outer layer and a second outer layer laminated on the surface of the inner layer. · 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. · 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 ratio of the inorganic substance powder in the inner layer is larger than the ratio of the total amount of the inorganic substance powder in the first outer layer and the second outer layer. · The ratio of the thickness of the first outer layer and the second outer layer is 2.0% or more and 20.0% or less with respect to the total thickness of the laminated sheet, respectively. · The inorganic substance powder mainly contains calcium carbonate. · The inorganic substance powder satisfies all of the following requirements. (Requirement 1) The lead content per 1 g of the inorganic substance powder is 20 μg or less. (Requirement 2) When the inorganic substance powder is 100% by mass, the total amount of alkali metals and magnesium is 1.0% by mass or less. (Requirement 3) When the inorganic substance powder is 100% by mass, the barium content is 0.030% by mass or less.

[0113] The laminated sheet of the present invention can also be said to be a sheet having outer layers provided on both sides of the sheet composed of the above-mentioned single layer. In other words, the above-mentioned single layer can have the same configuration as the inner layer of the laminated sheet.

[0114] Whether the laminated sheet satisfies the requirements of the present invention can be specified based on a scanning electron microscope (SEM) image. Specifically, by analyzing an SEM image of the cross-section of the laminated sheet or the like, the thickness of each layer and the content of the components contained in each layer can be specified.

[0115] (1) Overall configuration of the laminated sheet In one aspect of the present invention, the laminated sheet contains at least an inorganic substance powder and a thermoplastic resin, and preferably consists of an inorganic substance powder and a thermoplastic resin.

[0116] The present invention includes not only an aspect in which the inorganic substance powder contains calcium carbonate and other inorganic substance powders, but also an aspect in which only calcium carbonate is contained.

[0117] From the viewpoint that the effects of the present invention are particularly likely to be exhibited, in one aspect of the present invention, the inorganic substance powder consists of calcium carbonate. Therefore, in such an aspect, in the following description, "inorganic substance powder" may be appropriately read as "calcium carbonate (preferably heavy calcium carbonate)".

[0118] (1-1) Components incorporated in the laminated sheet The inorganic substance powder and the thermoplastic resin incorporated in the laminated sheet can adopt the configurations listed in the section of the <single-layer sheet>.

[0119] In one aspect of the present invention, 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. A molded article obtained from a laminated sheet having such a high content of the inorganic substance powder may have an unpleasant odor. However, in the present invention, as described above, such an unpleasant odor can be suppressed by adjusting the content of trace components contained in the inorganic substance powder.

[0120] From the viewpoint of blending a sufficient amount of the inorganic substance powder, the content of the inorganic substance powder is 40.0% by mass or more, preferably 45.0% by mass or more, more preferably 50.0% by mass or more with respect to the laminated sheet.

[0121] From the viewpoint of moldability and the like, the content of the inorganic substance powder is 80.0% by mass or less, preferably 75.0% by mass or less, more preferably 70.0% by mass or less with respect to the laminated sheet.

[0122] The content of the thermoplastic resin can be appropriately set according to the content of the inorganic substance powder and the like, and its lower limit is preferably 25.0% by mass or more, more preferably 30.0% by mass or more with respect to the laminated sheet. Also, its upper limit is preferably 55.0% by mass or less, more preferably 50.0% by mass or less with respect to the laminated sheet.

[0123] (1-2) Layer thickness of the laminated sheet, etc. In one aspect of the present invention, the ratio of the thickness of the first outer layer and the second outer layer is 2.0% or more and 20.0% or less with respect to the total thickness of the laminated sheet. That is, in such an aspect, the total thickness of the outer layer (the total value of the thicknesses of the first outer layer and the second outer layer) is 4.0% or more and 40.0% or less with respect to the total thickness of the laminated sheet.

[0124] The lower limit of the thickness ratio in the first outer layer and the second outer layer is preferably 2.0% or more, more preferably 2.5% or more, still more preferably 3.0% or more, respectively, based on the total thickness of the laminated sheet, from the viewpoint that the masking effect of off-flavors is likely to be good without excessively restricting the calcium carbonate content or the calcium carbonate requirements.

[0125] The upper limit of the thickness ratio in the first outer layer and the second outer layer is preferably 20.0% or less, more preferably 18.0% or less, still more preferably 16.0% or less, most preferably 10.0% or less, respectively, based on the total thickness of the laminated sheet, from the viewpoint that the off-flavor suppressing effect is achieved even if a scratch occurs and the inner layer is exposed.

[0126] In the laminated sheet of the present invention, the thickness ratio of the inner layer can be 60.0% or more and 96.0% or less based on the total thickness of the laminated sheet, and is adjusted according to the thickness of the outer layer.

[0127] The lower limit of the thickness in the first outer layer and the second outer layer is preferably 5.0 μm or more, more preferably 10.0 μm or more, respectively, from the viewpoint that the masking effect of off-flavors is likely to be good without excessively restricting the calcium carbonate content or the calcium carbonate requirements.

[0128] The upper limit of the thickness in the first outer layer and the second outer layer is preferably 50.0 μm or less, more preferably 45.0 μm or less, respectively, from the viewpoint of easily realizing good moldability and the like.

[0129] 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 that the off-flavor suppressing effect is likely to be achieved even if it is thick.

[0130] 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 and the like.

[0131] 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.

[0132] 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.

[0133] The density of the laminated sheet is not particularly limited.

[0134] The laminated sheet may be a three-layer sheet composed of an inner layer, a first outer layer, and a second outer layer, or may be a four-layer or more sheet having other layers provided on the outside (outermost layer) of the outer layer. As the other layers, any layer (such as a printing layer) can be selected as long as it does not inhibit the effects of the present invention. However, one aspect of the present invention includes an aspect in which the laminated sheet is a three-layer sheet composed of an inner layer, a first outer layer, and a second outer layer.

[0135] (2) Inner layer The inner layer contains an inorganic substance powder and a thermoplastic resin.

[0136] (2-1) Types of components incorporated into the inner layer The inorganic substance powder and the thermoplastic resin incorporated into the inner layer can adopt the configurations described in the section of <single-layer sheet>.

[0137] In the inner layer, other components other than the inorganic substance powder and the thermoplastic resin may or may not be incorporated as long as they do not inhibit the effects of the present invention.

[0138] As other components, any components that can be normally incorporated into a resin sheet can be adopted. Examples of such components include lubricants, dispersants, antistatic agents, antioxidants, heat stabilizers, ultraviolet absorbers, etc. The types and amounts of these components can be appropriately set according to the effects to be obtained, etc.

[0139] A preferred embodiment of the present invention includes a laminated sheet in which the inner layer is composed of only an inorganic substance powder (preferably only calcium carbonate) and only a thermoplastic resin.

[0140] (2-2) Ratio of components blended in the inner layer The content of the inorganic substance powder and the thermoplastic resin blended in the inner layer is not particularly limited as long as the above-mentioned requirements regarding the inorganic substance powder contained in the laminated sheet are satisfied. However, when an inorganic substance powder is blended in the outer layer described later, 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.

[0141] From the viewpoint that the effects of the present invention are easily achieved, it is preferable that a sufficient amount of the inorganic substance powder is contained in the inner layer. Therefore, the lower limit of the content of the inorganic substance powder is preferably 40.0% by mass or more, more preferably 45.0% by mass or more, and still more preferably 50.0% by mass or more with respect to the inner layer.

[0142] 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 still more preferably 70.0% by mass or less with respect to the inner layer.

[0143] The content of the inorganic substance powder in the inner layer can be a number specified by the following method. The number specified by the following method may overlap with the examples of the content of the inorganic substance powder with respect to the inner layer mentioned above. (1) Step 1 First, SEM images of the cross-section of the laminated sheet are obtained at five arbitrary locations of the laminated sheet. The total mass of the laminated sheet is also recorded. Based on the five obtained SEM images, the occupied area of the inorganic substance powder with respect to the entire cross-section of the laminated sheet (area 1) and the occupied area of the inorganic substance powder with respect to the inner layer in the cross-section of the laminated sheet (area 2) are specified. (2) Step 2 Next, the laminated sheet is fired to obtain an ash (dry powder). Based on the obtained ash content, identify the type and mass of the inorganic substance powder. (3) Step 3 Based on the following formula, identify the content (mass %) of the inorganic substance powder in the inner layer. Content (mass %) of the inorganic substance powder in the inner layer = "Mass of the inorganic substance powder" × "Area 2 / Area 1" ÷ "Total mass of the laminated sheet"

[0144] In Step 1, the lower limit of "Area 2 / Area 1" is preferably 0.7 or more, more preferably 1.0.

[0145] The content of the thermoplastic resin can be adjusted according to the content of the inorganic substance powder. The lower limit of the content of the inorganic substance powder is preferably 20.0 mass % or more, more preferably 25.0 mass % or more, and still more preferably 30.0 mass % or more for the inner layer. The upper limit of the content of the thermoplastic resin is preferably 60.0 mass % or less, more preferably 55.0 mass % or less, and still more preferably 50.0 mass % or less for the inner layer.

[0146] (3) Outer layer The outer layer is a pair of layers laminated on two surfaces of the inner layer (that is, in the laminated sheet of the present invention, two layers of the outer layer are formed so as to sandwich the inner layer). In the present invention, the pair of layers are referred to as the first outer layer and the second outer layer.

[0147] 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 at least a thermoplastic resin.

[0148] 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.

[0149] (3-1) Thermoplastic resin compounded in the outer layer As the thermoplastic resin compounded in the outer layer, the configurations listed in the section of <Single-layer sheet> above can be adopted.

[0150] In the laminated sheet of the present invention, the thermoplastic resin compounded in the outer layer and the thermoplastic resin compounded in the inner layer may be the same or different.

[0151] Preferred embodiments of the present invention include all of the following embodiments. (Embodiment 1) An embodiment in which all of the thermoplastic resin compounded in the outer layer and the thermoplastic resin compounded in the inner layer are the same (Embodiment 2) An embodiment in which the thermoplastic resin compounded in the first outer layer, the thermoplastic resin compounded in the second outer layer, and the thermoplastic resin compounded in the inner layer are all different (Embodiment 3) An embodiment in which only two of the thermoplastic resin compounded in the first outer layer, the thermoplastic resin compounded in the second outer layer, and the thermoplastic resin compounded in the inner layer are the same

[0152] (3-2) Other components compounded in the outer layer In the outer layer, other components other than the thermoplastic resin may or may not be compounded within a range that does not inhibit the effects of the present invention.

[0153] As the other components, any components that can be usually compounded in the resin sheet can be adopted. Examples of such components include the above-mentioned inorganic substance powder, lubricant, dispersant, antistatic agent, antioxidant, heat stabilizer, ultraviolet absorber, etc. The types and amounts of these components can be appropriately set according to the effects to be obtained and the like.

[0154] (3-3) Ratio of components compounded in the outer layer The content of the thermoplastic resin and the like compounded in the outer layer is not particularly limited as long as the requirements for the entire laminated sheet described above are satisfied.

[0155] The ratio of the thermoplastic resin compounded in the outer layer is not particularly limited as long as the resin sheet can be formed.

[0156] The lower limit of the content of the thermoplastic resin 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 with respect to the outer layer.

[0157] The upper limit of the content of the thermoplastic resin is preferably 100.0% by mass with respect to the outer layer.

[0158] When an inorganic substance powder is blended in the outer layer, the proportion of the inorganic substance powder in the inner layer (that is, the proportion of the inorganic substance powder with respect to the entire inner layer) is blended more than the proportion of the total amount of the inorganic substance powder in the first outer layer and the second outer layer (that is, the proportion of the inorganic substance powder with respect to the entirety of the first outer layer and the second outer layer). By adjusting in this way, even if calcium carbonate elutes, off-flavors can be more effectively suppressed.

[0159] Whether the proportion of the inorganic substance powder in the inner layer is more than the proportion of the total amount of the inorganic substance powder in the first outer layer and the second outer layer can be specified 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 occupied by the inorganic substance powder in the inner layer is more than the sum of the area ratios of the inorganic substance powder in the first outer layer and the second outer layer, it can be determined that the proportion of the inorganic substance powder in the inner layer is more than the proportion of the total amount of the inorganic substance powder in the first outer layer and the second outer layer.

[0160] The ratio of the total amount of the 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 amount of the content of the inorganic substance powder in the first outer layer and the second outer layer / content of the inorganic substance powder in the inner layer) may be less than 1.0, but the smaller the ratio, the easier it is to obtain the effect of the present invention. In the most preferred embodiment, the first outer layer and the second outer layer do not contain an inorganic substance powder.

[0161] A preferred embodiment of the present invention includes a laminated sheet in which the outer layer is composed only of a thermoplastic resin.

[0162] (4) Method for manufacturing a laminated sheet The manufacturing method of the laminated sheet is not particularly limited, and conventionally known manufacturing methods for multilayer sheets and laminates can be adopted.

[0163] Examples of the manufacturing method of the laminated sheet include the following methods. · A method of laminating an inner layer and an outer layer formed into a sheet shape with a calender roll · A method of co-extruding an inner layer and an outer layer · A method of performing melt-kneading of the raw material for the inner layer and co-extrusion molding of the inner and outer layers in the same process using a multi-layer T-die type twin-screw extruder · A method by an extrusion inflation method using a plurality of annular dies

[0164] The laminated sheet may be stretched if necessary.

[0165] (5) Use of the laminated sheet In one aspect of the present invention, the sheet is used for forming a packaging container for food and drink. Regarding the packaging container for food and drink and its molding, the configurations described in the section of <single-layer sheet> above can be adopted.

[0166] The present invention also includes a packaging container for food and drink formed from the laminated sheet of the present invention.

[0167] <Packaging container for food and drink> The present invention also includes the following packaging containers for food and drink. A packaging container for food and drink composed of a laminated sheet of three or more layers, The laminated sheet includes at least an inner layer, a first outer layer and a second outer layer laminated on the surface of the inner layer, 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, The content of the inorganic substance powder is 40.0 mass% or more and 80.0 mass% or less with respect to the laminated sheet, The ratio of the inorganic substance powder in the inner layer is larger than the ratio of the total amount 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 and drink packaging container, the ratio of the thicknesses of the first outer layer and the second outer layer is respectively 2.0% or more and 20.0% or less with respect to the total thickness of the laminated sheet. The inorganic substance powder mainly contains calcium carbonate. A food and drink packaging container in which the inorganic substance powder satisfies all of the following requirements. (Requirement 1) The lead content per 1 g of the inorganic substance powder is 20 μg or less. (Requirement 2) When the inorganic substance powder is 100% by mass, the total amount of alkali metals and magnesium is 1.0% by mass or less. (Requirement 3) When the inorganic substance powder is 100% by mass, the barium content is 0.030% by mass or less.

[0168] For the details of each component of the food and drink packaging container of the present invention, the components listed in the above <single-layer sheet> and <laminated sheet> sections can be adopted.

[0169] The present invention also includes a laminated sheet for producing the above food and drink packaging container by vacuum forming.

Examples

[0170] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0171] <Production and Evaluation of Sheets and Food and Drink Packaging Containers> Sheets (single-layer sheets or three-layer laminated sheets) were produced by the following method. Food and drink packaging containers were produced from the sheets and evaluated.

[0172] (1) Preparation of Materials The materials for each layer were prepared as follows.

[0173] (1-1) Inorganic Substance Powder The following were prepared as the inorganic substance powder. · Calcium carbonate particles (heavy calcium carbonate particles): The average particle diameter by the air permeability method according to JIS M-8511:2014 for these calcium carbonate particles was 2.0 μm. · Titanium oxide particles: The average particle diameter by the air permeability method according to JIS M-8511:2014 for these titanium oxide particles was 0.6 μm.

[0174] Only calcium carbonate particles were used to prepare the following "inorganic powders 1" to "inorganic powders 6". First, three types with different trace component contents (calcium carbonate purity) recovered from different mines were blended in various ratios to prepare inorganic powders 1 to 6 (Table 1). These inorganic powders 1 to 6 were used in the amounts shown in Tables 2 to 5. The trace component content in the calcium carbonate particles was measured in accordance with the section on "Calcium Carbonate" (pages 748 - 749) of the 9th Edition of the Japanese Pharmacopoeia (Ministry of Health, Labour and Welfare, Consumer Affairs Agency). This pharmacopoeia stipulates the measurement methods for trace components (lead, alkali metals and magnesium, hydrochloric acid-insoluble substances, and free alkali, etc.) contained in calcium carbonate.

[0175] Furthermore, using calcium carbonate particles and titanium oxide particles, the following "inorganic powder 7" was prepared. The purchased titanium oxide particles and calcium carbonate particles were blended at a mass ratio of titanium oxide particles:calcium carbonate particles = 10:90 to prepare "inorganic powder 7". As the calcium carbonate particles, "inorganic powder 1" was used. The trace component content in the titanium oxide particles was measured in advance in accordance with the section on "Calcium Carbonate" (pages 748 - 749) of the 9th Edition of the Japanese Pharmacopoeia (Ministry of Health, Labour and Welfare, Consumer Affairs Agency). As a result, the trace components contained in titanium dioxide were all below the detection limit. Therefore, the amount of trace components contained in the inorganic substance powder used in this example is the same as the amount of trace components contained in the calcium carbonate powder.

[0176] In Table 1, each trace component content means the following. · Lead: The content of lead per gram of inorganic substance powder (unit: μg) · Alkali metal: Total amount of alkali metal and magnesium (unit: mass %) when the inorganic substance powder is 100 mass % · Barium: Content of barium (unit: mass %) when the inorganic substance powder is 100 mass % · Arsenic: Content of arsenic per 1 gram of inorganic substance powder (unit: μg)

[0177]

Table 1

[0178] (1-2) Thermoplastic resin One of the following thermoplastic resins was used. Polypropylene-based resin (PP): Polypropylene block copolymer (melting point 160 °C) Polyethylene-based resin (PE): Blend of HDPE and LLDPE (HDPE:LLDPE (mass ratio) = 70:30) Note that for the above HDPE, the MFR (190 °C, 21.6 kg) according to JIS K 6922-1:2018 (ISO1133) is 7.5 g / 10 min. For the above LLDPE, the MFR (190 °C, 2.16 kg) according to JIS K 6922-1:2018 (ISO1133) is 0.8 g / 10 min.

[0179] (2) Production of sheet A sheet (a sheet consisting only of a single layer part) was produced by the T-die method using the thermoplastic resin and the inorganic substance powder at the ratios shown in Tables 2 to 5. In addition, a laminated sheet having an outer layer (made of a polypropylene-based resin or a polyethylene-based resin) on both sides of the single layer was also produced.

[0180] (3) Production of food and drink packaging containers Using the sheet obtained in (2) above, a wide-mouth bottle-shaped molded product (length 150 mm × diameter 120 mm × thickness 2 mm) was obtained by vacuum forming. Next, using a scraper, the entire inner surface of the molded product was gently scratched to prepare samples with fine scratches as well. Note that the mouth part of each molded product has a state where the sheet cross-section is exposed.

[0181] (4) Sensory test - 1 (beverage) Drinking vinegar (pH = 2.7) was poured into each molded product (with or without scratches). After a part of it was poured out from the mouth part, a lid was placed on the mouth part and stored at room temperature for one week. By this operation, the mouth part of the molded product was in a state where drinking vinegar adhered. Next, 20 panelists were made to take a sip of the drinking vinegar poured from the molded product into a clean glass cup, and the presence or absence and degree of off-flavor were evaluated according to the following criteria. The results are shown in the "Off-flavor" items in Tables 2 to 5. For example, "Off-flavor (beverage, no scratch)" indicates the result regarding the off-flavor of drinking vinegar when using a molded product without scratches.

[0182] Note that hereinafter, in this example, "off-flavor" includes not only a sense of disharmony in taste but also abnormal odors such as metallic odor.

[0183] [Evaluation criteria (beverage)] A: None of the 20 people felt an off-flavor. B: One or more and three or fewer of the 20 people felt an off-flavor. C: Four or more of the 20 people felt an off-flavor. D: Six or more of the 20 people felt an off-flavor.

[0184] (5) Sensory test - 2 (oil) Edible salad oil was poured into each molded product (with or without scratches). After a part of it was poured out from the mouth part, a lid was placed on the mouth part and stored at room temperature for one week. By this operation, the mouth part of the molded product was in a state where edible salad oil adhered. Next, 20 panelists were made to take a sip of the oil poured from the molded product into a clean glass cup, and the presence or absence and degree of off-flavor were evaluated according to the following criteria. The results are shown in the "Off-flavor" items in Tables 2 to 5. For example, "Off-flavor (oil, no scratch)" indicates the result regarding the off-flavor of edible salad oil when using a molded product without scratches.

[0185] [Evaluation Criteria (Oil)] A: None of the 20 people felt an abnormal odor. B: One or more and three or fewer of the 20 people felt an abnormal odor. C: Four or more of the 20 people felt an abnormal odor. D: Six or more of the 20 people felt an abnormal odor.

[0186]

Table 2

[0187]

Table 3

[0188]

Table 4

[0189]

Table 5

[0190] As shown in the table, when using the molded product that meets the requirements of the present invention, the abnormal odor was suppressed regardless of the presence or absence of scratches. On the other hand, when using the molded product that does not meet the requirements of the present invention, an abnormal odor occurred, and the degree was more deteriorated when there were scratches.

[0191] In particular, for the molded product using "inorganic powder 4", almost no abnormal odor was recognized with edible vinegar, but a clear abnormal odor was recognized with edible salad oil. This is presumably due to the lead contained in the molded product oxidizing the oil.

[0192] As the inorganic substance powder, together with the heavy calcium carbonate powder, other inorganic substance powders (in this example, titanium oxide) were also used, and results with the same tendency as above were obtained. Also, in the same manner as with "inorganic powder 7", when "inorganic powders 2" to "inorganic powder 6" were blended at a titanium oxide particle:calcium carbonate particle (mass ratio) = 10:90, results similar to those obtained when only "inorganic powders 2" to "inorganic powder 6" were used were obtained respectively. From this, it was found that using an inorganic substance powder that meets the requirements of the present invention does not significantly affect the results regardless of the type of the inorganic substance powder itself.

[0193] In this example, heavy calcium carbonate was employed as the inorganic substance powder, but the same tendency as described above was also observed with other inorganic substance powders (such as light calcium carbonate and talc).

[0194] Compared with a sheet composed of only a single layer, when a laminated sheet was used, the effect of suppressing off - flavors was exhibited more stably and effectively.

Claims

1. A sheet consisting of a single layer, or a sheet having a single layer portion and an ink receiving layer, The sheet is a sheet for forming a packaging container for food and beverages, The single layer or the single layer portion contains a thermoplastic resin and an inorganic substance powder, The content of the inorganic powder is 40.0% by mass or more and 80.0% by mass or less with respect to the sheet, The inorganic substance powder mainly contains calcium carbonate, The sheet, wherein the inorganic powder satisfies all of the following requirements: (Requirement 1) The lead content per gram of the inorganic substance powder is 20 μg or less. (Requirement 2) When the inorganic substance powder is taken as 100% by mass, the total amount of alkali metal and magnesium is 1.0% by mass or less. (Requirement 3) When the inorganic substance powder is taken as 100% by mass, the barium content is 0.030% by mass or less.

2. The sheet according to claim 1 , wherein the inorganic powder further satisfies the following requirements: (Requirement 4) The arsenic content per gram of the inorganic substance powder is 3 μg or less.

3. The resin composition according to claim 1 , wherein the content of the calcium carbonate is 80 mass % or more based on the inorganic substance powder.

4. 2. The sheet of claim 1, wherein the calcium carbonate comprises ground calcium carbonate.

5. The sheet according to claim 4, wherein the ground calcium carbonate contains ground calcium carbonate having an average particle size of 0.7 μm or more and 6.0 μm or less as measured by an air permeation method in accordance with JIS M-8511:2014.

6. The sheet according to claim 1 , wherein the thermoplastic resin comprises a polypropylene-based resin and / or a polyethylene-based resin.

7. The sheet according to claim 6 , wherein the polyethylene resin comprises high density polyethylene and / or linear low density polyethylene.

8. The sheet according to claim 6 , wherein the polypropylene-based resin comprises a polypropylene block polymer.

9. 9. The sheet of claim 1, wherein the sheet is for vacuum forming.

10. A packaging container for food and drink formed from the sheet of claim 9.

11. A laminated sheet of three or more layers, The laminated sheet is a sheet for forming a packaging container for food and beverages, The laminated sheet includes at least an inner layer, and a first outer layer and a second outer layer laminated on a surface of the inner layer, The inner layer includes an inorganic powder and a thermoplastic resin, the first outer layer and the second outer layer each comprise a thermoplastic resin; The content of the inorganic powder is 40.0% by mass or more and 80.0% by mass or less with respect to the laminate sheet, a ratio of the inorganic powder in the inner layer is greater than a ratio of the total amount of the inorganic powder in the first outer layer and the second outer layer; a ratio of a thickness of the first outer layer and a thickness of the second outer layer to a total thickness of the laminated sheet is 2.0% or more and 20.0% or less, The inorganic substance powder mainly contains calcium carbonate, A laminated sheet, wherein the inorganic powder satisfies all of the following requirements: (Requirement 1) The lead content per gram of the inorganic substance powder is 20 μg or less. (Requirement 2) When the inorganic substance powder is taken as 100% by mass, the total amount of alkali metal and magnesium is 1.0% by mass or less. (Requirement 3) When the inorganic substance powder is taken as 100% by mass, the barium content is 0.030% by mass or less.

12. The laminate sheet according to claim 11, wherein the inorganic powder further satisfies the following requirements: (Requirement 4) The arsenic content per gram of the inorganic substance powder is 3 μg or less.

13. The laminate sheet according to claim 11, wherein the content of the calcium carbonate is 80 mass % or more relative to the inorganic substance powder.

14. 12. The laminated sheet of claim 11, wherein the calcium carbonate comprises ground calcium carbonate.

15. The heavy calcium carbonate contains heavy calcium carbonate having an average particle size of 0.7 μm or more and 6.0 μm or less as measured by an air permeability method in accordance with JIS M-8511:2014. The laminate sheet according to claim 14.

16. The laminate sheet according to claim 11, wherein at least one of the inner layer, the first outer layer, and the second outer layer contains a polypropylene-based resin and / or a polyethylene-based resin as the thermoplastic resin.

17. The laminate sheet according to claim 16, wherein the polyethylene resin comprises high density polyethylene and / or linear low density polyethylene.

18. The laminate sheet according to claim 16, wherein the polypropylene-based resin comprises a polypropylene block polymer.

19. The laminate sheet according to claim 11 , wherein the ratio of the thickness of the first outer layer and the thickness of the second outer layer to the total thickness of the laminate sheet is 2.0% or more and 10.0% or less, respectively.

20. 20. The laminate sheet according to claim 11, wherein the laminate sheet is for vacuum forming.

21. A packaging container for food and drink formed from the laminate sheet of claim 20.

22. A packaging container for food and beverages consisting of a laminated sheet of three or more layers, The laminated sheet includes at least an inner layer, and a first outer layer and a second outer layer laminated on a surface of the inner layer, The inner layer includes an inorganic powder and a thermoplastic resin, the first outer layer and the second outer layer each comprise a thermoplastic resin; The content of the inorganic powder is 40.0% by mass or more and 80.0% by mass or less with respect to the laminate sheet, a ratio of the inorganic powder in the inner layer is greater than a ratio of the total amount of the inorganic powder in the first outer layer and the second outer layer; In at least a part of a cross section of the packaging container for food and beverages, the ratio of the thickness of the first outer layer and the thickness of the second outer layer to the total thickness of the laminated sheet is 2.0% or more and 20.0% or less, respectively; The inorganic substance powder mainly contains calcium carbonate, A packaging container for food and beverages, wherein the inorganic substance powder satisfies all of the following requirements: (Requirement 1) The lead content per gram of the inorganic substance powder is 20 μg or less. (Requirement 2) When the inorganic substance powder is taken as 100% by mass, the total amount of alkali metal and magnesium is 1.0% by mass or less. (Requirement 3) When the inorganic substance powder is taken as 100% by mass, the barium content is 0.030% by mass or less.

23. A laminated sheet for producing the packaging container for food and drink of claim 22 by vacuum forming.

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