JP6263431B2 - Synthetic resin blow molded multi-layer container with a bite support - Google Patents

Description

  The present invention relates to a synthetic resin multilayer 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, the present invention relates to a synthetic resin blow-molded multilayer container that includes a mouth portion, a body portion, and a bottom portion, and the bottom portion includes a bottom seal portion having a specific configuration.

  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, a synthetic resin blow-molded multilayer container comprising an inner surface layer and an outer surface layer containing a polyolefin resin, and a barrier layer, which is formed by direct blow molding (Synthetic resin direct blow molded multilayer containers) are known.

  In direct blow molding, a resin is heated and melted in an extruder, and a parison is extruded from a circular die (sometimes called an annular die or a circular die) into a cylindrical shape (sometimes called a tubular or annular shape). The parison is pinched off with a split mold, and the lower end of the parison is pinched off (cut out) and fused, and the compressed fluid is blown into the interior while the resin is softened, and blown to the cooled mold wall and cooled. This is a molding method.

  A synthetic resin blow-molded multilayer container (hereinafter sometimes referred to as “blow-molded multilayer container” or simply “multi-layer container”) filled with contents such as food is a container molding process (blow molding), and container transfer The final product is manufactured through a process, a content filling process 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.

  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. In the mouth sealing step, the cap mounting device rotates and tightens the cap around the mouth of the sealed container.

  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 may be provided with a guide plate or a guide groove.

  In recent years, in order to improve productivity, the speed of manufacturing apparatuses for multilayer containers has been 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 (a filling container or the like) cannot be maintained in an upright state, and may swing or tilt in various directions, for example, and the mouth seal may not be accurate. In some cases, it may fall over, which may reduce production efficiency.

  In the blow molded multilayer container, the pinch-off portion (cutting portion) formed at the bottom portion is formed by crushing and fusing the parison, so that sufficient strength may not be obtained. If the cut-off portion is damaged or deformed during handling such as transfer between processes in the production of a multilayer container, the container cannot be maintained in an upright state, and the production apparatus may need to be stopped. is there. In particular, in the case of filling containers, when filling the contents (for example, hot fill filling with a liquid at a temperature of about 80 ° C.), due to the weight or centrifugal force of the contents, In this case, the container cannot be maintained in an upright state, and the production apparatus may be stopped. Therefore, as disclosed in Patent Document 3 and Patent Document 4, the strength of the container bottom is increased by making the structure of the container bottom including the pinch-off part unique.

  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. (Patent Document 5). 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, it is a synthetic resin blow-molded multilayer container that can maintain the upright posture of the container reliably without causing the bottom crack of the container and the bulging of the bottom part. Production efficiency can be improved by preventing the occurrence of unforeseen troubles during handling of multi-layer container products filled with the contents without causing any trouble in gripping and delivery. There has been a demand for a synthetic resin blow-molded multilayer container, particularly a direct blow-molded multilayer container, which does not cause breakage or deformation of the bottom of the container during distribution and use by consumers.

JP-A 63-237924 JP-A-7-32554 JP 52-30869 A No. 6-11164 Japanese Patent Laid-Open No. 6-72422

  An object of the present invention is to provide a blow molded multilayer container made of synthetic resin, particularly a direct blow molded multilayer container that can reliably maintain an upright posture of the container without causing a bottom crack of the container or swelling of the bottom.

  As a result of earnest research on solving the above-mentioned problems, the present inventors have made a synthetic resin blow molding comprising a mouth part, a body part, and a bottom part, and a bottom part having a specially configured bottom raising part and bottom seal part. It has been found that the problem can be solved by using a multilayer container, and the present invention has been completed.

That is, according to the present invention,
A synthetic resin blow-molded multilayer container comprising a mouth part, a body part and a bottom part in order along the axial direction of the container,
The layer configuration of the multilayer container includes at least an inner surface layer containing an ethylene-based polyolefin resin, an intermediate layer having a barrier layer, and an outer surface layer containing an ethylene-based polyolefin resin in this order from the inside of the container.
a) The bottom portion is surrounded by a circumferential grounding portion, and includes a planar bottom raising portion located inside the container along the axial direction from the grounding portion;
b) The bottom raised portion extends substantially linearly in a plane perpendicular to the axial direction of the bottom portion, and is connected to a bottom seal portion extending from the bottom raised portion toward the outside of the container along the axial direction;
c) The bottom seal is
i) The outer edge of the container along the axial direction extends from the circumferential grounding part toward the inner side of the container along the axial direction from the biting part. And a biting support portion that ends at the bottom raising portion,
ii) each of the outer surfaces of the biting support part is formed from an outer surface layer containing the ethylene-based polyolefin resin, and
iii) The ratio L / L0 of the length L of the cross section along the axial direction of the raised portion to the maximum length L0 of the cross section along the axial direction of the biting support portion is in the range of 0.8 to 1.2; And,
d) The bottom seal portion extends from the bottom-up portion at a position corresponding to both ends in the longitudinal direction extending substantially linearly toward the inside of the container along the axial direction, and is located most inside the container along the axial direction of the bottom-up portion. A convex portion whose apex is located further inward of the container along the axial direction with respect to the point to be done;
A synthetic resin blow-molded multilayer container having a bite-off support portion is provided.

  Moreover, according to this invention, the synthetic resin blow molding multilayer container of the following (1)-(10) is provided as an embodiment.

(1) The bottom seal portion is iv) the ratio D / L0 of the thickness D of the biting support portion to the maximum length L0 of the cross section along the axial direction of the biting support portion is in the range of 0.5 to 1.5. A blow molded multilayer container made of a synthetic resin provided with a certain biting support portion.
(2) A synthetic resin blow-molded multilayer comprising the bite-off support part that exposes the cross-section of the intermediate layer having two barrier layers on the outermost end surface outside the container along the axial direction of the bite-off support part. container.
(3) A synthetic resin blow-molded multilayer container provided with the bite-off support part, wherein the convex part includes an intermediate layer having a barrier layer.
(4) A synthetic resin blow-molded multilayer container provided with the above-described biting support portion whose cross-sectional shape perpendicular to the axial direction of the bottom portion is elliptical.
(5) A synthetic resin blow-molded multilayer container provided with the above-mentioned biting support portion in which the direction of the major axis of the ellipse is substantially the same as the direction in which the bottom seal portion extends substantially linearly.
(6) Synthetic resin provided with the bite-off support part having an arcuate shape in which the end part extending and extending toward the inner side of the container along the axial direction swells toward the inner side of the container along the axial direction Blow molded multilayer container.
(7) A synthetic resin blow-molded multilayer container comprising the bite-off support portion formed by direct blow molding.
(8) A synthetic resin blow-molded multilayer container, wherein the barrier layer includes the bite-off support portion formed of an ethylene / vinyl alcohol copolymer.
(9) A synthetic resin blow-molded multilayer container, wherein the intermediate layer includes the bite-off support portion provided with an adhesive layer on one or both of the barrier layers.
(10) A synthetic resin blow-molded multilayer container provided with the above-described bite-off support part provided with a recovery layer.

According to the present invention, a synthetic resin blow-molded multilayer container comprising a mouth part, a body part, and a bottom part in order along the axial direction of the container,
The layer configuration of the multilayer container includes at least an inner surface layer containing an ethylene-based polyolefin resin, an intermediate layer having a barrier layer, and an outer surface layer containing an ethylene-based polyolefin resin in this order from the inside of the container.
a) The bottom portion is surrounded by a circumferential grounding portion, and includes a planar bottom raising portion positioned inward of the container along the axial direction from the grounding portion; b) The bottom raising portion is formed on a surface orthogonal to the axial direction of the bottom portion. It extends in a substantially straight line and is connected to a bottom seal portion extending from the bottom raised portion toward the outside of the container along the axial direction; c) the bottom seal portion has i) an outer edge of the container along the axial direction. It has a biting portion located inside the container along the axial direction from the circumferential grounding portion, and a biting support portion extending from the biting portion toward the inside of the container along the axial direction and ending at the bottom-up portion. Ii) any outer surface of the bite-off support part is formed from the outer surface layer containing the ethylene-based polyolefin resin, and iii) relative to the maximum length L0 of the cross-section along the axial direction of the bite-off support part , Ratio L / of the length L of the cross section along the axial direction of the bottom raised portion L0 is in the range of 0.8 to 1.2; and d) from the bottom raised portion at a position corresponding to both ends of the bottom seal portion extending in a substantially linear shape toward the inside of the container along the axial direction. A biting support portion that extends and has a convex portion whose apex is further positioned inward of the container along the axial direction with reference to a point positioned inward of the container along the axial direction of the bottom raising portion; Synthetic resin blow-molded multi-layer container with a synthetic resin blow-molded multi-layer container, especially synthetic resin direct, which can maintain the upright posture of the container reliably without causing bottom cracking or bottom swelling of the container There is an effect that a blow molded multilayer container is provided.

Fig.1 (a) is a partial cross section front view of the synthetic resin blow molded multilayer container provided with the biting support part of this invention, and FIG.1 (b) is a partial cross section side view. FIG. 2 (a) is a sectional front view of the bottom of a synthetic resin blow-molded multilayer container having a bite-off support portion of the present invention, and FIG. 2 (b) is a right side convex portion of FIG. 2 (a). It is a typical expanded sectional view. It is a typical expanded sectional side view of the bottom part of the biting support part vicinity of the synthetic resin blow molding multilayer container provided with the biting support part of this invention. It is a photograph which shows the cross section of the bottom part containing the biting support part of the synthetic resin blow-molded multilayer container provided with the biting support part of this invention. It is a photograph which shows the cross section in the cut surface of an angle of 20 degrees with respect to the bottom parting line of the bottom part containing the biting support part of the synthetic resin blow molding multilayer container provided with the biting support part of this invention. It is a cross-sectional front view of the principal part of the bottom metal mold | die used in order to form the bottom part of a synthetic resin blow-molded multilayer container provided with the biting support part of this invention.

I. Layer structure of the synthetic resin blow molded multilayer container The layer structure of the synthetic resin blow molded multilayer container provided with the biting support portion of the present invention includes at least an inner surface layer containing an ethylene-based polyolefin resin and an intermediate layer having a barrier layer. And an outer surface layer containing an ethylene-based polyolefin resin from the inside of the container in this order. A synthetic resin blow molded multilayer container comprising at least an inner surface layer containing an ethylene-based polyolefin resin, an intermediate layer having a barrier layer, and an outer surface layer containing an ethylene-based polyolefin resin in this order from the inside of the container. As long as the container comprises three layers of an inner surface layer containing an ethylene-based polyolefin resin, an intermediate layer having a barrier layer, and an outer surface layer containing an ethylene-based polyolefin resin in this order from the inside of the container, for example, A multilayer container provided with one or more layers such as a recovery layer, which will be described later, between the three layers (may be one layer or a plurality of layers), and any one of the three layers, for example, It means that it may be a multilayer container having a plurality of barrier layers.

1. Inner Surface Layer Containing Ethylene Polyolefin Resin Synthetic Resin Blow Molded Multilayer Container (hereinafter referred to as “Synthetic Resin Blow Molded Multilayer Container” or “Inventive Multilayer Container”) Is a multilayer container having an inner surface layer containing an ethylene-based polyolefin resin. As the ethylene-based polyolefin resin contained in the inner surface layer, an ethylene-based polyolefin 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); polyolefins such as; These resins can be used alone or as a blend with other resins.

  Preferred ethylene-based polyolefin resins include (i) low density polyethylene, (ii) propylene / α-olefin random copolymer obtained using Ziegler-Natta catalyst, (iii) high density polyethylene, (i) to ( A blend of at least two kinds of iii) or a blend of at least one of (i) to (iii) and another ethylene-based polyolefin resin can be employed. The ethylene-based polyolefin resins (i) to (iii) will be further described.

(1) (i) Low-density polyethylene (i) Low-density polyethylene (LDPE) that can be used as a preferred ethylene-based polyolefin resin in the present invention is a low-density polyethylene in a broad sense belonging to a so-called soft polyolefin, In addition to the known high-pressure low-density polyethylene (generally having a density of 910 to 930 kg / m ³ , preferably 912 to 930 kg / m ³ ), alpha-olefins, in particular using metallocene catalysts, in particular , Low density polyethylene ("metallocene low density polyethylene", "low density polyethylene by polymerization using metallocene catalyst", "metallocene catalyzed low density polyethylene") Or it may be called “M-LDPE” etc. Simply "metallocene low density polyethylene" may be referred. Generally density 910~928kg / ^{m 3,} preferably 912~925kg / ^{m 3.),} Further preferably used so-called linear low density polyethylene (LLDPE) can do.

The metallocene low-density polyethylene that can be preferably contained is an ethylene-based polyolefin obtained by polymerizing a mixed monomer containing ethylene as a main component and an α-olefin as a subcomponent in the presence of a metallocene catalyst. As the α-olefin, one or more of α-olefins having 3 to 40 carbon atoms, preferably 4 to 35 carbon atoms, more preferably 4 to 30 carbon atoms are used, for example, α-olefins having 4 to 8 carbon atoms. And an α-olefin having 10 to 26 carbon atoms can be used in combination, and a higher α-olefin having more than 20 carbon atoms may be included. The α-olefin is preferably present in the copolymer in an amount of 3 to 15 mol%. Metallocene low-density polyethylene is an ethylene / α-olefin copolymer that can also be referred to as ethylene / long-chain branched α-olefin / short-chain α-olefin copolymer, and is a long-chain branched derived from a higher α-olefin or the like. However, by acting to suppress the crystallinity of the resin, it is known that it has a low density that approximates that of a high-pressure method low-density polyethylene and is excellent in moldability. K6899-1: 2006 linear low density polyethylene (LLDPE; sometimes referred to as “linear low density polyethylene”), short chain branching derived from an α-olefin comonomer having 3 to 8 carbon atoms And an ethylene / α-olefin copolymer having a density of 912 to 935 kg / m ³ . 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. In addition, it can confirm with the following method that the synthetic resin blow molding multilayer container provided with the bite-off support part of this invention contains a 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.

  (I) The low density polyethylene has an MFR (temperature 190 ° C., load 21.18 N or 2.12 N), preferably 0.1 to 10 g / 10 minutes, more preferably 0.3 to 5 g / 10 minutes, still more preferably. In the range of 0.4 to 2 g / 10 min can be used. Further, (i) the low density polyethylene has a polydispersity (Mw / Mn) (hereinafter sometimes simply referred to as “polydispersity”), which is an index of molecular weight distribution, preferably 1.2 or more, more preferably In the range of 1.5 or more, more preferably 1.7 or more is effective in terms of improving moldability. The upper limit of the polydispersity is about 3.0. In addition, the density and MFR of polyethylene are measured according to JIS K6922-2, and the polydispersity is measured according to JIS K7252 (hereinafter, the measurement method is the same).

  (I) As the low density polyethylene, a synthetic product can be used, but a commercially available product may be used. Commercially available products include Novatec (registered trademark) LD (belonging to high pressure method low density polyethylene) and LL (belonging to linear low density polyethylene) manufactured by Nippon Polyethylene Co., Ltd., and Sumikasen (registered trademark) manufactured by Sumitomo Chemical Co., Ltd. ) EP (belonging to metallocene low density polyethylene), low density polyethylene manufactured by Mitsui DuPont Polychemical Co., Ltd.

(2) (ii) Ziegler-catalyzed propylene random copolymer (ii) Propylene / α-olefin random copolymer obtained using Ziegler-Natta catalyst (hereinafter referred to as “Ziegler-catalyzed propylene random copolymer”) Is a propylene / α-olefin random copolymer obtained using a Ziegler-Natta catalyst known as a catalyst for stereoregular polymerization of α-olefins.

The Ziegler-catalyzed propylene random copolymer has a content of monomer units obtained from propylene in the copolymer (hereinafter sometimes referred to as “propylene content”) of 100 to 94% by mass (however, 100% by mass). The content of monomer units obtained from α-olefin in the copolymer (hereinafter referred to as “α”) is preferably 99.7 to 95% by mass, more preferably 99.5 to 95.5% by mass. -Olefin content ") may be 0-6 mass% (excluding 0 mass%), preferably 0.3-5 mass%, more preferably 0.5-4.5 mass%. It is a ratio. Examples of the α-olefin that is a comonomer copolymerized with propylene include ethylene and / or an α-olefin having 4 to 20 carbon atoms. Specifically, ethylene, butene-1, pentene-1, hexene- 1, octene-1, 4-methylpentene-1, and the like. Two or more α-olefins can be used in combination. When the α-olefin content is in the above range, the synthetic resin blow-molded multilayer container can maintain practically good rigidity. A particularly preferred copolymer is a propylene / ethylene random copolymer having an ethylene content of 0.3 to 5% by mass, particularly 0.5 to 4.5% by mass. If the α-olefin content is too high, the temperature of the crystal melting point becomes low, and the desired strength may not be obtained, or the fluidity of the polymer may be lowered. The propylene content and the α-olefin content can be measured using ¹³ C-NMR (nuclear magnetic resonance spectrum).

The Ziegler-catalyzed propylene random copolymer has a density in the range of usually 880 to 930 kg / m ³ , preferably 885 to 925 kg / m ³ , and MFR (temperature 190 ° C., load 21.18 N) is usually 0.5. It is -100g / 10min, Preferably it is the range of 1-50g / 10min. If the MFR exceeds the above range, the impact strength of the synthetic resin blow molded multilayer container tends to be insufficient, and if the MFR is below the above range, the moldability may be poor. The polydispersity is usually in the range of 1.2 to 5, preferably 1.5 to 4.5, and more preferably 2 to 4 in terms of improving moldability.

  A synthetic product can be used as the (ii) Ziegler-catalyzed propylene random copolymer, but a commercial product may be used. As a commercial item, there is a brand name Nobren (registered trademark) manufactured by Japan Polyethylene Corporation.

(3) (iii) High density polyethylene (iii) High density polyethylene is generally a polyethylene having a density of 942 kg / m ³ or more. Usually, it is polyethylene with a density of 980 kg / m ³ or less, preferably 945 to 970 kg / m ³ , more preferably 948 to 965 kg / m ³ . The high density polyethylene has an MFR (temperature 190 ° C., load 21.18 N or 2.12 N), preferably 0.1 to 10 g / 10 minutes, more preferably 0.3 to 5 g / 10 minutes, and still more preferably 0.00. The thing in the range of 5-2 g / 10min can be used. A polydispersity in the range of preferably 2.5 or more, more preferably 4 or more, and even more preferably 5 or more is effective in improving moldability. The upper limit of the polydispersity is about 12.

  The high-density polyethylene can be a synthetic product, but can also be selected from commercially available products. Examples of commercially available products are low-pressure high-density polyethylene obtained using a so-called Ziegler-Natta catalyst, Novatec HD (registered trademark) manufactured by Nippon Polyethylene Co., Ltd., Hi-Zex (registered trademark) manufactured by Prime Polymer Co., Ltd. There is.

  As described above, (i) low-density polyethylene and (ii) Ziegler catalyst, which are preferable as the ethylene-based polyolefin resin contained in the inner surface layer of the synthetic resin blow-molded multilayer container provided with the bite-off support portion of the present invention. The propylene random copolymer or (iii) high-density polyethylene can be used alone or at least two blends of (i) to (iii) can be used. When using a blend, any one of (i) to (iii) is usually in the range of 99.9 to 0.1% by mass, preferably 95 to 5% by mass, more preferably 90 to 10% by mass. (The total amount is 100% by mass) and may be prepared according to the purpose.

(4) Other ethylene-based polyolefin resin Furthermore, as the ethylene-based polyolefin resin contained in the inner surface layer of the synthetic resin blow-molded multilayer container provided with the bite-off support portion of the present invention, at least one of (i) to (iii) A blend of one type and another ethylene-based polyolefin resin can also be used. Other ethylene-based polyolefin resins include, for example, a block copolymer composed of a polymer block composed of polypropylene and a polymer block composed of an ethylene / propylene copolymer obtained using a metallocene catalyst (hereinafter simply referred to as a block copolymer). Preferable examples include “metallocene catalyst block copolymers” and ethylene-based polyolefins obtained using metallocene catalysts (hereinafter sometimes simply referred to as “metallocene-catalyzed ethylene polyolefins”). Further, as other ethylene-based polyolefin resin, so-called high density or medium density polyethylene may be further used in combination. The content of these other ethylene-based polyolefin resins is usually 0.5 to 40 masses when the total amount of at least one of (i) to (iii) and other ethylene-based polyolefin resins is 100 mass%. %, Preferably 1 to 35% by mass, more preferably 2 to 30% by mass, depending on the purpose. Particularly preferred combinations include (ii) a composition of a Ziegler-catalyzed propylene random copolymer and a metallocene catalyst block copolymer, (i) a blend of low density polyethylene, metallocene catalyzed ethylene polyolefin and (iii) high density polyethylene. Things.

(5) Additive The ethylene-based polyolefin resin contained in the inner surface layer of the synthetic resin blow-molded multilayer container provided with the bite-off support portion of the present invention has improved molding processability or a synthetic resin blow-molded multilayer. In order to improve various characteristics of the container, various commonly used additives can be contained as necessary. 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.

[Lubricant]
The synthetic resin blow-molded multilayer container provided with the bite-off support portion of the present invention has an inner surface layer for improving slipperiness with viscous contents such as mayonnaise, ketchup and sauce filled therein, 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, a saturated fatty acid amide, or a mixture thereof, which is an organic lubricant, is more preferable. In particular, the synthetic resin blow-molded multilayer container provided with the bite-off support portion of the present invention is an unsaturated fatty acid amide, a saturated fatty acid amide or a mixture thereof, in which the inner surface layer containing an ethylene-based polyolefin resin at the bottom is an organic lubricant It is preferable that it is formed from the composition of the ethylene-type polyolefin resin containing this. Two or more of the above-mentioned lubricants may be used as a mixture. 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 the ethylene-based polyolefin resin contains a lubricant, more preferably an organic lubricant, the content thereof is usually 100 to 5000 ppm, preferably 150 to the resin component containing the ethylene-based polyolefin resin. It is 4500 ppm, More preferably, it is 200-4000 ppm.

2. The intermediate layer having a barrier layer The synthetic resin blow-molded multilayer container provided with the bite-off support portion of the present invention is provided with an intermediate layer having a barrier layer, thereby providing gas barrier properties such as oxygen barrier properties and carbon dioxide gas barrier properties, water or This is a synthetic resin blow molded multilayer container having a barrier property against water vapor, and can improve the storage stability of the contents filled in the multilayer container. The intermediate layer having a barrier layer means a layer composed of only the barrier layer, or a layer composed of one or more layers that are usually inseparably integrated with the barrier layer and the barrier layer. .

[Barrier layer]
As the resin for forming the barrier layer provided in the intermediate layer having the barrier layer, a resin conventionally used for forming a barrier layer in a synthetic resin blow molded multilayer container having a barrier property can be used. There is no particular limitation. For example, ethylene / vinyl alcohol copolymer or partially saponified ethylene / vinyl acetate copolymer (hereinafter, these may be collectively referred to as “EVOH”), polyglycolic acid, glycolic acid / lactic acid copolymer, Examples thereof include resins such as aromatic polyamide (MXD6) formed from metaxylylenediamine and adipic acid and polyvinylidene chloride, and EVOH is preferable. The intermediate layer having the barrier layer in the synthetic resin blow-molded multilayer container provided with the bite-off support portion of the present invention may usually have one barrier layer, but may also have 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. The presence of an EVOH layer preferably used as a barrier layer can be confirmed by staining EVOH with a solution containing iodine or the like and potassium iodide.

(Adhesive layer)
In addition to the barrier layer, the intermediate layer having the barrier layer can include one or more layers that are normally inseparably integrated with the barrier layer, and the one or more layers that are integrated are not particularly limited. . The intermediate layer is preferably provided with an adhesive layer on one or both of the barrier layers. That is, the synthetic resin blow-molded multilayer container provided with the biting support portion of the present invention can further include an adhesive layer interposed between the layers in order to increase the delamination strength of each layer constituting the multilayer container. Specifically, one or both of the barrier layers, more specifically, an inner adhesive layer interposed between the inner surface layer and the barrier layer directly or via another layer, or between the barrier layer and the outer surface layer A synthetic resin blow-molded multilayer container having an adhesive layer as one or both of the outer adhesive layers interposed directly or via other layers is preferred. 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. Furthermore, when the synthetic resin blow-molded multilayer container provided with the bite-off support portion of the present invention includes a recovery layer described later, it is preferable that an adhesive layer provided in the intermediate layer is adjacent to the recovery layer. . In addition, when the synthetic resin blow-molded multilayer container having the bite-off support portion of the present invention is provided with two or more barrier layers, an adhesive layer (intermediate adhesive layer) is adjacent to the two or more barrier layers. It is preferable to comprise.

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 0.5-20 micrometers, and is 1-10 micrometers in many cases.

3. Outer surface layer containing ethylene-based polyolefin resin The synthetic resin blow-molded multilayer container provided with the bite-off support portion of the present invention has an inner surface layer containing an ethylene-based polyolefin resin and a barrier layer as a layer structure. In addition to the layers, the multilayer container includes an outer surface layer containing an ethylene-based polyolefin resin in this order from the container inner side.

  As the ethylene-based polyolefin resin contained in the outer surface layer, the same resin as the ethylene-based polyolefin resin contained in the inner surface layer can be used. In addition, as with the inner surface layer, the ethylene-based polyolefin resin contained in the outer surface layer can be used as necessary to improve molding processability and improve various properties of the synthetic resin blow-molded multilayer container. In addition, it can contain a lubricant and other various additives that are generally used. 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. It is possible to prevent generation of non-defective products, production line stop, equipment failure, etc., and to hold the gripper inserted to hold the multilayer container stably and reliably. In addition, the surface gloss may be excellent.

  The inner surface layer containing the ethylene-based polyolefin resin and the outer surface layer containing the ethylene-based polyolefin resin provided in the synthetic resin blow-molded multilayer container provided with the biting support portion of the present invention may have different compositions, It may be of the same composition. Therefore, the synthetic resin blow-molded multilayer container provided with the biting support portion of the present invention can be formed from the same resin composition for the inner surface layer and the outer surface layer, that is, the surface layer.

4). Recovery layer The synthetic resin blow-molded multilayer container provided with the biting support portion of the present invention has at least an inner surface layer containing an ethylene polyolefin resin, an intermediate layer having a barrier layer, and an ethylene polyolefin resin as a layer structure. It is preferable that it is a synthetic resin blow-molded multi-layer container provided with an outer surface layer containing the above in this order from the inside of the container and further provided with a recovery layer. By providing the recovery layer, the strength of the synthetic resin blow-molded multilayer container can be increased, and the resource recyclability can be improved. The recovery layer can be a material recovered from the synthetic resin blow molded multilayer container itself provided with the biting support portion of the present invention (such as burrs, unnecessary parts of product containers, recovered products of containers outside the product standards), or the book It is a layer which contains as a main component the material collect | recovered in the process of manufacturing the synthetic resin blow-molded multilayer container provided with the biting support part of invention. In particular, the synthetic resin blow-molded multilayer container provided with the bite-off support portion of the present invention, after introducing blow air into a cylindrical molten parison to form a container-shaped blow-molded product, the head of the multilayer container (hereinafter, It is necessary to excise the “bag part”), but the excised bag part can be made into a recovery layer using a recovered resin powdered by a crusher as a raw material. In addition, each layer of the resin-molded blow molded multi-layer container provided with the resin collected by cutting away the portion other than the bag portion of the container-shaped blow molded product, the parison before blow molding, and further the bite-off support portion A material or raw material to be formed may be contained as a main component.

  The recovery layer may further contain raw materials for forming each layer of the synthetic resin blow molded multilayer container provided with the bite-off support portion of the present invention, for example, various resin raw materials, compounding agents, adhesives, and the like. .

5. Layer structure of blow molded multilayer container made of synthetic resinA blow molded multilayer container made of synthetic resin provided with the biting support portion of the present invention is at least an inner surface layer containing an ethylene-based polyolefin resin, an intermediate layer having a barrier layer, and It is a multilayer container provided with the outer surface layer containing an ethylene-type polyolefin resin in this order from the container inner side. Preferably, the intermediate layer is a synthetic resin blow-molded multilayer container including a bite-off support portion provided with an adhesive layer on one or both of the barrier layers, and further includes a bite-off support portion provided with a recovery layer. It is a blow molded multilayer container.

As a specific layer configuration, for example, a layer configuration of inner surface layer / recovery layer / intermediate layer (barrier layer) / outer surface layer, inner surface layer / intermediate layer (formed by inner adhesive layer / barrier layer). / Layer structure of outer surface layer, inner surface layer / intermediate layer (formed by barrier layer / outer adhesive layer) / Layer structure of outer surface layer, inner surface layer / intermediate layer (inner adhesive layer / barrier layer / outer side) Formed by an adhesive layer.) / Layer configuration of outer surface layer, inner surface layer / recovery layer / intermediate layer (formed by inner adhesive layer / barrier layer / outer adhesive layer) / layer configuration of outer surface layer, Further examples include a synthetic resin blow molded multilayer container having a layer structure of inner surface layer / recovery layer / intermediate layer (formed by barrier layer / intermediate adhesive layer / barrier layer) / outer surface layer. Therefore, to illustrate a more specific layer configuration of a synthetic resin blow molded multilayer container provided with the bite-off support portion of the present invention,
Inner surface layer / intermediate layer (barrier layer) / outer surface layer,
Inner surface layer / recovery layer / intermediate layer (barrier layer) / outer surface layer,
Inner surface layer / intermediate layer (formed by inner adhesive layer / barrier layer) / outer surface layer,
Inner surface layer / intermediate layer (formed by barrier layer / outer adhesive layer) / outer surface layer,
Inner surface layer / intermediate layer (formed by inner adhesive layer / barrier layer / outer adhesive layer) / outer surface layer,
Inner surface layer / recovery layer / intermediate layer (formed by inner adhesive layer / barrier layer / outer adhesive layer) / outer surface layer,
Inner surface layer / recovery layer / intermediate layer (formed by barrier layer / intermediate adhesive layer / barrier layer) / outer surface layer,
Inner surface layer / recovery layer / intermediate layer (formed by inner adhesive layer / barrier layer / outer adhesive layer) / recovery layer / outer surface layer,
Inner surface layer / intermediate layer (formed by inner adhesive layer / barrier layer / barrier layer / outer adhesive layer) / outer surface layer,
Inner surface layer / intermediate layer (formed by inner adhesive layer / barrier layer / intermediate adhesive layer / barrier layer / outer adhesive layer) / outer surface layer,
Inner surface layer / recovery layer / intermediate layer (formed by inner adhesive layer / barrier layer / barrier layer / outer adhesive layer) / outer surface layer,
Inner surface layer / recovery layer / intermediate layer (formed by inner adhesive layer / barrier layer / intermediate adhesive layer / barrier layer / outer adhesive layer) / outer surface layer,
Inner surface layer / recovery layer / intermediate layer (formed by inner adhesive layer / barrier layer / barrier layer / outer adhesive layer) / recovery layer / outer surface layer, and
Examples of the layer structure include inner surface layer / recovery layer / intermediate layer (formed by inner adhesive layer / barrier layer / intermediate adhesive layer / barrier layer / outer adhesive layer) / recovery layer / outer surface layer. It is not limited to. In addition, as will be described later, the layer structure of the synthetic resin blow-molded multilayer container can be usually confirmed by the opening section of the mouth.

  The thickness of the synthetic resin blow-molded multilayer container provided with the bite-off support part of the present invention is not particularly limited, but the total thickness of the trunk part is usually 20 μm to 5 mm, preferably 100 μm to 3 mm, more preferably 200 μm to 1 mm. Is within the range. The synthetic resin blow-molded multilayer container provided with the bite-off support part of the present invention may have a uniform thickness as a whole, but the thickness may vary depending on the part. In general, it is preferable that the bottom portion of the container has a thickness larger than that of the trunk portion in order to maintain strength. The total thickness of the bottom is usually 20 μm to 6 mm, preferably 100 μm to 4 mm, more preferably 200 μm to 2 mm.

  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 provided in the intermediate 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 intermediate layer includes an adhesive layer, the total thickness of the adhesive layers (inner adhesive layer, outer adhesive layer, intermediate adhesive layer) is usually 0.005 to 2%, preferably 0.007 to 1.5%. Preferably it is 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 blow molded multilayer container made of synthetic resin provided with the biting support portion of the present invention is not particularly limited, but is usually 10 to 80%. , Preferably 15 to 75%, more preferably 20 to 70%, particularly preferably 25 to 65%.

II. Synthetic resin blow-molded multilayer container comprising a mouth part, a trunk part and a bottom part sequentially along the axial direction of the container The synthetic resin blow-molded multilayer container comprising the bite-off support part of the present invention comprises a mouth part, a trunk part and a bottom part. In a synthetic resin blow-molded multilayer container, the layer structure of the multilayer container includes at least an inner surface layer containing an ethylene-based polyolefin resin, an intermediate layer having a barrier layer, and The outer surface layer containing an ethylene-based polyolefin resin is provided in this order from the inside of the container, and a) the bottom is surrounded by a circumferential grounding part and is located on the inner side of the container along the axial direction from the grounding part. B) the bottom raised portion extends substantially linearly on a surface perpendicular to the axial direction of the bottom portion, and is connected to the bottom seal portion extending from the bottom raised portion toward the outside of the container along the axial direction. C) the bottom seal portion is i) a bite portion in which the outer edge of the container along the axial direction is positioned inward of the vessel along the axial direction from the circumferential grounding portion, and an axial direction from the bite portion to the axial direction; And ii) the outer surface of the bite support part formed from the outer surface layer containing the ethylene-based polyolefin resin. And iii) the ratio L / L0 of the length L of the cross section along the axial direction of the bottom raised portion to the maximum length L0 of the cross section along the axial direction of the biting support portion is in the range of 0.8 to 1.2. And d) extending from the bottom raised portion at a position corresponding to both ends of the bottom seal portion in a substantially linear shape to the inside of the container along the axial direction, and along the axial direction of the bottom raised portion. Along the axial direction with reference to the point located most inside the container Its apex vessel inwards has a convex portion located; it is a synthetic resin blow molding the multilayer container with a support-away eating characterized. That is, the synthetic resin blow-molded multilayer container provided with the bite-off support part of the present invention is a multilayer container that includes a mouth part, a trunk part, and a bottom part in order along the axial direction of the container, and the multilayer container has an upright posture. In this case, by sequentially providing the mouth portion, the trunk portion, and the bottom portion along the axial direction of the container from the upper side to the lower side, the circumferential grounding portion provided at the bottom portion, specifically, the bottom portion, It is a multi-layered container that can abut against and stand upright. The internal volume of the blow molded multilayer container of the present invention is the internal volume up to the mouth cut surface, and is not particularly limited, but is preferably 40 to 3000 cm ³ , more preferably 80 to 1500 cm ³ , and still more preferably 120 to 1000 cm ^3. Range.

  Hereinafter, the synthetic resin blow-molded multilayer container provided with the biting support portion of the present invention will be further described with reference to the drawings. In addition, all drawings are schematic cross-sectional views simplified to help understanding the aspect of the multilayer container of the present invention.

1. Mouth Portion A synthetic resin blow molded multilayer container having a bite-off support portion of the present invention includes a mouth portion 1 as shown in FIG. The mouth portion 1 usually has an opening 11 at the uppermost end along the axis (not shown) of the container, and the male screw region located below the opening 11 has a male screw outward from the peripheral surface thereof. The strip is bulging. The male thread is provided to attach a cap (lid) having a female thread on the inner peripheral surface after filling the contents into a synthetic resin blow-molded multilayer container and sealing the opening 11. The male thread may have a single thread structure, but it is necessary for reducing the amount of rotational operation required for attaching and detaching the cap (lid) and molding the mouth portion 1 of the synthetic resin blow molded multilayer container. In order to reduce the amount of such a synthetic resin material, a multi-thread structure such as a double thread structure may be employed.

  The length along the axial direction of the male thread region, that is, the length in the vertical direction is appropriately determined. The mouth portion 1 may be provided with a male thread region via a lid mounting guidance region provided below the opening 11 as necessary. In a synthetic resin blow-molded multilayer container, a neck ring or a flange functioning as a support ring is provided at the lower end of the mouth 1 of the multilayer container, the inner surface of which is smooth and convex outward. In some cases, the synthetic resin blow molded multilayer container provided with the biting support portion of the present invention, particularly the synthetic resin multilayer container formed by direct blow molding, employs a structure without a neck ring or flange portion. May be.

2. Body part The synthetic resin blow-molded multilayer container provided with the biting support part of the present invention comprises a body part 2 below the mouth part 1 as shown in FIG. The trunk portion 2 is a generally cylindrical portion that is connected to the mouth portion 1 via a shoulder portion that gradually expands in diameter along the axial direction from the mouth portion 1 so as to rise from the periphery of the bottom portion 3 to be described later. Although it connects with the bottom part 3, the shape and magnitude | size of the trunk | drum 2 are not specifically limited. For example, the trunk portion 2 may change in cross-sectional shape, diameter, or cross-sectional area along the axial direction, and may be connected to the bottom portion 3 so as to sequentially reduce the diameter along the axial direction.

3. As shown in FIG. 1, the synthetic resin blow-molded multilayer container having the bite-off support portion of the present invention is provided below the trunk portion 2, usually connected to the trunk portion 2, and provided with the bottom portion 3. The container is self-supporting. The contour shape of the bottom portion 3, that is, the cross-sectional shape orthogonal to the axial direction of the bottom portion 3 is not particularly limited, and can be self-supporting that is usually employed in a synthetic resin multilayer container such as a substantially circular shape, a substantially oval shape, or a substantially polygonal shape The contour shape of the bottom can be obtained. As the substantially polygon, a triangle, a quadrangle, a pentagon, a hexagon, or the like can be adopted, and a shape such as an octagon formed by cutting out four corners of a rectangle may be used. The synthetic resin blow-molded multilayer container provided with the bite-off support part of the present invention does not cause bottom cracking or bulge of the bottom part, and can maintain the upright posture of the container in the axial direction of the bottom part 3. The orthogonal cross-sectional shape is preferably circular or elliptical, and more preferably elliptical. The size of the bottom portion 3 in the present invention is not particularly limited. For example, when the contour shape of the bottom portion 3 is circular, the radius is usually in the range of 2 to 20 cm, often in the range of 3 to 15 cm. When the contour shape of the bottom 3 (cross-sectional shape orthogonal to the axial direction of the bottom 3) is an ellipse, the major axis is usually in the range of 2 to 25 cm, often in the range of 3 to 20 cm, and the minor axis is Usually in the range of 1.5-20 cm, often in the range of 2-15 cm.

As shown in FIGS. 1 to 3, the bottom part 3 provided in the synthetic resin blow-molded multilayer container provided with the biting support part of the present invention has the following characteristics. That is,
a) The bottom portion 3 is surrounded by a circumferential grounding portion 31 and includes a planar bottom raising portion 32 positioned inward of the container along the axial direction from the grounding portion 31; b) the bottom raising portion 32 is an axis of the bottom portion 3 Extending substantially linearly in a plane perpendicular to the direction and connected to a bottom seal portion 33 extending outward from the bottom-up portion 32 along the axial direction; c) the bottom seal portion 33 is i) its axial direction The outer edge of the container along the inner edge of the container is a bite 331 located inward of the container along the axial direction from the circumferential grounding part, and the bottom is raised from the bite part 331 toward the inner side of the container along the axial direction. And ii) the outer surface of the bite support part 332 is formed from the outer surface layer containing the ethylene-based polyolefin resin, and iii) the bite piece Section along the axial direction of the support portion 332 The ratio L / L0 of the length L of the cross section along the axial direction of the bottom portion 3 in the bottom raised portion 32 to the maximum length L0 is in the range of 0.8 to 1.2; and d) of the bottom seal portion 33 A point extending from the bottom-up portion 32 at a position corresponding to both ends in the longitudinal direction extending in a substantially straight line toward the inside of the container along the axial direction and based on the point located most inside the container along the axial direction of the bottom-up portion 32 And further having convex portions 321 and 321 ′ whose apexes are located inside the container along the axial direction.

[Circular contact section]
The bottom 3 provided in the synthetic resin blow-molded multilayer container provided with the biting support portion of the present invention includes a circumferential grounding portion 31 surrounding the bottom raising portion 32. The circumferential grounding portion 31 is circumferentially arranged in the vicinity of the outer periphery of the bottom 3 of the container, and directly plays a role of directly supporting the container. Therefore, the circumferential grounding portion 31 has a circumferential shape that is substantially similar to the cross-sectional shape perpendicular to the axial direction of the container of the bottom portion 3, for example, a circumferential grounding portion 31 having a substantially circular or substantially elliptical shape. It is. The circumferential grounding portion 31 may be a belt-like one that continuously protrudes with a width in the circumferential direction, or may be composed of three or more discontinuous protrusions that allow the container to stand on its own. This is a configuration well known as the configuration of the bottom of the container. The width of the belt-like shape, the height of the protrusion, the size, shape, and arrangement of the protrusion can be appropriately selected within a range that does not hinder the self-supporting of the container. For example, the three or more discontinuous protrusions may be circumferentially arranged at equal intervals, or may be circumferentially arranged so as to be line symmetric.

(Bottom raised part)
The bottom 3 provided in the synthetic resin blow-molded multilayer container having the bite-off support part of the present invention is surrounded by the circumferential grounding part 31 and is located on the inner side of the container along the axial direction from the grounding part 31. The bottom raising part 32 of a shape is provided. The bottom raised portion 32 in the multilayer container of the present invention is normally continuous from the circumferential grounding portion 31 in the region surrounded by the circumferential grounding portion 31 having, for example, a substantially circular or substantially elliptical outline. By being recessed from the inside of the container along the axial direction of the container along the axial direction of the container, that is, toward the upper side of the container in the upright position, in the region of the bottom part 3 and connected from the circumferential grounding part 31 via the transition surfaces of various shapes It is a planar portion in a raised state located inside the container along the axial direction from the grounding portion 31, and can have a conventionally known shape and size. For example, the bottom raised portion 32 may be a substantially horizontal plane located in the container along the axial direction from the grounding portion 31 (hereinafter, sometimes referred to as “dent”), or a direction orthogonal to the axial direction, that is, It may be a curved surface whose distance to be recessed changes in the radial direction of the bottom 3. Further, from the viewpoint of the mechanical strength of the bottom part 3 and the self-supporting property of the multilayer container made of synthetic resin, ribs that are arranged separately in the circumferential direction of the bottom part 3 and extend in the radial direction may be provided. In the multilayer container, as will be described later, since the bottom portion 3 is provided with the bite-off support portion 332, it can have the required strength, and therefore it is not always necessary to include the rib.

[Bottom seal part]
In the synthetic resin blow-molded multilayer container provided with the bite-off support part of the present invention, the bottom raising part 32 extends substantially linearly in a plane perpendicular to the axial direction of the bottom part 3, and the container extends from the bottom raising part 32 along the axial direction. A bottom seal portion 33 extending outward is provided. Further, the bottom seal portion 33 includes: i) a biting portion 331 whose outer edge along the axial direction is positioned inward of the vessel along the axial direction from the circumferential grounding portion 31, and the biting portion 331. And a biting support portion 332 that extends toward the inside of the container along the axial direction and ends at the bottom raising portion 32, and ii) each of the outer surfaces of the biting support portion 332 contains the ethylene-based polyolefin resin. Iii) the ratio L / L0 of the length L of the cross section along the axial direction of the bottom raised portion 32 to the maximum length L0 of the cross section along the axial direction of the biting support portion 332 is 0 .8 to 1.2; and extends from the bottom raised portion 32 at a position corresponding to both ends of the bottom seal portion 33 extending in a substantially linear shape toward the inside of the container along the axial direction. , Along the axial direction of the bottom raised portion 32 With the most protruding portion 321, 321 further its apex container inwardly along a point located inside of the container in the axial direction with reference to the position '; especially with the features.

  In the multilayer container of the present invention, the bottom seal portion 33 extending substantially linearly on the surface orthogonal to the axial direction of the bottom portion 3 and extending outward from the bottom raised portion 32 along the axial direction is blow molded, typically Specifically, when manufacturing a synthetic resin multilayer container by direct blow molding, which will be described later, the lower end of the parison is sandwiched by closing the blow mold, which is a split mold, and the lower end of the parison is cut and cut. In this case, the seal portion having a thickness formed by extending from the bottom raising portion 32 on the parting line toward the outside of the container along the axial direction by simultaneously crushing and fusing the parison flat. . That is, in the multi-layer container of the present invention, the bottom raising portion 32 extends substantially linearly on a surface orthogonal to the axial direction of the bottom portion 3 and extends from the bottom raising portion 32 toward the outside of the container along the axial direction. 33 is connected. Since the bottom seal portion 33 extends substantially linearly on the parting line as described above, when the cross-sectional shape orthogonal to the axial direction of the bottom portion 3 is an ellipse, It is preferable that the direction in which the bottom seal portion 33 extends substantially linearly is the same. The length of the bottom seal portion 33 extending in a substantially linear shape can be appropriately selected according to the size of the multilayer container, specifically, the size and the cross-sectional shape of the bottom portion 3 of the multilayer container. For example, when the cross-sectional shape of the bottom 3 is an ellipse, the length is usually in the range of 40 to 90%, and in many cases 50 to 80% of the major axis of the ellipse. In many cases, the length is in the range of 20 to 150 mm, and in most cases 30 to 100 mm.

[Eating part]
The bottom seal portion 33 includes a biting portion 331 whose outer edge along the axial direction is positioned inward of the container with respect to the circumferential grounding portion 31, and the container along the axial direction from the biting portion 331. And a biting support portion 332 that extends toward the end and ends at the bottom raising portion 32. That is, the bottom seal portion 33 sandwiches the lower end of the parison by closing the blow mold, which is a split mold, and bites and cuts the lower end of the parison (“pinch-off portion”). 331). The biting portion 331 corresponds to a terminal end portion of the container that goes from the bottom raising portion 32 toward the outside of the container along the axial direction. In the multilayer container of the present invention, the biting portion 331 has a circumferential shape when the outer edge of the container along the axial direction is inside the container from the circumferential grounding portion 31, that is, when the multilayer container is erected. It is located above the grounding portion 31. Therefore, when the multi-layer container of the present invention is erected on the grounding surface, there is no possibility that the biting portion 331 is grounded, so that the biting portion 331 or the bottom seal portion 33 is cracked by contacting the grounding surface. Absent. Further, even if the bottom raised portion 32 bulges slightly toward the outside of the container by filling the contents of the multilayer container of the present invention, the biting portion 331 and the bottom seal portion 33 are connected to the ground plane. Since the possibility of contact can be reduced, the concern of cracking at the bottom is reduced.

[Eating support part]
The bottom seal portion 33 in the multilayer container of the present invention has a biting support portion 332 that extends from the biting portion 331 toward the inside of the container along the axial direction and ends at the bottom raising portion 32. That is, the biting support portion 332 corresponds to a region between the biting portion 331 and the bottom raising portion 32. The biting support 332 sandwiches the lower end of the tubular parison by closing the blow mold, which is a split mold, and bites and cuts the lower end of the parison. At the same time, the parison is flattened and fused. Thus, the seal portion extends from the bottom-up portion 32 on the parting line and is formed in a shape and thickness corresponding to the cavity shape of the mold.

  Since the bite-off support part 332 is formed by crushing and fusing the parison flatly, the outer surface of the bite-off support part 332 is the outer surface layer of the parison, that is, the container. It is formed from an outer surface layer containing an ethylene-based polyolefin resin. On the other hand, as shown in FIG. 3, the internal layer structure of the biting support portion 332 is the thickness of the biting support portion 332 (the distance between the outer surfaces or the direction in which the bottom seal portion extends substantially linearly. D, corresponding to the maximum length of the cross section along the axial direction of the biting support portion 332 (the maximum length along the axial direction from the biting portion 331, and “height”) L0 and the length L of the cross section along the axial direction of the bottom raising portion 32 (the bottom raising portion 32 at a position corresponding to the maximum length of the cross section along the axial direction of the biting support portion 332). It is the length of the cross section along the axial direction, and can be said to correspond to the “thickness of the raised portion” at the position.) And the layer configuration and thickness of the multilayer container, and are not particularly limited. There is no bite It is preferable that a cross section of the intermediate layer having two barrier layers is exposed at the outermost end surface outside the container along the axial direction of the holding portion 332. In this case, in the end portion close to the outermost end surface on the outer side of the container along the axial direction of the biting support portion 332, the intermediate layer including the barrier layer is present in an arrangement substantially parallel along the axial direction. Since the two barrier layers are strongly bonded via the inner adhesive layer, the effect of suppressing the bottom cracking of the container and the swelling of the bottom portion is increased. In addition, the cross section of the intermediate layer having two barrier layers is exposed on the outermost end surface outside the container along the axial direction of the biting support portion 332, and the intermediate layer including the barrier layer is in the axial direction. Presence of a substantially parallel arrangement along the surface can be confirmed by staining the barrier layer (layer B in FIG. 3) with a solution containing iodine and potassium iodide. That is, as seen in a cross-sectional photograph of the bottom portion including the bite-off support portion of the synthetic resin blow-molded multilayer container having the bite-off support portion of the present invention shown in FIG. The dyed barrier layer (corresponding to B in FIG. 3) is substantially along the axial direction at the end portion close to the outermost end surface outside the container along the axial direction of the biting support portion. It can be confirmed that they exist in a parallel arrangement. Moreover, it corresponds to the bottom parting line (corresponding to the direction orthogonal to the paper surface in FIG. 3) including the bite support part of the synthetic resin blow-molded multilayer container provided with the bite support part of the present invention of FIG. On the other hand, as seen in the cross-sectional photograph of the cut surface at an angle of 20 °, the dyed barrier layer (corresponding to B in FIG. 3) passes from the upper bottom-up portion to the lower end via the biting support portion. It approaches from the left-right direction until it reaches the biting part (the outermost end surface outside the container along the axial direction of the biting support part), and the outermost part of the container outside along the axis direction of the biting support part It is assumed that the barrier layer is present in a substantially parallel arrangement along the axial direction at the end portion close to the end face. 4 and 5, the indefinitely shaped resin lump existing below is a so-called burr generated by biting, and as is well known, is cut out in the multilayer container of the present invention.

[Height and thickness of the biting support part]
The bottom seal portion 33 in the multilayer container of the present invention has a ratio L / L of the length L of the cross section along the axial direction of the bottom portion 3 of the bottom raised portion 32 to the maximum length L0 of the cross section along the axial direction of the biting support portion 332. L0 is in the range of 0.8 to 1.2, preferably in the range of 0.9 to 1.1. The synthetic resin blow-molded multilayer container provided with the biting support portion of the present invention is in the axial direction of the bottom portion 3 of the bottom raising portion 32 with respect to the maximum length (height) L0 of the cross section along the axial direction of the biting support portion 332. When the ratio L / L0 of the length L of the cross section along the above is within the above range, the upright posture of the container can be reliably maintained without causing the bottom crack of the container or the swelling of the bottom. If L / L0 is too large, there is little effect due to the multi-layer container having the bottom seal part 33 and the bite support part 332, and the bottom crack of the container and the bulge of the bottom part will easily occur, and the upright posture of the container will be increased. There is a risk that it cannot be reliably maintained. If L / L0 is too small, the length L of the cross section along the axial direction of the bottom portion 3 at the bottom raising portion 32 becomes small, so that the strength of the bottom portion 3 of the container is insufficient, and the bottom crack of the container and the bulging of the bottom portion are also caused. May occur, and it may not be possible to reliably maintain the upright posture of the container. Further, the thickness D of the biting support portion 332 (the length of the cross section perpendicular to the axial direction of the biting support portion 332 at a position corresponding to the maximum length of the cross section along the axial direction of the biting support portion 332 described above) Is the maximum length (height) L0 of the cross section along the axial direction of the biting support portion 332, the size of the length L of the cross section along the axial direction of the bottom portion 3 in the bottom raised portion 32, and the layer configuration of the container. The thickness can be selected appropriately in consideration of the thickness of the container, and although not particularly limited, the axis of the bite support 332 is selected from the viewpoint of suppressing the bottom crack of the container and the bulging of the bottom, and reliably maintaining the upright posture of the container. The ratio D / L0 of the thickness D of the biting support portion 332 to the maximum length L0 of the cross section along the direction is preferably in the range of 0.5 to 1.5, and in the range of 0.7 to 1.2. More preferably.

[Cross-sectional shape of the biting support part]
The cross-sectional shape (corresponding to the end face shape) along the direction in which the bottom seal portion 33 of the biting support portion 332 extends substantially linearly in the multi-layer container of the present invention includes the biting portion 331 and the biting support portion 332. The upper side and the lower side are determined by the shape of the bottom 3 of the bottom raising portion 32, which is an end portion extending and extending toward the inner side of the container along the axial direction, and there is no particular limitation. Trapezoidal, substantially bowl-shaped [the lower side of the cross section corresponding to the biting portion 331 is linear, and the upper side of the cross section corresponding to the bottom 3 of the bottom raising portion 32 is arcuate (arched). ] Or substantially fan-shaped [a shape in which the lower and upper sides of the cross section are arcuate (arched). ] Or the like. From the viewpoint of suppressing cracking of the bottom of the container and swelling of the bottom, positive maintenance of the container's upright posture, and ease of removal of the container after blow molding from the mold, It is preferably a substantially fan-shaped cross-sectional shape, more preferably a substantially fan-shaped cross-sectional shape. Therefore, it is preferable that the end portion where the biting support portion 332 extends toward the inside of the container along the axial direction has an arc shape that swells toward the inside of the container along the axial direction, and the radius of curvature of the arc shape is Usually, it is in the range of 40 to 100 mm, and in many cases 50 to 90 mm. In addition, when the biting portion 331 forms an arc shape, the radius of curvature of the arc shape is in the same range. Further, the cross-sectional shape in the thickness direction of the biting support portion 332 in the multilayer container of the present invention is usually a rectangular parallelepiped shape, but may be a square body shape, a tip cut V-shape, a tip cut bottom bulge shape, or the like. it can. The cross-sectional shape, height, and thickness of the biting support portion 332 can be strictly molded depending on the shape of the blow molding die, as will be described later.

[Protrusions extending toward the inside of the container along the axial direction]
Furthermore, as shown in FIG. 2 (a), the multilayer container of the present invention has a container inner side along the axial direction from the bottom raised portion 32 at a position corresponding to both ends of the bottom seal portion 33 extending in a substantially linear shape. And having convex portions 321 and 321 ′ whose apexes are further located inward of the container along the axial direction with reference to the point positioned most inward of the container along the axial direction of the bottom raised portion 32. Features. The convex portions 321 and 321 ′ are formed by sandwiching the lower end of the tubular parison by closing the blow mold, which is a split mold, when the synthetic resin multilayer container is manufactured by blow molding, and cutting the lower end of the parison. When the bottom seal portion 33 extending from the bottom raised portion 32 on the parting line is formed by cutting and fusing the parison flatly at the same time when cutting, the bottom seal portion 33 is still formed. The surplus parison and a part of the bottom raising portion 32 associated with the surplus parison are directed toward the inside of the container along the axial direction at a position corresponding to both ends of the bottom seal portion 33 extending in a substantially linear shape. By flowing, two convex portions are formed at both ends in the longitudinal direction of the bottom seal portion 33 so as to project apart from each other like demon corners. The apexes of the convex portions 321 and 321 ′ are located further inside the container along the axial direction with reference to the point located most inside the container along the axial direction of the bottom raising portion 32, that is, the end above the bottom raising portion 32 With the height of (vertex) as a reference, the vertices of the convex portions 321 and 321 ′ are positioned at higher positions. The shape, size, and thickness of the convex portions 321 and 321 ′ that are the corner portions are not particularly limited, but FIG. 2B is an enlarged sectional view of the right convex portion 321 ′ in FIG. The left side of FIG. 2B is the central axis direction of the container. ], It is usually a curved shape having a drop-like (tears-like) thickness. Moreover, you may make it form convex part 321 and 321 'of an appropriate shape by making a blow die have a cavity shape corresponding to the shape of convex part 321 and 321' desired. The shape, size, etc. of the convex portions 321, 321 ′ can be changed by adjusting the closing pressure of the blow mold when forming the bottom seal portion 33 and / or the shape, size, etc. of the bottom seal portion 33. However, the length along the axial direction beyond the bottom 3 in the bottom raised portion 32 is usually in the range of 2 to 10 mm, and in many cases 3 to 8 mm, and the length in the extending direction of the bottom seal portion 33 is usually 2 -12 mm, often in the range of 3-9 mm. The layer configuration of the convex portions 321 and 321 ′ is not particularly limited, but preferably has a layer configuration substantially the same as the layer configuration of the bottom portion 3 in the bottom raised portion 32 and has a curved structure-like form having the layer configuration. That is, when the convex portions 321 and 321 ′ include the intermediate layer having the barrier layer, the multilayer container of the present invention can have sufficient barrier properties even at the bottom. In addition, it is confirmed by dye | staining a barrier layer [The layer of B in FIG.2 and FIG.3] with the solution containing an iodine and potassium iodide that convex part 321 and 321 'are provided with the intermediate | middle layer which has a barrier layer. be able to. Therefore, the layer structure of the convex portions 321 and 321 ′ is a layer structure including an inner surface layer containing an ethylene-based polyolefin resin, an intermediate layer having a barrier layer, and an outer surface layer containing an ethylene-based polyolefin resin in this order. Good. The multilayer container of the present invention further has a convex part 321, 321 ′ extending inward of the container along the axial direction in the shape of a devil's corner, thereby further suppressing the bottom crack of the container and the swelling of the bottom part. It has become something that can be.

III. Method for Producing Synthetic Resin Blow Molded Multilayer Container A synthetic resin blow molded multilayer container having a bite-off support portion according to the present invention comprises a synthetic resin blow container having a mouth portion, a trunk portion and a bottom portion in order along the axial direction of the container. The multilayer structure of the multilayer container includes at least an inner surface layer containing an ethylene-based polyolefin resin, an intermediate layer having a barrier layer, and an outer surface layer containing an ethylene-based polyolefin resin from the inside of the container A) The bottom portion is surrounded by a circumferential grounding portion, and includes a planar bottom-up portion positioned inward of the container along the axial direction from the grounding portion; b) The bottom-up portion is a bottom portion of the bottom portion. Extending substantially linearly in a plane orthogonal to the axial direction and connected to the bottom seal portion extending outward from the bottom-up portion along the axial direction; c) the bottom seal portion i) along the axial direction Yong The outer edge of the bowl is located on the inner side of the container along the axial direction from the circumferential grounding part, and the biting part extends from the biting part toward the inner side of the container along the axial direction and ends at the bottom raising part. And ii) the outer surface of the biting support portion is formed from the outer surface layer containing the ethylene-based polyolefin resin, and iii) along the axial direction of the biting support portion. The ratio L / L0 of the length L of the cross section along the axial direction of the bottom raised portion to the maximum length L0 of the cross section is in the range of 0.8 to 1.2; and d) the substantially straight shape of the bottom seal portion Extending from the bottom raised portion at a position corresponding to both longitudinal ends extending inward to the inside of the container along the axial direction, and along the axial direction on the basis of the point located most inside the container along the axial direction of the bottom raised portion Furthermore, it has a convex part whose apex is located inside the container; As long as it is possible to obtain a resin blow molding multilayer container, a manufacturing method thereof is not limited. Therefore, as a method for producing a synthetic resin blow-molded multilayer container having a bite-off support portion of the present invention, a multilayer parison having a predetermined layer configuration, specifically, the same layer configuration as that of a normal multilayer container ( Hereinafter, a “multilayer parison” may be blow-molded in a split mold having a desired container-shaped cavity wall to obtain a multilayer synthetic resin blow-molded multilayer container as a blow-molded product. I can do it. 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 manufactured by injection molding as long as a synthetic resin blow-molded multi-layer container having the above-mentioned predetermined shape can be obtained. However, the multi-layer parison can be produced by melt extrusion molding (hereinafter referred to as “tubular” or “pipe”). And a direct blow molding method in which the multilayer parison coextruded by a melt extrusion molding method is subsequently blow-molded into a container shape. A method for obtaining a synthetic resin blow molded multilayer container (direct blow molded multilayer container) formed by direct blow molding will be described below.

1. Production of multi-layer parison Examples of methods for producing multi-layer parisons having a predetermined layer structure by co-extrusion include co-extrusion methods using a circular die, co-extrusion methods using a T die, and co-extrusion methods using inflation molding. However, when manufacturing a 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 multi-layer parison by the coextrusion method using an annular die, use the number of extruders corresponding to the type of resin, melt the resin corresponding to each layer and expand it in an annular shape, The molten resin is merged so as to be in a stacking order of a predetermined layer configuration. 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. That is, the supply rate (discharge rate or extrusion rate) of the molten parison from the annular die to the blow molding die, the composition and thickness of the inner surface layer and / or outer surface layer containing the ethylene-based polyolefin resin can be adjusted. it can. For example, the supply speed of the molten parison from the annular die to the blow mold can be controlled by a so-called parison controller that stretches a part of the molten parison or controls the speed of the molten parison in the vertical downward direction.

2. Blow molding When a container-shaped blow molded product is formed from a parison by blow molding, the lower end of the cylindrical multilayer parison coextruded by the above method is sandwiched between split molds, and cut and cut. Next, the lower end of the parison is sealed and sealed, and then the upper end of the parison is sandwiched between split molds, cut off, and then blown into an opening formed in the upper end of the parison to form a container shape. Next, a part that is not necessary in the multilayer container as a product, that is, a part (head or bag part) corresponding to the upper part of the opening 11 of the mouth part 1 of the multilayer container is cut out, so that the blow molding made of synthetic resin is performed. A multilayer container is obtained. In addition, the layer structure of a multilayer container can be confirmed by the upper end surface of the opening part 11 of the opening part 1 of the multilayer container normally formed by excising a bag part. A bottom seal portion 33 is formed along the parting line on the bottom portion 3 of the multilayer container integrally molded by blow molding as a trace of a cylindrical parison sandwiched between split molds and sealed at the lower end. Is done. In the synthetic resin blow-molded multilayer container of the present invention, the bottom seal portion 33 has a bite-off portion 331 and a specific bite-off support portion 332, and both longitudinal ends of the bottom seal portion 33 extend substantially linearly. It extends toward the inside of the container along the axial direction from the bottom-up portion at a position corresponding to the portion, and further toward the inside of the container along the axial direction with reference to the point located most inside the container along the axial direction of the bottom-up portion 32 It has the convex part 321 and 321 'in which the vertex is located. Therefore, as a split mold for forming the bottom portion 3 of the synthetic resin blow-molded multilayer container of the present invention, a pinch portion (331a, 331b in FIG. 6) corresponding to the shape of the biting portion 331, and a biting support portion What is necessary is just to use the split mold provided with the step part (332a, 332b of FIG. 6) corresponding to the shape and magnitude | size of 332 so that it may each oppose. The shape and size of the biting support portion 332 are strictly formed by the shape and size of the stepped portion. Further, the convex portions 321 and 321 ′ having a desired shape and size are formed by selecting the shape and size of the multilayer container, the shape and size of the bottom raising portion 32 and / or the bottom seal portion 33, mold clamping pressure, and the like. Therefore, it is not usually necessary to form a cavity having a shape and a size corresponding to the shape and size of the convex portions 321 and 321 ′ formed on the raised portion 32 on the split mold. However, if particularly desired, a cavity having an appropriate shape and size may be provided to form the convex portions 321 and 321 ′.

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 provided with the biting support portion of the present invention can be manufactured by direct blow molding. In the direct blow molding process, the multi-layer parison obtained by melting and coextrusion of the resin is adjusted to a temperature at which it can be expanded and deformed, then inserted into the cavity of a blow molding die, and a direct blow is performed by blowing pressurized gas or the like. Perform molding. 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 provided with the bite-off support part of the present invention is provided with a bottom part having a specific structure, so that direct shape control and adjustment are easy and reliable from the viewpoint of direct blow molding. It is preferable to be formed.

  The blow molded multilayer container made of synthetic resin provided with the biting support portion of the present invention can be produced by stretch blow molding if desired. 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 heat-resistant synthetic resin blow molded multilayer containers suitable for hot filling (hot fill) of contents, blow molding molds are used to prevent thermal shrinkage and deformation of the containers during heat filling. The temperature may be raised to 100 ° C. or higher and heat-treated (heat-fixed) 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. Transport and gripping of synthetic resin blow-molded multilayer containers Synthetic resin blow-molded multilayer containers manufactured by direct blow molding, etc. After filling the container, heating, sterilizing and cooling as necessary, and checking the filling amount etc., the container is transported to the mouth seal device, and in the mouth seal process, the mouth opening of the container is opened. Seal with sealing material to make a sealed container.

  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 provided with the bite-off support portion of the present invention does not cause bottom cracking or swelling of the bottom portion, so it is easy to maintain the filled container in an upright state, and therefore the rotating transport wheel 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.

IV. Characteristics of the synthetic resin blow molded multilayer containerThe present invention is a synthetic resin blow molded multilayer container having a mouth, a body part and a bottom part in order along the axial direction of the container, and the layer configuration of the multilayer container is at least , An inner surface layer containing an ethylene-based polyolefin resin, an intermediate layer having a barrier layer, and an outer surface layer containing an ethylene-based polyolefin resin in this order from the inside of the container. A) The bottom is a circumferential shape A planar bottom raising portion surrounded by the grounding portion and positioned inward of the container along the axial direction from the grounding portion; b) the bottom raising portion extends substantially linearly in a plane perpendicular to the axial direction of the bottom, and Connected to the bottom seal portion extending outward from the container along the axial direction; c) the bottom seal portion; i) the outer edge of the container along the axial direction is axial from the circumferential grounding portion Inward of the container along A biting part to be placed, and a biting support part extending from the biting part toward the inside of the container along the axial direction and ending at the bottom raising part, and ii) the outer surface of the biting support part is Formed of an outer surface layer containing the above-mentioned ethylene-based polyolefin resin, and iii) the length L of the cross section along the axial direction of the raised portion relative to the maximum length L0 of the cross section along the axial direction of the biting support portion The ratio L / L0 is in the range of 0.8 to 1.2; and d) the container inward along the axial direction from the bottom-up portion at a position corresponding to both ends in the longitudinal direction extending substantially linearly of the bottom seal portion A convex portion whose apex is further located in the container along the axial direction with reference to the point located most inward in the container along the axial direction of the bottom raised portion; The container will not crack at the bottom or bulge at the bottom. It is a multilayer container.

  The synthetic resin blow-molded multilayer container provided with the biting support part of the present invention is not necessarily clearly elucidated for the reason that it is a multilayer container in which bottom cracks are unlikely to occur. As a result of the fact that the parison is fused in a state where the laminated structure of the layers is kept relatively uniform in the support portion, it is presumed that a sufficiently large fusion strength is realized. In particular, when the shape of the mold and the clamping operation are adjusted so that the intermediate layer including the barrier layer can be fused in close proximity, for example, the adhesive effect provided by the adhesive layer provided in the intermediate layer is exhibited. Thus, it is assumed that a greater fusion strength can be obtained.

[Bottom crack]
The synthetic resin blow molded multilayer container provided with the bite-off support part of the present invention is a multilayer container that is unlikely to cause bottom cracks, and as described above, there is a problem in accurate gripping and delivery of the multilayer container in the transport process. , Cap installation is not hindered, and there is no risk of unexpected troubles during handling of multi-layer container products filled with contents, improving production efficiency and filling contents. It is a multilayer container in which the bottom of the container is not deformed even when the multilayer container product is manufactured, distributed to consumers, and used by consumers.

The effect on the bottom crack of the blow-molded multilayer container can be evaluated by the falling body strength test (1) to (4) below.
(1) Contents that do not exceed the amount tolerance (referred to as an error specified for the measurement related to the sale of a specific product) in a multilayer container (for example, an inner volume of 450 cm ³ up to the mouth cut surface). After filling an amount (for example, 500 g for tomato ketchup, 450 g for water, etc.) of water (ice water at a temperature of 0 ° C.) and welding an aluminum seal to the opening of the mouth, screw the cap Stop and install.
(2) A drop test is performed in which a multilayer container filled with water is dropped from a height of 1.2 m onto a horizontal base made of SUS304 (common name: 18Cr-8Ni) stainless steel. The drop test is performed by dropping a multi-layer container in an upright state, and then dropping the same multi-layer container in a horizontal state as one unit. )carry out.
(3) The presence or absence of cracks in the bottom seal portion at the bottom of the multilayer container is visually observed. In addition, when the crack of the bottom part seal part of the bottom part of a multilayer container is observed before the drop test which implements the dropping operation of (2) 10 units is completed, it is determined that there is a crack of the bottom seal part.
(4) When the drop test is performed on five multilayer containers, and there are no multilayer containers with cracks in the bottom seal (no one), the result of the drop strength test is “No crack” If there are one or more multi-layer containers having a crack in the bottom seal portion, the result of the falling body strength test is determined as “crack”.

  The blow molded multilayer container made of synthetic resin provided with the bite-off support part of the present invention is determined to have no cracks in the results of the drop strength test, and in the manufacture, distribution and use of multilayer containers filled with the contents No bottom cracks occur. On the other hand, if the result of the falling-body strength test is a multilayer container that is determined to be “cracked”, there is a risk that bottom cracks may occur in the manufacture, distribution, and use of the multilayer container filled with the contents.

[Protrusion test]
The synthetic resin blow-molded multilayer container having a bite-off support portion according to the present invention has a bottom expansion in the manufacture, distribution and use of a hot-fill multilayer container filled with contents, for example, filled with liquid at a temperature of about 80 ° C. In particular, as the bottom raised part bulges, the cut-out part is located outside the container along the axial direction of the container from the grounding surface of the multilayer container, so that it comes into contact with the ground. By being in the state, the multilayer container is prevented from standing upright, and there is no serious inconvenience in handling or production efficiency is not reduced. The presence or absence of swelling of the bottom portion (bottom raising portion) of the multi-layer container can be evaluated by the anti-protrusion test of (1) to (4) below.
(1) Inner volume (for example, 500 g for tomato ketchup, 450 g for water) that does not exceed the amount tolerance based on the provisions of the Measurement Law in a multilayer container (for example, an inner volume of 450 cm ³ up to the mouth cut surface) Etc.) is filled with water (ice water at a temperature of 0 ° C.), an aluminum seal is welded to the opening of the mouth, and the cap is screwed on and attached.
(2) The multilayer container filled with water is placed on a horizontal table made of SUS304 stainless steel so as to be in a horizontal state.
(3) Using a compression tester, the barrel adjacent to the bottom of the multilayer container filled with water is compressed vertically from above and the load on the tester is increased to continue pressing against the multilayer container. The load (unit: kg weight) of the testing machine when it is visually observed that there is a butt (bulging deformation) on the bottom (bottom raising part) of the multilayer container is defined as a butt test resistance.
(4) A butt-proof test is performed on five multilayer containers, and the average value is defined as the butt-proof test strength of the multilayer container.

  If the multi-layer container has a butt-proof strength of 10 kg or more, there is no risk that the bottom (bottom raised part) will bulge out in the production, distribution and use of the multi-layer container filled with the contents. Can be evaluated. On the other hand, if the strength of the multi-layer container is too small, the bottom (bottom raised part) may swell in the production, distribution and use of the multi-layer container filled with the contents. Efficiency is also reduced. The multi-layer container has a butt test resistance strength of preferably 15 kg weight or more, more preferably 20 kg weight or more. The upper end of the multi-layer container is not particularly limited, but is usually less than 50 kg weight, and often less than 45 kg weight.

[Erecting stability]
The synthetic resin blow-molded multilayer container provided with the bite-off support part of the present invention prevents the multilayer container from being upright due to cracks at the bottom and swelling of the bottom part in the production, distribution and use of the multilayer container filled with the contents. Thus, the container is excellent in upright stability without causing a major inconvenience in handling or reducing the production efficiency. That is, the synthetic resin blow-molded multilayer container is usually an upright container that can stand upright from the grounding surface by the grounding portion and can be in an upright state in which the axial direction of the container is perpendicular to the grounding surface. It tends to be preferred by consumers who often use containers placed on the table. Further, in the process of delivering the container during the transportation of the container, filling the container with the contents, or capping the container, the use of the upright container is expected to improve the production efficiency.

  The upright stability of the blow molded multilayer container can be evaluated by the following upright stability test. That is, the parting line direction of the multilayer container (which is an empty container) (when the bottom surface is elliptical, it is usually the major axis direction of the ellipse) is marked, and the container is made of SUS304 stainless steel. When the bottom surface in the direction perpendicular to the parting line direction of the container is elliptical on a horizontal table, it is generally in the direction of the minor axis of the ellipse. ), The container is tilted, the container is tilted, the pressure is released, and the sway of the container is settled [hereinafter sometimes referred to as “convergence time”. Unit: seconds]. The container is pressed at a height of 20 cm from the ground contact surface of the container so that the horizontal distance is 10 mm, and the arithmetic average value of the convergence time measured 10 times at room temperature is the convergence time of the blow molded multilayer container. To do. If the container falls, the test for that container is terminated. When the convergence time of the container is within 4 seconds, the evaluation of erecting stability is determined as “◯”, and when it exceeds 4 seconds, the evaluation of erecting stability is determined as “x”. A blow-molded multilayer container having an evaluation of upright stability of “x” may cause clogging or dropping of the container during the container transport process, resulting in a decrease in production efficiency.

  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-based polyolefin resin and EVOH were measured according to JIS K6922-2 or JIS K7210.

[Bottom crack (drop body strength test)]
The effect on the bottom crack of the blow molded multilayer container was evaluated by the falling body strength test of (1) to (4) below.
(1) Fill a multi-layer container (with an internal volume of 450 cm ³ up to the mouth cut surface) with an internal volume (450 g) of water (ice water at a temperature of 0 ° C.) that does not exceed the amount tolerance based on the measurement method. After welding an aluminum seal to the opening of the part, the cap was screwed on and attached.
(2) A drop test was performed in which a multilayer container filled with water was dropped from a height of 1.2 m onto a horizontal base made of SUS304 stainless steel. The drop test is performed by dropping a multi-layer container in an upright state, and then dropping the same multi-layer container in a horizontal state as one unit. )Carried out.
(3) The presence or absence of cracks in the bottom seal portion at the bottom of the multilayer container was visually observed. In addition, when the crack of the bottom seal part of the bottom part of a multilayer container was observed before the drop test which implements 10 units of the dropping operation of (2) was completed, it was determined that there was a crack in the bottom seal part.
(4) When the drop test is performed on five multilayer containers, and there are no multilayer containers with cracks in the bottom seal (no one), the result of the drop strength test is “No crack” When there are one or more multilayer containers having a crack in the bottom seal portion, the result of the falling body strength test was determined as “crack”.

[Protruding butt test strength]
The presence or absence of swelling of the bottom (bottom raised portion) of the blow-molded multilayer container was evaluated by the following anti-extrusion test (1) to (4).
(1) Fill a multi-layer container (with an internal volume of 450 cm ³ up to the mouth cut surface) with an internal volume (450 g) of water (ice water at a temperature of 0 ° C.) that does not exceed the amount tolerance based on the measurement method. After welding an aluminum seal to the opening of the part, the cap was screwed on and attached.
(2) The multilayer container filled with water was allowed to stand on a horizontal base made of SUS304 stainless steel so as to be in a horizontal state.
(3) Using a Tensilon universal material testing machine manufactured by Toyo Baldwin Co., Ltd., compressing the barrel adjacent to the bottom of the multilayer container filled with water vertically from above, increasing the load on the testing machine. Pressing on the multilayer container was continued. The load (unit: kg weight) of the testing machine when it was visually observed that the bottom portion (bottom raising portion) of the multilayer container had a protrusion (bulging deformation) was defined as a protrusion-proof test strength.
(4) The anti-protrusion test was conducted on five multilayer containers, and the average value was defined as the anti-protrusion test strength of the multilayer container.

[Erecting stability]
The upright stability of the blow molded multilayer container was evaluated by the following upright stability test. That is, a parting line direction of a multilayer container (which is an empty container) (when the bottom is an ellipse, it is usually an ellipse major axis direction) is marked, and the container is made of SUS304 stainless steel material. In the case where the bottom surface in the direction perpendicular to the parting line direction of the container is elliptical on a horizontal base made of metal, it is usually in the direction of the minor axis of the ellipse. ), The container was tilted, the pressure was released, and the time until the shaking of the container subsided (convergence time; unit: second) was measured. The container is pressed at a height of 20 cm from the ground contact surface of the container so that the horizontal distance is 10 mm, and the arithmetic average value of the convergence time measured 10 times at room temperature is the convergence time of the blow molded multilayer container. did. If the container collapsed, the test for that container was completed. When the convergence time of the container was within 4 seconds, the evaluation of erecting stability was determined as “◯”, and when it exceeded 4 seconds, the evaluation of erecting stability was determined as “x”.

[Example 1]
Using a plurality of extruders and an annular die, the layer constitution is: outer surface layer / intermediate layer (consisting of inner adhesive layer / barrier layer / outer adhesive layer) / recovery layer / inner surface layer each having the following composition. A synthetic resin blow-molded multilayer container manufactured by direct blow molding with an overall height of 200 mm and an internal volume of 450 cm ³ , in which a cylindrical parison is extruded and a mouth, body and bottom are integrally molded by a rotary direct blow molding machine As a result, a soft bottle with a trade name Bloace (registered trademark) 500 g specification manufactured by Kureha Co., Ltd. (hereinafter, simply referred to as “multilayer container” in Examples and Comparative Examples) was obtained. The mouth of the multilayer container has a thickness of 1.5 mm, and the body of the multilayer container has a substantially elliptical cross-sectional shape with a maximum diameter of 0.5 mm. The bottom of the multi-layer container has a substantially elliptical cross-sectional shape having a major axis of 56 mm and a minor axis of 41 mm, and is substantially above the grounding part extending from the grounding part and surrounded by a substantially elliptical grounding part having a major axis of 50 mm and a minor axis of 35 mm. The maximum height is 7 mm, and the bottom raising portion is 1.5 mm in length (thickness, L) of the cross section along the axial direction of the bottom raising portion. Further, the bottom raised portion is provided with a bottom seal portion having a length of 40 mm extending downward from the bottom raised portion along a parting line along the major axis of the sectional shape of the bottom portion and extending substantially linearly. , A length of 35 mm along the parting line, a cuboidal cross section having a maximum length (height, L0) of 1.5 mm and a thickness (D) of 1.5 mm along the axial direction of the biting support portion. The upper side and the lower side of the cross section along the parting line have an arch-shaped support portion having a curvature radius of 75 mm (L / L0 = 1.0, D / L0 = 1.0). . It was confirmed that the cross section of the intermediate layer having two barrier layers was exposed on the outermost end face outside the container along the axial direction of the biting support portion. Furthermore, the most container along the axial direction of the bottom raised portion extends from the bottom raised portion at a position corresponding to both ends in the longitudinal direction (interval 36 mm) of the bottom seal portion toward the inside of the container along the axial direction. The apex is located further inward of the container along the axial direction with respect to the point located inward (hereinafter sometimes referred to as “above the bottom-up portion”), and is formed in the shape of a devil's corner. Moreover, it had two convex parts provided with the intermediate | middle layer which is a substantially drop shape of height 4.7mm and length 5.1mm, and has a barrier layer. The mass of the multilayer container was 17.0 g.

(1) Surface layer (the inner surface layer containing an ethylene-based polyolefin resin and the outer surface layer containing an ethylene-based polyolefin resin have the same thickness.) [The composition of the inner surface and the outer surface of the mouth, trunk, and bottom is The same. ]:
As an ethylene-based polyolefin resin, a high-pressure low-density polyethylene [Novatec (registered trademark) LD manufactured by Nippon Polyethylene Co., Ltd .; density 920 kg / m ³ , melting point 111 ° C., MFR (temperature 190 ° C., load 21.18 N) 0.8 g / 10 minutes. Hereinafter, it may be expressed as “LDPE1”. As an unsaturated fatty acid amide that is an organic lubricant, oleic acid amide was blended to 1000 ppm with respect to the ethylene-based polyolefin resin.

(2) Intermediate layer (formed from inner adhesive layer / barrier layer / outer adhesive layer)
1) EVOH layer (barrier layer): trade name EVAL (registered trademark) manufactured by Kuraray Co., Ltd. [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.]
2) Inner adhesive layer and outer adhesive layer: Maleic anhydride-modified polyolefin manufactured by DuPont, trade name BYNEL (registered trademark) brand name series 4200 [density 920 kg / m ³ , graft modification rate 0.8 mass%, MFR (temperature 190) ° C, load 21.18 N) 2.5 g / 10 min]
(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.

  The thickness ratio of layers (1), (2) 1), (2) 2) (total of inner and outer adhesive layers) and (3) was 75: 4: 1: 20. Table 1 shows the results of evaluation / judgment of the bottom crack of the multi-layer container, the butt-out test strength and the upright stability.

[Example 2]
As the ethylene-based polyolefin resin forming the surface layer, metallocene low density polyethylene [Sumikasen (registered trademark) EP manufactured by Sumitomo Chemical Co., Ltd., trade name CU5001; density 923 kg / m ³ , melting point 107 ° C., MFR (temperature 190 ° C., load 21 .18N) 0.4 g / 10 min. Hereinafter, it may be expressed as “LDPE2”. ] A synthetic resin blow molded multilayer container was obtained in the same manner as in Example 1 except that the composition of the surface layer (inner surface layer and outer surface layer) was changed. Table 1 shows the results of evaluation / judgment of the bottom crack of the multi-layer container, the butt-out test strength and the erecting stability.

[Comparative Example 1]
By changing the mold for blow molding, the biting support part has a length of 35 mm along the parting line, and has a height (L0) of 1.0 mm and a thickness (D) of 1.0 mm (L / L0). = 1.5, D / L0 = 1.0), and further container along the axial direction with reference to the point at which the two convex portions are located most inside the container along the axial direction of the bottom raised portion A synthetic resin blow-molded multi-layer similar to Example 1, except that the shape of the multi-layer container is changed so that its apex is not located inward (hereinafter sometimes referred to as “below the bottom raised portion”). A container was obtained. Table 1 shows the results of evaluation / judgment of the bottom crack of the multi-layer container, the butt-out test strength and the erecting stability.

[Comparative Example 2]
A synthetic resin blow molded multilayer container is obtained in the same manner as in Comparative Example 1 except that the composition of the surface layer (inner surface layer and outer surface layer) using LDPE2 is changed as the ethylene-based polyolefin resin forming the surface layer. It was. Table 1 shows the results of evaluation / judgment of the bottom crack of the multi-layer container, the butt-out test strength and the erecting stability.

  From Table 1, it is a synthetic resin blow-molded multilayer container that is provided with a mouth portion, a body portion, and a bottom portion in order along the axial direction of the container, and the multilayer container has at least an ethylene-based polyolefin resin (specifically, Comprises an inner surface layer containing low-density polyethylene), an intermediate layer having a barrier layer, and an outer surface layer containing an ethylene-based polyolefin resin (specifically, low-density polyethylene) in this order from the inside of the container. A) The bottom portion is surrounded by a circumferential grounding portion, and includes a planar bottom raising portion positioned inward of the container along the axial direction from the grounding portion; b) The bottom raising portion is a surface orthogonal to the axial direction of the bottom portion. A bottom seal portion extending substantially linearly from the bottom raised portion and extending outward from the container along the axial direction; c) the bottom seal portion i) an outer edge of the container along the axial direction; Is a circumferential grounding part A biting portion located inside the container along the vertical axis direction, and a biting support portion extending from the biting portion toward the inner side of the container along the axial direction and ending at the bottom raising portion, ii) The outer surface of the support portion is formed from the outer surface layer containing the ethylene-based polyolefin resin, and iii) the axis of the raised portion with respect to the maximum length L0 of the cross section along the axial direction of the biting support portion The ratio L / L0 of the length L of the cross section along the direction is in the range of 0.8 to 1.2; and d) raising the position corresponding to both ends of the bottom seal portion extending in a substantially straight line in the longitudinal direction A convex portion extending from the portion toward the inner side of the container along the axial direction and having the apex located further along the axial direction along the axial direction with reference to the point located most inside the container along the axial direction of the raised bottom portion Examples 1 and 2 characterized in that The direct blow molded multi-layer container made of synthetic resin has no crack at the bottom of the container, and the bottom resistance test strength is much larger than 10 kg. It was found that this was a synthetic resin blow molded multilayer container having excellent standing stability.

  On the other hand, in the bottom seal portion, the ratio L / L0 of the length L of the cross section along the axial direction of the bottom raised portion to the maximum length L0 of the cross section along the axial direction of the biting support portion is 0.8-1. Comparison that the convex part is not located in the range of 2 and the apex is located further inward of the container along the axial direction with reference to the point located most inside the container along the axial direction of the bottom raised part The synthetic resin blow-molded multilayer containers of Examples 1 and 2 have a bottom crack due to a drop test, and have a bottom resistance test strength of less than 10 kg, which may cause a bottom crack of the container and a swelling of the bottom. It was found that the container was evaluated as a synthetic resin blow molded multilayer container having no upright stability of the container.

The present invention is a blow molded multilayer container made of synthetic resin, which is sequentially provided with a mouth, a trunk and a bottom along the axial direction of the container,
The layer configuration of the multilayer container includes at least an inner surface layer containing an ethylene-based polyolefin resin, an intermediate layer having a barrier layer, and an outer surface layer containing an ethylene-based polyolefin resin in this order from the inside of the container.
a) The bottom portion is surrounded by a circumferential grounding portion, and includes a planar bottom raising portion positioned inward of the container along the axial direction from the grounding portion; b) The bottom raising portion is formed on a surface orthogonal to the axial direction of the bottom portion. Extending substantially linearly and connected to the bottom seal portion extending from the bottom raised portion toward the outside of the container along the axial direction; c) the bottom seal portion i) any of the outer surfaces; And ii) a biting portion in which the outer edge of the container along the axial direction is positioned inward of the container along the axial direction from the circumferential grounding portion, and the biting portion And a biting support portion extending toward the inside of the container along the axial direction and ending at the bottom raising portion, and iii) the bottom raising portion with respect to the maximum length L0 of the cross section along the axial direction of the biting support portion The ratio L / L0 of the length L of the cross section along the axial direction is 0.8. And d) extending from the bottom raised portion at a position corresponding to both ends of the bottom seal portion in a substantially linear shape to the inside of the container along the axial direction. A synthetic resin provided with the above-mentioned biting support portion, characterized in that it has a convex portion whose apex is further located inward of the container along the axial direction with reference to the point located most inward of the container along the axial direction of Provided is a blow molded multilayer container made of synthetic resin, particularly a direct blow molded multilayer container that can reliably maintain an upright posture of the container without causing a bottom crack of the container or swelling of the bottom by being a blow molded multilayer container. So that it can be used industrially.

1: mouth part 11: opening part 2: trunk part 3: bottom part 31: grounding part 32: bottom raising part 321, 321 ': convex part 33: bottom seal part 331: biting part 332: biting support part 331a, 331b: Pinch part 332a, 332b: Step part B: Barrier layer

Claims (7)

A synthetic resin blow-molded multilayer container comprising a mouth part, a body part and a bottom part in order along the axial direction of the container,
The synthetic resin blow molded multilayer container is formed by direct blow molding,
The synthetic resin blow-molded multilayer container has at least an inner surface layer containing an ethylene-based polyolefin resin, an intermediate layer having a barrier layer, and an outer surface layer containing an ethylene-based polyolefin resin from the inside of the container. In order,
a) said bottom is surrounded by circumferential ground portion includes a planar bottom raising portion located inside of the container along the axial direction from the ground portion;
b) the raised bottom portion, the extending in the plane perpendicular to the axial direction of the bottom portion substantially linearly, and connected to the bottom sealing portion extending toward the bottom raising portion outwardly of the container along the axial direction;
c) the bottom seal portion,
i) its the edge of the container outwardly along the axially-away eating located container inwardly along the axial direction from the grounding portion of the circumferential part, in a container along from the eating-away parts in the axial direction and a support portion outright eating ends with extension Mashimashi the raised bottom portion towards, in cross section along the direction in which the bottom seal portion extending substantially linearly, and the upper side and the lower side has a circular arc shape,
ii) Both the outer surface of the bite-away supporting portion is formed from the outer surface layer containing the pre disappeared styrene-based polyolefin resin, and,
iii) to the maximum length L0 of the cross section along the axial direction of the eating-away supporting portion, the ratio L / L0 is 0.8 to 1.2 range of the length L of the cross section along the axial direction of the raised bottom portion And; and
d) extending from each of the raised bottom portion of the position corresponding to the longitudinally opposite end portions extending in a substantially linear shape, one towards the inside of the container along the axial direction of the bottom sealing part, the said raised bottom portion have a two protrusions further its apex container inwardly along a point located on the most inside of the container along the axis direction in the axial direction as a reference position, the respective convex portion has a thickness and curvature The layer structure of the convex portion includes the intermediate layer having the barrier layer, the layer constituting the convex portion is bent, and the whole of the convex portions is the axis direction in the axial direction. Located on the bite ;
A blow molded multilayer container made of a synthetic resin comprising a bite-off support portion. The bottom sealing portion, iv) range to the maximum length L0 of the cross section along the axial direction of the eating-away supporting portion, the ratio D / L0 of the thickness D of the eating-away support portion 0.5-1.5 A synthetic resin blow-molded multilayer container comprising the bite-off support portion according to claim 1. The end face of the outermost of the container outwardly along the axial direction of the eating-away support portion, the cross section of the intermediate layer comprises a bite-away support part according to claim 1 or 2, wherein exposing with two said barrier layer Synthetic resin blow molded multilayer container. Ri sectional shape oval der perpendicular to the axial direction of said bottom,
Synthetic resin blow molding multilayer comprising a bite-away support part according to any one of claims 1 to 3 and the direction is substantially the same for the bottom sealing portion and the direction of the major axis of the ellipse extends substantially linearly container. A synthetic resin blow-molded multilayer container comprising the bite-off support portion according to any one of claims 1 to 4 , wherein the barrier layer is formed of an ethylene / vinyl alcohol copolymer. The intermediate layer, one or both the synthetic resin blow molding the multilayer container with a bite-away support part according to any one of claims 1 to 5 comprising an adhesive layer of the barrier layer. A blow molded multilayer container made of a synthetic resin comprising the bite-off support part according to any one of claims 1 to 6, comprising a recovery layer.

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