JP2015134630A - Synthetic resin-made blow-molding multilayer container having annular expansion portion on upper end of shoulder part and including carbon-labeled surface layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blow-molding container which contributes to the visibility of a COdischarge amount and can be surely and stably gripped during production.SOLUTION: A synthetic resin-made blow-molding multilayer container comprises a mouth part, annular recess, shoulder, body and bottom, and is composed by the inner surface layer containing an ethylenic resin, a barrier layer and an outer surface layer containing the ethylenic resin in this order from the inside of the container. The mouth part has an external thread area on an outer peripheral face, and the annular recess is contracted in diameter from the external thread area and then, is expanded in diameter to link to the shoulder. The container has an annular expansion portion formed in the upper end of the shoulder by curving the surface of the container inside in the inner surface layer facing the container outside along the axial direction of the container and then curving facing the container inside, and having the thickness of 20-55% with respect to the thickness of the mouth part. Besides, one or both of the surface layers contain at least one of the synthetic resins of low density polyethylene, ethylene/α-olefin copolymer having a density of 912-935 kg/mor high density polyethylene, and comprise the resin compositions having the modern carbon ratio based on ASTM D6866-12 of 0-8 pMC (percent modern carbon). The surface layer is carbon-labeled.

Description

The present invention relates to a synthetic resin container manufactured by blow molding, that is, a synthetic resin blow molded multilayer container, and more particularly to a synthetic resin direct blow molded multilayer container. More specifically, it is made of a synthetic resin that has a mouth, an annular recess, a shoulder, a trunk, and a bottom, and has an annular bulging part with a specific configuration that contributes to the visualization of CO ₂ emissions. The present invention relates to a blow molded multilayer container.

  As a synthetic resin container filled with a liquid content, a blow molded container obtained by molding a parison or a preform into a container shape with a pressurized gas or the like in a mold is known, particularly a multilayer synthetic resin. Blow molded containers, that is, synthetic resin blow molded multilayer containers are widely used. As a layer structure of the blow molded multilayer container made of synthetic resin, as a surface layer (outer layer and / or inner layer), polyolefin resin such as polyethylene, polypropylene or olefin copolymer, polyester resin such as polyethylene terephthalate, polyamide resin such as nylon, etc. A multilayer structure having a barrier layer such as an ethylene / vinyl alcohol copolymer (EVOH) or a polyvinylidene chloride resin is widely used as an intermediate layer (core layer). Furthermore, a synthetic resin blow molded multilayer container including an adhesive layer and a layer containing scrap (recovery layer) is known.

  In particular, a synthetic resin blow-molded multilayer container filled with viscous contents such as mayonnaise, ketchup, sauce, etc. is a cylindrical synthetic resin parison melt-extruded, followed by a mold inner wall surface at a predetermined temperature In many cases, it is manufactured by direct blow molding (sometimes referred to as “extrusion blow molding”) in which blow molding is performed by regulating the shape. As disclosed in Patent Document 1 and Patent Document 2, at least an inner surface layer containing an ethylene-based resin, a barrier layer, and an outer surface layer containing an ethylene-based resin are provided in this order from the inside of the container. A synthetic resin blow molded multilayer container (synthetic resin direct blow molded multilayer container) produced by molding is known.

  A synthetic resin blow molded multilayer container filled with contents such as food (hereinafter sometimes referred to as “blow molded multilayer container” or “multilayer container”) includes a container molding process (blow molding), and a container transfer process. The final product is manufactured through a content filling process such as food by a user, a mouth sealing process after filling the contents, a cap mounting process, a sterilization process, a container packaging process, and the like.

  In the content filling process, for example, a blow molded multilayer container having a mouth part, an annular recess, a shoulder part, a trunk part, and a bottom part, which is molded in the container molding process, is filled with contents such as food, as necessary. After performing heating, sterilization, and cooling and checking the filling amount, etc., the container is transferred to the mouth seal device. In the mouth sealing step, the mouth opening of the multilayer container is sealed with a sealing material to form a sealed container. Next, the sealed containers are transferred to a cap mounting device (also referred to as “capper”) while aligning the sealed containers. In the cap mounting process, the cap mounting device rotates and winds the cap around the mouth of the sealed container. Tighten.

  The transfer of the multi-layer container between the processes after the container molding is usually performed while delivering the multi-layer container using a rotating conveyance wheel. For example, after filling the contents into the multi-layer container, the filling amount and the filling weight are inspected, and the multi-layer container not satisfying the standard range is discharged out of the process. In this way, the discontinuous arrangement of the multilayer containers is arranged in a continuous arrangement, that is, arranged at regular intervals, and the filled multilayer containers (filling containers) satisfying the standard range are aligned, and then passed through the delivery wheel. Then, the filling container is delivered to the mouth sealing process.

  Multi-layer container delivery is performed by continuously gripping multi-layer containers (filled containers, etc.) arranged at equal intervals on the upper surface of a transport wheel (also referred to as a delivery wheel, a rotation station, etc.) with a gripping means. This is performed by switching the gripping by the gripping means between the transporting wheels. Thus, the multilayer container is transferred to the next step while maintaining the multilayer container (filling container or the like) in an upright state or a predetermined posture state. In order to help maintain the container in an upright state, each conveyance wheel can be provided with a guide plate or a guide groove.

  In the mouth sealing step, the filling container rotates on the transport wheel while being gripped by the gripping means. When the filling container reaches just below the sealing device, the upper part of the filling container is gripped, and the filling container is brought into an upright state (i.e., the container is in the vertical direction toward the top of the horizontal ground with the bottom of the container as the ground side). In a fixed state (with the shaft in place), a lid (sealing material) having a thermal adhesive layer such as low-density polyethylene is usually supplied to the lower surface, placed on the opening of the filling container, and heated from above. By pressure, a lid is welded to the opening of the filling container to form a sealed container. By using a lid material (seal material) provided with a metal thin film such as aluminum and applying high-frequency induction heating while pressing from above, the lid material can be welded to the opening of the filling container.

  In recent years, in order to improve productivity, the speed of manufacturing apparatuses for synthetic resin containers is increasing. When the angular velocity of rotation increases, centrifugal force increases, and mechanical vibration accompanying rotation may be received, or a difference may occur in inertial force received by a container (filled container or the like) between adjacent conveyance wheels. As a result, the container (filling container or the like) may swing or tilt in various directions, and for example, the mouth seal by the sealing device may not be accurate. In some cases, it may fall over. For this reason, gripping containers (filling containers, etc.) is becoming increasingly important.

  As a means for gripping a container (filled container or the like) after forming the container, a means for supporting the container by gripping the body or bottom of the container is known, but depending on the size of the container and the shape of the body, etc. Since it is necessary to update the gripping means, adjust the position, etc., it takes time and increases the cost. Therefore, various gripping means for supporting the container by gripping the upper part (mouth, shoulder, etc.) of the container (filling container etc.) are known. Patent Document 3 discloses a support member that is inserted into the lower surface side of a flange formed below a screw thread formed in the mouth portion and supports the upper portion of the container across the mouth portion of the container from the left-right direction, and the corresponding outer shape of the container. The shape is disclosed. In Patent Document 4, the container is supported by inserting the upper neck ring and the lower neck ring below the threaded portion (male thread region) formed in the mouth portion into the space below each of the upper neck ring and the upper part of the container. The container conveying device for delivering and receiving the container by the gripper and the outer shape of the corresponding container are disclosed. Patent Document 5 discloses a container gripper provided with a neck support for positioning the container mouth portion and the gripper in addition to a neck holder for holding the container mouth portion, and an outer shape of the corresponding container. Furthermore, Patent Document 6 discloses a container in which a cap-tightening turnip, a protrusion, and a neck ring are sequentially provided on the outer periphery of a cylindrical portion that forms a spout.

  The flange, cabra or neck ring formed below the threaded portion (male thread region) of the mouth of the container is a gripping means for supporting the upper part of the container, that is, a gripper (specifically, In order to support the container by inserting a fork-like gripper fork or the like, the strength is generally given as a solid, and the parison is mainly formed by injection molding. When a flange is formed by injection molding, a mold portion corresponding to the flange portion includes a cavity surface that protrudes in the outer wall direction along the shape of the flange, along with a cavity surface that makes the inner wall surface of the container parallel to the container axial direction. Thus, when the injected molten resin fills the cavity in the mold, the formed flange is formed as a solid part having a cross section filled with the resin. When the container is supported by the gripper, an operation of inserting into a predetermined location such as a flange (hereinafter sometimes referred to as “gripper receiving portion”) and then removing it is required. Therefore, the upper surface, the lower surface, and the tip of the gripper may come into contact with or slide on the gripper receiving portion of the container. There are grippers such as a fork that sandwiches the upper part of the container from the left and right, and a fork that rotates around one fulcrum, but it comes into contact with or slides on the gripper receiving part of the container. Are common. As the speed of the synthetic resin container manufacturing apparatus increases, a large centrifugal force acts on the filled container filled with the contents. As a result, the container (filled container) supported by the gripper is in an upright state. In some cases, it may be difficult to maintain a predetermined posture state, and the possibility that the mouth seal is not accurate or the container falls down is further increased.

  For this reason, attempts have been made to stabilize and reliably hold the container with the gripper by controlling the shape of the upper part of the blow molded multilayer container made of synthetic resin, particularly the shape near the gripper receiving portion. Specifically, it is conceivable to strictly control the outer surface shape of the portion from the mouth portion to the trunk portion. However, for example, a direct blow molded multilayer container made of synthetic resin has a cylindrical synthetic resin parison melt-extruded and subsequently blow molded into a container shape in a mold at a predetermined temperature. It is considered that adjusting the melt extrusion conditions and blow molding conditions to strictly control the outer surface shape requires excessive trial and error.

  In addition, a lubricant (slip agent) is conventionally added to the raw material resin in order to improve the slipperiness of the synthetic resin blow-molded multilayer container in transportation between various processes after container molding and transportation of filled container products. Has also been done. The lubricant is usually added to a raw material resin by a master batch method or kneaded. When the synthetic resin container is a multilayer container, a lubricant is often added to the surface layer (inner surface layer or outer surface layer). As the lubricant, an organic lubricant, for example, an unsaturated fatty acid amide such as oleic acid amide or erucic acid amide, a saturated fatty acid amide such as stearic acid amide or behenic acid amide (behenic acid amide), or an inorganic lubricant such as silica is used. The These lubricants are also used by mixing two or more kinds.

  Therefore, as the production of blow molded containers made of synthetic resin is accelerated, gripping by gripper insertion is stably and reliably performed in the transportation between various processes including the mouth sealing process after filling the contents after container molding. There has been a demand for a synthetic resin blow molded multilayer container, particularly a synthetic resin direct blow molded multilayer container, which can be implemented and can maintain an upright state or a predetermined posture state of the container (filled container).

[Container recycling]
On the other hand, various types of containers such as blow molded multilayer containers made of synthetic resin occupy the majority of household waste by volume ratio, and recycling and sorting are progressing due to the growing public opinion of building a recycling society. Combined with the enactment of the Containers and Packaging Recycling Law and the Law for Promotion of Effective Utilization of Resources, the recycling rate of aluminum containers and PET bottles has been improved and the resource reuse rate has also improved, but there are few cases where it is finally burned. Absent.

[Carbon offset]
When a synthetic resin such as an ethylene resin that is an organic substance or a molded product such as a container or a cap made of the synthetic resin material is burned, carbon dioxide is generated. Carbon dioxide is one of the gases that warm the global environment, that is, greenhouse gas (also called “green house gas”), and has continued to increase along with industrial activities by people, especially after the industrial revolution. . In order to maintain a global environment where human survival is sustainable, the concept of carbon dioxide that does not increase the total amount of carbon dioxide circulating in the earth's oceans and atmosphere is shared.

  Currently, most synthetic resin materials, such as ethylene-based resins, are produced using compounds derived from fossil fuels such as petroleum, coal, and natural gas as starting materials. Fossil fuels contain carbon that has been fixed in the ground for many years. Combustion of a fossil fuel or a product derived from a compound derived from fossil fuel and releasing carbon dioxide into the atmosphere means that carbon that is fixed deep in the ground and does not exist in the atmosphere will Since it is suddenly released into the atmosphere as carbon, carbon dioxide in the atmosphere greatly increases, causing global warming.

  On the other hand, even if organisms (plants, animals) that grow while absorbing carbon dioxide circulating in the global environment are burned in the earth's atmosphere to generate carbon dioxide, it is a circulation of carbon dioxide that exists in the global environment. There is no change in the total amount of carbon that constitutes the carbon dioxide. This carbon entry / exit is said to be a state of carbon offset (carbon offset) or no entry / exit (carbon neutral), and carbon negative (carbon negative) increases carbon dioxide present in the global environment. ).

  Carbon that circulates in the global environment, and the existing carbon is renewable carbon, modern carbon (contemporary carbon), bio-derived carbon (bio-resourced carbon, biobased carbon, biogenic carbon) , Bio-origin carbon), biomass derived carbon, green carbon, atmospheric carbon, environmentally friendly carbon, or life-cycle carbon, etc. It is distinguished from fossil carbon (fossil carbon, fossil fuel based carbon, petrochemical based carbon, carbon of fossil origin).

  In particular, plants are organisms that grow by absorbing carbon dioxide circulating in the global environment, performing photosynthesis reactions using carbon dioxide and water as raw materials, and assimilating and fixing as organisms. It is attracting attention as a source. For example, alcohol components, especially ethyl alcohol, are distilled and separated from fermented sugar or cellulose fermented products extracted from plant materials such as sugar cane and corn, and ethylene is obtained as an alkene by its dehydration reaction. Thus, an ethylene resin or an olefin resin can be obtained (Patent Document 7). Synthetic resins having this history are said to be carbon offset polyolefin, biogenic polyolefin, plant based resin, or the like.

Carbon constituting the carbon dioxide circulating in the global environment may be called radioactive carbon 14 (sometimes referred to as “ ¹⁴ C”) or stable carbon 12 (“ ¹² C”), which is an isotope. ) And metastable carbon 13 (sometimes referred to as “ ¹³ C”), the mass ratios of which are ¹² C (98.892 mass%), ¹³ C (1.18 mass%) and ¹⁴ C (a trace amount of 1.2 × 10 ⁻¹² mass% to 1.2 × 10 ⁻¹⁰ mass%). The ratio of ¹² C to ¹³ C is stable. In addition, radioactive ¹⁴ C is generated when neutrons contained in secondary cosmic rays generated by primary cosmic rays in the upper atmosphere collide with nitrogen atoms in the atmosphere (sometimes referred to as “ ¹⁴ N”). Therefore, although it fluctuates slightly depending on the intensity of sunspot activity of the sun, etc., it is always supplied, while it decreases with a half-life of 5730 years.

Living organisms (plants and animals) that grow while continuously absorbing carbon dioxide circulating in the global environment continue to inherit the mass ratio of the three types of carbon isotopes that make up the carbon dioxide circulating in the global environment. When the organism is killed, the mass ratio of the three types of carbon isotopes inside the organism is fixed at the ratio at the time of death. The half-life of ¹⁴ C is 5730 years, and archaeological dating methods that use this to estimate the age of various samples are well known. On the other hand, ¹⁴ C in fossil fuels for a long time is formed elapsed since killing of organisms inhabit the ancient a long time ago than the half-life 5730 years of ¹⁴ C, a modern circulating in the global environment carbon dioxide When measured in isolation, it can be regarded as almost 0 (below the detection limit of the measuring instrument), so that ¹⁴ C in the synthetic resin derived from fossil fuel can be regarded as almost 0.

Therefore, it is possible to distinguish between a synthetic resin derived from a plant and a synthetic resin derived from a fossil fuel by the ratio of ¹⁴ C contained. It is necessary to harvest a growing plant, saccharify it into alcohol, and use ethylene produced by the dehydration reaction as a raw material to produce a plant-derived synthetic resin through ordinary resin synthesis means. The time is about several months and can be neglected from the half-life of ¹⁴ C, 5730 years. There is no substantial effect on the determination.

The ratio of radioactive ¹⁴ C composing carbon dioxide circulating in the global environment has been diluted and reduced by humans burning large amounts of fossil fuels since the Industrial Revolution, but the atmosphere since 1950 AD It turned to increase by the inner core experiment. That is, the amount of radioactive ¹⁴ C produced by atmospheric nuclear tests exceeded the amount of radioactive ¹⁴ C produced by the nuclear reaction of ¹⁴ N caused by collision with neutrons produced by the action of cosmic rays. Subsequently, due to the 1964 nuclear test cessation treaty, the ratio of radioactive ¹⁴ C began to decrease after peaking in 1963, and the ratio of radioactive ¹⁴ C in 1950 changed, although there were fluctuations due to subsequent accidents at nuclear power plants. It has not reached.

Therefore, for the distinction between plant-derived synthetic resins and fossil fuel-derived synthetic resins, a standardization method based on the abundance ratio of radioactive ¹⁴ C as of 1950 is known, and the US National Bureau of Standards (NIST) ) By ASTM D6866-12 (Determining the Biobased Control of Solid, Liquid, and Gaseous Samples Using Radiocarbon Analysis). ASTM D6866 is an ASTM (American Society for Testing and Materials) standard that determines the biogenic carbon concentration in solid, liquid, and gas samples using radiocarbon dating. Since it was approved, it has been revised and the current latest standard ASTM D6866-12 is the one revised in April 2012.

The principle defined by ASTM D6866-12 is roughly as follows. In other words, organic substances derived from fossil fuels have been killed or cut off by living organisms (animals and plants) in the era before 1950, and the ratio composition of carbon isotopes at that time is fixed. The abundance ratio of carbon constituting the organic substance is 0 (zero). Therefore, the ratio composition of carbon isotopes is derived from fossil fuel using the unit of modern carbon ratio (percent modern carbon: pMC) defined by the function of ¹³ C / ¹² C, which is a stable ratio, and radioactive ¹⁴ C. The modern carbon ratio of the organic substance is set to 0 pMC (meaning less than the detection limit of the measuring instrument). Further, the modern carbon ratio of a standard substance (oxalic acid supplied by NIST (SRM4990) or an equivalent organic substance) having a carbon isotope ratio composition as of 1950 is defined as 100 pMC. The ratio of the fossil fuel-derived organic substance and the plant-derived organic substance is determined by determining the modern carbon ratio of the sample with reference to 0 to 100 pMC. The modern carbon ratio of the plant-derived synthetic resin produced at present is not lower than at least 102 pMC due to the influence of ¹⁴ C which has been artificially increased by atmospheric nuclear tests conducted since 1950, and is about 107 pMC on average. is there. The modern carbon ratio in 1963 before the nuclear test termination treaty, at which the ratio of ¹⁴ C was the peak, was 118 pMC. Therefore, if the modern carbon ratio of the synthetic resin is 102 to 118 pMC, it can be said that it is a plant-derived synthetic resin.

  Moreover, from the value of the modern carbon ratio of the known plant-derived synthetic resin, a synthetic resin material (a modern carbon ratio is 0 pMC) that is a mixture of the plant-derived synthetic resin and a fossil fuel-derived synthetic resin ( The content ratio of the plant-derived synthetic resin in the resin composition) can be calculated, and the mass ratio of the plant-derived synthetic resin may be described as “% Corg.renew”. For example, the mass ratio of the plant-derived synthetic resin (modern carbon ratio is calculated as 107 pMC × 0.96 = 102.7 pMC) and the synthetic resin derived from fossil fuel in the resin composition of 96% When the ratio is 50:50, the resin composition has a modern carbon ratio of 51.4 pMC (calculated as 107 pMC × 0.96 × 0.50 = 51.36 pMC) and 48% Corg.renew ( It is calculated as 96% × 0.5). When the mass ratio of the resin composition is 55:45, the modern carbon ratio is 56.5 pMC (calculated as 107 pMC × 0.96 × 0.55 = 56.50 pMC). 52.8% Corg.renew (calculated as 96% × 0.55). In addition, the “bioification rate” (%) is the mass ratio of the synthetic resin derived from the plant in the synthetic resin, and may be referred to as “biomass plastic degree” or “biomass degree”. If so, it is allowed to be referred to as “biomass plastic” as containing 25.0% by mass or more of biomass plastic based on the biomass plastic identification display system established by the Japan Bioplastics Association.

  As described above, the modern carbon ratio of the plant-derived synthetic resin is not lower than 102 pMC and is about 107 pMC on average, and is therefore a mixture of a certain plant-derived synthetic resin and a synthetic resin derived from fossil fuel. If the modern carbon ratio of the synthetic resin material (resin composition) is 53.5 pMC or more, the mass ratio of the plant-derived synthetic resin is calculated as 50 mass% or more (107 pMC × 0.50 = 53.5 pMC). )You can say that.

On the other hand, a resin composition containing no synthetic resin derived from plants and containing a synthetic resin derived from fossil fuels is essentially modern when measured separately from the modern carbon dioxide circulating in the global environment as described above. Although the carbon ratio is 0 pMC, in reality, radioactive ¹⁴ C derived from nuclear tests and nuclear power plant accidents conducted since 1950 are mixed, or carbon dioxide circulating in the modern global environment is the surface. Adsorbed or permeated to the carbon to cause carbon isotope exchange may cause a modern carbon ratio greater than 0 pMC. However, in many cases, the ratio of the synthetic resin modern carbon derived from fossil fuel is in the range of 0.01 to 0.03 pMC, and can be said to be substantially 0 pMC. Moreover, the modern carbon ratio of the synthetic resin derived from fossil fuel does not exceed 8 pMC. Therefore, if the modern carbon ratio of a certain synthetic resin or a resin composition containing a synthetic resin is 0 to 8 pMC, the synthetic resin or the resin composition containing the synthetic resin is derived from a fossil fuel-derived synthetic resin or a fossil fuel. It can be said that it is a resin composition containing the synthetic resin.

In addition, the influence of radioactive ¹⁴ C derived from inorganic carbon such as calcium carbonate, which is a component of limestone and may be blended in a resin composition containing a synthetic resin derived from fossil fuel for various purposes, is observed. Sometimes, in measuring modern carbon ratios, methods that eliminate the effect are standardized. In addition, in a resin composition containing a synthetic resin derived from fossil fuel, radioactive ¹⁴ C derived from an additive or compounding agent containing organic carbon is affected and diluted, so that it is larger than 0 pMC. Although a modern carbon ratio may be shown, if it is a normal compounding quantity, the modern carbon ratio of the resin composition containing the synthetic resin derived from fossil fuel will not exceed 8 pMC.

[Carbon labeling]
In recent years, environmental labeling systems have begun to spread for the purpose of contributing to environmental conservation and reduction of environmental burdens. For example, environmental management is being operated as ISO 14000, which is an international standard. Attempts to “visualize” CO ₂ emissions through the entire life cycle from the procurement of raw materials to disposal and recycling of carbon dioxide (CO ₂ ), a greenhouse gas, at the manufacturing and use stages of various products and services. This is called carbon labeling and carbon footprint display. If carbon labeling or carbon footprint display becomes widespread, operators are expected to use it as an indicator for improving product design and manufacturing process management to reduce the environmental burden in the product life cycle. It can be used as one of product selection materials, and is expected to become one of the means for promoting efforts to reduce the environmental burden of manufacturers and suppliers. In addition, carbon labeling is effective for securing credits used for carbon offsets and guaranteeing reliability and transparency, and is becoming increasingly important as environmental accounting is expected to spread in the future.

  In principle, fossil fuel-derived synthetic resins and plant-derived synthetic resins differ only in the modern carbon ratio. Except for the effects on the global environment, manufacturing resin products from these synthetic resins It is believed that there is no change or difference in handling for the process or the formed resin product. However, in reality, it is also known that there may be a difference in compatibility and mechanical properties (Patent Document 8).

JP-A 63-237924 JP-A-7-32554 JP-A-11-236123 JP 2008247474 A JP 2013-6647 A JP 2007-99381 A Special table 2010-511634 JP 2011-132525 A

The problem of the present invention is that it contributes to “visualization” of CO ₂ emissions, and as the speed of manufacturing equipment increases, gripping by gripper insertion is stable and reliable during transportation between processes after container molding. It is an object of the present invention to provide a synthetic resin blow molded multilayer container, particularly a direct blow molded multilayer container.

  As a result of diligent research on solving the above problems, the present inventors have sequentially formed a mouth portion having an external thread area on the outer peripheral surface, an annular recess portion, a shoulder portion, a trunk portion, and a bottom portion along the container axial direction. In the synthetic resin blow molded multilayer container, the layer structure of the multilayer container includes at least an inner surface layer containing an ethylene-based resin, a barrier layer, and an outer surface layer containing an ethylene-based resin in this order from the inner side of the container. Resin having an annular bulging portion having a specific structure in which the shape and thickness of the inner surface are controlled at the upper end of the shoulder connected to the recess, and at least one surface layer having a modern carbon ratio in a specific range It was found that the use of the composition could solve the problems, and the present invention was completed.

That is, according to the present invention, a synthetic resin blow-molded multilayer container comprising a mouth, an annular recess, a shoulder, a trunk, and a bottom sequentially along the container axial direction:
i) The layer constitution of the multilayer container comprises at least an inner surface layer containing an ethylene-based resin, a barrier layer and an outer surface layer containing an ethylene-based resin in this order from the inside of the container;
ii) The mouth portion has a male thread region on the outer peripheral surface;
iii) the annular recess is reduced in diameter from the male thread region and then expanded to connect to the shoulder;
iv) The shoulder includes an annular bulge at the upper end;
v) The annular bulge is formed by bending the inner surface of the inner surface layer toward the outside of the container along the container axial direction, and then bending toward the inside of the container. And having a thickness of 20-55% of the thickness of the mouth; and
vi) At least one surface layer containing an ethylene-based resin is selected from the group consisting of low-density polyethylene, an ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ , and a high-density polyethylene as a resin component. Comprising a resin composition having a modern carbon ratio of 0 to 8 pMC as defined in ASTM D6866-12;
A synthetic resin blow-molded multilayer container having a carbon-labeled surface layer is provided.

  Moreover, according to this invention, the synthetic resin blow molding multilayer container provided with the surface layer by which the carbon labeling of the following (1)-(7) was provided as an aspect.

(1) A low-density polyethylene is a high-pressure low-density polyethylene having a density of 910 to 930 kg / m ³ or a density of 910 to 928 kg / m ³ obtained by selectively copolymerizing α-olefin using a metallocene catalyst. A blow molded multilayer container made of synthetic resin, comprising the carbon-labeled surface layer containing at least one kind of low density polyethylene.
(2) A synthetic resin blow-molded multilayer container comprising the carbon-labeled surface layer formed by direct blow molding.
(3) A synthetic resin blow-molded multilayer container comprising a carbon-labeled surface layer formed of an ethylene / vinyl alcohol copolymer as a barrier layer.
(4) A synthetic resin blow-molded multilayer container including the carbon-labeled surface layer including the recovery layer.
(5) A synthetic resin blow-molded multilayer container comprising the above carbon-labeled surface layer comprising an adhesive layer between one or both of the inner surface layer and the barrier layer or between the barrier layer and the outer surface layer. .
(6) The inner surface layer containing an ethylene-based resin in the annular bulging portion is formed from an ethylene-based resin composition containing an unsaturated fatty acid amide, a saturated fatty acid amide or a mixture thereof, which is an organic lubricant. A synthetic resin blow molded multilayer container having a carbon-labeled surface layer.
(7) A synthetic resin blow molded multilayer container comprising the carbon-labeled surface layer containing a fatty acid amide having an unsaturated cis structure carbon double bond as an organic lubricant.

According to the present invention, a synthetic resin blow-molded multilayer container comprising a mouth, an annular recess, a shoulder, a trunk, and a bottom sequentially along the container axial direction:
i) The layer constitution of the multilayer container comprises at least an inner surface layer containing an ethylene-based resin, a barrier layer and an outer surface layer containing an ethylene-based resin in this order from the inside of the container; ii) Has an external thread area on the outer peripheral surface; iii) The annular recess is reduced in diameter from the external thread area and then expanded to connect to the shoulder; iv) The shoulder has an annular bulge at the upper end. V) The annular bulging portion is formed by bending the inner surface of the inner surface layer toward the outside of the container along the container axial direction, and then bending toward the inside of the container. And having a thickness of 20-55% with respect to the thickness of the mouth; and vi) at least one surface layer containing an ethylene-based resin is a low-density polyethylene, a density of 912- ethylene · alpha-olefin copolymer of 935 kg / ^{m 3,} and a high Contains at least one selected from the group consisting of degrees polyethylene, modern carbon ratio as defined in ASTM D6866-12 is made of a resin composition which is 0～8PMC;
By being a synthetic resin blow-molded multilayer container having a carbon-labeled surface layer,
Contributes to “visualization” of CO ₂ emission and speeds up the production of blow molded containers made of synthetic resin, and grips by gripper insertion stably and reliably when transporting between various processes after container molding In addition, there is an effect that a blow molded multilayer container, particularly a direct blow molded multilayer container, provided with a carbon-labeled surface layer capable of maintaining a predetermined posture state of the container is provided.

  In particular, according to the present invention, the inner surface layer containing an ethylene resin in the annular bulging portion is the synthetic resin blow-molded multilayer container formed from an ethylene resin composition containing an organic lubricant. Thus, there is an effect that a synthetic resin blow-molded multilayer container, particularly a synthetic resin direct blow-molded multilayer container, with improved slipperiness is provided.

It is a schematic front view of the mouth part-trunk part of a synthetic resin blow-molded multilayer container provided with a carbon-labeled surface layer of the present invention. It is a schematic sectional drawing of the cyclic | annular bulging part vicinity provided at the upper end of the shoulder part of the synthetic resin blow-molded multilayer container provided with the surface layer by which the carbon labeling of this invention was provided. 1 is a schematic cross-sectional view of a mouth, an annular recess, and a shoulder of a synthetic resin blow-molded multilayer container having a carbon-labeled surface layer that does not have an annular bulge according to the present invention.

I. Layer structure of a synthetic resin blow-molded multilayer container having a carbon-labeled surface layer The layer structure of a synthetic resin blow-molded multilayer container having a carbon-labeled surface layer of the present invention includes at least an ethylene-based resin. A surface layer, a barrier layer, and an outer surface layer containing an ethylene-based resin are provided in this order from the inside of the container. A synthetic resin blow-molded multilayer container comprising at least an inner surface layer containing an ethylene-based resin, a barrier layer, and an outer surface layer containing an ethylene-based resin in this order from the inside of the container is an inner surface containing an ethylene-based resin. As long as the container is provided with three layers of a surface layer, a barrier layer and an outer surface layer containing an ethylene-based resin in this order from the inside of the container, for example, one or more layers such as a recovery layer and an adhesive layer, which will be described later, This means that a multilayer container provided between three layers (may be one layer or a plurality of layers), or a multilayer container including any one of the three layers, for example, a plurality of barrier layers, may be used. .

The blow molded multilayer container made of a synthetic resin having a carbon-labeled surface layer according to the present invention includes an inner surface layer containing an ethylene-based resin (hereinafter sometimes simply referred to as “inner surface layer”), and ethylene described later. As for the surface layer which is an outer surface layer containing a resin (hereinafter sometimes simply referred to as “outer surface layer”), at least one of the surface layers is a low-density polyethylene having a density of 912 to 935 kg / m as a resin component. ^3. A resin composition comprising at least one selected from the group consisting of an ethylene / α-olefin copolymer of ³ and high-density polyethylene and having a modern carbon ratio of 0 to 8 pMC as defined in ASTM D6866-12 ( Hereinafter, it is characterized in that it may be referred to as “an ethylene resin composition having a modern carbon ratio of 0 to 8 pMC”. The “modern carbon ratio defined in ASTM D6866-12” may hereinafter be simply referred to as “modern carbon ratio”.

  The inner surface layer containing an ethylene-based resin and the outer surface layer containing an ethylene-based resin included in a blow molded multilayer container made of a synthetic resin having a carbon-labeled surface layer of the present invention may have different compositions. May have the same composition.

The synthetic resin blow-molded multilayer container having a carbon-labeled surface layer of the present invention is composed of an ethylene resin composition in which at least one surface layer containing an ethylene resin has a modern carbon ratio of 0 to 8 pMC. It is characterized by being. Therefore, the synthetic resin blow molded multilayer container having the carbon-labeled surface layer of the present invention is:
1) An outer surface layer made of an ethylene-based resin composition having a modern carbon ratio of 0 to 8 pMC and an inner surface layer made of an ethylene-based resin composition having a modern carbon ratio of 0 to 8 pMC, wherein the inner surface layer and the outer surface layer are A synthetic resin blow-molded multilayer container comprising a carbon-labeled surface layer having the same composition;
2) An outer surface layer made of an ethylene resin composition having a modern carbon ratio of 0 to 8 pMC and an inner surface layer made of an ethylene resin composition having a modern carbon ratio of 0 to 8 pMC, wherein the inner surface layer and the outer surface layer are A synthetic resin blow-molded multi-layer container comprising carbon-labeled surface layers having different compositions;
3) A carbon-labeled surface layer comprising an outer surface layer made of an ethylene resin composition having a modern carbon ratio of 0 to 8 pMC and an inner surface layer not made of an ethylene resin composition having a modern carbon ratio of 0 to 8 pMC. Synthetic resin blow molded multilayer container, or
4) A carbon-labeled surface layer comprising an outer surface layer not made of an ethylene resin composition having a modern carbon ratio of 0 to 8 pMC and an inner surface layer made of an ethylene resin composition having a modern carbon ratio of 0 to 8 pMC. One of the synthetic resin blow-molded multilayer containers.

1. Inner Surface Layer Containing Ethylene Resin A synthetic resin blow molded multilayer container including a carbon-labeled surface layer of the present invention is a multilayer container including an inner surface layer containing an ethylene resin. As described above, the inner surface layer of the container of the present invention includes an inner surface layer made of an ethylene resin composition having a modern carbon ratio of 0 to 8 pMC, and an ethylene having a modern carbon ratio of 0 to 8 pMC. In some cases, the inner surface layer is not composed of a resin composition.

  As the ethylene-based resin contained in the inner surface layer, an ethylene-based resin conventionally used for forming the inner surface layer of a synthetic resin blow-molded multilayer container can be used. For example, low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP) and other narrowly defined polyolefins; linear low-density polyethylene (LLDPE), very low-density polyethylene (VLDPE) and other ethylene / α-olefin co-polymers Polymer; Propylene / α-olefin random copolymer such as propylene / ethylene random copolymer; Modified olefin resin (for example, homopolymer or copolymer of olefins and unsaturated carboxylic acid such as maleic acid or fumaric acid, Reactions with acid anhydrides, esters, metal salts, etc.); ionomers (IO); ethylene / vinyl acetate copolymers (EVA); ethylene / methacrylic acid copolymers (EMAA), ethylene / methacrylic acid / unsaturated Aliphatic carboxylic acid copolymer, ethylene / acrylic acid copolymer (EA A), acrylic resins such as ethylene / methyl acrylate copolymer (EMA) and ethylene / ethyl acrylate copolymer (EEA); These resins can be used alone or as a blend with other resins.

Preferred ethylene-based resins include ethylene / α-olefin copolymers such as low density polyethylene (LDPE) and linear low density polyethylene (LLDPE), propylene / α-olefin random copolymers, high density polyethylene (HDPE), A blend of at least two of these, or a blend of at least one of these with another ethylene-based resin can be used. In the synthetic resin blow-molded multilayer container having the carbon-labeled surface layer of the present invention, the inner surface layer containing a particularly preferred ethylene-based resin is low density polyethylene, ethylene having a density of 912 to 935 kg / m ³ as a resin component. -It consists of a resin composition containing at least 1 sort (s) chosen from the group which consists of an alpha olefin copolymer and a high density polyethylene, ie, 1 type, or 2 or more types of these. Here, the low density polyethylene (LDPE) means a low-density polyethylene in a broad sense belonging to so-called soft polyolefin, and other than the conventionally known high-pressure method low-density polyethylene having a density of 910 to 930 kg / m ^3. to, obtained by copolymerizing selectively α- olefins using metallocene catalyst, low density polyethylene having a density of 910~928kg / m ³ ( "metallocene low density polyethylene" low by polymerization using "metallocene catalyst It may be referred to as “density polyethylene”, “metallocene-catalyzed polymerized low density polyethylene”, “M-LDPE”, etc. Hereinafter, it may be simply referred to as “metallocene low density polyethylene”). The metallocene low density polyethylene is known to have long chain branching and excellent moldability, and is a linear low density polyethylene (LLDPE) defined in JIS K6899-1: 2006 in that it has long chain branching. It is sometimes referred to as “linear low density polyethylene” and is a polymer having short chain branches.) And the like, and is distinguished from an ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ . Among them, as an inner surface layer containing a preferable ethylene-based resin, an ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ such as low density polyethylene (LDPE) or linear low density polyethylene (LLDPE), and high A blend with high density polyethylene (HDPE) or a blend with this blend and other ethylene-based resins can be used.

In the synthetic resin blow-molded multilayer container provided with the carbon-labeled surface layer of the present invention, the inner surface layer is an ethylene-based resin composition having a modern carbon ratio of 0 to 8 pMC, that is, as a resin component, low-density polyethylene, density 912 It contains at least one selected from the group consisting of an ethylene / α-olefin copolymer of ˜935 kg / m ³ and a high density polyethylene, and the modern carbon ratio defined in ASTM D6866-12 is 0 to 8 pMC. The case where it consists of a resin composition is demonstrated in detail below.

[Low density polyethylene]
The low-density polyethylene which can be contained in the resin component of the ethylene-based resin composition having a modern carbon ratio of 0 to 8 pMC forming the inner surface layer in the synthetic resin blow molded multilayer container having the carbon-labeled surface layer of the present invention (LDPE) is a high-pressure method low-density polyethylene (generally having a density of 910 to 930 kg / m ³ , preferably 912 to 930 kg / m ³ ) or metallocene low-density polyethylene (JIS K6899-1: 2006). It is preferable to contain at least one kind of LLDPE that is defined and generally has a density of 910 to 928 kg / m ³ , preferably 912 to 928 kg / m ³ . In addition, the density of polyethylene is measured according to JIS K6922-2 (hereinafter the same).

The metallocene low-density polyethylene that can be preferably contained, that is, the low-density polyethylene having a density of 910 to 928 kg / m ³ obtained by selectively copolymerizing an α-olefin using a metallocene catalyst is mainly composed of ethylene. And an ethylene-based polyolefin obtained by polymerizing a mixed monomer having an α-olefin as a subcomponent in the presence of a metallocene catalyst. As the α-olefin, those having 3 to 10 carbon atoms are preferable, and propylene, butene-1, pentene-1, hexene-1, 4-methylpentene-1, heptene-1, octene-1, and the like are preferable. Can be mentioned. These α-olefins are preferably present in the copolymer in an amount of 3 to 15 mol%. The polymerization method of ethylene and α-olefin using a metallocene catalyst is known per se and is synthesized by polymerization in an organic solvent, a liquid monomer or a gas phase method in the presence of a metallocene catalyst. This method can also be used for the purpose of the present invention.

The metallocene catalyst generally includes a metallocene, that is, a transition metal component composed of a complex composed of two substituted or unsubstituted cyclopentadienyl rings and various transition metals, an organoaluminum component, particularly an aluminoxane, and the like. Is a general term for a catalyst consisting of Examples of the transition metal component include metals of groups IVb, Vb or VIb of the periodic table, particularly zirconium or hafnium. The transition metal component in the catalyst is generally represented by the following formula (Cp) ₂ MR ₂
(Wherein Cp is a substituted or unsubstituted cyclopentadienyl ring, M is a transition metal, and R is a halogen atom or an alkyl group) is generally used. . The aluminoxane is obtained by reacting an organoaluminum compound with water, and includes a linear aluminoxane and a cyclic aluminoxane. These aluminoxanes can be used alone or in combination with other organic aluminum.

  As the metallocene catalyst, preferably, a bridged azulene-type metallocene catalyst is used in which the above-mentioned Cp is a substituted cyclopentadienyl ring, and two azulene skeletons condensed to the cyclopentadienyl ring are crosslinked and condensed. can do. In the bridged azulene-type metallocene catalyst, a clay mineral can also be used as a promoter.

  It can be confirmed by the following method that the synthetic resin blow-molded multilayer container having the carbon-labeled surface layer of the present invention contains metallocene low-density polyethylene. That is, a synthetic resin pellet is cut into a glass having a thickness of 100 μm to form a sample, which is laid on a scanning electron microscope SEM and measured with an analyzer that distributes the generated fluorescent X-rays, and Zr (zirconium) or Hf ( The presence of a peak corresponding to the energy of hafnium) is confirmed. The synthetic resin pellets may be scraped from the surface layer of the synthetic resin blow-molded multilayer container, or may be a surface layer obtained by peeling the layers of the synthetic resin blow-molded multilayer container.

  The low density polyethylene has an MFR (temperature 190 ° C., load 2.12 N), preferably 0.01 to 30 g / 10 min, more preferably 0.1 to 5 g / 10 min, and still more preferably 0.2 to 1 g / min. Those within 10 minutes can be used. The low-density polyethylene has a polydispersity (Mw / Mn) that is an index of molecular weight distribution, preferably 1.5 to 9, more preferably 1.9 to 8, and still more preferably 2.3 to 7. In this case, the improvement in moldability is effective. If the polydispersity (Mw / Mn) is less than 1.5, moldability may be difficult, and if it exceeds 9, the surface of the molded product (synthetic resin blow-molded multilayer container) may become sticky. is there. The MFR of the low density polyethylene is measured according to JIS K6922-2, and the polydispersity (Mw / Mn) is measured according to JIS K7252 (the same applies hereinafter).

  As the low-density polyethylene, it is preferable to use a high-pressure method low-density polyethylene using a so-called Ziegler-Natta catalyst or a metallocene low-density polyethylene using a metallocene catalyst, and a synthetic product may be used, but a commercially available product is used. May be. In order to make the inner surface layer an ethylene resin composition having a modern carbon ratio of 0 to 8 pMC, a commercial product of low-density polyethylene derived from fossil fuel, for example, brand name EG0921 manufactured by Braschem Co., Ltd. or manufactured by Nippon Polyethylene Co., Ltd. Kernel (registered trademark), Sumikasen (registered trademark) EP manufactured by Sumitomo Chemical Co., Ltd., and the like can be used.

[Ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ ]
In the synthetic resin blow molded multilayer container having the carbon-labeled surface layer of the present invention, the density 912 can be contained in the resin component of the ethylene-based resin composition having a modern carbon ratio of 0 to 8 pMC forming the inner surface layer. The ethylene / α-olefin copolymer of 935 kg / m ³ is an ethylene-based resin that is a copolymer of ethylene and an α-olefin other than ethylene, and has a density of 912 to 935 kg / m ³ , preferably 914 to It is 933 kg / m < ³ >, More preferably, it is 915-931 kg / m < ³ >. If the density is less than 912 kg / m ³ , sufficient strength may not be obtained. On the other hand, if the density exceeds 935 kg / m ³ , the transparency that may be desired for the container may be insufficient.

The α-olefin other than ethylene forming the ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ is usually an α-olefin having 3 to 10 carbon atoms, preferably 3 to 8 carbon atoms. Examples include propylene, butene-1, pentene-1, hexene-1, heptene-1, octene-1, and 4-methylpentene-1. The content of α-olefin in the ethylene / α-olefin copolymer is 0.05 to 4 mol%, preferably 0.1 to 3.5 mol%, more preferably 0.2 to 3 mol%, The amount is preferably 0.4 to 2.8 mol%, particularly preferably 0.8 to 2.5 mol%. As the ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ^3, a linear low density polyethylene defined by JIS K6899-1: 2006 and commonly called LLDPE can be used. The ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ may be any of those polymerized by a metallocene catalyst, a Ziegler-Natta catalyst, a Phillips catalyst, or the like, but uses a Ziegler-Natta catalyst. It is preferable to use an ethylene / α-olefin copolymer.

The ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ has an MFR (temperature 190 ° C., load 2.12 N), preferably 0.01 to 30 g / 10 minutes, more preferably 0.1 to 5 g. / 10 minutes, more preferably 0.2 to 3 g / 10 minutes. The ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ preferably has a polydispersity (Mw / Mn) as an index of molecular weight distribution, preferably 1.5 to 9, more preferably 2 to 8. More preferably, those in the range of 2.5 to 7 are effective in terms of improving moldability. If the polydispersity (Mw / Mn) is less than 1.5, moldability may be difficult, and if it exceeds 9, the surface of the molded article may become sticky.

As the ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ , a synthetic product may be used, but a commercially available product may be used. In order to make the inner surface layer an ethylene resin composition having a modern carbon ratio of 0 to 8 pMC, for example, a commercially available ethylene / α-olefin copolymer derived from fossil fuel and having a density of 912 to 935 kg / m ³ For example, ULTRAZEX (registered trademark) manufactured by Prime Polymer Co., Ltd., C6 series LLDPE brand name TUF2022 manufactured by Nihon Unicar Co., Ltd., LLDPE brand name PE LH-118 manufactured by Braschem Co., Ltd. can be used.

[High-density polyethylene]
High density polyethylene which can be contained in a resin component of an ethylene-based resin composition having a modern carbon ratio of 0 to 8 pMC forming an inner surface layer in a synthetic resin blow molded multilayer container having a carbon-labeled surface layer of the present invention Means high-density polyethylene commonly referred to as HDPE, and is generally polyethylene having a density of 942-980 kg / m ³ , preferably 943-970 kg / m ³ , more preferably 945-965 kg / m ³ . .

  The high density polyethylene has an MFR (temperature 190 ° C., load 2.12 N) of 0.01 to 30 g / 10 minutes, more preferably 0.1 to 5 g / 10 minutes, still more preferably 0.2 to 1 g / 10 minutes. Those within the range can be used. The polydispersity (Mw / Mn), which is an index of molecular weight distribution, is preferably in the range of 4 to 10, more preferably 5 to 9.5, and even more preferably 6 to 9 to improve the moldability. Effective in terms. If the polydispersity (Mw / Mn) is less than 4, moldability may be difficult, and if it exceeds 10, the surface of the synthetic resin blow molded multilayer container may become sticky.

  As the high-density polyethylene, a homopolymer of ethylene or a copolymer of ethylene and an α-olefin other than ethylene can be used. Examples of α-olefins other than ethylene include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and the like. You may use the above together. When the high density polyethylene is a copolymer of ethylene, the content of the α-olefin in the copolymer is 0.2 to 3 mol%, preferably 0.3 to 2.5 mol%. is there. A copolymer having an α-olefin content exceeding 3 mol% may deteriorate the mechanical properties.

  High-density polyethylene can be obtained by polymerization using a Ziegler-Natta catalyst, a Phillips catalyst, a metallocene catalyst, or the like. High-density polyethylene may be produced by either low-pressure polymerization method or medium-pressure polymerization method. Gas phase polymerization (used widely for polymerization using Ziegler-Natta catalyst), slurry polymerization (used for polymerization using Philips catalyst) Can be obtained by bulk polymerization, solution polymerization, etc., and can also be produced by one-stage polymerization, two-stage polymerization, or more multistage polymerization.

  The high density polyethylene is preferably a low pressure polymerization high density polyethylene using a Ziegler-Natta catalyst. Further, according to the slurry polymerization method using a Philips catalyst, the molecular weight distribution can be a single distribution or a plurality of distributions, so that the melt extrusion moldability of high-density polyethylene can be controlled as desired.

  As the high-density polyethylene, a low-pressure polymerization synthetic polymer using a Ziegler-Natta catalyst can be used, but a low-pressure polymerization high-density polyethylene using a Ziegler-Natta catalyst can be selected from commercially available products. It can also be used. Commercially available products of high-density polyethylene derived from fossil fuel include Novatec (registered trademark) HD manufactured by Nippon Polyethylene Co., Ltd., Hi-Zex (registered trademark) manufactured by Prime Polymer Co., Ltd., Ziegler-Natta catalyst polymerization brand for blow molding manufactured by Braschem. There are names such as IE59U3.

[At least one selected from the group consisting of low-density polyethylene, ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ , and high-density polyethylene]
In the synthetic resin blow-molded multilayer container having a carbon-labeled surface layer of the present invention, the inner surface layer is an ethylene-based resin composition having a modern carbon ratio of 0 to 8 pMC, that is, a low-density polyethylene (with a density of high-pressure low density polyethylene 910~930kg / ^{m 3} or a density metallocene low density polyethylene 910~928kg / ^{m 3} is preferred.), ethylene · alpha-olefin copolymer having a density 912~935kg / ^{m 3,} And when it is made of a resin composition containing at least one selected from the group consisting of high density polyethylene and having a modern carbon ratio of 0 to 8 pMC as defined in ASTM D6866-12, it is contained in the inner surface layer. Examples of the resin component to be used include low density polyethylene, ethylene having a density of 912 to 935 kg / m ³ . It may contain any one kind of synthetic resin selected from the group consisting of a lens / α-olefin copolymer and high-density polyethylene, or may contain two or three kinds of synthetic resins selected from the above group. It may be a thing. Therefore, when the total of the resin components contained in the inner surface layer is 100% by mass, the low-density polyethylene, the ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ , or the high-density polyethylene is contained. Each amount ranges from 0 to 100% by mass and can be adjusted within a desired range. The resin component contained in the inner surface layer is a combination of two or three selected from the group consisting of low-density polyethylene, ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ , and high-density polyethylene. When the resin is contained, each content is preferably in the range of 5 to 95% by mass, more preferably in the range of 10 to 90% by mass, and still more preferably in the range of 15 to 85% by mass. The effect by containing the above synthetic resin is often exhibited. For example, from the viewpoint of improving the handling property by adjusting the melt viscosity of the resin, and improving the slipperiness and rigidity of the surface layer (specifically, the inner surface layer) of the synthetic resin blow molded multilayer container to be formed in a balanced manner. Low-density polyethylene or ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ is 95 to 15% by mass, preferably 93 to 18% by mass, more preferably 90 to 20% by mass, and high-density polyethylene 5 to 5%. It may contain 85 mass%, preferably 7-82 mass%, more preferably 10-80 mass%.

[Modern carbon ratio of resin composition containing at least one selected from the group consisting of low density polyethylene, ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ and high density polyethylene]
In the synthetic resin blow-molded multilayer container having a carbon-labeled surface layer of the present invention, at least one surface layer (here, an inner surface layer is assumed) is a resin composition having a modern carbon ratio of 0 to 8 pMC. Consists of. As is well known, the resin composition may be composed of only the above-described resins (single type or a blend of two or more types) contained as a resin component, or as desired or necessary as described later. Depending on the above, other resins and additives may be contained, and both of them are meant. In the synthetic resin blow-molded multilayer container having the carbon-labeled surface layer of the present invention, as long as the inner surface layer is an ethylene-based resin composition having a modern carbon ratio of 0 to 8 pMC, low density polyethylene, density of 912 to 935 kg The modern carbon ratio of the ethylene / α-olefin copolymer of / m ³ or high density polyethylene is not particularly limited. For example, low-density polyethylene, ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ , or synthetic resin (ethylene-based resin) of high-density polyethylene may be a synthetic resin derived from fossil fuel (usually modern The carbon ratio is in the range of 0 to 8 pMC, and in many cases, the modern carbon ratio is substantially 0 pMC.), Or a plant-derived synthetic resin mixed in a trace amount during the separately collected process It is not excluded that the product is made of synthetic resin recovered by mixing the main material with synthetic resin derived from fossil fuel.

  For example, in the process of separate collection, from a resin composition containing 7% by mass of plant-derived low-density polyethylene (for example, biodegradation rate of 95%) in the resin component. In the case of a synthetic resin blow-molded multilayer container having a carbon-labeled surface layer with an inner surface layer, the low-density polyethylene is a low-density polyethylene derived from fossil fuels (with a biogenic rate of 0%, the modern carbon ratio is And low-density polyethylene containing 7% by mass of plant-derived low-density polyethylene (the modern carbon ratio is calculated as 107 pMC × 0.95 = 101.7 pMC) with a biogenic rate of 95%. The modern carbon ratio is determined based on the result calculated as 7.1 pMC (107 pMC × 0.95 × 0.07 = 7.116 pMC). Was. It corresponds to) a range of 0～8PMC.

From the viewpoint of making the modern carbon ratio of the low density polyethylene within the range of 0 to 8 pMC, the content of the plant-derived low density polyethylene having a biogenic rate of 95% is preferably 5% by mass [modern carbon. The ratio corresponds to 5.1 pMC (determined based on the result calculated as 107 pMC × 0.95 × 0.05 = 5.083 pMC). ], More preferably 1% by mass [modern carbon ratio is 1.0 pMC (determined based on the result calculated as 107 pMC × 0.95 × 0.01 = 1.018 pMC). ] Is desirable. Most preferably, the low-density polyethylene does not contain plant-derived low-density polyethylene and is 100% by mass of low-density polyethylene derived from fossil fuel (corresponding to 0% Corg.renew). The same applies to ethylene / α-olefin copolymers having a density of 912 to 935 kg / m ³ and high density polyethylene.

Furthermore, a modern carbon ratio of 0 to 1 is selected from the group consisting of low density polyethylene, ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ , and high density polyethylene. It is assumed that the range is 8 pMC, the other one or two synthetic resins are those having a modern carbon ratio outside the range of 0-8 pMC, and the inner surface layer is an ethylene resin composition having a modern carbon ratio of 0-8 pMC. There may be. In addition, all of the synthetic resins that are at least one selected from the group consisting of low density polyethylene, ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ , and high density polyethylene have a modern carbon ratio of 0. It is good also as a thing of the range of -8pMC. Generally, low-density polyethylene derived from fossil fuels with a modern carbon ratio of substantially 0 pMC, ethylene / α-olefin copolymers having a density of 912 to 935 kg / m ³ , or high-density polyethylene are readily available and supplied. Stable and inexpensive.

[Other resins]
In the synthetic resin blow-molded multilayer container having the carbon-labeled surface layer of the present invention, when the inner surface layer is formed from an ethylene-based resin composition having a modern carbon ratio of 0 to 8 pMC, the inner surface layer is a resin. As a component, it contains at least one selected from the group consisting of low density polyethylene, an ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ , and a high density polyethylene. Can be contained. Other resins include propylene homopolymers or propylene random copolymers obtained using Ziegler-Natta catalysts, propylene homopolymers, propylene random copolymers or block copolymers obtained using metallocene catalysts. And resin components such as ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / methyl acrylate copolymer, and maleic anhydride-modified polyolefin. The content of these other resins is usually 20% by mass or less, preferably 10% by mass when the total mass of the resin components contained in the ethylene resin composition having a modern carbon ratio of 0 to 8 pMC is 100% by mass. % Or less, more preferably 5% by mass or less. As other resins, it is usually preferable to use a resin derived from fossil fuel, which is easily available and stable in supply. As already explained, as long as the modern carbon ratio of the resin composition forming the inner surface layer can be in the range of 0 to 8 pMC, a resin having a modern carbon ratio exceeding 8 pMC can be used. A resin derived from fossil fuel (modern carbon ratio is substantially 0 pMC) is 100% by mass.

〔Additive〕
The ethylene resin contained in the inner surface layer of the synthetic resin blow-molded multilayer container having the carbon-labeled surface layer of the present invention has improved molding processability and various characteristics of the synthetic resin blow-molded multilayer container. In order to improve the inner surface layer, various additives that are usually used can be contained as required within the range in which the inner surface layer can be formed from an ethylene-based resin composition having a modern carbon ratio of 0 to 8 pMC. As the additive, either an organic substance (which may be a polymer) or an inorganic substance can be used, and a lubricant, stabilizer, antioxidant, surfactant, antistatic agent, antifogging agent, filler (filling) Agent), pigments, and the like, and an optimal combination is selected according to the application. The content in the case of containing these additives may be determined in accordance with the type and purpose of the additive, but is usually 10% by mass or less, preferably 5% by mass or less, more preferably 2% by mass. In order to contribute to “visualization” of the CO ₂ emission amount in particular, the additive content may be desired to be 5000 ppm or less, preferably 2000 ppm or less.

[Lubricant]
The synthetic resin blow-molded multilayer container having a carbon-labeled surface layer according to the present invention is provided with an inner surface layer for improving slipperiness with viscous contents such as mayonnaise, ketchup and sauce filled therein. However, it is preferable to contain a lubricant. As a result, the slipperiness of the inner surface of the container is improved, so that the contents can be filled smoothly, and effects such as excellent liquid drainage of the contents can be obtained when used by consumers. As the lubricant, either an organic lubricant or an inorganic lubricant can be used, but an organic lubricant is preferable, and an unsaturated fatty acid amide or a saturated fatty acid amide that is an organic lubricant is more preferable. That is, the inner surface layer containing the ethylene-based resin of the annular bulge is made of a synthetic resin formed from a composition of an ethylene-based resin containing an unsaturated fatty acid amide, a saturated fatty acid amide or a mixture thereof as an organic lubricant. Blow molded multilayer containers are more preferred. These lubricants may be used as a mixture of two or more. For example, an unsaturated fatty acid amide and a saturated fatty acid amide may be used in combination. Examples of the unsaturated fatty acid amide include 6-tetradecenoic acid amide, oleic acid amide, 8-octadecenoic acid amide, erucic acid amide, arachidonic acid amide, and the like, preferably oleic acid amide or erucic acid amide. Saturated fatty acid amides include butyric acid amide, valeric acid amide, caproic acid amide, caprylic acid amide, capric acid amide, lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, arachidic acid amide, behenic acid amide (behenine Acid amide) and the like, and stearic acid amide or behenic acid amide is preferable. When the inner surface layer containing an ethylene-based resin contains a lubricant, more preferably an organic lubricant, the content thereof is usually 100 to 5000 ppm, preferably 150 to 4500 ppm, based on the resin component containing the ethylene-based resin. Preferably it is 200-4000 ppm. In addition, the content ratio of the saturated fatty acid amide in the case of containing the unsaturated fatty acid amide and the saturated fatty acid amide as the organic lubricant is usually relative to the total amount of the fatty acid amide having the unsaturated carbon double bond and the saturated fatty acid amide. 10% by mass or less, in many cases 8% by mass or less, and in most cases 6% by mass or less.

  In the synthetic resin blow-molded multilayer container having the carbon-labeled surface layer of the present invention, the inner surface layer further preferably contains a fatty acid amide having an unsaturated cis structure carbon double bond as an organic lubricant. The fatty acid amide having an unsaturated cis structure carbon double bond is an unsaturated fatty acid amide having an unsaturated carbon double bond that is an unsaturated cis structure of at least one bond in the molecular structure of the fatty acid amide. When the unsaturated fatty acid amide having a plurality of unsaturated carbon double bonds in the molecular structure of the fatty acid amide, all of the carbon double bonds are unsaturated carbonic bonds having an unsaturated cis structure Amide.

Particularly preferably, the fatty acid amide having an unsaturated cis structure carbon double bond is the following (a ₁ ), (a ₂ ) and (a ₃ ):
_{(A 1) H 2 N-} CO - (- CH 2 -) n -CH = CH - (- CH 2 -) n -CH 3 ( where, n is in the range of 6 ≦ n ≦ 10 integer);
_{(A 2) H 2 N-} CO - (- CH 2 -) m-2 -CH = CH - (- CH 2 -) m -CH 3 ( however, m is an integer in the range of 6 ≦ m ≦ 10) And (a ₃ ) H ₂ N—CO — (— CH ₂ —) _{k + 4} —CH═CH — (— CH ₂ —) _k —CH ₃ (where k is in the range of 6 ≦ k ≦ 10); integer);
At least one fatty acid amide compound represented by a formula selected from the group consisting of:

Fatty acid amide having an unsaturated cis-structured carbon double bond [hereinafter sometimes referred to as “cis-unsaturated fatty acid amide”. The], specifically, for example, cis-9,10-octadecenoamide [oleic acid amide represented by the formula _{(a 1): H 2 N} -CO - (- CH 2 -) 7 -CH = CH- (—CH ₂ —) ₇ —CH ₃ ] (corresponding to n = 7), cis-6,7-tetradecenoamide represented by formula (a ₂ ) [H ₂ N—CO — (— CH ₂ —) ₄ — CH = CH — (— CH ₂ —) ₆ —CH ₃ ] (corresponding to m = 6) and cis-8,9-octadecenoamide [H ₂ N—CO — (— CH ₂ —) ₆ —CH═CH— ( —CH ₂ —) ₈ —CH ₃ ] (corresponding to m = 8), cis-13,14-docosenoamide represented by the formula (a ₃ ) [erucic acid amide: H ₂ N—CO — (— CH ₂ — _{) 11 -CH = CH - (-} CH 2 -) 7 corresponds to -CH _3] (k = 7), and the like.

As the cis unsaturated fatty acid amide, a compound having 2 to 4 carbon double bonds having an unsaturated cis structure in the molecular structure can be used. For example, cis-5,6-8,9-11,12-14,15-arachidonic acid amide [Arachidonic acid amide: H ₂ N-, which has four unsaturated cis-structured carbon double bonds in the molecular structure. _{CO - (- CH 2 -)} 3 -CH = CH-CH 2 -CH = CH-CH 2 -CH = CH-CH 2 -CH = CH - (- CH 2 -) 4 -CH 3 ] and the like.

  The unsaturated fatty acid amide having an unsaturated carbon double bond having a trans structure (fatty acid amide having an unsaturated trans structure carbon double bond) may be insufficiently uniformly blended with an ethylene-based resin, or the trans structure The unsaturated fatty acid amide having a carbon double bond may bleed on the surface of the blow-molded multilayer container or the slipperiness may be deteriorated, and may not function as an organic lubricant.

2. Barrier layer The synthetic resin blow-molded multilayer container having a carbon-labeled surface layer of the present invention has a barrier property against gas barrier properties such as oxygen barrier properties and carbon dioxide gas barrier properties, and barrier properties against water or water vapor. This is a blow molded multilayer container made of synthetic resin, and can improve the storage stability of the contents filled in the multilayer container.

  Examples of the resin forming the barrier layer include partially saponified products of ethylene / vinyl alcohol copolymer or ethylene / vinyl acetate copolymer (hereinafter sometimes collectively referred to as “EVOH”), polyglycolic acid, Glycolic acid / lactic acid copolymer, aromatic polyamide (MXD6) formed from metaxylylenediamine and adipic acid, polyvinylidene chloride, and the like can be used, and EVOH is preferable. The synthetic resin blow-molded multilayer container provided with the carbon-labeled surface layer of the present invention may normally comprise one barrier layer, but may comprise two or more barrier layers.

  As EVOH preferably used as a barrier layer, an ethylene / vinyl acetate copolymer having an ethylene content of 20 to 60 mol%, preferably 25 to 55 mol%, more preferably 30 to 50 mol% is saponified. A saponified copolymer obtained by saponification is used so that the degree is 90 mol% or more, preferably 95 mol% or more, more preferably 97 mol% or more, particularly preferably 99 mol% or more. This EVOH has a molecular weight sufficient to form a film, and generally has an MFR (temperature 190 ° C., load 21.18 N) of 6 g / 10 min or less, preferably 5 g / 10 min or less, more preferably 4 g. / 10 minutes or less. The MFR is measured according to JIS K7210.

3. Outer surface layer containing an ethylene-based resin The synthetic resin blow-molded multilayer container having a carbon-labeled surface layer of the present invention contains an ethylene-based resin in addition to an inner surface layer and a barrier layer containing an ethylene-based resin. It is a multilayer container provided with the outer surface layer which carries out in this order from the container inner side. As described above, the outer surface layer of the container of the present invention includes an outer surface layer made of an ethylene-based resin composition having a modern carbon ratio of 0 to 8 pMC and an ethylene having a modern carbon ratio of 0 to 8 pMC. In some cases, the outer surface layer is not made of a resin composition.

As the ethylene resin contained in the outer surface layer, the same resin as the ethylene resin contained in the inner surface layer can be used. Therefore, the most preferable outer surface layer containing an ethylene-based resin is selected from the group consisting of low-density polyethylene, an ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ , and a high-density polyethylene as a resin component. And a resin composition having a modern carbon ratio of 0 to 8 pMC as defined in ASTM D6866-12. In addition, the ethylene-based resin contained in the outer surface layer may include other resins as desired in order to improve molding processability and various properties of the synthetic resin blow-molded multilayer container as in the case of the inner surface layer. A resin can be contained, and a lubricant or other various additives that are generally used can be contained as necessary. The content in the case of containing these additives may be determined in accordance with the type and purpose of the additive. In particular, when the outer surface layer contains a lubricant such as an unsaturated fatty acid amide, the outer surface layer may be damaged by contact with adjacent containers or devices during manufacture of a blow molded multilayer container, transportation or filling of contents. The effect of preventing generation of non-defective products, production line stop, equipment failure, etc., and holding the gripper inserted to hold the multilayer container stably and reliably. In addition, the surface gloss may be excellent.

The outer surface layer is an ethylene resin composition having a modern carbon ratio of 0 to 8 pMC, that is, as a resin component, a low density polyethylene, an ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ , and a high density A resin containing at least one selected from the group consisting of polyethylene and a resin composition having a modern carbon ratio of 0 to 8 pMC as defined in ASTM D6866-12. The components and additives are the same as those described for the inner surface layer.

4). Recovery layer The synthetic resin blow-molded multilayer container having a carbon-labeled surface layer of the present invention includes at least an inner surface layer containing an ethylene-based resin, a barrier layer, and an outer surface layer containing an ethylene-based resin from the inside of the container. A synthetic resin blow-molded multi-layer container having a carbon-labeled surface layer with a recovery layer is also preferred. By including the recovery layer, the strength of the synthetic resin blow-molded multilayer container including the carbon-labeled surface layer can be increased, and the resource recyclability can be increased. The recovery layer is a material recovered from the synthetic resin blow-molded multilayer container itself provided with the carbon-labeled surface layer of the present invention (such as burrs, unnecessary parts of product containers, recovered products of containers outside the product standards), or This is a layer containing, as a main component, a material recovered in the step of producing a synthetic resin blow-molded multilayer container having a carbon-labeled surface layer of the present invention. In particular, the synthetic resin blow-molded multilayer container having a carbon-labeled surface layer of the present invention is formed by introducing blow air into a cylindrical molten parison to form a container-shaped blow molded article ( Hereinafter, it may be necessary to excise the “bag portion”), but the excised bag portion can be made into a recovery layer using a recovered resin powdered by a crusher as a raw material. In addition, resin collected by excising parts other than the bag part of the container-shaped blow molded product, a parison before blow molding, and materials and raw materials for forming each layer of a synthetic resin blow molded multilayer container, etc. May be contained as a main component.

  The recovery layer further contains raw materials for forming each layer of the synthetic resin blow molded multilayer container provided with the carbon-labeled surface layer of the present invention, for example, various resin raw materials, compounding agents, adhesives, and the like. Also good. Although not essential in the present invention, the recovery layer preferably has a modern carbon ratio of 0 to 8 pMC.

5. Adhesive layer The synthetic resin blow-molded multilayer container having the carbon-labeled surface layer of the present invention can further have an adhesive layer interposed between the layers in order to increase the delamination strength of each layer constituting the multilayer container. . Synthetic resin blow molded multilayer containers may not require an adhesive layer from the viewpoint of heat resistance and molding processability, but mechanical properties, impact resistance, delamination resistance, etc. are required. In some applications, an adhesive layer is preferably interposed. Specifically, a synthetic resin blow molded multilayer container having an adhesive layer between one or both of the inner surface layer and the barrier layer, or between the barrier layer and the outer surface layer is preferable. Furthermore, when the synthetic resin blow-molded multilayer container provided with the carbon-labeled surface layer of the present invention is provided with a recovery layer, or is provided with two or more barrier layers, any of these layers is used. An adhesive layer may be provided so as to be adjacent to each other.

The adhesive resin contained in the adhesive layer is preferably a resin that can be extruded and has good adhesiveness to each layer. For example, ethylene / polar comonomer copolymer, acid-modified polyolefin , Glycidyl group-containing ethylene copolymer, thermoplastic polyurethane, polyamide / ionomer, polyacrylimide and the like, and ethylene / polar comonomer copolymer or acid-modified polyolefin is preferable. Examples of the ethylene / polar comonomer copolymer include an ethylene / vinyl acetate copolymer, an ethylene / carbon alkyl acrylate copolymer, an ethylene / acrylic acid copolymer, an ethylene / methacrylic acid copolymer, And ethylene / methacrylic acid / unsaturated carboxylic acid copolymer. Examples of the acid-modified polyolefin include a reaction product of an olefin homo- or copolymer and an unsaturated carboxylic acid such as maleic acid or fumaric acid, or an acid anhydride, ester or metal salt thereof. Include maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, and the like. Although the melting temperature of adhesive resin can be selected suitably, Preferably it is 70-130 degreeC, More preferably, it is 80-120 degreeC. The density of the adhesive resin is preferably 880 to 960 kg / m ³ , and more preferably 900 to 940 kg / m ³ . Moreover, it is preferable that MFR (temperature 190 degreeC, load 21.18N) of adhesive resin is 0.5-20 g / 10min, More preferably, it is 1.0-15g / 10min. The MFR is measured according to JIS K7210. The adhesive resins contained in the adhesive layer may be used alone or in combination of two or more. Further, the adhesive resin contained in the adhesive layer may contain various additives such as a heat stabilizer, a plasticizer, an antioxidant, a light stabilizer, a lubricant, and a dye as desired. Although the thickness of an adhesive layer is not specifically limited, Usually, it is 0.5-10 micrometers, and is 1-5 micrometers in many cases.

6). Layer structure of a synthetic resin blow molded multilayer container provided with a carbon labeled surface layer A synthetic resin blow molded multilayer container provided with a carbon labeled surface layer of the present invention includes at least an inner surface layer containing an ethylene-based resin, It is a multilayer container provided with an outer surface layer containing a barrier layer and an ethylene-based resin in this order from the inside of the container. Preferably, it is a synthetic resin blow-molded multilayer container further provided with a recovery layer, and further is a synthetic resin blow-molded multilayer container further provided with an adhesive layer. Specific examples of the layer structure include, for example, an inner surface layer / recovery layer / barrier layer / outer surface layer layer structure, an inner surface layer / adhesive layer / barrier layer / outer surface layer layer structure, and an inner surface layer / barrier layer. / Adhesive layer / layer structure of outer surface layer, inner surface layer / adhesive layer / barrier layer / adhesive layer / outer surface layer, inner surface layer / recovery layer / adhesive layer / barrier layer / adhesive layer / outer surface layer And a synthetic resin blow molded multilayer container having a layer structure of inner surface layer / recovery layer / barrier layer / adhesive layer / barrier layer / outer surface layer. Therefore, to illustrate a more specific layer structure of a synthetic resin blow molded multilayer container having a carbon-labeled surface layer of the present invention,
Inner surface layer / barrier layer / outer surface layer,
Inner surface layer / recovery layer / barrier layer / outer surface layer,
Inner surface layer / adhesive layer / barrier layer / outer surface layer,
Inner surface layer / barrier layer / adhesive layer / outer surface layer,
Inner surface layer / adhesive layer / barrier layer / adhesive layer / outer surface layer,
Inner surface layer / recovery layer / adhesive layer / barrier layer / adhesive layer / outer surface layer,
Inner surface layer / recovery layer / barrier layer / adhesive layer / barrier layer / outer surface layer,
Inner surface layer / recovery layer / adhesive layer / barrier layer / adhesive layer / recovery layer / outer surface layer,
Inner surface layer / adhesive layer / barrier layer / barrier layer / adhesive layer / outer surface layer,
Inner surface layer / adhesive layer / barrier layer / adhesive layer / barrier layer / adhesive layer / outer surface layer,
Inner surface layer / recovery layer / adhesive layer / barrier layer / barrier layer / adhesive layer / outer surface layer,
Inner surface layer / recovery layer / adhesive layer / barrier layer / adhesive layer / barrier layer / adhesive layer / outer surface layer,
Inner surface layer / recovery layer / adhesive layer / barrier layer / barrier layer / adhesive layer / recovery layer / outer surface layer, and
Examples of the layer structure include, but are not limited to, inner surface layer / recovery layer / adhesive layer / barrier layer / adhesive layer / barrier layer / adhesive layer / recovery layer / outer surface layer.

  The thickness of the synthetic resin blow-molded multilayer container having the carbon-labeled surface layer of the present invention is not particularly limited, but the total thickness of the trunk is usually 20 μm to 5 mm, preferably 100 μm to 3 mm, more preferably 200 μm. Within the range of ~ 1 mm. The synthetic resin blow-molded multilayer container provided with the carbon-labeled surface layer of the present invention may have a uniform thickness as a whole, but the thickness may be changed depending on the part. In general, it is preferable to increase the thickness of the bottom of the container.

  The thickness of the surface layer relative to the total thickness (meaning the total thickness of the inner surface layer and the outer surface layer) is usually 60 to 99% (thickness ratio, hereinafter the same) with respect to the total layer thickness. Preferably it is 65 to 98%, more preferably 70 to 97%. The thickness of the barrier layer is usually 1 to 40%, preferably 2 to 8%, more preferably 3 to 6% (thickness ratio). When a recovery layer is provided, the thickness is usually 5 to 30%, preferably 10 to 25%, more preferably 15 to 25%. When the adhesive layer is provided, the total thickness of the adhesive layer is usually 0.005 to 2%, preferably 0.007 to 1.5%, and more preferably 0.008 to 1.2%.

  The ratio of the outer surface layer to the entire surface layer of the surface layer (inner surface layer and outer surface layer) in the synthetic resin blow-molded multilayer container provided with the carbon-labeled surface layer of the present invention is not particularly limited, but is usually 10 to 10. 80%, preferably 15 to 75%, more preferably 20 to 70%, particularly preferably 25 to 65%.

II. A synthetic resin blow-molded multilayer container comprising a mouth, an annular recess, a shoulder, a trunk and a bottom in order along the container axial direction The synthetic resin blow-molded multilayer container having a carbon-labeled surface layer of the present invention A synthetic resin blow-molded multi-layer container comprising a portion, an annular recess, a shoulder, a body portion, and a bottom portion in order along the container axial direction:
i) The layer constitution of the multilayer container comprises at least an inner surface layer containing an ethylene-based resin, a barrier layer and an outer surface layer containing an ethylene-based resin in this order from the inside of the container;
ii) The mouth portion has a male thread region on the outer peripheral surface;
iii) the annular recess is reduced in diameter from the male thread region and then expanded to connect to the shoulder;
iv) The shoulder includes an annular bulge at the upper end;
v) The annular bulge is formed by bending the inner surface of the inner surface layer toward the outside of the container along the container axial direction, and then bending toward the inside of the container. And having a thickness of 20-55% of the thickness of the mouth; and
vi) At least one surface layer containing an ethylene-based resin is selected from the group consisting of low-density polyethylene, an ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ , and a high-density polyethylene as a resin component. Comprising a resin composition having a modern carbon ratio of 0 to 8 pMC as defined in ASTM D6866-12;
A blow molded multilayer container made of a synthetic resin having a carbon-labeled surface layer. That is, the synthetic resin blow-molded multilayer container having a carbon-labeled surface layer of the present invention is a multilayer container having a mouth, an annular recess, a shoulder, a trunk, and a bottom sequentially along the container axial direction. When the container is in an upright posture, the bottom, the abutment, the shoulder, the trunk, and the bottom are sequentially provided from the top to the bottom, so that the bottom abuts against the grounding surface and can stand upright. It is a container. The synthetic resin blow-molded multilayer container having a carbon-labeled surface layer according to the present invention has an annular bulge in which the shoulder connected to the annular recess has a specific inner surface shape and thickness at the upper end, as will be described in detail later. It has the feature in the point provided with a part. Volume of blow-molded multilayer container of the present invention is not particularly limited, is preferably in the range of 100～3000Cm ^3, more preferably 200～2000Cm ^3, more preferably 300~1000cm ^3.

  Hereinafter, the synthetic resin blow-molded multilayer container having the carbon-labeled surface layer of the present invention will be further described with reference to the drawings. In addition, drawing is a schematic sectional drawing for helping to understand the aspect of the container of this invention.

1. The mouth portion and the male thread region The synthetic resin blow molded multilayer container having the carbon-labeled surface layer of the present invention includes a mouth portion 1 as shown in FIG. The male thread 121 has a male thread region 12 in which the male thread 121 bulges. Specifically, the mouth portion 1 of the synthetic resin blow-molded multilayer container having the carbon-labeled surface layer of the present invention has an opening at the upper end along the container axis (not shown), that is, at the uppermost end of the mouth portion 1. 11, a male thread 121 bulges outward from the peripheral surface of the male thread region 12 below the opening 11. The male thread 121 is provided to attach a cap (lid) having a female thread on the inner peripheral surface after filling a blow molded multilayer container made of synthetic resin with the contents and sealing the opening 11. .

  The male thread 121 provided in the mouth portion 1 of the synthetic resin blow-molded multilayer container having a carbon-labeled surface layer may have a single thread structure, but the rotation operation required for detaching the cap (lid) In order to reduce the amount and to reduce the amount of the synthetic resin material necessary for molding the mouth of the synthetic resin blow molded multilayer container, a multi-thread structure such as a double thread structure may be employed. .

  The length of the male thread region 12 in the container axial direction, that is, the length in the vertical direction is usually 50 to 90%, preferably 55 to 80%, more preferably, the length of the mouth portion 1 in the container axial direction. Is in the range of 60-75%. The male thread region 12 is provided so that the cap (lid) can be smoothly mounted, and is provided via a lid mounting guide region provided below the opening 11 as necessary. The mouth portion 1 is formed over substantially the lower end. When providing the lid mounting guidance area, the length is usually in the range of 1 to 50%, preferably 3 to 45%, more preferably 5 to 40% with respect to the length of the mouth portion 1 in the container axial direction. be able to. In a synthetic resin blow-molded multilayer container, a neck ring that functions as a support ring may be provided at the lower end of the mouth of the multilayer container, the inner surface of which is smooth and convex outward. Yes, it is common in synthetic resin blow-molded multilayer containers in which a parison is formed by injection molding, but it is formed by a synthetic resin blow-molded multilayer container having a carbon-labeled surface layer of the present invention, particularly by direct blow molding In the multilayer container to be used, it is not necessary to provide a neck ring.

2. Annular recess The synthetic resin blow-molded multilayer container having a carbon-labeled surface layer according to the present invention is connected to the male thread region 12 of the mouth 1 and is reduced in diameter from the male screw region 12, and then expanded in diameter. An annular recess 2 connected to the shoulder 3 is provided. Since the annular recess 2 is connected to the male thread region 12 of the mouth 1, the cross-sectional shape thereof is an annular shape having a substantially circular outer diameter and inner diameter, and the outer diameter of the male thread region 12 is Since the recess is formed because it is smaller than the outer diameter, it is called an annular recess. The outer diameter of the annular recess 2 is usually in the range of 75 to 100%, preferably 80 to 100%, more preferably 85 to 100% with respect to the outer diameter of the mouth portion 1, and the container axis direction of the annular recess 2 Is usually 15 to 50%, preferably 17 to 40%, more preferably 20 to 35% of the length of the male thread region 12 of the mouth portion 1 in the container axial direction.

  The annular recess 2 is connected to the male thread region 12 with a reduced diameter so that the female thread inside the skirt portion of the cap is closed when the cap is fitted to the male thread region 12 of the mouth portion 1 to close the cap. Forming a space to absorb the peristalsis of the end of the skirt part when it is free to rotate until it comes off from the male thread region 12 of the mouth part 1 of the container and the back of the cap top plate contacts the upper end of the mouth part 1 of the container. Therefore, it is possible to avoid a sudden increase in closing torque when the cap is closed. Note that if the cap is slanted or the cap is closed halfway, the sealing will be poor, and the outside air may enter the container and cause the contents to decay or discolor. Further, the annular recess 2 is enlarged in diameter and connected to the shoulder portion 3 so that when the cap is closed, the upper end of the mouth portion 1 comes into contact with the back of the cap top plate to complete the closing of the cap. Since the position can be regulated by contacting the end with the upper surface of the shoulder 3 of the container, the pressure on the upper end of the mouth 1 does not exceed a predetermined pressure, and deformation of the upper end of the mouth 1 is suppressed. Is done.

3. The shoulder portion and the annular bulge portion The synthetic resin blow-molded multilayer container having the carbon-labeled surface layer of the present invention has a shoulder portion 3 connected to the annular recess 2 and an annular bulge portion 31 at its upper end. It is. The annular bulging portion 31 provided at the upper end of the shoulder portion 3 has an annular shape having a substantially circular outer diameter and inner diameter, and the outer diameter is larger than the outer diameter of the mouth portion 1. Since the bulging part is formed as compared with 1, it is called an annular bulging part. The blow molded multilayer container made of a synthetic resin having a carbon-labeled surface layer according to the present invention includes an annular bulging portion 31 having an inner surface shape and thickness peculiar to the shoulder portion 3. A gripper (not shown) is inserted into the end face to grip the multilayer container, and the posture of the multilayer container can be held in an upright state, and the container can be transported while the multilayer container is in an upright state. Further, since the outer diameter of the annular bulging portion 31 is substantially circular, the gripper can be easily inserted from any direction of the multilayer container. In addition, the shoulder part 3 means the site | part connected from the lower end of the annular recessed part 2 to the trunk | drum 4, being the same diameter or expanding. Further, since the cross-sectional shapes of the mouth portion 1 and the annular recess 2 are generally substantially circular, the shoulder portion 3 connected to the lower end of the annular recess 2 is different from the substantially circular shape in cross-sectional shape. And the area | region which changes to the predetermined | prescribed shape of a bottom part along a container axial direction. Since the shoulder portion 3 may be in constant or frequent contact or sliding contact with a gripper inserted into the lower end surface of the annular bulging portion 31 provided at the upper end thereof, it is preferable that at least the outer surface thereof is excellent in slipperiness.

(Annular bulge)
The diameter of the annular bulging portion 31 and the length in the container axial direction can be determined in consideration of the outer diameter of the annular concave portion 2 and the shoulder portion 3, the size and shape of the gripper, and the like. The diameter of the annular bulging portion 31 is generally 110 to 600%, preferably 130 to 400%, more preferably 150 to 300% with respect to the diameter of the mouth portion 1. The length of the annular bulging portion 31 in the container axial direction is usually 10 to 50%, preferably 12 to 40%, more preferably relative to the length of the male thread region 12 of the mouth portion 1 in the container axial direction. It is in the range of 15 to 30%. By making the diameter of the annular bulging portion 31 and the length in the container axial direction within the above ranges, for the transportation of the blow molded multilayer container made of synthetic resin in the mouth sealing process and other production processes after the molding of the container. A gripper that is inserted into the annular bulging portion 31 and abuts the lower surface of the annular bulging portion 31 to support the synthetic resin blow-molded multilayer container can be stably and securely held. It can be stable and reliable. If the diameter of the annular bulging portion 31 is too small or the length in the container axial direction is too short, the gripper may not be inserted sufficiently or impossible, and the container may not be stably and reliably gripped. In addition, if the diameter of the annular bulging portion 31 is too large or the length in the container axial direction is too long, the container may not be gripped stably and reliably, or the container may not be delivered smoothly. There is.

  The synthetic resin blow-molded multilayer container having a carbon-labeled surface layer according to the present invention has a shoulder portion 3 provided with an annular bulging portion 31 at the upper end thereof, and the annular bulging portion 31 is provided inside the inner surface layer container. The surface is formed by bending toward the outside of the container along the container axial direction, and then bending toward the inside of the container, and is 20 to 55% of the thickness of the mouth portion 1. It has the thickness of this. That is, as shown in FIG. 2, since the outer diameter of the annular bulging portion 31 is larger than the outer diameter of the mouth portion 1, the outer surface of the outer surface layer in the cross section faces the outside of the container. Although it is clear that there is a portion that is bent along the axial direction (that is, a portion that has a large diameter), the annular bulging portion 31 has a surface inside the container of the inner surface layer along the container axial direction. It is formed by bending toward the outside of the container and then bending toward the inside of the container, and is characterized by having a thickness of 20 to 55% with respect to the thickness of the mouth portion 1 . The thickness of the annular bulging portion 31 refers to the thickness near the tip of the annular bulging portion 31. The thickness of the annular bulging portion 31 is preferably 22 to 52%, more preferably 25 to 50%, with respect to the thickness of the mouth portion 1. Here, the thickness of the mouth portion 1 refers to the thickness of the mouth portion 1 in the male thread region 12 in the portion where the male thread 121 is not present in the male thread region 12 of the mouth part 1. Since the mouth portion 1 is hardly affected by stretching and thinning due to the blow pressure, the thickness of the mouth portion 1 is substantially equal to the thickness of the parison before blow molding, and the thickness of the annular recess 2 is also the same. It is almost equivalent.

  An annular bulging portion 31 formed by bending the inner surface of the inner surface layer toward the outer side of the container along the axial direction of the container and then bending toward the inner side of the container This is because the bulging portion 31 is formed by extending the parison by blow molding and accompanying thinning. On the other hand, for example, the flange formed in the parison by injection molding has a substantially flat curved surface inside the container of the inner surface layer, and is usually bent toward the outside of the container along the container axial direction. Then, it does not correspond to the annular bulging portion formed by bending toward the inside of the container.

  The synthetic resin blow-molded multilayer container having a carbon-labeled surface layer according to the present invention includes the annular bulging portion 31 at the upper end of the shoulder portion 3, thereby speeding up the production of the blow-molded container. In various processes after container molding, for example, it is possible to stably and reliably carry out gripping of a synthetic resin blow-molded multilayer container filled with contents by inserting a gripper, and in transporting between processes after container molding The container can maintain a predetermined posture state, which has a remarkable effect that has not been expected in the past. The reason for this is not clear, but the annular bulge 31 provided at the upper end of the shoulder 3 has a specific inner surface shape and thickness, so that the annular bulge 31 has a strong spring function. As a result, it is presumed that the shape restoring force increases in gripping and transporting the container after the container is formed.

  On the other hand, when it is intended to form an annular bulging portion that extends outward from the container by blow molding, the annular bulging portion is generally formed so that the inner surface of the inner surface layer faces outward from the container. Although it is turned and bent along the container axial direction, as a result of the parison in the position corresponding to the annular bulge being extended by the blow pressure so as to be in the shape of the annular bulge, the annular bulge is The region from the root to the apex of the annular bulge is typically thinned to a thickness of less than 20% of the thickness of the mouth. Therefore, the formed annular bulging portion does not correspond to the annular bulging portion 31 in the multilayer container of the present invention shown in FIG. In a multi-layer container having a thin annular bulge portion (having a shape usually formed by blow molding as described above) having a thickness of less than 20% with respect to the thickness of the mouth portion, the annular bulge portion As a result of not being able to expect a strong spring function at the annular bulging portion, the shape restoring force is insufficient in gripping and transporting the container after container forming. On the other hand, when the annular bulging portion has a thickness exceeding 55% with respect to the thickness of the mouth portion, the annular bulging portion is poorly formed (the lower surface of the annular bulging portion is not a perfect plane, As a result, strong spring function cannot be expected and the shape restoring force is insufficient for gripping and transporting the container after container forming. In addition, the weight of the annular bulging portion increases, the gripping by the gripper is not reliable, and the container may fall during the gripping. Further, as shown in FIG. 3, the annular bulging portion has the inner surface of the inner surface of the container bent toward the outside of the container along the container axial direction, and then bent toward the inside of the container. The shape is a thick-walled portion filled with a synthetic resin that hangs substantially flat (that is, a shape whose inner surface is smooth and convex outward. Normal injection molding) )), The strong spring function is not expected to be exhibited. As a result, there is insufficient shape restoring force in gripping and transporting the container after forming the container, and an annular bulge is formed. The weight of the part and the weight of the container increase.

  Furthermore, the inner surface layer containing the ethylene-based resin of the annular bulging portion 31 is made of an unsaturated fatty acid amide, a saturated fatty acid amide or a mixture thereof, which is a lubricant, preferably an organic lubricant, more preferably an unsaturated cis structure carbon double layer. When formed from a composition of an ethylene-based resin containing a fatty acid amide having a bond, the annular bulging portion 31 is formed so that the inner surface of the inner surface layer on the inner side of the container extends along the container axial direction. For example, when the blow-molded multilayer container is a container filled with a viscous content, it has a shape formed by bending toward the inside and then bending toward the inside of the container. This is preferable because the adherence of objects to the inner surface of the multi-layer container is reduced, the discharge becomes smooth, and the liquid breakage is improved. Although not essential in the synthetic resin blow-molded multilayer container having the carbon-labeled surface layer of the present invention, the outer surface layer containing the ethylene-based resin of the annular bulging portion 31 is a lubricant, preferably an organic lubricant. When formed from a composition of an ethylene-based resin containing an unsaturated fatty acid amide, a saturated fatty acid amide or a mixture thereof, more preferably a fatty acid amide having an unsaturated cis structure carbon double bond, As a result of improving the slipperiness of the outer surface of the container of the protruding portion 31, there is an effect that it is possible to stably and surely hold a gripper or the like inserted to hold the blow molded multilayer container.

4). Body and Bottom A synthetic resin blow molded multilayer container having a carbon-labeled surface layer according to the present invention includes a mouth part 1, an annular recess 2, a shoulder part 3, a body part 4 and a bottom part in order along the container axial direction. This is a blow molded multilayer container made of synthetic resin. The body 4 and the bottom can be configured in the same manner as a normal synthetic resin blow-molded multilayer container, and the cross-sectional shape thereof is smoothly connected to the mouth 1 and the annular recess 2 via the shoulder 3. However, as long as it is possible, it is not particularly limited, and can be a circular shape, an elliptical shape, or other general-purpose shapes.

III. Synthetic resin blow-molded multilayer container having a carbon-labeled surface layer A synthetic resin blow-molded multilayer container having a carbon-labeled surface layer of the present invention comprises a mouth, an annular recess, a shoulder, a trunk, A synthetic resin blow-molded multilayer container having a bottom portion sequentially along the container axial direction: i) The multilayer container includes at least an inner surface layer containing an ethylene-based resin, a barrier layer, and an ethylene-based resin. And ii) the mouth portion has a male thread region on the outer peripheral surface; iii) the annular recess has a smaller diameter than the male thread region, and then expands the diameter. Connected to the shoulder; iv) The shoulder is provided with an annular bulge at the upper end; v) The inner surface of the inner surface layer of the annular bulge is outside the container along the container axial direction. Bend towards the side and then towards the inside of the container And having a thickness of 20 to 55% with respect to the thickness of the mouth; and vi) at least one surface layer containing an ethylene-based resin as a resin component, A modern carbon ratio defined in ASTM D6866-12, which contains at least one selected from the group consisting of low-density polyethylene, ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ , and high-density polyethylene The production method is not limited as long as a synthetic resin blow molded multilayer container having a carbon-labeled surface layer can be obtained. Accordingly, as a method for producing a synthetic resin blow-molded multilayer container having a carbon-labeled surface layer of the present invention, a multilayer parison having a predetermined layer structure (hereinafter sometimes referred to as “multilayer parison”) is used. It is only necessary to obtain a multilayer synthetic resin blow-molded multilayer container which is a blow-molded product by blow-molding in a split mold having a cavity wall of a desired container shape. After manufacturing the multi-layer parison, it may be stored at room temperature or room temperature, and it may be a cold parison method in which it is heated to a predetermined temperature when blow molding is performed, or the multi-layer parison is manufactured and continuously blow-molded. The parison method may be used. The multi-layer parison can be produced by injection molding, but a method of producing a cylindrical (hereinafter sometimes referred to as “tubular” or “pipe”) multi-layer parison by melt extrusion is preferable. A direct blow molding method in which the multilayer parison coextruded by the method is subsequently blow molded into a container shape is more preferable. Hereinafter, a method for obtaining a synthetic resin blow molded multilayer container (direct blow molded multilayer container) having a carbon-labeled surface layer formed by direct blow molding will be described.

1. Production of multilayer parison Examples of methods for producing a multilayer parison having a desired layer structure by coextrusion include a coextrusion method using a circular die, a coextrusion method using a T die, and a coextrusion method using inflation molding. However, when manufacturing a so-called bottle-shaped container by blow molding, it is preferable to manufacture a cylindrical (pipe-shaped) multilayer parison by a coextrusion method using an annular die. When manufacturing a multilayer parison by the co-extrusion method using an annular die, use the number of extruders corresponding to the type of resin, and expand the resin corresponding to each layer in an annular shape, while melting the molten resin in the die passage. The layers are merged so as to have a predetermined layer structure. When the inner and outer surface layers, which are the surface layers, are made of the same type of resin, they are further branched via a branch channel so as to sandwich resin raw materials that form other layers, and then merged in an extrusion die. Then, the resin is extruded from the annular die head in a state of being laminated in a desired layer configuration. The temperature of the die head is usually 120 to 240 ° C, preferably 130 to 230 ° C, more preferably 140 to 220 ° C. As the shape of the die orifice, not only a circular shape but also a flat shape can be used. According to the co-extrusion method using an annular die, control adjustment such as a change in the thickness of the multilayer parison can be performed relatively easily.

  As described above, the multilayer parison can also be manufactured by co-injection molding. In this case, by using a molding machine equipped with a plurality of injection cylinders, the melted surface layer (outer surface) is formed from one gate in a single parison injection mold cavity by a single clamping operation. The resin composition forming the layer and / or the inner surface layer) and the resin material forming the other layer are co-injected to form a bottomed multilayer parison. A barrier layer such as an EVOH layer may not be present on part or all of the bottom of the multilayer parison. That is, since the thickness of the bottom portion is generally larger than the thickness of the barrel portion, the barrier property can be exhibited even when the bottom portion is substantially composed of an ethylene resin composition layer. By disposing the barrier layer only on the body portion, it may be easy to prevent the mechanical strength of the multilayer synthetic resin blow-molded multilayer container from being lowered and to control the thickness of the barrier layer uniformly.

2. Blow molding When forming a container-shaped blow molded product from a parison by blow molding, the cylindrical multilayer parison coextruded by the above method is sandwiched between split molds and the lower end is fused as necessary. The upper end is cut off, and then a pressurized gas or the like is blown from the opened upper end to form a container shape. Then, a portion (head or bag) corresponding to the upper part of the mouth of the unnecessary container is formed. By cutting, a blow molded multilayer container made of synthetic resin is obtained. A pinch-off portion is formed as a part of the parting line at the bottom of the container integrally formed by blow molding as a trace of a cylindrical parison sandwiched between split molds and fused at the lower end. When the parison is formed by injection molding, a gate mark is formed at the bottom of the blow molded multilayer container.

As the mold for blow molding, either a mirror-finished one or a sandblasted one can be used, and the surface temperature of the mold is generally preferably in the range of 10 to 50 ° C. Moreover, although air, nitrogen, etc. can be used as a pressurized gas for blow molding, it is preferable to use sterilized air, and the pressure is in the range of 1.0 to 15 kg / cm ^2. Is appropriate.

  The blow molded multilayer container made of synthetic resin having the carbon-labeled surface layer of the present invention can be manufactured by direct blow molding. In the direct blow molding process, the multilayer parison is adjusted to a temperature at which it can expand, and then inserted into a cavity of a blow molding die, and direct blow molding is performed by blowing a pressurized gas or the like. The total expansion ratio in a synthetic resin blow-molded multilayer container produced by direct blow molding is usually about 6 to 9 times. The synthetic resin blow-molded multilayer container having a carbon-labeled surface layer according to the present invention includes an annular bulging portion having a specific inner surface shape and thickness, and is therefore easy to control and adjust the shape. Thus, direct blow molding is preferred.

  The synthetic resin blow-molded multilayer container having the carbon-labeled surface layer of the present invention can be produced by stretch blow molding. In the stretch blow molding process, the multilayer parison is adjusted to a temperature at which it can be stretched, and then inserted into a cavity of a blow mold, and a stretched blow molding is performed by blowing a pressurized gas such as air. In order to perform the stretching in the length direction, a stretching rod may be used. Stretch blow molding can be performed by either a hot parison system or a cold parison system. The total draw ratio is usually about 6 to 9 times.

  When manufacturing a heat-resistant synthetic resin blow-molded multilayer container suitable for hot filling of contents, the temperature of the blow mold is set to 100 to prevent thermal shrinkage and deformation of the container during heat filling. The temperature may be raised to a temperature equal to or higher than ° C., and heat treatment (heat setting) may be performed in the mold. The mold temperature is 100 to 165 ° C., preferably 145 to 155 ° C. for a general heat resistant container, and 160 to 165 ° C. for a high heat resistant container. The heat treatment time varies depending on the thickness of the synthetic resin blow molded multilayer container and the heat treatment temperature, but is usually 1 to 30 seconds, preferably 2 to 20 seconds.

3. Adjustment of the shape of the annular bulging portion The synthetic resin blow-molded multilayer container provided with the carbon-labeled surface layer of the present invention has an annular bulging portion provided at the upper end of the shoulder portion, and the inner surface layer of the inner surface of the container is , Bent toward the outside of the container along the container axial direction, and then bent toward the inside of the container, and has a thickness of 20 to 55% of the thickness of the mouth. It is characterized by having. The specific structure of the annular bulging portion includes the supply rate (discharge rate or extrusion rate) of the molten parison from the annular die to the blow mold, the composition and thickness of the inner surface layer containing the ethylene resin, and in some cases Furthermore, it can be obtained by adjusting the composition and thickness of the outer surface layer containing the ethylene-based resin, blow conditions (pressure of blown gas, blow rate, etc.) and the like. The melt parison supply speed from the annular die to the blow mold can be controlled by a so-called parison controller that stretches a part of the melt parison or controls the speed of the melt parison in the vertical downward direction.

IV. Transport and grip of synthetic resin blow-molded multilayer containers with carbon-labeled surface layers Synthetic resin blow-molded multilayer containers with carbon-labeled surface layers manufactured by direct blow molding, etc. In the contents filling process, the contents such as food are filled in the multilayer container, heated, sterilized and cooled as necessary, and after checking the filling amount, the container is transported to the mouth seal device. In the mouth sealing step, the mouth opening of the container is sealed with a sealing material to form a sealed container. Next, the sealed containers are conveyed to the cap mounting device (capper) while being aligned, and the cap is wound around the mouth of the sealed container by the cap mounting device in the cap mounting process.

  The conveyance of the container after the container molding is usually performed while delivering the container between the rotating conveyance wheels. For example, after the contents filling process, the filling amount, filling weight, etc. are inspected and the container that does not meet the standard range is discharged. The discontinuous arrangements are arranged in a continuous arrangement, that is, at regular intervals, and filled containers that meet the standard range are aligned, and the containers are delivered to the mouth sealing process.

  In the delivery of the container between the rotating transfer wheels, the gripping by the bottom gripper that grips and guides the bottom of the filling container, the gripping by the trunk gripper that grips and guides the trunk of the filling container, and the filling container The gripping by the gripper that grips the upper part can be appropriately selected or combined. The synthetic resin blow-molded multilayer container having a carbon-labeled surface layer according to the present invention can insert a gripper into the lower surface of the annular bulging portion so that the filled container can be stably and reliably gripped. It is possible to stably and reliably deliver containers between them, and it is not necessary to provide a guide plate or a guide groove that is often used in combination with gripping with a bottom gripper or gripping with a trunk gripper.

V. Characteristics of a synthetic resin blow-molded multilayer container having a carbon-labeled surface layer The synthetic resin blow-molded multilayer container of the present invention comprising a mouth, an annular recess, a shoulder, a trunk, and a bottom sequentially along the container axial direction And: i) The layer constitution of the multilayer container comprises at least an inner surface layer containing an ethylene-based resin, a barrier layer, and an outer surface layer containing an ethylene-based resin in this order from the inside of the container; ii) The mouth portion has a male thread region on the outer peripheral surface; iii) The annular recess is smaller in diameter than the male thread region and then expanded to be connected to the shoulder portion; iv) The shoulder portion is annular in the upper end. V) The annular bulging portion is formed such that the inner surface of the inner surface layer is bent toward the outside of the container along the container axial direction, and then bent toward the inside of the container. 20 to 55% of the thickness of the mouth And vi) at least one surface layer containing an ethylene-based resin includes, as a resin component, low-density polyethylene, an ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ , and A carbon-labeled surface layer comprising a resin composition containing at least one selected from the group consisting of high-density polyethylene and having a modern carbon ratio of 0 to 8 pMC as defined in ASTM D6866-12 A synthetic resin blow-molded multilayer container comprising a multilayer container having excellent axisymmetric returnability.

(Axisymmetric return)
The synthetic resin blow-molded multilayer container having a carbon-labeled surface layer according to the present invention is a multilayer container excellent in axisymmetric returnability, which may hinder accurate gripping and delivery of the multilayer container in the transport process, There is no hindrance to the mounting, and there is no risk of unexpected troubles during handling of the multilayer container product filled with the contents, so that the production efficiency is improved.

The axisymmetric returnability of the blow molded multilayer container can be evaluated by the following methods (1) to (4).
(1) Fill a multilayer container with 500 cm ³ of water, erect vertically on a horizontal plane, hold the gripper so that the gripper contacts the lower surface of the annular bulge, and suspend the multilayer container. The test environment and the temperature of water shall be room temperature (20 ± 5 ° C.).
(2) Next, a pair of rocking motions in which the gripper is tilted +30 degrees from the horizontal and then tilted by −30 degrees is performed at a speed of 20 pairs per minute for 60 minutes, and then the filled water is drained. A multilayer container is a specimen (five).
(3) The specimen is erected vertically on a horizontal plane, cut vertically along the diameter from the mouth, photographed using an optical magnifier, and the opening angle of the opposing cross section (from the vertical The angle of deviation) is measured using a digital frequency meter or a commercially available protractor. The absolute value (unit: degree) of the difference between the measured opening angles of the opposed cross sections is calculated (arithmetic average value of five specimens) to obtain the absolute value arithmetic average (unit: degree) of the multilayer container.
(4) If the absolute value arithmetic average is within 3 degrees, the blow molded multilayer container is evaluated as “excellent in axial symmetry return”. When the absolute value arithmetic average exceeds 4 degrees, the blow-molded multilayer container is evaluated as “inferior in axial symmetry returnability”.
(5) If there is a multi-layer container sample in which the gripper is removed during the swinging operation, the test of (1) to (4) is performed again on the sample, but the fact that the retest has been performed is displayed. .

  The absolute value arithmetic average is ideally 0 degree, but if it is 0.5 to 2.5 degrees, it can be said that the axisymmetric returnability is particularly excellent. On the other hand, the blow-molded multilayer container having poor axisymmetric returnability has the contents of the mouth portion and the annular bulge portion deformed by the swinging operation performed by filling the multilayer container with water. In the production process of multi-layer containers filled with, there are problems in accurate gripping and delivery of multi-layer containers, problems in cap installation, and unexpected troubles in handling multi-layer container products filled with contents. May occur. When the absolute value arithmetic average exceeds 5 degrees, the frequency of the above troubles and troubles increases, and when the absolute value arithmetic average exceeds 7 degrees, the above troubles and troubles become remarkable.

[Inner wall non-adhesiveness]
The synthetic resin blow-molded multilayer container having a carbon-labeled surface layer of the present invention has a non-adhesive property on the inner wall of the container by containing an organic lubricant in the inner surface layer containing an ethylene-based resin in the annular bulge portion if desired. It can be set as the multilayer container which is excellent in. For example, when trying to discharge the contents from a container filled with a viscous content such as tomato ketchup, the desired amount of the contents can be discharged in a short time, so that the feeling of use is excellent and the contents Can be used without waste.

The container inner wall non-adhesiveness of the blow molded multilayer container can be evaluated and determined by the following methods (1) to (4).
(1) A multi-layer container is filled with 500 g of commercially available tomato ketchup (JAS special grade product), and is vertically erect on a horizontal plane to be used as samples (the number of samples is 5). The test environment and the temperature of the tomato ketchup are normal temperature (20 ± 5 ° C.).
(2) Invert the multi-layered container, allow the tomato ketchup, which is the contents, to fall freely and take out about 100 g, then immediately cover it and leave it in an inverted state for 10 minutes (inverted treatment). Next, the multilayer container is erected and allowed to stand for 24 hours, and the multilayer container is again allowed to stand for 10 minutes in an inverted state (erecting process). Taking out the tomato ketchup by free fall, the inversion process and the erecting process as one unit, the contents of the tomato ketchup are repeated for 5 units or 6 units until the bottle inner wall is removed, excluding the portion attached to the inner wall of the bottle.
(3) For multi-layer containers in which the tomato ketchup, which is the contents, has been removed without removing the inner wall of the bottle, the presence of the tomato ketchup on the inner surface of the multi-layer container is visually observed, and there is a tomato ketchup slipping on the inner surface. Is evaluated as “◯”, and the tomato ketchup without slipping down is left as “x”.
(4) The container inner wall non-adhesiveness of the blow molded multilayer container is evaluated and judged according to the following criteria. If the container inner wall non-adhesion is determined to be excellent or good, it can be said that the container inner wall non-adhesion is excellent.
<Criteria for non-adhesion of inner wall of container>
Excellent: All five specimens are evaluated as “◯”.
Good: 1-4 specimens are evaluated as “◯”.
Bad: All five specimens have a “x” rating.

  EXAMPLES The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited to the examples. The measuring method of the characteristic or physical property of the resin raw material and the synthetic resin blow-molded multilayer container in Examples and Comparative Examples is as follows.

[Density and MFR]
The density and MFR of the ethylene resin and EVOH were measured according to JIS K6922-2 or JIS K7210.

(Axisymmetric return)
The axisymmetric returnability of the blow molded multilayer container was evaluated by the following methods (1) to (4).
(1) The multi-layer container was filled with 500 cm ³ of water, vertically erected on a horizontal plane, held so that the gripper was in contact with the lower surface of the annular bulge, and the multi-layer container was suspended. The test environment and water temperature were normal temperature (20 ± 5 ° C.).
(2) Next, a pair of rocking motions in which the gripper is tilted +30 degrees from the horizontal and then tilted by −30 degrees is performed at a speed of 20 pairs per minute for 60 minutes, and then the filled water is drained. Multilayer containers were used as specimens (5).
(3) The specimen is erected vertically on a horizontal plane, cut vertically along the diameter from the mouth, photographed using an optical magnifier, and the opening angle of the opposing cross section (from the vertical The angle of deviation) is measured using a digital frequency meter or a commercially available protractor. The absolute value (unit: degree) of the difference between the measured opening angles of the opposing cross sections was calculated (arithmetic average value of five specimens) to obtain the absolute value arithmetic average (unit: degree) of the multilayer container.
(4) When the absolute value arithmetic average was within 3 degrees, the blow-molded multilayer container was evaluated as “excellent in axial symmetry returnability” (displayed as “◯”). When the absolute value arithmetic average exceeded 4 degrees, the blow-molded multilayer container was evaluated as “inferior in axial symmetry returnability” (indicated as “x”).
(5) If there is a multi-layer container sample in which the gripper is removed during the swinging operation, the test of (1) to (4) is performed again on the sample, but the re-test is displayed. .

[Inner wall non-adhesiveness]
The container inner wall non-adhesiveness of the blow molded multilayer container was evaluated and determined by the following methods (1) to (4).
(1) A multi-layered container was filled with 500 g of commercially available tomato ketchup (JAS special grade), and was vertically upright on a horizontal plane to prepare specimens (the number of specimens was five). The test environment and the temperature of the tomato ketchup were normal temperature (20 ± 5 ° C.).
(2) The multi-layer container was inverted, the tomato ketchup as the contents was freely dropped and about 100 g was taken out, immediately covered, and allowed to stand in an inverted state for 10 minutes (invert processing). Next, the multilayer container was erected and allowed to stand for 24 hours, and the multilayer container was again allowed to stand in an inverted state for 10 minutes (uprighting treatment). Taking out the tomato ketchup by free fall, the inversion process and the erecting process as one unit, the contents of the tomato ketchup were repeated until 5 units or 6 units until the tomato ketchup disappeared, excluding the portion attached to the inner wall of the bottle.
(3) For multi-layer containers in which the tomato ketchup, which is the contents, has been removed without removing the inner wall of the bottle, the presence of the tomato ketchup on the inner surface of the multi-layer container is visually observed, and there is a tomato ketchup slipping on the inner surface. Was evaluated as “◯”, and the tomato ketchup did not slide down and remained attached was evaluated as “x”.
(4) Evaluation / determination of non-adhesion of the inner wall of the blow molded multilayer container was performed according to the following criteria.
<Criteria for non-adhesion of inner wall of container>
Excellent: All five specimens are evaluated as “◯”.
Good: 1-4 specimens are evaluated as “◯”.
Bad: All five specimens have a “x” rating.

[Example 1]
Using a plurality of extruders and an annular die, a cylindrical parison that has an outer surface layer / adhesive layer / barrier layer / adhesive layer / recovery layer / inner surface layer each having the following composition is extruded and rotary type A synthetic resin blow-molded multilayer container (hereinafter referred to as “multi-layer container”) manufactured by a direct blow molding of a multilayer structure having an inner volume of 540 cm ³ , in which a mouth, an annular recess, a shoulder, a trunk, and a bottom are integrally molded. , Sometimes referred to as “multilayer container”). The mouth of the multi-layer container has an outer diameter of 23 mm, an inner diameter of 20.2 mm, a thickness (thickness of a portion in the male screw region where no male screw exists) 1.4 mm, and a length in the container axial direction of 12 mm. And had a male thread region with a length of 8 mm along the container axis. In addition, the outer diameter of 41 mm is provided at the upper end of the shoulder portion that expands from the annular concave portion having an outer diameter of 22.5 mm, a thickness of 1.4 mm, and a length of 2.5 mm in the container axial direction. An annular bulge having a length of 2 mm in the container axial direction was provided. The annular bulge has a thickness formed by bending the inner surface of the inner surface toward the outer side of the multilayer container at a maximum depth of about 9 mm along the axial direction of the multilayer container, and then bending toward the inner side of the multilayer container. The thin portion was about 0.42 mm (corresponding to 30.0% with respect to the thickness of the mouth portion). The body of the multilayer container had an outer diameter of 60 mm and an inner diameter of 59 mm (that is, a thickness of 0.5 mm). The mass of the multilayer container was 20 g.

(1) Surface layer (the inner surface layer containing ethylene resin and the outer surface layer containing ethylene resin had the same thickness.) [Inner surface and outer surface of mouth, annular recess, shoulder, trunk, and bottom The surface composition is the same. ]:
As an ethylene-based resin, a high-pressure method low-density polyethylene derived from fossil fuel [Ziegler-Natta catalyst polymerization brand name EG0921 for blow molding manufactured by Brasschem, density 921 kg / m ³ , MFR (temperature 190 ° C., load 2.12 N) 0. 9g / 10min, modern carbon ratio 0pMC. Hereinafter, it may be referred to as “fossil fuel-derived LDPE1”. ] 75% by mass and high-density polyethylene derived from fossil fuel [Novatech (registered trademark) HD manufactured by Nippon Polyethylene Co., Ltd., Ziegler-Natta catalyst polymerization brand name KB285N, density 964 kg / m ³ , MFR (temperature 190 ° C., load) 2.12N) 0.2 g / 10 min, modern carbon ratio 0 pMC. Hereinafter, it may be referred to as “fossil fuel-derived HDPE”. ] Using a resin component consisting of 25% by mass,
As an organic lubricant, an unsaturated fatty acid amide, more specifically, an oleic acid amide (hereinafter sometimes referred to as “lubricant”) which is a fatty acid amide having an unsaturated cis carbon double bond, is 1000 ppm relative to the resin component. It mix | blended so that it might become. The modern carbon ratio of the resin composition forming the surface layer was 0 pMC.

(2) EVOH layer (barrier layer): trade name EVAL (registered trademark) manufactured by Kuraray Co., Ltd. [an ethylene / vinyl alcohol copolymer having an ethylene content of 44 mol%. Density 1140 kg / m ³ , MFR (temperature 190 ° C., load 21.18 N) 1.7 g / 10 min, crystal melting point 165 ° C.]

(3) Recovery layer: Resin obtained by excising the container head (= bag portion) generated when direct blow molding the multilayer container manufactured according to the present embodiment and pulverizing it with a crusher (recovered resin) Was used as a raw material.

(4) Adhesive layer: maleic anhydride-modified polyolefin manufactured by Mitsubishi Chemical Corporation, trade name Modic (registered trademark)

  The thickness ratio of the layers (1) to (4) was 75: 4: 20: 1. Table 1 shows the evaluation / determination results of the axisymmetric returnability of the multilayer container and the non-adhesion of the inner wall of the container together with the modern carbon ratio of the surface layer.

[Example 2]
Example 1 except for changing the composition of the surface layer in which the resin component of the ethylene-based resin contained in the surface layer (inner surface layer and outer surface layer) was changed to a synthetic resin composed of 100% by mass of fossil fuel-derived LDPE1 In the same manner as above, a synthetic resin blow molded multilayer container was obtained. Table 1 shows the evaluation / determination results of the axisymmetric returnability of the multilayer container and the non-adhesion of the inner wall of the container together with the modern carbon ratio of the surface layer.

[Example 3]
The resin component of the ethylene-based resin contained in the surface layer (inner surface layer and outer surface layer) is replaced with fossil fuel-derived LDPE1, and a metallocene low-density polyethylene derived from fossil fuel [Sumikasen (registered trademark) manufactured by Sumitomo Chemical Co., Ltd. ) EP, brand name CU5003, density 928 kg / m ³ , MFR (temperature 190 ° C., load 2.12 N) 0.4 g / 10 min, modern carbon ratio 0 pMC. Hereinafter, it may be referred to as “fossil fuel-derived LDPE2”. A blow molded multilayer container made of synthetic resin was obtained in the same manner as in Example 2 except that the composition of the surface layer was changed to 100% by mass. Table 1 shows the evaluation / determination results of the axisymmetric returnability of the multilayer container and the non-adhesion of the inner wall of the container together with the modern carbon ratio of the surface layer.

[Example 4]
Instead of fossil fuel-derived LDPE1, the resin component of the ethylene-based resin contained in the surface layer (inner surface layer and outer surface layer) is an ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ derived from fossil fuel. Linear low-density polyethylene that is a coalescence product (trade name ULTZEX (registered trademark) manufactured by Prime Polymer Co., Ltd., brand name 3520L, density 931 kg / m ³ , MFR (temperature 190 ° C., load 2.12 N) 2.1 g / 10 Min, modern carbon ratio 0pMC. Hereinafter, it may be referred to as “fossil fuel-derived LLDPE”. A blow molded multilayer container made of synthetic resin was obtained in the same manner as in Example 2 except that the composition of the surface layer was changed to 100% by mass. Table 1 shows the evaluation / determination results of the axisymmetric returnability of the multilayer container and the non-adhesion of the inner wall of the container together with the modern carbon ratio of the surface layer.

[Example 5]
The resin component of the ethylene-based resin contained in the surface layer (inner surface layer and outer surface layer) is replaced with fossil fuel-derived LDPE1, and a metallocene low-density polyethylene derived from fossil fuel [trade name kernel manufactured by Nippon Polyethylene Co., Ltd. ( (Registered trademark) Brand name KF282, density 915 kg / m ³ , modern carbon ratio 0 pMC. Hereinafter, it may be referred to as “fossil fuel-derived LDPE3”. A blow molded multilayer container made of synthetic resin was obtained in the same manner as in Example 2 except that the composition of the surface layer was changed to 100% by mass. Table 1 shows the evaluation / determination results of the axisymmetric returnability of the multilayer container and the non-adhesion of the inner wall of the container together with the modern carbon ratio of the surface layer.

[Example 6]
The synthesis was performed in the same manner as in Example 1 except that the extrusion speed and blow pressure of the cylindrical parison were adjusted, and the thickness of the annular bulge was changed to 47.3% with respect to the thickness of the mouth. A resin blow molded multilayer container was obtained. Table 1 shows the evaluation / determination results of the axisymmetric returnability of the multilayer container and the non-adhesion of the inner wall of the container together with the modern carbon ratio of the surface layer.

[Example 7]
The composition of the surface layer was changed by changing the resin component of the ethylene-based resin contained in the surface layer (inner surface layer and outer surface layer) to 100% by mass of fossil fuel-derived HDPE, and Except for the change in the shape of the multi-layer container in which the thickness of the annular bulging portion was changed to 35.0% with respect to the thickness of the mouth by adjusting the extrusion speed and the blow pressure, A blow molded multilayer container made of synthetic resin was obtained. Table 1 shows the evaluation / determination results of the axisymmetric returnability of the multilayer container and the non-adhesion of the inner wall of the container together with the modern carbon ratio of the surface layer.

[Example 8]
Except for the change in the shape of the multilayer container in which the extrusion speed and blow pressure of the cylindrical parison were adjusted to change the thickness of the annular bulge to 28.0% with respect to the thickness of the mouth, Example 6 and Similarly, a synthetic resin blow molded multilayer container was obtained. Table 1 shows the evaluation / determination results of the axisymmetric returnability of the multilayer container and the non-adhesion of the inner wall of the container together with the modern carbon ratio of the surface layer.

[Example 9]
Olein, which is an organic lubricant, and a change in the shape of the multilayer container in which the thickness of the annular bulge is changed to 28.0% with respect to the thickness of the mouth by adjusting the extrusion speed and blow pressure of the cylindrical parison A synthetic resin blow molded multilayer container was obtained in the same manner as in Example 1 except that the composition of the surface layers (inner surface layer and outer surface layer) that did not contain acid amide was changed. Table 1 shows the evaluation / determination results of the axisymmetric returnability of the multilayer container and the non-adhesion of the inner wall of the container together with the modern carbon ratio of the surface layer.

[Comparative Example 1]
By adjusting the extrusion speed and blow pressure of the cylindrical parison (the blow pressure was set high), the thickness of the annular bulging portion was changed to 15.0% with respect to the thickness of the mouth portion. Change, and in place of fossil fuel-derived LDPE1, plant-derived linear low-density polyethylene [brand name SSL118 manufactured by Brasschem, density 916 kg / m ³ , MFR (temperature 190 ° C., load 2.12 N) 1.0 g / 10 minutes, crystal melting point 190 ° C., biotinylation rate 87% (modern carbon ratio is calculated as 107 pMC × 0.87 = 93.1 pMC). Hereinafter, it may be referred to as “plant-derived LLDPE”. And a synthetic resin blow in the same manner as in Example 1 except that the composition of the surface layers (inner surface layer and outer surface layer) that did not contain oleic acid amide as an organic lubricant was changed. A molded multilayer container was obtained. The modern carbon ratio of the resin composition forming the surface layer was 69.8 pMC (calculated as 107 pMC × 0.87 × 0.75 + 0 pMC × 0.25 = 69.82 pMC). Table 1 shows the evaluation / determination results of the axisymmetric returnability of the multilayer container and the non-adhesion of the inner wall of the container together with the modern carbon ratio of the surface layer.

[Comparative Example 2]
By adjusting the extrusion speed and blow pressure of the cylindrical parison (the blow pressure was set low), the thickness of the annular bulging portion was changed to 60.0% with respect to the thickness of the mouth portion. A synthetic resin blow molded multilayer container in the same manner as in Example 1 except for the change and the change of the composition of the surface layers (inner surface layer and outer surface layer) that did not contain oleic acid amide as an organic lubricant. Got. Table 1 shows the evaluation / determination results of the axisymmetric returnability of the multilayer container and the non-adhesion of the inner wall of the container together with the modern carbon ratio of the surface layer. In the axisymmetric return evaluation test, there was one multi-layer container specimen in which the gripper was detached during the gripper swinging operation, and thus the specimen was retested.

From Table 1, a synthetic resin blow-molded multilayer container comprising a mouth part, an annular recess, a shoulder part, a body part, and a bottom part in order along the container axial direction: i) The layer structure of the multilayer container is at least ethylene-based An inner surface layer containing a resin, a barrier layer, and an outer surface layer containing an ethylene-based resin in this order from the inside of the container; ii) the mouth portion has a male thread region on the outer peripheral surface; iii) The annular recess is reduced in diameter from the male thread region and then expanded and connected to the shoulder; iv) The shoulder has an annular bulge at the upper end; v) The annular bulge is the inner surface layer. The inner surface of the container is formed by bending toward the outside of the container along the container axial direction, and then bending toward the inside of the container. At least one surface layer having a thickness of ˜55%; and vi) containing an ethylene-based resin Defining, as a resin component, low density polyethylene, ethylene · alpha-olefin copolymer having a density 912~935kg / ^{m 3,} and contains at least one selected from the group consisting of high density polyethylene, the ASTM D6866-12 A synthetic resin blow-molded multilayer container having a carbon-labeled surface layer of Examples 1 to 9 is characterized by comprising a resin composition having a modern carbon ratio of 0 to 8 pMC. Since the evaluation of “○” is an evaluation of “◯”, it was found to have excellent transportability. Therefore, the synthetic resin blow-molded multilayer containers having the carbon-labeled surface layers of Examples 1 to 9 are used for transportation between various processes after container molding, while the production speed of the synthetic resin blow-molded containers is increased. The gripping by gripper insertion can be performed stably and reliably, and the predetermined posture state of the multilayer container can be maintained. Furthermore, when the synthetic resin blow-molded multilayer container having the carbon-labeled surface layer of Examples 1 to 8 containing a lubricant is filled with a viscous content such as tomato ketchup, Since it was possible to discharge the desired amount so that the contents could not be seen visually in a short time, it was found that the multilayer container is excellent in feeling of use and can use the contents without waste.

  On the other hand, the thickness of the annular bulging portion is a ratio of 15.0% with respect to the thickness of the mouth portion, and the synthetic resin blow molded multilayer container of Comparative Example 1 in which the surface layer does not contain an organic lubricant, The absolute value arithmetic average of the axisymmetric returnability was 7.0 degrees, and the evaluation was “x”, and thus it was found that the material did not have excellent transportability. The synthetic resin blow-molded multilayer container of Comparative Example 1 stably and reliably performs gripping by gripper insertion during conveyance between processes after container molding while speeding up the production of the synthetic resin blow-molded container. It is evaluated that the predetermined posture state of the multilayer container cannot be maintained. In addition, the synthetic resin blow molded multilayer container of Comparative Example 1 does not contain a lubricant and, as a result, cannot maintain the predetermined posture state of the multilayer container, for example, viscous contents such as tomato ketchup When the container is filled, it has been found that the contents are a multi-layer container in which the contents cannot slide down and remain attached.

  The synthetic resin blow-molded multilayer container of Comparative Example 2 in which the thickness of the annular bulging portion is 60.0% of the thickness of the mouth portion and the surface layer does not contain an organic lubricant is axially symmetric. In the returnability evaluation test, there was one multi-layer container specimen in which the gripper was detached during the gripper swinging operation, and therefore the test had to be performed again. The cause is not always clear, but because the multi-layer container was molded by setting the blow pressure low in blow molding, molding failure occurred where the shape of the tip of the bottom surface of the annular bulge did not match the shape of the molding die. As a result, it was inferred that the container was detached from the gripper. The synthetic resin blow-molded multilayer container of Comparative Example 2 stably and reliably grips by inserting a gripper during conveyance between various processes after container molding, while the production speed of the synthetic resin blow-molded container is increased. It is evaluated that the predetermined posture state of the multilayer container cannot be maintained.

The present invention relates to a synthetic resin blow-molded multilayer container comprising a mouth, an annular recess, a shoulder, a trunk, and a bottom in order along the container axial direction: i) The layer structure of the multilayer container is at least ethylene-based An inner surface layer containing a resin, a barrier layer, and an outer surface layer containing an ethylene-based resin in this order from the inside of the container; ii) the mouth portion has a male thread region on the outer peripheral surface; iii) The annular recess is reduced in diameter from the male thread region and then expanded and connected to the shoulder; iv) The shoulder has an annular bulge at the upper end; v) The annular bulge is the inner surface layer. The inner surface of the container is formed by bending toward the outside of the container along the container axial direction, and then bending toward the inside of the container. At least one surface layer having a thickness of ˜55%; and vi) containing an ethylene-based resin Defining, as a resin component, low density polyethylene, ethylene · alpha-olefin copolymer having a density 912~935kg / ^{m 3,} and contains at least one selected from the group consisting of high density polyethylene, the ASTM D6866-12 modern carbon ratio from the synthetic resin composition is a 0~8pMC is; characterized in that, by a synthetic resin blow molding the multilayer container with a carbon labeled surface layer, CO ₂ emissions of visible " In addition to speeding up the manufacturing of synthetic resin blow-molded containers, gripping by gripper insertion is carried out stably and reliably when transporting between various processes after container molding. Blow-molded multilayer containers that can maintain the posture state, especially direct blow-molded multilayer containers, are provided, so that the industrial applicability is high.

  In particular, the present invention relates to a synthetic resin comprising an inner surface layer containing an ethylene-based resin in an annular bulging portion and the carbon-labeled surface layer formed from an ethylene-based resin composition containing an organic lubricant. When a blow molded multilayer container is used, a synthetic resin blow molded multilayer container having improved slipperiness, particularly a synthetic resin direct blow molded multilayer container, is provided, so that the industrial applicability is high.

DESCRIPTION OF SYMBOLS 1 Mouth part 11 Opening part 12 Male thread area 121 Male thread 2 Annular recessed part 3 Shoulder part 31 Annular bulging part 4 Trunk part

Claims (8)

A synthetic resin blow-molded multilayer container comprising a mouth, an annular recess, a shoulder, a body, and a bottom sequentially along the container axial direction:
i) The layer constitution of the multilayer container comprises at least an inner surface layer containing an ethylene-based resin, a barrier layer and an outer surface layer containing an ethylene-based resin in this order from the inside of the container;
ii) The mouth portion has a male thread region on the outer peripheral surface;
iii) the annular recess is reduced in diameter from the male thread region and then expanded to connect to the shoulder;
iv) The shoulder includes an annular bulge at the upper end;
v) The annular bulge is formed by bending the inner surface of the inner surface layer toward the outside of the container along the container axial direction, and then bending toward the inside of the container. And having a thickness of 20-55% of the thickness of the mouth; and
vi) At least one surface layer containing an ethylene-based resin is selected from the group consisting of low-density polyethylene, an ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ , and a high-density polyethylene as a resin component. Comprising a resin composition having a modern carbon ratio of 0 to 8 pMC as defined in ASTM D6866-12;
A synthetic resin blow-molded multilayer container comprising a carbon-labeled surface layer. Low density polyethylene, low density Density 910~930kg / ^m high-pressure low density polyethylene ³ or a density 910~928kg / ^{m 3} obtained by copolymerizing selectively α- olefins using metallocene catalyst A synthetic resin blow-molded multilayer container comprising a carbon-labeled surface layer according to claim 1 containing at least one kind of polyethylene.   A blow molded multilayer container made of a synthetic resin comprising a carbon-labeled surface layer according to claim 1 or 2 formed by direct blow molding.   A synthetic resin blow-molded multilayer container comprising a carbon-labeled surface layer according to any one of claims 1 to 3, wherein the barrier layer is formed from an ethylene / vinyl alcohol copolymer.   A synthetic resin blow-molded multilayer container comprising a carbon-labeled surface layer according to any one of claims 1 to 4, comprising a recovery layer.   The carbon-labeled surface layer according to any one of claims 1 to 5, further comprising an adhesive layer between one or both of the inner surface layer and the barrier layer, or between the barrier layer and the outer surface layer. Synthetic resin blow molded multilayer container.   The inner surface layer containing an ethylene-based resin in an annular bulge is formed from an ethylene-based resin composition containing an unsaturated fatty acid amide, a saturated fatty acid amide, or a mixture thereof, which is an organic lubricant. A blow molded multilayer container made of a synthetic resin, comprising the carbon-labeled surface layer according to any one of the above.   A synthetic resin blow-molded multilayer container comprising a carbon-labeled surface layer according to claim 7, which contains a fatty acid amide having an unsaturated cis structure carbon double bond as an organic lubricant.

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