JP4876385B2 - Resin hollow molded container and manufacturing method thereof - Google Patents
Resin hollow molded container and manufacturing method thereof Download PDFInfo
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- JP4876385B2 JP4876385B2 JP2004318180A JP2004318180A JP4876385B2 JP 4876385 B2 JP4876385 B2 JP 4876385B2 JP 2004318180 A JP2004318180 A JP 2004318180A JP 2004318180 A JP2004318180 A JP 2004318180A JP 4876385 B2 JP4876385 B2 JP 4876385B2
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Classifications
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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
- B29C2949/00—Indexing scheme relating to blow-moulding
- B29C2949/20—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer
- B29C2949/22—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer at neck portion
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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
- B29C2949/00—Indexing scheme relating to blow-moulding
- B29C2949/20—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer
- B29C2949/24—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer at flange portion
-
- 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
- B29C2949/00—Indexing scheme relating to blow-moulding
- B29C2949/20—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer
- B29C2949/26—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer at body portion
-
- 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
- B29C2949/00—Indexing scheme relating to blow-moulding
- B29C2949/20—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer
- B29C2949/28—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer at bottom portion
-
- 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
- B29C2949/00—Indexing scheme relating to blow-moulding
- B29C2949/30—Preforms or parisons made of several components
- B29C2949/3024—Preforms or parisons made of several components characterised by the number of components or by the manufacturing technique
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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
- B29C2949/00—Indexing scheme relating to blow-moulding
- B29C2949/30—Preforms or parisons made of several components
- B29C2949/3032—Preforms or parisons made of several components having components being injected
-
- 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
- B29C2949/00—Indexing scheme relating to blow-moulding
- B29C2949/30—Preforms or parisons made of several components
- B29C2949/3041—Preforms or parisons made of several components having components being extruded
-
- 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
- B29C2949/00—Indexing scheme relating to blow-moulding
- B29C2949/30—Preforms or parisons made of several components
- B29C2949/3056—Preforms or parisons made of several components having components being compression moulded
Landscapes
- Containers Having Bodies Formed In One Piece (AREA)
- Wrappers (AREA)
- Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
Description
本発明は、樹脂製中空成形容器およびその製造方法に関する。詳しくは、口栓部と少なくとも一部が発泡した中空の胴部とを有する樹脂製中空成形容器であって、口栓部が実質的に発泡していないことによって、口栓部のキャッピング性が良好な樹脂製中空成形容器と、この樹脂製中空成形容器を製造する方法に関する。 The present invention relates to a resin hollow molded container and a method for producing the same. Specifically, it is a resin-made hollow molded container having a cap portion and a hollow body portion that is at least partially foamed, and the cap portion is substantially not foamed, so that the capping property of the plug portion is reduced. The present invention relates to a good resin hollow molded container and a method for producing the resin hollow molded container.
樹脂製発泡成形品は、製品の軽量化、断熱性の向上、遮光性等の機能性の付与を目的として、各種分野での使用が拡大されている。 Resin foam-molded products have been used in various fields for the purpose of reducing the weight of the product, improving heat insulation, and imparting functionality such as light shielding properties.
従来、樹脂製発泡成形品を得る技術としては、例えば特許文献1に記載される方法がある。この方法は、具体的には、(1)高圧容器内で、熱可塑性樹脂に窒素や二酸化炭素などのガスを高圧、または超臨界状態で含浸させ、次いで、(2)ガスを含浸させた熱可塑性樹脂を高圧容器より取り出し、オイルバス等で熱可塑性樹脂のガラス転移温度(Tg)以上の温度まで昇温し、(3)核生成を誘発して気泡成長させることにより、微細気泡を有する発泡成形品を得るものである。 Conventionally, as a technique for obtaining a resin foam molded article, for example, there is a method described in Patent Document 1. Specifically, this method includes (1) impregnating a thermoplastic resin with a gas such as nitrogen or carbon dioxide in a high-pressure or supercritical state in a high-pressure vessel, and then (2) heat impregnated with the gas. The plastic resin is taken out from the high-pressure vessel, heated to a temperature equal to or higher than the glass transition temperature (Tg) of the thermoplastic resin with an oil bath or the like, and (3) foaming having fine bubbles by inducing nucleation and growing bubbles. A molded product is obtained.
樹脂製中空成形容器においても、同様に軽量化、断熱性の向上、遮光性の付与などを目的として発泡中空成形容器が採用されている。中空成形容器は、多くの場合、容器内部を密封するために、収容部となる中空の胴部(本体部)に対して口栓部を設け、口栓部にキャップを取り付けて密栓する構成とされる。しかし、発泡中空成形容器において、この口栓部も発泡成形部であると、発泡による膨張のために口栓部の寸法精度、形状精度が劣るものとなり、口栓部にキャップが嵌合しにくくなったり、またキャップが嵌合しても密封性が悪くなったりする。 Also in the resin hollow molded container, the foamed hollow molded container is similarly employed for the purpose of reducing the weight, improving the heat insulating property, and imparting the light shielding property. In many cases, the hollow molded container has a configuration in which a cap portion is provided for a hollow body portion (main body portion) serving as a housing portion and a cap is attached to the cap portion to seal the inside of the container. Is done. However, in a foamed hollow molded container, if this plug part is also a foamed part, the dimensional accuracy and shape accuracy of the plug part will be inferior due to expansion due to foaming, and it is difficult to fit the cap into the plug part. Even if the cap is fitted, the sealing performance is deteriorated.
そこで、特許文献2には発泡剤を含有する熱可塑性溶融樹脂を射出成形して、実質的に無発泡のプリフォームを得、このプリフォームの口栓部を除く部分を加熱して発泡を起こさせ、次いで加熱部分が軟化している内に、延伸ブロー成形することにより、口栓部が実質的に無発泡の容器を製造する方法が提案されている。しかしながら、特許文献2に記載の方法では、プリフォームの加熱時に、口栓部のみ加熱されないようにするための遮蔽板が必要であるが、また、遮蔽版を取り付けても完全には口栓部の加熱を防ぐことができず、このため口栓部で若干の発泡が起こり、口栓部の寸法精度、形状精度が悪いという問題がある。 Therefore, in Patent Document 2, a thermoplastic molten resin containing a foaming agent is injection-molded to obtain a substantially non-foamed preform, and the portion other than the plug portion of the preform is heated to cause foaming. Then, while the heated portion is softened, a method of manufacturing a container having a substantially non-foamed cap portion by stretch blow molding has been proposed. However, the method described in Patent Document 2 requires a shielding plate for preventing only the plug portion from being heated when the preform is heated, but the plug portion is completely attached even when the shielding plate is attached. Therefore, there is a problem that some foaming occurs in the plug portion and the dimensional accuracy and shape accuracy of the plug portion are poor.
なお、前述の特許文献1には、高圧または超臨界ガスを利用して樹脂発泡材料を得る方法が記載されているが、特許文献1には、このようにして中空成形容器を成形する場合の口栓部の発泡による寸法精度、形状精度の問題はもとより、そもそも中空成形容器の成形について全く触れられていない。
本発明は上記従来の問題点を解決し、中空の胴部が発泡部とされることにより、断熱性、遮光性等の機能性が付与された軽量樹脂製中空成形容器であって、口栓部が非発泡部又は低発泡部であることにより、口栓部の寸法精度、形状精度に優れ、キャッピングによる密封性が良好な樹脂製中空成形容器と、この樹脂製中空成形容器の製造方法を提供することを目的とする。 The present invention solves the above-mentioned conventional problems, and is a lightweight resin hollow molded container to which functions such as heat insulating properties and light shielding properties are imparted by forming a hollow body portion as a foamed portion. A resin hollow molded container having excellent dimensional accuracy and shape accuracy of the plug portion and having good sealing performance by capping, and a method for producing this resin hollow molded container The purpose is to provide.
本発明(請求項1)の樹脂製中空成形容器の製造方法は、ポリエチレンテレフタレートを含む原料樹脂を用いて口栓部を有する樹脂製中空成形容器のプリフォームを成形する工程と、該プリフォームを原料樹脂の軟化点以下の温度で超臨界状態にある加圧ガスと接触させて該プリフォームにガスを溶解させる工程と、ガスを溶解させたプリフォームを原料樹脂のガラス転移点以下の温度で常圧に戻す工程と、その後、プリフォームを加熱延伸する工程とを有する樹脂製中空成形容器の製造方法であって、前記原料樹脂は実質的に発泡剤を含有せず、かつ前記プリフォームにガスを溶解させる工程に先立って、前記プリフォームの口栓部を加熱結晶化させる工程を有し、結晶化後の口栓部の密度が1.35g/cm 3 以上であることを特徴とする。 The method for producing a resin hollow molded container according to the present invention (Claim 1 ) includes a step of molding a preform of a resin hollow molded container having a cap portion using a raw material resin containing polyethylene terephthalate , and the preform. Contacting the pressurized gas in a supercritical state at a temperature below the softening point of the raw material resin to dissolve the gas in the preform, and the preform in which the gas is dissolved at a temperature below the glass transition point of the raw material resin A process for producing a resin hollow molded container comprising a step of returning to normal pressure and a step of heating and stretching the preform, wherein the raw material resin does not substantially contain a foaming agent, and is applied to the preform. prior to the step of dissolving the gas, have a step of heating crystallized mouth portion of the preform, the density of the mouth portion after crystallization and wherein 1.35 g / cm 3 or more der Rukoto That.
請求項2の樹脂製中空成形容器の製造方法は、請求項1において、前記加圧ガスが炭酸ガスであることを特徴とする。 The method for producing a resin hollow molded container according to claim 2 is characterized in that, in claim 1 , the pressurized gas is carbon dioxide gas.
本発明(請求項3)の樹脂製中空成形容器はまた、上記本発明の樹脂製中空成形容器の製造方法で製造されたことを特徴とする。 The resin hollow molded container of the present invention (Claim 3 ) is also characterized by being manufactured by the above-described method for manufacturing a resin hollow molded container of the present invention.
本発明によれば、中空の胴部が発泡部とされることにより、断熱性、遮光性等の機能性が付与された軽量樹脂製中空成形容器であって、口栓部が非発泡部又は低発泡部であることにより、口栓部の寸法精度、形状精度に優れ、キャッピングによる密封性が良好な樹脂製中空成形容器が提供される。 According to the present invention, it is a lightweight resin hollow molded container to which functions such as heat insulation and light shielding properties are imparted by making the hollow body part a foamed part, and the plug part is a non-foamed part or By being a low foaming part, the resin hollow molding container which is excellent in the dimensional accuracy and shape precision of the stopper part, and has favorable sealing performance by capping is provided.
以下に本発明の樹脂製中空成形容器及びその製造方法の実施の形態を、本発明の樹脂製中空成形容器の製造方法に従って詳細に説明するが、以下に記載する構成要件の説明は、本発明の実施態様の代表例であり、これらの内容に本発明は限定されるものではない。 Hereinafter, embodiments of the resin hollow molded container and the manufacturing method thereof according to the present invention will be described in detail according to the method of manufacturing the resin hollow molded container according to the present invention. It is a typical example of this embodiment, and the present invention is not limited to these contents.
[樹脂製中空成形容器の製造方法]
[1]原料樹脂
本発明の樹脂製中空成形容器を構成する樹脂種は、熱可塑性樹脂であり、その熱可塑性樹脂としては、芳香族ポリエステル、脂肪族ポリエステル、脂環式ポリエステルなどのポリエステル系樹脂などが挙げられる。これらは、1種を単独で用いても良く、2種以上を混合して用いても良い。
[Method for producing resin hollow molded container]
[1] Resin species constituting the resin hollow molded container of starting resin this invention is a thermoplastic resin, as its thermoplastic resin, Fang aromatic polyesters, aliphatic polyesters, polyester-based, such as the cycloaliphatic polyester etc. tree butter, and the like. These may be used alone or in combination of two or more.
中でも、結晶性樹脂が、樹脂製中空成形容器を延伸ブロー成形する際の延伸効果により強度向上効果が発揮されるため好ましく、ポリエステル系樹脂がさらに好ましく、ポリエチレンテレフタレートが特に好ましい。 Among them, the crystalline resin is preferable because the effect of improving the strength is exhibited by the stretching effect when the hollow resin molded container is stretch blow molded, the polyester resin is more preferable, and the polyethylene terephthalate is particularly preferable.
従って、本発明の樹脂製中空成形容器の製造方法においては、原料樹脂としてポリエステル系樹脂を用いるのが好ましく、ポリエチレンテレフタレートを用いるのがより好ましい。 Therefore, in the method for producing a resin hollow molded container of the present invention, it is preferable to use a polyester-based resin as the raw material resin, and more preferably to use polyethylene terephthalate.
本発明に係る原料樹脂には、本発明の効果を損なわない範囲で、必要に応じて各種樹脂添加剤を配合することができる。樹脂添加剤としては、例えば、発泡核剤、顔料・染料などの着色剤、熱安定剤、光安定剤、離型剤、防腐剤、紫外線吸収剤、可塑剤、滑剤、難燃剤、導電性付与剤、帯電防止剤、結晶核剤などが挙げられる。これら樹脂添加剤は、1種を単独で用いても良く、2種以上を併用しても良い。 In the raw material resin according to the present invention, various resin additives can be blended as necessary within a range not impairing the effects of the present invention. Examples of resin additives include foam nucleating agents, colorants such as pigments and dyes, heat stabilizers, light stabilizers, mold release agents, preservatives, ultraviolet absorbers, plasticizers, lubricants, flame retardants, and conductivity imparting. Agents, antistatic agents, crystal nucleating agents and the like. These resin additives may be used alone or in combination of two or more.
ただし、本発明の樹脂製中空成形容器の製造方法において、原料樹脂としては発泡剤を実質的に含有しないものが用いられる。 However, in the method for producing a resin hollow molded container according to the present invention, a raw material resin that does not substantially contain a foaming agent is used.
ここで、発泡剤とは樹脂成形体中に固定された気泡群を構成するために使用する薬剤等の総称であり、例えば、気体や揮発性の液体、加熱により分解してガスを発生する無機または有機化合物等が使われる。より具体的には、窒素、炭酸ガス、ヘリウム等の不活性ガス、プロパン、ブタン、ペンタン、ヘキサン等の飽和炭化水素、テトラフロロエタン、フレオン(商品名)等のハロゲン化炭化水素などの物理発泡剤、炭酸ナトリウム、重炭酸ナトリウム等の無機塩、クエン酸ナトリウムなどの有機塩、アゾジカルボンアミド、ヒドラゾンカルボンアミド等のアゾ化合物およびその塩、5−フェニルテトラゾール等のテトラゾール化合物およびその塩などの化学発泡剤が挙げられる。 Here, the foaming agent is a general term for chemicals used to form a group of bubbles fixed in a resin molded body, for example, a gas or a volatile liquid, an inorganic that decomposes by heating to generate a gas. Or an organic compound etc. are used. More specifically, physical foams such as inert gases such as nitrogen, carbon dioxide and helium, saturated hydrocarbons such as propane, butane, pentane and hexane, halogenated hydrocarbons such as tetrafluoroethane and freon (trade name) Chemicals such as chemicals, inorganic salts such as sodium carbonate and sodium bicarbonate, organic salts such as sodium citrate, azo compounds such as azodicarbonamide and hydrazonecarbonamide and their salts, tetrazole compounds such as 5-phenyltetrazole and their salts A foaming agent is mentioned.
本発明において、発泡剤を実質的に含有しない原料樹脂とは、原料樹脂の調製に当たり、積極的に発泡剤を添加混合していない原料樹脂であり、原料樹脂の調製工程において不可避的に混入するごく微量のガスや、残留溶剤等は本発明に係る原料樹脂中の発泡剤には該当しない。また、前述の発泡核剤としては、例えばガラス、鉱物質材料等が挙げられ、これらが核となって発泡開始を促進するものであり、発泡核剤自身が発泡するのではないという点において発泡剤とは異なる。 In the present invention, the raw material resin substantially not containing a foaming agent is a raw material resin not actively mixed with a foaming agent in preparation of the raw material resin, and is inevitably mixed in the preparation step of the raw material resin. A very small amount of gas, residual solvent, or the like does not correspond to the foaming agent in the raw material resin according to the present invention. Further, examples of the above-mentioned foam nucleating agent include glass, mineral materials, etc., and these serve as nuclei to promote the start of foaming, and the foam nucleating agent itself does not foam. It is different from the agent.
[2]プリフォームの成形
本発明の樹脂製中空成形容器の製造方法においては、まず上記原料樹脂を用いて口栓部を有する樹脂製中空成形容器のプリフォーム(先駆体)を成形する。プリフォームの成形方法としては、例えば原料樹脂の射出成形により口栓部付の試験管状のプリフォームを成形する方法、原料樹脂をチューブ状に押出成形し、これを切断して口栓部および底部を加熱プレス成形により形成する方法などが挙げられる。なお、口栓部は通常、キャッピング時に上方から受ける圧力を支えるため、或いは搬送時に使用するためにサポートリングを有する。このサポートリングは、プリフォームを成形する時に使用する射出成形金型やプレス成形金型に、サポートリングに相当する空隙を設けておくことにより設けることができる。
[2] Molding of preform In the method for producing a resin hollow molded container according to the present invention, first, a preform (precursor) of a resin hollow molded container having a plug portion is molded using the raw material resin. The preform molding method includes, for example, a method of molding a test tubular preform with a plug portion by injection molding of a raw material resin, an extrusion molding of the raw material resin into a tube shape, and cutting this into a plug portion and a bottom portion. And the like may be formed by hot press molding. Note that the plug portion usually has a support ring for supporting the pressure received from above during capping or for use during transportation. This support ring can be provided by providing a gap corresponding to the support ring in an injection mold or press mold used when molding a preform.
[3]口栓部の加熱結晶化
次いで、得られたプリフォームの口栓部を加熱して結晶化させる。即ち、プリフォームの口栓部のみをその原料樹脂の結晶化温度以上に加熱して結晶化させる。
[3] Heating and Crystallization of Mouth Portion Next, the plug portion of the preform obtained is heated and crystallized. That is, only the plug portion of the preform is heated to a temperature equal to or higher than the crystallization temperature of the raw material resin for crystallization.
この加熱温度は、樹脂の結晶化温度より0〜20℃高い温度、例えば、原料樹脂がポリエチレンテレフタレートを含むものであれば170〜190℃であることが好ましい。この結晶化温度が低過ぎると十分に結晶化させることができず、高過ぎると樹脂の劣化を招く。加熱時間は、口栓部が結晶化される時間であれば良いが、通常2〜5分程度である。 This heating temperature is preferably 0 to 20 ° C. higher than the crystallization temperature of the resin, for example, 170 to 190 ° C. if the raw material resin contains polyethylene terephthalate. If the crystallization temperature is too low, sufficient crystallization cannot be achieved, and if it is too high, the resin is deteriorated. The heating time may be a time during which the plug portion is crystallized, but is usually about 2 to 5 minutes.
なお、プリフォームの口栓部のみを加熱する方法としては、具体的にはアルミニウム製の筒状のポットで、プリフォームのサポートリングより下の部分を、熱が加わらないように遮蔽し、赤外線ヒーターを用いて口栓部のみを加熱すれば良い。 In addition, as a method of heating only the plug portion of the preform, specifically, a portion of the aluminum pot that is below the support ring of the preform is shielded so that heat is not applied, and infrared rays are applied. What is necessary is just to heat only a plug part using a heater.
このようにして口栓部の結晶化を行うことにより、原料樹脂としてポリエチレンテレフタレートを用いた場合にあっては、結晶化後の口栓部の密度が1.35g/cm3以上、特に1.36g/cm3以上、とりわけ1.37g/cm3以上となることが好ましい。結晶化後の口栓部の密度が1.35g/cm3未満であると、後工程のプリフォームにガスを溶解させる工程で、プリフォームの胴部だけでなく、口栓部にもガスが溶解し易くなるため、その後の工程で口栓部の発泡が起こり、本発明の目的を達成し得ない。なお、結晶化後の口栓部の密度の上限は通常1.42g/cm3である。 By crystallization of the plug part in this manner, when polyethylene terephthalate is used as the raw material resin, the density of the plug part after crystallization is 1.35 g / cm 3 or more, particularly 1. It is preferably 36 g / cm 3 or more, particularly 1.37 g / cm 3 or more. When the density of the plug portion after crystallization is less than 1.35 g / cm 3 , the gas is dissolved not only in the trunk portion of the preform but also in the plug portion in the step of dissolving the gas in the preform of the subsequent step. Since it becomes easy to melt | dissolve, foaming of a plug part occurs in a subsequent process and the objective of this invention cannot be achieved. In addition, the upper limit of the density of the plug portion after crystallization is usually 1.42 g / cm 3 .
[4]プリフォームへのガスの溶解
口栓部を結晶化させたプリフォームは、次いで、原料樹脂の軟化点以下の温度で加圧ガスと接触させてプリフォームにガスを溶解させる。具体的には、プリフォームを耐圧容器に入れ、この耐圧容器にガスを加圧、注入して、プリフォームと加圧ガスとを接触させることによりプリフォームにガスを溶解させる。このガスの溶解工程においては、プリフォームの胴部にのみガスが溶解し、結晶化された口栓部には実質的にガスは溶解しない。
[4] Dissolution of gas in preform The preform crystallized from the plug portion is then brought into contact with a pressurized gas at a temperature equal to or lower than the softening point of the raw material resin to dissolve the gas in the preform. Specifically, the preform is placed in a pressure vessel, gas is pressurized and injected into the pressure vessel, and the preform is brought into contact with the pressurized gas to dissolve the gas in the preform. In this gas dissolving step, the gas is dissolved only in the body portion of the preform, and the gas is not substantially dissolved in the crystallized plug portion.
(1)温度条件
ガスをプリフォームに溶解させる際の温度は、常温(即ち10〜25℃)から原料樹脂の軟化点以下の温度範囲で設定される。好ましくは常温以上で原料樹脂のガラス転移点以下である。この温度が常温より低いと、ガスがプリフォームに溶解し難く、温度が高すぎるとプリフォームの形が崩れるので好ましくない。
(1) Temperature conditions The temperature at which the gas is dissolved in the preform is set in a temperature range from normal temperature (that is, 10 to 25 ° C.) to the softening point of the raw resin. Preferably it is above normal temperature and below the glass transition point of the raw material resin. If this temperature is lower than normal temperature, the gas is difficult to dissolve in the preform, and if the temperature is too high, the shape of the preform is destroyed, which is not preferable.
なお、本発明において軟化点とは、JISK7121に準拠し、示差走査熱量測定器(DSC)によって測定される融解ピーク温度(Tm)を意味し、ガラス転移点とは、JISK7121に準拠して測定されるガラス転移温度(Tg)を意味する。ポリエチレンテレフタレートの場合、一般的にはTmは約258℃、Tgは約80℃である。 In the present invention, the softening point means a melting peak temperature (Tm) measured by a differential scanning calorimeter (DSC) in accordance with JISK7121, and the glass transition point is measured in accordance with JISK7121. Glass transition temperature (Tg). In the case of polyethylene terephthalate, Tm is generally about 258 ° C. and Tg is about 80 ° C.
従って、原料樹脂としてポリエチレンテレフタレートを用いた場合、このガス溶解工程の温度条件は10〜80℃程度であることが好ましい。 Therefore, when polyethylene terephthalate is used as the raw material resin, the temperature condition of this gas dissolving step is preferably about 10 to 80 ° C.
(2)圧力条件
ガスの溶解工程で、ガスを加圧するのは、ガスのプリフォームへの溶解量を多くするためである。ガスの圧力が高いほど、プリフォームへの溶解量を多くすることができるが、装置が大掛かりになるので好ましくない。従って、圧力条件は、常圧を超え、40MPa以下の範囲、例えば5〜35MPaの範囲で設定するのが好ましい。
(2) Pressure condition The reason for pressurizing the gas in the gas dissolving step is to increase the amount of gas dissolved in the preform. The higher the gas pressure, the larger the amount dissolved in the preform, but this is not preferable because the apparatus becomes large. Therefore, the pressure condition is preferably set in a range exceeding normal pressure and 40 MPa or less, for example, in a range of 5 to 35 MPa.
(3)接触時間
プリフォームとガスとの接触時間は、使用する原料樹脂の種類、プリフォームの大きさ、プリフォームの肉厚(プリフォームの中空の胴部を構成する壁の厚さ)、用いるガスの種類、ガスを接触させる際の圧力、ガスを接触させる際の温度、最終的に得ようとする樹脂製中空成形容器の発泡部分の形態(発泡倍率、気泡の密度、気泡の大きさ)などに応じて、数秒間〜数時間の範囲で適宜設定することができる。
(3) Contact time The contact time between the preform and the gas is the type of raw material resin used, the size of the preform, the thickness of the preform (the thickness of the wall constituting the hollow body of the preform), The type of gas used, the pressure when contacting the gas, the temperature when contacting the gas, the form of the foamed part of the hollow resin molded container to be finally obtained (foaming ratio, bubble density, bubble size) ) And the like can be appropriately set within a range of several seconds to several hours.
(4)ガス種
用いるガスは、原料樹脂に対して不活性なガスであることが好ましい。ここで原料樹脂に対して不活性なガスとは、当該ガスを原料樹脂と接触させることによって、原料樹脂の物性を低下させたり、化学的構造を変化させたりしないガスのことをいう。
(4) Gas type The gas used is preferably a gas inert to the raw material resin. Here, the gas inert to the raw material resin refers to a gas that does not lower the physical properties of the raw material resin or change the chemical structure by bringing the gas into contact with the raw material resin.
ガスの具体例としてはアルゴン、窒素、炭酸ガスなどが挙げられ、なかでも炭酸ガスが後述の超臨界状態で容易に取り扱えるなどの観点から好ましい。 Specific examples of the gas include argon, nitrogen, carbon dioxide, and the like. Among these, carbon dioxide is preferable from the viewpoint that it can be easily handled in a supercritical state described later.
(5)ガスの状態
ガスは、加圧された気体状態であっても良いが、亜臨界状態や超臨界状態が好ましく、超臨界状態でプリフォームに接触させるのが特に好ましい。超臨界状態とは、臨界温度、臨界圧力以上の状態を意味する。例えば、二酸化炭素の場合、超臨界状態とは、温度は30℃以上で圧力は7.3MPa以上の状態である。超臨界状態のガスは、液体状態のものよりも粘度が低く、かつ、樹脂内部へ拡散しやすいという特性を有し、また気体状態よりも密度が大きいことから、大量にかつ速やかにガスをプリフォームに溶解させることができるので好ましい。
(5) Gas State Although the gas may be in a pressurized gas state, a subcritical state or a supercritical state is preferable, and it is particularly preferable to contact the preform in the supercritical state. The supercritical state means a state above the critical temperature and critical pressure. For example, in the case of carbon dioxide, the supercritical state is a state where the temperature is 30 ° C. or higher and the pressure is 7.3 MPa or higher. The gas in the supercritical state has a property that it has a lower viscosity than that in the liquid state and easily diffuses into the resin, and has a higher density than the gas state. This is preferable because it can be dissolved in the reform.
従って、原料樹脂としてポリエチレンテレフタレートを用いたプリフォームに二酸化炭素を溶解させる場合、特に10〜30℃で7.3〜40MPa程度の条件でプリフォームに二酸化炭素を接触させることが好ましい。 Therefore, when carbon dioxide is dissolved in a preform using polyethylene terephthalate as a raw material resin, it is preferable that carbon dioxide is brought into contact with the preform under conditions of about 7.3 to 40 MPa at 10 to 30 ° C.
(6)ガスの溶解量
プリフォームへのガスの溶解量が多いほど、発泡倍率を高くし、気泡を多く形成することができる。プリフォームへ溶解するガスは、プリフォームの胴部を構成する壁の表層部分(即ち、壁面近傍部分)ほど溶解量が多く、内層部分(壁内部)にゆくほど溶解量が少なくなる。そのため、プリフォームには、その壁の厚さ方向において、ガス溶解量に傾斜ができるが、ガスは、プリフォームの壁の厚さ方向の中心部に達しないように調節するのが好ましい。これは、後工程で壁中央部に非発泡層を形成して、得られる樹脂製中空成形容器の強度を確保するためである。
(6) Amount of dissolved gas The larger the amount of dissolved gas in the preform, the higher the expansion ratio and the more bubbles can be formed. The amount of the gas dissolved in the preform increases as the surface layer portion of the wall (that is, the portion in the vicinity of the wall surface) constituting the body portion of the preform increases, and decreases as it moves toward the inner layer portion (inside the wall). Therefore, the amount of dissolved gas in the preform can be inclined in the thickness direction of the wall, but it is preferable to adjust the gas so that it does not reach the center in the thickness direction of the wall of the preform. This is because a non-foamed layer is formed at the center of the wall in a later step to ensure the strength of the resulting resin hollow molded container.
ガスがプリフォームの壁の中心層に達しないようにする方法の例としては、ガスの溶解距離をx、プリフォームの壁内でのガスの拡散係数をD、溶解時間をtとするとき、x=√(Dt)と表されるので、xがプリフォームの壁の表面から厚さ方向の中心部(即ち、壁の肉厚の1/2)よりも小さくなるようにtを設定する方法が挙げられるが、実験により好適な時間を予め求めておくことも可能である。 As an example of a method for preventing the gas from reaching the center layer of the preform wall, when the dissolution distance of the gas is x, the diffusion coefficient of the gas within the preform wall is D, and the dissolution time is t, Since x = √ (Dt), a method of setting t so that x is smaller than the center portion in the thickness direction from the surface of the preform wall (that is, 1/2 of the wall thickness). However, it is also possible to obtain a suitable time in advance by experiments.
なお、ガスの溶解量は、得られる樹脂製中空成形容器の発泡層の形態(発泡倍率、気泡の密度、気泡の大きさ)などに影響するので、樹脂製中空成形容器を工業的に製造する際には、予め実験によって、プリフォームへのガスの溶解工程における最適条件を確認して製造条件を設定するのが好ましい。 In addition, since the amount of dissolved gases affects the form of the foamed layer (foaming ratio, bubble density, bubble size) of the resulting resin hollow molded container, the resin hollow molded container is manufactured industrially. In this case, it is preferable to set the manufacturing conditions by confirming the optimum conditions in the process of dissolving the gas in the preform by experiments.
[5]プリフォームの降圧
プリフォームを加圧ガスと接触させてガスを溶解させた後は、原料樹脂のガラス転移点以下の温度で脱圧して常圧に戻す。この工程において、プリフォームの温度が原料樹脂のガラス転移点よりも高いと、降圧工程で発泡が起こることがあり、好ましくない。原料樹脂としてポリエチレンテレフタレートを用いた場合、この降圧工程の温度条件は10〜70℃であることが好ましい。
[5] Depressurization of preform After the preform is brought into contact with the pressurized gas to dissolve the gas, the preform is depressurized at a temperature not higher than the glass transition point of the raw material resin and returned to normal pressure. In this step, if the temperature of the preform is higher than the glass transition point of the raw material resin, foaming may occur in the step-down step, which is not preferable. When polyethylene terephthalate is used as the raw material resin, the temperature condition of the pressure-lowering step is preferably 10 to 70 ° C.
なお、降圧速度については特に制限はないが、降圧速度が遅いと常圧に戻すのに長時間を要する。一方、降圧速度を速くしようとすると、脱圧用配管を太くする必要がある等の理由から、5〜20MPa/分程度の降圧速度とすることが好ましい。 Although there is no particular limitation on the step-down speed, it takes a long time to return to normal pressure when the step-down speed is slow. On the other hand, when trying to increase the pressure reduction speed, it is preferable to set the pressure reduction speed at about 5 to 20 MPa / min because the decompression pipe needs to be thickened.
[6]プリフォームの加熱延伸
上記降圧後は、ガスが溶解したプリフォームを加熱延伸、即ち延伸ブロー成形して樹脂製中空成形容器を得る。
[6] Heat stretching of preform After the pressure reduction, the preform in which the gas is dissolved is heat stretched, that is, stretch blow molded to obtain a resin hollow molded container.
このときの加熱温度は、原料樹脂のガラス転移点以上とする。この温度が原料樹脂のガラス転移点未満では延伸成形を行うことができないが、過度に高いと樹脂の劣化を招く。原料樹脂としてポリエチレンテレフタレートを用いた場合、この延伸ブロー成形の温度は90〜110℃であることが好ましい。 The heating temperature at this time is not less than the glass transition point of the raw material resin. If this temperature is less than the glass transition point of the raw material resin, stretch molding cannot be performed, but if it is too high, the resin will deteriorate. When polyethylene terephthalate is used as the raw material resin, the stretch blow molding temperature is preferably 90 to 110 ° C.
この加熱延伸において、ガスが溶解したプリフォームの胴部において発泡が起こり発泡層が形成される。一方、実質的にガスが溶解していない口栓部では発泡は起こらない。 In this heat stretching, foaming occurs in the body portion of the preform in which the gas is dissolved, and a foam layer is formed. On the other hand, foaming does not occur in the plug portion where the gas is not substantially dissolved.
また、前述の如く、プリフォームへのガスの溶解量は、プリフォームの壁の厚さ方向で傾斜しており、表層側で多く、内層側で少ない。特に本発明では、好ましくは胴部の厚さ方向の中央部分においてガスが溶解していない部分を形成するようにガスの溶解を行う。そのため、この加熱延伸で得られる樹脂製中空成形容器は、胴部において、肉厚方向の中央部分が非発泡層でその両側の表層部分に発泡層を有する層状構造であることが好ましい。ここで、中央部の非発泡層の厚さは前述の如く、プリフォームへのガスの溶解量、即ち溶解条件を調節することにより容易に制御することができる。 Further, as described above, the amount of gas dissolved in the preform is inclined in the thickness direction of the preform wall, and is large on the surface layer side and small on the inner layer side. In particular, in the present invention, the gas is preferably dissolved so as to form a portion where the gas is not dissolved in the central portion of the body portion in the thickness direction. Therefore, it is preferable that the resin hollow molded container obtained by this heat-stretching has a layered structure in which the central portion in the thickness direction is a non-foamed layer and the foamed layers are formed on the surface layers on both sides of the body portion. Here, as described above, the thickness of the central non-foamed layer can be easily controlled by adjusting the amount of gas dissolved in the preform, that is, the dissolution conditions.
なお、胴部の厚さ方向の最表層は発泡後破泡して非発泡層となることがある。また、胴部に形成される発泡層の泡の大きさは、厚さ方向において中央側の方が大きく表層側が小さくなる傾向にある。従って、本発明で得られる樹脂製中空成形容器は、通常、その胴部において、その厚さ方向に、一方の最表層の非発泡層/発泡層/中心層の非発泡層/発泡層/他方の最表層の非発泡層、の順のサンドイッチ構造を有し、発泡層の気泡径が中心層側から表層側へ向けて次第に大きくなるものとなる。 In addition, the outermost surface layer in the thickness direction of the body portion may break after foaming to become a non-foamed layer. Further, the foam size of the foam layer formed on the body portion tends to be larger on the center side and smaller on the surface layer side in the thickness direction. Therefore, the resin hollow molded container obtained by the present invention is usually one of the outermost layer non-foamed layer / foamed layer / central layer non-foamed layer / foamed layer / the other in the thickness direction in the body portion. The outermost non-foamed layer has a sandwich structure in this order, and the bubble diameter of the foamed layer gradually increases from the center layer side to the surface layer side.
なお、本発明において非発泡層とは、中空成形容器の断面を走査型電子顕微鏡によって60倍に拡大して観察した際、平均気泡径が0.1μm未満の気泡しか観察されない層を言い、発泡層とは、中空成形容器の断面を走査型電子顕微鏡によって60倍に拡大して観察した際、平均気泡径が0.1μm以上の気泡が観察される層を言う。 In the present invention, the non-foamed layer refers to a layer in which only bubbles having an average bubble diameter of less than 0.1 μm are observed when the cross section of the hollow molded container is observed with a scanning electron microscope magnified 60 times. The layer refers to a layer in which bubbles having an average bubble diameter of 0.1 μm or more are observed when the cross section of the hollow molded container is observed with a scanning electron microscope magnified 60 times.
[樹脂製中空成形容器]
次に、本発明の樹脂製中空成形容器について説明する。
[Hollow resin molded container]
Next, the resin hollow molded container of the present invention will be described.
本発明の樹脂製中空成形容器は、口栓部と中空の胴部とを有する樹脂製中空成形容器において、該胴部の少なくとも一部が発泡部分であり、かつ口栓部の発泡倍率が胴部の発泡部分の発泡倍率より低いか、もしくは口栓部が実質的に発泡していないことを特徴とするものである。 The resin hollow molded container according to the present invention is a resin hollow molded container having a cap portion and a hollow barrel portion, wherein at least a part of the barrel portion is a foamed portion, and the foaming ratio of the plug portion is a barrel. It is characterized by being lower than the expansion ratio of the foamed part of the part, or the plug part being substantially not foamed.
この樹脂製中空成形容器は、上述の本発明の樹脂製中空成形容器の製造方法により製造されたものであることが好ましいが、本発明の樹脂製中空成形容器の製造方法に限らず、熱可塑性樹脂を原料として射出成形や押出成形により口栓部を有する樹脂製中空成形容器のプリフォームを成形し、このプリフォームの胴部のみに加圧ガスを接触させるなどによりガスを含浸・溶解させてから加熱発泡させるとともに延伸ブローして中空成形容器とすることにより得ることもできる。 The resin hollow molded container is preferably manufactured by the above-described method for manufacturing a resin hollow molded container according to the present invention, but is not limited to the method for manufacturing a resin hollow molded container according to the present invention. Resin is used as a raw material to form a preform of a resin hollow molding container having a cap portion by injection molding or extrusion molding, and the gas is impregnated and dissolved by contacting a pressurized gas only to the body of the preform. It can also be obtained by heating and foaming and stretching and blowing to form a hollow molded container.
本発明の樹脂製中空成形容器の口栓部は胴部の発泡部分の発泡倍率より低い発泡倍率であるかもしくは実質的に発泡していない。この口栓部の発泡倍率が胴部の発泡部分の発泡倍率以上であると口栓部の寸法精度及び形状精度が劣ることにより、キャップの嵌合が悪くなり、容器の密栓性が悪くなる。この口栓部は実質的に発泡していないことが好ましい。 The plug portion of the resin hollow molded container of the present invention has a foaming ratio lower than the foaming ratio of the foamed portion of the trunk or is not substantially foamed. When the expansion ratio of the plug portion is equal to or higher than the expansion ratio of the foamed portion of the body portion, the dimensional accuracy and shape accuracy of the plug portion are inferior, so that the fitting of the cap is deteriorated and the tightness of the container is deteriorated. It is preferable that the plug portion is not substantially foamed.
ここで発泡倍率とは、中空成形容器のプリフォームにおける任意の部分の密度(D1)と、成形後の樹脂製中空成形容器の前記プリフォームにおける当該任意の部分に相当する部分の密度(D2)を測定し、得られた密度D1を密度D2で除した値のことをいう。実質的に発泡していないとは、このD1/D2の値が例えば1〜1.05程度であることをいう。 Here, the expansion ratio is the density (D1) of an arbitrary part in the preform of the hollow molded container and the density (D2) of the part corresponding to the arbitrary part of the preform of the molded hollow resin container after molding. Is a value obtained by dividing the obtained density D1 by the density D2. “Not substantially foamed” means that the value of D1 / D2 is, for example, about 1 to 1.05.
また、本発明の樹脂製中空成形容器は、ポリエステル系樹脂、中でもポリエチレンテレフタレートよりなることが好ましく、樹脂がポリエチレンテレフタレートである場合、その口栓部の密度は1.35g/cm3以上であることが好ましい。口栓部の密度が1.35g/cm3未満であるとポリエチレンテレフタレートの結晶化度が低く、熱に対して寸法安定性が劣る傾向となり、得られる樹脂製中空成形容器の寸法精度、形状精度が劣る場合がある。 Moreover, the resin hollow molded container of the present invention is preferably made of a polyester-based resin, particularly polyethylene terephthalate. When the resin is polyethylene terephthalate, the density of the plug portion is 1.35 g / cm 3 or more. Is preferred. If the density of the plug portion is less than 1.35 g / cm 3 , the degree of crystallinity of polyethylene terephthalate tends to be low and the dimensional stability tends to be inferior to heat, and the dimensional accuracy and shape accuracy of the resulting resin hollow molded container May be inferior.
また、本発明の樹脂製中空成形容器の胴部の発泡部分はその壁の厚さ方向に発泡層と非発泡層との層状構造を有し、表層側が発泡層で厚さ方向の中央部分が非発泡層であることが好ましい。即ち、発泡層は容器の軽量化、断熱性等の機能性の向上等に寄与し、一方、非発泡層は、容器の強度や耐熱性保持に寄与する。樹脂製中空成形容器の胴部を構成する壁が、厚さ方向の中央部分が非発泡層でその両側の表層部分が発泡層で構成された層状構造であると、十分な強度と耐熱性を有し、かつ、軽量で断熱性等の機能性にも優れた樹脂製中空成形容器が得られるため好ましい。 Further, the foamed portion of the body portion of the resin hollow molded container of the present invention has a layered structure of a foamed layer and a non-foamed layer in the thickness direction of the wall, the surface layer side is a foamed layer and the central portion in the thickness direction is A non-foamed layer is preferred. That is, the foamed layer contributes to the weight reduction of the container, the improvement of the functionality such as heat insulation, and the like, while the non-foamed layer contributes to the strength and heat resistance retention of the container. When the wall constituting the body of the resin hollow molded container has a layered structure in which the central portion in the thickness direction is a non-foamed layer and the surface layer portions on both sides are formed of a foamed layer, sufficient strength and heat resistance can be obtained. It is preferable because a resin-made hollow molded container having a light weight and excellent functionality such as heat insulation can be obtained.
この場合、この層状構造を形成する発泡層と非発泡層の厚さは、樹脂製中空成形容器の要求特性に応じて任意に設定することができる。 In this case, the thicknesses of the foamed layer and the non-foamed layer forming this layered structure can be arbitrarily set according to the required characteristics of the resin hollow molded container.
例えば、中心層の非発泡層を厚くすることによって、強度、耐熱性を高めることができる。また、中心層の非発泡層を薄くし表層の発泡層を厚くすることにより、軽量化を図り、断熱性を向上させることができる。断熱性を向上させた樹脂製中空成形容器を得るには、胴部の壁部の全体厚さの30%以上を発泡層とするのが好ましい。また、耐熱性を向上させるには、樹脂がポリエチレンテレフタレートのように結晶性樹脂の場合は、結晶化度が高いほうが好ましく、結晶化度は5%以上、さらに10%以上がより好ましい。また、耐熱性を向上させるには、中心層の非発泡層の厚さを胴部の壁部の全体厚さの10〜90%の範囲、特に20〜50%の範囲とするのが好ましい。 For example, the strength and heat resistance can be increased by increasing the thickness of the non-foamed layer of the center layer. Further, by reducing the thickness of the non-foamed layer of the center layer and the foamed layer of the surface layer, the weight can be reduced and the heat insulation can be improved. In order to obtain a resin-made hollow molded container with improved heat insulation, it is preferable to use 30% or more of the total thickness of the wall portion of the body portion as the foam layer. In order to improve heat resistance, when the resin is a crystalline resin such as polyethylene terephthalate, it is preferable that the crystallinity is high, and the crystallinity is 5% or more, and more preferably 10% or more. Moreover, in order to improve heat resistance, it is preferable that the thickness of the non-foamed layer of the center layer is in the range of 10 to 90%, particularly in the range of 20 to 50% of the total thickness of the wall portion of the trunk portion.
以下に実施例及び比較例を挙げて本発明をより具体的に説明するが、本発明はその要旨を超えない限り、以下の実施例に限定されるものではない。 Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the following examples as long as the gist thereof is not exceeded.
なお、以下において、プリフォームの表面温度及び口栓部の表面温度の測定は、放射率を0.90に設定した(株)キーエンス社製非接触ハンディ温度計「IT2−80」を使用して、加熱処理後の表面温度を約0.3mの距離から測定することにより行った。 In the following, measurement of the surface temperature of the preform and the surface temperature of the plug portion is performed using a non-contact handy thermometer “IT2-80” manufactured by Keyence Corporation with an emissivity of 0.90. The surface temperature after the heat treatment was measured from a distance of about 0.3 m.
(実施例1)
ポリエチレンテレフタレート(日本ユニペット社製「RT553」、ガラス転移点(Tg)80℃)を原料樹脂として、以下の方向で樹脂製中空成形容器を成形した。
Example 1
A resin hollow molding container was molded in the following direction using polyethylene terephthalate (“RT553” manufactured by Nihon Unipet Co., Ltd., glass transition point (Tg) 80 ° C.) as a raw material resin.
まず、原料ポリエチレンテレフタレート約5キログラムを縦×横×高さが概略300×500×80mmのステンレス製バットに平坦に入れ、ヤマト科学社製真空乾燥機「DP63」を用い、145℃で約12時間の真空乾燥を実施した。真空乾燥が終了した原料樹脂を成形中の吸湿を防ぐ目的で(株)カワタ社製樹脂乾燥機「チャレンジャーD−50」に投入し、135℃で保持しながらプリフォームの射出成形を実施した。 First, about 5 kilograms of raw material polyethylene terephthalate is placed flat in a stainless steel bat measuring approximately 300 × 500 × 80 mm in length × width × height, and about 12 hours at 145 ° C. using a vacuum dryer “DP63” manufactured by Yamato Scientific Co., Ltd. Was vacuum dried. For the purpose of preventing moisture absorption during molding, the raw material resin after the vacuum drying was put into a resin dryer “Challenger D-50” manufactured by Kawata Co., Ltd., and a preform was injection molded while being held at 135 ° C.
射出成形は多層延伸ブロー機の射出成形機(日精エー・エス・ビー社製、型式:ASB−50TH)を使用し、シリンダー設定温度及びホットランナー設定温度を280℃とし、射出1.5秒、圧力保持16.5秒、冷却10秒、金型温度15℃の条件下、サポートリング付口栓部を有する、長さ100mm、外径25mm、胴部壁厚さ4mmのプリフォーム(内部容量30ml)を作成した。このプリフォームを目視にて確認したところ、気泡は全く認められなかった。 Injection molding uses a multilayer stretch blow machine injection molding machine (manufactured by Nissei ASB Co., model: ASB-50TH), the cylinder set temperature and the hot runner set temperature are 280 ° C., and the injection is 1.5 seconds. A preform having a length of 100 mm, an outer diameter of 25 mm, and a body wall thickness of 4 mm, having a stopper part with a support ring under the conditions of pressure holding of 16.5 seconds, cooling of 10 seconds and mold temperature of 15 ° C. (internal capacity of 30 ml) )created. When this preform was visually confirmed, no bubbles were observed.
得られたプリフォームのサポートリングより下の部分を、アルミ製の筒状ポットに挿入することにより、口栓部のみが加熱されるように構成された口栓部結晶化機(日精エー・エス・ビー機械社製「CM−2000」)を用い、室温で投入したプリフォームの口栓部表面の加熱終了直後の温度が183±2℃となるようにヒーター出力を調整し、生産速度を1800本/時間として口栓部を結晶化した。このとき得られた結晶化口栓部の密度を、口栓部を約5mm四方に切断したサンプルと、臭化ナトリウムの水/エタノール水溶液で作成した密度勾配管を用いて23℃で測定した。その結果、口栓部天面の密度が1.385g/cm3、口栓部のサポートリング部の密度が1.360g/cm3であった。 The plug crystallizer (Nissei A.S. Co., Ltd.) was constructed so that only the plug part was heated by inserting the part below the support ring of the obtained preform into an aluminum cylindrical pot. -“M-2000” manufactured by B Machine Co., Ltd.), adjusting the heater output so that the temperature immediately after the heating of the surface of the plug portion of the preform charged at room temperature is 183 ± 2 ° C., and the production rate is 1800 The mouthpiece was crystallized as a book / hour. The density of the crystallization plug obtained at this time was measured at 23 ° C. using a sample obtained by cutting the plug into a square of about 5 mm and a density gradient tube made of sodium bromide in water / ethanol. As a result, the density of the top surface of the plug portion was 1.385 g / cm 3 , and the density of the support ring portion of the plug portion was 1.360 g / cm 3 .
次いで、得られた口栓部を結晶化させたプリフォームを、容量1000mlの耐圧容器に収容し、雰囲気温度を30℃とし、25MPaに加圧した二酸化炭素を耐圧容器内に注入し、この温度、圧力下で2時間保持してプリフォームと加圧二酸化炭素を接触させた。その後、25℃で加圧二酸化炭素を5分かけて常圧に戻し、二酸化炭素を溶解させたプリフォームを得た。 Next, the preform obtained by crystallizing the obtained plug part is accommodated in a pressure-resistant container having a capacity of 1000 ml, the atmospheric temperature is set to 30 ° C., and carbon dioxide pressurized to 25 MPa is injected into the pressure-resistant container. The preform and pressurized carbon dioxide were brought into contact with each other while being kept under pressure for 2 hours. Thereafter, pressurized carbon dioxide was returned to normal pressure at 25 ° C. over 5 minutes to obtain a preform in which carbon dioxide was dissolved.
次いで、このプリフォームを用いて成形を行った。成形機には、プリフォーム投入部及びボトル取り出し部、近赤外線ヒーターを備えた1次加熱部、および2次加熱部、ブロー成形部、の順に90度ずつプリフォームが移動し延伸ブローボトルを成形する、回転式延伸ブロー成形機(湖北精工株式会社製)を用いた。プリフォームの1次加熱時間を46秒、2次加熱時間を23秒、2次加熱部における2次加熱終了後の放冷時間を23秒の設定とした。これにより、1次加熱部および2次加熱部のプリフォーム表面温度はそれぞれ90〜100℃、110〜120℃となり、放冷によって、プリフォーム表面温度が100℃〜110℃となる。ここで、3MPaの加圧空気を注入して、長さ約200mm、外径約60mm、平均肉厚約1mm、内容量500mlで、胴部の内外の表面層と胴部の肉厚中央部分が非発泡層であり、該表面層と中央部分に挟まれた部分が発泡層で構成された、多層構造を有するポリエステル樹脂製中空成形容器を得た。 Next, molding was performed using this preform. In the molding machine, the preform moves 90 degrees each in the order of the preform charging unit and bottle take-out unit, the primary heating unit equipped with a near infrared heater, the secondary heating unit, and the blow molding unit to form a stretch blow bottle. A rotary stretch blow molding machine (manufactured by Hubei Seiko Co., Ltd.) was used. The primary heating time of the preform was set to 46 seconds, the secondary heating time was set to 23 seconds, and the cooling time after the completion of the secondary heating in the secondary heating unit was set to 23 seconds. Thereby, the preform surface temperature of a primary heating part and a secondary heating part will be 90-100 degreeC, 110-120 degreeC, respectively, and preform surface temperature will be 100 degreeC-110 degreeC by standing_to_cool. Here, pressurized air of 3 MPa is injected, the length is about 200 mm, the outer diameter is about 60 mm, the average thickness is about 1 mm, the inner volume is 500 ml, and the inner and outer surface layers of the barrel and the thickness central portion of the barrel are A polyester resin hollow molded container having a multi-layer structure, which was a non-foamed layer and the portion sandwiched between the surface layer and the central portion was composed of a foamed layer, was obtained.
得られたポリエステル樹脂製中空成形容器の口栓部では、天面部、サポートリング部とも発泡は見られず(発泡倍率1)、極めて良好な外観であった。また、胴部は、厚さ方向の70%が非発泡層、残部は発泡層であり、その発泡倍率は「発泡層と非発泡層の合計」で1.1倍であったので、発泡層の発泡倍率は1.4倍と計算された。 In the mouthpiece part of the obtained polyester resin hollow molded container, foaming was not seen in the top surface part and the support ring part (foaming ratio 1), and the appearance was very good. Moreover, 70% of the trunk portion in the thickness direction is a non-foamed layer, and the remaining portion is a foamed layer, and the foaming ratio was 1.1 times as "total of foamed layer and non-foamed layer". The foaming ratio was calculated to be 1.4 times.
得られた容器を、柴崎製作所製キャッピング機501型にマグナトルクヘッドVK560を装着し、柴崎製作所製PETボトル用キャップBBW−E8−612を用いて、キャッピングをしたところ正常に嵌合し、良好な密封性が得られた。 When the obtained container was capped with a cap BBW-E8-612 made by Shibazaki Seisakusho Capping Machine 501 with Magna Torque Head VK560 and made by Shibazaki Seisakusho Co., Ltd. Sealability was obtained.
(比較例1)
実施例1において、口栓部の結晶化工程を省略したこと以外は実施例1と同様の方法でポリエステル樹脂製中空成形容器を得、同様にキャッピングを試みた。
(Comparative Example 1)
In Example 1, a polyester resin hollow molded container was obtained in the same manner as in Example 1 except that the plug crystallization step was omitted, and capping was attempted in the same manner.
この比較例1において、ガスの溶解工程に供したプリフォームの口栓部の密度は1.336g/cm3であり、得られた樹脂製中空成形容器の口栓部には発泡があり(発泡倍率1.1倍)、キャップを正常に嵌合できなかった。 In Comparative Example 1, the density of the plug portion of the preform subjected to the gas dissolving step was 1.336 g / cm 3 , and the plug portion of the obtained resin hollow molded container had foaming (foaming) The magnification was 1.1 times), and the cap could not be properly fitted.
本発明により提供される樹脂製中空成形容器は軽量で断熱性や遮光性にも優れ、飲料用容器、食品用容器、化粧品用容器、洗剤、その他医薬品用容器など、多種多様な用途に使用できる。 The resin hollow molded container provided by the present invention is lightweight and excellent in heat insulation and light shielding properties, and can be used for a wide variety of applications such as beverage containers, food containers, cosmetic containers, detergents, and other pharmaceutical containers. .
Claims (3)
該プリフォームを原料樹脂の軟化点以下の温度で超臨界状態にある加圧ガスと接触させて該プリフォームにガスを溶解させる工程と、
ガスを溶解させたプリフォームを原料樹脂のガラス転移点以下の温度で常圧に戻す工程と、
その後、プリフォームを加熱延伸する工程と
を有する樹脂製中空成形容器の製造方法であって、
前記原料樹脂は実質的に発泡剤を含有せず、かつ前記プリフォームにガスを溶解させる工程に先立って、前記プリフォームの口栓部を加熱結晶化させる工程を有し、結晶化後の口栓部の密度が1.35g/cm 3 以上であることを特徴とする樹脂製中空成形容器の製造方法。 Forming a preform of a resin hollow molding container having a cap portion using a raw material resin containing polyethylene terephthalate ;
Contacting the preform with a pressurized gas in a supercritical state at a temperature below the softening point of the raw resin to dissolve the gas in the preform;
Returning the preform in which the gas is dissolved to a normal pressure at a temperature below the glass transition point of the raw resin,
Thereafter, a method for producing a resin hollow molding container having a step of heating and stretching the preform,
The raw material resin is substantially free of blowing agent and prior to the step of dissolving a gas into said preform, have a step of heating crystallized mouth portion of the preform, the mouth after crystallization method for producing a resin hollow molded containers density of the plug portion, characterized in der Rukoto 1.35 g / cm 3 or more.
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JP4853110B2 (en) * | 2006-05-30 | 2012-01-11 | 東洋製罐株式会社 | Manufacturing method of resin integrated molded body |
JP5414162B2 (en) * | 2006-09-12 | 2014-02-12 | 東洋製罐株式会社 | Light-shielding plastic container |
JP5725124B2 (en) * | 2006-09-12 | 2015-05-27 | 東洋製罐株式会社 | Manufacturing method of light-shielding plastic container |
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JP5024166B2 (en) * | 2008-04-04 | 2012-09-12 | 東洋製罐株式会社 | Foamed plastic molding and method for producing the same |
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JP5286561B2 (en) * | 2009-04-08 | 2013-09-11 | 東洋製罐株式会社 | Polyester expanded foam container |
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