JP4315700B2

JP4315700B2 - Heat-resistant bottle made of polyethylene terephthalate resin

Info

Publication number: JP4315700B2
Application number: JP2003046980A
Authority: JP
Inventors: 康文桜井; 克正冨澤; 浩司小野; 徳晃久保; 洋小松原
Original assignee: HOKKAICAN CO.,LTD.
Current assignee: HOKKAICAN CO.,LTD.
Priority date: 2003-02-25
Filing date: 2003-02-25
Publication date: 2009-08-19
Anticipated expiration: 2023-02-25
Also published as: JP2004256128A

Description

【０００１】
【発明の属する技術分野】
本発明は、ポリエチレンテレフタレート樹脂からなる耐熱ボトルに関するものである。
【０００２】
【従来の技術】
近年、内容積１０００ｍｌ以下、例えば３００ｍｌ程度のポリエチレンテレフタレート樹脂（以下、ペット樹脂と略記することがある）製小型ボトルに茶、コーヒー、ミルクコーヒー等の飲料を充填したものを、加温して販売することが行われている。前記ペット樹脂製ボトルは、前記飲料を常温でアセプティック充填した後、内容液が５０〜６０℃程度になるようにホットウォーマー等で加温された状態で保持される。
【０００３】
前記ペット樹脂製ボトルは、一般に、プリフォームを金型内でブロー成形して二軸延伸することにより形成されており、底部内周側にボトル内方向に膨出する凹部を備えることにより、自立性が付与されている。ところが、前記ペット樹脂製ボトルの底部は、前記ブロー成形において十分に延伸されていないため、前記のように加温された状態が長時間続くと、内容物の熱、圧力に耐えきれず、変形が生じる。
【０００４】
この結果、前記ペット樹脂製ボトルでは、容器外観が悪くなったり、容器サイズが変化して、ホットベンダー等に収納した場合には容器が出にくくなることがある。また、ボトル内方向に膨出している前記凹部がボトル外方向に膨出し、甚だしい場合には、該ボトルの自立性が損なわれることがある。
【０００５】
そこで、前記ペット樹脂製ボトルの底部に耐熱変形性を付与する技術が各種提案されている。前記技術の一例として、図７に示すように、底部２１に、環状の接地部２２と、接地部２２の内周側でボトル内部に凸状に膨出する凹部２３と、凹部２３の中央部に形成された平坦面２４から接地部２２に向けて放射状に複数形成されてボトル外方に突出する中空の縦リブ２５とを備えるペット樹脂製ボトル２６が知られている。ペット樹脂製ボトル２６では、縦リブ２５は、凹部２３中央部の平坦面２４に連なる第１の斜面２７と、第１の斜面の端部から接地部に連なる第２の斜面２８とを備え、第１の斜面２７が水平面に対してなす角θは４０〜９０°の範囲で設定される（特許文献１参照）。
【０００６】
図７示のペット樹脂製ボトル２６では、縦リブ２５を前述の形状とすることにより、斜面２７，２８と、縦リブ２５の底面２９との距離Ｈを大きくとることができる。従って、前記ブロー成形の際に、凹部２３のブロー成形量を十分に大きなものとすることができ、茶、コーヒー、ミルクコーヒー等の飲料を充填した際に、凹部２３の変形を防止するために十分な耐熱変形性と強度とを付与できるとされている。
【０００７】
しかしながら、本発明者らの検討によれば、図７示のペット樹脂製ボトル２６は、前記茶、コーヒー、ミルクコーヒー等の飲料を常温でアセプティック充填した後、内容液が５０〜６０℃程度になるようにホットウォーマー等で加熱し長時間保存すると、凹部２３の変形が避けられないとの不都合がある。
【０００８】
【特許文献１】
特開２００２−３０８２４５号公報
【０００９】
【発明が解決しようとする課題】
本発明は、かかる不都合を解消して、茶、コーヒー、ミルクコーヒー等の飲料を高温で充填した後、さらにホットウォーマー等で長時間加温しても、底部が変形することなく、自立性を保持することができるポリエチレンテレフタレート樹脂製耐熱ボトルを提供することを目的とする。
【００１０】
【課題を解決するための手段】
かかる目的を達成するために、本発明のポリエチレンテレフタレート樹脂製耐熱ボトルは、口部と、該口部に連なる肩部と、該肩部に連なる胴部と、該胴部に連なる底部とを備えるポリエチレンテレフタレート樹脂製耐熱ボトルにおいて、
該底部は、該胴部の最大径の７０〜８６％の範囲の外径を備える環状の接地部と、該胴部の最大径の７０〜８０％の範囲の外径を備え、該接地部の内周側で該接地部が形成する平面に対して３５〜６０°の角度をなしてボトル内部に円錐状に立上る立上り部と、該胴部の最大径の６０〜７５％の範囲の外径を備え該立上り部の上端縁に連なりボトル内部に凸状に膨出する凹部と、該凹部の中央部に形成された平坦面と、該平坦面から該立上り部に向けて放射状に複数形成されてボトル外方に突出する中空の縦リブと、該縦リブの間に形成されボトル内部に向けて膨出する谷部とを備え、該縦リブは、該凹部中央部の平坦面に上端部が連なりボトル内方向に凸の曲線状である稜線部と、該稜線部の下端部から該立上り部に向かって次第に拡大され、該立上り部の上端縁が形成する平面に対して２０〜３５°の角度をなして該立上り部の上端縁に連なり、該稜線部の下端部に頂部を形成する斜面とを備え、該谷部の底面は、該凹部中央部の平坦面から該立上り部の上端縁に連なり、ボトル内方向に凸であって、該平坦面の外周近傍では該平坦面よりもボトル内方向に凹入する曲面であることを特徴とする。
【００１１】
本発明のペット樹脂製耐熱ボトルでは、前記接地部が前記胴部の最大径の７０〜８６％の範囲の外径を備えることにより、前記底部が熱により変形することを防止することができる。前記接地部の外径は前記胴部の最大径の７０％未満では該接地部より外側の底部が熱により変形しやすく、またボトルの直立安定性が悪くなる。また、前記接地部の外径が前記胴部の最大径の８６％を超えると、前記底部の該接地部の内側が熱により変形し易くなる。
【００１２】
また、本発明のペット樹脂製耐熱ボトルでは、前記接地部の内周側に設けられた前記立上り部が前記胴部の最大径の７０〜８０％の範囲の外径を備えることにより、該接地部が熱により変形することを防止することができる。前記立上り部の外径が前記胴部の最大径の７０％未満であるときには該接地部の外周側が熱により変形し易くなり、８０％を超えると該立上り部の内周側が熱により変形し易くなる。
【００１３】
前記立上り部は、前記接地部が形成する平面に対して３５〜６０°の角度をなしていることにより、該立上り部の内周側に形成される凹部の中央部を該接地部が形成する平面に対してより高く位置させることができる。前記接地部が形成する平面に対する角度が３５°未満では、前記凹部の中央部を十分に高く位置させることができず、６０°を超えると該凹部の外径が過大になり、該凹部が熱により変形して膨出し易くなる。
【００１４】
また、本発明のペット樹脂製耐熱ボトルでは、前記立上り部の内周側に設けられた凹部が前記胴部の最大径の６０〜７５％の範囲の外径を備えることにより、該凹部が熱により変形することを防止することができる。前記凹部の外径は前記胴部の最大径の６０％未満では、該外径の外周部が熱により変形して膨出し易くなる。また、前記凹部の外径が前記胴部の最大径の７５％を超えると、該外径の内周部の該凹部が熱により変形して外側に膨出し易くなる。
【００１５】
また、本発明のペット樹脂製耐熱ボトルでは、前記縦リブと、該縦リブの間に形成される谷部とにより、前記平坦面から前記接地部に向けて放射状の凹凸が形成され、該凹凸により前記凹部が熱により変形することを防止することができる。ここで、前記縦リブは、前記耐熱性を得るために、ボトル内方向に凸の曲線状の稜線部と、該稜線部の下端部から前記立上り部に向かって次第に拡大されて該立上り部の上端縁に連なり、該稜線部の下端部に頂部を形成する斜面とを備え、該斜面が該立上り部の上端縁の形成する平面に対して２０〜３５°の角度をなしている。前記斜面が前記立上り部の上端縁の形成する平面に対してなす角度が２０°未満であるときには前記凹部が熱により変形して外側に膨出し易くなり、３５°を超えると前記稜線部をボトル内方向に凸の曲線状とすることが難しくなり、耐熱変形性や耐圧強度が低下する。
【００１６】
また、前記谷部は、前記耐熱性を得るために、底面が前記凹部中央部の平坦面から前記立上り部の上端縁に連なり、ボトル内方向に凸の曲面を形成しており、さらに該谷部が前記平坦面の外周近傍で該平坦面よりもボトル内方向に凹入している。前記谷部が前記平坦面の外周近傍で該平坦面よりもボトル内方向に凹入する部分を備えていない場合には、前記凹部が熱により変形しやすくなる。
【００１７】
本発明のペット樹脂製耐熱ボトルによれば、前記形状を全て備えることにより前記底部に優れた耐熱性を付与することができ、茶、コーヒー、ミルクコーヒー等の飲料を高温で充填した後、さらにホットウォーマー等で長時間加温しても、該底部の変形を防止して、自立性を保持することができる。
【００１８】
【発明の実施の形態】
次に、添付の図面を参照しながら本発明の実施の形態についてさらに詳しく説明する。図１は本実施形態のポリエチレンテレフタレート樹脂製耐熱ボトルの概略を示す正面図、図２は図１に示す耐熱ボトルの底部を示す平面図、図３は図２のＩＩＩ−ＩＩＩ線断面図、図４はＩＶ−ＩＶ線断面図である。また、図５、図６は、図１に示す耐熱ボトルの底部の変形量を経時的に示すグラフである。
【００１９】
本実施形態のポリエチレンテレフタレート樹脂製耐熱ボトル１は、プリフォームを金型内でブロー成形して二軸延伸することにより形成された内容積２８０ｍｌの小型ボトルであり、茶、コーヒー、ミルクコーヒー等の加温して販売される飲料の容器に用いられる。図１に示すように、本実施形態のペット樹脂製耐熱ボトル１は、外周面にねじ部を備えた口部２と、口部２に連なる肩部３と、肩部３に連なる略円筒状の胴部４と、胴部４に連なる底部５とを備えている。胴部４は最大径Ｒ₁が５０〜７０ｍｍの範囲にあり、表面には図示しない環状溝部、パネル部等が形成されていてもよい。
【００２０】
底部５は、環状の接地部６と、接地部６の内周側でペット樹脂製耐熱ボトル１内部に円錐状に立上る立上り部７と、立上り部７の内周側でペット樹脂製耐熱ボトル１内部に凸状に膨出する凹部８とを備えている。図２に示すように、凹部８は中央部に平坦面９が形成されている。また、凹部８は、平坦面９から立上り部７に向けて放射状に形成されてペット樹脂製耐熱ボトル１外方に突出する８本の中空の縦リブ１０を備え、縦リブ１０，１０の間には、縦リブ１０と同数の谷部１１が形成されている。縦リブ１０は、稜線部１２と、稜線部１２の端部から立上り部７に向かって次第に拡大されて立上り部７の上端縁に連なる斜面１３とを備えている。
【００２１】
図３に示すように、接地部６は、外周側ではペット樹脂製耐熱ボトル１の外方に向けて凸の曲面１４を介して胴部４に接続されており、内周側では立上り部７を介して凹部８に接続されている。接地部６の外径Ｒ₂は、胴部４の最大径Ｒ₁の７０〜８６％の範囲となるように設定されており、接地部６の幅ｗは０〜３ｍｍの範囲となるように設定されている。
【００２２】
また、立上り部７の外径Ｒ₃は胴部４の最大径Ｒ₂の７０〜８０％の範囲となるように設定されており、立上り部７は、接地部６が形成する平面に対する角度θ₁が３５〜６０°の範囲に設定されてされている。そして、凹部８の外径Ｒ₄は、胴部４の最大径Ｒ₂の６０〜７５％の範囲となるように設定されている。
【００２３】
また、縦リブ１０の稜線部１２は平坦面９に連なりペット樹脂製耐熱ボトル１の内方向に凸の曲線状であり、斜面１３は立上り部７の上端縁が形成する平面に対する角度θ₂が２０〜３５°の範囲に設定されており、稜線部１２の下端部に頂部１５を形成している。尚、平坦面８は稜線部１２と接続する部分の直径Ｒ₅が７〜１０mmの範囲となるように設定されている。
【００２４】
一方、谷部１１は、図４に示すように、平坦面９から接地部６に連なり、ボトル内方向に凸の曲面を形成している。そして、谷部１０は、平坦面９の外周近傍で平坦面９よりもペット樹脂製耐熱ボトル１の内方向に凹入する凹入部１６を備えている。尚、谷部１１は、縦リブ１０の稜線部１２が平坦面９に接続する位置よりも外周側で平坦面９に接続されており、平坦面９は谷部１１と接続する部分の直径Ｒ₄が１１〜１４ｍｍの範囲となるように設定されている。
【００２５】
凹部８が前記形状を備える結果、平坦面９は接地部６が形成する平面からの高さｈが１０〜１５ｍｍの範囲に設定されている。
【００２６】
次に、内容積が２８０ｍｌであり、胴部４の最大径Ｒ₁＝６６ｍｍ、接地部６の外径Ｒ₂＝５１ｍｍ、接地部６の内径Ｒ₃＝５０ｍｍ、立上り部７の接地部６が形成する平面に対する角度θ₁＝４５°、凹部８の外径Ｒ₄＝４２ｍｍ、斜面１３の立上り部７の上端縁が形成する平面に対する角度θ₂＝２５°であり、接地部６が形成する平面に対する平坦面９の高さｈ＝１２ｍｍのペット樹脂製耐熱ボトル１を用意した。このペット樹脂製耐熱ボトル１に、内容物（茶飲料）を充填した後、プレート温度を９０℃に設定したホットプレート上に載置して加温し、接地部６が形成する平面に対する平坦面９の高さｈの経時変化を測定した。結果を図５，６に示す。
【００２７】
図５から、本実施形態のペット樹脂製耐熱ボトル１は加温開始時に１２ｍｍであった平坦面９の高さｈが１２時間後に８ｍｍ強に低下するものの、その後は８ｍｍ強の高さを維持していることが明らかである。また、図６から、本実施形態のペット樹脂製耐熱ボトル１は、さらに７日間が経過しても、平坦面９の高さｈが前記８ｍｍ強の高さを維持しており、底部５が優れた耐熱性を備えていることが明らかである。
【００２８】
尚、本実施形態では、胴部４が略円筒状のペット樹脂製耐熱ボトル１について説明しているが、胴部４が四角柱状であってもよい。また、本実施形態では、ペット樹脂製耐熱ボトル１の内容積を２８０ｍｌとしているが、内容積は特に限定されるものではない。
【図面の簡単な説明】
【図１】本発明に係るポリエチレンテレフタレート樹脂製耐熱ボトルの概略を示す正面図。
【図２】図１に示すペット樹脂製耐熱ボトルの底部を示す平面図。
【図３】図２のＩＩＩ−ＩＩＩ線断面図。
【図４】図２のＩＶ−ＩＶ線断面図。
【図５】図１に示す耐熱ボトルの底部の変形量を経時的に示すグラフ。
【図６】図１に示す耐熱ボトルの底部の変形量を経時的に示すグラフ。
【図７】従来のペット樹脂製ボトルの底部の一構成例を示す説明的断面図。
【符号の説明】
１…ポリエチレンテレフタレート樹脂製耐熱ボトル、５…底部、６…接地部、７…立上り部、８…凹部、９…平坦面、１０…中空の縦リブ、１１…谷部、１２…稜線部、１３…斜面。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat-resistant bottle made of polyethylene terephthalate resin.
[0002]
[Prior art]
In recent years, small bottles made of polyethylene terephthalate resin (hereinafter sometimes abbreviated as PET resin) with an internal volume of 1000 ml or less, for example about 300 ml, are filled with beverages such as tea, coffee, milk coffee, etc. To be done. The PET resin bottle is held in a state heated by a hot warmer or the like so that the liquid content is about 50 to 60 ° C. after the beverage is aseptically filled at room temperature.
[0003]
The PET resin bottle is generally formed by blow-molding a preform in a mold and biaxially stretching, and is provided with a recess that bulges in the bottle inward on the inner peripheral side of the bottom. Sex has been granted. However, since the bottom of the PET resin bottle is not sufficiently stretched in the blow molding, if the heated state continues as described above, it cannot withstand the heat and pressure of the contents and deforms. Occurs.
[0004]
As a result, in the bottle made of the PET resin, the container appearance may be deteriorated or the container size may change, and the container may be difficult to come out when stored in a hot bender. Moreover, when the said recessed part bulging in the bottle inner direction bulges in the bottle outer direction and is serious, the self-supporting property of this bottle may be impaired.
[0005]
Thus, various techniques for imparting heat-resistant deformation to the bottom of the PET resin bottle have been proposed. As an example of the technique, as shown in FIG. 7, an annular grounding portion 22, a concave portion 23 that protrudes into the bottle on the inner peripheral side of the grounding portion 22, and a central portion of the concave portion 23, as shown in FIG. There is known a PET resin bottle 26 including a plurality of radial ribs 25 that are formed radially from the flat surface 24 to the grounding portion 22 and projecting outward from the bottle. In the PET resin bottle 26, the vertical rib 25 includes a first inclined surface 27 that is continuous with the flat surface 24 at the center of the recess 23, and a second inclined surface 28 that is continuous from the end of the first inclined surface to the grounding portion. The angle θ formed by the first inclined surface 27 with respect to the horizontal plane is set in the range of 40 to 90 ° (see Patent Document 1).
[0006]
In the PET resin bottle 26 shown in FIG. 7, the distance H between the inclined surfaces 27 and 28 and the bottom surface 29 of the vertical rib 25 can be increased by forming the vertical rib 25 in the shape described above. Therefore, the blow molding amount of the recess 23 can be made sufficiently large during the blow molding, and in order to prevent the recess 23 from being deformed when filled with beverages such as tea, coffee and milk coffee. It is said that sufficient heat distortion resistance and strength can be imparted.
[0007]
However, according to the study by the present inventors, the PET resin bottle 26 shown in FIG. 7 is filled with the beverage such as tea, coffee, milk coffee and the like at room temperature, and then the content liquid is about 50-60 ° C. Thus, when heated with a hot warmer or the like and stored for a long time, there is an inconvenience that deformation of the recess 23 is inevitable.
[0008]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-308245
[Problems to be solved by the invention]
The present invention eliminates such inconvenience, and after filling beverages such as tea, coffee, milk coffee etc. at high temperature, even if it is heated for a long time with a hot warmer or the like, the bottom does not deform, and it is self-supporting. It aims at providing the heat-resistant bottle made from a polyethylene terephthalate resin which can be hold | maintained.
[0010]
[Means for Solving the Problems]
In order to achieve such an object, a heat-resistant bottle made of polyethylene terephthalate resin of the present invention includes a mouth, a shoulder connected to the mouth, a trunk connected to the shoulder, and a bottom connected to the shoulder. In heat resistant bottles made of polyethylene terephthalate resin,
The bottom portion includes an annular grounding portion having an outer diameter in the range of 70 to 86% of the maximum diameter of the trunk portion, and an outer diameter in the range of 70 to 80% of the maximum diameter of the trunk portion, the grounding portion A rising portion that rises in a conical shape inside the bottle at an angle of 35 to 60 ° with respect to a plane formed by the grounding portion on the inner peripheral side of the inner periphery, and a range of 60 to 75% of the maximum diameter of the barrel portion A concave portion that has an outer diameter and continues to the upper end edge of the rising portion and protrudes in a convex shape inside the bottle, a flat surface formed in the central portion of the concave portion, and a plurality of radial shapes from the flat surface toward the rising portion A hollow vertical rib that is formed and protrudes outward from the bottle, and a trough that is formed between the vertical ribs and bulges toward the inside of the bottle, and the vertical rib is formed on the flat surface of the central portion of the recess. A ridge line part having a curved shape protruding inward from the bottle with the upper end part connected, and gradually expanding from the lower end part of the ridge line part toward the rising part. An inclined surface forming an apex at the lower end portion of the ridge line portion and forming an apex at the lower end portion of the ridge line portion at an angle of 20 to 35 ° with respect to a plane formed by the upper end edge of the rising portion. The bottom surface of the portion extends from the flat surface at the center of the concave portion to the upper edge of the rising portion, and protrudes inward in the bottle, and is recessed in the bottle inward from the flat surface near the outer periphery of the flat surface. It is a curved surface.
[0011]
In the heat-resisting bottle made of PET resin according to the present invention, the bottom portion can be prevented from being deformed by heat because the grounding portion has an outer diameter in the range of 70 to 86% of the maximum diameter of the trunk portion. If the outer diameter of the grounding part is less than 70% of the maximum diameter of the body part, the bottom part outside the grounding part is easily deformed by heat, and the upright stability of the bottle is deteriorated. Further, when the outer diameter of the grounding part exceeds 86% of the maximum diameter of the body part, the inside of the grounding part of the bottom part is easily deformed by heat.
[0012]
In the heat-resistant bottle made of PET resin according to the present invention, the rising portion provided on the inner peripheral side of the grounding portion has an outer diameter in a range of 70 to 80% of the maximum diameter of the trunk portion, whereby the grounding is performed. It is possible to prevent the portion from being deformed by heat. When the outer diameter of the rising portion is less than 70% of the maximum diameter of the body portion, the outer peripheral side of the grounding portion is easily deformed by heat, and when it exceeds 80%, the inner peripheral side of the rising portion is easily deformed by heat. Become.
[0013]
The rising portion forms an angle of 35 to 60 ° with respect to a plane formed by the grounding portion, so that the grounding portion forms a central portion of a recess formed on the inner peripheral side of the rising portion. It can be positioned higher with respect to the plane. If the angle with respect to the plane formed by the grounding portion is less than 35 °, the central portion of the recess cannot be positioned sufficiently high, and if it exceeds 60 °, the outer diameter of the recess becomes excessive, and the recess is heated. This makes it easier to deform and bulge.
[0014]
In the heat resistant bottle made of PET resin according to the present invention, the concave portion provided on the inner peripheral side of the rising portion has an outer diameter in the range of 60 to 75% of the maximum diameter of the trunk portion, so that the concave portion is heated. Therefore, deformation can be prevented. When the outer diameter of the concave portion is less than 60% of the maximum diameter of the body portion, the outer peripheral portion of the outer diameter is easily deformed by heat and bulges easily. Further, when the outer diameter of the concave portion exceeds 75% of the maximum diameter of the body portion, the concave portion of the inner peripheral portion of the outer diameter is easily deformed by heat and easily bulges outward.
[0015]
Further, in the PET resin heat-resistant bottle of the present invention, radial unevenness is formed from the flat surface toward the grounding portion by the vertical ribs and the valleys formed between the vertical ribs. Thus, the concave portion can be prevented from being deformed by heat. Here, in order to obtain the heat resistance, the vertical rib is gradually enlarged from the lower end portion of the ridge line portion toward the rising portion so as to protrude from the lower end portion of the ridge line portion in order to obtain the heat resistance. And a slope that forms a top at the lower end of the ridge line portion, and the slope forms an angle of 20 to 35 ° with respect to the plane formed by the upper edge of the rising portion. When the angle formed by the slope with respect to the plane formed by the upper edge of the rising portion is less than 20 °, the concave portion is easily deformed by heat and bulges outward. It becomes difficult to obtain a curved shape that is convex inward, and heat resistance deformability and pressure strength are reduced.
[0016]
In addition, in order to obtain the heat resistance, the valley portion has a bottom surface that extends from the flat surface of the central portion of the concave portion to the upper edge of the rising portion, and forms a curved surface that protrudes inward of the bottle. The portion is recessed near the outer periphery of the flat surface toward the inside of the bottle than the flat surface. When the trough is not provided with a portion that is recessed in the bottle inward direction from the flat surface in the vicinity of the outer periphery of the flat surface, the concave portion is easily deformed by heat.
[0017]
According to the heat-resistant bottle made of PET resin of the present invention, it is possible to impart excellent heat resistance to the bottom by providing all the shapes, and after filling beverages such as tea, coffee and milk coffee at high temperature, Even if it is heated for a long time with a hot warmer or the like, it is possible to prevent the bottom from being deformed and maintain its independence.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. 1 is a front view schematically showing a heat-resistant bottle made of polyethylene terephthalate resin of the present embodiment, FIG. 2 is a plan view showing the bottom of the heat-resistant bottle shown in FIG. 1, and FIG. 3 is a cross-sectional view taken along line III-III in FIG. 4 is a sectional view taken along line IV-IV. 5 and 6 are graphs showing the amount of deformation of the bottom of the heat-resistant bottle shown in FIG. 1 over time.
[0019]
The heat-resistant bottle 1 made of polyethylene terephthalate resin of the present embodiment is a small bottle having an internal volume of 280 ml formed by blow-molding a preform in a mold and biaxially stretching, and is made of tea, coffee, milk coffee, etc. Used in beverage containers that are sold after heating. As shown in FIG. 1, the heat resistant bottle 1 made of PET resin according to the present embodiment has a mouth portion 2 having a screw portion on the outer peripheral surface, a shoulder portion 3 connected to the mouth portion 2, and a substantially cylindrical shape connected to the shoulder portion 3. The body part 4 and the bottom part 5 connected to the body part 4 are provided. Barrel 4 is in the range of maximum diameter R ₁ is 50 to 70 mm, an annular groove (not shown) on the surface, the panel portion and the like may be formed.
[0020]
The bottom portion 5 includes an annular grounding portion 6, a rising portion 7 that rises in a conical shape inside the PET resin heat-resistant bottle 1 on the inner peripheral side of the grounding portion 6, and a PET resin heat-resistant bottle on the inner peripheral side of the rising portion 7. 1 is provided with a recess 8 bulging in a convex shape. As shown in FIG. 2, the recess 8 has a flat surface 9 at the center. The concave portion 8 includes eight hollow vertical ribs 10 that are formed radially from the flat surface 9 toward the rising portion 7 and project outward from the heat resistant bottle 1 made of pet resin. The same number of troughs 11 as the vertical ribs 10 are formed. The vertical rib 10 includes a ridge line portion 12 and a slope 13 that is gradually enlarged from the end portion of the ridge line portion 12 toward the rising portion 7 and continues to the upper edge of the rising portion 7.
[0021]
As shown in FIG. 3, the grounding portion 6 is connected to the body portion 4 via a curved surface 14 that protrudes outwardly from the PET resin heat-resistant bottle 1 on the outer peripheral side, and the rising portion 7 on the inner peripheral side. It is connected to the recessed part 8 via. Outer diameter R ₂ of the ground portion 6 is set to be in the range of 70 to 86% of the maximum diameter R ₁ of the body portion 4, the width w of the ground portion 6 to be in the range of 0~3mm Is set.
[0022]
Further, the outer diameter R ₃ of the rising portion 7 is set to be in a range of 70 to 80% of the maximum diameter R ₂ of the trunk portion 4, and the rising portion 7 is an angle θ with respect to the plane formed by the grounding portion 6. ₁ is set in the range of 35 to 60 °. The outer diameter R ₄ of the recess 8 is set to be in the range of 60 to 75% of the maximum diameter R ₂ of the body part 4.
[0023]
Further, the ridge line portion 12 of the vertical rib 10 is connected to the flat surface 9 and has a curved shape convex inwardly of the heat resistant bottle 1 made of pet resin, and the inclined surface 13 has an angle θ ₂ with respect to the plane formed by the upper edge of the rising portion 7. It is set in the range of 20 to 35 °, and the top portion 15 is formed at the lower end portion of the ridge line portion 12. The flat surface 8 is set so that the diameter R _{5 of} the portion connected to the ridge line portion 12 is in the range of ₇ to 10 mm.
[0024]
On the other hand, as shown in FIG. 4, the valley portion 11 continues from the flat surface 9 to the grounding portion 6 and forms a curved surface that is convex in the bottle inward direction. The trough 10 is provided with a recessed portion 16 that is recessed inward of the heat resistant bottle 1 made of PET resin near the outer periphery of the flat surface 9 than the flat surface 9. The valley portion 11 is connected to the flat surface 9 on the outer peripheral side of the position where the ridge line portion 12 of the vertical rib 10 is connected to the flat surface 9, and the flat surface 9 has a diameter R of a portion connected to the valley portion 11. ₄ is set to be in a range of 11 to 14 mm.
[0025]
As a result of the concave portion 8 having the above-described shape, the flat surface 9 is set such that the height h from the plane formed by the ground contact portion 6 is in the range of 10 to 15 mm.
[0026]
Next, the inner volume is 280 ml, the maximum diameter R ₁ = 66 mm of the body part 4, the outer diameter R ₂ = 51 mm of the grounding part 6, the inner diameter R ₃ = 50 mm of the grounding part 6, and the grounding part 6 of the rising part 7 The angle θ ₁ = 45 ° with respect to the plane to be formed, the outer diameter R ₄ of the concave portion 8 = 42 mm, and the angle θ ₂ = 25 ° with respect to the plane formed by the upper edge of the rising portion 7 of the slope 13, which is formed by the grounding portion 6. A heat-resistant bottle 1 made of PET resin having a height h = 12 mm of the flat surface 9 with respect to the flat surface was prepared. After filling the plastic resin heat-resistant bottle 1 with the contents (tea beverage), the plate is placed on a hot plate with a plate temperature set to 90 ° C. and heated to form a flat surface with respect to the plane formed by the grounding portion 6. The change with time in the height h of 9 was measured. The results are shown in FIGS.
[0027]
From FIG. 5, the heat-resistant bottle 1 made of PET resin according to the present embodiment has a height h of the flat surface 9 which was 12 mm at the start of heating is lowered to a little over 8 mm after 12 hours, but thereafter maintains a height of a little over 8 mm. Obviously. Moreover, from FIG. 6, the heat resistant bottle 1 made of PET resin according to the present embodiment maintains the height h of the flat surface 9 above 8 mm even after 7 days have passed, and the bottom 5 It is clear that it has excellent heat resistance.
[0028]
In addition, in this embodiment, although the trunk | drum 4 demonstrated the substantially cylindrical PET resin heat-resistant bottle 1, the trunk | drum 4 may be square pillar shape. Moreover, in this embodiment, although the internal volume of the heat resistant bottle 1 made of PET resin is 280 ml, the internal volume is not particularly limited.
[Brief description of the drawings]
FIG. 1 is a front view schematically showing a heat-resistant bottle made of polyethylene terephthalate resin according to the present invention.
FIG. 2 is a plan view showing the bottom of the heat resistant bottle made of PET resin shown in FIG.
3 is a cross-sectional view taken along line III-III in FIG.
4 is a sectional view taken along line IV-IV in FIG.
5 is a graph showing the amount of deformation at the bottom of the heat-resistant bottle shown in FIG. 1 over time.
6 is a graph showing the amount of deformation of the bottom of the heat-resistant bottle shown in FIG. 1 over time.
FIG. 7 is an explanatory cross-sectional view showing an example of the configuration of the bottom of a conventional PET resin bottle.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Polyethylene terephthalate resin heat-resistant bottle, 5 ... Bottom part, 6 ... Grounding part, 7 ... Rising part, 8 ... Recessed part, 9 ... Flat surface, 10 ... Hollow vertical rib, 11 ... Valley part, 12 ... Ridge part, 13 ... slope.

Claims

In a heat-resistant bottle made of polyethylene terephthalate resin, comprising a mouth, a shoulder continuous with the mouth, a trunk continuous with the shoulder, and a bottom continuous with the trunk,
The bottom portion includes an annular grounding portion having an outer diameter in the range of 70 to 86% of the maximum diameter of the trunk portion, and an outer diameter in the range of 70 to 80% of the maximum diameter of the trunk portion, the grounding portion A rising portion that rises in a conical shape inside the bottle at an angle of 35 to 60 ° with respect to a plane formed by the grounding portion on the inner peripheral side of the inner periphery, and a range of 60 to 75% of the maximum diameter of the barrel portion A concave portion that has an outer diameter and continues to the upper end edge of the rising portion and protrudes in a convex shape inside the bottle, a flat surface formed in the central portion of the concave portion, and a plurality of radial shapes from the flat surface toward the rising portion A hollow vertical rib that is formed and protrudes outward from the bottle, and a trough that is formed between the vertical ribs and bulges toward the inside of the bottle,
The vertical rib has a ridge line portion that is curved in a convex shape inward of the bottle with an upper end connected to a flat surface at the center of the concave portion, and is gradually expanded from the lower end portion of the ridge line portion toward the rising portion. An inclined surface that forms an angle of 20 to 35 ° with respect to the plane formed by the upper end edge of the part, continues to the upper end edge of the rising part, and forms a top part at the lower end part of the ridge line part,
The bottom surface of the valley portion extends from the flat surface at the center of the concave portion to the upper edge of the rising portion, and protrudes inward in the bottle. The vicinity of the outer periphery of the flat surface is recessed in the bottle inward from the flat surface. A heat-resistant bottle made of polyethylene terephthalate resin characterized by a curved surface.