Multilayer molded container, bottle, tube, and recycled resin composition

Abstract

The present disclosure relates to a multilayer molded container comprising at least: an inner layer containing a pigment 1 and a recycled resin obtained using PET bottle caps; and an outer layer containing a white pigment 2 and a resin 2.

Description

Multilayer molded container, bottle, tube, and recycled resin composition

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a multilayer molded container, a bottle, a tube, a recycled resin composition, and a method for producing a multilayer molded container.

[0002] Due to their properties of transparency, design, light weight, and safety, polyester bottles are used in many fields, including food, healthcare, cosmetics, and medicine, and their usage is expanding.In addition, with the recent promotion of a recycling-oriented society, the polyester used to make polyester bottles is being recycled into bottles, daily necessities, clothing, and other products, achieving a high recycling rate.

[0003] For example, Patent Document 1 describes a biaxially oriented polyester film roll obtained by winding up a biaxially oriented polyester film made of a polyester resin composition containing particles and a polyester resin made from recycled PET bottles.

[0004] International Publication No. 2022 / 049998

[0005] On the other hand, polyolefin resins are often used for the caps of polyester bottles because they are highly resistant to the contents and easy to mold. Furthermore, to enhance the design of the caps, polyolefin resins are colored with a wide variety of pigments. Therefore, the recycling applications of caps are currently limited.

[0006] Therefore, an object of an embodiment of the present invention is to provide a new use for recycled resin obtained from PET bottle caps.

[0007] The present invention includes the following embodiments, but is not limited to the following embodiments.

[0008] One embodiment relates to a multilayer molded container having at least an inner layer containing a recycled resin obtained using PET bottle caps and pigment 1, and an outer layer containing white pigment 2 and resin 2. Another embodiment relates to a recycled resin composition used to manufacture the multilayer molded container, containing a recycled resin obtained using PET bottle caps and pigment 1. Another embodiment relates to a method for manufacturing a multilayer molded container, including molding an inner layer material containing a recycled resin obtained using PET bottle caps and pigment 1, and an outer layer material containing white pigment 2 and resin 2, by a blow molding method or an extrusion molding method.

[0009] According to one embodiment of the present invention, a multilayer molded container is provided as a new application for recycled resin obtained from PET bottle caps. According to another embodiment of the present invention, a recycled resin composition suitable for multilayer molded containers is provided. According to yet another embodiment of the present invention, a method for producing a multilayer molded container is provided as a new application for recycled resin obtained from PET bottle caps.

[0010] The following describes embodiments of the present invention, but the embodiments of the present invention are not limited to the following.

[0011] <<Multilayer Molded Container>> In an embodiment of the present invention, the multilayer molded container has at least an inner layer containing a recycled resin obtained using a PET bottle cap and pigment 1, and an outer layer containing a white pigment 2 and resin 2. The inner layer may further contain resin 1. "Pigment 1" refers to the pigment contained in the inner layer, "resin 1" refers to a resin other than the recycled resin contained in the inner layer, "white pigment 2" refers to the white pigment contained in the outer layer, and "resin 2" refers to the resin contained in the outer layer. The multilayer molded container may further have any layers, such as an adhesive layer or another resin layer.

[0012] PET bottle caps have a unique color for each product, from the perspectives of design, distinctiveness, and the like, and are formed from resin compositions containing colorants corresponding to each product. When recycled resin compositions are obtained by collecting various used PET bottle caps, the recycled resin compositions contain a variety of colorants and recycled resins. Currently, recycled resin compositions have limited uses due to the colors imparted by the colorants. To expand recycling applications, it has been considered to separate collected PET bottle caps by color or to separate and remove colorants from the recycled resin composition, but this is difficult to put into practical use due to complexity, cost, and other factors. In contrast, embodiments of the present invention have found new uses for PET bottle caps by adopting a multilayer structure. According to embodiments of the present invention, PET bottle cap waste can be reduced, environmental impact can be reduced, and a resource-circulating society can be realized. Furthermore, from the perspective of manufacturing molded containers, the present invention has the effects of reducing raw material costs and producing containers at low cost, as well as excellent design. However, embodiments of the present invention are not limited to PET bottle caps that are not separated by color, and various PET bottle caps, such as PET bottle caps that are separated by color, can be used.

[0013] <Inner Layer> The inner layer contains a resin obtained using a PET bottle cap and a pigment 1. The inner layer may further contain optional components such as resin 1 and additives. The inner layer can be formed, for example, using a recycled resin composition obtained by recycling a PET bottle cap. Since a PET bottle cap usually contains a resin, a pigment, an additive, etc., the recycled resin composition contains a recycled resin, a pigment, an additive, etc. obtained from the cap.

[0014] [Recycled Resin] Recycled resin is a resin obtained using PET bottle caps. PET bottle caps are generally made of polyethylene (PE) and / or polypropylene (PP). Examples of polyethylene include high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), etc., and high-density polyethylene is preferred. Therefore, the recycled resin may contain at least one selected from the group consisting of polyethylene and polypropylene, and preferably contains at least one selected from the group consisting of high-density polyethylene and polypropylene. When the recycled resin contains at least one selected from the group consisting of high-density polyethylene and polypropylene, a highly rigid container tends to be obtained.

[0015] The content ratio of polyethylene to polypropylene in the recycled resin is not particularly limited. When PET bottle caps are collected without any separation to obtain a recycled resin composition, the recycled resin in the composition typically contains polyethylene and polypropylene in a ratio of (mass (g) of polyethylene) > (mass (g) of polypropylene). The mass (g) of polyethylene:mass (g) of polypropylene is, for example, 60-95:5-40, 70-95:5-30, 70-95:5-30 (excluding 80-90:10-20), 65-93:7-35, or 70-90:10-30. However, the content ratio of polyethylene to polypropylene varies depending on the collection conditions, such as the season and region, in which used PET bottles are collected, and is therefore not limited to the above range. Caps for PET bottles for cold drinks are often made of polyethylene, while caps for PET bottles for hot drinks are often made of polypropylene. If necessary, the PET bottle caps may be separated to obtain a recycled resin composition from specific PET bottle caps, and the mass (g) of polyethylene:mass (g) of polypropylene may be, for example, 95 to 100:0 to 5, or 0 to 60:40 to 100.

[0016] From the viewpoint of moldability, the ratio of the mass (g) of polyethylene to the mass (g) of polypropylene in the recycled resin is preferably 80 to 100:0 to 20. From the viewpoint of strength, it is more preferably 80 to 90:10 to 20. In an embodiment of the present invention, the ratio of the mass (g) of polyethylene to the mass (g) of polypropylene can be determined from the peak intensities of polyethylene and polypropylene by infrared spectroscopic analysis according to JIS K0117:2017, for example.

[0017] The melt mass flow rate (MFR) of the recycled resin composition is preferably 0.1 to 10 g / 10 min, 1 to 10 g / min, or 2 to 10 g / 10 min. In an embodiment of the present invention, the MFR can be determined in accordance with JIS K 7210-1:2014 under conditions of 190°C and a load of 2.16 kg.

[0018] From the viewpoint of moldability, the density of the recycled resin composition is 930 to 970 kg / m ３ , or 950 to 970 kg / m ３ In an embodiment of the present invention, the density can be determined by a water displacement method in accordance with JIS K 7112:2023.

[0019] The content of the recycled resin composition in the inner layer is, for example, 15 to 80% by mass, 20 to 80% by mass, 30 to 75% by mass, or 40 to 70% by mass, based on the inner layer (100% by mass of the inner layer). When the content is 20% by mass or more, the amount of petroleum-derived resin can be reduced by using recycled materials. When the content is 80% by mass or less, good moldability can be maintained in blow molding or extrusion molding.

[0020] The content of the recycled resin in the inner layer is, for example, 13 to 80% by mass, 18 to 80% by mass, 27 to 75% by mass, or 36 to 70% by mass, based on the inner layer (100% by mass of the inner layer). When the content is 13% by mass or more, the amount of petroleum-derived resin can be reduced by using recycled materials. When the content is 80% by mass or less, good moldability can be maintained in blow molding or extrusion molding.

[0021] [Pigment 1] The inner layer contains pigment 1. Pigment 1 includes a pigment derived from a PET bottle cap contained in the recycled resin composition. The pigment derived from a PET bottle cap means a pigment that was contained in the PET bottle cap. Pigment 1 may further contain a pigment other than the pigment derived from the PET bottle cap. The pigment derived from the PET bottle cap may be referred to as "pigment 1a," and a pigment other than pigment 1a may be referred to as "pigment 1b."

[0022] Pigment 1a typically contains two or more pigments, for example, five or more, or ten or more pigments. Pigment 1a and pigment 1b may contain the same pigment or may not contain the same pigment. For example, pigment 1a may contain titanium oxide derived from a white cap, and pigment 1b may also contain titanium oxide. Examples of pigment 1 include organic pigments and inorganic pigments.

[0023] Examples of organic pigments include azo pigments, quinacridone pigments, perylene pigments, isoindolinone pigments, diketopyrrolopyrrole pigments, phthalocyanine pigments, etc. More specific examples of organic pigments include monoazo yellow, disazo yellow, monoazo orange, quinacridone red, diketopyrrolopyrrole red, phthalocyanine green, phthalocyanine blue, quinacridone violet, etc. Pigment 1 may contain at least one selected from the group consisting of monoazo yellow, disazo yellow, monoazo orange, quinacridone red, diketopyrrolopyrrole red, phthalocyanine green, phthalocyanine blue, and quinacridone violet; or may contain at least one selected from the group consisting of monoazo yellow, disazo yellow, monoazo orange, quinacridone red, diketopyrrolopyrrole red, phthalocyanine green, phthalocyanine blue, and quinacridone violet (excluding Pigment Yellow 181 and Pigment Red 254). By including these pigments in Pigment 1, the nucleating effect of the pigments can maintain moldability during molding of multilayer molded containers such as blow bottles, even when recycled materials are used. Pigment 1a, Pigment 1b, or both may contain these pigments.

[0024] Specific examples of azo pigments include C.I. Pigment Yellow 93, 95, 150, 151, 168, 169, 180, 181, C.I. Pigment Red 144, 208, 214, etc.; specific examples of quinacridone pigments include C.I. Pigment Red 122, 207, C.I. Pigment Bio Red 19, etc.; specific examples of perylene pigments include C.I. Pigment Red 149, 178, etc.; specific examples of isoindolinone pigments include C.I. Pigment Yellow 109, 110, 139, C.I. Pigment Orange 61, etc.; specific examples of diketopyrrolopyrrole pigments include C.I. Pigment Red 254, 264, C.I. Pigment Orange 71, etc.; specific examples of phthalocyanine pigments include C.I. Examples of the pigments include C.I. Pigment Green 7, 36, and C.I. Pigment Blue 15. Pigment 1 may contain, for example, at least one pigment selected from the group consisting of Pigment Yellow 181 and Pigment Red 254. Pigment 1 may contain at least one pigment selected from the group consisting of monoazo yellow, disazo yellow, monoazo orange, quinacridone red, diketopyrrolopyrrole red, phthalocyanine green, phthalocyanine blue, and quinacridone violet (excluding Pigment Yellow 181 and Pigment Red 254), and may further contain at least one pigment selected from the group consisting of Pigment Yellow 181 and Pigment Red 254. Pigment 1a, Pigment 1b, or both may contain these pigments.

[0025] A specific example of Pigment Yellow 93 is Cromophtal Yellow 3GNP (manufactured by BASF), a specific example of Pigment Yellow 95 is Cromophtal Yellow GRP (manufactured by BASF), a specific example of Pigment Yellow 150 is Binamon Yellow 115002 (manufactured by Heubach), a specific example of Pigment Yellow 151 is PV Fast Yellow H4G (manufactured by Clariant), a specific example of Pigment Yellow 168 is Lionol Yellow K5G (manufactured by Toyocolor), a specific example of Pigment Yellow 169 is Lionol Yellow K2R (manufactured by Toyocolor), A specific example of Pigment Yellow 180 is PV Fast Yellow HG (manufactured by Clariant), a specific example of Pigment Yellow 181 is PV Fast Yellow H3R (manufactured by Clariant), a specific example of Pigment Red 144 is Chromophtal Red BRN (manufactured by BASF), a specific example of Pigment Red 208 is Grafthol Red HF2B (manufactured by BASF), a specific example of Pigment Red 214 is Chromophtal Red BN (manufactured by BASF), and specific examples of Pigment Red 122 are Fastgen Super Magenta RE03 (manufactured by DIC) and Binamon Red 3 12201 (manufactured by Heubach), a specific example of Pigment Red 207 is Fastogen Super Scarlet GK (manufactured by DIC), a specific example of Pigment Bio Red 19 is Chromophthal Red 2020 (manufactured by BASF), a specific example of Pigment Red 149 is Paliogen Red K3580 (manufactured by BASF), a specific example of Pigment Red 178 is Paliogen Red K3911HD (manufactured by BASF), a specific example of Pigment Yellow 110 is Helmcol Yellow 3RLT (manufactured by Hermeta), a specific example of Pigment Yellow 139 is Helmcol Yellow 2140 (manufactured by Hermeta), a specific example of Pigment Orange 61 is Irgazin Orange K2890 (manufactured by BASF), a specific example of Pigment Red 254 is Cromophtal Red 2028 (manufactured by BASF), a specific example of Pigment Red 264 is Irgazin DPP Rubin TR (manufactured by BASF), a specific example of Pigment Orange 71 is Cromophtal DPP Orange TRP (manufactured by BASF), a specific example of Pigment Green 7 is Fastgen Green S (manufactured by DIC), a specific example of Pigment Green 36 is Fastgen Green 2YK (manufactured by DIC),A specific example of Pigment Blue 15 is Fastogen Blue AR-7E (manufactured by DIC Corporation).

[0026] Examples of inorganic pigments include titanium oxide, calcium carbonate, barium sulfate, zinc sulfide, iron oxide, ultramarine, cobalt blue, nickel titanium yellow, bismuth yellow, carbon black, and pearl pigments. The inorganic pigments may or may not be surface-treated. Examples of surface treatments include aluminum oxide treatment, silicon dioxide treatment, siloxane treatment (also referred to as silicone treatment), and treatments combining two or more selected from these.

[0027] The content of Pigment 1 is, for example, 1 to 30% by mass, 1 to 25% by mass, 1 to 20% by mass, 1 to 10% by mass, 1 to 8% by mass, or 1 to 6% by mass, based on the inner layer (100% by mass of the inner layer). When the content is 1% by mass or more, the contents of the container tend to be sufficiently concealed. When the content is 10% by mass or less, the drop impact strength of the container can be better maintained.

[0028] The content of pigment 1a is, for example, 0.01 to 4.0% by mass, 0.05 to 2.0% by mass, or 0.1 to 1.2% by mass, based on the inner layer (per 100% by mass of the inner layer). The content of pigment 1b is, for example, 1 to 25% by mass, 1 to 20% by mass, 1 to 10% by mass, 1 to 8% by mass, or 1 to 6% by mass, based on the inner layer (per 100% by mass of the inner layer). When the content is 1% by mass or more, the contents of the container tend to be sufficiently concealed. When the content is 10% by mass or less, the drop impact strength of the container can be better maintained.

[0029] The content of the organic pigment is, for example, 0 to 5 mass%, 0 to 4 mass%, or 0 to 3 mass% based on the inner layer (100 mass% of the inner layer). When the content is 5 mass% or less, it is easy to maintain the appearance of the container white.

[0030] The content of the inorganic pigment is, for example, 1 to 25% by mass, 1 to 20% by mass, 1 to 10% by mass, 1 to 8% by mass, or 1 to 6% by mass, based on the inner layer (100% by mass of the inner layer). When the content is 1% by mass or more, the contents of the container tend to be sufficiently concealed. When the content is 10% by mass or less, the drop impact strength of the container can be better maintained.

[0031] Pigment 1 may contain white pigment 1. "White pigment 1" refers to a white pigment contained in the inner layer. Examples of embodiments in which pigment 1 contains white pigment 1 include (1) the inner layer contains pigment 1a, and pigment 1a contains white pigment 1, and (2) the inner layer contains pigment 1a and pigment 1b, and pigment 1a and pigment 1b contain white pigment 1. White pigment 1 preferably contains titanium oxide.

[0032] The content of the white pigment 1 is, for example, 1 to 25% by mass, 1 to 20% by mass, 1 to 10% by mass, 1 to 8% by mass, or 1 to 6% by mass, based on the inner layer (100% by mass of the inner layer). When the content is 1% by mass or more, the contents of the container tend to be sufficiently concealed. When the content is 10% by mass or less, the drop impact strength of the container can be better maintained.

[0033] When the white pigment 1 contains titanium oxide, the titanium oxide is preferably rutile-type titanium oxide, which has low catalytic activity, from the viewpoint of suppressing weather resistance. Furthermore, when the white pigment 1 contains rutile-type titanium oxide, good hiding power is likely to be obtained. From the viewpoint of hiding power, the average particle size of the titanium oxide is preferably 0.10 to 0.30 μm, 0.20 to 0.28 μm, or 0.22 to 0.25 μm. The average particle size refers to the volume-based median diameter (D50) in a dynamic light-scattering particle size distribution (based on scattered light intensity). The average particle size can be measured, for example, at 25°C using a dynamic light-scattering particle size distribution analyzer LB-550 (manufactured by Horiba, Ltd.).

[0034] For example, pigment 1 may contain aluminum oxide, silicon dioxide, and titanium oxide treated with siloxane. Titanium oxide is preferably used as a white pigment in the cap to provide hiding power, and it is more preferable that the cap be subjected to a surface treatment such as that described above to improve weather resistance and dispersibility in addition to hiding power. Furthermore, from the viewpoints of moldability and molded body strength, it is preferable to use a recycled resin composition obtained from a cap containing titanium oxide that has been subjected to such a surface treatment for the multilayer molded container. The presence or absence of surface-treated titanium oxide can be determined by methods such as ash content measurement according to JIS K7250-1:2006 and X-ray fluorescence analysis according to JIS K0119-1:2008. The content of the surface-treated titanium oxide is, for example, 0.05 to 10.00% by mass, 0.05 to 5.00% by mass, 0.10 to 3.00% by mass, or 0.10 to 2.00% by mass, based on the inner layer (100% by mass of the inner layer). When Pigment 1 contains surface-treated titanium oxide, from the viewpoint of hue, the content of the organic pigment is preferably 5.00 mass% or less, and more preferably 2.00 mass% or less, based on the inner layer (100 mass% of the inner layer). The organic pigment contained can be identified by gas chromatography mass spectrometry (GC / MS) as described in JIS K0123:2018.

[0035] [Resin 1] The inner layer may contain Resin 1. Resin 1 may be a resin used in molding a multilayer molded container, and is preferably a thermoplastic resin. Resin 1 may be a resin compatible with recycled resins, and examples of compatible resins include polyester, polystyrene, polyolefin, and aromatic nylon. Examples of polyolefins include polyethylenes such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE), polypropylene, ethylene-vinyl acetate copolymers, ethylene-α-olefin random copolymers, and ionomer resins. Resin 1 preferably contains a polyolefin, and more preferably contains polyethylene, polypropylene, or both.

[0036] The melt mass flow rate (MFR) of the resin 1 is preferably, for example, 0.01 to 50 g / 10 min, 0.1 to 2 g / 10 min, or 0.1 to 1 g / 10 min.

[0037] The content of Resin 1 is, for example, 10 to 80% by mass, 10 to 70% by mass, 10 to 50% by mass, 15 to 45% by mass, or 20 to 40% by mass, based on the inner layer (100% by mass of the inner layer). When the content is 10% by mass or more, good moldability can be maintained in blow molding or extrusion molding. When the content is 50% by mass or less, the amount of petroleum-derived resin can be reduced.

[0038] [Optional Components] The inner layer may contain optional components such as additives in addition to the resin 1, as necessary. Examples of additives include metal soaps such as alkali metals, alkaline earth metals, and zinc; antioxidants; ultraviolet absorbers; light stabilizers; metal deactivators; surfactants such as nonionic surfactants, cationic surfactants, anionic surfactants, and amphoteric surfactants; antistatic agents; and flame retardants such as halogen-based, phosphorus-based, and metal oxide-based flame retardants.

[0039] Examples of metallic soaps include calcium stearate, magnesium stearate, barium stearate, zinc stearate, aluminum stearate, lithium stearate, calcium laurate, zinc laurate, and magnesium laurate.

[0040] Examples of antioxidants include phenol-based and phosphite-based antioxidants. Examples of phenol-based antioxidants include diethyl [[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. Examples of phosphite-based antioxidants include tris(2,4-di-tert-butylphenyl)phosphite and bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol-diphosphite.

[0041] Examples of ultraviolet absorbers include benzotriazoles and triazines. Examples of benzotriazoles include 2,2-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6[(2H-benzotriazol-2-yl)phenol]], 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, and 2-[5-chloro(2H)-benzotriazol-2-yl]-4-methyl-6-(tert-butyl)phenol. Examples of triazines include 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol.

[0042] Examples of the light stabilizer include hindered amines. Examples of the hindered amines include bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}], and a polycondensate of dibutylamine, 1,3,5-triazine, N,N-bis(2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine, and N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine.

[0043] Examples of metal deactivators include 2,3-bis[[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyl]]propionohydrazide.

[0044] The content of the optional component is, for example, 0.01 to 5% by mass, 0.05 to 3% by mass, or 0.1 to 1% by mass based on the inner layer (100% by mass of the inner layer). When the content is 0.01% by mass or more, the effect of the added material can be fully exhibited. When the content is 5% by mass or less, molding can be performed while suppressing migration such as bleed-out.

[0045] <Outer Layer> The outer layer contains Pigment 2 and Resin 2. The outer layer may further contain optional components. The outer layer is a layer located outside the inner layer in a multilayer molded container. The outer layer may be a layer in contact with the inner layer, or may include an optional layer such as an adhesive layer or another resin layer between the outer layer and the inner layer, or may include an optional layer outside the outer layer. Examples of Pigment 2, Resin 2, and optional components are the same as the examples of Pigment 1, Resin 1, and optional components in the description of the inner layer.

[0046] [Pigment 2] The outer layer contains pigment 2. Examples of pigment 2 include organic pigments and inorganic pigments. Examples of organic pigments and inorganic pigments are the same as the examples of organic pigments and inorganic pigments in the description of the inner layer.

[0047] The content of pigment 2 is, for example, 2 to 20% by mass, 3 to 15% by mass, or 5 to 10% by mass, based on the outer layer (100% by mass of the outer layer). When the content is 2% by mass or more, the inner layer can be sufficiently concealed, thereby maintaining a good appearance. When the content is 20% by mass or less, good moldability can be maintained in blow molding or extrusion molding.

[0048] The content of the organic pigment is, for example, 0 to 3 mass%, 0.1 to 3 mass%, 0.2 to 2 mass%, or 0.3 to 1 mass%, based on the outer layer (100 mass% of the outer layer). If it is 0.1 mass% or more, a vivid appearance tends to be maintained. If it is 3 mass% or less, elution into the contents can be suppressed.

[0049] The content of the inorganic pigment is, for example, 2 to 20% by mass, 3 to 15% by mass, or 5 to 10% by mass, based on the outer layer (100% by mass of the outer layer). If the content is 2% by mass or more, the inner layer can be sufficiently concealed, and therefore a good appearance tends to be maintained. If the content is 20% by mass or less, good moldability can be maintained in blow molding or extrusion molding.

[0050] Pigment 2 may contain white pigment 2. "White pigment 2" refers to the white pigment contained in the outer layer. The content of white pigment 2 is, for example, 2 to 20 mass%, 3 to 15 mass%, or 5 to 10 mass% based on the outer layer (outer layer 100 mass%). When the content is 2 mass% or more, the inner layer tends to be sufficiently hidden and a good white appearance tends to be maintained. When the content is 20 mass% or less, good moldability can be maintained in blow molding or extrusion molding. White pigment 2 preferably contains titanium oxide.

[0051] [Resin 2] The outer layer contains Resin 2. Resin 2 may be a resin used in molding a multilayer molded container, and is preferably a thermoplastic resin. Resin 2 preferably contains a polyolefin, and more preferably contains polyethylene, polypropylene, or both. Examples of thermoplastic resins and polyolefins are the same as the examples of thermoplastic resins and polyolefins described for the inner layer.

[0052] The content of Resin 2 is, for example, 80 to 98% by mass, 85 to 97% by mass, or 90 to 95% by mass, based on the outer layer (100% by mass of the outer layer). When the content is 80% by mass or more, good moldability can be maintained in blow molding or extrusion molding. When the content is 98% by mass or less, the inner layer can be sufficiently concealed, and therefore a good appearance tends to be maintained.

[0053] <Multilayer structure> The multilayer molded container has a multilayer structure. Examples of the multilayer structure are as follows: - inner layer / outer layer - inner layer / adhesive layer / outer layer - resin layer X / inner layer / outer layer - inner layer / outer layer / resin layer X - resin layer X / adhesive layer / inner layer / adhesive layer / outer layer - resin layer X / inner layer / resin layer Y / outer layer - resin layer X / inner layer / outer layer / resin layer Y - resin layer X / adhesive layer / inner layer / adhesive layer / resin layer Y / adhesive layer / outer layer - resin layer X / resin layer Y / inner layer / outer layer - resin layer X / adhesive layer / resin layer Y / adhesive layer / inner layer / adhesive layer / outer layer

[0054] The adhesive layer is a layer that bonds two or more layers together, and may be a layer for bonding two layers that have different melting points, for example. Known adhesive layers include layers formed using adhesives containing acid-modified polyolefins, ethylene-acrylic acid copolymer resins, ethylene-vinyl acetate copolymer resins, and the like. Examples of commercially available adhesives include Nucrel (manufactured by DuPont-Mitsui Polychemicals), Admer (manufactured by Mitsui Chemicals, Inc.), and Mersen (manufactured by Tosoh Corporation).

[0055] Resin layer X and resin layer Y are layers having various functions, such as an innermost layer to prevent direct contact between the contents and the inner layer containing recycled material, a barrier layer, an outermost layer provided outside the outer layer to increase the smoothness of the container surface and further improve the design, etc. For example, resin layer X and resin layer Y may each independently be a layer having the same composition as the inner layer or outer layer.

[0056] <Shape, Uses, etc.> The shape of the multilayer molded container may be any shape, such as a bottle, a tube, a cylinder, a prism, or a sphere. A bottle or tube shape is preferred. According to an embodiment of the present invention, a bottle or a tube is obtained as a multilayer molded container. The capacity of the multilayer molded container is not particularly limited and may be any capacity, such as 350 mL, 500 mL, 1000 mL, 1500 mL, or 2000 mL. The thickness of the entire multilayer molded container may be uniform or non-uniform. For example, when the multilayer molded container is a bottle, the thicknesses of the neck, shoulder, body, bottom, etc. of the bottle may be different from one another. The multilayer molded container may have a multilayer structure having an inner layer and an outer layer in at least a portion thereof. The multilayer molded container may have a multilayer structure throughout the entire container, or may have a multilayer structure in a portion of the container, with the remaining portion having a single layer or another laminate structure.

[0057] The multilayer molded container is suitable for various uses such as for detergents, cosmetics, medicines, foods, medical products, etc. The multilayer molded container is preferably a detergent bottle or a detergent tube.

[0058] <Lightness and Yellowness> The lightness (L* value) of at least a portion of the surface of the multilayer molded container may be 80.0 to 99.0. The lightness (L* value) is the L* value in the L*a*b* color system defined by the International Commission on Illumination (CIE) and can be measured using a colorimeter. The lightness (L* value) is preferably 85.0 to 99.0, or 90.0 to 99.0. The lightness (L* value) can be adjusted by the lightness, thickness, etc. of the outer and inner layers. When the multilayer molded container is a bottle or a tube, it is preferable that the lightness of at least the body portion satisfies the above range, and it is more preferable that the lightness of the entire bottle or tube satisfies the above range.

[0059] The multilayer molded container may have a yellowness index (YI value) of -15.0 to 15.0 on at least a portion of its surface. The yellowness index (YI value) is determined in accordance with JIS K 7373:2006 based on the XYZ color system defined by the International Commission on Illumination (CIE), and can be measured using a color difference meter. The yellowness index (YI value) is preferably -10.0 to 10.0, or -5.0 to 5.0. The yellowness index (YI value) can be adjusted by the hue, thickness, etc. of the outer and inner layers. When the multilayer molded container is a bottle or a tube, it is preferable that the yellowness index of at least the body portion satisfies the above range, and it is more preferable that the yellowness index of the entire bottle or tube satisfies the above range.

[0060] <Total Light Transmittance> The multilayer molded container may have a total light transmittance of 10.0% or less at least in part. The total light transmittance is preferably 5.0% or less, or 1.0% or less. The total light transmittance can be adjusted by the total light transmittances and thicknesses of the outer and inner layers. When the multilayer molded container is a bottle or a tube, it is preferable that the total light transmittance of at least the body portion satisfies the above range, and it is more preferable that the total light transmittance of the entire bottle or tube satisfies the above range.

[0061] <Thickness> For example, the multilayer molded container has at least an inner layer and an outer layer, and at least a part of the multilayer molded container has a multilayer structure in which the inner layer has a thickness of 300 to 2,500 μm and the outer layer has a thickness of 50 to 1,000 μm. The multilayer molded container may entirely have a multilayer structure in which the inner and outer layers have thicknesses within the above ranges.

[0062] When the container is a bottle, the overall thickness of the multilayer structure may be 500 to 3,000 μm, 700 to 2,500 μm, or 900 to 1,500 μm. A thickness of 500 μm or more allows the strength of the bottle to be maintained. A thickness of 3,000 μm or less allows uniform blow molding. It is preferable that the thickness of at least a portion of the multilayer structure of the bottle falls within the above range, and more preferably that the thickness of the entire multilayer structure of the bottle falls within the above range. Similarly, it is preferable that a portion of the thickness of the inner layer, the thickness of the outer layer, and the thickness ratio of the inner layer to the outer layer each fall within the following range, and more preferably that the entire thickness falls within the following range. The thickness of the inner layer is, for example, 300 to 2,500 μm, 500 to 2,000 μm, or 700 to 1,500 μm. A thickness of 300 μm or more allows the strength of the bottle to be maintained. A thickness of 2,500 μm or less allows uniform blow molding. The thickness of the outer layer is, for example, 50 to 1,000 μm, 60 to 500 μm, or 70 to 200 μm. When the thickness is 50 μm or more, the inner layer can be sufficiently concealed. When the thickness is 1,000 μm or less, uniform blow molding can be achieved. The ratio of inner layer thickness to outer layer thickness is, for example, 20 / 1 to 1 / 1, 15 / 1 to 3 / 1, or 12 / 1 to 5 / 1.

[0063] In the case of a tube, the overall thickness of the laminate structure may be 100 to 1,000 μm, 150 to 800 μm, or 200 to 600 μm. When the thickness is 100 μm or more, the strength of the tube can be maintained. When the thickness is 1,000 μm or less, a lightweight tube can be held. The thickness of the inner layer is, for example, 40 to 800 μm, 80 to 500 μm, or 100 to 300 μm. When the thickness is 40 μm or more, the strength of the tube can be maintained. When the thickness is 800 μm or less, a lightweight tube can be held. The thickness of the outer layer is, for example, 20 to 500 μm, 40 to 300 μm, or 60 to 200 μm. When the thickness is 20 μm or more, the inner layer can be sufficiently concealed. When the thickness is 500 μm or less, a lightweight tube can be held. The ratio of the thickness of the inner layer to the thickness of the outer layer is, for example, 10 / 1 to 1 / 2, 5 / 1 to 1 / 1, or 3 / 1 to 1 / 1.

[0064] The thickness of the adhesive layer is, for example, 10 to 100 μm. The thickness of the resin layer X may be a thickness suitable for the function, material, etc. of the resin layer X, and is, for example, 50 to 1,000 μm. The thickness of the resin layer Y may be a thickness suitable for the function, material, etc. of the resin layer Y, and is, for example, 50 to 1,000 μm.

[0065] <Recycled Resin Composition> The recycled resin composition according to an embodiment of the present invention is obtained by recycling a PET bottle cap. The recycled resin composition contains at least a recycled resin and a pigment 1a, and may further contain optional components. The recycled resin, pigment 1a, and optional components are as described above. The optional components may be additives contained in the PET bottle cap. The recycled resin composition may be in the form of, for example, pellets, powder, or granules, and is preferably in the form of pellets. The recycled resin composition is used to manufacture the multilayer molded container according to the embodiment described above.

[0066] The recycled resin content is, for example, 90.0 to 99.9% by mass, 95.0 to 99.8% by mass, or 98.0 to 99.5% by mass based on the recycled resin composition (100% by mass of the recycled resin composition). When the recycled resin content is 90.0% by mass or more, the amount of petroleum-derived resin can be reduced. When the recycled resin content is 99.9% by mass or less, the contents of the container are concealed, thereby maintaining a good appearance.

[0067] The content of pigment 1a is, for example, 0.01 to 10.00% by mass, 0.05 to 5.00% by mass, or 0.10 to 2.00% by mass, based on the recycled resin composition (100% by mass of the recycled resin composition). When the content is 0.01% by mass or more, the contents are concealed, thereby maintaining a good appearance. When the content is 10.00% by mass or less, good moldability can be maintained in blow molding or extrusion molding. The content of organic pigment is, for example, 0 to 1% by mass, 0.001 to 1.00% by mass, or 0.01 to 0.50% by mass. The content of inorganic pigment is, for example, 0.00 to 10.00% by mass, 0.05 to 5.00% by mass, or 0.10 to 2.00% by mass.

[0068] The recycled resin composition can be obtained, for example, by a production method including crushing PET bottle caps to obtain a crushed product (crushing step), and melt-kneading the crushed product to obtain a kneaded product (kneading step). The production method may further include optional steps such as washing the PET bottle caps, drying the washed PET bottle caps, washing the crushed product, drying the washed crushed product, separating the crushed product, adding optional components, and molding the kneaded product into a shape such as pellets.

[0069] The method for crushing the packaging material in the crushing step is not particularly limited, and examples thereof include methods using a jaw crusher, impact crusher, cutter mill, stamp mill, ring mill, roller mill, jet mill, and hammer mill.

[0070] In the kneading step, any component such as an additive may be added as necessary. The melt-kneading method is not particularly limited, and examples thereof include a method in which the components are mixed using a Henschel mixer, a tumbler, a disper, or the like, and then melt-kneaded using a batch mixer such as a kneader, a roll mill, a super mixer, a Henschel mixer, a Schuggie mixer, a vertical granulator, a high-speed mixer, a Farmatrix, a ball mill, a steel mill, a sand mill, a vibration mill, an attritor, or a Banbury mixer, a twin-screw extruder, a single-screw extruder, or a rotor-type twin-screw kneader. When the kneaded product is granulated into a shape such as pellets, a twin-screw extruder or a single-screw extruder can be preferably used.

[0071] <<Method for Manufacturing a Multilayer Molded Container>> A method for manufacturing a multilayer molded container according to an embodiment of the present invention includes molding an inner layer material containing a recycled resin obtained from PET bottle caps and pigment 1, and an outer layer material containing white pigment 2 and resin 2, by blow molding or extrusion molding. The blow molding method may be, for example, injection blow molding, and the extrusion molding method may be, for example, co-extrusion molding. The inner layer material may further contain resin 1. The outer layer material may further contain a pigment other than white pigment 2. The recycled resin, pigment 1 (pigment 1a, pigment 1b), resin 1, pigment 2 (white pigment 2), resin 2, and optional components that can be used in the method for manufacturing a multilayer molded container are as described above.

[0072] The method for producing a multilayer molded container may include molding an inner layer and / or an outer layer that satisfies at least one of the following (1) to (4): (1) When a laminate consisting of the inner layer and the outer layer is formed, the lightness (L* value) measured from the outer layer side is 80.0 to 99.0, 85.0 to 99.0, or 90.0 to 99.0. (2) When a laminate consisting of the inner layer and the outer layer is formed, the yellowness (YI value) measured from the outer layer side is -15.0 to 15.0, -10.0 to 10.0, or -5.0 to 5.0. (3) The lightness (L* value) of the inner layer is 45.0 to 90.0, 70.0 to 85.0, or 75.0 to 82.0. (4) The total light transmittance of the outer layer is 90.0% or less, 60.0% or less, or 35.0% or less.

[0073] The lightness, yellowness index, and total light transmittance can be adjusted by changing the types of inner layer and outer layer materials, the thicknesses of the inner and outer layers, etc. Furthermore, the lightness, yellowness index, and total light transmittance values ​​in (1) to (4) above can be measured by using the same inner layer and outer layer materials as in the case of producing a multilayer molded container according to the method for producing a multilayer molded container of an embodiment of the present invention, producing an inner layer, an outer layer, or a laminate comprising these, having the same thickness as in the case of producing a multilayer molded container according to the method for producing a multilayer molded container of an embodiment of the present invention, and using the produced inner layer, outer layer, or laminate comprising these. The production method in this case may be, for example, a method using a film molding machine or a method using a heat press.

[0074] Preferred combinations of inner and outer layers include the following: An inner layer having a brightness (L* value) of 45.0 to 85.0 and an outer layer having a total light transmittance of less than 35.0% An inner layer having a brightness (L* value) of 75.0 to 90.0 and an outer layer having a total light transmittance of 35.0 to 40.0%

[0075] <Inner Layer Material and Outer Layer Material> The material for the inner layer (sometimes referred to as the "inner layer material") can be prepared by kneading a recycled resin composition containing a recycled resin and a pigment 1a with, as needed, resin 1, pigment 1b, and any other components. The material for the outer layer (sometimes referred to as the "outer layer material") can be prepared by kneading a white pigment 2, resin 2, and, as needed, any other components.

[0076] The inner layer material and the outer layer material may be materials that satisfy at least one of the following (1) to (6): (1) The MFR of a 1,000 μm-thick layer 1 formed using the inner layer material is 0.05 to 5 g / 10 min. (2) The MFR of a 100 μm-thick layer 2 formed using the outer layer material is 0.05 to 5 g / 10 min. (3) The lightness (L* value) measured from the layer 2 side of a laminate consisting of a 1,000 μm-thick layer 1 formed using the inner layer material and a 100 μm-thick layer 2 formed using the outer layer material is 80.0 to 99.0, 85.0 to 99.0, or 90.0 to 99.0. (4) A laminate consisting of a 1,000 μm thick layer 1 formed using an inner layer material and a 100 μm thick layer 2 formed using an outer layer material has a yellowness index (YI value) measured from the layer 2 side of -15.0 to 15.0, -10.0 to 10.0, or -5.0 to 5.0. (5) The 1,000 μm thick layer 1 formed using the inner layer material has a lightness (L* value) of 45.0 to 90.0, 70.0 to 85.0, or 75.0 to 82.0. (6) The 100 μm thick layer 2 formed using the outer layer material has a total light transmittance of 90.0% or less, 60.0% or less, or 35.0% or less.

[0077] The MFR of the inner layer material can be adjusted by changing the type and content of Resin 1 and the content of Pigment 1. The MFR of the outer layer material can be adjusted by changing the type and content of Resin 2 and the content of Pigment 2. The lightness, yellowness index, and total light transmittance can be adjusted by changing the type and content of the pigment contained in each layer.

[0078] Preferred combinations of inner layer materials and outer layer materials include the following: An inner layer material in which the brightness (L* value) of layer 1 is 45.0 to 85.0, and an outer layer material in which the total light transmittance of layer 2 is less than 35.0%. An inner layer material in which the brightness (L* value) of layer 1 is 75.0 to 90.0, and an outer layer material in which the total light transmittance of layer 2 is 35.0 to 40.0%.

[0079] MFR can be determined in accordance with JIS K 7210:-1:2014. Total light transmittance can be measured in accordance with JIS K 7375:2008. Lightness (L* value) is the L* value in the L*a*b* color system defined by the International Commission on Illumination (CIE) and can be measured using a colorimeter. Yellowness index (YI value) is the YI value determined in accordance with JIS K 7373:2006 based on the XYZ color system defined by the International Commission on Illumination (CIE) and can be measured using a colorimeter.

[0080] The amounts of recycled resin obtained using PET bottle caps, pigment 1, optionally used resin 1, white pigment 2, and resin 2 used may be amounts that result in the content rates described in the description of the inner layer and outer layer of the multilayer molded container of the above embodiment.

[0081] Examples of embodiments are given below: The embodiments of the present invention are not limited to the following.

[0082] (1) A multilayer molded container having at least an inner layer containing a recycled resin obtained using a PET bottle cap and pigment 1, and an outer layer containing white pigment 2 and resin 2. (2) A multilayer molded container having at least an inner layer containing a recycled resin composition obtained using a PET bottle cap and an outer layer containing white pigment 2 and resin 2, wherein the recycled resin composition contains the recycled resin obtained using the PET bottle cap and pigment 1a derived from the PET bottle cap, and has a melt mass flow rate (MFR) of 2 to 10 g / 10 min. (3) A multilayer molded container having at least an inner layer containing a recycled resin obtained using a PET bottle cap and pigment 1, and an outer layer containing white pigment 2 and resin 2, wherein the inner layer is obtained using a recycled resin composition, wherein the recycled resin composition has a melt mass flow rate (MFR) of 0.1 to 10 g / 10 min and a density of 930 to 970 kg / m ３(4) A multilayer molded container having at least an inner layer containing a recycled resin obtained using PET bottle caps and pigment 1, and an outer layer containing a white pigment 2 and resin 2, wherein the recycled resin contains polyethylene and polypropylene, and the ratio of the mass (g) of polyethylene to the mass (g) of polypropylene in the recycled resin is 80-90:10-20. (5) A multilayer molded container having at least an inner layer containing a recycled resin obtained using PET bottle caps and pigment 1, and an outer layer containing a white pigment 2 and resin 2, wherein the recycled resin contains polyethylene and polypropylene, and the ratio of the mass (g) of polyethylene to the mass (g) of polypropylene in the recycled resin is 70-95:5-30. The ratio of the mass (g) of polyethylene to the mass (g) of polypropylene may be 70-95:5-30 (excluding the ratio 80-90:10-20). (6) A multilayer molded container having at least an inner layer containing a recycled resin obtained using a PET bottle cap and pigment 1, and an outer layer containing a white pigment 2 and resin 2, wherein the pigment 1 comprises at least one pigment selected from the group consisting of Pigment Yellow 181 and Pigment Red 254. (7) A multilayer molded container having at least an inner layer containing a recycled resin obtained using a PET bottle cap and pigment 1, and an outer layer containing a white pigment 2 and resin 2, wherein the pigment 1 comprises at least one pigment selected from the group consisting of monoazo yellow, disazo yellow, monoazo orange, quinacridone red, diketopyrrolopyrrole red, phthalocyanine green, phthalocyanine blue, and quinacridone violet. The pigment 1 may include at least one selected from the group consisting of monoazo yellow, disazo yellow, monoazo orange, quinacridone red, diketopyrrolopyrrole red, phthalocyanine green, phthalocyanine blue, and quinacridone violet (excluding Pigment Yellow 181 and Pigment Red 254).

[0083] (8) The multilayer molded container according to any one of (1) to (7), wherein the recycled resin comprises at least one selected from the group consisting of polyethylene and polypropylene. (9) The multilayer molded container according to any one of (1) to (8), wherein the inner layer further comprises resin 1, and resin 1 and resin 2 comprise polyolefin. (10) The multilayer molded container according to any one of (1) to (9), wherein the white pigment 2 comprises titanium oxide. (11) The multilayer molded container according to any one of (1) to (10), wherein the content of white pigment 2 is 2 to 20 mass% based on the outer layer. (12) The multilayer molded container according to any one of (1) to (11), wherein the content of pigment 1 comprises white pigment 1. (13) The multilayer molded container according to (12), wherein the white pigment 1 comprises titanium oxide. (14) The multilayer molded container according to (12) or (13), wherein the content of white pigment 1 is 1 to 25 mass% based on the inner layer. (15) The multilayer molded container according to any one of (1) to (14), at least partially having a multilayer structure having at least the inner layer and the outer layer, the inner layer having a thickness of 300 to 2,500 μm and the outer layer having a thickness of 50 to 1,000 μm. (16) The multilayer molded container according to any one of (1) to (15), at least a portion of which has a lightness (L* value) of 80.0 to 99.0 on its surface. (17) A bottle which is the multilayer molded container according to any one of (1) to (16). (18) A tube which is the multilayer molded container according to any one of (1) to (16). (19) A recycled resin composition used in the production of the multilayer molded container according to any one of (1) to (16), comprising recycled resin obtained from PET bottle caps and pigment 1.

[0084] (20) A method for producing a multilayer molded container, comprising: molding, by blow molding or extrusion molding, an inner layer material containing recycled resin obtained from PET bottle caps and pigment 1; and an outer layer material containing white pigment 2 and resin 2. The multilayer molded container may be the multilayer molded container described in any one of (1) to (16) above. (21) A method for producing a multilayer molded container having an inner layer containing recycled resin obtained from PET bottle caps and pigment 1, and an outer layer containing white pigment 2 and resin 2, the method comprising: molding, by blow molding or extrusion molding, an inner layer material containing the recycled resin composition described in (19) above, and an outer layer material containing white pigment 2 and resin 2. The multilayer molded container may be the multilayer molded container described in any one of (1) to (16) above. (22) The method for producing a multilayer molded container described in (20) or (21) above, in which the inner layer material further contains resin 1. (23) A method for producing a multilayer molded container according to any one of (20) to (22) above, wherein an inner layer and an outer layer that satisfy the following are molded. When a laminate consisting of the inner layer and the outer layer is formed, the lightness (L* value) measured from the outer layer side is 80.0 to 99.0. (24) A method for producing a multilayer molded container according to any one of (20) to (23) above, wherein an inner layer that satisfies the following is molded. The lightness (L* value) of the inner layer is 45.0 to 90.0. (25) A method for producing a multilayer molded container according to any one of (20) to (24) above, wherein an outer layer that satisfies the following is molded. The total light transmittance of the outer layer is 90.0% or less.

[0085] The disclosure of this application is related to the subject matter described in Japanese Patent Application No. 2024-66367 filed on April 16, 2024 and Japanese Patent Application No. 2024-204260 filed on November 22, 2024, the entire disclosures of which are incorporated herein by reference.

[0086] The embodiments of the present invention will be described below with reference to examples, but the embodiments of the present invention are not limited to the following examples.

[0087] Example I Preparation of Inner Layer Material and Outer Layer Material The following raw materials for the inner layer material and outer layer material were prepared. Recycled Resin Composition Derived from PET Bottle Caps PET bottle caps were crushed, and the crushed material was melt-kneaded to obtain a pellet-shaped recycled resin composition containing the recycled resin and pigment 1a. The composition and MFR of the recycled resin composition are as follows: Mass (g) of polyethylene: Mass (g) of polypropylene = 80:20 Content of pigment 1a: 0.50% by mass MFR: 5 g / 10 min <Resin 1 (A)> (A-1) HDPE (Hi-Zex 6203B, manufactured by Prime Polymer Co., Ltd., MFR: 0.35 g / 10 min) (A-2) LLDPE (Neo-Zex 2006H, manufactured by Prime Polymer Co., Ltd., MFR: 0.63 g / 10 min) (A-3) LDPE (Petrothene 170K, manufactured by Tosoh Corporation, MFR: 1.0 g / 10 min) <Pigment 1b (B)> (B-1) Titanium oxide (Tipake PF-711, manufactured by Ishihara Sangyo Kaisha, Ltd., average particle size: 0.25 μm) (B-2) Heavy calcium carbonate (Whiten-H, manufactured by Shiraishi Calcium Co., Ltd., average particle size: 22 μm) (B-3) Zinc sulfide (Sactris HD-S manufactured by Benatar, average particle size: 0.30 μm)

[0088] <Resin 2> (C-1) HDPE (Hi-Zex 6203B, manufactured by Prime Polymer Co., Ltd., MFR: 0.35 g / 10 min) <Pigment 2> (D-1) Titanium oxide (Tipake PF-711, manufactured by Ishihara Sangyo Kaisha, Ltd., average particle size: 0.25 μm)

[0089] [Inner layer composition 1] Resin 1 (A-1) and a recycled resin composition derived from PET bottle caps were fed into a twin-screw extruder (manufactured by The Japan Steel Works, Ltd.) from separate feed ports so that the total weight of Resin 1 (A-1) was 50% by mass and the recycled resin composition derived from PET bottle caps was 50% by mass, and the mixture was melt-kneaded at 220°C to obtain inner layer composition 1, a pellet-shaped polyethylene-based inner layer material.

[0090] [Inner layer compositions 2 to 16] Inner layer compositions were produced in the same manner as inner layer composition 1, except that the types and blending amounts (mass%) of Resin 1 (A), Pigment 1b (B), and the recycled resin composition derived from PET bottle caps were changed as shown in Table 1.

[0091] A 1,000 μm thick pressed sheet was prepared using the inner layer composition at 200° C. using a heat press machine, and the color was measured. A vernier caliper was used to measure the film thickness, and a color difference meter (SpectroColorMeter SE2000, manufactured by Nippon Denshoku Industries Co., Ltd.) was used to measure the color.

[0092]

[0093] [Outer Layer Material 1] 100% by mass of Resin 2 (C-1) was prepared as outer layer material 1.

[0094] [Outer Layer Composition 2] Resin (C-1) and pigment (D-1) were fed into a twin-screw extruder (manufactured by The Japan Steel Works, Ltd.) from separate feed ports so that the composition was 97% by mass of resin 2 (C-1) and 3% by mass of pigment 2 (D-1), and the mixture was melt-kneaded at 220°C to obtain outer layer composition 2, a pellet-like polyethylene-based outer layer material.

[0095] [Outer Layer Compositions 3 to 6] Outer layer compositions were produced in the same manner as for Outer Layer Composition 2, except that the blending amounts (mass%) of Resin 2 (C-1) and Pigment 2 (D-1) were changed as shown in Table 2.

[0096] Using the outer layer composition, a film having a thickness of 100 μm was produced at a temperature of 200° C. using a film forming machine, and the total light transmittance was measured. The film thickness was measured using a vernier caliper, and the total light transmittance was measured using a haze meter (Hazeguard Plus, manufactured by BYK Corporation).

[0097]

[0098] <<Production and Evaluation of Multilayer Molded Containers>> Multilayer molded containers were produced using the inner layer materials (inner layer compositions 1 to 16) and outer layer materials (outer layer compositions 1 to 6).

[0099] Example 1 A blow-molded container having a polyolefin-based multilayer structure was produced by direct blow molding at a temperature of 280°C using an inner layer composition 1 and an outer layer composition 2 in a direct multilayer blow molding machine (manufactured by Nissei ASB Co., Ltd.) The blow-molded container had a cylindrical bottle shape with a capacity of 500 mL and a body diameter of 70 mm, and was molded so that the total thickness at the center of the body (near the center between the shoulder and bottom of the container) was 1,100 μm, the thickness of the inner layer was 1,000 μm, and the thickness of the outer layer was 100 μm.

[0100] Examples 2 to 28, Comparative Examples 1 to 6, and Reference Example 1 Blow-molded containers having a polyolefin-based multilayer structure were produced in the same manner as in Example 1, except that the types and layer configurations of the inner layer composition and outer layer composition were changed as shown in Table 3. Example 29 A blow-molded container having a polyolefin-based multilayer structure was produced in the same manner as in Example 23, except that the multilayer structure was inner layer / adhesive layer / outer layer, and a modified polyolefin (Admer NF518, manufactured by Mitsui Chemicals, Inc.) was used as the adhesive layer. Molding was performed so that the adhesive layer had a thickness of 20 μm at the center of the body. Example 30 A blow-molded container having a polyolefin-based multilayer structure was produced in the same manner as in Example 23, except that the multilayer structure was resin layer X / inner layer / outer layer, and the resin layer X was HDPE (Hi-Zex 6008B, manufactured by Prime Polymer Co., Ltd.). Molding was performed so that the resin layer X had a thickness of 100 μm at the center of the body.

[0101] The multilayer molded containers obtained in Examples 1 to 30, Comparative Examples 1 to 6, and Reference Example 1 were evaluated according to the following criteria, and the evaluation results are shown in Tables 3 and 4.

[0102] [Moldability] Three 3 cm square pieces were cut out from the center of the body of the multilayer molded container, and the thickness was measured with a vernier caliper. The difference between the maximum and minimum values ​​was taken as the thickness unevenness and evaluated according to the following criteria: ○: Thickness unevenness is less than 50 μm △: Thickness unevenness is 50 μm or more but less than 100 μm ×: Thickness unevenness is 100 μm or more

[0103] [Color as seen from the outside] A 3 cm square was cut out from the center of the body of the multilayer molded container, and the color was measured using a color difference meter (SpectroColorMeter SE2000, manufactured by Nippon Denshoku Industries Co., Ltd.) to measure the L* value and YI value, and the color was evaluated according to the following criteria: (L* value) ○: 90.0 or more △: 80.0 or more and less than 90.0 ×: Less than 80.0 (YI value) ○: Less than 10.0 △: 10.0 or more and less than 15.0 ×: 15.0 or more

[0104] [Concealing property] A 3 cm square was cut out from the center of the body of the multilayer molded container, and the total light transmittance was measured using a haze meter (Hazeguard Plus, manufactured by BYK Corporation) and evaluated according to the following criteria: ○: Less than 1.0% △: 1.0% or more and less than 10.0% ×: 10.0% or more

[0105] [Drop Strength] A multilayer molded container was filled with water, sealed, and dropped twice from a height of 1 m onto a concrete floor, once so that the bottom part touched the floor and once so that the body part touched the floor, and the drop strength was evaluated according to the following criteria: ○: No cracks or breaks occurred, and no leakage of contents was observed △: No leakage of contents was observed, but cracks or breaks occurred ×: Cracks or breaks occurred, and leakage of contents was observed

[0106] [Recycled Resin Composition Content] The recycled resin composition content (mass%) in the inner layer material was calculated according to the following formula and evaluated according to the following criteria: Recycled Resin Composition Content (mass%) = (Recycled Resin Composition Mass (g)) / (Recycled Resin Composition Mass (g) + Resin 1 Mass (g) + Pigment 1b Mass (g)) x 100 ○: 50 mass% or more △: 10 mass% or more and less than 50 mass% ×: Less than 10 mass%

[0107]

[0108]

[0109] Example II Preparation of Inner Layer Material The following raw materials were prepared for the inner layer material. Recycled Resin Composition Derived from PET Bottle Caps Crushed PET bottle caps purchased from a recycler were subjected to gravity separation to remove foreign matter, such as tiny fragments of polyethylene terephthalate (PET), followed by washing and dehydration to obtain a crushed recycled resin containing polyethylene (PE) and polypropylene (PP). The PE and PP composition ratios in the recycled resin in the crushed product vary depending on the time and region of cap collection. The composition ratios can be determined from the peak intensities of PE and PP using infrared spectroscopy analysis in accordance with JIS K0117:2017. For example, by adjusting the belt conveyor speed and recognition sensitivity using a resin sorter, AeroSorter III (manufactured by Daio Engineering Co., Ltd.), crushed products with any desired PE and PP composition ratio can be obtained. The pigment contained in the pulverized material can be identified by ash content measurement in accordance with JIS K7250-1:2006, X-ray fluorescence analysis in accordance with JIS K0119-1:2008, and gas chromatography-mass spectrometry (GC / MS) in accordance with JIS K0123:2018. The pulverized material separated according to composition ratio was melt-kneaded in a single-screw extruder (manufactured by Nippon Placo Co., Ltd.) and then fed into a pelletizer to obtain pelletized recycled resin compositions 1 to 21 containing recycled resin and pigment 1a. In recycled resin compositions 1 to 21, pigment 1a contained an inorganic pigment containing titanium oxide and multiple organic pigments selected from the group consisting of monoazo yellow, disazo yellow, monoazo orange, quinacridone red, diketopyrrolopyrrole red, phthalocyanine green, phthalocyanine blue, and quinacridone violet. In the recycled resin compositions 1 to 21, the pigment 1a contained at least one selected from the group consisting of pigment yellow 181 and pigment red 254. In the recycled resin compositions 1 to 21, the content of pigment 1a was 0.1 to 5 mass% based on the recycled resin composition. The composition, MFR, and density of the recycled resin compositions 1 to 21 are shown in Table 5.

[0110]

[0111] <Resin 1 (A)> (A-1) HDPE (Hi-Zex 6203B, manufactured by Prime Polymer Co., Ltd., MFR: 0.35 g / 10 min) <Pigment 1b (B)> (B-1) Titanium oxide (Tipake PF-711, manufactured by Ishihara Sangyo Kaisha, Ltd., average particle size: 0.25 μm, surface treatment: treatment with aluminum oxide, silicon dioxide, and siloxane) (B-4) Titanium oxide (CR-80, manufactured by Ishihara Sangyo Kaisha, Ltd., average particle size: 0.25 μm, surface treatment: treatment with aluminum oxide and silicon dioxide) (B-5) Titanium oxide (D-962, manufactured by Sakai Chemical Industry Co., Ltd., average particle size: 0.26 μm, surface treatment: treatment with aluminum oxide and siloxane)

[0112] [Inner layer composition 17] Resin 1 (A-1), Pigment 1b (B-1), and recycled resin composition 1 derived from PET bottle caps were fed into a twin-screw extruder (manufactured by The Japan Steel Works, Ltd.) from separate feed ports so as to give a mixture of 47% by mass of Resin 1 (A-1), 3% by mass of Pigment 1b (B-1), and 50% by mass of a recycled resin composition derived from PET bottle caps. The mixture was melt-kneaded at 220°C to obtain inner layer composition 17, a pellet-shaped polyethylene-based inner layer material.

[0113] [Inner layer compositions 18 to 42] Inner layer compositions were produced in the same manner as inner layer composition 17, except that the types and blending amounts (mass%) of Resin 1 (A), Pigment 1b (B), and the recycled resin composition derived from PET bottle caps were changed as shown in Table 6.

[0114] A press sheet was prepared using the inner layer composition in the same manner as in Example I, and the color was measured.

[0115]

[0116] <<Production and Evaluation of Multilayer Molded Containers>> Multilayer molded containers were produced using the inner layer materials (inner layer compositions 17 to 42) and the outer layer materials produced in Example I (outer layer compositions 1 and 2).

[0117] [Examples 31 to 56 and Comparative Examples 7 to 13] Blow-molded containers having a polyolefin-based multilayer structure were produced in the same manner as in Example I, except that the types and layer structures of the inner layer composition and outer layer composition were changed as shown in Tables 7 and 8, respectively.

[0118] The multilayer molded containers obtained in Examples 31 to 56 and Comparative Examples 7 to 13 were evaluated according to the same criteria as in Example I, and the evaluation results are shown in Tables 7 and 8.

[0119]

[0120]

Claims

1. A multi-layer molded container having at least an inner layer containing recycled resin obtained from PET bottle caps and pigment 1, and an outer layer containing white pigment 2 and resin 2.

2. The multilayer molded container according to claim 1, wherein the inner layer contains a recycled resin composition, the recycled resin composition contains a recycled resin obtained using PET bottle caps and a pigment 1a derived from PET bottle caps, and the melt mass flow rate (MFR) is 0.1 to 10 g / 10 min.

3. The inner layer is obtained using a recycled resin composition, and the recycled resin composition has a melt mass flow rate (MFR) of 0.1 to 10 g / 10 min and a density of 930 to 970 kg / m ３ The multilayer molded container according to claim 1 or 2, wherein the pigment 1 comprises aluminum oxide, silicon dioxide, and titanium oxide treated with siloxane.

4. A multilayer molded container according to any one of claims 1 to 3, wherein the recycled resin contains polyethylene and polypropylene, and the mass (g) of polyethylene:mass (g) of polypropylene in the recycled resin is 70-95:5-30.

5. The multilayer molded container according to any one of claims 1 to 4, wherein the pigment 1 comprises at least one pigment selected from the group consisting of Pigment Yellow 181 and Pigment Red 254.

6. A multilayer molded container according to any one of claims 1 to 5, wherein the pigment 1 comprises at least one selected from the group consisting of monoazo yellow, disazo yellow, monoazo orange, quinacridone red, diketopyrrolopyrrole red, phthalocyanine green, phthalocyanine blue, and quinacridone violet.

7. The multilayer molded container according to any one of claims 1 to 6, wherein the recycled resin comprises at least one selected from the group consisting of polyethylene and polypropylene.

8. The multilayer molded container according to any one of claims 1 to 7, wherein the inner layer further contains resin 1, and the resin 1 and the resin 2 contain polyolefins.

9. The multilayer molded container according to any one of claims 1 to 8, wherein the white pigment 2 contains titanium oxide.

10. A multilayer molded container according to any one of claims 1 to 9, wherein the content of the white pigment 2 is 2 to 20 mass % based on the outer layer.

11. The multilayer molded container according to any one of claims 1 to 10, wherein the pigment 1 includes a white pigment 1.

12. The multilayer molded container according to claim 11, wherein the white pigment 1 contains titanium oxide.

13. The multilayer molded container according to claim 11 or 12, wherein the content of the white pigment 1 is 1 to 25 mass % based on the inner layer.

14. The multilayer molded container according to any one of claims 1 to 13, which at least partially has a multilayer structure comprising the inner layer and the outer layer, the inner layer having a thickness of 300 to 2,500 μm, and the outer layer having a thickness of 50 to 1,000 μm.

15. The multilayer molded container according to any one of claims 1 to 14, wherein the lightness (L* value) of at least a portion of the surface is 80.0 to 99.

0.

16. A bottle, which is a multilayer molded container according to any one of claims 1 to 15.

17. A tube, which is a multilayer molded container according to any one of claims 1 to 15.

18. A recycled resin composition containing recycled resin obtained from PET bottle caps and pigment 1, which is used to manufacture the multilayer molded container described in any one of claims 1 to 15.

19. A method for manufacturing a multilayer molded container, comprising molding an inner layer material containing recycled resin obtained from PET bottle caps and pigment 1, and an outer layer material containing white pigment 2 and resin 2, using a blow molding method or an extrusion molding method.

20. A method for producing a multilayer molded container having an inner layer containing recycled resin obtained from PET bottle caps and pigment 1, and an outer layer containing white pigment 2 and resin 2, comprising molding an inner layer material containing the recycled resin composition described in claim 18 and an outer layer material containing white pigment 2 and resin 2 by a blow molding method or an extrusion molding method.

21. The method for producing a multilayer molded container according to claim 19 or 20, wherein the inner layer material further contains resin 1.

22. A method for producing a multilayer molded container according to any one of claims 19 to 21, comprising molding an inner layer and an outer layer that satisfy the following criteria: When a laminate consisting of the inner layer and the outer layer is formed, the brightness (L* value) measured from the outer layer side is 80.0 to 99.

0.

23. The method for producing a multilayer molded container according to any one of claims 19 to 22, wherein an inner layer that satisfies the following criteria is molded: The lightness (L* value) of the inner layer is 45.0 to 90.

0.

24. A method for producing a multilayer molded container according to any one of claims 19 to 23, wherein an outer layer that satisfies the following requirements is molded: The outer layer has a total light transmittance of 90.0% or less.

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