JP2006137058A - Manufacturing method of plastic bottle container - Google Patents

Manufacturing method of plastic bottle container Download PDF

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Publication number
JP2006137058A
JP2006137058A JP2004327636A JP2004327636A JP2006137058A JP 2006137058 A JP2006137058 A JP 2006137058A JP 2004327636 A JP2004327636 A JP 2004327636A JP 2004327636 A JP2004327636 A JP 2004327636A JP 2006137058 A JP2006137058 A JP 2006137058A
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Prior art keywords
preform
bottle container
stretching
plastic bottle
thickness
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JP4734896B2 (en
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Masaki Miura
正樹 三浦
Koji Maeda
耕二 前田
Hidehiko Katsuta
秀彦 勝田
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Toyo Seikan Group Holdings Ltd
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Toyo Seikan Kaisha Ltd
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00Indexing scheme relating to blow-moulding
    • B29C2949/07Preforms or parisons characterised by their configuration
    • B29C2949/081Specified dimensions, e.g. values or ranges
    • B29C2949/0811Wall thickness
    • B29C2949/0813Wall thickness of the neck
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00Indexing scheme relating to blow-moulding
    • B29C2949/07Preforms or parisons characterised by their configuration
    • B29C2949/081Specified dimensions, e.g. values or ranges
    • B29C2949/082Diameter
    • B29C2949/0826Diameter of the body
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00Indexing scheme relating to blow-moulding
    • B29C2949/07Preforms or parisons characterised by their configuration
    • B29C2949/081Specified dimensions, e.g. values or ranges
    • B29C2949/0829Height, length
    • B29C2949/0835Height, length of the body
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00Indexing scheme relating to blow-moulding
    • B29C2949/20Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer
    • B29C2949/22Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer at neck portion
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00Indexing scheme relating to blow-moulding
    • B29C2949/20Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer
    • B29C2949/24Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer at flange portion
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00Indexing scheme relating to blow-moulding
    • B29C2949/20Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer
    • B29C2949/26Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer at body portion
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00Indexing scheme relating to blow-moulding
    • B29C2949/20Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer
    • B29C2949/28Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer at bottom portion
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00Indexing scheme relating to blow-moulding
    • B29C2949/30Preforms or parisons made of several components
    • B29C2949/3008Preforms or parisons made of several components at neck portion
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00Indexing scheme relating to blow-moulding
    • B29C2949/30Preforms or parisons made of several components
    • B29C2949/3012Preforms or parisons made of several components at flange portion
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00Indexing scheme relating to blow-moulding
    • B29C2949/30Preforms or parisons made of several components
    • B29C2949/3016Preforms or parisons made of several components at body portion
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00Indexing scheme relating to blow-moulding
    • B29C2949/30Preforms or parisons made of several components
    • B29C2949/302Preforms or parisons made of several components at bottom portion
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00Indexing scheme relating to blow-moulding
    • B29C2949/30Preforms or parisons made of several components
    • B29C2949/3024Preforms or parisons made of several components characterised by the number of components or by the manufacturing technique
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00Indexing scheme relating to blow-moulding
    • B29C2949/30Preforms or parisons made of several components
    • B29C2949/3024Preforms or parisons made of several components characterised by the number of components or by the manufacturing technique
    • B29C2949/3026Preforms or parisons made of several components characterised by the number of components or by the manufacturing technique having two or more components
    • B29C2949/3028Preforms or parisons made of several components characterised by the number of components or by the manufacturing technique having two or more components having three or more components
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00Indexing scheme relating to blow-moulding
    • B29C2949/30Preforms or parisons made of several components
    • B29C2949/3024Preforms or parisons made of several components characterised by the number of components or by the manufacturing technique
    • B29C2949/3026Preforms or parisons made of several components characterised by the number of components or by the manufacturing technique having two or more components
    • B29C2949/3028Preforms or parisons made of several components characterised by the number of components or by the manufacturing technique having two or more components having three or more components
    • B29C2949/303Preforms or parisons made of several components characterised by the number of components or by the manufacturing technique having two or more components having three or more components having more than three components
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00Indexing scheme relating to blow-moulding
    • B29C2949/30Preforms or parisons made of several components
    • B29C2949/3032Preforms or parisons made of several components having components being injected
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00Indexing scheme relating to blow-moulding
    • B29C2949/30Preforms or parisons made of several components
    • B29C2949/3032Preforms or parisons made of several components having components being injected
    • B29C2949/3034Preforms or parisons made of several components having components being injected having two or more components being injected
    • B29C2949/3036Preforms or parisons made of several components having components being injected having two or more components being injected having three or more components being injected
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00Indexing scheme relating to blow-moulding
    • B29C2949/30Preforms or parisons made of several components
    • B29C2949/3032Preforms or parisons made of several components having components being injected
    • B29C2949/3034Preforms or parisons made of several components having components being injected having two or more components being injected
    • B29C2949/3036Preforms or parisons made of several components having components being injected having two or more components being injected having three or more components being injected
    • B29C2949/3038Preforms or parisons made of several components having components being injected having two or more components being injected having three or more components being injected having more than three components being injected
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00Indexing scheme relating to blow-moulding
    • B29C2949/30Preforms or parisons made of several components
    • B29C2949/3041Preforms or parisons made of several components having components being extruded
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00Indexing scheme relating to blow-moulding
    • B29C2949/30Preforms or parisons made of several components
    • B29C2949/3041Preforms or parisons made of several components having components being extruded
    • B29C2949/3042Preforms or parisons made of several components having components being extruded having two or more components being extruded
    • B29C2949/3044Preforms or parisons made of several components having components being extruded having two or more components being extruded having three or more components being extruded
    • B29C2949/3046Preforms or parisons made of several components having components being extruded having two or more components being extruded having three or more components being extruded having more than three components being extruded

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  • Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a plastic bottle container made thin-walled uniformly as a whole by uniformly and sufficiently stretching a preform as a whole by preventing the whitening caused by over-stretching or local stretching at the time of stretch blowing of the preform. <P>SOLUTION: In a stretch blow molding method for forming the plastic bottle container by heating the bottomed cylindrical preform to a predetermined temperature to subject the same to stretch blow molding, blow air is supplied under heating and pressure to hold the preform to a softened state suitable for stretching at a region where the over-stretching or local stretching of the preform in a stretching process is easy to occur and the preform is reasonably stretched to prevent the whitening caused by over-stretching or local stretching to be stretched uniformly and sufficiently as a whole. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、ポリエチレンテレフタレート等からなるプリフォーム(パリソン)を延伸ブロー成形してプラスチックボトル容器を製造するにあたり、過延伸による白化や、局部的な延伸を防止して、プリフォーム全体を均一かつ十分に延伸することができ、これによってボトル容器の全体を均一に薄肉化できるプラスチックボトル容器の製造方法に関する。   In the present invention, when a preform (parison) made of polyethylene terephthalate or the like is stretch blow molded to produce a plastic bottle container, whitening due to overstretching and local stretching are prevented, and the entire preform is uniform and sufficient. The present invention relates to a method for producing a plastic bottle container, which can be stretched in a uniform manner, whereby the entire bottle container can be uniformly thinned.

一般に、ポリエチレンテレフタレート等のポリエステル、ポリプロピレン、ポリアミド等からなり、延伸ブローによって成形されるプラスチックボトル容器が知られている。この種のプラスチックボトル容器は、一般に、射出成形されたプリフォーム(パリソン)を延伸ブロー成形することにより製造される(例えば、特許文献1、特許文献2等)。
このように延伸ブロー成形方法により製造されたプラスチックボトル容器は、透明性とガスバリヤー性に優れ、飲料水、ミネラルウォーター、ミルクコーヒー、茶類、健康飲料、酒類、調味料等のボトル容器として広く使用されている。
In general, a plastic bottle container made of polyester such as polyethylene terephthalate, polypropylene, polyamide or the like and formed by stretch blow is known. This type of plastic bottle container is generally manufactured by subjecting an injection-molded preform (parison) to stretch blow molding (for example, Patent Document 1, Patent Document 2, etc.).
Thus, the plastic bottle container manufactured by the stretch blow molding method has excellent transparency and gas barrier properties, and is widely used as a bottle container for drinking water, mineral water, milk coffee, teas, health drinks, alcoholic beverages, seasonings, etc. in use.

特開2002−240136号公報(第4頁、第4図)JP 2002-240136 A (page 4, FIG. 4) 特許公報第3011058号公報(第2頁)Japanese Patent Publication No. 3011058 (Page 2)

ところで、近年、プラスチックボトル容器は急速に普及、浸透するようになり、この広範な普及にともない、特に飲料用の容器に対して、容器の薄肉化、軽量化が強く要請されるようになった。例えば、現在、容量2000ml用の容器として使用されているプラスチックボトル容器は平均肉厚が約0.35mm程度あるが、これを更に薄肉化したいという要請がある。
ここで、プラスチックボトル容器の肉厚は、プリフォームの樹脂量を削減し、高い延伸倍率で延伸ブロー成形することにより薄肉化が可能である。
By the way, in recent years, plastic bottle containers have rapidly spread and penetrated, and with this wide spread, there has been a strong demand for thinner and lighter containers, especially for beverage containers. . For example, a plastic bottle container currently used as a container for a capacity of 2000 ml has an average wall thickness of about 0.35 mm, but there is a demand for further reducing the thickness.
Here, the thickness of the plastic bottle container can be reduced by reducing the resin amount of the preform and performing stretch blow molding at a high stretch ratio.

しかし、このように単にプリフォームの樹脂量を減らして延伸倍率を高める方法では、過延伸による白化や、破裂などの問題や、均一な肉厚分布のボトルが得られ難いという問題があった。
特に、特許文献1や特許文献2にあるような角形ボトル容器にあっては、周方向ではコーナー部、高さ方向では肩部、及びヒール部において、プリフォームの延伸量が比較的多くなる。このため、相対的に厚肉になり易い胴部の側面の肉厚を減らそうとして、単純にプリフォームの肉厚を薄くしたり、延伸倍率を高くしたりしただけでは、コーナー部などでの延伸倍率が局部的に高くなり、これに伴って肉厚が薄くなり過ぎてしまい、過延伸による白化や局部的な延伸などの問題が顕著になってしまう。
However, such a method of simply reducing the amount of resin in the preform and increasing the draw ratio has problems such as whitening due to overstretching, rupture and the like, and it is difficult to obtain a bottle with a uniform wall thickness distribution.
In particular, in the rectangular bottle container as described in Patent Document 1 or Patent Document 2, the amount of the preform stretched is relatively large in the corner portion in the circumferential direction, and in the shoulder portion and heel portion in the height direction. For this reason, simply reducing the thickness of the preform or increasing the draw ratio in order to reduce the thickness of the side of the body, which tends to be relatively thick, The stretch ratio is locally increased, and accordingly, the wall thickness is too thin, and problems such as whitening due to overstretching and local stretching become remarkable.

すなわち、プリフォームを延伸ブローするに際し、ブローエアによる横方向の膨張・延伸をみてみると、プリフォームは、ほぼ同心円状に延伸されるため、角形ボトル容器を成形する場合には、容器側面に相当する部位が延伸を終えた後、さらにコーナー部に相当する部分が延伸される。このため、角形ボトル容器のコーナー部は高延伸になり易く、容器の薄肉化を図って対向する容器側面間の距離のみを考慮してプリフォームの径や肉厚などを設計すると、コーナー部に過度の延伸が及ぼされ、特に、コーナー部の延伸は、延伸ブロー工程の後期に、延伸過程にあるプリフォームが常温ブローエアにより冷却され、固化がある程度進んだ状態から行われるため、温度が低い状態での無理な過延伸になり易い。
また、ブローエアとストレッチロッドによる縦方向の延伸をみてみると、先ずストレッチロッドによりノズル下とヒール部に相当する部分が先に延伸され、その後に中央部分(胴部)が、ストレッチロッドとブローエアにより延伸されるため、ノズル下とヒール部は高延伸になり易く、また、局部的な延伸が生じ易い。
このため、横方向と縦方向とで、ともに高延伸になり易い容器の肩部の対角方向と、ヒール部の対角方向において、常温のブローエアでは比較的冷えた状態のプリフォームを無理に延伸するため、過延伸による白化や、局部的な延伸などが顕著に生じてしまう。
In other words, when the preform is stretched and blown, when looking at the expansion and stretching in the lateral direction by the blow air, the preform is stretched almost concentrically, so when forming a square bottle container, it corresponds to the side of the container After the portion to be stretched has been stretched, the portion corresponding to the corner portion is further stretched. For this reason, the corner part of a square bottle container tends to be highly stretched, and if the diameter and thickness of the preform are designed in consideration of only the distance between the opposing container side surfaces by reducing the thickness of the container, Excessive stretching, especially in the corners, is performed at a low temperature because the preform in the stretching process is cooled by room temperature blow air and solidified to some extent in the later stage of the stretching blow process. It is easy to become overstretched at.
Also, when looking at the longitudinal stretching with blow air and stretch rod, the stretch rod first stretches the part corresponding to the bottom of the nozzle and the heel part first, and then the central part (body part) is stretched by the stretch rod and blow air. Since it is stretched, the bottom of the nozzle and the heel portion are likely to be highly stretched, and local stretching is likely to occur.
For this reason, it is impossible to force a preform that is relatively cold with blow air at room temperature in the diagonal direction of the shoulder portion of the container and the diagonal direction of the heel portion, both of which are likely to be highly stretched in both the horizontal and vertical directions. Since the film is stretched, whitening due to overstretching, local stretching, or the like occurs remarkably.

本発明は、以上のような従来の技術が有する問題を解決するために提案されたものであり、プリフォームを延伸ブローするに際し、延伸過程にあるプリフォームを延伸に適した状態に維持させ、プリフォームの延伸が無理なくなされるようにすることで、過延伸による白化や、局部的な延伸を防止してプリフォーム全体を均一かつ十分に延伸することができ、これによって、ボトル全体を均一に薄肉化できるプラスチックボトル容器の提供を目的とする。   The present invention has been proposed in order to solve the problems of the conventional techniques as described above. When the preform is stretch-blown, the preform in the stretching process is maintained in a state suitable for stretching. By making it easy to stretch the preform, it is possible to uniformly and sufficiently stretch the entire preform by preventing whitening due to overstretching and local stretching, thereby making the entire bottle uniform. The purpose is to provide a plastic bottle container that can be made thinner.

本発明のプラスチックボトル容器の製造方法は、有底筒状のプリフォームを所定温度で加熱し、延伸ブロー成形することにより、プラスチックボトル容器を製造する方法であって、前記プリフォームを延伸ブローするブローエアを加熱加圧供給して、延伸過程にある前記プリフォームが、延伸に適した軟化状態を維持するようにした構成としてある。
このような構成とすることにより、過延伸や局部的な延伸が生じ易い部位においても延伸に適した状態を維持させ、無理なく延伸がなされるようにすることができ、過延伸による白化や、局部的な延伸を生じることなく、全体が均一に薄肉化されたプラスチックボトル容器を良好に製造することができる。
The method for producing a plastic bottle container of the present invention is a method for producing a plastic bottle container by heating a bottomed cylindrical preform at a predetermined temperature and performing stretch blow molding, wherein the preform is stretch blown. Blow air is supplied under heating and pressure so that the preform in the stretching process maintains a softened state suitable for stretching.
By adopting such a configuration, it is possible to maintain a state suitable for stretching even in a region where overstretching and local stretching are likely to occur, and it is possible to perform stretching without difficulty, whitening due to overstretching, Without causing local stretching, it is possible to satisfactorily manufacture a plastic bottle container that is thinned uniformly throughout.

このとき、前記ブローエアは、プリフォームを構成する材料や、プリフォームを容器形態に延伸する際の延伸倍率などを考慮して、70〜180℃の温度範囲で加熱供給するのが好ましく、また、延伸速度や、ブローエアの設定温度などを考慮して、2〜4MPaの圧力範囲で加圧供給するのが好ましい。
また、延伸ブローを行うに先だって、前記プリフォームは、110〜120℃の温度に加熱するのが好ましい。この加熱条件とブローエアの温度設定とを適宜組み合わせることにより、樹脂の粘性を落とし、延伸成形で発生する歪みや過延伸による白化を抑制することができる。
At this time, the blow air is preferably supplied by heating in a temperature range of 70 to 180 ° C. in consideration of the material constituting the preform, the draw ratio when the preform is drawn into a container form, In consideration of the stretching speed, the set temperature of the blow air, etc., it is preferable to pressurize in a pressure range of 2 to 4 MPa.
Moreover, it is preferable that the preform is heated to a temperature of 110 to 120 ° C. prior to stretching blow. By appropriately combining this heating condition and the temperature setting of the blow air, it is possible to reduce the viscosity of the resin, and to suppress whitening due to distortion or overstretching that occurs in stretch molding.

さらに、本発明に係るプラスチックボトル容器の製造方法にあっては、前記プリフォームの胴部と底部の間に段付部を形成することにより、容器底部の軽量化を図りつつ、前記段付部と前記底部を一体的に延伸させるようにすることで、プリフォームの胴部及び底部の連続する所定範囲を均一に延伸することができる。また、前記プリフォームの口部と胴部の間に、前記胴部より肉薄のストレート部及び径が絞り込まれながら肉厚を徐々に増して前記ストレート部と前記胴部とを接続する絞り部を有する首下部を形成することにより、前記首下部を前記胴部と一体的に延伸させるようにすることで、プリフォームの胴部及び口部の連続する所定範囲を均一に延伸することができる。その結果、プリフォームの全体が均一に延伸されるようにすることができる。   Further, in the method for manufacturing a plastic bottle container according to the present invention, the stepped portion is formed while reducing the weight of the container bottom by forming a stepped portion between the body portion and the bottom portion of the preform. By extending the bottom part and the bottom part integrally, it is possible to uniformly stretch a predetermined range of the body part and the bottom part of the preform. Further, between the mouth portion and the trunk portion of the preform, a straight portion that is thinner than the trunk portion and a throttle portion that gradually increases the thickness while the diameter is narrowed and connects the straight portion and the trunk portion. By forming the neck lower portion, the neck lower portion is extended integrally with the body portion, so that a predetermined range of the preform body portion and the mouth portion can be uniformly extended. As a result, the entire preform can be stretched uniformly.

以上のような本発明のプラスチックボトル容器の延伸ブロー成形方法によれば、プリフォームを延伸ブローするブローエアを加熱加圧供給して、延伸過程にあるプリフォームが、延伸に適した軟化状態に維持されるようにしたことで、過延伸や局部的な延伸が生じ易い部位においても延伸に適した状態を維持させ、無理なく延伸がなされるようにすることができる。これにより、過延伸による白化や、局部的な延伸を生じることなく、ボトル全体を均一に薄肉化でき、例えば、平均肉厚が約0.22mm程度以下の所望の薄肉ボトルを得ることができる。   According to the stretch blow molding method of the plastic bottle container of the present invention as described above, the blow air for stretching and blowing the preform is heated and pressurized to maintain the preform in the stretching process in a softened state suitable for stretching. By doing so, it is possible to maintain a state suitable for stretching even in a region where overstretching or local stretching is likely to occur, and to perform stretching without difficulty. Accordingly, the entire bottle can be uniformly thinned without causing whitening due to overstretching or local stretching, and for example, a desired thin-walled bottle having an average wall thickness of about 0.22 mm or less can be obtained.

以下、本発明に係るプラスチックボトル容器の製造方法の好ましい実施形態について、図面を参照しつつ説明する。
図1は、本発明に係るプラスチックボトル容器の製造方法の一実施形態において使用されるプリフォームの概略を示す断面図である。図2は、図1に示すプリフォームの要部拡大図で、(a)は首下部付近の拡大図、(b)は段付部付近の拡大図である。図3は、本発明に係るプラスチックボトル容器の製造方法の一実施形態における製造工程の概略を示す工程図である。
Hereinafter, a preferred embodiment of a method for producing a plastic bottle container according to the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view schematically showing a preform used in an embodiment of a method for producing a plastic bottle container according to the present invention. 2A and 2B are enlarged views of the main part of the preform shown in FIG. 1, wherein FIG. 2A is an enlarged view of the vicinity of the lower part of the neck, and FIG. FIG. 3 is a process diagram showing an outline of a production process in an embodiment of the method for producing a plastic bottle container according to the present invention.

[プリフォーム]
1.プリフォームの構造
図1に示すように、本実施形態で使用するプリフォーム1は、ボトル容器10(図4参照)を製造するための予備成形品であって、熱可塑性樹脂からなり、筒状の胴部4と、胴部4の一端側に開口する口部2と、胴部4の他端側を閉塞するほぼ半球形状の底部5を備えた有底筒状(試験管状)に形成されている。
そして、プリフォーム1は、胴部4と底部5の間に所定形状に形成された段付部5aを備え、また、口部2と胴部4の間に所定形状に形成された首下部3を備えている。
[preform]
1. As shown in FIG. 1, a preform 1 used in the present embodiment is a preform for producing a bottle container 10 (see FIG. 4), and is made of a thermoplastic resin and has a cylindrical shape. Body portion 4, a mouth portion 2 that opens to one end side of the body portion 4, and a substantially hemispherical bottom portion 5 that closes the other end side of the body portion 4. ing.
The preform 1 includes a stepped portion 5 a formed in a predetermined shape between the body portion 4 and the bottom portion 5, and a neck lower portion 3 formed in a predetermined shape between the mouth portion 2 and the body portion 4. It has.

段付部5aは、胴部4と底部5の間に位置するプリフォーム1の一部(所定範囲)であり、胴部4からほぼ同じ肉厚で連続し、内面及び外面がともに筒中心側に傾斜しつつ底部5に連続するように形成されている。
ここで、段付部5aは、肉厚、内面及び外面の傾斜角度、長さ等を所望の値に設定することができ、製造しようとするボトル容器の大きさ、形状、肉厚等に応じて任意に設定可能である。
The stepped portion 5a is a part (predetermined range) of the preform 1 located between the barrel portion 4 and the bottom portion 5 and is continuous from the barrel portion 4 with substantially the same thickness. Both the inner surface and the outer surface are on the cylinder center side. It is formed so as to continue to the bottom 5 while inclining.
Here, the stepped portion 5a can set the wall thickness, the inclination angle of the inner and outer surfaces, the length, etc. to desired values, depending on the size, shape, wall thickness, etc. of the bottle container to be manufactured. Can be set arbitrarily.

本実施形態では、図2に示す胴部4の肉厚Taと段付部5aと底部5の境界部の肉厚Tbの比が、1.0<Ta/Tb≦1.5となるように設定してある。
このような範囲に設定するのは、胴部4より段付部5aの肉厚が大きくなる(Ta/Tb≦1.0)ようにプリフォーム1を射出成形することは困難であり、また、Ta/Tbが1.5を超えると(Ta/Tb>1.5)、胴部4と段付部5aの肉厚差が大きくなり過ぎ、胴部4と段付部5aの連続部分に局部延伸、過延伸が生じる傾向が強くなるためである。なお、段付部5aの肉厚Tbとは、底部5と段付部5aの境界部の厚みをいう(図2(b)参照)。
In the present embodiment, the ratio of the thickness Ta of the body 4 shown in FIG. 2 to the thickness Tb of the boundary between the stepped portion 5a and the bottom 5 is 1.0 <Ta / Tb ≦ 1.5. It is set.
Setting such a range makes it difficult to injection-mold the preform 1 so that the thickness of the stepped portion 5a is larger than that of the body portion 4 (Ta / Tb ≦ 1.0). When Ta / Tb exceeds 1.5 (Ta / Tb> 1.5), the difference in thickness between the body 4 and the stepped portion 5a becomes too large, and the local portion is continuously formed between the body 4 and the stepped portion 5a. This is because stretching and overstretching tend to occur. The thickness Tb of the stepped portion 5a refers to the thickness of the boundary portion between the bottom portion 5 and the stepped portion 5a (see FIG. 2B).

また、図2に示す胴部4の筒中心から肉厚中心までの半径Raと、段付部5aと底部5の境界部における筒中心から肉厚中心までの半径Rbと、胴部4の肉厚Taとが、Rb≦Ra−Ta/2となるように設定してある。
このような範囲に設定するのは、段付部5aの半径は少なくとも胴部4の半径より小さくしなければ段差が形成されず、その一方、半径の差が胴部4の肉厚Taの半分以下の段差は、射出成形が困難となるためである。
以上のような値に設定することにより、段付き部5aを連続する胴部4とほぼ同じ肉厚にしつつ所望の角度に傾斜させることができる。
2, the radius Ra from the cylinder center to the thickness center of the barrel portion 4, the radius Rb from the cylinder center to the thickness center at the boundary between the stepped portion 5 a and the bottom portion 5, and the thickness of the barrel portion 4. The thickness Ta is set to satisfy Rb ≦ Ra−Ta / 2.
The range is set so that a step is not formed unless the radius of the stepped portion 5a is at least smaller than the radius of the body portion 4, while the difference in radius is half the thickness Ta of the body portion 4. The following steps are because injection molding becomes difficult.
By setting the values as described above, the stepped portion 5a can be inclined at a desired angle while making the stepped portion 5a substantially the same thickness as the continuous body portion 4.

さらに、図2(b)に示す段付部5aの筒中心側に傾斜する角度θは、所望の範囲に設定可能である。段付部5aの傾斜角度を設定することにより、角度に応じて段付部5a及び底部5の延伸量及び底部5の重量を制御することができる。
すなわち、段付部5aの傾斜角度θを小さくなるように設定すれば、段付部5aの延伸量が大きくなり、底部5の延伸量が小さくなって、底部5の重量が大きくなる。一方、段付部5aの傾斜角度θを大きくなるように設定すれば、段付部5aの延伸量が小さくなり、底部5の延伸量が大きくなって、底部5の重量は小さくすることができる。
Furthermore, the angle θ inclined toward the cylinder center side of the stepped portion 5a shown in FIG. 2B can be set in a desired range. By setting the inclination angle of the stepped portion 5a, the extension amount of the stepped portion 5a and the bottom portion 5 and the weight of the bottom portion 5 can be controlled according to the angle.
That is, if the inclination angle θ of the stepped portion 5a is set to be small, the stretch amount of the stepped portion 5a increases, the stretch amount of the bottom portion 5 decreases, and the weight of the bottom portion 5 increases. On the other hand, if the inclination angle θ of the stepped portion 5a is set to be large, the stretch amount of the stepped portion 5a is reduced, the stretch amount of the bottom portion 5 is increased, and the weight of the bottom portion 5 can be reduced. .

ここで、段付部5aの傾斜角度θとしては、7°≦θ≦45°とするのが好ましく、特に20°≦θ≦40°の範囲で設定することが好ましい。段付部5aの傾斜角度θが7°より小さいと(θ<7°)、段差による効果が得られず、また、45°より大きいと(θ>45°)、局部延伸、過延伸が生じる傾向が強くなるためである。   Here, the inclination angle θ of the stepped portion 5a is preferably 7 ° ≦ θ ≦ 45 °, and particularly preferably set in the range of 20 ° ≦ θ ≦ 40 °. If the inclination angle θ of the stepped portion 5a is smaller than 7 ° (θ <7 °), the effect due to the step cannot be obtained, and if it is larger than 45 ° (θ> 45 °), local stretching and overstretching occur. This is because the tendency becomes stronger.

なお、図2に示す例では、段付部5aの内面と外面はほぼ同じ角度に傾斜しており、段付部5aの肉厚が胴部4から底部5までほぼ同じ値となるように設定してあるが、この段付部5aの傾斜角度は、内面と外面で異ならせるようにしても良い。このようにすると、例えば、段付部5aの外面の傾斜角度を内面の傾斜角度より大きく設定することで、段付部5aを胴部4から底部5に向かって肉薄になるテーパ形状に形成することができ、所望の肉薄部分を設定して延伸量を大きくすることができる。
そして、このような段付部5aを備えることにより、後述する工程によりプリフォーム1が延伸ブロー成形されると、段付部5a及び底部5が全体的に均一に延伸され、胴部4の延伸負担を小さくして、また、底部5の重量を少なくして、結果的にプリフォーム全体が均一に延伸されるようになる。
In the example shown in FIG. 2, the inner surface and the outer surface of the stepped portion 5 a are inclined at substantially the same angle, and the thickness of the stepped portion 5 a is set to be substantially the same value from the body portion 4 to the bottom portion 5. However, the inclination angle of the stepped portion 5a may be different between the inner surface and the outer surface. If it does in this way, the stepped part 5a is formed in the taper shape which becomes thin toward the bottom part 5 from the trunk | drum 4 by setting the inclination angle of the outer surface of the stepped part 5a larger than the inclination angle of an inner surface, for example. It is possible to increase the stretch amount by setting a desired thin portion.
And by providing such a stepped part 5a, when the preform 1 is stretch blow-molded by a process described later, the stepped part 5a and the bottom part 5 are stretched uniformly uniformly, and the body part 4 is stretched. The burden is reduced and the weight of the bottom 5 is reduced, and as a result, the entire preform is stretched uniformly.

首下部3は、胴部4と口部2の間に位置するプリフォーム1の一部(所定範囲)であり、口部2から連続する、胴部4より肉薄のストレート部3aを有している。ストレート部3aは、径が絞り込まれながら肉厚を徐々に増していく絞り部3bを経て、胴部4に連続するように形成されている。
ここで、首下部3は、ストレート部3a及び絞り部3bを含めて、肉厚、長さ等を所望の値に設定することができ、成形するボトル容器の大きさ、形状、肉厚等に応じて任意に設定可能である。
The neck lower part 3 is a part (predetermined range) of the preform 1 located between the body part 4 and the mouth part 2, and has a straight part 3 a continuous from the mouth part 2 and thinner than the body part 4. Yes. The straight portion 3a is formed so as to be continuous with the body portion 4 through a narrowed portion 3b that gradually increases in thickness while being narrowed in diameter.
Here, the neck lower part 3 including the straight part 3a and the throttle part 3b can be set to a desired thickness, length, etc., and the size, shape, thickness, etc. of the bottle container to be molded It can be set arbitrarily depending on the situation.

本実施形態では、図2に示す胴部4の肉厚Taとストレート部3aの肉厚Tcの比が、1.2≦Ta/Tc≦1.7となるように設定してある。
このような範囲に設定するのは、胴部4とストレート部3aの肉厚比が1.2より小さくなる(Ta/Tc<1.2)ようにプリフォーム1を射出成形することは困難であり、また、Ta/Tcが1.7を超えると(Ta/Tc>1.7)、胴部4とストレート部3aの肉厚差が大きくなり過ぎ、ストレート部3aに局部延伸、過延伸が生じる傾向が強くなるためである。
In the present embodiment, the ratio of the thickness Ta of the body portion 4 shown in FIG. 2 to the thickness Tc of the straight portion 3a is set to satisfy 1.2 ≦ Ta / Tc ≦ 1.7.
Setting such a range makes it difficult to injection-mold the preform 1 so that the thickness ratio of the body portion 4 and the straight portion 3a is smaller than 1.2 (Ta / Tc <1.2). Yes, if Ta / Tc exceeds 1.7 (Ta / Tc> 1.7), the thickness difference between the body 4 and the straight portion 3a becomes too large, and the straight portion 3a is locally stretched and overstretched. This is because the tendency to occur becomes stronger.

また、ストレート部3aの筒長手方向の長さLaと肉厚Tcの比は、3≦La/Tc≦5となるように設定してある。ストレート部3aが短すぎると(La/Tc<3)、首下部に局部延伸、過延伸が生じる傾向が強くなってしまい、ストレート部3aを長くしすぎると(La/Tc>5)、射出成形の際に材料が入りづらく成形不良が生じるからである。   Further, the ratio of the length La of the straight portion 3a in the longitudinal direction of the tube to the thickness Tc is set to satisfy 3 ≦ La / Tc ≦ 5. If the straight part 3a is too short (La / Tc <3), the tendency of local stretching and overstretching at the lower neck becomes strong, and if the straight part 3a is too long (La / Tc> 5), injection molding is performed. This is because it is difficult for the material to enter during molding.

さらに、絞り部3bの絞り比、すなわち、胴部4の外径φyとストレート部3aの外径φxの比は、0.4≦φy/φx≦1.3となるように設定してある。この絞り比が小さすぎると(φy/φx<0.4)、局部延伸や過延伸が生じる傾向が強くなってしまい、大きすぎると(φy/φx>1.3)、ストレート部3aと絞り部3bが十分に延伸されず、段付部5aが先に延伸され、過延伸になってしまうからである。   Further, the aperture ratio of the aperture portion 3b, that is, the ratio of the outer diameter φy of the body portion 4 to the outer diameter φx of the straight portion 3a is set to satisfy 0.4 ≦ φy / φx ≦ 1.3. If this drawing ratio is too small (φy / φx <0.4), the tendency to cause local stretching or overstretching becomes strong. If it is too large (φy / φx> 1.3), the straight portion 3a and the drawn portion This is because 3b is not sufficiently stretched, and the stepped portion 5a is stretched first, resulting in overstretching.

具体的には、後述する図4に示すような容量2000mlのボトル容器用のプリフォームの場合、樹脂重量は約30〜40gで、胴部4の肉厚は約3〜4mmに設定する。この場合、図2に示す胴部の肉厚Taとストレート部の肉厚Tcの差が、Ta−Tc=1.6mm以下となるように設定する。
さらに、ストレート部3a及び絞り部3bは、筒長手方向の長さが所望の範囲に設定可能であり、ストレート部3aの筒長手方向の長さLaが、5〜9mmとなるように設定し、絞り部3bの筒長手方向の長さLbが、7〜15mmとなるように設定する。また、胴部4の筒長手方向の長さLcも所望の範囲に設定可能であり、56〜86mmとなるように設定する。
このような値に設定することで、容量2000mlで平均肉厚が約0.22mmのボトル容器が得られるようになる。
Specifically, in the case of a bottle container preform having a capacity of 2000 ml as shown in FIG. 4 to be described later, the resin weight is set to about 30 to 40 g, and the thickness of the body portion 4 is set to about 3 to 4 mm. In this case, the difference between the thickness Ta of the body portion shown in FIG. 2 and the thickness Tc of the straight portion is set to be Ta−Tc = 1.6 mm or less.
Furthermore, the straight part 3a and the narrowed part 3b can be set so that the length in the cylinder longitudinal direction can be set to a desired range, and the length La in the cylinder longitudinal direction of the straight part 3a is set to 5 to 9 mm, The length Lb of the throttle part 3b in the cylinder longitudinal direction is set to be 7 to 15 mm. Further, the length Lc of the barrel portion 4 in the longitudinal direction of the cylinder can also be set to a desired range, and is set to be 56 to 86 mm.
By setting to such a value, a bottle container having a capacity of 2000 ml and an average wall thickness of about 0.22 mm can be obtained.

このようにして、首下部3に、胴部4より肉薄のストレート部3a、及び径が絞り込まれながら肉厚を徐々に増してストレート部3aと胴部4とを接続する絞り部3bを設け、その肉厚と長さ、絞り部3bの絞り比を適宜設定可能とすることで、ストレート部3a及び絞り部3bを含む首下部3の全体を均一に延伸させることができる。
そして、後述する工程によりプリフォーム1が延伸ブロー成形されると、首下部3が全体的に均一に延伸され、胴部4の延伸負担を小さくして、結果的にプリフォーム全体が均一に延伸されるようになる。
なお、図1及び図2に示す例では、ストレート部3aは、口部2から絞り部3aに至るまで、肉厚Tcが均一になるように形成してあるが、例えば、ストレート部3aの外面又は内面を傾斜させることで、肉厚を変更することも可能である。このようにすると、肉厚部と肉薄部とで延伸量を異ならせて延伸量を調整することができる。
In this way, the neck portion 3 is provided with a straight portion 3a that is thinner than the trunk portion 4, and a throttle portion 3b that gradually increases the thickness while the diameter is narrowed to connect the straight portion 3a and the trunk portion 4. By making it possible to set the thickness and length and the drawing ratio of the drawn portion 3b as appropriate, the entire neck lower portion 3 including the straight portion 3a and the drawn portion 3b can be stretched uniformly.
When the preform 1 is stretch-blow-molded by the process described later, the neck lower portion 3 is stretched uniformly uniformly, reducing the stretching burden on the body 4, and as a result, the entire preform is stretched uniformly. Will come to be.
In the example shown in FIGS. 1 and 2, the straight portion 3a is formed so that the thickness Tc is uniform from the mouth portion 2 to the throttle portion 3a. For example, the outer surface of the straight portion 3a Alternatively, it is possible to change the wall thickness by inclining the inner surface. If it does in this way, the amount of extending | stretching can be varied between a thick part and a thin part, and an extending amount can be adjusted.

2.構成成分
本実施形態で使用するプリフォーム1を構成する熱可塑性樹脂は、延伸ブロー成形及び熱結晶化可能な樹脂であれば任意のものを使用することができる。
2. Component As the thermoplastic resin constituting the preform 1 used in the present embodiment, any resin can be used as long as it can be stretch blow molded and thermally crystallized.

具体的には、ポリエチレンテレフタレート,ポリブチレンテレフタレート,ポリエチレンナフタレート,ポリカーボネート,ポリアリレート、ポリ乳酸又はこれらの共重合体等の熱可塑性ポリエステル、これらの樹脂あるいは他の樹脂とのブレンド物が好適であり、特に、ポリエチレンテレフタレート等のエチレンテレフタレート系熱可塑性ポリエステルが好適に使用される。
また、アクリロニトリル樹脂,ポリプロピレン,プロピレン−エチレン共重合体,ポリエチレン等も使用することができる。
これらの樹脂には、成形品の品質を損なわない範囲内で種々の添加剤、例えば、着色剤,紫外線吸収剤,離型剤,滑剤,核剤,酸化防止剤,帯電防止剤等を配合することができる。
Specifically, thermoplastic polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyarylate, polylactic acid or copolymers thereof, blends of these resins or other resins are suitable. In particular, an ethylene terephthalate thermoplastic polyester such as polyethylene terephthalate is preferably used.
Further, acrylonitrile resin, polypropylene, propylene-ethylene copolymer, polyethylene and the like can also be used.
These resins are blended with various additives such as colorants, ultraviolet absorbers, mold release agents, lubricants, nucleating agents, antioxidants, antistatic agents, etc. within the range that does not impair the quality of the molded product. be able to.

プリフォーム1を構成するエチレンテレフタレート系熱可塑性ポリエステルは、エステル反復単位の大部分、一般に70モル%以上をエチレンテレフタレート単位を占めるものであり、ガラス転移点(Tg)が50〜90℃、融点(Tm)が200〜275℃の範囲にあるものが好適である。
エチレンテレフタレート系熱可塑性ポリエステルとしては、ポリエチレンテレフタレート(PET)が耐圧性,耐熱性,耐熱圧性等の点で特に優れているが、エチレンテレフタレート単位以外にイソフタル酸やナフタレンジカルボン酸等の二塩基酸とプロピレングリコール等のジオールからなるエステル単位の少量を含む共重合ポリエステルも使用することができる。
The ethylene terephthalate-based thermoplastic polyester constituting the preform 1 occupies most of the ester repeating units, generally 70 mol% or more of the ethylene terephthalate units, and has a glass transition point (Tg) of 50 to 90 ° C., a melting point ( Those having a Tm) in the range of 200 to 275 ° C are preferred.
As an ethylene terephthalate-based thermoplastic polyester, polyethylene terephthalate (PET) is particularly excellent in terms of pressure resistance, heat resistance, heat pressure resistance, etc. In addition to ethylene terephthalate units, dibasic acids such as isophthalic acid and naphthalenedicarboxylic acid Copolyesters containing a small amount of ester units composed of diols such as propylene glycol can also be used.

また、本実施形態のプリフォーム1は、単層(一層)の熱可塑性ポリエステル層で構成される場合の他、二層以上の熱可塑性ポリエステル層により構成することもできる。
さらに、本実施形態のプリフォーム1は、二層以上の熱可塑性ポリエステル層からなる内層及び外層の間に封入される中間層を備えることができ、中間層をバリヤー層や酸素吸収層とすることができる。
このようにバリヤー層,酸素吸収層を備えることにより、ボトル容器内への外部からの酸素の透過を抑制し、ボトル容器内の内容物の外部からの酸素による変質を防止することができ、特に炭酸ガス入り飲料用のボトル容器に好適となる。
ここで、酸素吸収層としては、酸素を吸収して酸素の透過を防ぐものであれば任意のものを使用することができるが、酸化可能有機成分及び遷移金属触媒の組合せ、あるいは実質的に酸化しないガスバリヤー性樹脂,酸化可能有機成分及び遷移金属触媒の組み合わせを使用することが好適である。
Further, the preform 1 of the present embodiment can be composed of two or more thermoplastic polyester layers in addition to the case of being composed of a single layer (one layer) of thermoplastic polyester layer.
Furthermore, the preform 1 of the present embodiment can include an intermediate layer enclosed between an inner layer and an outer layer composed of two or more thermoplastic polyester layers, and the intermediate layer is a barrier layer or an oxygen absorbing layer. Can do.
By providing the barrier layer and the oxygen absorbing layer in this way, it is possible to suppress the permeation of oxygen from the outside into the bottle container, and to prevent the deterioration of the contents in the bottle container due to the oxygen from the outside. Suitable for bottle containers for beverages containing carbon dioxide gas.
Here, as the oxygen absorbing layer, any layer can be used as long as it absorbs oxygen and prevents permeation of oxygen, but a combination of an oxidizable organic component and a transition metal catalyst, or substantially oxidized. It is preferred to use a combination of non-gas barrier resin, oxidizable organic component and transition metal catalyst.

[プラスチックボトル容器の製造方法]
次に、以上のようなプリフォームを使用した本実施形態に係るプラスチックボトル容器の製造方法について具体的に説明する。
1.プリフォームの製造
プリフォーム1は、公知の射出成形や押出成形により有底筒状のプリフォーム(パリソン)を製造することができる。上述した胴部4と底部5の間の段付部5a、口部3と胴部4の間のストレート部3a及び絞り部3bを含む首下部3についても、公知の射出成形等により所望の形状、寸法で製造可能である。
なお、プリフォーム1として、中間層に酸素吸収層を備える多層プリフォームを使用する場合には、従来から公知の共射出成形機等を用いて、内外層をポリエステル樹脂とし、内外層の間に一層又は二層以上の酸素吸収層を挿入し、射出用プリフォーム金型の形状に対応した、ヒール部及び開口部を有する多層プリフォームを製造することができる。
[Plastic bottle container manufacturing method]
Next, a method for producing a plastic bottle container according to the present embodiment using the above preform will be specifically described.
1. Production of Preform The preform 1 can produce a bottomed cylindrical preform (parison) by known injection molding or extrusion molding. For the neck lower part 3 including the stepped part 5a between the body part 4 and the bottom part 5 described above, the straight part 3a between the mouth part 3 and the body part 4 and the throttle part 3b, a desired shape is obtained by known injection molding or the like. Can be manufactured in dimensions.
When a multilayer preform having an oxygen absorbing layer in the intermediate layer is used as the preform 1, the inner and outer layers are made of polyester resin using a conventionally known co-injection molding machine or the like, and between the inner and outer layers. A multilayer preform having a heel portion and an opening corresponding to the shape of the injection preform mold can be manufactured by inserting one or more oxygen absorbing layers.

2.延伸ブロー成形
次に、プリフォーム1を二軸延伸ブロー成形する。
本実施形態では、まず、プリフォーム1をガラス転移点(Tg)以上の延伸温度に加熱する。プリフォーム1の加熱は、図1に示すように、ヒータ101などの公知の加熱手段により行う。また、この加熱の際には、図1に示すように、非結晶の口部2が加熱されないように加熱防止用冷却ガイド102で保護される。なお、口部2を予め結晶化させたプリフォームを使用することもできる。
2. Stretch Blow Molding Next, the preform 1 is biaxially stretch blow molded.
In the present embodiment, first, the preform 1 is heated to a stretching temperature equal to or higher than the glass transition point (Tg). The preform 1 is heated by a known heating means such as a heater 101 as shown in FIG. Further, at the time of this heating, as shown in FIG. 1, the non-crystalline mouth portion 2 is protected by a heating prevention cooling guide 102 so as not to be heated. A preform in which the mouth 2 is crystallized in advance can also be used.

本実施形態では、プリフォーム1を加熱限界温度である約120℃で加熱するようにしてある。通常の肉厚のボトル容器を製造する場合には、プリフォームの加熱温度は約85℃〜110℃であるが、本実施形態では加熱限界である120℃近傍まで温度を上げることにより、樹脂の粘性を落とし、延伸成形で発生する歪みを軽減するようにしてある。但し、120℃を超える高温で加熱すると、ブロー成形後にボトルが白化(白濁)してしまうため好ましくない。本実施形態において、好ましいプリフォームの加熱温度は、110〜120度である。   In this embodiment, the preform 1 is heated at a heating limit temperature of about 120 ° C. When a normal thick bottle container is manufactured, the heating temperature of the preform is about 85 ° C. to 110 ° C. In this embodiment, the temperature of the resin is increased by raising the temperature to around 120 ° C. which is the heating limit. The viscosity is reduced, and the strain generated by stretch molding is reduced. However, heating at a high temperature exceeding 120 ° C. is not preferable because the bottle is whitened (white turbid) after blow molding. In the present embodiment, a preferable preform heating temperature is 110 to 120 degrees.

次に、加熱したプリフォーム1は、所定の熱処理(ヒートセット)温度に加熱された金型内において二軸延伸ブロー成形する。
具体的には、図3(a)〜(b)に示すように、まず、加熱したプリフォーム1が金型103内にセットされ(図3(a)参照)、次に、ストレッチロッド(延伸ロッド)104により縦方向(軸方向)に延伸されるとともに、ブローエアによって主に横方向(周方向)に延伸され、金型により賦形される際には縦方向方にも延伸される(図3(b)参照)。
Next, the heated preform 1 is subjected to biaxial stretch blow molding in a mold heated to a predetermined heat treatment (heat set) temperature.
Specifically, as shown in FIGS. 3A to 3B, first, the heated preform 1 is set in a mold 103 (see FIG. 3A), and then a stretch rod (stretched). (Rod) 104 is stretched in the longitudinal direction (axial direction) by blow air, and is stretched mainly in the lateral direction (circumferential direction) by blow air, and is also stretched in the longitudinal direction when it is shaped by a mold (see FIG. 3 (b)).

このとき、本実施形態では、プリフォーム1を構成する材料や、プリフォーム1を容器形態に延伸する際の延伸倍率、さらには容器1の形状などを考慮して、ブローエアを70〜180℃の温度に設定する。これにより、延伸過程にあるプリフォーム1には絶えず熱が加えられることになり、延伸工程の全工程において延伸に適した軟化状態を維持させることができる。
したがって、従来、プリフォームの延伸工程の後期において、ある程度の固化が進行したプリフォームをさらに延伸することにより生じていた、過延伸による白化を有効に回避することができる。
At this time, in this embodiment, the blow air is set to 70 to 180 ° C. in consideration of the material constituting the preform 1, the draw ratio when the preform 1 is drawn into a container form, and the shape of the container 1. Set to temperature. Accordingly, heat is constantly applied to the preform 1 in the stretching process, and a softened state suitable for stretching can be maintained in all the stretching processes.
Accordingly, it is possible to effectively avoid whitening due to overstretching, which has conventionally occurred by further stretching a preform that has been solidified to some extent in the later stage of the preform stretching step.

また、ブローエアは、プリフォーム1を延伸させるために加圧供給されるが、その圧力は、延伸速度や、ブローエアの設定温度などを考慮して、2〜4MPaに設定するのが好ましい。   The blow air is supplied under pressure in order to stretch the preform 1, and the pressure is preferably set to 2 to 4 MPa in consideration of the stretching speed, the set temperature of the blow air, and the like.

ここで、本実施形態で使用するプリフォーム1は、延伸の際に、段付部5aが、連続する底部5を含めて全体として均一に延伸される。また、首下部3が、ストレート部3a及び絞り部3bを含めて全体として均一に延伸される。
これによって、プリフォーム1の全体が均一に延伸されるとともに、ブローエアの温度設定により、過延伸による白化を有効に回避することができるため、局所的な延伸や過延伸が発生せず、その結果、均一な肉厚分布のボトル容器10が成形されることになる。
Here, in the preform 1 used in the present embodiment, the stepped portion 5a is uniformly stretched as a whole including the continuous bottom portion 5 during stretching. Moreover, the neck lower part 3 is uniformly extended as a whole including the straight part 3a and the throttle part 3b.
As a result, the entire preform 1 is uniformly stretched, and whitening due to overstretching can be effectively avoided by setting the temperature of the blow air, so that local stretching and overstretching do not occur. The bottle container 10 having a uniform wall thickness distribution is formed.

また、本実施形態におけるブロー成形体の延伸倍率は、縦方向2.4〜3.1倍、横方向で4.5〜6倍とし、縦×横で10.8〜18.6倍となるように設定する。
通常の肉厚のボトル容器の場合、ブロー成形体の延伸倍率は、縦方向約2.2倍、横方向約5倍程度で、縦×横で約11倍程度となっている。
本実施形態では、プリフォーム1の形状によりプリフォーム1の全体が均一に延伸されるとともに、ブローエアの温度設定により過延伸による白化を有効に回避することができ、局所的延伸や過延伸を発生させることなく均一な延伸が可能であるため、均一な肉厚分布で可能な限り肉薄のボトル容器を得るために、少なくとも上記の延伸倍率とすることが好ましい。
Moreover, the draw ratio of the blow molded product in the present embodiment is 2.4 to 3.1 times in the vertical direction, 4.5 to 6 times in the horizontal direction, and 10.8 to 18.6 times in the vertical and horizontal directions. Set as follows.
In the case of a normal thick bottle container, the stretch ratio of the blow molded product is about 2.2 times in the vertical direction, about 5 times in the horizontal direction, and about 11 times in the vertical and horizontal directions.
In the present embodiment, the entire preform 1 is uniformly stretched by the shape of the preform 1, and whitening due to overstretching can be effectively avoided by setting the temperature of the blow air, and local stretching and overstretching occur. In order to obtain a bottle container that is as thin as possible with a uniform wall thickness distribution, at least the above draw ratio is preferable.

3.ヒートセット
延伸されたブロー成形体は、金型内でヒートセット(熱固定)される。
ヒートセットは、上述したブロー金型103を、所定温度に加熱し、二軸延伸ブロー時に、ブロー成形体の器壁の外側を金型内面に所定時間接触させて熱処理を行う。
ここで、本実施形態では、ヒートセット温度として金型を約105〜115℃となるように加熱する。
3. Heat setting The stretched blow molded article is heat set (heat-set) in a mold.
In the heat setting, the above-described blow mold 103 is heated to a predetermined temperature, and at the time of biaxial stretching blow, the outer wall of the blow molded article is brought into contact with the inner surface of the mold for a predetermined time for heat treatment.
Here, in this embodiment, the mold is heated to a temperature of about 105 to 115 ° C. as the heat set temperature.

また、ヒートセットの熱処理時間(ブロー時間)は、ブロー成形体の厚みや温度によっても相違するが、一般に1〜10秒、好ましくは2〜5秒程度である。また、その後の冷却時間も、熱処理温度や冷却用流体の種類により異なるが、一般に0.1〜10秒、好ましくは0.2〜5秒程度である。
このヒートセットにより、ブロー成形体は結晶化される。
なお、このブロー成形体の結晶化度は、容器の肉厚,形状,ヒートセット温度,時間等の条件によるため、これらの条件を最適化することにより、ボトル容器10の胴部13の結晶化度を、例えば、約30〜40%程度の好適な範囲とすることができる。
Moreover, although the heat processing time (blow time) of heat set changes also with the thickness and temperature of a blow molded object, it is generally 1 to 10 seconds, Preferably it is about 2 to 5 seconds. Further, the subsequent cooling time varies depending on the heat treatment temperature and the type of cooling fluid, but is generally about 0.1 to 10 seconds, preferably about 0.2 to 5 seconds.
By this heat setting, the blow molded product is crystallized.
The crystallinity of the blow molded product depends on conditions such as the thickness, shape, heat set temperature, time, etc. of the container. By optimizing these conditions, the crystallization of the body portion 13 of the bottle container 10 is achieved. The degree can be set to a suitable range of about 30 to 40%, for example.

4.クーリングブロー
以上の所定時間の熱処理後、図3(c)に示すように、クーリングブローロッド105から噴出する内部冷却用流体により、ブロー成形体内部を冷却する。
ここで、本実施形態では、クーリングブローのエア供給圧を約4MPaとしてある。通常の肉厚のボトル容器をブロー成形する場合、クーリングブローのエア供給圧は約3MPa程度であるが、本実施形態では、エアの供給圧力を高めることにより、ブロー成形後のボトルの取り出し温度を低減してヒケの発生を防止するようにしてある。
4). Cooling Blow After the heat treatment for the predetermined time, the inside of the blow molded body is cooled by the internal cooling fluid ejected from the cooling blow rod 105 as shown in FIG.
Here, in this embodiment, the air supply pressure of the cooling blow is about 4 MPa. When a normal thick bottle container is blow-molded, the air supply pressure of the cooling blow is about 3 MPa. However, in this embodiment, by increasing the air supply pressure, the temperature at which the bottle is taken out after blow molding is increased. This is reduced to prevent the occurrence of sink marks.

なお、冷却用流体としては、常温の空気,冷却された各種気体、例えば、−40℃〜+10℃の窒素,空気,炭酸ガス等のほか、化学的に不活性な液化ガス、例えば、液化窒素ガス,液化炭酸ガス,液化トリクロロフルオロメタンガス,液化ジクロロジフルオロメタンガス,他の液化脂肪族炭化水素ガス等を使用することができる。この冷却用流体には、水等の気化熱の大きい液体のミストを共存させることもできる。以上のような冷却用流体を使用することにより、顕著な冷却温度を得ることができる。   The cooling fluid includes normal temperature air, various cooled gases, for example, nitrogen at −40 ° C. to + 10 ° C., air, carbon dioxide gas, etc., and a chemically inert liquefied gas such as liquefied nitrogen. Gas, liquefied carbon dioxide gas, liquefied trichlorofluoromethane gas, liquefied dichlorodifluoromethane gas, other liquefied aliphatic hydrocarbon gas, and the like can be used. In this cooling fluid, a liquid mist having a large heat of vaporization such as water can coexist. By using the cooling fluid as described above, a remarkable cooling temperature can be obtained.

その後は、図3(d)に示すように、成形体は金型から取り出され、ボトル容器10が得られる。金型から取り出したブロー成形体(ボトル容器10)は、放冷により、又は冷風を吹き付けることにより冷却する。これで、延伸ブロー成形工程が完了する。
以上のような工程にしたがって実施される本実施形態は、例えば、図4に示すようなボトル容器10を製造するのに特に好適である。
Thereafter, as shown in FIG. 3D, the molded body is taken out from the mold, and the bottle container 10 is obtained. The blow molded body (bottle container 10) taken out from the mold is cooled by cooling or by blowing cold air. This completes the stretch blow molding process.
This embodiment implemented according to the above processes is particularly suitable for manufacturing a bottle container 10 as shown in FIG. 4, for example.

[ボトル容器]
図4は、本実施形態により製造されるボトル容器の一例を示し、図4(a)は、ボトル容器の正面図であり、図4(b)、(c)は、それぞれ図4(a)のA−A横端面図、B−B横端面図である。なお、作図上、図4(b)、(c)では、ボトル容器10の肉厚を誇張している。
[Bottle container]
FIG. 4 shows an example of a bottle container manufactured according to the present embodiment, FIG. 4 (a) is a front view of the bottle container, and FIGS. 4 (b) and 4 (c) respectively show FIG. 4 (a). It is an AA lateral end view and BB lateral end view. In the drawing, the thickness of the bottle container 10 is exaggerated in FIGS. 4 (b) and 4 (c).

図4に示すボトル容器10は、口部20、胴部30及びヒール部40を備えており、ほぼ円筒状の容器形状を有している。胴部30の高さ方向ほぼ中央には、径を絞り込んだウェスト部50が形成されている。そして、胴部30は、ウェスト部50を境に、上側胴部31と下側胴部32とに分けられている。
ここで、高さ方向とは、口部20を上にしてボトル容器10を水平面に置いたときに、水平面に直交する方向に沿った方向をいうものとする。
The bottle container 10 shown in FIG. 4 includes a mouth part 20, a body part 30, and a heel part 40, and has a substantially cylindrical container shape. A waist part 50 with a narrowed diameter is formed in the center of the body part 30 in the height direction. The body part 30 is divided into an upper body part 31 and a lower body part 32 with the waist part 50 as a boundary.
Here, the height direction means a direction along a direction perpendicular to the horizontal plane when the bottle container 10 is placed on a horizontal plane with the mouth portion 20 facing up.

図示する例において、高さ方向に沿って延びる複数の稜線311が形成されている。それぞれの稜線311は、上側胴部31の側面に沿って形成されており、正面視したときに直線状に観察される。
そして、これらの稜線311の間には、ボトル容器10の内圧が減少したときに、ボトル容器1の内方に緩やかに湾曲して圧力の減少を吸収する減圧吸収面312が十二面形成されており、上側胴部31の横断面形状は、正十二角形状に形成されている(図4(b)参照)。
また、下側胴部32には、高さ方向に沿って螺旋状に延びる複数の稜線321が形成されており、これらの稜線321の間には、下側胴部32の横断面形状が正十六角形状となるように(図4(c)参照)、十六面の減圧吸収面322が均等に形成されている。
In the illustrated example, a plurality of ridge lines 311 extending along the height direction are formed. Each ridgeline 311 is formed along the side surface of the upper body portion 31 and is observed in a straight line when viewed from the front.
Between these ridges 311, when the internal pressure of the bottle container 10 decreases, twelve decompression absorbing surfaces 312 that gently curve inward of the bottle container 1 and absorb the pressure decrease are formed. The cross-sectional shape of the upper body 31 is a regular dodecagon (see FIG. 4B).
In addition, a plurality of ridge lines 321 extending spirally along the height direction are formed on the lower body section 32, and the cross-sectional shape of the lower body section 32 is correct between the ridge lines 321. The sixteen decompression absorbing surfaces 322 are uniformly formed so as to have a dodecagonal shape (see FIG. 4C).

ここで、上側胴部31及び下側胴部32に形成する減圧吸収面312,322の面数は、隣接する減圧吸収面312,322の交わる角度が135〜163.7度、好ましくは144〜162度となるように設定される。
具体的には、上型胴部31の最大径φbが95〜115mm程度である場合、上型胴部31に形成する減圧吸収面312の面数は八〜十六面、好ましくは十〜十四面である。また、下型胴部32の最大径φcが100〜120mm程度である場合、下側胴部32に形成する減圧吸収面322の面数は十〜二十二面、好ましくは十二〜二十面である。
なお、上側胴部31及び下側胴部32の横断面形状を正多角形状に形成する場合、隣接する減圧吸収面312が交わる角度は、正八角形で135度、正十角形で144度、正二十角形で162度、正二十二角形で163.6度である。
Here, the number of the reduced pressure absorption surfaces 312 and 322 formed on the upper body portion 31 and the lower body portion 32 is such that the angle at which the adjacent reduced pressure absorption surfaces 312 and 322 intersect is 135 to 163.7 degrees, preferably 144 to It is set to be 162 degrees.
Specifically, when the maximum diameter φb of the upper mold body 31 is about 95 to 115 mm, the number of decompression absorption surfaces 312 formed on the upper mold body 31 is 8 to 16 surfaces, preferably 10 to 10 surfaces. There are four sides. When the maximum diameter φc of the lower mold body 32 is about 100 to 120 mm, the number of the reduced pressure absorption surfaces 322 formed on the lower body 32 is 10 to 22, preferably 12 to 20. Surface.
In addition, when the cross-sectional shape of the upper trunk portion 31 and the lower trunk portion 32 is formed in a regular polygon shape, the angle at which the adjacent reduced pressure absorption surfaces 312 intersect is 135 degrees for a regular octagon, 144 degrees for a regular decagon, The angle is 162 degrees for the icosahedron and 163.6 degrees for the regular icosahedron.

通常、過延伸が生じ易いのは、周方向ではコーナー部及びその近傍であり、コーナー部がとがっているほど顕著となる。稜線311,321の両脇に位置する減圧吸収面321,322がなす角度を上記範囲の比較的鈍い角度とし、稜線311,321をとがらせるようにすれば、コーナー部に相当する稜線311,321及びその近傍での過延伸を抑制することができ、本実施形態の製造方法を適用するにあたって、より有効に過延伸による白化を回避することができる。   Normally, overstretching is likely to occur in the circumferential direction at the corner portion and its vicinity, and becomes more noticeable as the corner portion is sharpened. If the angle formed by the reduced pressure absorbing surfaces 321 and 322 located on both sides of the ridge lines 311 and 321 is a relatively dull angle within the above range, and the ridge lines 311 and 321 are sharpened, the ridge lines 311 and 321 corresponding to the corner portions are formed. In addition, overstretching in the vicinity thereof can be suppressed, and whitening due to overstretching can be avoided more effectively in applying the manufacturing method of the present embodiment.

ところで、図示するボトル容器の例において、減圧吸収面312,322を上記したような構造とするのは、上側胴部31及び下側胴部32の周方向に沿った全面を減圧吸収面として機能させ、ボトル容器1の減圧吸収性能を向上させるためである。また、高さ方向に沿って形成された稜線311,321は、柱状の構造部位として機能し、特に、縦方向の荷重に対する耐荷重強度を向上させるものである。さらに、このような稜線311,321を形成することにより、成形時のひけを防止して容器1の成形性を良好なものとすることもできる。   By the way, in the example of the bottle container shown in the figure, the reduced pressure absorption surfaces 312 and 322 have the above-described structure because the entire surface along the circumferential direction of the upper barrel portion 31 and the lower barrel portion 32 functions as the reduced pressure absorption surface. This is because the reduced pressure absorption performance of the bottle container 1 is improved. Further, the ridge lines 311 and 321 formed along the height direction function as columnar structural portions, and in particular, improve load resistance strength against a load in the vertical direction. Furthermore, by forming such ridge lines 311 and 321, sink marks during molding can be prevented and the moldability of the container 1 can be improved.

したがって、減圧吸収面312,322の面数が、前述した範囲に満たないと、稜線311,321の両脇に位置する減圧吸収面312,322がなす角度が比較的鋭くなってしまい、稜線311,321及びその近傍に過延伸が生じる傾向が強くなるとともに、稜線311,321の数も減少するので、前述したような、耐荷重強度の向上や、ひけ防止などの稜線311,321を形成することによって得られる効果も不十分になってしまう。また、減圧吸収面312,322が大きくなるため、成形後のひけが生じたり、減圧吸収時の一面あたりの変形量が大きくなり過ぎて、ボトル容器1の外観に悪影響を及ぼしてしまう。   Therefore, if the number of decompression absorbing surfaces 312 and 322 is less than the above-described range, the angle formed by the decompression absorbing surfaces 312 and 322 located on both sides of the ridge lines 311 and 321 becomes relatively sharp, and the ridge line 311 , 321 and the vicinity thereof, and the number of the ridge lines 311, 321 is also reduced, so that the ridge lines 311, 321 for improving the load resistance strength and preventing the sink are formed as described above. The effect obtained by this will also become inadequate. In addition, since the reduced pressure absorbing surfaces 312 and 322 become large, sink marks after molding occur, or the amount of deformation per surface at the time of absorbing the reduced pressure becomes too large, which adversely affects the appearance of the bottle container 1.

一方、上記範囲を超えて減圧吸収面312,322を形成すると、稜線311,321及びその近傍に過延伸が生じ難くなり、また、稜線311,321によるひけ防止などの効果も得られるものの、減圧吸収面312,322が小さくなるため、減圧吸収時の一面あたりの減圧吸収量が減ってしまい、十分な減圧吸収性能が得られなくなってしまう。さらに、隣接する減圧吸収面312,322どうしがなす角度が鈍くなり過ぎてしまうので、容器形状保持のための稜線311,321の骨子としての機能が損なわれ、耐荷重強度も減少する。   On the other hand, when the reduced pressure absorbing surfaces 312 and 322 are formed beyond the above range, overstretching hardly occurs at the ridge lines 311 and 321 and the vicinity thereof, and an effect such as sink prevention by the ridge lines 311 and 321 can be obtained. Since the absorption surfaces 312 and 322 become smaller, the amount of reduced pressure absorption per surface during reduced pressure absorption decreases, and sufficient reduced pressure absorption performance cannot be obtained. Furthermore, since the angle formed between the adjacent vacuum absorbing surfaces 312 and 322 becomes too dull, the function of the ridge lines 311 and 321 for maintaining the container shape is impaired, and the load bearing strength is also reduced.

このように、図4に示すようなボトル容器10を製造するにあたり、減圧吸収面312,322の面数は、ボトル容器10の成形性、要求される耐荷重強度と減圧吸収性能とのバランス、減圧吸収時のボトル容器10の変形具合、ボトル容器10のデザインなどを考慮して適宜設定されるが、本実施形態では、これらを考慮するとともに、稜線311,321及びその近傍での過延伸を抑制するために、減圧吸収面312,322がなす角度と、延伸ブロー成形の際のブローエアの温度をバランスよく設定することで、過延伸による白化を防止しつつ成形性よくボトル容器を製造することができる。   Thus, in manufacturing the bottle container 10 as shown in FIG. 4, the number of the reduced pressure absorption surfaces 312 and 322 is the balance between the moldability of the bottle container 10, the required load bearing strength and the reduced pressure absorption performance, Although it is appropriately set in consideration of the deformation of the bottle container 10 at the time of absorbing the reduced pressure, the design of the bottle container 10, etc., in this embodiment, while considering these, overstretching in the ridge lines 311 and 321 and the vicinity thereof is performed. In order to suppress, by setting the angle formed by the reduced pressure absorbing surfaces 312 and 322 and the temperature of blow air at the time of stretch blow molding in a well-balanced manner, a bottle container is manufactured with good moldability while preventing whitening due to overstretching. Can do.

以下、本発明に係るプラスチックボトル容器の製造方法によってボトル容器を製造する場合の具体的な実施例を示す。
[実施例]
ポリエチレンテレフタレート(PET)を押出機に供給して重量35gのプリフォーム1を製造した。プリフォーム1には、胴部4と底部5の間に段付部5aを形成し、また、胴部4と口部2の間にストレート部3a及び絞り部3bを有する首下部3を形成した。
プリフォーム1の肉厚は、胴部4の肉厚Taが約3.5mm、ストレート部3aの肉厚Tcが約2mm、段付部5a及び底部5の肉厚Tbが約3mmとした。段付部5aの傾斜角度θは、約13°とした。ストレート部3aは長さLaが約7mm、絞り部3bは長さLbが約10mmとし、絞り部3bの絞り比φy/φxは0.9とした。胴部4の長さLcは70mmとした。
Hereinafter, the specific Example in the case of manufacturing a bottle container by the manufacturing method of the plastic bottle container which concerns on this invention is shown.
[Example]
Polyethylene terephthalate (PET) was supplied to an extruder to produce a preform 1 having a weight of 35 g. In the preform 1, a stepped portion 5 a is formed between the body portion 4 and the bottom portion 5, and a neck lower portion 3 having a straight portion 3 a and a narrowed portion 3 b is formed between the body portion 4 and the mouth portion 2. .
The thickness of the preform 1 was set such that the thickness Ta of the body portion 4 was about 3.5 mm, the thickness Tc of the straight portion 3a was about 2 mm, and the thickness Tb of the stepped portion 5a and the bottom portion 5 was about 3 mm. The inclination angle θ of the stepped portion 5a was about 13 °. The straight portion 3a has a length La of about 7 mm, the throttling portion 3b has a length Lb of about 10 mm, and the throttling portion 3b has a throttling ratio φy / φx of 0.9. The length Lc of the body part 4 was 70 mm.

このプリフォーム1をガラス転移点(Tg)以上の約115℃に加熱し、約110℃に加熱された金型内にセットして、約120℃の温度に加熱されたブローエアを約3MPaの圧力で供給し、一段ブロー成形法により二軸延伸ブローを行い、その後、約4MPaのエア供給圧でクーリングブローをして、図4に示すような内容量約2000mlのボトル容器を得た。
容器1の寸法は、高さHが310mm、口部2の開口径φaが26mm、上側胴部31の最大径φbが107mm、下側胴部32の最大径φcが110mm、ウェスト部5の最小径φdが72mmであった。また、胴部2の平均肉厚は、約0.22mmであった。
This preform 1 is heated to about 115 ° C. above the glass transition point (Tg), set in a mold heated to about 110 ° C., and blow air heated to a temperature of about 120 ° C. is pressurized to about 3 MPa. Then, biaxial stretching blow was performed by a single-stage blow molding method, and then cooling blow was performed at an air supply pressure of about 4 MPa to obtain a bottle container having an internal capacity of about 2000 ml as shown in FIG.
The dimensions of the container 1 are: the height H is 310 mm, the opening diameter φa of the mouth portion 2 is 26 mm, the maximum diameter φb of the upper body portion 31 is 107 mm, the maximum diameter φc of the lower body portion 32 is 110 mm, The small diameter φd was 72 mm. Moreover, the average thickness of the trunk | drum 2 was about 0.22 mm.

このようにして得られたボトル容器には、過延伸による白化が観察されなかった。また、局部延伸による偏肉も観察されず、全体的に均一な肉厚で形成されていた。   In the bottle container thus obtained, whitening due to overstretching was not observed. Moreover, the uneven thickness by local extending | stretching was not observed, but it formed with the uniform thickness as a whole.

以上、本発明について、好ましい実施形態を示して説明したが、本発明は、前述した実施形態にのみ限定されるものではなく、本発明の範囲で種々の変更実施が可能であることは言うまでもない。   Although the present invention has been described with reference to the preferred embodiment, it is needless to say that the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. .

例えば、上記実施形態により好適に製造されるボトル容器として、ほぼ円筒状のものを例示したが、本発明により製造されるプラスチックボトル容器は、円筒状のものに限られるものではない。例えば、角形ボトル容器であっても、必要に応じてコーナー部を丸めたり、面取りも併用したりすることにより実施可能である。
また、上記実施形態では、容量が2000mlのボトル容器を示したが、本発明の適用にあたってボトル容器の容量は特に限定されるものではない。従って、例えば容量1000mlのボトル容器であっても、また、容量1500mlのボトル容器であっても本発明の適用を妨げない。
For example, as the bottle container suitably manufactured according to the above embodiment, a substantially cylindrical one is illustrated, but the plastic bottle container manufactured according to the present invention is not limited to a cylindrical one. For example, even if it is a square bottle container, it can implement by rounding a corner part or using chamfering together as needed.
Moreover, in the said embodiment, although the capacity | capacitance of a 2000 ml bottle container was shown, in the application of this invention, the capacity | capacitance of a bottle container is not specifically limited. Therefore, for example, even a bottle container with a capacity of 1000 ml or a bottle container with a capacity of 1500 ml does not hinder the application of the present invention.

以上説明した本発明は、予備成形品であるポリエチレンテレフタレート等からなるプリフォーム(パリソン)を延伸ブロー成形してプラスチックボトル容器を製造する延伸ブロー成形方法に利用可能である。   The present invention described above can be used in a stretch blow molding method for manufacturing a plastic bottle container by stretch blow molding a preform (parison) made of polyethylene terephthalate or the like, which is a preformed product.

本発明に係るプラスチックボトル容器の製造方法の一実施形態において使用されるプリフォームの概略を示す断面図である。It is sectional drawing which shows the outline of the preform used in one Embodiment of the manufacturing method of the plastic bottle container which concerns on this invention. 図1に示すプリフォームの要部拡大図で、(a)は首下部付近の拡大図、(b)は段付部付近の拡大図である。FIG. 2 is an enlarged view of a main part of the preform shown in FIG. 本発明に係るプラスチックボトル容器の製造方法の一実施形態における製造工程の概略を示す工程図である。It is process drawing which shows the outline of the manufacturing process in one Embodiment of the manufacturing method of the plastic bottle container which concerns on this invention. 本発明に係るプラスチックボトル容器の製造方法の一実施形態により製造されるボトル容器の一例を示し、(a)はボトル容器の正面図であり、(b)、(c)は、それぞれ(a)のA−A横端面、B−B横端面を示している。An example of the bottle container manufactured by one Embodiment of the manufacturing method of the plastic bottle container which concerns on this invention is shown, (a) is a front view of a bottle container, (b), (c) is (a), respectively. A-A horizontal end face and BB horizontal end face are shown.

符号の説明Explanation of symbols

1 プリフォーム
2 口部
3 首下部
3a ストレート部
3b 絞り部
4 プリフォーム胴部
5 プリフォーム底部
5a プリフォーム段付部
10 ボトル容器
DESCRIPTION OF SYMBOLS 1 Preform 2 Mouth part 3 Neck lower part 3a Straight part 3b Restriction part 4 Preform trunk | drum 5 Preform bottom part 5a Preform step part 10 Bottle container

Claims (6)

有底筒状のプリフォームを所定温度で加熱し、延伸ブロー成形することにより、プラスチックボトル容器を製造する方法であって、
前記プリフォームを延伸ブローするブローエアを加熱加圧供給して、延伸過程にある前記プリフォームが、延伸に適した軟化状態を維持するようにしたことを特徴とするプラスチックボトル容器の製造方法。
A method of manufacturing a plastic bottle container by heating a bottomed cylindrical preform at a predetermined temperature and performing stretch blow molding,
A method for producing a plastic bottle container, characterized in that blow air for stretching and blowing the preform is heated and pressurized so that the preform in the stretching process maintains a softened state suitable for stretching.
前記ブローエアを70〜180℃の温度範囲で加熱供給する請求項1に記載のプラスチックボトル容器の製造方法。   The method for producing a plastic bottle container according to claim 1, wherein the blow air is heated and supplied in a temperature range of 70 to 180 ° C. 前記ブローエアを2〜4MPaの圧力範囲で加圧供給する請求項1又は2に記載のプラスチックボトル容器の製造方法。   The method for producing a plastic bottle container according to claim 1 or 2, wherein the blow air is pressurized and supplied in a pressure range of 2 to 4 MPa. 前記プリフォームを、110〜120℃の温度範囲で加熱後、延伸ブローを行う請求項1、2又は3に記載のプラスチックボトル容器の製造方法。   The method for producing a plastic bottle container according to claim 1, wherein the preform is stretched and blown after being heated in a temperature range of 110 to 120 ° C. 前記プリフォームの胴部と底部の間に段付部を形成することにより、前記段付部と前記底部部を一体的に延伸させるようにした請求項1〜4記載のプラスチックボトル容器の製造方法。   The manufacturing method of the plastic bottle container of Claims 1-4 which extended | stretched the said step part and the said bottom part integrally by forming a step part between the trunk | drum and bottom part of the said preform. . 前記プリフォームの口部と胴部の間に、前記胴部より肉薄のストレート部及び径が絞り込まれながら肉厚を徐々に増して前記ストレート部と前記胴部とを接続する絞り部を有する首下部を形成することにより、前記首下部を前記胴部と一体的に延伸させるようにした請求項1〜5記載のプラスチックボトル容器の製造方法。   A neck having a straight part that is thinner than the trunk part and a throttle part that gradually increases the thickness while the diameter is narrowed and connects the straight part and the trunk part between the mouth part and the trunk part of the preform. The method for producing a plastic bottle container according to claim 1, wherein the lower part of the neck is extended integrally with the body part by forming a lower part.
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JP2018083630A (en) * 2016-11-21 2018-05-31 東洋製罐株式会社 Polyester stretch blow molding vessel and its manufacturing method
WO2019107321A1 (en) 2017-11-29 2019-06-06 住友化学株式会社 Coating liquid for forming gas barrier layer
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JP7103121B2 (en) 2018-09-27 2022-07-20 大日本印刷株式会社 preform

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