JP2007290772A - Synthetic resin bottle and synthetic resin bottle manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a synthetic resin bottle capable of facilitating the reversing of a reversed portion, having high strength against cracks or slits at a hinge and positively maintaining either the recessed state or the protruding state of the reversed portion, and a synthetic resin bottle manufacturing method. <P>SOLUTION: A bottom 4 for closing the lower part of a barrel 3 is provided with legs 7 having a ground contact surface and a reversed part 8 continuously arranged at inner peripheral edges of the legs 7. The reversed part 8 has with symmetrical slant portions 11 stretched together with the barrel 3 and the legs 7 and reversed in a recess or a protrusion toward the inside of the barrel 3 and the outside of the barrel 3, and a bottom central part 13 formed at a region enclosed by the slant portions 11. A pair of biaxially oriented hinges 10, 12 becoming the hinges at the time of reversing are arranged along each of outer circumferential edges and inner circumferential edges of the slant portions 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a synthetic resin bottle filled with a liquid content such as a beverage and a method for producing a synthetic resin bottle.

  2. Description of the Related Art A biaxial stretch blow molded bottle (PET bottle) made of, for example, polyethylene terephthalate is known as a content-filling bottle that contains a liquid content such as a beverage.

  In this type of bottle, for heat sterilization, a beverage heated to a high temperature (for example, about 85 ° C.) is filled, and the mouth is sealed with a cap and then cooled. According to this, the inside of a bottle will be in a pressure-reduced state with the volume reduction of the drink by cooling. At this time, the body of the bottle may be deformed by the reduced pressure in the bottle, which is not preferable in appearance.

  For this reason, in a synthetic resin bottle filled with a liquid content at a high temperature, it is carried out to form a plurality of flexible panels in the body portion that uniformly absorb deformation caused by internal decompression (for example, Patent Document 1). However, when such a panel is provided, a large number of concave and convex shapes are required on the bottle body, which not only complicates the mold shape but also requires a relatively large amount of material. Will increase.

  Therefore, after the bottle bottom is provided with a reversing part that can be turned upside down, and the reversing part protrudes outward from the body, the heated liquid content is filled and the bottle mouth is sealed with a cap. In addition, there has been known one in which an inverted portion in a protruding state is inverted and recessed inward of a bottle during decompression by cooling (see Patent Document 2).

In the bottle described in Patent Document 2, prior to filling the liquid content, the upper pusher rod is extended from the bottle mouth toward the inside of the bottle, and the upper pusher rod pushes down the center of the inner surface of the bottom of the bottle. Is done. Thereby, the inversion part of the bottom of the bottle is inverted and protrudes outward and downward from the body part. Then, the upper pusher rod is pulled out from the inside of the bottle, and the heated liquid content is filled inside the bottle with the inverted portion at the bottom protruding outward and downward from the barrel, and then the bottle mouth is covered with a cap. Seal. After that, when the liquid content inside the bottle cools and becomes a reduced pressure state, the bottom pusher rod is pushed up from below at the center part of the lower outer surface of the bottle bottom, and the bottle bottom in a state where it protrudes downward outside the body part is inverted. The part is recessed and inverted in the inner direction of the body part. As a result, the internal pressure in the depressurized state is offset, and the decompression deformation of the body portion of the container does not occur. In this way, by providing a reversal part that can be freely reversed on the bottom of the bottle and reversing the reversal part in the liquid content filling line, the bottle body can absorb the deformation as described above evenly. There is no need to provide a panel, the degree of freedom in bottle design is improved, and the material cost of the bottle can be reduced.
JP-A-6-72423 Special table 2006-501109

  In the bottle described in Patent Document 2, it is conceivable to provide a hinge portion along the boundary of the reversal portion in order to smoothly reverse the reversal portion of the bottom portion in the liquid content filling line. However, if the reversal of the reversing part is repeated, there is a possibility that a crack or a crack may occur in the hinge part. Therefore, it is necessary to form the hinge part in a shape that is easy to bend, but on the other hand, it is difficult to maintain the inverted part in a state of protruding outward from the trunk part or indented inward of the trunk part. Therefore, there is a possibility that the reversing part will inadvertently return.

  The present invention has been made in view of the above-mentioned problems, can easily reverse the reversing portion and can give the hinge portion high strength against cracks and cracks. It is an object of the present invention to provide a synthetic resin bottle and a synthetic resin bottle manufacturing method capable of reliably maintaining the protruding state.

  In order to achieve such an object, the synthetic resin bottle of the present invention comprises a mouth, a cylindrical body biaxially stretched below the mouth, and a bottom that closes the lower part of the body. The bottom portion includes a leg portion having a grounding surface continuously provided at a lower end of the trunk portion, and a reversing portion continuously provided on an inner peripheral edge of the leg portion. In a synthetic resin bottle comprising an inclined part that can be reversed in a concave and convex shape symmetrically toward the outside, and a bottom center part formed in a region surrounded by the inclined part, the inclined part includes a trunk part and a leg. And a pair of biaxially stretched hinge portions that serve as hinges at the time of reversal along each of the outer peripheral edge and the inner peripheral edge.

  The synthetic resin bottle of the present invention is provided with the inclined portion at the reversing portion at the bottom thereof, so that a part of the bottom portion can be reversed in an inward and outward direction of the body portion. It has become. By this, after reversing the inclined part of the reversing part and filling the bottle with high-temperature liquid content in a protruding state below the body part, sealing the bottle mouth with a cap and cooling the contents The depressurized state inside the bottle can be eliminated simply by pushing the reversing part upward inside the body part and reversing the recess.

  Here, when the inversion part is inverted from the protruding state to the recessed state, or from the recessed state to the protruding state, in the synthetic resin bottle of the present invention, each of the outer peripheral edge and the inner peripheral edge of the inclined portion. By providing the hinge portion, the inclined portion can be reliably reversed. Moreover, in the present invention, since the hinge portion is biaxially stretched, the strength at the time of bending is high without hindering the ease of bending, and the hinge portion is not cracked or cracked when the reversing of the reversing portion is repeated. Occurrence can be reliably prevented. In addition, as a specific shape of the hinge part, the thickness of the hinge part is formed thinner than both sides of the hinge part, or reinforcement (thickness is increased) along both sides of the hinge part, or For example, the sectional shape of the hinge portion may be a curved shape.

  Further, in the synthetic resin bottle of the present invention, the reversing portion has a pressing force required for reversing the inclined portion by pressing the bottom center portion in the axial direction of the trunk portion to be 30 to 300 N. It is characterized by being formed.

  When the reversing part is reversed from the protruding state to the recessed state, or from the recessed state to the protruding state, it is conceivable to apply a mechanical pressing force to the center part of the bottom part in the axial direction of the body part. At this time, the pressing force required for reversing the inclined portion is such that the bottom central portion is mechanically moved in the axial direction of the trunk portion in the state of an empty bottle (a bottle not filled with contents). The inversion part is formed so as to be 30 to 300 N when pressed. By doing so, not only can it be easily reversed, but also conflicting properties such as reliably maintaining the state after inversion (indented state or protruding state) can be achieved. In other words, when the pressing force at the time of reversal is lower than 30N, when the contents are filled inside the bottle and gripped by hand or when the contents expand due to the influence of the surrounding temperature, the reversal is reversed. There is a risk. In particular, even when the load of the contents is applied to the bottom portion, the reversal portion needs to have a shape retention strength that can prevent reverse reversal. Moreover, when the pressing force at the time of reversal is higher than 300N, there is a possibility that parts other than the center portion of the bottom portion and the reversing portion that receive the mechanical pressing force are damaged. In particular, when the reversing part is reversed from the protruding state to the recessed state, it is necessary to support the shoulder part (upper end part of the body part) of the bottle, the upper edge of the mouth part, etc. and hold it against the pressing direction. However, in order to prevent damage to the portion pressed against the pressing direction, it is necessary to consider the strength of the portion other than the reverse portion. Therefore, in the present invention, the reverse portion is formed so that the pressing force at the time of reversal is 30 to 300 N as the push-up push force or push-down push force at the center of the bottom without damaging the bottle. Inversion can be performed easily and reliably, and the state after inversion (indented state or protruding state) can be reliably maintained.

  Here, in order to set the pressing force at the time of reversal of the reversing portion to 30 to 300 N, setting the diameter of each hinge portion, the thickness of the inclined portion, and the like can be mentioned. Alternatively, as a preferred mode thereof, when the inversion part is recessed in the body part, the inclination angle of the leg part with respect to the ground contact surface is 15 ° to 50 °, more preferably 20 ° to 40 °. And the inversion portion so that the moving distance of the center portion of the bottom portion is 6 to 40 mm in a state where it is recessed inwardly of the body portion and a state of protruding outwardly of the body portion. Either or both of forming can be selectively employed.

  Furthermore, in the synthetic resin bottle of the present invention, the reversal portion has a capacity change caused by the reversal of 1 to 10% with respect to the total capacity of the bottle when indented toward the inside of the body portion. Can be formed. Thereby, even when the decompression of the body part is large, it is possible to cope with the case where the decompression of the body part is small.

  Furthermore, in the synthetic resin bottle of the present invention, it is preferable that at least the inclined part of the inversion part is heat-set, thereby imparting heat resistance to the inversion part.

  Furthermore, in the synthetic resin bottle of the present invention, it is preferable that at least the inclined portion of the inversion portion is formed by laminating a layer of polyethylene terephthalate resin and gas barrier resin, whereby the inversion portion of the inversion portion is inverted. Therefore, it is possible to reliably prevent the gas barrier property of the reversing portion from being lowered.

  In addition, the method of the present invention includes a mouth portion, a cylindrical trunk portion that is biaxially stretched below the mouth portion, and a bottom portion that closes a lower portion of the trunk portion, and the bottom portion is a portion of the trunk portion. A leg portion having a grounding surface continuously provided at the lower end, and a reversing portion continuously provided on the inner peripheral edge of the leg portion, the reversing portion being extended together with the trunk portion and the leg portion, A method for producing a synthetic resin bottle comprising an inclined part that can be reversed in a symmetrical shape in a symmetrical shape toward the outside of the body part, and a bottom center part formed in a region surrounded by the inclined part, wherein the blow molding metal Blow molding process for blow molding the preform in the mold to form the body part and the bottom part, and a detaching process for removing the bottle having the body part and the bottom part formed by the blow molding process from the blow molding die And the blow molding step has the inclined portion of the bottom portion outward of the body portion. A step of biaxially stretching with a blow molding die provided with a bottom molding portion corresponding to the protruding shape, and then an inclined portion formed by the bottom molding portion prior to the removing step inside the blow molding die And a step of recessing the body part inwardly.

  According to the present invention, in the blow molding step, the reversal part is formed by a blow molding die having a bottom molding part corresponding to a shape in which the reversal part of the bottom part protrudes outward from the body part. The inclined part and the hinge part of the reversing part can be reliably biaxially stretched. Thereby, it is possible to form an inclined portion and a hinge portion that are easy to bend and have high strength, and in particular, it is possible to form a hinge portion that reliably prevents the occurrence of cracks and cracks.

  Further, in the blow molding step, it is preferable to provide a step of recessing the inclined portion formed by the bottom molding portion inward of the body portion in the blow molding die prior to the removing step. Thereby, even if the inverted portion of the bottom is formed in a shape protruding outward from the barrel by the blow molding die, when removing the bottle having the barrel and the bottom from the blow molding die, The inversion part is recessed inwardly of the trunk part, and can have the same appearance as a conventional bottle.

  An embodiment of the present invention will be described with reference to the drawings. 1A and 1B are explanatory views of the synthetic resin bottle of the present embodiment as viewed in a longitudinal section, FIG. 2 is an explanatory view of the synthetic resin bottle of the present embodiment as viewed from the bottom, and FIG. 3 is the present embodiment. FIG. 4A and FIG. 4B are explanatory views schematically showing a part of the blow molding process, and FIG. 5A and FIG. 5B are enlarged views of the bottom of the synthetic resin bottle. FIG. 6A and FIG. 6B are explanatory views showing the pushing-up operation of the reversing part.

  As shown in FIG. 1A, the synthetic resin bottle 1 according to the present embodiment includes a mouth portion 2, a cylindrical body portion 3 continuously provided below the mouth portion 2, and the body portion 3. And a bottom portion 4 for closing the lower portion. The bottle 1 is biaxially stretched and blow-molded from a preform (not shown) made of an injection-molded polyethylene terephthalate resin, whereby the body portion 3 and the bottom portion 4 are formed in a biaxially stretched state. Moreover, the bottle 1 of the present embodiment is heat set to impart heat resistance. Note that the mouth portion 2 is already crystallized in a preform state and imparted heat resistance. A screwing portion 5 for screwing a cap (not shown) is formed on the outer periphery of the mouth portion 2, and a flange portion 6 is formed on the lower portion of the screwing portion 5 so as to project to the outer periphery.

  Next, the bottom part 4 of the synthetic resin bottle 1 of this embodiment will be described in detail. As shown in FIGS. 2 and 3, the bottom portion 4 includes an annular leg portion 7 formed continuously at the lower end of the body portion 3, and an inversion portion 8 formed in a region surrounded by the leg portion 7. It has. The leg portion 7 includes an annular grounding surface 9, and the grounding surface 9 can be grounded so that the bottle 1 can be stably supported.

  The inversion part 8 is connected to the inner peripheral edge of the leg part 7 via the first hinge part 10 and is connected to the inner peripheral edge of the inclination part 11 via the second hinge part 12. And an inward projecting portion 13 (bottom center portion).

  Both the first hinge part 10 and the second hinge part 12 are biaxially stretched and formed thinner than the inclined part 11. In addition, the first hinge portion 10 has a curved sectional shape that is recessed inward of the bottle 1, and the second hinge portion 12 has a sectional shape that projects outward. Accordingly, the first hinge portion 10 and the second hinge portion 12 have a high bending strength with respect to the reversing operation while ensuring the ease of bending as a hinge.

  The inclined portion 11 is formed in a generally conical shape that is inclined inwardly from the first hinge portion 10 to the second hinge portion 12 toward the center portion of the bottom portion 4. The inclination angle θ of the inclined portion 11 is about 30 ° (15 ° to 50 °, particularly preferably 20 ° to 40 ° is preferable) with respect to the ground contact surface 9 of the leg portion 7. It is formed at a stretch ratio of about 6 times (preferably at least 1.5 times) at the time of blow molding. The inclined portion 11 has a thickness dimension of about 0.5 mm (preferably 0.2 mm to 1.0 mm), and includes a plurality of hollow lines 14 that extend substantially radially and a panel surface 15 between the hollow lines 14. It is configured. Furthermore, when heat resistance is imparted to the bottle 1, a heat setting process is performed.

  In the present embodiment, the cross-sectional view shape of the inclined portion 11 is linear, but the cross-sectional view shape of the inclined portion 11 is not limited to this, and for example, the wave shape, the inner side or the outer side of the bottle 1 A shape that curves like a bow may be adopted.

  The inward protruding portion 13 rises from the inner peripheral edge of the inclined portion 11 via the second hinge portion 12 and protrudes into the trunk portion 3 (indented when viewed from the outside), and the apex portion 16 is a flat, generally conical shape. It is formed into a shape. Further, the peripheral wall 17 of the inward projecting portion 13 is formed to have the same thickness as or thinner than the inclined portion 11, and a plurality of ribs 18 extending in the height direction are formed on the peripheral wall 17. The center of the top portion 16 of the inward projecting portion 13 substantially coincides with the axis of the bottle 1 (that is, the center of the bottom portion 4).

  Further, the size of the inward protruding portion 13 can be appropriately selected according to the outer diameter of the bottom portion 4. If the preferable range is mentioned, the diameter of the top part 16 of the inward protrusion part 13 and the lower end edge of the surrounding wall 17 with respect to the diameter of the bottom part 4 can all be selected in the range of 10%-40%. Furthermore, the inward protrusion 13 can be appropriately selected in height according to the inner volume of the bottle 1. As a preferred range, when the inner volume of the bottle 1 is 200 ml to 2000 ml, the height dimension of the selectable inner protrusion 13 (the height from the lower end edge of the peripheral wall 17 to the top 16) is 2 mm to 20 mm. It can be selected within the range.

  Further, in FIG. 3, when the top portion 16 of the inward projecting portion 13 and the reversing portion 8 are protruding downward from the body portion 3 when the reversing portion 8 is in a state of being recessed into the body portion 3. A distance L between the inward projecting portion 13 and the top portion 16 (that is, a moving distance associated with the reversal of the reversing portion 8) is 6 to 40 mm.

  And the bottom part 4 of the bottle 1 has a pressing force of 30 to 30 when the inner projecting part 13 is pressed in the axial direction of the trunk part and the inclined part is reversed as described later. 300N.

  Next, if the manufacturing method of the bottle 1 in this embodiment is demonstrated, the bottle 1 will be shape | molded by the blow molding die 19, as typically shown to Fig.4 (a) and FIG.4 (b). The mold 19 includes a body molding part 20, a bottom molding part 21, and a stretch rod 23 including an air nozzle 22. The body forming part 20 corresponds to the outer shape of the body part 3, and the bottom part forming part 21 corresponds to the shape of the bottom part 4 in a state in which the reversing part 8 protrudes downward from the body part 3. A pressing member 24 that corresponds to the outer shape of the inward protruding portion 13 and presses the inward protruding portion 13 toward the inner side of the body portion 3 is provided at the center of the bottom molding portion 21.

  In the formation of the bottle 1 by the blow molding die 19, first, a preform (not shown) is attached to the blow molding die 19, and then, as shown in FIG. Thus, biaxial stretch blow molding is performed. Thereby, the trunk | drum 3 and the bottom part 4 are formed so that it may contact | adhere to the trunk | drum molded part 20 and the bottom part molded part 21 closely. At this time, the bottom forming portion 21 corresponds to the shape of the bottom portion 4 in a state where the reversing portion 8 protrudes downward from the body portion 3, so that the reversing portion 8, that is, the inclined portion 11, The first hinge portion 10 and the second hinge portion 12 are well biaxially stretched along the bottom molding portion 21. When the bottom portion 4 is formed along the bottom molding portion 21, subsequently, the pressing member 24 presses the inward protruding portion 13 toward the inside of the trunk portion 3 as shown in FIG. To do. Thereby, the inversion part 8, that is, the inclined part 11, the first hinge part 10, and the second hinge part 12 are separated from the bottom molding part 21 and recessed into the body part 3. Thereafter, although not shown, the blow mold 19 is divided and the bottle 1 is taken out from the inside.

  The bottle 1 blow-molded as described above and taken out from the blow-molding die 19 is formed in a state in which the inversion portion 8 of the bottom portion 4 is recessed in the body portion 3 as shown in FIG. . And the bottom part 4 of the bottle 1 can project the said inversion part 8 toward the downward direction of the bottle 1, as shown in FIG.1 (b). That is, when the reversing part 8 protrudes below the body part 3 as shown in FIG. 1B from the state in which the reversing part 8 is recessed in the body part 3 as shown in FIG. As shown in FIG. 5 (a), the upper pusher rod 25 is abutted against the inward projecting portion 13 from the inside of the body portion 3 and the bottom portion 4 is pushed down. As a result, the inclined portion 11 is inverted into a symmetrical shape via the first hinge portion 10 and the second hinge portion 12 as indicated by phantom lines in FIG. 3, and the trunk portion 3 as shown in FIG. Protrudes downward.

  At this time, the reversing portion 8, that is, the inclined portion 11, the first hinge portion 10, and the second hinge portion 12 are all well biaxially stretched, so that the first hinge portion 10 is pressed by the upper pusher rod 25. And the inversion part 8 can be pushed down reliably, without the 2nd hinge part 12 being damaged. Further, since the reversing portion 8 is set so as to be able to be reversed by a pressing force of 30 to 300 N, the first hinge portion 10 is bent and at the same time the outer peripheral edge (the lower end edge of the peripheral wall 17) of the inward protruding portion 13. 2 The hinge portion 12 is bent outward in a circular arc shape in cross section and at an acute angle, and the inward projecting portion 13 is maintained in a state of projecting into the body portion 3 without being inverted. At this time, since the rib 18 is provided on the peripheral wall 17 of the inward projecting portion 13, the strength of the peripheral wall 17 of the inward projecting portion 13 is also ensured, so that the pressing force by the upper pusher rod 25 is ensured. Can be transmitted to the inclined portion 11. Further, even when the inclined portion 11 is bent at the time of starting reversal, the stress can be distributed to each panel surface 15 by being absorbed by the plurality of hollow lines 14 extending in a substantially radial manner. Can be efficiently applied to the inclined portion 11 and can be easily reversed. Furthermore, since the inclination angle θ of the inclined portion 11 is about 30 ° with respect to the ground contact surface 9 of the leg portion 7, the inclined portion 11 can be easily set by setting the pressing force by the upper pusher rod 25 within the range of 30 to 300N. In addition, the protruding state of the reversing portion 8 due to the reversal of the inclined portion 11 can be reliably maintained.

  When the reversing portion 8 is recessed inward of the trunk portion 3 as shown in FIG. 1A from the state in which the reversing portion 8 protrudes from the trunk portion 3 as shown in FIG. 6 (a), the lower pusher rod 26 is abutted against the inside of the inward projecting portion 13 from below the bottom portion 4, and the bottom portion 4 is pushed up. This operation is performed after the liquid content is filled in the bottle 1 and sealed with a cap. As a result, the inclined portion 11 is inverted toward the inside of the body portion 3 via the first hinge portion 10 and is recessed into the inside of the body portion 3 as shown in FIG. Accordingly, the inward projecting portion 13 maintains a state of projecting into the body portion 3, and the second hinge portion 12 at the outer peripheral edge (the lower end edge of the peripheral wall 17) of the inward projecting portion 13 is bent at an acute angle. Is released.

  At this time, the push-up force of the lower pusher rod 26 is evenly transmitted over the entire inner edge of the inclined portion 11 via the inward projecting portion 13, and the inclined portion 11 can be inverted and recessed with a relatively small push-up force. it can. Similarly to the case where the reversing portion 8 is projected, even if the inclined portion 11 is bent at the time of reversing, the stress is absorbed by each of the panel surfaces 15 by being absorbed by the plurality of hollow lines 14 extending substantially radially. Therefore, the pressing force at the time of reversal can be efficiently applied to the inclined portion 11. Further, since the inclination angle θ of the inclined portion 11 is about 30 ° with respect to the ground contact surface 9 of the leg portion 7, the inclined portion 11 can be reversed with a relatively small pressing force, and the reversing portion 8. The recessed state of is reliably maintained.

  In addition, although the bottle 1 of this embodiment is set so that the pressing force when the reversing unit 8 is reversed is 30 to 300 N, the pressing force set to the reversing unit 8 is the buckling strength of the bottle 1. It can be selected within the range of 30 to 300N according to the above. That is, when the buckling strength of the bottle 1 is 55 kgF or more, the pressing force set to the reversing portion 8 is 30 to 300 N, but when the buckling strength of the bottle 1 is 200 N or more, the reversing portion 8 The pressing force to be set is less than 200N.

  In addition, the inventor conducted a test on a suitable pressing force set in the reversing unit 8 according to the capacity of the bottle (the size of the bottom). As an example of the result, it has been found that it is particularly suitable for an empty bottle with a capacity of 300 ml and 500 ml to have the reversing portion 8 protruding at 120 to 180 N and recessed at 80 to 130 N.

  Further, when the bottle 1 of this embodiment is used for so-called hot pack type filling in which the heated liquid content is filled and sealed, the inside of the bottle 1 is reduced in pressure by the reversing unit 8 as the temperature of the liquid content decreases. Although it can be eliminated by recessing, it is not limited to this, and even when used for so-called aseptic filling in which liquid content is filled and sealed at room temperature, the liquid content is cooled at low temperature. It is possible to eliminate the relatively small pressure reduction in the bottle 1 due to. That is, with reference to FIG. 3, when the bottle 1 is used for aseptic filling, the diameter of the first hinge portion 10 is reduced and the position is changed to the inside of the bottom portion 4 to change the inclined portion. The capacity of the bottle 1 associated with the inversion of the inversion part 8 is reduced by reducing the width of the eleventh part (the interval between the first hinge part 10 and the second hinge part 12) or by reducing the angle of the inclined part 11 with respect to the ground plane 9. Change should be small. By such a method, the change in the capacity of the bottle 1 accompanying the reversal of the unevenness of the reversing unit 8 can be easily changed within a range of 1% to 10% with respect to the total capacity of the bottle 1. When the bottle 1 is used for aseptic filling, the bottle 1 need not be heat set.

  Further, the bottle 1 according to the present embodiment is taken out from the blow molding die 19 in a state in which the reversing portion 8 protrudes downward from the body portion 3 as shown in FIG. The shape shown in (b) can be used up to filling with contents and sealing with a cap. In this case, since the reversing part 8 protrudes below the leg part 7 and the second hinge part 12 is located below the ground surface 9 and it is difficult to carry the bottle 1 in a self-standing state, It is necessary to transport the bottle 1 by attaching an appropriate bottom protection member or by gripping the mouth 2 of the bottle 1. Further, even when the inversion portion 8 protrudes downward from the trunk portion 3, the bottom portion 4 is formed in a shape in which the second hinge portion 12 is positioned above the ground plane 9 in that state. Thus, the bottle 1 can be transported in a self-supporting state.

  In addition, after blow molding, the bottle 1 according to the present embodiment may be coated with an amorphous carbon film or a silicon oxide-containing film on the inner surface of the bottle 1 by plasma deposition in order to improve barrier properties such as oxygen and carbon dioxide gas. it can. At this time, it is considered that the gas barrier property is lowered due to the reversing operation in the inclined portion 11 of the reversing portion 8, but at least the inclined portion 11 is made of a synthetic resin having a high gas barrier property such as polyethylene naphthalate or MX nylon. By laminating in multiple layers, it is possible to prevent the gas barrier property from being lowered due to the reversing operation. In the bottle 1 provided with a layer of synthetic resin having a high gas barrier property, the synthetic resin having a high gas barrier property is injected into the bottom of the preform in a layered manner at the stage of molding the preform by injection molding. The bottle 1 can be easily obtained by blow molding by the manufacturing method according to the present embodiment.

Explanatory drawing which looked at the synthetic resin bottle of one Embodiment of this invention in the longitudinal cross-section. Explanatory drawing which looked at the bottom of the synthetic resin bottle of this embodiment. Cross-sectional explanatory drawing which expands and shows the bottom part of the synthetic resin bottles of this embodiment. Explanatory drawing which shows a part of blow molding process typically. Explanatory drawing which shows the pushing-down operation | work of an inversion part. Explanatory drawing which shows the pushing-up operation | work of an inversion part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Synthetic resin bottle, 2 ... Mouth part, 3 ... Body part, 4 ... Bottom part, 7 ... Leg part, 8 ... Inversion part, 9 ... Grounding surface, 10 ... 1st hinge part (hinge part), 11 ... Inclination , 12 ... second hinge part (hinge part), 13 ... inward projecting part (bottom center part), 19 ... blow molding die, 21 ... bottom part molding part.

Claims (9)

A grounding surface provided with a mouth portion, a cylindrical trunk portion biaxially extended below the mouth portion, and a bottom portion that closes a lower portion of the trunk portion, the bottom portion being connected to a lower end of the trunk portion And a reversing part connected to the inner peripheral edge of the leg part, the reversing part is a slanted part that can be reversed in a concave and convex shape symmetrically toward the inner part of the trunk part or outward of the trunk part, In a synthetic resin bottle provided with a bottom center portion formed in a region surrounded by the inclined portion,
The inclined portion includes a pair of biaxially extended hinge portions that are extended together with the body portion and the leg portions, and that serve as hinges at the time of reversal along each of the outer peripheral edge and the inner peripheral edge. A synthetic resin bottle.   The reversing part is formed so that a pressing force required for reversing the inclined part by pressing the bottom center part in the axial direction of the body part is 30 to 300N. Item 6. A synthetic resin bottle according to item 1.   The inclined portion is formed so that an inclination angle of the leg portion with respect to a ground contact surface is 15 ° to 50 ° when the inversion portion is recessed inward of the trunk portion. Item 3. A synthetic resin bottle according to item 1 or 2.   The reversing part is formed such that a moving distance of the bottom center part is 6 to 40 mm in a state where the reversing part is recessed inward of the body part and a state of protruding toward the outside of the body part. The synthetic resin bottle according to any one of claims 1 to 3.   The said inversion part is formed so that the capacity | capacitance change accompanying the inversion may be 1 to 10% with respect to the bottle total capacity | capacitance when it is in a recessed state toward a trunk | drum inner part. Item 5. A synthetic resin bottle according to any one of Items 1 to 4.   The synthetic resin bottle according to any one of claims 1 to 5, wherein at least the inclined portion of the inversion portion is heat-set to impart heat resistance.   The synthetic resin bottle according to any one of claims 1 to 6, wherein a polyethylene terephthalate resin and a gas barrier resin are laminated in a layered manner at least in the inclined portion of the inversion portion. A grounding surface provided with a mouth portion, a cylindrical trunk portion biaxially extended below the mouth portion, and a bottom portion that closes a lower portion of the trunk portion, the bottom portion being connected to a lower end of the trunk portion And a reversing portion connected to the inner periphery of the leg. The reversing portion is extended together with the trunk portion and the leg portion and is symmetric toward the inside of the trunk portion or the outside of the trunk portion. A method of manufacturing a synthetic resin bottle comprising an inclined part that is reversibly concave and convex in shape, and a bottom center part formed in a region surrounded by the inclined part,
A blow molding process in which a preform in a blow molding mold is blow molded to form the body and bottom, and a bottle having the body and bottom formed by the blow molding process is removed from the blow molding mold. A removal process to remove,
The blow molding step includes a step of biaxially stretching with a blow molding die having a bottom molding portion corresponding to a shape in which the inverted portion of the bottom portion protrudes outward from the body portion. Manufacturing method of resin bottles.   9. The blow molding step includes a step of recessing an inclined portion formed by the bottom molding portion inward of the body portion in the blow molding die prior to the removing step. Of manufacturing a synthetic resin bottle.

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