WO2020054710A1 - Direct blow-foamed container - Google Patents

Direct blow-foamed container Download PDF

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Publication number
WO2020054710A1
WO2020054710A1 PCT/JP2019/035529 JP2019035529W WO2020054710A1 WO 2020054710 A1 WO2020054710 A1 WO 2020054710A1 JP 2019035529 W JP2019035529 W JP 2019035529W WO 2020054710 A1 WO2020054710 A1 WO 2020054710A1
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WO
WIPO (PCT)
Prior art keywords
foaming
nozzle
nozzle portion
direct blow
blow
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PCT/JP2019/035529
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French (fr)
Japanese (ja)
Inventor
裕喜 飯野
市川　健太郎
山口　裕司
Original Assignee
東洋製罐グループホールディングス株式会社
メビウスパッケージング株式会社
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Application filed by 東洋製罐グループホールディングス株式会社, メビウスパッケージング株式会社 filed Critical 東洋製罐グループホールディングス株式会社
Publication of WO2020054710A1 publication Critical patent/WO2020054710A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
    • B29C49/02—Combined blow-moulding and manufacture of the preform or the parison
    • B29C49/04—Extrusion blow-moulding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D1/00—Containers having bodies formed in one piece, e.g. by casting metallic material, by moulding plastics, by blowing vitreous material, by throwing ceramic material, by moulding pulped fibrous material, by deep-drawing operations performed on sheet material
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent

Definitions

  • the present invention relates to a foam container obtained by direct blow molding.
  • plastic foam molded articles have excellent mechanical properties such as lightness and heat insulation, as well as rigidity, and are applied to various uses.
  • foaming by a so-called microcellular technique using an inert gas as a foaming agent.
  • inert gas as a foaming agent.
  • the foam cells become coarse.
  • the foam cells can be made to have a distribution, so that it can be applied to the field of packaging containers.
  • Patent Document 2 discloses that a foamable resin mixed with an inert gas as a foaming agent is melt-extruded. It has been proposed to subsequently form the container, ie a direct blow foam container, by blow molding.
  • foaming when foaming is applied to direct blow molding, there is a problem that foaming occurs even in a nozzle portion where a screw, a support ring, and the like are formed, which causes a problem such as a decrease in strength of the nozzle portion.
  • a preform for a container is molded by injection molding and a foaming technique is applied to a container obtained by blow molding the preform, a melt of a foaming resin containing a foaming agent (inert gas) is used. Since the filling is performed in the closed injection mold, foaming in the mold can be restricted by applying a holding pressure by overfilling the mold, so that foaming in the nozzle portion can be suppressed. .
  • the nozzle section has a lower draw ratio than the body section and is less susceptible to bubble compression due to blow air as in the case of the body section. If no special measures are taken, the bubble rate is lower than that of the body section. And it will be equal or higher.
  • a separately molded nozzle portion made of a non-foaming resin containing no foaming agent is fixed to the foaming container by means such as adhesion. Means can be employed. However, with such means, the container cannot be formed by one molding, and the production cost is increased.
  • an object of the present invention is to form a nozzle and a body connected thereto by direct blow molding without employing a means such as adhesion, and at the same time, foaming in the nozzle is effectively suppressed.
  • a direct blow foam container To provide a direct blow foam container.
  • the present inventors when producing a foam container by direct blow molding using a foaming resin containing a foaming agent, insert a blow nozzle into a blow mold, the clearance between the nozzle and the blow mold. By finely adjusting the pressure, the molding at the nozzle portion becomes a compression molding, thereby finding that the foaming at the nozzle portion can be effectively suppressed, thereby completing the present invention.
  • the nozzle portion and the body portion are integrally formed by direct blow molding using a foaming resin containing at least a foaming agent, and foam cells are distributed in the nozzle portion and the body portion.
  • a bubble rate at the nozzle portion is 70% or less of a bubble ratio at the body portion.
  • the bubble rate at the nozzle portion is 10% or less;
  • the outer surface of the container is a non-foamed outer layer formed of a non-foamed resin not containing a foaming agent, and the foamed cells are distributed on the inner surface side of the non-foamed outer layer. Layers are provided, (3) a non-foamed inner layer formed of the non-foamed resin is provided on the inner side of the foamed layer; (4)
  • the non-foaming resin the same thermoplastic resin as that used for forming the foaming resin is used; Is preferred.
  • the direct blow foam container of the present invention is formed integrally with the nozzle portion and the body portion by direct blow molding using a foaming resin containing a foaming agent, and does not separately mold the nozzle portion. Absent. Therefore, the productivity is high, and an increase in manufacturing cost can be avoided.
  • the most important feature of the present invention is that the bubble rate of the nozzle part is 70% of the bubble rate of the body part while the nozzle part is molded using a foaming resin containing a foaming agent similarly to the body part. The following is a significant reduction. That is, in the present invention, since the bubble ratio of the nozzle portion is greatly reduced as compared with the body portion, a decrease in strength due to foaming at the nozzle portion is effectively suppressed.
  • FIG. 2A is a schematic side cross-sectional view showing a distribution form of foam cells in a nozzle of the container of FIG. 1 and FIG.
  • FIG. 4 is a view for explaining means for suppressing foaming at a nozzle portion in the blowing step of FIG. 3.
  • FIG. 9 is a diagram illustrating a relationship between a nozzle portion compression ratio and a nozzle portion bubble ratio indicated by an experimental result in the first embodiment.
  • FIG. 9 is a diagram illustrating a relationship between a nozzle portion bubble rate and a nozzle portion compressive strength indicated by an experimental result in Example 1.
  • the direct blow foaming container of the present invention is indicated by reference numeral 10 as a whole, and has a nozzle portion 11 and a body portion 13 connected to the nozzle portion 11, and a lower end of the body portion 13 has a bottom portion. 15 has a closed configuration.
  • the nozzle portion 11 is not blown, and a projection 11a such as a thread for fixing a lid (not shown) such as a cap is formed on a straight outer surface.
  • a lid not shown
  • the trunk portion 13 is a blown portion and has a smooth outer surface which is swollen as a whole.
  • this foam container 10 is molded using a foaming resin containing a foaming agent, as shown in FIG. 20 are distributed.
  • foaming in the nozzle portion 11 is effectively suppressed, and the bubble rate (the existence ratio of the foam cells 20) in the nozzle portion 11 is 70% or less of the bubble rate in the body portion 13, In particular, it is suppressed to 50% or less.
  • This bubble rate is calculated from the specific gravity measured using a hydrometer.
  • a central region O 10 mm above the center portion Ho of the height H of the body portion 13 may be cut out, measured and calculated, and the bubble rate of the body portion 13 may be obtained.
  • the foaming of the nozzle portion 11 is largely suppressed as compared with the body portion 13, a reduction in the strength of the nozzle portion 11 is effectively avoided.
  • the bubble rate of the body portion 13 is usually in the range of about 10 to 30% from the viewpoint of securing advantages such as lightening and light-shielding properties by foaming without losing strength.
  • the foaming container 10 is manufactured by direct blow molding using a foaming resin containing a foaming agent.
  • this direct blow molding basically, as shown in FIG. 3, the foamable resin is melt-extruded to form a tubular parison 31, and the parison 31 is immediately cooled by a cooled blow mold.
  • the blow molds 33 and 33 are closed with the blow nozzle 35 inserted into the parison 31 and the bottom of the parison 31 is closed.
  • a surface 33a for forming the nozzle portion 11 is formed on the upper inner surface of the blow dies 33, 33, and a surface 33b for forming the body portion 13 is formed below the surface 33a.
  • a concave portion corresponding to the protrusion 11a in FIG. 1 is formed on the surface 33a for forming the nozzle portion 11.
  • the blow nozzle 35 is inserted into the parison 31, and a blow fluid such as air is supplied, whereby the blow fluid is shaped into the container 10 as shown in FIG. Foaming will take place.
  • the foamable resin is prepared by supplying a foaming agent to the thermoplastic resin melt-kneaded in the extruder.
  • thermoplastic resin various thermoplastic resins which can be directly blow-molded can be used.
  • various polyolefins and polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PNT), and polybutylene terephthalate (PBT) are preferably used,
  • PET polyethylene terephthalate
  • PNT polyethylene naphthalate
  • PBT polybutylene terephthalate
  • polyolefin is preferably used from the viewpoint of flexibility required for a direct blow container.
  • polyolefins include polyethylene such as low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), and linear ultra low density polyethylene (LVLDPE).
  • polypropylene, ethylene-propylene copolymer, polybutene-1, ethylene-butene-1 copolymer, propylene-butene-1 copolymer, ethylene-propylene-butene-1 copolymer, ethylene-vinyl acetate copolymer Coalescence, ion-crosslinked olefin copolymer (ionomer) and the like can be exemplified.
  • a polyolefin those having a so-called extrusion grade melt flow rate (MFR; ASTM-D-1238, 230 ° C.), for example, those having an MFR of 0.1 to 0.7 g / 10 min are preferably used. Is done.
  • the foaming agent to be mixed with the thermoplastic resin as described above a chemical foaming agent such as various carbonate compounds and azo compounds, and a physical foaming agent represented by an inert gas such as nitrogen and carbon dioxide are used.
  • an inert gas is preferably used from the viewpoint of controlling foaming.
  • the amount of the foaming agent supplied to the thermoplastic resin for direct blow molding in the molten state may be an amount such that an appropriate amount of foam cells is generated in the body portion 13 from melt extrusion to blow molding, and specifically, although it depends on the type, when nitrogen, which is an inert gas, is used as the blowing agent, the amount is preferably about 0.05 to 0.1 part by mass per 100 parts by mass of the resin.
  • foaming in the nozzle portion 11 must be suppressed as compared with the body portion 13.
  • a method of inserting the blow nozzle 35 into the parison 31 is adopted.
  • Such a technique is called a driving type.
  • a technique called a needle type in which the blow nozzle 35 is inserted into the parison 31 without inserting the blow nozzle 35 into the parison 31 and a blow fluid is introduced into the parison 31 to perform blow molding is known.
  • the needle type since the nozzle portion 11 is also shaped by the blow air, foaming cannot be suppressed effectively.
  • the tip portion of a blow nozzle 35 having a supply path of a blow fluid such as air has a straight outer surface 35a and a gradual flow toward the tip.
  • the blow nozzle 35 has a tapered outer surface 35b with a reduced diameter, and the blow nozzle 35 is arranged such that the straight outer surface 35a faces the upper inner surface 33a of the blow dies 33, 33 (the surface 33a for forming the nozzle portion 11).
  • a clearance CL is formed between the straight body portion 35a of the blow nozzle 35 and the inner surface 33a of the blow mold 33, and the size of the clearance CL is large.
  • the parison 31 is compression-molded, and the nozzle portion 11 is formed on the upper part of the parison 31, and the lower part expands and is thinned by the next blow. It will be shaped in the form of the trunk 13.
  • the clearance CL by finely adjusting the clearance CL to suppress foaming at the nozzle portion 11, foaming at the nozzle portion 11 is significantly suppressed as compared with the body portion 13.
  • the bubble rate can be set in a predetermined range. That is, at the time of melt extrusion, the inert gas in the resin or the gas generated by the decomposition of the foaming agent expands, and the resin is solidified by cooling by a blow mold. As a result, the foam cell 30 is generated.
  • a large compressive force can be applied by adjusting the clearance CL between the blow nozzle 35 and the inner surface 33a of the blow mold. That is, foaming at the surface can be suppressed.
  • the specific value of the clearance CL varies depending on the melt viscosity of the resin to be used and the amount of the foaming agent, and cannot be specified unconditionally. However, in general, the clearance CL and the thickness t of the parison 31 are different. It is preferable that the ratio CL / t is 0.5 or less, particularly 0.4 or less in order to set the bubble rate of the nozzle portion 11 in the above-described range.
  • direct blow molding is performed by a driving method.
  • the clearance CL between the straight body portion 35a of the blow nozzle 35 and the inner surface 33a of the blow mold 33 is reduced to the thickness of the parison 31.
  • the bubble rate in the nozzle portion 11 can be largely suppressed as compared with the body portion 13, thereby effectively preventing a decrease in the strength in the nozzle portion 11. be able to.
  • the foaming container 10 is formed by direct blow molding using a foaming resin in which a foaming agent is mixed, but in the present invention, a non-foaming resin containing no foaming agent is used in combination. Then, the foamed container 10 can be molded.
  • a non-foamed layer in which the foamed cells 20 are not distributed on the surface of the foamed layer in which the foamed cells 20 are distributed is used as a skin layer.
  • a skin layer is usually provided on the outer surface side of the foam layer, but can also be provided on the inner surface side of the foam layer. That is, in the present invention, the following layer structure can be adopted.
  • Container inner surface Foam layer / skin layer (non-foam layer): Container outer surface
  • Container inner surface Skin layer (non-foam layer) / foam layer / skin layer (non-foam layer): Container outer surface
  • Container inner surface Skin layer (Non-foamed layer) / foamed layer: outer surface of container
  • the formation of the skin layer as described above can effectively prevent the formation of surface irregularities due to foaming.
  • a skin layer is formed on the outer surface side of the container, the appearance of the container is prevented from deteriorating due to foaming, and the printing characteristics of the container can be enhanced.
  • the skin layer is provided on the outer surface side. Is most preferred.
  • the skin layer is provided on the inner surface side of the container, there is an advantage that the discharge property of the contents can be enhanced by the smoothness of the inner surface depending on the type of the contents of the container.
  • the non-foamable resin forming the skin layer as described above, it is preferable to use the resin used for the foamable resin forming the foamed layer. That is, by using such a resin, a layer structure in which both layers are firmly bonded can be secured without providing an adhesive layer or the like between the foam layer and the skin layer.
  • the thickness of the skin layer is not particularly limited.
  • the bubble ratio in the body 13 is maintained in the above range (10 to 30%). It is preferable to set the thickness of the skin layer such that Thereby, advantages such as appearance characteristics of the skin layer can be enjoyed without impairing the advantages of foaming.
  • the above-described direct blow container 10 of the present invention has a light weight and a high light-shielding property due to foaming, and also effectively avoids a decrease in the strength of the nozzle portion 11 due to foaming, and has high dimensional accuracy.
  • the present invention as described above is not limited to this, but takes advantage of the flexibility inherent in containers obtained by direct blow molding to make viscous contents such as cosmetics, liquid detergents, pharmaceuticals, and liquid seasonings. It is suitably applied to a container for storing materials and the like.
  • Example 1 A foamed bottle was produced using a blow mold and a blow mold having no uneven shape such as a screw or a support ring in a compression molding portion formed by a blow nozzle.
  • the clearance CL between the blow mold and the blow nozzle was kept constant at 1.3 mm, and CL / t was changed by setting the parison thickness t to 2.8 mm to 3.4 mm.
  • the thickness of the parison was changed by changing the clearance at the exit of the die while keeping the rotation speed of the extruder and the addition amount of the foaming agent constant.
  • the bubble ratio of the parison and the bottle nozzle before blowing and the compressive strength of the nozzle were measured for the produced bottle.
  • the specific gravity was measured using an electronic hydrometer (MDS-300, manufactured by Alpha Mirage Co., Ltd.), and was calculated by comparing the specific gravity of the non-foamed bottle.
  • MDS-300 manufactured by Alpha Mirage Co., Ltd.
  • For the compressive strength of the nozzle part cut out a range of 10 mm from the top of the nozzle part, apply a compressive load from the circumferential direction using a universal testing machine Tensilon (UCT-5T manufactured by Orientec), and measure the load when pressing down 4 mm did.
  • FIG. 5 is a graph showing the relationship between the compression ratio (the ratio CL / t between the mold clearance CL and the parison thickness t) at the nozzle portion and the bubble rate based on the experimental results.
  • FIG. 6 is a graph showing the relationship between the bubble ratio and the compression strength of the nozzle portion. It can be confirmed from FIG. 5 that the bubble rate decreases as the compression rate increases, and from FIG. 6, it can be confirmed that the lower the bubble rate, the higher the compression strength of the nozzle portion. For this reason, it can be said that suppressing the bubble rate of the nozzle portion is effective for fitting with the lid and suppressing overrun when tightening the screw.
  • Example 2 By adjusting the pressure at the time of blowing and changing the degree of compression of the bubbles, foamed bottles having different body bubble ratios were produced.
  • the produced bottle was compressed vertically by a universal testing machine Tensilon (UCT-5T, manufactured by Orientec), and the maximum load when the bottle buckled was measured as the longitudinal compressive strength.
  • Foaming direct blow container 11 Nozzle part 13: Body part 15: Bottom part 20: Foaming cell 31: Parison 33: Blow mold 35: Blow nozzle

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
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  • Health & Medical Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Ceramic Engineering (AREA)
  • Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
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Abstract

Provided is a direct blow-foamed container in which foaming in the nozzle portion is effectively curbed, while at the same time integrally forming a nozzle portion and body portion connected thereto by direct blow-molding, without using means such as adhesion. In addition, the present invention is a direct blow-foamed container 10 in which a nozzle portion 11 and a body portion 13 are integrally formed by direct blow-molding using a foaming resin which contains at least a foaming agent, and foam cells are distributed within the nozzle portion 11 and the body portion, characterized in that the foaming rate of the nozzle portion 11 does not exceed 70% of the foaming rate of the body portion 13.

Description

ダイレクトブロー発泡容器Direct blow foam container
　本発明は、ダイレクトブロー成形により得られた発泡容器に関する。 The present invention relates to a foam container obtained by direct blow molding.
　現在、プラスチックの発泡成形体は、軽量性、断熱性に優れ、さらには剛性等の機械的特性も高められており、種々の用途に適用されている。特に、最近では、不活性ガスを発泡剤として用いた物理発泡（所謂マイクロセルラー技術による発泡）によって微細な発泡セルを成形体の内部に形成し得るようになったため、その用途はさらに拡大し、例えば包装容器などの分野にも適用されるようになった（特許文献１参照）。即ち、炭酸ソーダやアゾ化合物などを発泡剤として使用し、発泡剤の熱分解により生成する炭酸ガスや窒素ガスなどで発泡させる所謂化学発泡では、発泡セルが粗大なものとなってしまい、この結果、発泡によるガスバリア性の低下、外観特性の低下、さらには強度の低下が著しくなってしまうため、包装容器の分野での使用が困難であったが、物理発泡では、発泡セルの大きさを微細にしたり、或いは発泡セルの大きさに分布を持たせることが可能となったため、包装容器の分野にも適用が可能となったものである。 Currently, plastic foam molded articles have excellent mechanical properties such as lightness and heat insulation, as well as rigidity, and are applied to various uses. In particular, recently, it has become possible to form fine foamed cells inside a molded body by physical foaming (foaming by a so-called microcellular technique) using an inert gas as a foaming agent. For example, it has come to be applied to fields such as packaging containers (see Patent Document 1). That is, in the so-called chemical foaming in which sodium carbonate, an azo compound, or the like is used as a foaming agent, and foaming is performed using carbon dioxide gas, nitrogen gas, or the like generated by thermal decomposition of the foaming agent, the foam cells become coarse. However, it is difficult to use in the field of packaging containers because the gas barrier property, the appearance characteristics, and the strength are significantly reduced due to foaming. Or the size of the foam cells can be made to have a distribution, so that it can be applied to the field of packaging containers.
　ところで、ダイレクトブロー成形により形成される容器についても上記の物理発泡の技術は検討されており、例えば特許文献２には、発泡剤である不活性ガスが混合されている発泡性樹脂を溶融押出し、引き続いてブロー成形にすることにより容器、即ち、ダイレクトブロー発泡容器を成形することが提案されている。 By the way, the technique of the physical foaming described above is also being studied for a container formed by direct blow molding. For example, Patent Document 2 discloses that a foamable resin mixed with an inert gas as a foaming agent is melt-extruded. It has been proposed to subsequently form the container, ie a direct blow foam container, by blow molding.
　しかしながら、ダイレクトブロー成形に発泡を適用した場合、螺子やサポートリング等が形成されるノズル部までもが発泡してしまい、ノズル部の強度低下などの問題を引き起こしてしまうことが問題となる。
　例えば、射出成形により容器用のプリフォームを成形し、このプリフォームをブロー成形することにより得られる容器に発泡技術を適用する時には、発泡剤（不活性ガス）を含む発泡性樹脂の溶融物が閉じられた射出金型内に充填されるため、金型への過充填により保圧をかけることによって金型内の発泡を制限することができるため、ノズル部での発泡を抑制することができる。しかし、ダイレクトブロー成形では、発泡剤を含む発泡性樹脂の溶融物が開放系に押し出されるため、押出時の発泡を抑制することができず、どうしてもノズル部を含む容器全体が発泡してしまい、ノズル部での発泡による強度低下を抑制することができない。特に、ノズル部は胴部と比較して延伸倍率が低い上、胴部のようにブローエアーによる気泡圧縮の影響を受けづらいため、特別な措置を講じない場合、その気泡率は胴部と比較して同等かそれ以上の値となってしまう。 However, when foaming is applied to direct blow molding, there is a problem that foaming occurs even in a nozzle portion where a screw, a support ring, and the like are formed, which causes a problem such as a decrease in strength of the nozzle portion.
For example, when a preform for a container is molded by injection molding and a foaming technique is applied to a container obtained by blow molding the preform, a melt of a foaming resin containing a foaming agent (inert gas) is used. Since the filling is performed in the closed injection mold, foaming in the mold can be restricted by applying a holding pressure by overfilling the mold, so that foaming in the nozzle portion can be suppressed. . However, in the direct blow molding, since the melt of the foaming resin containing a foaming agent is extruded into an open system, foaming at the time of extrusion cannot be suppressed, and the entire container including the nozzle part inevitably foams, The reduction in strength due to foaming at the nozzle cannot be suppressed. In particular, the nozzle section has a lower draw ratio than the body section and is less susceptible to bubble compression due to blow air as in the case of the body section.If no special measures are taken, the bubble rate is lower than that of the body section. And it will be equal or higher.
　また、ダイレクトブロー発泡容器におけるノズル部での発泡の問題を回避するためには、発泡剤を含まない非発泡性樹脂により別個成形されたノズル部を、接着等の手段により発泡容器に固定するという手段を採用することができる。しかしながら、このような手段では、一回の成形により容器を成形することができず、製造コストが高くなってしまう。 Further, in order to avoid the problem of foaming at the nozzle portion in the direct blow foaming container, a separately molded nozzle portion made of a non-foaming resin containing no foaming agent is fixed to the foaming container by means such as adhesion. Means can be employed. However, with such means, the container cannot be formed by one molding, and the production cost is increased.
特開２００８－０９４４９５号公報JP 2008-094495 A 特許第４７７８１４１号Patent No. 4778141
　従って、本発明の目的は、接着等の手段を採用することなく、ダイレクトブロー成形によりノズル部及びこれに連なる胴部が一体に成形されていると同時に、ノズル部での発泡が有効に抑制されているダイレクトブロー発泡容器を提供することにある。 Therefore, an object of the present invention is to form a nozzle and a body connected thereto by direct blow molding without employing a means such as adhesion, and at the same time, foaming in the nozzle is effectively suppressed. To provide a direct blow foam container.
　本発明者等は、発泡剤を含有する発泡性樹脂を用いてのダイレクトブロー成形により発泡容器を製造するに際し、ブローノズルをブロー金型内に挿入し、該ノズルとブロー金型とのクリアランスを微細に調整することにより、ノズル部での成形が圧縮成形となり、これにより、ノズル部での発泡を有効に抑制し得るという知見を見出し、本発明を完成させるに至った。 The present inventors, when producing a foam container by direct blow molding using a foaming resin containing a foaming agent, insert a blow nozzle into a blow mold, the clearance between the nozzle and the blow mold. By finely adjusting the pressure, the molding at the nozzle portion becomes a compression molding, thereby finding that the foaming at the nozzle portion can be effectively suppressed, thereby completing the present invention.
　本発明によれば、少なくとも発泡剤を含有する発泡性樹脂を用いてのダイレクトブロー成形によりノズル部と胴部とが一体に形成されており、且つ該ノズル部及び該胴部内に発泡セルが分布しているダイレクトブロー発泡容器において、前記ノズル部での気泡率が、前記胴部での気泡率の７０％以下であることを特徴とするダイレクトブロー発泡容器が提供される。 According to the present invention, the nozzle portion and the body portion are integrally formed by direct blow molding using a foaming resin containing at least a foaming agent, and foam cells are distributed in the nozzle portion and the body portion. In the direct blow foaming container, a bubble rate at the nozzle portion is 70% or less of a bubble ratio at the body portion.
　本発明のダイレクトブロー発泡容器においては、
（１）前記ノズル部での気泡率が１０％以下であること、
（２）前記容器の外面は、発泡剤を含有していない非発泡樹脂により形成された非発泡外面層となっており、該非発泡外面層の内面側に、前記発泡セルが分布している発泡層が設けられていること、
（３）前記発泡層の内面側に、前記非発泡樹脂により形成された非発泡内面層が設けられていること、
（４）前記非発泡樹脂として、前記発泡性樹脂の形成に使用されているものと同種の熱可塑性樹脂が使用されていること、
が好適である。 In the direct blow foam container of the present invention,
(1) The bubble rate at the nozzle portion is 10% or less;
(2) The outer surface of the container is a non-foamed outer layer formed of a non-foamed resin not containing a foaming agent, and the foamed cells are distributed on the inner surface side of the non-foamed outer layer. Layers are provided,
(3) a non-foamed inner layer formed of the non-foamed resin is provided on the inner side of the foamed layer;
(4) As the non-foaming resin, the same thermoplastic resin as that used for forming the foaming resin is used;
Is preferred.
　本発明のダイレクトブロー発泡容器は、発泡剤を含有する発泡性樹脂を用いてのダイレクトブロー成形によりノズル部と胴部と一体に形成されているものであり、ノズル部を別個に成形するものではない。このため、生産性が高く、製造コストの増大を回避することができる。
　しかも、本発明の最も重要な特徴は、ノズル部も、胴部と同様、発泡剤を含む発泡性樹脂を用いて成形されていながら、ノズル部の気泡率が、胴部の気泡率の７０％以下に大きく低減されていることにある。即ち、本発明では、ノズル部の気泡率が胴部に比して大きく低減されていることから、ノズル部での発泡による強度低下が有効に抑制されている。 The direct blow foam container of the present invention is formed integrally with the nozzle portion and the body portion by direct blow molding using a foaming resin containing a foaming agent, and does not separately mold the nozzle portion. Absent. Therefore, the productivity is high, and an increase in manufacturing cost can be avoided.
In addition, the most important feature of the present invention is that the bubble rate of the nozzle part is 70% of the bubble rate of the body part while the nozzle part is molded using a foaming resin containing a foaming agent similarly to the body part. The following is a significant reduction. That is, in the present invention, since the bubble ratio of the nozzle portion is greatly reduced as compared with the body portion, a decrease in strength due to foaming at the nozzle portion is effectively suppressed.
本発明のダイレクトブロー発泡容器の全体の形態を示す概略図。The schematic diagram showing the whole form of the direct blow foam container of the present invention. 図１の容器のノズルでの発泡セルの分布形態を示す概略側断面図（ａ）及び胴部での発泡セルの分布形態を示す概略側断面図（ｂ）。FIG. 2A is a schematic side cross-sectional view showing a distribution form of foam cells in a nozzle of the container of FIG. 1 and FIG. 本発明のダイレクトブロー発泡容器を成形するためのブロー工程を説明するための図。The figure for demonstrating the blow process for shape | molding the direct blow foam container of this invention. 図３のブロー工程において、ノズル部での発泡を抑制するための手段を説明するための図。FIG. 4 is a view for explaining means for suppressing foaming at a nozzle portion in the blowing step of FIG. 3. 実施例１における実験結果が示すノズル部圧縮率とノズル部気泡率との関係を示す図。FIG. 9 is a diagram illustrating a relationship between a nozzle portion compression ratio and a nozzle portion bubble ratio indicated by an experimental result in the first embodiment. 実施例１における実験結果が示すノズル部気泡率とノズル部圧縮強度との関係を示す図。FIG. 9 is a diagram illustrating a relationship between a nozzle portion bubble rate and a nozzle portion compressive strength indicated by an experimental result in Example 1. 実施例２における実験結果が示す胴部気泡率とボトル縦圧縮強度との関係を示す図。The figure which shows the relationship between the foam | bubble ratio of the trunk | drum shown by the experimental result in Example 2, and a bottle longitudinal compression strength.
　図１において、本発明のダイレクトブロー発泡容器は、全体として１０で示されており、ノズル部１１と、ノズル部１１に連なる胴部１３とを有しており、胴部１３の下端は、底部１５によって閉じられた形態を有している。 In FIG. 1, the direct blow foaming container of the present invention is indicated by reference numeral 10 as a whole, and has a nozzle portion 11 and a body portion 13 connected to the nozzle portion 11, and a lower end of the body portion 13 has a bottom portion. 15 has a closed configuration.
　図１から理解されるように、ノズル部１１は、ブローされておらず、ストレートな外面に、キャップ等の蓋体（図示せず）を固定するための螺条等の突起１１ａが形成されている。一方、胴部１３は、ブローされた部分であり、全体として膨らんだ滑らかな外面を有している。 As can be understood from FIG. 1, the nozzle portion 11 is not blown, and a projection 11a such as a thread for fixing a lid (not shown) such as a cap is formed on a straight outer surface. I have. On the other hand, the trunk portion 13 is a blown portion and has a smooth outer surface which is swollen as a whole.
　本発明において、この発泡容器１０は、発泡剤を含む発泡性樹脂を用いて成形されているため、図２に示されているように、ノズル部１１及び胴部１３内の何れにも発泡セル２０が分布している。 In the present invention, since this foam container 10 is molded using a foaming resin containing a foaming agent, as shown in FIG. 20 are distributed.
　しかるに、本発明では、ノズル部１１での発泡が有効に抑制されており、このノズル部１１での気泡率（発泡セル２０の存在割合）が、胴部１３での気泡率の７０％以下、特に５０％以下に抑制されている。
　この気泡率は、比重計を使用して測定される比重より算出される。特に胴部１３では、胴部１３のハイトＨの中心部分Ｈｏから上１０ｍｍの中心部領域Ｏを切り出して、測定および計算して胴部１３の気泡率とすればよい。 However, in the present invention, foaming in the nozzle portion 11 is effectively suppressed, and the bubble rate (the existence ratio of the foam cells 20) in the nozzle portion 11 is 70% or less of the bubble rate in the body portion 13, In particular, it is suppressed to 50% or less.
This bubble rate is calculated from the specific gravity measured using a hydrometer. In particular, in the case of the body portion 13, a central region O 10 mm above the center portion Ho of the height H of the body portion 13 may be cut out, measured and calculated, and the bubble rate of the body portion 13 may be obtained.
　即ち、本発明では、ノズル部１１の発泡が、胴部１３に比して、大きく抑制されているため、ノズル部１１の強度低下を有効に回避されている。
　また、胴部１３の気泡率は、強度を損なわずに、発泡による軽量化、遮光性等の利点を確保するという観点から、通常、１０～３０％程度の範囲にあることが好適である。 That is, in the present invention, since the foaming of the nozzle portion 11 is largely suppressed as compared with the body portion 13, a reduction in the strength of the nozzle portion 11 is effectively avoided.
In addition, it is preferable that the bubble rate of the body portion 13 is usually in the range of about 10 to 30% from the viewpoint of securing advantages such as lightening and light-shielding properties by foaming without losing strength.
＜ダイレクトブロー発泡容器１０の製造＞
　本発明において、上記の発泡容器１０は、発泡剤を含む発泡性樹脂を用いてのダイレクトブロー成形により製造される。
　このダイレクトブロー成形は、基本的に、図３に示されているように、上記の発泡性樹脂を溶融押出してチューブ状のパリソン３１を成形し、このパリソン３１を直ちに、冷却されているブロー型３３，３３内に移動させ、パリソン３１内にブローノズル３５を挿入した状態でブロー型３３，３３を閉じ、パリソン３１の底部を閉じる。このとき、ブロー型３３，３３の上部内面には、ノズル部１１形成用の面３３ａが形成されており、その下方には、胴部１３形成用の面３３ｂが形成されている。
　尚、ノズル部１１形成用の面３３ａには、図３では省略されているが、図１における突起１１ａに対応する凹部が形成されている。 <Manufacture of direct blow foam container 10>
In the present invention, the foaming container 10 is manufactured by direct blow molding using a foaming resin containing a foaming agent.
In this direct blow molding, basically, as shown in FIG. 3, the foamable resin is melt-extruded to form a tubular parison 31, and the parison 31 is immediately cooled by a cooled blow mold. The blow molds 33 and 33 are closed with the blow nozzle 35 inserted into the parison 31 and the bottom of the parison 31 is closed. At this time, a surface 33a for forming the nozzle portion 11 is formed on the upper inner surface of the blow dies 33, 33, and a surface 33b for forming the body portion 13 is formed below the surface 33a.
Although not shown in FIG. 3, a concave portion corresponding to the protrusion 11a in FIG. 1 is formed on the surface 33a for forming the nozzle portion 11.
　上記の状態で、パリソン３１内にブローノズル３５を挿入し、エア等のブロー流体が供給され、これにより、図１に示されているような容器１０の形態に賦形され、この過程で、発泡が行われることとなる。 In the above state, the blow nozzle 35 is inserted into the parison 31, and a blow fluid such as air is supplied, whereby the blow fluid is shaped into the container 10 as shown in FIG. Foaming will take place.
　本発明において、発泡性樹脂は、押出機内で溶融混練されている熱可塑性樹脂に発泡剤を供給することにより調製される。 に お い て In the present invention, the foamable resin is prepared by supplying a foaming agent to the thermoplastic resin melt-kneaded in the extruder.
　上記の熱可塑性樹脂としては、ダイレクトブロー成形が可能な種々の熱可塑性樹脂を使用することができる。一般的には、これに限定されるものではないが、各種ポリオレフィンや、ポリエチレンテレフタレート（ＰＥＴ）、ポリエチレンナフタレート（ＰＮＴ）、ポリブチレンテレフタレート（ＰＢＴ）等のポリエステルなどが好適に使用されるが、特にダイレクトブロー容器に要求される柔軟性などの観点から、ポリオレフィンが好適に使用される。
　このようなポリオレフィンとしては、例えば低密度ポリエチレン（ＬＤＰＥ）、中密度ポリエチレン（ＭＤＰＥ）、高密度ポリエチレン（ＨＤＰＥ）、線状低密度ポリエチレン（ＬＬＤＰＥ）、線状超低密度ポリエチレン（ＬＶＬＤＰＥ）等のポリエチレンや、ポリプロピレン、エチレン－プロピレン共重合体、ポリブテン－１、エチレン－ブテン－１共重合体、プロピレン－ブテン－１共重合体、エチレン－プロピレン－ブテン－１共重合体、エチレン－酢酸ビニル共重合体、イオン架橋オレフィン共重合体（アイオノマー）等を例示することができる。このようなポリオレフィンとしては、所謂押出グレードのメルトフローレート（ＭＦＲ；ＡＳＴＭ－Ｄ－１２３８，２３０℃）を有するもの、例えば、０．１～０．７ｇ／１０ｍｉｎのＭＦＲを有するものが好適に使用される。 As the above-mentioned thermoplastic resin, various thermoplastic resins which can be directly blow-molded can be used. Generally, although not limited thereto, various polyolefins and polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PNT), and polybutylene terephthalate (PBT) are preferably used, In particular, polyolefin is preferably used from the viewpoint of flexibility required for a direct blow container.
Examples of such polyolefins include polyethylene such as low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), and linear ultra low density polyethylene (LVLDPE). Or polypropylene, ethylene-propylene copolymer, polybutene-1, ethylene-butene-1 copolymer, propylene-butene-1 copolymer, ethylene-propylene-butene-1 copolymer, ethylene-vinyl acetate copolymer Coalescence, ion-crosslinked olefin copolymer (ionomer) and the like can be exemplified. As such a polyolefin, those having a so-called extrusion grade melt flow rate (MFR; ASTM-D-1238, 230 ° C.), for example, those having an MFR of 0.1 to 0.7 g / 10 min are preferably used. Is done.
　また、上記のような熱可塑性樹脂に混合される発泡剤としては、各種炭酸化合物やアゾ化合物などの化学発泡剤や、窒素、二酸化炭素等の不活性ガスに代表される物理発泡剤を使用することができるが、特に発泡をコントロールするという観点から、不活性ガスが好適に使用される。
　溶融状態のダイレクトブロー成形用熱可塑性樹脂に供給する発泡剤量は、溶融押出からブロー成形にかけて、胴部１３に適度な量の発泡セルが生成する程度の量であればよく、具体的には、その種類によっても異なるが、不活性ガスである窒素を発泡剤として用いる場合には樹脂１００質量部当り、０．０５～０．１質量部程度の量とすることが好適である。 As the foaming agent to be mixed with the thermoplastic resin as described above, a chemical foaming agent such as various carbonate compounds and azo compounds, and a physical foaming agent represented by an inert gas such as nitrogen and carbon dioxide are used. In particular, an inert gas is preferably used from the viewpoint of controlling foaming.
The amount of the foaming agent supplied to the thermoplastic resin for direct blow molding in the molten state may be an amount such that an appropriate amount of foam cells is generated in the body portion 13 from melt extrusion to blow molding, and specifically, Although it depends on the type, when nitrogen, which is an inert gas, is used as the blowing agent, the amount is preferably about 0.05 to 0.1 part by mass per 100 parts by mass of the resin.
　ところで、本発明においては、胴部１３に比して、ノズル部１１での発泡を抑制しなければならない。このために、先に述べたように、パリソン３１内にブローノズル３５を挿入するという手法が採用される。このような手法は、打込み式と呼ばれている。例えば、ブローノズル３５をパリソン３１内に挿入せず、パリソン３１の上部から針状のブローノズル３５を挿入し、パリソン３１内にブロー流体を導入してブロー成形を行うニードル式と呼ばれる手法が知られているが、ニードル式では、ノズル部１１もブローエアーにより賦形されることとなるため、有効に発泡を抑制することができない。 By the way, in the present invention, foaming in the nozzle portion 11 must be suppressed as compared with the body portion 13. For this purpose, as described above, a method of inserting the blow nozzle 35 into the parison 31 is adopted. Such a technique is called a driving type. For example, a technique called a needle type in which the blow nozzle 35 is inserted into the parison 31 without inserting the blow nozzle 35 into the parison 31 and a blow fluid is introduced into the parison 31 to perform blow molding is known. However, in the needle type, since the nozzle portion 11 is also shaped by the blow air, foaming cannot be suppressed effectively.
　本発明で採用する打込み式によるブロー方式を説明する図４を参照すると、エア等のブロー流体の供給路を有するブローノズル３５の先端部分は、ストレートな直胴外面３５ａと、先端に行くに従い漸次縮径したテーパー外面３５ｂとを有しているが、この直胴外面３５ａが、ブロー型３３，３３の上部内面３３ａ（ノズル部１１形成用の面３３ａ）に対面するように、ブローノズル３５が挿入されている。
　この図４から理解されるように、このような打込み式では、ブローノズル３５の直胴部３５ａとブロー型３３の内面３３ａとの間にクリアランスＣＬが形成されており、このクリアランスＣＬの大きさにしたがって、ブロー型３３，３３を閉じたときにパリソン３１が圧縮成形され、パリソン３１の上部にノズル部１１が形成されることとなり、次のブローによって、その下方が膨張し、薄肉化されて胴部１３の形態に賦形されることとなる。 Referring to FIG. 4 illustrating a blow-in type blow method adopted in the present invention, the tip portion of a blow nozzle 35 having a supply path of a blow fluid such as air has a straight outer surface 35a and a gradual flow toward the tip. The blow nozzle 35 has a tapered outer surface 35b with a reduced diameter, and the blow nozzle 35 is arranged such that the straight outer surface 35a faces the upper inner surface 33a of the blow dies 33, 33 (the surface 33a for forming the nozzle portion 11). Has been inserted.
As can be understood from FIG. 4, in such a driving method, a clearance CL is formed between the straight body portion 35a of the blow nozzle 35 and the inner surface 33a of the blow mold 33, and the size of the clearance CL is large. Accordingly, when the blow molds 33, 33 are closed, the parison 31 is compression-molded, and the nozzle portion 11 is formed on the upper part of the parison 31, and the lower part expands and is thinned by the next blow. It will be shaped in the form of the trunk 13.
　本発明では、上記のクリアランスＣＬを微細に調節することにより、ノズル部１１での発泡を抑制することで、ノズル部１１での発泡を胴部１３に比して大きく抑制し、ノズル部１１の気泡率を所定の範囲に設定することができる。即ち、溶融押出に際して、樹脂中の不活性ガスもしくは発泡剤の分解により生じたガスが膨張し、ブロー型による冷却によって樹脂が固化し、この結果として、発泡セル３０が生成するのであるが、上記のノズル部１１では、ブローノズル３５とブロー型の内面３３ａとのクリアランスＣＬの調整により、大きな圧縮力を印加することができ、このような圧縮力によって、ガスの膨張を制限し、ノズル部１１での発泡を抑制することができるわけである。 In the present invention, by finely adjusting the clearance CL to suppress foaming at the nozzle portion 11, foaming at the nozzle portion 11 is significantly suppressed as compared with the body portion 13. The bubble rate can be set in a predetermined range. That is, at the time of melt extrusion, the inert gas in the resin or the gas generated by the decomposition of the foaming agent expands, and the resin is solidified by cooling by a blow mold. As a result, the foam cell 30 is generated. In the nozzle section 11, a large compressive force can be applied by adjusting the clearance CL between the blow nozzle 35 and the inner surface 33a of the blow mold. That is, foaming at the surface can be suppressed.
　例えば、溶融押出により形成されるパリソン３１の厚みｔに際して、クリアランスＣＬが小さい程、ノズル部１１には大きな圧縮力が加わることとなり、発泡を大きく抑制することができる。 For example, when the thickness t of the parison 31 formed by melt extrusion is increased, the smaller the clearance CL is, the greater the compressive force is applied to the nozzle portion 11, and the foaming can be largely suppressed.
　上記のクリアランスＣＬの具体的な数値は、用いる樹脂の溶融粘度や発泡剤量によっても異なり、一概に規定することはできないが、一般的には、上記のクリアランスＣＬとパリソン３１の厚みｔとの比ＣＬ／ｔが０．５以下、特に０．４以下にあることが、ノズル部１１の気泡率を前述した範囲に設定する上で好適である。 The specific value of the clearance CL varies depending on the melt viscosity of the resin to be used and the amount of the foaming agent, and cannot be specified unconditionally. However, in general, the clearance CL and the thickness t of the parison 31 are different. It is preferable that the ratio CL / t is 0.5 or less, particularly 0.4 or less in order to set the bubble rate of the nozzle portion 11 in the above-described range.
　このように、本発明においては、打込み式によりダイレクトブロー成形を行い、この際に、ブローノズル３５の直胴部３５ａとブロー型３３の内面３３ａとの間のクリアランスＣＬを、パリソン３１の厚みに応じて微細な範囲に設定しておくことにより、胴部１３に比してノズル部１１での気泡率が大きく抑制することができ、これにより、ノズル部１１での強度低下を有効に回避することができる。 As described above, in the present invention, direct blow molding is performed by a driving method. At this time, the clearance CL between the straight body portion 35a of the blow nozzle 35 and the inner surface 33a of the blow mold 33 is reduced to the thickness of the parison 31. By setting it to a fine range, the bubble rate in the nozzle portion 11 can be largely suppressed as compared with the body portion 13, thereby effectively preventing a decrease in the strength in the nozzle portion 11. be able to.
　上述した本発明において、発泡剤が混合されている発泡性樹脂を用いてダイレクトブロー成形により発泡容器１０が成形されているが、本発明では、発泡剤を含有していない非発泡性樹脂を併用して発泡容器１０を成形することもできる。 In the above-described present invention, the foaming container 10 is formed by direct blow molding using a foaming resin in which a foaming agent is mixed, but in the present invention, a non-foaming resin containing no foaming agent is used in combination. Then, the foamed container 10 can be molded.
　具体的には、発泡性樹脂と非発泡性樹脂とを用いての共押出により、発泡セル２０が分布している発泡層の表面に発泡セル２０が分布していない非発泡層をスキン層として設けることができる。このようなスキン層は、通常、発泡層の外面側に設けられるが、発泡層の内面側にも設けることもできる。
　即ち、本発明では、以下の層構造を採用することができる。
　　　容器内面側：発泡層／スキン層（非発泡層）：容器外面側
　　　容器内面側：スキン層（非発泡層）／発泡層／スキン層（非発泡
　　　層）：容器外面側
　　　容器内面側：スキン層（非発泡層）／発泡層：容器外面側 Specifically, by co-extrusion using a foamable resin and a non-foamable resin, a non-foamed layer in which the foamed cells 20 are not distributed on the surface of the foamed layer in which the foamed cells 20 are distributed is used as a skin layer. Can be provided. Such a skin layer is usually provided on the outer surface side of the foam layer, but can also be provided on the inner surface side of the foam layer.
That is, in the present invention, the following layer structure can be adopted.
Container inner surface: Foam layer / skin layer (non-foam layer): Container outer surface Container inner surface: Skin layer (non-foam layer) / foam layer / skin layer (non-foam layer): Container outer surface Container inner surface: Skin layer (Non-foamed layer) / foamed layer: outer surface of container
　本発明においては、上記のようなスキン層の形成により、発泡による表面凹凸の形成を有効に回避することができる。例えば、容器の外面側にスキン層が形成されているときには、発泡による容器の外観低下を回避し、また、容器の印刷特性を高めることができ、本発明では、外面側にスキン層を設けることが最も好適である。また、容器の内面側にスキン層を設けた場合には、容器内容物の種類によっては、内面の平滑性により、内容物の排出性を高めることができるという利点がある。 In the present invention, the formation of the skin layer as described above can effectively prevent the formation of surface irregularities due to foaming. For example, when a skin layer is formed on the outer surface side of the container, the appearance of the container is prevented from deteriorating due to foaming, and the printing characteristics of the container can be enhanced. In the present invention, the skin layer is provided on the outer surface side. Is most preferred. Further, when the skin layer is provided on the inner surface side of the container, there is an advantage that the discharge property of the contents can be enhanced by the smoothness of the inner surface depending on the type of the contents of the container.
　本発明において、上記のようなスキン層を形成する非発泡性樹脂としては、発泡層を形成している発泡性樹脂に使用されている樹脂を使用することが好ましい。即ち、このような樹脂を使用することにより、発泡層とスキン層との間に接着剤層などを設けることなく、両層が強固に接着した層構造を確保することができる。 に お い て In the present invention, as the non-foamable resin forming the skin layer as described above, it is preferable to use the resin used for the foamable resin forming the foamed layer. That is, by using such a resin, a layer structure in which both layers are firmly bonded can be secured without providing an adhesive layer or the like between the foam layer and the skin layer.
　また、本発明において、上記のスキン層の厚みは特に制限されるものではないが、発泡の利点を確保するため、胴部１３での気泡率が前述した範囲（１０～３０％）に維持されるようにスキン層の厚みを設定することが好ましい。これにより、発泡の利点を損なうことなく、スキン層による外観特性等の利点を享受することができる。 In the present invention, the thickness of the skin layer is not particularly limited. However, in order to secure the advantage of foaming, the bubble ratio in the body 13 is maintained in the above range (10 to 30%). It is preferable to set the thickness of the skin layer such that Thereby, advantages such as appearance characteristics of the skin layer can be enjoyed without impairing the advantages of foaming.
　上述した本発明のダイレクトブロー容器１０は、発泡による軽量化や高い遮光性を有しており、しかも、発泡によるノズル部１１の強度低下を有効に回避されており、さらに寸法精度も高い。このような本発明は、これに限定されるものではないが、ダイレクトブロー成形により得られる容器に特有の柔軟性を活かして、粘稠な内容物、例えば化粧液、液体洗剤、医薬品、液体調味料等を収容する容器に好適に適用される。 The above-described direct blow container 10 of the present invention has a light weight and a high light-shielding property due to foaming, and also effectively avoids a decrease in the strength of the nozzle portion 11 due to foaming, and has high dimensional accuracy. The present invention as described above is not limited to this, but takes advantage of the flexibility inherent in containers obtained by direct blow molding to make viscous contents such as cosmetics, liquid detergents, pharmaceuticals, and liquid seasonings. It is suitably applied to a container for storing materials and the like.
　本発明を次の実験例で説明する。 The present invention will be described with reference to the following experimental examples.
（実施例１）
　ブロー金型とブローノズルによる圧縮成形部に螺子やサポートリング等の凹凸形状を有さないブロー金型を用いて、発泡ボトルの作製を行った。この際、ブロー金型とブローノズルのクリアランスＣＬは１．３ｍｍで一定とし、パリソン厚みｔを２．８ｍｍ～３．４ｍｍとすることでＣＬ／ｔを変化させた。尚、パリソン厚みの変更に際しては、押出機の回転数および発泡剤の添加量は一定のまま、ダイ出口部分のクリアランスを変更することで実施した。 (Example 1)
A foamed bottle was produced using a blow mold and a blow mold having no uneven shape such as a screw or a support ring in a compression molding portion formed by a blow nozzle. At this time, the clearance CL between the blow mold and the blow nozzle was kept constant at 1.3 mm, and CL / t was changed by setting the parison thickness t to 2.8 mm to 3.4 mm. The thickness of the parison was changed by changing the clearance at the exit of the die while keeping the rotation speed of the extruder and the addition amount of the foaming agent constant.
　作製したボトルについてブロー前のパリソンおよびボトルノズル部の気泡率とノズル部の圧縮強度を測定した。
　気泡率の測定には電子比重計（アルファミラージュ社製　ＭＤＳ－３００）を用いて比重を測定し、非発泡ボトルの比重と比較して算出した。
　ノズル部の圧縮強度は、ノズル部天面から１０ｍｍの範囲を切出し、万能試験機テンシロン（オリエンテック社製　ＵＣＴ－５Ｔ）を用い、周方向から圧縮荷重を付加し、４ｍｍ押下時の荷重を測定した。 The bubble ratio of the parison and the bottle nozzle before blowing and the compressive strength of the nozzle were measured for the produced bottle.
The specific gravity was measured using an electronic hydrometer (MDS-300, manufactured by Alpha Mirage Co., Ltd.), and was calculated by comparing the specific gravity of the non-foamed bottle.
For the compressive strength of the nozzle part, cut out a range of 10 mm from the top of the nozzle part, apply a compressive load from the circumferential direction using a universal testing machine Tensilon (UCT-5T manufactured by Orientec), and measure the load when pressing down 4 mm did.
　実験結果を表１に示す。また、この実験結果に基づいて、ノズル部における圧縮率（金型クリアランスＣＬとパリソン厚みｔとの比ＣＬ／ｔ）と気泡率の関係を図５のグラフに示す。また、気泡率とノズル部の圧縮強度の関係を図６のグラフには示す。
　図５より圧縮率が大きくなるほど気泡率が低下することが確認でき、図６より気泡率が低いほうがノズル部の圧縮強度が強いことが確認できる。このため、ノズル部の気泡率を抑えることは、蓋との勘合性や、螺子を締める際のオーバーラン抑制などに効果的であると言える。 Table 1 shows the experimental results. FIG. 5 is a graph showing the relationship between the compression ratio (the ratio CL / t between the mold clearance CL and the parison thickness t) at the nozzle portion and the bubble rate based on the experimental results. FIG. 6 is a graph showing the relationship between the bubble ratio and the compression strength of the nozzle portion.
It can be confirmed from FIG. 5 that the bubble rate decreases as the compression rate increases, and from FIG. 6, it can be confirmed that the lower the bubble rate, the higher the compression strength of the nozzle portion. For this reason, it can be said that suppressing the bubble rate of the nozzle portion is effective for fitting with the lid and suppressing overrun when tightening the screw.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
（実施例２）
　ブロー時の圧力を調整し、気泡の圧縮度合いを変化させることで、胴部気泡率の異なる発泡ボトルを作製した。
　作製したボトルを万能試験機テンシロン（オリエンテック社製　ＵＣＴ－５Ｔ）により垂直方向に圧縮し、ボトルが座屈する際の最大荷重を縦圧縮強度として測定した。 (Example 2)
By adjusting the pressure at the time of blowing and changing the degree of compression of the bubbles, foamed bottles having different body bubble ratios were produced.
The produced bottle was compressed vertically by a universal testing machine Tensilon (UCT-5T, manufactured by Orientec), and the maximum load when the bottle buckled was measured as the longitudinal compressive strength.
　実験結果を図７に示す。
　図７より、気泡率の増加に伴い縦圧縮強度が向上することが確認できる。特に気泡率１０％以上で非発泡と比較して顕著な強度向上効果が見られる。このため、強度向上や軽量化の効果を得るためには胴部の気泡率を高くすることが有効であるといえる。 The experimental results are shown in FIG.
From FIG. 7, it can be confirmed that the longitudinal compressive strength is improved as the bubble rate increases. In particular, when the bubble ratio is 10% or more, a remarkable effect of improving the strength is observed as compared with non-foaming. For this reason, it can be said that it is effective to increase the bubble ratio of the body in order to obtain the effect of improving the strength and reducing the weight.
　実施例１および実施例２より、ノズル部の強度向上にはノズル部の気泡率を低くする必要があり、ボトルの縦圧縮強度には胴部の気泡率を高くする必要があるといった、相反する特徴を１つのボトル内に付与することの重要性が示された。本発明のように、ノズル部と胴部とに気泡率分布を持たせることで、ノズル部強度とボトル縦圧縮強度を高いレベルで両立することが可能となる。 From Examples 1 and 2, there is a contradiction that it is necessary to reduce the bubble rate of the nozzle part to improve the strength of the nozzle part, and to increase the bubble rate of the body part to the longitudinal compression strength of the bottle. The importance of providing features in one bottle was shown. By providing a bubble rate distribution in the nozzle portion and the body portion as in the present invention, it is possible to achieve both high nozzle portion strength and high bottle longitudinal compression strength.
　　１０：発泡ダイレクトブロー容器
　　１１：ノズル部
　　１３：胴部
　　１５：底部
　　２０：発泡セル
　　３１：パリソン
　　３３：ブロー型
　　３５：ブローノズル 10: Foaming direct blow container 11: Nozzle part 13: Body part 15: Bottom part 20: Foaming cell 31: Parison 33: Blow mold 35: Blow nozzle

Claims (5)

  1. 　少なくとも発泡剤を含有する発泡性樹脂を用いてのダイレクトブロー成形によりノズル部と胴部とが一体に形成されており、且つ該ノズル部及び該胴部内に発泡セルが分布しているダイレクトブロー発泡容器において、
    　前記ノズル部での気泡率が、前記胴部での気泡率の７０％以下であることを特徴とするダイレクトブロー発泡容器。     Direct blow foaming in which a nozzle portion and a body portion are integrally formed by direct blow molding using a foaming resin containing at least a foaming agent, and foam cells are distributed in the nozzle portion and the body portion. In the container,
    A direct blow foam container, wherein a bubble rate in the nozzle portion is 70% or less of a bubble ratio in the body portion.
  2. 　前記ノズル部での気泡率が１０％以下である請求項１に記載のダイレクトブロー発泡容器。 ダ イ レ ク ト The direct blow foam container according to claim 1, wherein a bubble ratio in the nozzle portion is 10% or less.
  3. 　前記容器の外面は、発泡剤を含有していない非発泡樹脂により形成された非発泡外面層となっており、該非発泡外面層の内面側に、前記発泡セルが分布している発泡層が設けられている請求項１に記載のダイレクトブロー発泡容器。 The outer surface of the container is a non-foamed outer layer formed of a non-foamed resin that does not contain a foaming agent, and a foamed layer in which the foam cells are distributed is provided on the inner surface side of the non-foamed outer layer. The direct blow foam container according to claim 1, wherein
  4. 　前記発泡層の内面側に、前記非発泡樹脂により形成された非発泡内面層が設けられている請求項３に記載のダイレクトブロー発泡容器。 4. The direct blow foam container according to claim 3, wherein a non-foamed inner surface layer formed of the non-foamed resin is provided on an inner surface side of the foamed layer.
  5. 　前記非発泡樹脂として、前記発泡性樹脂の形成に使用されているものと同種の熱可塑性樹脂が使用されている請求項３に記載のダイレクトブロー発泡容器。 4. The direct blow foam container according to claim 3, wherein the non-foamable resin is the same type of thermoplastic resin as that used for forming the foamable resin.
PCT/JP2019/035529 2018-09-13 2019-09-10 Direct blow-foamed container WO2020054710A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001527106A (en) * 1997-12-19 2001-12-25 トレクセル・インコーポレーテッド Extrusion / blow molding process for microporous foam and products produced thereby
JP2010274958A (en) * 2009-05-28 2010-12-09 Yoshino Kogyosho Co Ltd Vessel
JP2013095050A (en) * 2011-10-31 2013-05-20 Toyo Seikan Kaisha Ltd Formed resin molded product
JP2013100491A (en) * 2011-10-17 2013-05-23 Japan Polypropylene Corp Polypropylene-based resin composition and foamed molding
WO2013118718A1 (en) * 2012-02-07 2013-08-15 東洋製罐グループホールディングス株式会社 Vapour deposition foam

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001527106A (en) * 1997-12-19 2001-12-25 トレクセル・インコーポレーテッド Extrusion / blow molding process for microporous foam and products produced thereby
JP2010274958A (en) * 2009-05-28 2010-12-09 Yoshino Kogyosho Co Ltd Vessel
JP2013100491A (en) * 2011-10-17 2013-05-23 Japan Polypropylene Corp Polypropylene-based resin composition and foamed molding
JP2013095050A (en) * 2011-10-31 2013-05-20 Toyo Seikan Kaisha Ltd Formed resin molded product
WO2013118718A1 (en) * 2012-02-07 2013-08-15 東洋製罐グループホールディングス株式会社 Vapour deposition foam

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