JP4282364B2 - Heat-resistant wide-mouth synthetic resin container, manufacturing method and manufacturing apparatus - Google Patents

Description

【００３３】
次に、得られた各容器のフランジ面のヒートシール性を次のようにして検査した。ヒートシール性蓋材として、ＰＥＴ／ＡＬ／ＡＣ／ＶＣ（ポリエステル系）の多層フイルムを使用した。該蓋材を、表２に示すようにシール温度を１４０℃〜２２０℃の範囲で５段階に変えて、ヒートシールした場合の封緘強度及びピール強度を測定した。ヒートシールは、シール圧０．９８ｋＮ／ｃｕｐ、シール時間１ｓｅｃの条件で行なった。封緘強度は、密封された容器を水中で蓋材に注射針を刺し込んで、外部より容器内を順次加圧していき、密封が破れて水中に泡が発生したときの内圧（ｍｍＨｇ）を封緘強度とした。封緘強度１００ｍｍＨｇ以上を合格とした。この測定において、測定器の性能上最高３００ｍｍＨｇまでしか測定できなかったので、３００ｍｍＨｇ超える場合も全て３００ｍｍＨｇと表示してある。
ピール強度は、ＪＩＳに規定されている測定法によって、容器を固定し、蓋材を挟んだシールチャック治具を４５°に持ち上げて、シールが破壊されるときの張力（Ｎ）によって測定した。ピール強度１０Ｎ以上を合格とした。その結果を表２に示す。その結果、シール温度１４０℃でのシールでは、封緘強度、ピール強度とも不足したが、１６０℃以上のシール温度では、十分なヒートシール性を示した。また、そのときのフランジの変形も認められなかった。
【００３４】
【表２】

【００３５】
また、上記のようにして得られた実施例１〜３の各容器にそれぞれに沸騰した水（１００℃）を満杯に充填し、上記ヒートシール性の実験と同様な条件で１６０℃でヒートシールした容器をそれぞれ１０個づつ得た。それぞれについて、外観を観察したところ、容器の変形は殆ど観察されず、何れも１％未満であり、耐熱性を有することが確認された。そして、これらの各容器を底面を下方に向けて５０ｃｍ及び１００ｃｍの高さから自然落下させた場合の、容器の割れ（漏れ）、損傷（底面ヘコミ）について観察した。その結果、表３に示すように、何れの場合も容器の割れ（漏れ）、損傷（底面ヘコミ）が観察されず、落下強度に優れていることが確認された。
【表３】

【００３６】
【発明の効果】
以上のように本発明によれば、未だ実用化されてないフランジ面がヒートシール性を有する広口耐熱合成樹脂容器を簡単な装置で、しかも金型を替えて２段ブローを行なう必要がなく、短時間に成形して離型でき、成形サイクルが短くて安価に得ることができ、その実用化を図ることができた。そして、本発明で得られる広口耐熱合成樹脂容器は、内容物満杯充填状態で１００℃の加熱で１％未満の変形度を保つ耐熱性を有し、蓋材のヒートシール性に優れ、所望の落下強度を有し、且つ透明な容器であり、寸法精度に優れ、安価に製造することができ、内容物を加熱殺菌でき、且つ使用時外部より加温することが可能である。
【図面の簡単な説明】
【図１】本発明の実施形態に係る広口耐熱合成樹脂容器であり、（ａ）はその正面断面図、（ｂ）はその要部拡大図である。
【図２】本発明の他の実施形態に係る広口耐熱合成樹脂容器であり、（ａ）はその正面断面図、（ｂ）はその底面図である。
【図３】本発明の他の実施形態に係る広口耐熱合成樹脂容器であり、（ａ）はその正面断面図、（ｂ）はその要部拡大図である。
【図４】本発明の他の実施形態に係る広口耐熱合成樹脂容器であり、（ａ）はその正面断面図、（ｂ）はその底面図である。
【図５】本発明のさらに他の実施形態に係る広口耐熱合成樹脂容器の一部破断正面図である。
【図６】（ａ）〜（ｆ）は本発明の実施形態に係る広口耐熱合成樹脂容器の製造工程を示す模式図である。
【図７】本発明の実施形態に係る広口耐熱合成樹脂容器の製造装置の要部断面図である。
【図８】その底型を示す概略断面図であり、（ａ）は成形時の状態、（ｂ）は離型時の状態を示している。
【図９】（ａ）〜（ｃ）はその延伸ロッドの実施形態を容器に挿入した状態で示す正面図である。
【図１０】（ａ）〜（ｅ）は離型工程を示す模式図である。
【符号の説明】
１、６、１２．１７、２３ 広口耐熱合成樹脂容器
２、１４、３１ フランジ ３、１９ 肉厚部
４、８ 底部 ７、１３ 口部
１０ 凸部 １５ 白化部分
１６ 非晶部分 １８、２４、３２ 胴部
２５ 膨出部 ３０ プリフォーム
３５ 下型 ３６ ハロゲンランプ
４０ 上型 ４１ 底型
４２ 上型本体 ４３ フランジ係合部
４４ 断熱材 ４５ 凸部
４６ センターロッド ４７ エアー孔
４８ ブローエアー吹込み口 ４９ 空間部
５０〜５２ 延伸ロッド ５６ センターロッド先端ピース
６０〜６２ 縦方向スリット[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transparent wide-mouthed container having a flange for heat-sealing a lid material in an opening and having heat resistance, and a method and apparatus for manufacturing the same.
[0002]
[Prior art]
In recent years, heat-resistant synthetic resin bottles that can be filled with tea beverages and sold in a heated state have been put into practical use and widely distributed. The heat-resistant synthetic resin bottle is formed by heat-molding by blow molding, a screw cap is wound and sealed at the mouth, hot pack and heat sterilization treatment is possible, and it can be applied from the outside of the container with a vending machine or the like. Can be warm. In this way, containers that can be heated and sterilized such as hot packs, retorts, and paste risers and that can be heated at the time of sale are required to be put into practical use in cup-shaped, tray-shaped or other wide-mouthed synthetic resin containers. However, it has not yet been put into practical use. The reason for this is that in the case of a cup-shaped wide-mouthed container, a flange is usually provided in the opening, and the container is sealed by heat-sealing the lid on the flange. To achieve this, the synthetic resin container is required to have heat resistance and heat sealability with the lid, and the contents can be observed from the outside so that the container is transparent and the manufacturing cost is low. However, practical technology that satisfies all such requirements has not yet been developed.
[0003]
Conventionally, the manufacture of a heat-resistant synthetic resin container with a narrow mouth such as a bottle is performed after heat-treating (whitening treatment) in order to prevent thermal deformation at the time of blow molding of the mouth part of the bottomed preform that has been injection-molded. Biaxial stretching blow is performed in the mold, and then heat treatment is carried out by heating at a temperature higher than a certain glass transition temperature and lower than the melting point, and then cooled until the glass transition temperature is reached or lower. For example, see Patent Document 1). However, in that case, it takes a long time to cool the glass mold to the glass transition temperature or lower in the mold after molding, and the productivity is extremely poor. Therefore, in recent years, the first blow mold having a cavity larger than the molded container by a predetermined amount is subjected to biaxial stretch blow and heat treatment, and the second cavity having the same volume as the actual product without being cooled. Production time (especially cooling time) by transferring to the next blow mold and heat shrinking the first blow molded product by second blowing at the temperature below the glass transition to form the shape. (See, for example, Patent Documents 2 and 3). However, in this case, since it is a two-stage blow using different molds, there is a problem that the equipment is doubled and complicated, and the equipment cost is increased.
[0004]
Thus, the heat-resistant bottle container thus obtained is whitened because the body is transparent by stretch orientation crystallization but the mouth is thermal crystallization. The whitened portion has heat resistance but is very vulnerable to impact, and the drop strength is significantly inferior to other portions. In the case of a narrow-mouthed container such as a bottle, the effect is small because the diameter is small, but in the case of a wide-mouthed container, the whitened mouth is larger in diameter than the body, so for example, a container filled with contents is used. When dropped, there is a high probability that the whitened mouth will be hit, and the impact will be large due to the large diameter, so that the mouth will be broken and the drop strength required for the product cannot be satisfied. This is one of the factors that hinder the practical application of heat-resistant wide-mouth synthetic resin containers. In addition, since the mouth portion that has been whitened and crystallized is extremely inferior in heat sealability, there is a problem that it cannot be applied to a container in which a lid material is heat sealed to the mouth portion and sealed, such as a wide mouth container.
[0005]
In order to solve this problem, as a means for ensuring the heat sealability of the crystallized mouth part, for example, a method in which the crystallized mouth top surface is heated again and rapidly cooled to be amorphous (Patent Document) 4, see Patent Document 5). However, these methods require a special heating / cooling process for the container forming process in addition to the container forming process, and there are problems that the manufacturing process is complicated, the manufacturing efficiency is lowered, and the equipment cost is increased. Is difficult.
[0006]
On the other hand, as a conventional method for producing a synthetic resin wide-mouth container, a flat preform is held by a chucking plate and is molded by pressure forming or vacuum forming (see Patent Documents 6 and 7). The thermoforming method is used (see Patent Document 4). The thus obtained wide-mouth container generally does not have heat resistance, and in order to impart heat resistance, the entire container must be thermally crystallized. There is a problem that it cannot be obtained.
[Patent Document 1]
JP-A-58-18230
[Patent Document 2]
Japanese Patent Laid-Open No. 60-189418
[Patent Document 3]
JP-A-9-314650
[Patent Document 4]
Japanese Patent Publication No. 7-80502
[Patent Document 5]
JP 2000-15691 A
[Patent Document 6]
Japanese Patent Publication No. 3-74169
[Patent Document 7]
JP-A-5-69473
[0007]
[Problems to be solved by the invention]
Conventionally, as a means for imparting heat resistance to a blow molded container such as a bottle or the like, a preform is biaxially stretched during blow molding to increase the degree of orientation, and heat set at a high temperature to increase the crystallinity. The method is generally adopted. However, in the case of a container in which a lid is heat sealed to the flange as described above, when the flange is crystallized, there is a problem that heat sealing performance is remarkably deteriorated and sealing by heat sealing becomes difficult. In addition, in order to impart heat resistance, when the flange is heated and rapidly cooled, there is a problem that the flange is likely to be deformed, resulting in heat seal inhibition, and so on. Not yet commercialized. Further, since the conventional heat-resistant blow molding is performed by two-stage molding, there is a problem that the equipment cost increases and the productivity decreases due to the increase in the number of processes.
[0008]
The present invention was devised in view of the above circumstances, and is transparent and capable of being formed by blow molding in a short time within a single mold without impairing the heat sealability of the flange. An object of the present invention is to provide a heat-resistant synthetic resin wide-mouthed container having heat-sealability, and a method and apparatus for producing the same.
[0009]
[Means for Solving the Problems]
  The heat-resistant wide-mouthed synthetic resin container of the present invention for solving the above problems is a blow-molded wide-mouthed synthetic resin container having a flange at the opening end, and the body part excluding the flange is transparent and heat-resistant by heat treatment after stretching orientation And the flange upper surface has heat sealabilityAnd the container mouth part below the flange is a stretched and oriented thick part, and the bottom part is convex inward, and the synthetic resin container is formed of a thermoplastic polyester resin system, Degree of deformation after full filling of the content is less than 3% heat resistanceIt is characterized by. Here, the flange includes not only a disk-like flat flange but also a case where a reinforcing annular portion having a circular arc shape or the like is included.
[0010]
It is desirable that the container mouth part below the flange is a thick part and the bottom part is convex inward, thereby improving heat resistance and strength. The said thickness part is 2-4 times the thickness of other trunk | drum parts, and it is the range of 2.5 mm or more from an opening edge part, and the container whose content is 350 ml or less depending on the size of the container In this case, it is desirable to form up to 15 mm. Moreover, as a convex shape of a bottom part, a dome shape, a petal shape, etc. are suitable. When the flange is crystallized only on the back side and the front side (seal side) is in an amorphous state or has a low degree of crystallinity and maintains heat sealability, the heat-sealing wide-mouth container with higher heat distortion resistance Can be obtained. The synthetic resin container is not particularly limited in the material of the synthetic resin, but is formed of a thermoplastic polyester resin system, and the degree of deformation after full filling of the contents having a heat resistance of 100 ° C. is less than 2%. desirable.
[0011]
The heat-resistant wide-mouth synthetic resin container manufacturing method of the present invention for manufacturing the above-mentioned heat-resistant wide-mouth synthetic resin container is a temperature range from the glass transition temperature to the melting point and below the preform having a flange at the open end and a closed bottom. In the mold heated at, in the state where heat transfer from the mold to the flange is reduced during blow molding, the process of longitudinal stretching with a stretching rod, transverse stretching, complete shaping and heat setting by air pressure And a cooling step in which high-pressure air is blown onto the inner surface of the container by a stretching rod to cool the glass transition temperature or lower.
[0012]
The process of lateral stretching and complete shaping with the air pressure is a pre-blow process of transverse stretching and orientation with an air pressure of 0.7 to 1.0 MPa, and complete shaping into the product shape with high pressure air of 3.0 to 4.0 MPa. And a high pressure blow process that promotes crystallization by holding it with a high temperature mold. The cooling step can cool the inner peripheral surface of the container to the glass transition temperature or less in a short time due to the heat insulating effect by blowing slit-like high-pressure air in the vertical axis direction from the vertical slit of the stretching rod to the inner peripheral surface of the container body. The cycle can be shortened significantly. By having a preform pretreatment process that heats only the opposite side of the heat-seal surface of the preform flange before blow molding, the back side of the flange is whitened, resulting in a high degree of crystallization. It is possible to obtain a wide-mouthed container having superior heat resistance than the side having an amorphous state or low crystallinity and heat sealability.
[0013]
Moreover, the heat-resistant wide-mouth synthetic resin container manufacturing apparatus of the present invention for blow-molding the heat-resistant wide-mouth synthetic resin container has a flange support surface that supports the flange surface of the preform, and an opening through which a stretching rod passes in the center portion. A lower mold having a lower mold, an upper mold having a blow molding cavity that engages with the flange support surface side of the lower mold, and a stretching rod, and the upper mold includes a flange engaging member that engages with the flange surface of the preform; And an upper mold body member forming a cavity, wherein the flange engaging member is thermally coupled to the upper mold body.
[0014]
By providing a convex bottom mold in the cavity at the bottom of the upper mold, the container bottom can be stretched and oriented during blow molding. The bottom mold is provided with a center rod that can be driven up and down at the center thereof, an air passage is formed in the axial direction of the center rod, and a structure having an air blowing hole at the tip thereof is provided. The mold can be released well without being deformed. The extending rod has an air passage inside in the axial direction, forms a vertical slit leading to the air passage on the outer periphery of the shaft, and allows cooling air to be blown in the axial direction of the inner peripheral surface of the container through the vertical slit. By constituting in this way, it becomes possible to cool the container effectively in a short time after heat setting. Further, the lower mold is configured to be rotatable while supporting the preform, supports and rotates the preform supplied to the lower mold, and heats the outer periphery of the preform by a heating means provided in the external fixing portion. By doing so, only the back surface of the preform can be heat-treated.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, various embodiments of the heat-resistant wide-mouth synthetic resin container obtained in the present invention will be described with reference to FIGS. Each of the heat-resistant wide-mouthed synthetic resin containers of these embodiments shows a cup shape, but the shape is not particularly limited. These containers are manufactured by biaxial stretch blow molding by a method described later. These heat-resistant wide-mouthed synthetic resin containers have heat resistance that maintains a degree of deformation of less than 3%, preferably less than 1% when heated at 100 ° C. when the contents are filled, and the flange of the mouth is heat-sealed. It has a property that it has a drop strength that does not cause damage such as cracking of the flange even if it falls from 50 cm or more, preferably 100 cm when filled with the contents, and is a transparent container. Satisfies. In order to satisfy these conditions, it is desirable that the surface of the flange has a crystallinity of 5% or less and the main body has a crystallinity of 35% or more.
[0016]
The material of the heat-resistant wide-mouth synthetic resin container of the present invention that satisfies the above conditions is not particularly limited as long as it is a resin that is crystallized by stretch orientation and has heat resistance, but a thermoplastic resin having a high stretch orientation effect is desirable, For example, a thermoplastic polyester such as polyethylene terephthalate (PET), a single layer such as polypropylene, or a multilayer composite resin including a layer having gas barrier properties in the middle, or a biodegradable resin can be employed. Also shows a case where PET is employed. In addition, a common shape feature of the heat-resistant wide-mouth synthetic resin container in these embodiments has a thick flange at the mouth, and is thickened by a predetermined height from the flange toward the trunk. And the bottom part is in a convex state inward. In the case of a container whose thickness is 2 to 4 times the thickness of the other body and 2.5 mm or more from the open end, depending on the size of the container, but whose inner volume is 350 ml or less Is preferably formed within a range of 15 mm or less. A manufacturing method in which the container mouth portion has such a shape, and heat transfer from the mold to the flange is prevented at the time of molding as will be described later, and stretch orientation and heat treatment can be performed as close as possible to the flange including the thick portion. By adopting, at least the surface of the flange is in an amorphous state or maintains a low crystallinity of about 5% and has a heat seal property, and the thick part near the flange has a crystallinity by heat setting with stretch orientation Can be increased. This increases the strength of the mouth, and in combination with the heat insulation of the flange during molding, it can prevent thermal deformation during molding even if the flange does not crystallize, and can increase the strength of the flange after molding. it can. Also, by making the bottom part convex inward, the biaxial stretching degree of the bottom part can be increased during blow molding of the container, heat resistance is improved, and deformation of the bottom part due to heating during thermal sterilization of the contents is prevented. can do. In order to enable the stretching orientation at the bottom, it is desirable to have a convex shape of 10 mm or more. Further, by making the bottom part convex inward, the pressure resistance is improved, and it is also possible to fill the internal pressure generating contents such as carbonated drinks.
[0017]
The heat-resistant wide-mouth synthetic resin container 1 according to the embodiment shown in FIG. 1 has a flange 2 at the mouth that is thicker than a biaxially stretched body, and extends from the flange to a predetermined depth at the entrance of the body. It is a thick part 3. On the other hand, the bottom part 4 has a dome shape at the center and a little thickness near the dome top part 5. The thickness of the thick part is desirably about 2 to 4 times the thickness of the other part of the body part, and is about 3 times thicker in this embodiment. Although the thick portion 3 is hardly stretched in the transverse direction even if it is longitudinally stretched during molding, the degree of crystallinity is lower than that of the lower portion of the body portion, but can remain transparent during heat treatment.
[0018]
In the heat-resistant wide-mouth synthetic resin container 6 of the embodiment shown in FIG. 2, the shape of the mouth portion 7 is the same as that of the above-described embodiment, but the shape of the bottom portion 8 is the center except for the flat ring portion 9 near the outer peripheral portion as a whole. The portion is a convex portion 10 inside. And this convex part has the ridgeline 11 extended radially from the center part, and is exhibiting the petal shape. Thereby, the heat resistance strength and pressure resistance strength of the bottom are further improved.
[0019]
The bottom part of the heat-resistant wide-mouthed synthetic resin container 12 of the embodiment shown in FIG. 3 is the same as that of the heat-resistant wide-mouthed synthetic resin container shown in FIG. 2, but the shape of the mouth part 13 is different. In particular, in the present embodiment, as shown in the enlarged view (b) in the figure, the flange 14 is thermally crystallized and whitened by heating on the side opposite to the heat seal surface, and from the whitened portion 15 and the amorphous portion 16. Thus, the heat resistance is further improved. In the whitening treatment, it is possible to whiten only the back surface side by applying a heat plate from the back surface of the flange and performing heat setting at the preform stage. Desirably whitening to a depth of / 5. Thereby, since the surface of a flange can maintain an amorphous state or a low crystalline state, heat sealability can be secured. Further, even if the flange is whitened, the transparency of the container for observing the contents is not affected at all. Furthermore, even if the back surface of the flange is whitened, the amorphous portion remains on the surface, and the upper end of the body portion below the flange is thick, so that a desired drop strength can be obtained.
[0020]
The heat-resistant wide-mouthed synthetic resin container 17 shown in FIGS. 4 and 5 has a mouth and a bottom shape that are substantially the same as those shown in the above embodiment, but the shapes of the body portions 18 and 24 are different. Yes. The body portion 18 of the heat-resistant wide-mouthed synthetic resin container 17 shown in FIG. 4 has a reverse tapered portion 20 in which the portion immediately below the thick portion 19 extends slightly outward, and the lower end of the body portion 18 is reduced in diameter in a step shape. The taper wall has a one-step tapered wall up to a substantially intermediate height, and the lower part is a tapered wall with a diameter reduced stepwise to the bottom. In the heat-resistant wide-mouth synthetic resin container 23 shown in FIG. 5, the lower half of the body wall 24 is formed in a wave shape in which a semicircular arc-shaped bulging portion 25 and a valley 26 are connected to each other. By making the body wall as shown in FIGS. 4 and 5, the panel strength of the body wall is increased, the pressure resistance is improved, and the heat resistance is also improved.
As mentioned above, although various embodiment of the heat resistant wide-mouth synthetic resin container which concerns on this invention was shown, this invention is not limited to these embodiment. Next, an embodiment of the production apparatus of the present invention for producing the heat-resistant wide-mouth synthetic resin container as described above will be described.
[0021]
Conventionally, a specific apparatus for producing a heat-resistant wide-mouth synthetic resin container by blow molding has not been proposed, but the heat-resistant wide-mouth synthetic resin container manufacturing apparatus (hereinafter simply referred to as a manufacturing apparatus) of the present invention is a conventional heat-resistant Compared with a blow molding apparatus for a normal wide-mouth container and a narrow-mouth heat-resistant container, the construction is particularly characterized by the structure near the flange engaging portion of the upper mold, the structure of the bottom mold, and the stretching rod.
The manufacturing apparatus of the present embodiment includes a lower mold 35, an upper mold 40, a bottom mold 41, and a stretching rod 50, as schematically shown in FIG. The upper mold 40 is formed as a split mold and forms a cavity having a final shape volume of a wide-mouth container to be molded, and a bottom mold 41 for molding the container bottom is fitted to the center of the upper surface so as to be movable up and down. The upper die 40 and the bottom die 41 have a built-in heater for heating the die to a desired temperature, and heat setting after blow molding is possible by heating the die to a predetermined temperature during blow molding. . However, as described above, the container of the present invention has a certain section below the flange to be thick, stretch-oriented to the thick portion, and heat set to provide heat resistance, and the crystallinity of the flange can be increased. Without increasing, the heat distortion resistance and drop strength of the flange are increased, and the heat sealability of the flange surface is secured. Therefore, as shown in FIG. 6, a special device is applied to the opening of the upper mold 40 so that the flange is not heated during blow molding. That is, in order to prevent the preform flange 31 from being heated and thermally crystallized during blow molding, the upper mold 40 is formed so that the mold portion in contact with the preform flange is not heated. 42 and a flange engaging portion 43 that presses the flange 31 are configured separately. The flange engaging portion 43 is formed with a cooling water circulation path so that the cooling water can circulate therein, and is cooled from the inside, and a heat insulating material 44 is provided between the upper mold main body 42 and the space portion 49. It is provided for air insulation. As shown in FIG. 6, the mold surface of the flange engaging portion 43 that is in contact with the container body part entrance is formed to be as thin as possible, and the upper mold body 42 hits as far as possible above the thick part 3 of the container mouth. It can be heat set. Thereby, the stretched orientation and heat setting of the thick portion 3 below the flange are enabled, the crystallization of the portion is promoted, and the heat distortion resistance is imparted even without thermal crystallization of the flange.
[0022]
The bottom mold 41 is provided through the bottom of the upper mold 40 so as to be movable up and down, and has a configuration shown in FIG. The bottom mold 41 is a convex portion 45 having a molding surface protruding inward of the container so that the bottom of the container to be molded can be stretched even when pre-blowing. The height of the convex portion is 3 to 15 mm, particularly 10 mm before, in order to increase the stretching orientation degree of the container bottom.rearIs desirable. As the specific shape of the convex portion 45, an arbitrary shape such as a dome shape or a petal shape can be adopted according to the shape of the bottom of the container to be molded. In the embodiment shown in FIG. 8, the bottom mold 41 has a petal-like shape for molding the heat-resistant wide-mouth synthetic resin container shown in FIG. By adopting such a petal shape, the surface area of the bottom portion is increased, the stretch orientation degree is increased and the heat resistance is increased, and the ridge portion functions as a reinforcing rib to improve the strength. A center rod 46 is provided at the center of the bottom mold 41 so as to be vertically movable in order to improve mold releasability at the time of mold release. At the time of mold release, as shown in FIG. 8B, at the moment when the bottom mold 41 rises, the center rod 46 is pushed out to hold the gate portion of the container, and the bottom mold and the container are released. In addition, an air hole 47 is provided at the center of the center rod 46, and air is blown to the bottom of the container at the time of mold release to increase the degree of cooling of the bottom and improve the mold releasability. In the present embodiment, the tip of the center rod 46 has a good heat release property andPeelingIt is composed of a tip piece 48 formed of a material having good properties, thereby realizing good die cutting at the bottom and high speed.
[0023]
The stretching rod is longitudinally stretched by the tip portion of the stretching rod hitting the bottom of the preform. The stretching rod of the present invention has a function of instantaneously cooling the molded product as well as the preform longitudinal stretching function. Various embodiments of the stretching rod are shown in FIGS. 9 (a)-(c). These extending rods 50 to 52 are formed in a spherical shape so that the tip portions 53 to 55 can be easily engaged with the top of the dome-shaped preform, and cooling air passages 56 to 58 are formed in the center in the longitudinal axis direction. Yes. A plurality of longitudinal longitudinal slits 60 to 62 are formed radially so as to be continuous with the cooling air passage within a range located in the stretched rod molded product, and high-pressure cooling air is fed from the narrow vertical slit to the body of the molded product. By blowing on the inner peripheral surface of the part, the inner peripheral surface of the molded product is cooled. The drawing rod 50 in FIG. 6A shows its basic form, and in the drawing rod 51 shown in FIG. 4B, the longitudinal longitudinal slit has a longitudinal longitudinal slit 61 and a trunk portion facing the vicinity of the central portion of the trunk portion. It is formed in two steps of the vertical longitudinal slit 63 facing the vicinity of the thick portion of the opening. Thereby, the heat | fever deformation | transformation of the container opening is blocked | prevented by actively cooling the part with a weak drawing orientation effect. Further, a plurality of extending rods 52 shown in FIG. 6C are connected to the cooling air passage so that high-pressure air is blown out toward the tip 55 near the convex portion of the container bottom, particularly the ridge of the petal-like convex portion. The cooling air ejection hole 65 is formed. Thereby, like the container mouth portion, a portion having a weak stretching orientation effect is intensively cooled to prevent deformation of the portion.
[0024]
FIG. 6 shows a molding process in the embodiment of the heat-resistant wide-mouth synthetic resin container manufacturing method of the present invention using the apparatus as described above. In this embodiment, the case where the heat resistant wide-mouth synthetic resin container 1 shown in FIG. 1 is manufactured by blow molding using PET resin as a raw material is shown.
The manufacturing process of the heat-resistant wide-mouth molded container of the present embodiment includes (1) preform heating process, (2) longitudinal stretching process, (3) pre-blowing process (lateral stretching process), and (4) complete shaping process (high pressure process) (Blow process), (5) cooling blow process, and (6) mold release process. Processes (2) to (5) are performed with the mold completely closed.
Therefore, in this embodiment, although it is a method for producing a wide-mouth container having heat resistance and a flange having heat sealability, a two-stage blow process using two types of processing steps and two types of molds to provide heat sealability to the flange. There is no process, the process is simplified, the molding cycle can be further shortened, and productivity is improved. Hereinafter, it demonstrates in detail in order of each process.
[0025]
(1) Preform heating process
In order to enable good biaxial stretching even if the preform 30 is a wide-mouthed container, as shown in an enlarged view in FIG. The top 33 is formed in a hemispherical shape. The preform is formed by injection molding. As shown in FIG. 6A, the preform 30 is placed on the flange receiving portion 36 of the lower mold 35, and a halogen lamp 32 as a heater is arranged at a predetermined interval on the outer periphery of the preform. 30 is heated. At that time, by rotating the lower mold 35 and rotating the preform 30, the surface of the preform can be heated uniformly in the circumferential direction. In this state, the glass is heated to a glass transition temperature that can be stretched. When the heating of the preform is completed, the lower die 35 revolves and reaches the blow molding position, and the upper die 40 is lowered to form a blow molding die with the lower die 35.
[0026]
(2) Longitudinal stretching process
The upper mold body 42 and the bottom mold 41 are heated to a temperature necessary for heat-fixing the resin after biaxial stretching with a built-in heater above the glass transition temperature and below the melting point, and the heating temperature is (glass transition temperature + 30 ° C. ) To (melting point −20 ° C.), in the case of PET resin, a range of 130 ° C. to 180 ° C. is desirable, and in this embodiment, the resin is heated to 140 ° C. However, the flange engaging portion 43 is thermally insulated from the upper mold body and is suppressed to a glass transition temperature or lower (80 ° C. or lower). When the lower mold 42 on which the preform 30 is placed in this state arrives, the mold is closed, and the upper mold main body 42, the flange engaging portion 43, and the bottom mold 41 form a cavity. From this state, the stretching rod 30 ascends from the opening of the lower mold 35 and extends in the vertical direction until the bottom of the preform 30 hits the central protrusion of the bottom mold 41 as shown in FIG. At that time, the stretching rod is raised at a high speed (for example, 0.20 seconds), whereby the preform can be stretched and oriented more effectively and crystallization can be promoted. The preform is stretched in the longitudinal direction as a whole from the thick portion of the flange root to the bottom, except for the flange 31 pressed by the flange engaging portion 43.
[0027]
(3) Pre-blowing process (transverse stretching process)
Next, as schematically shown in FIG. 6 (c), the preform is supplied by supplying blow air from a blow air blowing port (gap) 48 formed by a gap between the lower mold and the extending rod as indicated by an arrow. Is stretched horizontally and pre-blowed. The air pressure for pre-blowing is transversely oriented in a short time with low-pressure air (normal blow pressure) of 0.7 to 1.0 MPa, and further promotes crystallization. By air blowing, the body part is expanded in the circumferential direction and is horizontally stretched until the entire surface is in contact with the inner surface of the upper mold main body 42. However, the bottom mold 41 is also formed so that the bottom mold 41 protrudes into the bottom shape. It is stretched simultaneously until it touches the surface.
[0028]
(4) Complete shaping process (high pressure blow process)
At the same time that the outer peripheral surface of the molded product comes into contact with the cavity wall surface, the air pressure is switched to high pressure air of 3.0 to 4.0 MPa, and it is brought into close contact with the mold surface with high pressure air for complete shaping and at a high temperature. Heat treatment (heat setting) is performed while maintaining a close contact with the heated mold surface. Residual stress during stretching is removed by heat treatment, and crystallization by heating is promoted. The complete shaping with the high-pressure air and the heat setting time are preferably set to be 2-3 times longer than the pre-blow time. As described above, by switching the blow air pressure in two stages, and particularly performing complete shaping and heat setting with high-pressure air, a stretching effect can be obtained and the crystallinity can be improved. Therefore, there are advantages such that the heat resistance of the container is improved while remaining transparent, and the dimensional accuracy of the container is increased.
During the above blow molding process, the flange engaging portion of the upper mold is insulated from the upper mold main body, so that the temperature rise is small and the deformation of the flange due to heat during molding is prevented.
[0029]
(5) Cooling blow process
The cooling blow process hits the inner peripheral surface of a molded product that has been heat-formed by 3.0-4.0MP high-pressure cooling air that is radially formed from the longitudinal slits 56 that are radially formed in the longitudinal direction of the drawing rod. Quickly cool the inner surface. In the present invention, high-pressure air is blown to the inner peripheral surface of the container from the narrow vertical slits 60 that are radially arranged on the stretching rod, so that the inner surface of the container is adiabatically expanded with a large differential pressure. Since the inner surface of the molded product is cooled by the effect, the cooling effect is higher than in the case of conventional blow molding, the molded product is rapidly cooled, and the molded product can be cooled in a short time. As shown in the drawing, the cooling air hitting the inner peripheral surface of the molded product is discharged to the outside from the air blow inlet 48 on the outer peripheral portion of the stretching rod. In this manner, the molded product is cooled in the mold until the molded product is below the glass transition temperature. In the present invention, as described above, the cooling effect is remarkably high as compared with the conventional case, so that it can be cooled in 1 to 2.5 seconds, and is significantly shorter than the cooling time after the heat treatment of the conventional narrow-mouthed container. Thus, there is no need for two-stage blowing by changing the mold.
[0030]
(6) Mold release process
When the molded product is cooled to the glass transition temperature as described above, the molded product is evacuated and released. Details of the mold release process are shown in FIG. FIG. 10A shows a state where the cooling is completed, and the upper die 40 is opened from this state, and the molded product is sandwiched between the lower die 35 and the bottom die (FIG. 10B). In this state, the center rod 46 of the bottom mold 41 is pressing the bottom of the molded product as shown in FIG. At the moment when the bottom mold 41 rises from this state, the center rod 46 is pushed out, the center part (gate part) of the molded product is pressed, and the bottom mold 41 and the bottom part of the container are released ((c) in the figure). Next, by blowing air from the center rod 46 to the center of the bottom of the molded product, the vicinity of the gate of the molded product is cooled, and thus the mold can be released well without deforming the bottom of the molded product. . After the release, the center rod is raised and ready for the next molding ((e) in the figure). A center rod tip piece 56 formed of a material different from that of the center rod main body is integrally provided at the tip of the center rod 46 as clearly shown in FIG. The center rod tip piece 56 is preferably formed of a resin having low thermal conductivity and excellent releasability, such as polyether ether ketone (PEEK). Thereby, the releasability from the bottom mold is further improved, and the mold can be released at high speed without deforming the bottom.
[0031]
【Example】
Examples 1-3
A heat-resistant wide-mouth synthetic resin container having the shape shown in FIG. 1 (Example 1), FIG. 2 (Example 2), and FIG. 3 (Example 3) was produced under the following conditions. PET was used for the material of the container.
preformsurfaceTemperature: 90-95 ° C
Upper mold heating temperature: 140 ° C. to 165 ° C.
Heating temperature of bottom mold: 130 ° C
Cooling of the flange engaging part of the upper mold: Maintaining the measured temperature of the flange engaging part at 70 ° C. or less by circulating cooling water of 10 ° C. to 20 ° C.
Pre-blow pressure: 1.0 MPa
High pressure blow pressure: 4.0 MPa
Cooling blow pressure: 4.0 MPa
Pre-blow time: 0.7 seconds
High pressure blow time: 2.2 seconds
Cooling blow time: 1.2 seconds
One molding cycle: 8.5 seconds
For Example 2, a 190 ° C. hot plate was applied to the lower surface of the preform, and the lower surface of the flange was heated and whitened with a circular halogen heater from the lower surface of the flange or the lower surface of the preform.
Each container blow-molded in this way was transparent, and there was no thermal deformation such as a flange when taken out from the mold, and all of the containers could be released in a good shape. And the dimension of each obtained container is as Table 1, and the dimension as a design was obtained.
[0032]
[Table 1]

[0033]
Next, the heat sealability of the flange surface of each obtained container was inspected as follows. A PET / AL / AC / VC (polyester) multilayer film was used as the heat-sealable lid. As shown in Table 2, the sealing temperature was changed in five stages within the range of 140 ° C. to 220 ° C., and the sealing strength and peel strength were measured when the lid was heat sealed. The heat sealing was performed under conditions of a sealing pressure of 0.98 kN / cup and a sealing time of 1 sec. Sealing strength is sealed by sealing the sealed container in water with an injection needle inserted into the lid and pressurizing the container sequentially from the outside to seal the internal pressure (mmHg) when the seal is broken and bubbles are generated in the water. Strength. A sealing strength of 100 mmHg or more was considered acceptable. In this measurement, measurement was possible only up to a maximum of 300 mmHg due to the performance of the measuring instrument, and therefore all cases exceeding 300 mmHg are displayed as 300 mmHg.
The peel strength was measured by the tension (N) when the seal was broken by fixing the container and lifting the seal chuck jig sandwiching the lid material to 45 ° by the measurement method prescribed in JIS. A peel strength of 10 N or more was accepted. The results are shown in Table 2. As a result, sealing with a seal temperature of 140 ° C. was insufficient in both sealing strength and peel strength, but sufficient heat-sealability was exhibited at a seal temperature of 160 ° C. or higher. Further, no deformation of the flange was observed at that time.
[0034]
[Table 2]

[0035]
Also, each of the containers of Examples 1 to 3 obtained as described above was fully filled with boiling water (100 ° C.) and heat-sealed at 160 ° C. under the same conditions as in the heat-sealability experiment. Ten containers each were obtained. When the appearance was observed for each, almost no deformation of the container was observed, and all were less than 1%, confirming that they had heat resistance. Then, when these containers were naturally dropped from a height of 50 cm and 100 cm with the bottom face directed downward, the containers were observed for cracks (leakage) and damage (bottom dents). As a result, as shown in Table 3, in any case, no crack (leakage) or damage (bottom dent) of the container was observed, and it was confirmed that the drop strength was excellent.
[Table 3]

[0036]
【The invention's effect】
As described above, according to the present invention, it is not necessary to perform a two-stage blow by changing the mold with a simple device of a wide-mouth heat-resistant synthetic resin container in which the flange surface that has not yet been put into practical use has heat sealability. Molding can be performed in a short time, and the molding cycle is short and can be obtained at a low cost. The wide-mouth heat-resistant synthetic resin container obtained in the present invention has heat resistance that maintains a degree of deformation of less than 1% by heating at 100 ° C. when the contents are filled, and is excellent in the heat sealability of the lid material. It has a drop strength and is a transparent container, has excellent dimensional accuracy, can be manufactured at low cost, the contents can be sterilized by heating, and can be heated from the outside during use.
[Brief description of the drawings]
FIG. 1 is a wide-mouth heat-resistant synthetic resin container according to an embodiment of the present invention, in which (a) is a front sectional view thereof and (b) is an enlarged view of a main part thereof.
FIG. 2 is a wide-mouth heat-resistant synthetic resin container according to another embodiment of the present invention, in which (a) is a front sectional view thereof and (b) is a bottom view thereof.
FIG. 3 is a wide-mouth heat-resistant synthetic resin container according to another embodiment of the present invention, in which (a) is a front sectional view thereof, and (b) is an enlarged view of a main part thereof.
FIG. 4 is a wide-mouth heat-resistant synthetic resin container according to another embodiment of the present invention, in which (a) is a front sectional view thereof and (b) is a bottom view thereof.
FIG. 5 is a partially cutaway front view of a wide-mouth heat-resistant synthetic resin container according to still another embodiment of the present invention.
FIGS. 6A to 6F are schematic views showing a manufacturing process of a wide-mouth heat resistant synthetic resin container according to an embodiment of the present invention.
FIG. 7 is a cross-sectional view of a main part of a wide-mouth heat resistant synthetic resin container manufacturing apparatus according to an embodiment of the present invention.
8A and 8B are schematic cross-sectional views showing the bottom mold, in which FIG. 8A shows a state during molding, and FIG. 8B shows a state during mold release.
FIGS. 9A to 9C are front views showing an embodiment of the extending rod inserted into a container. FIGS.
FIGS. 10A to 10E are schematic views showing a mold release step.
[Explanation of symbols]
1, 6, 12.17, 23 Wide-mouth heat-resistant synthetic resin container
2, 14, 31 Flange 3, 19 Thick part
4, 8 Bottom 7, 13 Mouth
10 Convex part 15 Whitening part
16 Amorphous part 18, 24, 32 Body
25 bulge 30 preform
35 Lower mold 36 Halogen lamp
40 Top 41 Bottom
42 Upper mold body 43 Flange engaging part
44 Insulation 45 Projection
46 Center rod 47 Air hole
48 Blow air inlet 49 Space
50 to 52 Stretched rod 56 Center rod tip piece
60-62 longitudinal slit

Claims (12)

A blow-molded wide-mouth synthetic resin container having a flange at the opening end, the body excluding the flange is transparent and heat-resistant by heat treatment after stretching orientation, and the upper surface of the flange has heat-sealability , The container mouth part below the flange is a stretched thick part, and the bottom part is convex inward, and the synthetic resin container is formed of a thermoplastic polyester resin system and has a content of 100 ° C. A heat-resistant wide-mouth synthetic resin container characterized by having a heat resistance with a degree of deformation of less than 3% after full filling . 2. The heat-resistant wide-mouth synthetic resin container according to claim 1 , wherein the thickness of the thick portion is 2 to 4 times the thickness of the thin barrel portion and extends from the opening end to a range of 2.5 mm or more. . The heat-resistant wide-mouth synthetic resin container according to claim 1 or 2 , wherein the flange is whitened on the back side and has a high degree of crystallinity, and the surface side has an amorphous state or a low degree of crystallinity and maintains heat sealability.   Reduces heat transfer from the mold to the flange during blow molding in a mold heated at a temperature range between the glass transition temperature and the melting point, with a preform having a flange at the open end and closed bottom. In this state, the step of performing longitudinal stretching with a stretching rod, the step of performing lateral stretching, complete shaping and heat setting with air pressure, and the cooling step of blowing high-pressure air to the inner surface of the container with the stretching rod to cool below the glass transition temperature A method for producing a heat-resistant wide-mouth synthetic resin container, comprising: The process of performing lateral stretching, complete shaping and heat setting with the air pressure is a pre-blow process for lateral stretching and orientation with an air pressure of 0.7 to 1.0 MPa, and a product shape with high pressure air of 3.0 to 4.0 MPa. The method for producing a heat-resistant wide-mouthed synthetic resin container according to claim 4 , comprising a high-pressure blowing step of complete shaping and holding in a high-temperature mold to promote crystallization. The said cooling process sprays the slit-shaped high pressure air of a vertical axis | shaft direction from the vertical slit of an extending | stretching rod on a container trunk | drum internal peripheral surface, and cools to the glass transition temperature or less, The heat resistant wide-mouth synthetic resin container of Claim 4 or 5 Production method. The heat-resistant wide-mouth synthetic resin container according to any one of claims 4 to 6, further comprising a preform pretreatment step in which only the opposite side of the heat seal surface is heated to whiten the preform flange before blow molding. Method.   An apparatus for producing a heat-resistant wide-mouth synthetic resin container by blow molding, having a flange support surface for supporting a flange surface of a preform and having an opening through which a stretching rod passes in the center, An upper mold having a blow molding cavity that engages with the flange support surface side, and an extending rod, and the upper mold includes a flange engaging member that engages with the flange surface of the preform, and an upper mold body member that forms the cavity The flange engaging member is thermally connected to the upper mold main body, and the apparatus for manufacturing a heat-resistant wide-mouth synthetic resin container. 9. The apparatus for manufacturing a heat-resistant wide-mouth synthetic resin container according to claim 8 , wherein a bottom mold is provided at the bottom of the top mold so as to be movable up and down, and the bottom mold has a convex shape in the cavity. The extending rod has an air passage inside in the axial direction, a vertical slit communicating with the air passage is formed on the outer periphery of the shaft, and cooling air can be blown in the axial direction of the inner peripheral surface of the container through the vertical slit. The apparatus for manufacturing a heat-resistant wide-mouth synthetic resin container according to claim 8 or 9 formed as described above. The heat resistance according to any one of claims 8 to 10 , wherein a center rod is provided at a center portion of the bottom mold so as to be vertically movable, an air passage is formed in an axial direction of the center rod, and an air blowing hole is provided at a tip portion thereof. Equipment for flexible wide-mouth synthetic resin containers. The lower mold is configured to be rotatable while supporting the preform. The preform is rotated while supporting the preform supplied to the lower mold, and the outer periphery of the preform is heated by heating means provided outside. heat-resistant wide-mouthed plastic container manufacturing apparatus according to any one of claims 8-10.

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