Resin composition, molded article, sheet, and tray

Abstract

To provide a composition capable of reducing odor while containing eggshell powder.SOLUTION: The resin composition contains egg shell powder and a polyolefin-based polymer. The eggshell powder contains calcium carbonate as a main component, and the eggshell powder has a weight loss of 0.80 mass% or less from 25 °C to 250 °C when thermogravimetric analysis is performed at a temperature rising rate of 20 °C / min under a nitrogen atmosphere.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a resin composition, a molded article, a sheet, and a tray. [Background technology]

[0002] Resin compositions containing a mixture of eggshell powder and a polymer have been known for some time. For example, Patent Document 1 discloses a molded product containing a mixture of eggshell-derived calcium carbonate wet-pulverized to a specific particle size and a resin raw material. Patent Document 2 discloses a molded product containing a thermoplastic resin highly filled with eggshell powder. Patent Document 3 discloses a biodegradable resin composition containing a thermoplastic synthetic resin, eggshell micropowder, and a biodegradable organic substance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-256260 [Patent Document 2] WO2021 / 192427 publication [Patent Document 3] Patent Publication No. 2021-25021 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, from the viewpoint of effective utilization of waste, there has been a demand for using a resin composition containing eggshell powder for containers for food and the like.

[0005] However, the inventors have found through their investigations that when a conventional resin composition containing eggshell powder is molded into a container, an odor is emitted from the container.

[0006] The present invention has been made in view of the above problems, and aims to provide a resin composition containing eggshell powder and producing a molded product with little odor. [Means for solving the problem]

[0007] [1] Contains eggshell powder and a polyolefin polymer, The eggshell powder contains calcium carbonate as a main component, The eggshell powder is a resin composition in which, when subjected to thermogravimetric analysis in a nitrogen atmosphere at a heating rate of 20°C / min, the weight loss from 25°C to 250°C is 0.80% by mass or less. [2] The resin composition according to claim 1, wherein the eggshell powder is contained in an amount of 10 to 200 parts by mass per 100 parts by mass of the polyolefin polymer. [3] A molded article of the resin composition according to [1] or [2]. [4] A laminate comprising an intermediate layer of the resin composition according to [1] or [2], a first coating layer covering one main surface of the intermediate layer, and a second coating layer covering the other main surface of the intermediate layer, wherein the first coating layer and the second coating layer are layers of a resin composition that does not contain eggshell powder. [5] The laminate according to [4], wherein the first coating layer and the second coating layer have a thickness of 5 to 50 μm. [6] A molded product of the laminate of [4] or [5]. [7] The molded article according to [3] or [6], which is a sheet or tray. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a resin composition that contains eggshell powder and yet produces molded articles with little odor. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a cross-sectional view of a laminate according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of a tray of the laminate according to the embodiment. [Figure 3] TG charts of eggshell powder A, eggshell powder B, eggshell powder B*, and precipitated calcium carbonate powder C. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, several embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments.

[0011] (composition) The composition according to the present embodiment contains eggshell powder and a polyolefin polymer.

[0012] (eggshell powder) Eggshell flour is made from crushed animal eggs, such as chickens and other birds.

[0013] Eggshell powder is mainly composed of calcium carbonate (CaCO3). By "main component," we mean 50% by mass or more. The proportion of calcium carbonate may be 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or 98% by mass or more.

[0014] When the eggshell powder is subjected to thermogravimetric analysis in a nitrogen atmosphere at a heating rate of 20°C / min, the weight loss from 25°C to 250°C is 0.80% by mass or less. The weight loss may be 0.70% by mass or less, 0.60% by mass or less, or 0.50% by mass or less.

[0015] Such eggshell powder can be obtained, for example, by heat-treating eggshell powder in an oxidizing atmosphere such as air within a temperature range that does not cause decarbonation, thereby removing organic matter such as eggshell membrane (protein). For example, calcium carbonate undergoes decarbonation and decomposition at temperatures above 600°C under normal pressure, and from the viewpoint of sufficiently oxidatively decomposing and removing organic matter such as eggshell membrane (protein), the heat treatment temperature is preferably 400 to 550°C. The heat treatment time is preferably 1 hour or longer, but may be 10 hours or longer, 24 hours or longer, or 48 hours or longer. It is preferable to circulate air sufficiently during the heat treatment to ensure ample contact with oxygen.

[0016] Conventional methods such as centrifugation, alkali treatment, and enzyme treatment cannot sufficiently remove organic matter from eggshell powder, making it difficult to achieve a low concentration of, for example, 0.80% by mass or less of weight loss in the temperature range measured by thermogravimetric analysis.

[0017] Furthermore, in a heat treatment at a high temperature, such as 900 to 1000°C, in addition to removing organic matter, the calcium carbonate in the eggshell powder is thermally decomposed to calcium oxide (CaO), or further absorbs moisture to become calcium hydroxide (Ca(OH)2), and the eggshell powder of this embodiment cannot be obtained.

[0018] Furthermore, calcium carbonate obtained by dissolving the calcium oxide thus obtained in water to obtain lime water and then reacting it with carbon dioxide to reprecipitate is called light calcium carbonate, which does not contain organic matter. However, since the calcium derived from eggshells is once dissolved in water and becomes a cation, and the porous structure of eggshell powder is lost, the reprecipitated product cannot be called eggshell powder, and is not included in the eggshell powder of this embodiment.

[0019] Although there are no particular limitations on the particle size distribution of eggshell powder, it is preferable that the D50 of the volume-based frequency distribution based on laser diffraction is 0.1 to 30 μm. D50 may be 0.5 μm or more, 1 μm or more, 2 μm or more, 5 μm or more, or 10 μm or more. D50 may also be 25 μm or less, or 20 μm or less.

[0020] It is preferable that the eggshell powder does not have particles of 100 μm or larger in size when measured by laser diffraction.

[0021] (Polyolefin polymer) Examples of polyolefin polymers include olefin polymers such as low-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene, and cyclic polyolefins, copolymers thereof, and modified products thereof. The polyolefin polymer may also be a copolymer of ethylene and / or propylene with an α-olefin having 4 or more carbon atoms, such as an ethylene-α-olefin copolymer or a propylene-α-olefin copolymer.

[0022] The polyolefin polymer may be a mixture of any two or more of various polymers.

[0023] (Polypropylene polymer) The polyolefin polymer is particularly preferably a polypropylene polymer, since it is lightweight and has excellent heat resistance, chemical resistance, and moldability.

[0024] The polypropylene polymer may be a polymer containing more than 50 mol% to 100 mol% of propylene units in 100 mol% of all structural units constituting the polymer, and the proportion of propylene units may be 60% or more, 70% or more, 80% or more, 90% or more, or 95% or more.

[0025] The polypropylene polymer is not particularly limited as long as it does not impair the effects of the present invention, and may contain, for example, a homopolypropylene, which is a homopolymer of propylene, a random polypropylene obtained by copolymerizing polypropylene and ethylene, a block polypropylene obtained by blending an elastomer component of an ethylene-propylene copolymer during polypropylene polymerization, or the like, either alone or in combination.

[0026] Examples of other monomers copolymerizable with propylene include ethylene and α-olefins. The α-olefins have 4 or more carbon atoms, preferably 4 to 12 carbon atoms. Specific examples of α-olefins having 4 to 12 carbon atoms include linear monoolefins such as 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, and 1-decene; branched monoolefins such as 3-methyl-1-butene, 3-methyl-1-pentene, and 4-methyl-1-pentene; and vinylcyclohexane. The copolymer of propylene and another monomer copolymerizable therewith may be a random copolymer or a block copolymer.

[0027] Specific examples of the copolymer include binary or ternary copolymers of propylene with ethylene and one or more monomers selected from the group consisting of α-olefins having 4 to 12 carbon atoms, such as propylene-ethylene copolymer, propylene-1-butene copolymer, and propylene-ethylene-1-butene copolymer.

[0028] The stereoregularity of the propylene homopolymer and the propylene copolymer may be isotactic, syndiotactic, or atactic, but from the viewpoint of achieving an excellent balance between rigidity and transparency after being formed into a film, polypropylene with a high isotacticity is preferred.

[0029] The polypropylene-based polymer may account for 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, 60% by mass or more, 70% by mass or more, or 80% by mass or more of the polyolefin-based polymer.

[0030] (Polyethylene polymer) The polyolefin polymer may contain a polyethylene polymer instead of or in addition to the polypropylene polymer.

[0031] A polyethylene polymer refers to a resin that contains more than 50 mol% but not more than 100 mol% of ethylene units, based on 100 mol% of all structural units constituting the resin. The proportion of ethylene units may be 60% or more, 70% or more, 80% or more, 90% or more, or 95% or more.

[0032] The polyethylene polymer may be an ethylene homopolymer or a copolymer of ethylene and an α-olefin, examples of which are those described for the polypropylene polymer.

[0033] Examples of polyethylene polymers include low-density polyethylene (LDPE: a polyethylene having a density measured by a high-pressure method (hereinafter simply referred to as density) of 900 to 945 kg / m 3 High density polyethylene (HDPE: density 945 kg / m 3 and linear low-density polyethylene (LLDPE: produced by a low-pressure process using single-site or multi-site catalysts and with a density of 900-945 kg / m 3 Polyethylene is a

[0034] The polyethylene polymer may be a mixture of linear low density polyethylene (LLDPE) and high density polyethylene (HDPE).

[0035] The polyethylene polymer may account for 10% by mass or more of the polyolefin polymer, 20% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, 60% by mass or more, 70% by mass or more, or 80% by mass or more.

[0036] Furthermore, the polyethylene-based polymer may account for 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more of the components other than the polypropylene-based polymer in the polyolefin-based polymer.

[0037] (additives) The composition may further contain various additives, such as antioxidants, ultraviolet absorbers, antistatic agents, lubricants, antifogging agents, antiblocking agents, and deodorizers.

[0038] Examples of antioxidants include phenolic antioxidants, phosphorus-based antioxidants, etc. It is also preferred to use phosphorus-phenolic antioxidants, which are composite antioxidants having units that combine the antioxidant mechanisms of both phenolic and phosphorus in one molecule.

[0039] Examples of phenolic antioxidants include 2,6-di-tert-butyl-4-methylphenol, n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenylacrylate, and tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane (Irganox 1010).

[0040] Examples of phosphorus-based antioxidants include tris(2,4-di-tert-butylphenyl)phosphite (Irgaphos 168), tris[2-[[2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphen-6-yl]oxy]ethyl]amine, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis[2,4-bis(1,1-dimethylethyl)-6-methylphenyl]ethyl ester phosphorous acid, and tetrakis(2,4-di-tert-butylphenyl)[1,1-biphenyl]-4,4'-diylbisphosphonite.

[0041] Phosphorus-phenolic antioxidants can be compounds containing at least one phosphorus atom and at least one phenol structure in the molecule. Examples of phosphorus-phenolic antioxidants include (6-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butyldibenz[d,f][1.3.2]dioxaphosphepine) (Sumilizer GP).

[0042] Examples of the ultraviolet absorber include known ultraviolet absorbers such as 2-hydroxybenzophenone derivatives and hydroxyphenylbenzotriazole derivatives, and benzoate-based ultraviolet blocking agents.

[0043] The antistatic agent may be any of oligomer type, monomer type, and permanently antistatic polymer type typified by polyether / polyolefin block polymer, etc. An example of polyether / polyolefin block polymer is Pelektron PVL manufactured by Sanyo Chemical Industries.

[0044] Examples of the lubricant include higher fatty acid amides such as erucic acid amide and oleic acid amide, higher fatty acids such as stearic acid, and salts thereof.

[0045] As the anti-blocking agent, spherical or nearly spherical fine particles can be used, whether inorganic or organic.

[0046] As a deodorizer, silica alumina gel powder (ZnO SiO ) containing silica zinc particles was used. x ·Al2O3·nH2O).

[0047] The resin composition may contain calcium carbonate powder other than the above-mentioned eggshell powder. Examples of such calcium carbonate powder include heavy calcium carbonate powder obtained by crushing limestone and light calcium carbonate powder obtained by blowing carbon dioxide gas into milk of lime to precipitate the calcium carbonate.

[0048] The resin composition may contain a resin other than the above polymer.

[0049] (Composition ratio of resin composition) The mass proportion of the eggshell powder in the resin composition is not particularly limited, but the eggshell powder may be contained in an amount of 10 to 200 parts by mass per 100 parts by mass of the polyolefin polymer. The lower limit may be 15 parts by mass, 20 parts by mass, 30 parts by mass, or 40 parts by mass, and the upper limit may be 175 parts by mass, 150 parts by mass, or 125 parts by mass.

[0050] In the resin composition, the total mass proportion of the polyolefin polymer and eggshell powder may be 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or 100% by mass or more.

[0051] There are no particular limitations on the amount of additives added to the resin composition, and each additive may be added in an amount of 1% by mass or less based on the composition.

[0052] (Method of producing resin composition) The composition can be obtained by melt-kneading the eggshell powder, the polyolefin polymer, and additives that are added as needed.

[0053] The temperature during kneading is preferably 250° C. or lower, more preferably 240° C. or lower, and even more preferably 230° C. or lower. A lower temperature such as 190° C. is preferred during kneading, but the kneading can be carried out at a temperature set depending on the fluidity of the resin composition and the load on the extruder.

[0054] The composition can be pelletized to form a molding material.

[0055] (Laminate) 1 shows an example of a laminate according to this embodiment.

[0056] As shown in Figure 1, the laminate 100 of this embodiment comprises an intermediate layer 20 of the above-mentioned resin composition, a first coating layer 10 covering one main surface of the intermediate layer 20, and a second coating layer 30 covering the other main surface of the intermediate layer 20.

[0057] The thickness of the intermediate layer 20 can be set to, for example, 80 to 950 μm.

[0058] The first coating layer 10 and the second coating layer 30 are layers of a resin composition that does not contain eggshell powder. There are no particular limitations on the composition of the resin composition, and it can be the same as the compositions exemplified above, except that it does not contain eggshell powder. Other than the presence or absence of eggshell powder, the composition of the first coating layer and the second coating layer may be the same as or different from that of the intermediate layer 20. Furthermore, the composition of the first coating layer 10 and the second coating layer 30 may be the same as or different from that of the intermediate layer 20.

[0059] For example, the first coating layer 10 and the second coating layer 30 preferably contain a polyolefin-based polymer. Examples of the polyolefin-based polymer are as described above, and may include, for example, a polypropylene-based polymer such as block polypropylene, and / or a polyethylene-based polymer such as HDPE or LLDPE.

[0060] The thickness of the first coating layer 10 and the second coating layer 30 may be 5 μm or more, 10 μm or more, 100 μm or less, or 50 μm or less. The thickness of the first coating layer 10 and the second coating layer 30 may be the same as or different from each other.

[0061] Such a laminate can be obtained by a known method for producing laminated sheets, such as coextrusion from a T-die or thermal lamination of three sheets.

[0062] The temperature of the resin during production of the laminate is preferably 250° C. or less, more preferably 240° C. or less, and even more preferably 230° C. or less. A lower temperature such as 190° C. is preferred, but the temperature can be set depending on the fluidity of the resin composition and the load on the extruder.

[0063] Such a laminate is particularly suitable for food use, since the resin layer containing eggshell powder is not exposed on the surface.

[0064] (Molded body) The molded article is a molded article of the resin composition or laminate described above. There are no particular limitations on the molding method. For example, the resin composition may be extruded through a die such as a T-die to obtain a single-layer or laminated sheet, tube, or the like.

[0065] The thickness of the sheet can be 0.1 to 1.0 mm. The sheet or laminate may also be thermoformed by vacuum forming, vacuum pressure forming or the like to obtain a tray or the like.

[0066] The resin composition may be injection molded to obtain a three-dimensional molded product, or may be blow molded to obtain a hollow bottle-shaped product. The shape of the molded product is not particularly limited.

[0067] The molded article is particularly suitable for food applications, such as food packaging films and food trays.

[0068] Such molded articles can be used under low temperatures such as during freezing treatment and frozen transportation, as well as under high temperatures such as during microwave cooking.

[0069] After obtaining pellets of the composition, the pellets may be melt-kneaded again to obtain a molded product, but it is also possible to melt-knead the eggshell powder, the polyolefin polymer, and additives added as needed, and then mold the mixture as is to obtain a molded product.

[0070] (tray) The tray according to this embodiment is formed from the laminate described above or a single layer sheet 50 of the composition. Figure 2 is a cross-sectional view showing one embodiment of a tray 200 according to the laminate. The tray 200 shown in Figure 2 has a recess.

[0071] The tray can be manufactured, for example, by thermoforming a sheet. Examples of thermoforming methods include vacuum forming, pressure forming, vacuum pressure forming, and hot plate pressure forming. Specific examples include free drawing, plug and ring forming, ridge forming, matched mold forming, straight forming, drape forming, reverse draw forming, air slip forming, plug assist forming, plug assist reverse draw forming, and contact heating pressure forming.

[0072] (Action and effect) The resin composition according to the present embodiment uses a specific eggshell powder, which makes it possible to suppress the generation of odor. The reason for this is unclear, but the following mechanism is thought to be responsible.

[0073] The eggshell powder of this embodiment shows extremely little mass loss in thermogravimetric analysis at 25 to 250°C. This characteristic means that the eggshell powder used in this embodiment contains very little organic matter, such as eggshell membrane (protein). This mass loss level is thought to be comparable to that of precipitated calcium carbonate powder, and some or most of this mass loss is thought to be due to, for example, adsorbed water. Therefore, odor generation from molded articles is suppressed. Molded articles using such resin compositions are particularly suitable for food and the like.

[0074] Unlike the present embodiment, conventional calcined eggshell powder is calcined at a considerably high temperature, such as 900°C, to produce calcium oxide, or calcium hydroxide by further reacting with water, which differs from the calcium carbonate-based composition of the present embodiment. These conventional eggshell powders dissolve in water and exhibit strong alkalinity, so their addition to resin compositions is often not preferred.

[0075] Furthermore, according to this embodiment, cold impact resistance is improved, which is thought to be because deterioration of the polyolefin polymer due to eggshell membrane (protein) is suppressed. [Example]

[0076] (raw materials) PP-1: Block polypropylene: SunAllomer VB170A (b-PP) PP-2: Random polypropylene: Sumitomo Chemical Sumitomo Noblen S131 (r-PP) LLDPE: Linear low-density polyethylene (Japan Evolue SP3010) MB1: Low-density polyethylene masterbatch containing 80% by mass of eggshell powder A MB2: Low-density polyethylene masterbatch containing 70% by mass of eggshell powder B MB3: Light calcium carbonate 30 mass-containing block polypropylene masterbatch

[0077] (Preparation of eggshell powder A and masterbatch MB1) Raw eggshells (mainly CaCO3) were crushed into powder and placed in a heat-resistant container. The heat-resistant container was placed in a muffle furnace equipped with an air inlet tube and fired at 500°C for 72 hours while blowing air at a flow rate of 30 mL / min to obtain eggshell powder A.

[0078] Eggshell powder A and linear low-density polyethylene resin LLDPE were fed into an extruder in a blending ratio of 80:20, melted and mixed in a twin-screw extruder adjusted to a resin temperature of 190°C, and thread-like strands were extruded from a die, cooled with water, and then cut in a pelletizer to produce pellets of masterbatch MB1.

[0079] (Preparation of eggshell powder B and masterbatch MB2) Raw eggshells were washed with water, crushed, and then centrifuged to remove approximately 95 wt% of the eggshell membrane. This resulted in the use of Masterbatch MB2 (MB with eggshell powder: EG70L-LS, manufactured by Nexus Corporation), a low-density polyethylene resin composition containing 70 wt% of unbaked eggshell powder B.

[0080] (Preparation of eggshell powder B*) Unbaked eggshell powder B* was prepared in the same manner as eggshell powder B, except that the eggshell membrane was not removed using a centrifuge.

[0081] (Heavy calcium carbonate masterbatch MB3) Masterbatch MB3, a block polypropylene resin composition containing 70 wt% heavy calcium carbonate, was manufactured by J-Wing Co., Ltd. and used was JWP170B.

[0082] (Light calcium carbonate powder C) Raw eggshells were washed with water, placed in a ceramic container, and placed in a muffle furnace. They were fired at 900°C for 4 hours, then naturally cooled to below 200°C before being removed, yielding white CaO or Ca(OH)2. They were then crushed in a mortar and powdered. 1g of the powder was sampled and added to 1L of water, stirred at room temperature for 2 hours, and the insoluble matter was filtered off to obtain limewater. The pH measured with a pH meter was 12.2. A stir bar was then placed in the limewater and stirred on a magnetic stirrer. CO2 gas was blown in through a straw while measuring the pH. When the pH reached 8.54, the precipitate was filtered and sampled, yielding precipitate C, light calcium carbonate (CaCO3) powder C.

[0083] (Thermogravimetric analysis of eggshell powders A, B, B* and precipitated calcium carbonate powder C) Thermogravimetric analysis was performed on eggshell powders A, B, B*, and precipitated calcium carbonate powder C in a nitrogen atmosphere at a heating rate of 20°C / min. Specifically, approximately 10 to 15 mg of eggshell powder was placed in a quartz cell and heated in a thermogravimetric analyzer at a N2 flow rate of 200 ml / min and a heating rate of 20°C / min. The weight loss was monitored as the temperature rose from room temperature to 900°C. A graph of weight change versus temperature is shown in Figure 3.

[0084] The weight loss of eggshell powder A from 25°C to 250°C was 0.41% by mass. The weight loss of eggshell powder B from 25°C to 250°C was 0.98% by mass. The weight loss of eggshell powder B* from 25°C to 250°C was 1.71% by mass. The weight loss of precipitated calcium carbonate powder C was 0.33% by mass. The TG chart of precipitated calcium carbonate powder C was essentially the same as that of eggshell powder A. As a reference example, the TG chart of calcium hydroxide (Ca(OH)2) is also shown. Calcium hydroxide begins to lose weight above 400°C, and the weight loss at 500°C was 19.1% by mass, showing different behavior from other eggshell powders such as eggshell powder A. Weight loss results are shown in Table 1.

[0085] [Table 1]

[0086] Example 1 A laminate sheet with a structure of first coating layer / intermediate layer / second coating layer was produced by coextrusion at 230°C.

[0087] The composition (parts by mass) of the intermediate layer was the intermediate layer charge composition in Table 1, and the compositions (parts by mass) of the first coating layer and the second coating layer were each the outer layer mass compositions in Table 1. The thickness of the intermediate layer was 460 μm, and the thickness of the first coating layer and the second coating layer was 20 μm.

[0088] The obtained laminate sheet was heated with upper and lower heaters adjusted to 500°C, and after the sheet was drawn down and then stretched back (approximately 9 seconds), it was vacuum-formed to obtain a tray with a width of 118 mm, a length of 139 mm, a depth of 30 mm, and a flange with a periphery width of 5 mm.

[0089] (Examples 2 and 3, Comparative Examples 1 and 2) A laminate sheet and a tray were obtained in the same manner as in Example 1, except that the composition of the intermediate layer was as shown in Table 1.

[0090] (evaluation) (Odor of laminated sheet immediately after molding, odor of tray immediately after molding) The laminate sheet and the tray were smelled by a person and rated as follows: ◎: No odor detected at all, ◯: Almost no odor detected, △: Odor detected, ×: Very strong odor detected.

[0091] (Odor from tray after microwave cooking) The tray was filled with water up to about 10 mm from the bottom, and cooked in a 600W microwave oven, first heating it to 100°C while measuring the temperature with a fiber optic thermometer, and then maintaining the boiling state for 1 minute.The odor of the tray was then evaluated by a person by smelling it. ◎: No odor detected at all, ◯: Almost no odor detected, △: Odor detected, ×: Very strong odor detected.

[0092] (Tray deformation after microwave cooking) The tray was filled with salad oil up to about 10 mm from the bottom, and cooked in a 600W microwave oven up to 130°C while measuring the temperature with a fiber optic thermometer. The degree of deformation was then evaluated visually. ◯: No warping or deformation was visible to the naked eye; △: Slight warping, deformation, and surface melting was visible to the naked eye; ×: Significant deformation was observed.

[0093] (Impact strength measurement of laminated sheet in DuPont impact test) A test piece of the laminate measuring 50 mm long x 50 mm wide was prepared, and the 50% fracture energy E50 (J) of this test piece was measured using a DuPont impact tester in accordance with JIS K 7124. The test was carried out at both 23°C and -20°C.

[0094] The results are shown in Table 2.

[0095] [Table 2]

[0096] In the Examples, odor was suppressed compared to the Comparative Examples during sheet formation, tray formation, and cooking. [Explanation of symbols]

[0097] 10...first coating layer, 20...intermediate layer, 30...second coating layer, 100...laminated body (molded body), 200...tray (molded body).

Claims

1. The composition comprises eggshell powder and a polyolefin polymer, The eggshell powder contains calcium carbonate as a main component, The eggshell powder has a weight loss of 0.80% by mass or less from 25°C to 250°C when subjected to thermogravimetric analysis at a heating rate of 20°C / min in a nitrogen atmosphere.

2. The resin composition according to claim 1, wherein the eggshell powder is contained in an amount of 10 to 200 parts by mass per 100 parts by mass of the polyolefin polymer.

3. A molded article made from the resin composition according to claim 1.

4. 10. A laminate comprising an intermediate layer of the resin composition according to claim 1, a first coating layer covering one main surface of the intermediate layer, and a second coating layer covering the other main surface of the intermediate layer, wherein the first coating layer and the second coating layer are layers of a resin composition that does not contain eggshell powder.

5. The laminate according to claim 4, wherein the first coating layer and the second coating layer have a thickness of 5 to 50 μm.

6. A molded article made from the laminate according to claim 4.

7. 7. The molded article according to claim 3 or 6, which is a sheet or a tray.

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