Extrusion molded article for pipe container and pipe container

Abstract

An extrusion molded article for a pipe container having a tubular shape as a whole, the extrusion molded article having a 5-layer structure in which an innermost layer, a first adhesive layer, an intermediate layer, a second adhesive layer, and an outermost layer are sequentially laminated, each of the innermost layer and the outermost layer containing a plant-derived polyethylene resin.

Description

TECHNICAL FIELD

[0001] The present application relates to an extrusion molded article for a tube container and a tube container. BACKGROUND

[0002] As a tube container that contains toothpaste, cosmetics, or the like, a laminated tube is known. The laminated tube is manufactured using a laminate sheet in which a polyethylene resin, a special paper, an aluminum foil, or the like is overlapped by a lamination process as a raw material. Generally, the laminated tube is manufactured by winding the laminate sheet into a cylindrical shape, overlapping both end portions of the sheet, welding the overlapped portions, and joining a lid fitting portion to the obtained container body.

[0003] The laminated tube has, for example, the following problems. The laminated tube is manufactured by overlapping both end portions, and thus a step difference is generated at the overlapped portions, and there is a problem in appearance. At the overlapped portions, the laminate sheet end face is exposed, and thus the contained content penetrates from the end face to the laminate interior, and the laminate sheet physical properties are reduced. Further, the laminated tube includes a process of winding into a cylindrical shape, and it is difficult to make the step difference unnoticeable, and thus it is difficult to make the wall thick, and it is difficult to maintain sufficient strength with a large diameter tube.

[0004] In order to eliminate the problems of the laminated tube, a container body of a tube container manufactured by extrusion molding has been proposed (Patent Documents 1 and 2). The tube container manufactured by extrusion molding is called an extrusion molded tube. The extrusion molded tube is manufactured by continuously extruding a molten resin into a tube shape using an extruder, and then cutting into an appropriate length, and joining a lid fitting portion to the obtained container body. In the case of a multilayer extrusion molded tube, a plurality of types of molten resins are extruded into one mold using different extruders, and a tube shape of a multilayer structure is formed in the mold to manufacture.

[0005] The mainstream of the tube containers currently in circulation is formed using a resin derived from petroleum.

[0006] PRIOR ART DOCUMENTS

[0007] PATENT DOCUMENTS

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 11-309406

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 11-309785 SUMMARY

[0010] PROBLEMS TO BE SOLVED BY THE INVENTION

[0011] The present inventors and others have been working on developing an extrusion molded tube with a polyethylene resin derived from plants in view of the problems of the laminated tube and environmental protection, and as a result, the following problems have been newly found.

[0012] When a plant-derived polyethylene resin is used in place of a petroleum-derived polyethylene resin, stress cracks are easily generated in an extrusion-molded pipe. In addition, when a multilayer extrusion-molded pipe composed of a resin layer containing a plant-derived polyethylene resin and a resin layer having gas barrier properties is manufactured, a tendency for a decrease in sealing strength is found. In addition, when a plant-derived polyethylene resin is used in place of a petroleum-derived polyethylene resin, the surface of the extrusion-molded pipe is not smooth, and surface roughness is easily caused.

[0013] Therefore, an object of the present application is to provide a technology of an extrusion-molded pipe containing a plant-derived polyethylene resin and excellent in stress cracking resistance, sealing strength, and surface smoothness.

[0014] Technical means for solving the technical problem

[0015] According to one aspect of the present application, there is provided an extrusion-molded article for a pipe container, which has a pipe shape as a whole, the extrusion-molded article having a 5-layer structure in which an innermost layer, a first adhesive layer, an intermediate layer, a second adhesive layer, and an outermost layer are sequentially laminated, the innermost layer and the outermost layer each containing a plant-derived polyethylene resin.

[0016] According to another aspect of the present application, there is provided a pipe container including: a container main body containing the extrusion-molded article whose one end is sealed; and a cap fitting portion engaged with the other end of the extrusion-molded article whose one end is sealed.

[0017] Effects of the Invention

[0018] According to the present application, it is possible to provide a technology of an extrusion-molded pipe containing a plant-derived polyethylene resin and excellent in stress cracking resistance, sealing strength, and surface smoothness. BRIEF DESCRIPTION OF DRAWINGS

[0019] [ Figure 1 ] is a cross-sectional view showing a 5-layer structure of an extrusion-molded article of one embodiment of the present application.

[0020] [ Figure 2 ] is a plan view showing a structure of a pipe container of one embodiment of the present application. DETAILED DESCRIPTION

[0021] Hereinafter, the present application will be described, but the purpose of the following description is to explain the present application in detail, and the present application is not intended to be limited thereto.

[0022] 1. Extrusion-molded article for a pipe container

[0023] The extrusion molded article for a tube container has a tube shape as a whole, and has a five-layer structure in which an innermost layer, a first adhesive layer, an intermediate layer, a second adhesive layer, and an outermost layer are sequentially laminated. The innermost layer and the outermost layer each contain a plant-derived polyethylene resin. In the following description, the extrusion molded article for a tube container is simply referred to as "extrusion molded article".

[0024] In the present specification, the proportion (%) of the plant-derived polyethylene resin contained in the extrusion molded article is referred to as "biomass degree". That is, the biomass degree refers to a value calculated by the following formula.

[0025] Biomass degree (%) = {(total mass of plant-derived polyethylene resins) / (total mass of all resins constituting the extrusion molded article)} x 100

[0026] 1-1. Structure

[0027] The extrusion molded article has a tube shape as a whole, and has a five-layer structure in which an innermost layer, a first adhesive layer, an intermediate layer, a second adhesive layer, and an outermost layer are sequentially laminated. Figure 1 is a cross-sectional view showing the five-layer structure of the extrusion molded article according to one embodiment of the present application. As shown in Figure 1 The extrusion molded article 1 has a five-layer structure in which an innermost layer la, a first adhesive layer lb, an intermediate layer lc, a second adhesive layer Id, and an outermost layer le are sequentially laminated. Figure 1 When the extrusion molded article 1 shown in FIG. 1 is used as a container body of a tube container, the surface on the innermost layer la side is adjacent to the inner space of the tube container, and the surface on the outermost layer le side is adjacent to the outer space of the tube container.

[0028] The extrusion molded article 1 can have a cylindrical shape or an elliptical cylindrical shape. The extrusion molded article 1 has, for example, a circumference of 30 to 190 mm. The extrusion molded article 1 preferably has a circumference of 40 to 160 mm. The circumference refers to the length of the outer periphery of the tubular extrusion molded article 1.

[0029] The extrusion molded article 1 has, for example, a thickness of 0.19 to 0.55 mm, and preferably has a thickness of 0.24 to 0.5 mm. The thickness refers to the thickness of the wall of the tubular extrusion molded article 1, and is the average value of the thicknesses measured at three positions set at substantially equal intervals in the length direction of the extrusion molded article 1.

[0030] The innermost layer la has a thickness of, for example, 0.12 to 0.25 mm, preferably 0.14 to 0.24 mm. The first adhesive layer lb has a thickness of, for example, 0.001 to 0.03 mm, preferably 0.005 to 0.02 mm. The intermediate layer lc has a thickness of, for example, 0.01 to 0.1 mm, preferably 0.02 to 0.08 mm. The second adhesive layer Id has a thickness of, for example, 0.001 to 0.03 mm, preferably 0.005 to 0.02 mm. The outermost layer le has a thickness of, for example, 0.06 to 0.2 mm, preferably 0.08 to 0.18 mm.

[0031] The extrusion molded article 1 can have an arbitrary length, and can have a length longer than the container body of the tube container, or can have the same length as the container body of the tube container. In the former case, the extrusion molded article 1 is cut to the length of the container body of the tube container, and used as the container body of the tube container.

[0032] 1-2. Resin

[0033] Hereinafter, the resins constituting the innermost layer la, the first adhesive layer lb, the intermediate layer lc, the second adhesive layer Id, and the outermost layer le will be described in order.

[0034] (Innermost layer la)

[0035] The innermost layer la contains a polyethylene resin derived from a plant. In the preferred embodiment, the innermost layer la contains a low density polyethylene resin (Low Density Polyethylene: LDPE) and a linear low density polyethylene resin (Linear Low Density Polyethylene: L-LDPE), at least one of the low density polyethylene resin (LDPE) and the linear low density polyethylene resin (L-LDPE) being derived from a plant.

[0036] That is, in the preferred embodiment, with respect to the innermost layer la,

[0037] a low density polyethylene resin derived from a plant (biomass LDPE) and a linear low density polyethylene resin derived from a plant (biomass L-LDPE) can be contained,

[0038] a low density polyethylene resin derived from a plant (biomass LDPE) and a linear low density polyethylene resin derived from petroleum (petroleum L-LDPE) can be contained,

[0039] a low density polyethylene resin derived from petroleum (petroleum LDPE) and a linear low density polyethylene resin derived from a plant (biomass L-LDPE) can be contained.

[0040] Low-density polyethylene resin (LDPE) and linear low-density polyethylene resin (L-LDPE) differ in structure depending on the manufacturing method. That is, low-density polyethylene resin (LDPE) is a polymer of ethylene, having a structure in which ethylene is randomly branched and bonded. Thus, low-density polyethylene resin (LDPE) has side chains of various carbon atom numbers bonded to the main chain, the side chains including short-chain branches (e.g., short-chain branches of about 20 or less carbon atoms) and long-chain branches (e.g., long-chain branches of more than about 20 carbon atoms). On the other hand, linear low-density polyethylene resin (L-LDPE) is a copolymer of ethylene and a-olefin. Thus, linear low-density polyethylene resin (L-LDPE) has no long-chain branches (e.g., long-chain branches of more than about 20 carbon atoms) bonded to the main chain, but only has short-chain branches (e.g., short-chain branches of about 20 or less carbon atoms) bonded to the main chain.

[0041] In a more preferable embodiment, the innermost layer la contains a low-density polyethylene resin derived from plants (biomass LDPE) and a linear low-density polyethylene resin derived from plants (biomass L-LDPE). This embodiment is referred to as "first embodiment" in the following description.

[0042] In another more preferable embodiment, the innermost layer la contains a low-density polyethylene resin derived from plants (biomass LDPE) and a linear low-density polyethylene resin derived from petroleum (petroleum L-LDPE). This embodiment is referred to as "second embodiment" in the following description.

[0043] In another more preferable embodiment, the innermost layer la contains a low-density polyethylene resin derived from petroleum (petroleum LDPE) and a linear low-density polyethylene resin derived from plants (biomass L-LDPE). This embodiment is referred to as "third embodiment" in the following description.

[0044] The innermost layer la can contain low-density polyethylene resin (LDPE) and linear low-density polyethylene resin (L-LDPE) in a mass ratio of, for example, 9:1 to 1:9.

[0045] In the first embodiment, the innermost layer la contains a low-density polyethylene resin derived from plants (biomass LDPE) and a linear low-density polyethylene resin derived from plants (biomass L-LDPE) in a mass ratio of, for example, 9:1 to 4:6, preferably in a mass ratio of 8:2 to 4:6, more preferably in a mass ratio of 7:3 to 4:6, further preferably in a mass ratio of 6:4 to 4:6.

[0046] In the second embodiment, the innermost layer la contains a low-density polyethylene resin derived from plants (biomass LDPE) and a linear low-density polyethylene resin derived from petroleum (petroleum L-LDPE), for example, at a mass ratio of 9:1 to 4:6, preferably at a mass ratio of 9:1 to 5:5, more preferably at a mass ratio of 9:1 to 6:4, further preferably at a mass ratio of 9:1 to 7:3.

[0047] In the third embodiment, the innermost layer la contains a low-density polyethylene resin derived from petroleum (petroleum LDPE) and a linear low-density polyethylene resin derived from plants (biomass L-LDPE), for example, at a mass ratio of 6:4 to 1:9, preferably at a mass ratio of 5:5 to 1:9, more preferably at a mass ratio of 4:6 to 1:9, further preferably at a mass ratio of 4:6 to 2:8.

[0048] Hereinafter, a "low-density polyethylene resin derived from plants (biomass LDPE)", a "linear low-density polyethylene resin derived from plants (biomass L-LDPE)", a "low-density polyethylene resin derived from petroleum (petroleum LDPE)", and a "linear low-density polyethylene resin derived from petroleum (petroleum L-LDPE)" will be described in detail.

[0049] "Low-density polyethylene resin derived from plants (biomass LDPE)"

[0050] The "low-density polyethylene resin derived from plants (biomass LDPE)" is a polymer of ethylene manufactured using plants as a raw material, and has a structure in which ethylene is branched and bonded at random. The "low-density polyethylene resin derived from plants (biomass LDPE)" is, for example, a low-density polyethylene resin derived from sugar cane. The low-density polyethylene resin derived from sugar cane is a polymer of ethylene manufactured using sugar cane as a raw material, and has a structure in which ethylene is branched and bonded at random.

[0051] The density of the "low-density polyethylene resin derived from plants (biomass LDPE)" is preferably in the range of 0.91 g / cm 3 to 0.93 g / cm 3 , more preferably in the range of 0.915 g / cm 3 to 0.93 g / cm 3 . Note that the density of the resin described in this specification is a measured value obtained according to the method of JIS K7112:1999.

[0052] Further, the melt flow rate (MFR) of the "plant-derived low-density polyethylene resin (biomass LDPE)" is preferably in the range of 0.1 g / 10 minutes to 10 g / 10 minutes, more preferably in the range of 1 g / 10 minutes to 5 g / 10 minutes. Note that the melt flow rate (MFR) of the resin described in this specification is a measured value obtained according to the method of JIS K7210:1999. Specifically, the melt flow rate is a measured value of the weight of the resin discharged in 10 minutes when a load of 21.18 N is applied to the resin at 190°C.

[0053] The "plant-derived low-density polyethylene resin (biomass LDPE)" can be, for example, a plant-derived low-density polyethylene sold by Braskem Co., and as examples thereof, resins sold under the trade names of SEB853, SBC818, SBF0323HC, STN7006, and SPB618 can be mentioned.

[0054] "Plant-derived linear low-density polyethylene resin (biomass L-LDPE)"

[0055] The "plant-derived linear low-density polyethylene resin (biomass L-LDPE)" is a copolymer of ethylene and an α-olefin produced using a plant as a raw material. The "plant-derived linear low-density polyethylene resin (biomass L-LDPE)" is, for example, a linear low-density polyethylene resin derived from sugar cane. The linear low-density polyethylene resin derived from sugar cane is a copolymer of ethylene and an α-olefin produced using sugar cane as a raw material.

[0056] The "α-olefin" is at least one compound selected from α-olefins having a carbon atom number of 3 to 20, and examples thereof include 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, and the like.

[0057] The density of the "plant-derived linear low-density polyethylene resin (biomass L-LDPE)" is preferably in the range of 0.91 g / cm 3 to 0.93 g / cm 3 , more preferably in the range of 0.915 g / cm 3 to 0.93 g / cm 3 . Further, the melt flow rate (MFR) of the "plant-derived linear low-density polyethylene resin (biomass L-LDPE)" is preferably in the range of 0.1 g / 10 minutes to 10 g / 10 minutes, more preferably in the range of 1 g / 10 minutes to 5 g / 10 minutes.

[0058] The "plant-derived linear low-density polyethylene resin (biomass L-LDPE)" can use, for example, a plant-derived linear low-density polyethylene sold by the Braskem Corporation, and as examples thereof, resins sold under the trade names of SLL118, SLL118 / 21, SLL218, SLL218 / 21, SLL318, SLH118, SLH218, and SLH0820 / 30AF can be mentioned.

[0059] The "petroleum-derived low-density polyethylene resin (petroleum LDPE)"

[0060] The "petroleum-derived low-density polyethylene resin (petroleum LDPE)" is a polymer of ethylene manufactured using petroleum as a raw material, and has a structure in which ethylene is randomly branched and bonded.

[0061] The density of the "petroleum-derived low-density polyethylene resin (petroleum LDPE)" is preferably in the range of 0.91 g / cm 3 ~ 0.93 g / cm 3 , more preferably in the range of 0.915 g / cm 3 ~ 0.93 g / cm 3 . Further, the melt flow rate (MFR) of the "petroleum-derived low-density polyethylene resin (petroleum LDPE)" is preferably in the range of 0.1 g / 10 minutes ~ 10 g / 10 minutes, more preferably in the range of 1 g / 10 minutes ~ 5 g / 10 minutes.

[0062] The "petroleum-derived low-density polyethylene resin (petroleum LDPE)" can use a commercially available petroleum-derived low-density polyethylene resin, and as examples thereof, resins sold under the trade names of MIRASON by DOW-MITSUI POLYCHEMICAL S Co., Ltd., NOVATEC by JAPAN POLYETHYLENE Co., Ltd., PETROSEN by TOAGOSEI Co., Ltd., and NUC by ENEOS NUC Co., Ltd. can be mentioned.

[0063] The "petroleum-derived linear low-density polyethylene resin (petroleum L-LDPE)"

[0064] The "petroleum-derived linear low-density polyethylene resin (petroleum L-LDPE)" is a copolymer of ethylene and an α-olefin manufactured using petroleum as a raw material.

[0065] The "α-olefin" is at least one compound selected from α-olefins having a carbon atom number of 3 ~ 20, and for example, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, and the like can be mentioned.

[0066] The density of the "petroleum-derived linear low-density polyethylene resin (petroleum L-LDPE)" is preferably in the range of 0.91 g / cm3 3 ~ 0.93 g / cm3, 3 more preferably in the range of 0.915 g / cm3 3 ~ 0.93 g / cm3. 3 Further, the melt flow rate (MFR) of the "petroleum-derived linear low-density polyethylene resin (petroleum L-LDPE)" is preferably in the range of 0.1 g / 10 minutes ~ 10 g / 10 minutes, more preferably in the range of 1 g / 10 minutes ~ 5 g / 10 minutes.

[0067] The "petroleum-derived linear low-density polyethylene resin (petroleum L-LDPE)" can use a commercially available petroleum-derived linear low-density polyethylene resin, as examples of which, resins sold by PRIME POLYMER Co., Ltd. under the trade names of EVOLUE, NEO-ZEX, or ULT-ZEX, resins sold by JAPAN POLYETHYLENE Co., Ltd. under the trade name of NOVATEC can be cited.

[0068] (First adhesive layer 1b)

[0069] The first adhesive layer 1b functions to adhere the innermost layer 1a to the intermediate layer 1c. The first adhesive layer 1b contains, for example, an acid-modified polyethylene resin. The "acid-modified polyethylene resin" is preferably a maleic anhydride-modified polyethylene resin.

[0070] The first adhesive layer 1b typically contains a petroleum-derived acid-modified polyethylene resin. The "petroleum-derived acid-modified polyethylene resin" is a resin obtained by modifying a polyethylene derived from petroleum with an unsaturated carboxylic acid or an acid anhydride thereof. The resin is imparted with adhesiveness by acid modification, and is therefore well known as an adhesive resin. As specific examples of the unsaturated carboxylic acid or the acid anhydride thereof, acrylic acid, methacrylic acid, a-ethylacrylic acid, maleic acid, fumaric acid, itaconic acid, citric acid, tetrahydrophthalic acid, chloromaleic acid, butenylsuccinic acid, and acid anhydrides thereof can be cited.

[0071] The "petroleum-derived acid-modified polyethylene resin" is preferably a petroleum-derived maleic anhydride-modified polyethylene resin. More preferably, the "petroleum-derived acid-modified polyethylene resin" is a petroleum-derived maleic anhydride-modified low-density polyethylene resin (MA-modified LDPE), a petroleum-derived maleic anhydride-modified linear low-density polyethylene resin (MA-modified L-LDPE), or a mixture thereof.

[0072] The "petroleum-derived maleic anhydride-modified low-density polyethylene resin (MA-modified LDPE)" is a resin obtained by modifying a homopolymer of ethylene produced using petroleum as a raw material with maleic anhydride.

[0073] The density of the "petroleum-derived maleic anhydride-modified low-density polyethylene resin (MA-modified LDPE)" is preferably in the range of 0.91 g / cm 3 ~ 0.93 g / cm 3 , more preferably in the range of 0.915 g / cm 3 ~ 0.93 g / cm 3 . As described above, the density of the resin described in the present specification is a measured value obtained in accordance with the method of JIS K7112:1999.

[0074] Further, the melt flow rate (MFR) of the "petroleum-derived maleic anhydride-modified low-density polyethylene resin (MA-modified LDPE)" is preferably in the range of 0.1 g / 10 minutes ~ 10 g / 10 minutes, more preferably in the range of 1 g / 10 minutes ~ 5 g / 10 minutes. As described above, the melt flow rate (MFR) of the resin described in the present specification is a measured value obtained in accordance with the method of JIS K7210:1999. Specifically, the melt flow rate is a measured value of the weight of the resin discharged in 10 minutes when a load of 21.18 N is applied to the resin at 190°C.

[0075] The "petroleum-derived maleic anhydride-modified low-density polyethylene resin (MA-modified LDPE)" can be used, for example, a resin sold by Mitsubishi Chemical Corporation under the trade name of "MODIC" (registered trademark), a resin sold by Mitsui Chemicals, Inc. under the trade name of "ADMER" (registered trademark), or the like.

[0076] The "petroleum-derived maleic anhydride-modified linear low-density polyethylene resin (MA-modified L-LDPE)" is a resin obtained by modifying an ethylene copolymer using petroleum as a raw material with maleic anhydride. The "α-olefin" is at least one compound selected from α-olefins having a carbon atom number of 3 ~ 20, and examples thereof include 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, and the like.

[0077] The density of the "petroleum-derived maleic anhydride-modified linear low-density polyethylene resin (MA-modified L-LDPE)" is preferably in the range of 0.91 g / cm 3 ~ 0.93 g / cm 3 , more preferably in the range of 0.915 g / cm 3 ~ 0.93 g / cm 3Furthermore, the melt flow rate (MFR) of the "petroleum-derived maleic anhydride-modified linear low-density polyethylene resin (MA-modified L-LDPE)" is preferably in the range of 0.1 g / 10 minutes to 10 g / 10 minutes, more preferably in the range of 1 g / 10 minutes to 5 g / 10 minutes.

[0078] The "petroleum-derived maleic anhydride-modified linear low-density polyethylene resin (MA-modified L-LDPE)" can be, for example, a resin sold under the trade name of "ADMER" (registered trademark) by Mitsui Chemicals, Inc., a resin sold under the trade name of "MODIC" (registered trademark) by Mitsubishi Chemical Corporation, a resin sold under the trade name of "OREVAC" (registered trademark) by ARKEMA, or the like.

[0079] (Intermediate layer 1c)

[0080] The intermediate layer 1c preferably contains a resin having gas barrier properties. The resin constituting the intermediate layer 1c can use a resin known as a resin having gas barrier properties. The resin constituting the intermediate layer 1c is, for example, an ethylene-vinyl alcohol copolymer resin (EVOH), a nylon (NY), a polyvinyl alcohol (PVA), a polyacrylonitrile (PAN), a polyvinylidene chloride (PVDC), and is preferably an ethylene-vinyl alcohol copolymer resin (EVOH).

[0081] The ethylene-vinyl alcohol copolymer resin (EVOH) can be, for example, a resin sold under the trade name of "SOARNOL" (registered trademark) by Mitsubishi Chemical Corporation, a resin sold under the trade name of "EVAL" (registered trademark) by Kuraray Co., Ltd., or the like.

[0082] (Second adhesive layer 1d)

[0083] The second adhesive layer 1d functions to adhere the outermost layer 1e to the intermediate layer 1c. The second adhesive layer 1d contains, for example, an acid-modified polyethylene resin. The "acid-modified polyethylene resin" is preferably a maleic anhydride-modified polyethylene resin.

[0084] The second adhesive layer 1d typically contains a petroleum-derived acid-modified polyethylene resin. The "petroleum-derived acid-modified polyethylene resin" is preferably a petroleum-derived maleic anhydride-modified polyethylene resin. More preferably, the "petroleum-derived acid-modified polyethylene resin" is a petroleum-derived maleic anhydride-modified low-density polyethylene resin (MA-modified LDPE), a petroleum-derived maleic anhydride-modified linear low-density polyethylene resin (MA-modified L-LDPE), or a mixture thereof.

[0085] The "petroleum-derived acid-modified polyethylene resin" contained in the second adhesive layer 1d can be the same as the "petroleum-derived acid-modified polyethylene resin" described above with respect to the first adhesive layer 1b. The second adhesive layer 1d can have the same resin composition as the first adhesive layer 1b, or can have a different resin composition from the first adhesive layer 1b.

[0086] (outermost layer 1e)

[0087] The outermost layer 1e contains a plant-derived polyethylene resin. In a preferred embodiment, the outermost layer 1e contains a low-density polyethylene resin (LDPE) and a linear low-density polyethylene resin (L-LDPE), at least one of which is derived from a plant.

[0088] That is, in a preferred embodiment, with respect to the outermost layer 1e,

[0089] a plant-derived low-density polyethylene resin (biomass LDPE) and a plant-derived linear low-density polyethylene resin (biomass L-LDPE) can be contained,

[0090] a plant-derived low-density polyethylene resin (biomass LDPE) and a petroleum-derived linear low-density polyethylene resin (petroleum L-LDPE) can be contained,

[0091] a petroleum-derived low-density polyethylene resin (petroleum LDPE) and a plant-derived linear low-density polyethylene resin (biomass L-LDPE) can be contained.

[0092] In a more preferred embodiment, the outermost layer 1e contains a plant-derived low-density polyethylene resin (biomass LDPE) and a plant-derived linear low-density polyethylene resin (biomass L-LDPE). This embodiment is referred to as the "first embodiment" in the following description.

[0093] In another more preferred embodiment, the outermost layer 1e contains a plant-derived low-density polyethylene resin (biomass LDPE) and a petroleum-derived linear low-density polyethylene resin (petroleum L-LDPE). This embodiment is referred to as the "second embodiment" in the following description.

[0094] In another more preferred embodiment, the outermost layer 1e contains a petroleum-derived low-density polyethylene resin (petroleum LDPE) and a plant-derived linear low-density polyethylene resin (biomass L-LDPE). This embodiment is referred to as the "third embodiment" in the following description.

[0095] The outermost layer 1e can contain a low-density polyethylene resin (LDPE) and a linear low-density polyethylene resin (L-LDPE) in a mass ratio of, for example, 9:1 to 1:9.

[0096] In the first embodiment, the outermost layer 1e contains a plant-derived low-density polyethylene resin (biomass LDPE) and a plant-derived linear low-density polyethylene resin (biomass L-LDPE) in a mass ratio of, for example, 9:1 to 4:6, preferably in a mass ratio of 8:2 to 4:6, more preferably in a mass ratio of 7:3 to 4:6, further preferably in a mass ratio of 6:4 to 4:6.

[0097] In the second embodiment, the outermost layer 1e contains a plant-derived low-density polyethylene resin (biomass LDPE) and a petroleum-derived linear low-density polyethylene resin (petroleum L-LDPE) in a mass ratio of, for example, 9:1 to 4:6, preferably in a mass ratio of 9:1 to 5:5, more preferably in a mass ratio of 9:1 to 6:4, further preferably in a mass ratio of 9:1 to 7:3.

[0098] In the third embodiment, the outermost layer 1e contains a petroleum-derived low-density polyethylene resin (petroleum LDPE) and a plant-derived linear low-density polyethylene resin (biomass L-LDPE) in a mass ratio of, for example, 6:4 to 1:9, preferably in a mass ratio of 5:5 to 1:9, more preferably in a mass ratio of 4:6 to 1:9, further preferably in a mass ratio of 4:6 to 2:8.

[0099] The resins contained in the outermost layer 1e, i.e., the "plant-derived low-density polyethylene resin (biomass LDPE)", the "plant-derived linear low-density polyethylene resin (biomass L-LDPE)", the "petroleum-derived low-density polyethylene resin (petroleum LDPE)", and the "petroleum-derived linear low-density polyethylene resin (petroleum L-LDPE)", are the same as those described in the innermost layer 1a, and their descriptions can be referred to. The outermost layer 1e can have the same resin composition as the innermost layer 1a or a different resin composition from the innermost layer 1a.

[0100] (Additives)

[0101] The innermost layer 1a, the first adhesive layer 1b, the intermediate layer 1c, the second adhesive layer 1d, and the outermost layer 1e are composed of a resin as a main component, and in addition to the resin, a publicly known additive can be included as necessary. As the additive, various additives known as additives for resins can be used. As the additive, for example, an antioxidant, an ultraviolet absorber, a weathering agent, an antistatic agent, a filler, a crystallization nucleating agent, a coloring pigment, a matting agent, a coloration preventive agent, an antifogging agent, a flame retardant, an antiblocking agent, a lubricant (including a slip agent, a release agent), and a CO2absorbing agent, etc. can be cited. The total content of the additive can be, for example, 0.01 to 10 parts by mass with respect to 100 parts by mass of the resin of each layer.

[0102] (biomass degree)

[0103] The extrusion molded article 1 having 5 layers contains a plant-derived polyethylene resin in an amount of, for example, more than 40 mass%. The extrusion molded article 1 contains a plant-derived polyethylene resin in an amount of preferably more than 50 mass%, more preferably more than 60 mass%, and further preferably more than 70 mass%. That is, the proportion of the plant-derived polyethylene resin contained in the extrusion molded article 1 (i.e., the biomass degree) is, for example, more than 40 mass%, preferably more than 50 mass%, more preferably more than 60 mass%, and further preferably more than 70 mass%.

[0104] The upper limit of the proportion of the plant-derived polyethylene resin contained in the extrusion molded article 1 (i.e., the biomass degree) is, for example, 85 mass%.

[0105] 1-3. Production method

[0106] The extrusion molded article 1 can be produced according to a publicly known co-extrusion molding method. That is, the resin constituting the innermost layer 1a, the resin constituting the first adhesive layer 1b, the resin constituting the intermediate layer 1c, the resin constituting the second adhesive layer 1d, and the resin constituting the outermost layer 1e can be extruded into one mold using respective extruders to form a tube shape having a 5-layer structure in the mold.

[0107] In the present specification, the term "extrusion molded article" refers to a product formed by extrusion molding so as to have a tube shape. In other words, the term "extrusion molded article" refers to a product having a tube shape immediately after extrusion molding. Therefore, the term "extrusion molded article" does not include a product in which an extrusion molded article in a sheet shape is wound into a tube shape.

[0108] 2. Molded article for a tube container

[0109] The extrusion molded article 1 can have one or more additional layers on the extrusion molded article 1. That is, according to another aspect, there is provided a molded article for a tube container, which has an extrusion molded article and one or more layers provided on the extrusion molded article. The molded article for a tube container is simply referred to as "molded article" in the following description.

[0110] The additional layer can be formed on the extrusion molded article by a known decoration technique, such as printing, coating (e.g., transparent coating for surface protection of a printed layer), label sticking, hot stamping, shrink film sticking, vapor deposition, or film transfer. The additional layer can be one layer or a plurality of layers, such as one to five layers.

[0111] 3. Tube container

[0112] The tube container has

[0113] a container body including the extrusion molded article sealed at one end; and

[0114] a cap fitting portion engaged with the other end of the extrusion molded article sealed at the one end.

[0115] Alternatively, the tube container preferably has:

[0116] a container body including the molded article sealed at one end; and

[0117] a cap fitting portion engaged with the other end of the molded article sealed at the one end.

[0118] Hereinafter, the following Figure 2 A tube container according to one embodiment of the present application is described. Figure 2 is a plan view showing the structure of the tube container according to one embodiment of the present application.

[0119] As shown in Figure 2 The tube container 10 has a container body 11 and a cap fitting portion 12 engaged with the container body 11. The tube container 10 is used by filling the container body 11 with a content and fitting a cap to the cap fitting portion 12. Here, the content can be a high-viscosity liquid or a semi-solid. The content is, for example, a daily necessity such as a facial wash, a cosmetic, a toothpaste, a hand cream, a jam, or butter.

[0120] The container body 11 is obtained by sealing one end of the extrusion molded article 1 described above. The sealing can be performed by a method known as an end sealing process of a tube container, for example, by a heat sealing method, an ultrasonic sealing method, a hot air sealing method. As described above, in the extrusion molded article 1, one or more additional layers can be provided on the outer surface before the one end is sealed. That is, the container body 11 can further include one or more additional layers formed by, for example, printing, coating (e.g., transparent coating for surface protection of a printed layer), label sticking, hot stamping, shrink film sticking, vapor deposition, or film transfer, in accordance with a known decoration technique.

[0121] As shown in FIG. 1, the container body 11 has a body portion 21 and a sealing portion 22 provided at one end of the body portion 21. Figure 2

[0122] The body portion 21 is an unsealed portion of the extrusion molded article 1 or the molded article. The end of the body portion 21, at which the sealing portion 22 is not provided, has a cylindrical shape having a circular or elliptical shape when viewed from the opening portion.

[0123] The sealing portion 22 is a portion formed by fusion of one end of the extrusion molded article 1 or the molded article using heat. The sealing portion 22 has a flat shape, and the opposite inner surfaces thereof are sealed to each other. The sealing portion 22 closes one end of the container body 11.

[0124] The cap fitting portion 12 is provided at the end of the body portion 21 opposite to the end at which the sealing portion 22 is provided. The cap fitting portion 12 has a shoulder portion 31 continuously with the end of the body portion 21 at which the sealing portion 22 is not provided, and a cylindrical mouth portion 32 provided at the center of the shoulder portion 31. The cap fitting portion 12 is manufactured separately from the body portion 21 by injection molding or compression molding, and is joined to the body portion 21. In the case of injection molding, the formation of the cap fitting portion 12 and the joining of the cap fitting portion 12 to the container body 11 can be performed simultaneously by insert molding, or the cap fitting portion 12 can be injection molded as another component, and then joined to the container body 11 by ultrasonic fusion.

[0125] The outer surface of the shoulder portion 31 facing the outside space of the tube container 10 and the inner surface of the shoulder portion 31 facing the inside space of the tube container 10 each have a frustoconical shape gradually tapering from the inside space toward the outside space. The outer periphery of the shoulder portion 31 is continuous with the body portion 21. The mouth portion 32 is provided at the center of the shoulder portion 31 in a manner protruding outward.

[0126] 4. Effects

[0127] ​As described above, the extrusion molded article, the molded article, and the tube container of the present application have a 5-layer structure in which the innermost layer la, the first adhesive layer lb, the intermediate layer lc, the second adhesive layer Id, and the outermost layer le are sequentially laminated, and the innermost layer la and the outermost layer le each contain a plant-derived polyethylene resin. In the present application, by providing the adhesive layers as independent layers and forming the extrusion molded tube in which the plant-derived polyethylene resin is incorporated into a 5-layer structure, excellent stress cracking resistance, excellent sealing strength, and excellent surface smoothness can be achieved.

[0128] It is preferable that the extrusion molded article, the molded article, and the tube container of the present application contain, in addition to the above 5-layer structure, a low-density polyethylene resin (LDPE) and a linear low-density polyethylene resin (L-LDPE) in the innermost layer la and the outermost layer le, respectively, at least one of which is derived from a plant. In the present application, by using such a specific combination of resins, more excellent stress cracking resistance, more excellent sealing strength, and more excellent surface smoothness can be achieved.

[0129] Further, the extrusion molded article, the molded article, and the tube container of the present application have the following advantages. The extrusion molded article, the molded article, and the tube container of the present application contain a plant-derived polyethylene resin, and thus, compared to the case of a petroleum-derived polyethylene resin, can contribute to the reduction of CO2 emissions. Further, the extrusion molded article, the molded article, and the tube container of the present application are manufactured by extrusion molding, and thus, in a laminated tube, there is no visible overlapping portion (i.e., a seam), and a seamless appearance can be achieved. Further, the extrusion molded article, the molded article, and the tube container of the present application are manufactured by extrusion molding, and thus, compared to a laminated tube, it is easy to thicken the wall, and even a tube container with a large diameter can maintain sufficient strength.

[0130] Further, the extrusion molded article, the molded article, and the tube container of the present application have the above 5-layer structure, and thus, have the following advantages. In a multi-layer structure tube, in the case where the innermost layer and the outermost layer are adhered to the intermediate layer having gas barrier properties, two methods are considered, a method in which an adhesive resin is incorporated into the innermost layer and the outermost layer, and a method in which adhesive layers containing an adhesive resin are provided between the innermost layer and the intermediate layer and between the outermost layer and the intermediate layer. In the present application, the former method is adopted, and the first adhesive layer lb and the second adhesive layer Id are provided as independent layers to form a 5-layer structure, and thus, it is not necessary to incorporate an adhesive resin into the innermost layer la and the outermost layer le. Therefore, in the present application, the proportion of the plant-derived polyethylene resin contained in the innermost layer la and the outermost layer le can be increased to a maximum of 100 mass%, and thus, the degree of biomass of the extrusion molded article can be increased.

[0131] Further, in the present application, since the first adhesive layer 1b and the second adhesive layer 1d are provided as independent layers to form a 5-layer structure, the adhesive resin is not diluted as in the case where the adhesive resin is incorporated in the innermost layer 1a and the outermost layer 1e. Therefore, in the present application, the amount of use of the adhesive resin can be reduced. The adhesive resin has a special chemical structure in order to exhibit adhesiveness, and is a relatively expensive material, so that if the amount of use of the adhesive resin is reduced, the cost can be reduced.

[0132] 5. Preferred mode

[0133] Hereinafter, a preferred mode is described.

[0134] [1] An extrusion molded article for a pipe container, which has a tubular shape as a whole, the extrusion molded article having a 5-layer structure in which an innermost layer, a first adhesive layer, an intermediate layer, a second adhesive layer, and an outermost layer are sequentially stacked, each of the innermost layer and the outermost layer containing a polyethylene resin derived from a plant.

[0135] [2] The extrusion molded article according to [1], wherein each of the innermost layer and the outermost layer contains a low-density polyethylene resin and a linear low-density polyethylene resin, at least one of the low-density polyethylene resin and the linear low-density polyethylene resin being derived from a plant.

[0136] [3] The extrusion molded article according to [2], wherein each of the innermost layer and the outermost layer contains a low-density polyethylene resin derived from a plant and a linear low-density polyethylene resin derived from a plant.

[0137] [4] The extrusion molded article according to [2], wherein each of the innermost layer and the outermost layer contains a low-density polyethylene resin derived from a plant and a linear low-density polyethylene resin derived from petroleum.

[0138] [5] The extrusion molded article according to [2], wherein each of the innermost layer and the outermost layer contains a low-density polyethylene resin derived from petroleum and a linear low-density polyethylene resin derived from a plant.

[0139] [6] The extrusion molded article according to any one of [2] to [5], wherein each of the innermost layer and the outermost layer contains the low-density polyethylene resin and the linear low-density polyethylene resin at a mass ratio of 9: 1 to 1: 9.

[0140] [7] The extrusion molded article according to [3], wherein each of the innermost layer and the outermost layer contains the plant-derived low-density polyethylene resin and the plant-derived linear low-density polyethylene resin in a mass ratio of 9: 1 to 4: 6, preferably in a mass ratio of 8: 2 to 4: 6, more preferably in a mass ratio of 7: 3 to 4: 6, further preferably in a mass ratio of 6: 4 to 4: 6.

[0141] [8] The extrusion molded article according to [4], wherein each of the innermost layer and the outermost layer contains the plant-derived low-density polyethylene resin and the petroleum-derived linear low-density polyethylene resin in a mass ratio of 9: 1 to 4: 6, preferably in a mass ratio of 9: 1 to 5: 5, more preferably in a mass ratio of 9: 1 to 6: 4, further preferably in a mass ratio of 9: 1 to 7: 3.

[0142] [9] The extrusion molded article according to [5], wherein each of the innermost layer and the outermost layer contains the petroleum-derived low-density polyethylene resin and the plant-derived linear low-density polyethylene resin in a mass ratio of 6: 4 to 1: 9, preferably in a mass ratio of 5: 5 to 1: 9, more preferably in a mass ratio of 4: 6 to 1: 9, further preferably in a mass ratio of 4: 6 to 2: 8.

[0143]

[10] The extrusion molded article according to [3] or [7], wherein the plant-derived low-density polyethylene resin has a density of 0.91 g / cm 3 to 0.93 g / cm 3 , preferably has a density of 0.915 g / cm 3 to 0.93 g / cm 3 .

[0144]

[11] The extrusion molded article according to [3], [7] or

[10] , wherein the plant-derived low-density polyethylene resin has a melt flow rate of 0.1 g / 10 minutes to 10 g / 10 minutes, preferably has a melt flow rate of 1 g / 10 minutes to 5 g / 10 minutes.

[0145]

[12] The extrusion molded article according to [3], [7],

[10] or

[11] , wherein the plant-derived linear low-density polyethylene resin has a density of 0.91 g / cm 3 to 0.93 g / cm 3 , preferably has a density of 0.915 g / cm 3 to 0.93 g / cm 3 .

[0146]

[13] The extrusion molded article according to [3], [7],

[10] ,

[11] or

[12] , wherein the plant-derived linear low-density polyethylene resin has a melt flow rate of 0.1 to 10 g / 10 minutes, preferably 1 to 5 g / 10 minutes.

[0147]

[14] The extrusion molded article according to [4] or [8], wherein the petroleum-derived low-density polyethylene resin has a density of 0.91 to 0.93 g / cm 3 3 3 3

[0148]

[15] The extrusion molded article according to [4], [8] or

[14] , wherein the petroleum-derived low-density polyethylene resin has a melt flow rate of 0.1 to 10 g / 10 minutes, preferably 1 to 5 g / 10 minutes.

[0149]

[16] The extrusion molded article according to [4], [8],

[14] or

[15] , wherein the petroleum-derived linear low-density polyethylene resin has a density of 0.91 to 0.93 g / cm 3 3 3 3

[0150]

[17] The extrusion molded article according to [4], [8],

[14] ,

[15] or

[16] , wherein the petroleum-derived linear low-density polyethylene resin has a melt flow rate of 0.1 to 10 g / 10 minutes, preferably 1 to 5 g / 10 minutes.

[0151]

[18] The extrusion molded article according to [5] or [9], wherein the petroleum-derived low-density polyethylene resin has a density of 0.91 to 0.93 g / cm 3 3 3 3

[0152] ​​​​​​​​​​​​

[19] The extrusion molded article according to [5], [9] or

[18] , wherein the petroleum-derived low-density polyethylene resin has a melt flow rate of 0.1 g / 10 min to 10 g / 10 min, preferably a melt flow rate of 1 g / 10 min to 5 g / 10 min.

[0153]

[20] The extrusion molded article according to [5], [9],

[18] or

[19] , wherein the plant-derived linear low-density polyethylene resin has a density of 0.91 g / cm 3 to 0.93 g / cm 3 , preferably a density of 0.915 g / cm 3 to 0.93 g / cm 3 .

[0154]

[21] The extrusion molded article according to [5], [9],

[18] ,

[19] or

[20] , wherein the plant-derived linear low-density polyethylene resin has a melt flow rate of 0.1 g / 10 min to 10 g / 10 min, preferably a melt flow rate of 1 g / 10 min to 5 g / 10 min.

[0155]

[22] The extrusion molded article according to any one of [1] to

[21] , wherein the plant is sugarcane.

[0156]

[23] The extrusion molded article according to any one of [1] to

[22] , wherein the extrusion molded article contains the plant-derived polyethylene resin in an amount of more than 40 mass%.

[0157]

[24] The extrusion molded article according to any one of [1] to

[23] , wherein the extrusion molded article contains the plant-derived polyethylene resin in an amount of 50 mass% or more, preferably 60 mass% or more, more preferably 70 mass% or more.

[0158]

[25] The extrusion molded article according to any one of [1] to

[24] , wherein the extrusion molded article contains the plant-derived polyethylene resin in an amount of 50 mass% to 85 mass%, preferably 60 mass% to 85 mass%, more preferably 70 mass% to 85 mass%.

[0159]

[26] The extrusion molded article according to any one of [1] to

[25] , wherein each of the first adhesive layer and the second adhesive layer contains an acid-modified polyethylene resin.

[0160]

[27] The extrusion molded article according to

[26] , wherein the acid-modified polyethylene resin is a polyethylene resin modified with an unsaturated carboxylic acid or an acid anhydride thereof.

[0161]

[28] The extrusion molded article according to

[27] , wherein the unsaturated carboxylic acid or anhydride thereof is selected from the group consisting of acrylic acid, methacrylic acid, a-ethylacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, chloromaleic acid, butenylsuccinic acid, and anhydrides thereof.

[0162]

[29] The extrusion molded article according to any one of

[26] to

[28] , wherein the acid-modified polyethylene resin is a maleic anhydride-modified polyethylene resin.

[0163]

[30] The extrusion molded article according to any one of

[26] to

[29] , wherein the acid-modified polyethylene resin is a maleic anhydride-modified polyethylene resin derived from petroleum.

[0164]

[31] The extrusion molded article according to any one of

[26] to

[30] , wherein the acid-modified polyethylene resin is a maleic anhydride-modified low-density polyethylene resin derived from petroleum, a maleic anhydride-modified linear low-density polyethylene resin derived from petroleum, or a mixture thereof.

[0165]

[32] The extrusion molded article according to

[31] , wherein the maleic anhydride-modified low-density polyethylene resin has a density of 0.91 g / cm 3 ~ 0.93 g / cm 3 , preferably a density of 0.915 g / cm 3 ~ 0.93 g / cm 3 , the maleic anhydride-modified linear low-density polyethylene resin has a density of 0.91 g / cm 3 ~ 0.93 g / cm 3 , preferably a density of 0.915 g / cm 3 ~ 0.93 g / cm 3 .

[0166]

[33] The extrusion molded article according to

[31] or

[32] , wherein the maleic anhydride-modified low-density polyethylene resin has a melt flow rate of 0.1 g / 10 minutes ~ 10 g / 10 minutes, preferably a melt flow rate of 1 g / 10 minutes ~ 5 g / 10 minutes, the maleic anhydride-modified linear low-density polyethylene resin has a melt flow rate of 0.1 g / 10 minutes ~ 10 g / 10 minutes, preferably a melt flow rate of 1 g / 10 minutes ~ 5 g / 10 minutes.

[0167]

[34] The extrusion molded article according to any one of [1] to

[33] , wherein the intermediate layer contains a resin having gas barrier properties.

[0168]

[35] The extrusion molded article according to

[34] , wherein the resin is an ethylene-vinyl alcohol copolymer resin (EVOH), a nylon (NY), a polyvinyl alcohol (PVA), a polyacrylonitrile (PAN), or a polyvinylidene chloride (PVDC).

[0169]

[36] The extrusion molded article according to

[34] or

[35] , wherein the resin is an ethylene-vinyl alcohol copolymer resin.

[0170]

[37] The extrusion molded article according to any one of [1] to

[36] , wherein the extrusion molded article has a cylindrical shape or an elliptical cylindrical shape.

[0171]

[38] The extrusion molded article according to any one of [1] to

[37] , wherein the extrusion molded article has a circumference of 30 to 190 mm, preferably 40 to 160 mm.

[0172]

[39] The extrusion molded article according to any one of [1] to

[38] , wherein the extrusion molded article has a thickness of 0.19 to 0.55 mm, preferably 0.24 to 0.5 mm.

[0173]

[40] The extrusion molded article according to any one of [1] to

[39] , wherein the innermost layer has a thickness of 0.12 to 0.25 mm, preferably 0.14 to 0.24 mm, and the outermost layer has a thickness of 0.06 to 0.2 mm, preferably 0.08 to 0.18 mm.

[0174]

[41] The extrusion molded article according to any one of [1] to

[40] , wherein the intermediate layer has a thickness of 0.01 to 0.1 mm, preferably 0.02 to 0.08 mm.

[0175]

[42] The extrusion molded article according to any one of [1] to

[41] , wherein the first adhesive layer has a thickness of 0.001 to 0.03 mm, preferably 0.005 to 0.02 mm, and the second adhesive layer has a thickness of 0.001 to 0.03 mm, preferably 0.005 to 0.02 mm.

[0176]

[43] A molded article for a pipe container, comprising:

[0177] the extrusion molded article according to any one of [1] to

[42] ; and

[0178] one or more layers provided on the extrusion molded article.

[0179]

[44] A pipe container, comprising:

[0180] a container body including the extrusion molded article of any one of [1] to

[42] whose one end is sealed; and

[0181] a cap fitting portion engaged with the other end of the extrusion molded article whose one end is sealed.

[0182]

[45] A tube container provided with:

[0183] a container body including the molded article of

[43] whose one end is sealed; and

[0184] a cap fitting portion engaged with the other end of the molded article whose one end is sealed.

[0185] Examples

[0186] [Example 1]

[0187] [1-1] Manufacture of extrusion molded article

[0188] As the resins for the innermost layer and the outermost layer, the following resins A to G were prepared.

[0189] Resin A: low-density polyethylene derived from petroleum (density: 0.92 g / cm 3 , MFR: 1.9 g / 10 min (190°C, 21.18 N load) (hereinafter referred to as "petroleum LDPE");

[0190] Resin B: low-density polyethylene derived from plants (density: 0.923 g / cm 3 , MFR: 2.7 g / 10 min (190°C, 21.18 N load) (hereinafter referred to as "biomass LDPE");

[0191] Resin C: linear low-density polyethylene derived from plants (density: 0.916 g / cm 3 , MFR: 2.3 g / 10 min (190°C, 21.18 N load) (hereinafter referred to as "biomass L-LDPE-1");

[0192] Resin D: maleic anhydride-modified low-density polyethylene derived from petroleum (density: 0.93 g / cm 3 , MFR: 1.0 g / 10 min (190°C, 21.18 N load) (hereinafter referred to as "MA-modified LDPE-1");

[0193] Resin E: maleic anhydride-modified low-density polyethylene derived from petroleum (density: 0.92 g / cm 3 , MFR: 1.5 g / 10 min (190°C, 21.18 N load) (hereinafter referred to as "MA-modified LDPE-2");

[0194] Resin F: straight-chain low-density polyethylene derived from plants (density: 0.916 g / cm3, MFR: 1.0 g / 10 min (190°C, 21.18 N load)) (hereinafter referred to as "biomass L-LDPE-2"); 3

[0195] Resin G: straight-chain low-density polyethylene derived from petroleum (density: 0.925 g / cm3, MFR: 1.9 g / 10 min (190°C, 21.18 N load)) (hereinafter referred to as "petroleum L-LDPE"). 3

[0196] As the adhesive resin for the first adhesive layer and the second adhesive layer, a maleic anhydride-modified low-density polyethylene derived from petroleum (density: 0.93 g / cm3, MFR: 1.0 g / 10 min (210°C, 21.18 N load)) was prepared. 3

[0197] As the resin for the intermediate layer (barrier layer), an ethylene-vinyl alcohol copolymer (density: 1.14 g / cm3, MFR: 12.0 g / 10 min (210°C, 21.18 N load)) was prepared. 3

[0198] Example 1

[0199] As the resin constituting the innermost layer and the outermost layer, "petroleum LDPE" was used. To 100 parts by mass of "petroleum LDPE", 0.1 part by mass of an antioxidant and 2.5 parts by mass of titanium oxide as a coloring pigment were added to obtain a mixture. The pellets of the mixture, the pellets of the adhesive resin, and the pellets of the ethylene-vinyl alcohol copolymer were respectively fed to three hoppers of a single-screw extruder. The set temperature of the extruder and the die was set to 170 to 200°C, and a pipe having a five-layer structure of innermost layer / first adhesive layer / intermediate layer / second adhesive layer / outermost layer was molded under molding conditions of a production speed of 60 roots per minute and a take-up speed of 10.8 m per minute.

[0200] The circumference of the obtained pipe (i.e., the extrusion-molded product) was 157 mm, the length was 180 mm, and the average wall thickness was 0.46 mm. In addition, the thicknesses of the innermost layer, the first adhesive layer, the intermediate layer, the second adhesive layer, and the outermost layer were 0.225 mm, 0.01 mm, 0.04 mm, 0.01 mm, and 0.175 mm, respectively.

[0201] Example 2

[0202] A pipe having a five-layer structure was manufactured in the same manner as in Example 1, except that "biomass LDPE" was used as the resin constituting the innermost layer and the outermost layer.​​​​

[0203] Example 3

[0204] A pipe having a 5-layer structure was produced in the same manner as in Example 1, except that "biomass L-LDPE-1" was used as the resin constituting the innermost layer and the outermost layer.

[0205] Example 4

[0206] In Example 4, a pipe having a 3-layer structure was produced. As the resin constituting the innermost layer and the outermost layer, a mixed resin obtained by dry blending "MA-modified LDPE-1", "MA-modified LDPE-2", and "biomass L-LDPE-2" at a mass ratio of 50:20:30 was used. To 100 parts by mass of the mixed resin, 0.1 parts by mass of an antioxidant and 2.5 parts by mass of titanium oxide as a coloring pigment were added to obtain a mixture. The pellets of the mixture and the pellets of ethylene-vinyl alcohol copolymer were respectively fed to the two hoppers of the single-screw extruder. The set temperature of the extruder and the die was set to 170 to 200°C, and a pipe having a 3-layer structure of innermost layer / intermediate layer / outermost layer was molded under molding conditions of a production speed of 60 roots / minute and a take-up speed of 10.8 m / minute.

[0207] The circumference of the obtained pipe (i.e., the extrusion-molded article) was 157 mm, the length was 180 mm, and the average wall thickness was 0.46 mm. In addition, the thicknesses of the innermost layer, the intermediate layer, and the outermost layer were 0.225 mm, 0.06 mm, and 0.175 mm, respectively.

[0208] Example 5

[0209] As the resin constituting the innermost layer and the outermost layer, a mixed resin obtained by dry blending "biomass LDPE" and "biomass L-LDPE-1" at a mass ratio of 50:50 was used, and a pipe having a 5-layer structure was produced in the same manner as in Example 1, except for this.

[0210] Example 6

[0211] As the resin constituting the innermost layer and the outermost layer, a mixed resin obtained by dry blending "biomass LDPE" and "petroleum L-LDPE" at a mass ratio of 85:15 was used, and a pipe having a 5-layer structure was produced in the same manner as in Example 1, except for this.

[0212] Example 7

[0213] As the resin constituting the innermost layer and the outermost layer, a mixed resin obtained by dry blending "biomass LDPE" and "biomass L-LDPE-1" at a mass ratio of 70:30 was used, and a pipe having a 5-layer structure was produced in the same manner as in Example 1, except for this.

[0214] Example 8

[0215] As the resin constituting the innermost layer and the outermost layer, a mixed resin obtained by dry blending "biomass LDPE" and "petroleum L-LDPE" at a mass ratio of 70:30 was used, and a pipe having a 5-layer structure was produced by the same method as in Example 1, except for this.

[0216] Example 9

[0217] As the resin constituting the innermost layer and the outermost layer, a mixed resin obtained by dry blending "petroleum LDPE" and "biomass L-LDPE-1" at a mass ratio of 30:70 was used, and a pipe having a 5-layer structure was produced by the same method as in Example 1, except for this.

[0218] [1-2] Evaluation method

[0219] The physical properties of the pipes of Examples 1 to 9 were evaluated by the following method.

[0220] <Stress cracking resistance>

[0221] One end of the obtained pipe was heat-sealed, and then a portion 5 cm from the end was cut out as a test piece. The test piece was immersed in a 10% Igepal (poly(oxyethylene) nonylphenyl ether) aqueous solution, and stored in a constant-temperature bath at 65°C for a given time. After storage, the presence or absence of cracks was determined visually.

[0222] ·Evaluation criteria

[0223] O: no cracks after storage for 24 hours

[0224] Δ: slight cracks observed after storage for 6 hours

[0225] X: large cracks observed after storage for 6 hours (up to leakage of the contents)

[0226] <Ultrasonic sealing strength>

[0227] An ultrasonic sealing machine (BRANSON TS-2, power supply 2000X) was used to seal the sample under sealing conditions of amplitude 90%, and welding time: 200 msec, and then the sample was evaluated by the following method. The sealed sample was cut into a long strip 15 mm wide as a test piece. The sealed portion of the test piece was opened to 180°, and mounted on the grips of a tensile testing machine (SHIMADZU, trade name AUTOGRAPH AGS-X). A T-type tensile test was performed at a tensile speed of 50 mm / min, and the steady value was taken as the ultrasonic sealing strength [N].

[0228] ·Evaluation criteria

[0229] O: 35N or more

[0230] Δ: 23N or more and less than 35N

[0231] X: less than 23N

[0232] <Surface roughness>

[0233] The rough state of the surface of the obtained tube was visually confirmed.

[0234] • Evaluation criteria

[0235] O: no roughness

[0236] Δ: slightly rough

[0237] X: obvious roughness

[0238] <Biomass degree>

[0239] The proportion (%) of the plant-derived polyethylene resin contained in the obtained tube, i.e., the "biomass degree," was calculated by the following formula.

[0240] Biomass degree (%) = {(total mass of plant-derived polyethylene resins) / (total mass of all resins constituting the extrusion molded article)} x 100

[0241] [1-3] Evaluation results

[0242] The "resin composition of the innermost layer and the outermost layer" and the "evaluation results" of the tubes of Examples 1 to 9 are shown in Table 1 below. The value of "blending amount" in the table indicates parts by mass, and the value of "ultrasonic sealing strength" indicates Newton.

[0243] [Table 1]

[0244]

[0245] The tube of Example 1 had a 5-layer structure of innermost layer / first adhesive layer / intermediate layer / second adhesive layer / outermost layer, and the innermost layer and the outermost layer were each composed of a petroleum-derived polyethylene resin, and did not contain a plant-derived polyethylene resin. The tube of Example 1 showed good results in the stress cracking resistance test, the ultrasonic sealing strength test, and the surface roughness test.

[0246] The tubes of Examples 2 and 3 had the same 5-layer structure as Example 1, and the innermost layer and the outermost layer were each composed of a plant-derived polyethylene resin. The tube of Example 2 was more likely to generate a stress crack than the tube of Example 1, and a tendency of a decrease in sealing strength was observed, but both were at a level that was not a problem in practice. In addition, the tube of Example 3 showed a slight roughness on the surface compared to the tube of Example 1, but was at a level that was not a problem in practice.

[0247] The innermost layer and the outermost layer of the pipe of Example 4 each are composed of a plant-derived polyethylene resin and a bonding resin, and has a three-layer structure of innermost layer / intermediate layer / outermost layer. The pipe of Example 4 showed good results in the stress cracking resistance test, the ultrasonic sealing strength test, and the surface roughness test. However, the pipe of Example 4, because the bonding resin is incorporated into the innermost layer and the outermost layer, the bonding resin is diluted, and a large amount of the bonding resin is used. Therefore, the pipe of Example 4 has a lower biomass degree than the pipes of the five-layer structure (Examples 2, 3, 5 to 8).

[0248] The pipes of Examples 5 and 7 have the same five-layer structure as Example 1, and the innermost layer and the outermost layer each are composed of a plant-derived low-density polyethylene resin and a plant-derived linear low-density polyethylene resin. The pipes of Examples 5 and 7 each showed good results in the stress cracking resistance test, the ultrasonic sealing strength test, and the surface roughness test.

[0249] The pipes of Examples 6 and 8 have the same five-layer structure as Example 1, and the innermost layer and the outermost layer each are composed of a plant-derived low-density polyethylene resin and a petroleum-derived linear low-density polyethylene resin. The pipes of Examples 6 and 8 each showed good results in the stress cracking resistance test, the ultrasonic sealing strength test, and the surface roughness test.

[0250] The pipe of Example 9 has the same five-layer structure as Example 1, and the innermost layer and the outermost layer each are composed of a petroleum-derived low-density polyethylene resin and a plant-derived linear low-density polyethylene resin. The pipe of Example 9 showed good results in the stress cracking resistance test, the ultrasonic sealing strength test, and the surface roughness test.

[0251] Explanation of symbols

[0252] 1… extrusion molded article, la… innermost layer, lb… first bonding layer, lc… intermediate layer, Id… second bonding layer, le… outermost layer, 10… pipe container, 11… container main body, 12… cap fitting portion, 21… main body portion, 22… sealing portion, 31… shoulder portion, 32… mouth portion.

Claims

1. An extrusion molded article for a tube container, which has a tubular shape as a whole without a joint, the extrusion molded article has a 5-layer structure in which an innermost layer, a first adhesive layer, an intermediate layer, a second adhesive layer, and an outermost layer are sequentially laminated, the innermost layer and the outermost layer each contain a low-density polyethylene resin and a linear low-density polyethylene resin, at least one of the low-density polyethylene resin and the linear low-density polyethylene resin being derived from a plant.

2. The extrusion molded article according to claim 1, wherein the innermost layer and the outermost layer each contain a low-density polyethylene resin derived from a plant and a linear low-density polyethylene resin derived from a plant.

3. The extrusion molded article according to claim 1, wherein the innermost layer and the outermost layer each contain a low-density polyethylene resin derived from a plant and a linear low-density polyethylene resin derived from petroleum.

4. The extrusion molded article according to claim 1, wherein the innermost layer and the outermost layer each contain a low-density polyethylene resin derived from petroleum and a linear low-density polyethylene resin derived from a plant.

5. The extrusion molded article according to any one of claims 1 to 4, wherein the innermost layer and the outermost layer each contain the low-density polyethylene resin and the linear low-density polyethylene resin at a mass ratio of 9: 1 to 1:

9.

6. The extrusion molded article according to any one of claims 1 to 4, wherein the extrusion molded article contains a polyethylene resin derived from a plant in an amount of more than 40 mass%.

7. The extrusion molded article according to any one of claims 1 to 4, wherein the first adhesive layer and the second adhesive layer each contain an acid-modified polyethylene resin.

8. The extrusion molded article according to claim 7, wherein the acid-modified polyethylene resin is a maleic anhydride-modified polyethylene resin.

9. The extrusion molded article according to any one of claims 1 to 4, wherein the intermediate layer contains a resin having gas barrier properties.

10. The extrusion molded article according to claim 9, wherein the resin is an ethylene-vinyl alcohol copolymer resin.

11. A molded article for a tube container, comprising: the extrusion molded article according to any one of claims 1 to 10, and one or more layers provided on the extrusion molded article.

12. A tube container, comprising: a container main body containing the extrusion molded article according to any one of claims 1 to 10 with one end sealed or the molded article according to claim 11 with one end sealed; and a cap fitting portion engaged with the other end of the extrusion molded article with one end sealed or the molded article with one end sealed.

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