JP2008007132A - Plastic bottle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plastic bottle which has no possibility of the buckling deformation of a body caused by a vertical load and an impact applied on a mouth when a content is filled into the bottle at a high temperature or a stopper is plugged after filling, and no possibility of deforming abnormally caused by a reduced-pressure state by cooling the content filled in the bottle. <P>SOLUTION: The plastic bottle composed of the mouth 11, a cylindrical body 12 and a bottom 13 is prepared by bi-axially oriented blow-molding. A buckling reinforcing part 3 composed of a plurality of stripes of annular recessed channels 15 continuous in the peripheral direction is formed on the upper part of the body 12. The outer diameter and the thickness of the buckling reinforcing part 3 are formed to be 74-76 mm, and 0.20-0.35 mm, respectively. The annular recessed channel 15 is formed into an approximately ridge-like cross-section with a depth of 1.0-1.5 mm, and upper and lower parts of the channel are continuous to the outer face of the body with smooth curved faces. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a plastic bottle formed by biaxial stretch blow molding of a polyethylene terephthalate resin or the like, and more specifically, when the contents are filled in the bottle or when the bottle is plugged after filling the contents, the vertical is applied to the bottle. With a buckling reinforcement that prevents buckling deformation due to load (load from the top surface of the bottle axial direction) and impact, and when the filled and sealed contents cool down and the bottle is depressurized The present invention relates to a plastic bottle provided with a reduced pressure absorbing portion that prevents abnormal deformation.

Plastic bottles obtained by biaxial stretching of polyethylene terephthalate resin are widely used as containers for seasonings such as various beverages and sauces because they are thin and lightweight. When filling the contents into such a plastic bottle or when plugging the cap into the bottle mouth after filling the contents, the bottle body may buckle and deform due to the vertical load or impact applied to the mouth. is there. For this reason, the conventional plastic bottle is provided with a buckling reinforcement portion having a plurality of annular concave grooves continuous in the circumferential direction at appropriate positions of the body portion. In addition, when the contents cool down after filling and sealing the hot contents, the inside of the bottle may be in a decompressed state and the bottle may be deformed. (See, for example, Patent Documents 1 and 2).
Japanese Utility Model Publication No. 56-118806 Japanese Patent Laid-Open No. 2005-75408

  In the conventional plastic bottle, by providing a deep annular groove in the buckling reinforcement part, the vertical load and impact applied to the mouth from above are absorbed and relaxed by this annular groove, but if the annular groove is too deep This part becomes a neck and the bottle body is likely to buckle and deform. On the other hand, if the annular groove is too shallow, the rib effect of the annular groove will be lost, so the rigidity of the barrel wall surface will be reduced, and it will deform into a flat shape when gripped by hand, Even without applying an external force, when the inside of the bottle is in a reduced pressure state due to the temperature drop of the contents after filling and sealing, the bottle may be deformed into a flat shape.

  Immediately after filling and sealing the high temperature contents, the inside of the bottle is heated to a positive pressure state, and the vacuum absorbing panel formed on the bottle protrudes and deforms from the surface of the bottle body, and then the temperature of the contents decreases. Since the inside of the bottle is in a reduced pressure state due to the density change accompanying the above, the protruded reduced pressure absorption panel is in a state of being recessed from the surface of the bottle body. This vacuum absorption panel has a higher vacuum absorption capacity as the movable amount from the protruded state to the recessed state increases, and absorbs the positive pressure when the bottle is filled with high-temperature contents and the reduced pressure after cooling. Can be relaxed. However, if the movable amount is too large, all the panels may not return to the recessed state during decompression. That is, a part of the panel that protrudes from the surface of the bottle body at the positive pressure is held as it is, so that the product has a poor appearance.

  Therefore, conventionally, the vacuum absorbing panel is provided with a substantially flat surface or a concave surface or a concave surface at the center of the vacuum absorbing panel so as not to cause the vacuum absorbing panel to protrude. Since the reduced pressure absorption capacity decreases, the reduced pressure absorption panel alone cannot secure a sufficient reduced pressure absorption amount, and the bottle may be deformed to lower the bottle strength.

  Therefore, the present invention prevents the buckling deformation by effectively absorbing and relaxing the vertical load and impact applied to the mouth from above when filling the bottle with hot contents and stoppering. In addition, an object of the present invention is to provide a plastic bottle that can absorb this pressure change and prevent abnormal deformation of the bottle when the filled and sealed high-temperature contents are cooled and the inside of the bottle is depressurized. It is said.

  In order to achieve the above object, in the first configuration, the present invention is a plastic bottle by biaxial stretch blow molding comprising a mouth portion (11), a cylindrical body portion (12), and a bottom portion (13), A buckling reinforcement part (3) having a plurality of annular concave grooves (15) continuous in the circumferential direction is formed on the upper part of the body part (12), and the outer diameter of the buckling reinforcement part (3) is 74. Each of the annular grooves (15) is formed in a substantially square shape with a depth of 1.0 to 1.5 mm, and the upper and lower sides thereof are formed with a thickness of .about.76 mm and a thickness of 0.20 to 0.35 mm. It is characterized by a smooth curved surface that continues to the outer surface of the body.

  In the second configuration, it is a plastic bottle by biaxial stretch blow molding comprising a mouth portion (11), a cylindrical barrel portion (12) and a bottom portion (13), and in the approximate center of the barrel portion (12), A neck portion (2) having a smaller diameter than the body portion, and a buckling reinforcement portion (3) provided with a plurality of annular grooves (15) continuous in the circumferential direction above the neck portion (2); The buckling reinforcement portion (3) has an outer diameter of 74 to 76 mm and a wall thickness of 0.20 to 0.35 mm, and the annular groove (15) has a depth of 1.0 to 1.5 mm. A vacuum absorbing part (4) which is formed in a substantially rectangular shape in cross section and is continuous with the outer surface of the body part with a smooth curved surface, and is provided with a plurality of vacuum absorbing panels (20) below the constricted part (2). The vacuum absorbing panel (20) is formed with a peripheral edge inclined from the outer surface of the body portion and recessed into the bottle. And (21), is characterized in that it is surrounded by the peripheral edge (21) and a panel portion that bulges (22) in an arc shape to the outer bottle.

  In the third configuration, the panel portion (22) is located on the convex curved surface (22a) that bulges out in an arc shape outside the bottle in the circumferential direction, and on the upper and lower portions of the convex curved surface (22a). In the longitudinal direction, it is inclined from the peripheral edge to the inside of the bottle and connected to the convex curved surface (22a), and in the circumferential direction, a convex restoration surface (22b) bulging out from the bottle outside in an arc shape. ).

  In the plastic bottle of the present invention, the outer diameter of the buckling reinforcing portion is set to 74 to 76 mm, the wall thickness is set to 0.20 to 0.35 mm, and the depth of the annular groove is set to 1.0 to 1.5 mm. Since the cross section is formed in a substantially square shape and the upper and lower sides of the opening side are made continuous with the outer surface of the body with a smooth curved surface, high-temperature contents in the bottle, for example, sterilized and heated sauce around 50 to 85 ° C. When filling and seasoning with a seasoning, the vertical load or impact applied to the mouth from above is effectively absorbed and relaxed by the annular groove, so that the body does not buckle. In addition, the rib effect due to the presence of the annular concave groove in the body portion increases the rigidity of the body portion, and there is no problem that the body portion deforms into a flat shape even when the body portion is gripped by hand.

  Furthermore, the plurality of reduced pressure absorption panels provided at the lower part of the bottle are formed of a peripheral edge inclined to the inside of the bottle and a panel part that is surrounded by the peripheral edge and bulges in an arc shape outside the bottle. By providing a convex curved surface and a convex restoring surface at the part, the bottle is filled and sealed with high-temperature contents, and when the bottle is in a positive pressure state, it consists of a convex curved surface and a convex restoring surface. A panel part protrudes from the surface of a bottle trunk | drum, elastically deforming by using a peripheral part as a fulcrum, and the positive pressure in a bottle is absorbed and relieved. At this time, the boundary line between the convex curved surface and the convex restoration surface becomes an inflection point, and excessive protrusion of the panel portion can be suppressed. For changes in density due to cooling of the hot-filled contents, the convex restoring surface is recessed inside the bottle by the restoring action of the convex restoring surface located above and below the convex curved surface, and the convex curved surface is the bottle. All the panel parts are restored to the initial state by being recessed inward. Furthermore, when the temperature of the contents drops to normal temperature, the inside of the bottle becomes negative pressure, but the entire panel portion having a shape bulging in an arc shape with respect to the circumferential direction is drawn into the inside of the bottle. It deforms into a flat or concave curved surface, and the reduced pressure in the bottle is absorbed and relaxed.

  For this reason, the protrusion deformation of the decompression absorption panel and the flattening of the whole bottle which are generated in the conventional plastic bottle are prevented, and a good appearance shape is maintained.

  1 is a partial cross-sectional front view of a plastic bottle showing an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of a buckling reinforcement portion, FIG. 3 is a cross-sectional view taken along line III-III in FIG. It is IV-IV sectional view taken on the line.

  The plastic bottle 1 is a so-called PET bottle in which a parison made of polyethylene terephthalate resin is biaxially stretched and blow-molded, and includes a mouth portion 11, a cylindrical body portion 12, and a bottom portion 13. A constricted portion 2 having a smaller diameter than the trunk portion 12 is provided at the approximate center of the trunk portion 12. A buckling reinforcing portion 3 is formed above the constricted portion 2, and a decompression absorbing portion 4 is disposed below the constricted portion 2. Is provided. In the vicinity of the bottom portion of the body portion 12, a reinforcing bottom annular groove 14 is provided.

  The buckling reinforcement part 3 becomes a hand grip part, and is a place where labels such as contents and manufacturer names are affixed. The bottle 1 can be tilted by grasping the buckling reinforcement part 3 by hand. Thus, the contents are extracted. The buckling reinforcing portion 3 is provided with a plurality of annular concave grooves 15 at substantially equal intervals in the vertical direction. Although the space | interval P of the upper and lower sides of the annular groove 15 can be suitably set according to the height of a bottle and the outer diameter of a trunk | drum, it is good to set normally in the range of 12-17 mm.

  In FIG. 2, the annular groove 15 is formed in a cross-sectional shape having a groove depth H of 1.0 to 1.5 mm, preferably 1.2 to 1.4 mm. The radius of curvature R1 of the part is set to 0.5 to 1.0 mm. It is preferable that the upper and lower sides of the annular groove 15 are connected to the outer surface of the cylindrical body with a smooth curved surface with a curvature radius R2 of 2.0 to 4.0 mm. The annular groove 15 satisfying such conditions is suitable for a bottle whose outer diameter D of the buckling reinforcement portion 3 is 74 to 76 mm and whose wall thickness T is 0.20 to 0.35 mm. The vertical load and impact applied to the mouth from above are effectively absorbed and relaxed by the annular groove 15 and the rigidity of the body 12 is enhanced by the rib effect due to the presence of the annular groove 15 in the body 12. Even when the body 12 is gripped by hand, the problem that the body deforms into a flat shape does not occur. When the wall thickness of the buckling reinforcing portion 3 is less than 0.20 mm, the body portion buckles and deforms due to a vertical load or impact applied to the mouth portion 11 from above during filling and sealing, and conversely exceeds 0.35 mm. This is against the trend of technology to make the bottles as thin and light as possible, which increases the product cost.

  The buckling deformation of the body portion 12 that occurs when the contents are filled and sealed is more likely to occur as the thickness of the body portion 12 becomes thinner, and becomes more noticeable as the temperature of the contents to be filled becomes higher. Normally, this buckling deformation is caused by the constricted annular groove 15 as a neck, and if the groove of the annular groove 15 is deepened, the vertical load and impact cannot be absorbed and the buckling deformation occurs. Has been confirmed. As a result, if the groove of the annular groove 15 is made shallower, the compressive strength is increased. However, if the groove is made too shallow, the rib effect by the annular groove 15 is lowered, thereby reducing the rigidity of the body part 12 and making the body part 12 flat. It becomes easy to deform. In response to this contradictory problem, in the present invention, in a bottle in which the outer diameter D of the buckling reinforcement portion 3 is limited to 74 to 76 mm, when the thickness T is reduced to 0.20 to 0.35 mm, an experiment or the like is performed. Thus, the optimum value of the groove depth of the annular groove 15 was found. Below, the experimental example which compared the groove depth of the annular groove and the compressive strength is shown.

  Two types of bottles (Examples 1 and 2) based on the present invention having a capacity of 1070 ml, a height of 260 mm, and a body outer diameter of 75 mm by biaxially stretching and blowing a parison (weight 35 g) made of polyethylene terephthalate resin Manufactured and compared with a conventional plastic bottle (Comparative Example 1). As is clear from the table below, it was confirmed that the compressive strength increased as the groove depth of the annular groove decreased.

Groove depth of annular groove (mm) Compressive strength (N)
Comparative Example 1 1.80 200.3
Example 1 1.50 257.3
Example 2 1.30 295.7

  The reduced pressure absorption part 4 is composed of six reduced pressure absorption panels 20 provided at equal intervals in the circumferential direction of the bottle. The reduced pressure absorption panel 20 has a peripheral portion 21 that is inclined from the outer surface of the body portion and is recessed inside the bottle, and a panel portion 22 that is surrounded by the peripheral portion 21 and bulges out in an arc shape outside the bottle. The portion 22 has a convex curved surface 22a that bulges in an arc shape outside the bottle with respect to the circumferential direction, and is positioned above and below the convex curved surface 22a, and from the peripheral portion to the inside of the bottle in the vertical direction. In addition to being inclined and connected to the convex curved surface 22a, there is provided a convex restoring surface 22b that bulges out in an arc shape outside the bottle in the circumferential direction.

  The thickness of the reduced pressure absorbing portion 4 can be reduced to 0.20 to 0.35 mm, similarly to the thickness of the buckling reinforcing portion 3. The plastic bottle of the present embodiment has the decompression absorbing portion 4 set to the above-mentioned thickness, and is provided with a panel portion 22 having an elastic restoring function inside the peripheral edge portion 21. The circumferential curvature of the shape restoring surface 22b can be arbitrarily set as long as it is equal to or less than the curvature of the bottle body surface, and the recess (depth) of the panel portion 22 inside the bottle by the peripheral edge portion 21 is set to 1 mm to several mm. can do.

  When the bottle 1 having such a reduced pressure absorption panel 20 is filled and sealed with high-temperature contents, the inside of the bottle is heated to a positive pressure state, so that the panel portion 22 protrudes from the surface of the bottle body portion. That is, the panel portion 22 composed of the convex curved surface 22a and the convex restoration surface 22b has the peripheral edge portion 21 as a fulcrum and protrudes from the surface of the bottle body while being elastically deformed, and the positive pressure in the bottle is absorbed and relaxed. At this time, the boundary line 22c between the convex curved surface 22a and the convex restoration surface 22b becomes an inflection point, and excessive protrusion of the panel portion 22 is suppressed.

  And, for the density change due to cooling of the high temperature filled contents, the convex restoring surface 22b is recessed inside the bottle by the restoring action of the convex restoring surface 22b located above and below the convex curved surface 22a, When the convex curved surface 22a is recessed inside the bottle, all the panel portions 22 are restored to the original state. When the temperature of the contents further decreases to normal temperature, the inside of the bottle becomes negative pressure, but the entire panel portion 22 having a shape bulging in an arc shape with respect to the circumferential direction is drawn into the inside of the bottle. By deforming into a flat or concave curved surface, the reduced pressure in the bottle is absorbed and relaxed.

  Thereby, the protrusion deformation of the reduced pressure absorption panel 20 due to the positive pressure in the bottle when the contents are filled with high temperature and sealed, and the reduced pressure deformation of the plastic bottle 1 due to the negative pressure in the bottle after being cooled are ensured. Can be prevented.

  The number and size of the reduced pressure absorption panel 20 can be set arbitrarily and can be appropriately selected according to the capacity of the bottle 1 or the density change due to cooling of the high temperature filled contents. The total surface area of 20 is set to be about 1/3 of the entire surface area of the bottle, and the vertical length B of the upper and lower convex restoring surfaces 22b is the vertical length A of the convex curved surface 22a. It is good to set it to about 1/3 of.

It is a partial section front view of the plastic bottle which shows one example of the present invention. It is an expanded sectional view of a buckling reinforcement part. FIG. 3 is a sectional view taken along line III-III in FIG. 1. It is the IV-IV sectional view taken on the line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Bottle, 2 ... Constriction part, 3 ... Buckling reinforcement part, 4 ... Decompression absorption part, 11 ... Mouth part, 12 ... Trunk part, 13 ... Bottom part, 15 ... Annular groove, 20 ... Decompression absorption panel, 21 ... Peripheral part, 22 ... Panel part, 22a ... Convex curved surface, 22b ... Convex restoration surface, 22c ... Boundary surface

Claims (3)

A plastic bottle by biaxial stretch blow molding comprising a mouth portion (11), a cylindrical barrel portion (12) and a bottom portion (13), and a plurality of strips continuous in the circumferential direction on the upper portion of the barrel portion (12). A buckling reinforcement part (3) having an annular groove (15) is formed, and the buckling reinforcement part (3) has an outer diameter of 74 to 76 mm and a wall thickness of 0.20 to 0.35 mm. The plastic is characterized in that the annular groove (15) is formed in a substantially cross-sectional shape with a depth of 1.0 to 1.5 mm, and its upper and lower sides are connected to the outer surface of the body part with a smooth curved surface. Bottle. A plastic bottle by biaxial stretch blow molding comprising a mouth portion (11), a cylindrical barrel portion (12), and a bottom portion (13), and having a diameter smaller than that of the barrel portion at substantially the center of the barrel portion (12). A constricted portion (2) is provided, and a buckling reinforcing portion (3) having a plurality of annular concave grooves (15) continuous in the circumferential direction above the constricted portion (2) is formed, and the buckling reinforcing portion ( 3) The outer diameter of 74 to 76 mm and the thickness of 0.20 to 0.35 mm are formed, respectively, and the annular groove (15) has a substantially cross-sectional shape with a depth of 1.0 to 1.5 mm. And forming a reduced-pressure absorption part (4) having a plurality of reduced-pressure absorption panels (20) below the constricted part (2), and forming the reduced-pressure absorption part (4) below the constricted part (2). The absorbent panel (20) includes a peripheral edge portion (21) inclined from the outer surface of the trunk portion and recessed inside the bottle, Plastic bottles, characterized in that it is surrounded by the rim (21) has panel which bulges in a circular arc shape outer bottle and (22). The panel portion (22) is located on the convex curved surface (22a) that bulges outside the bottle in an arc shape with respect to the circumferential direction, and on the upper and lower portions of the convex curved surface (22a). Is inclined from the periphery to the inside of the bottle and connected to the convex curved surface (22a), and has a convex restoration surface (22b) that bulges out in an arc shape outside the bottle in the circumferential direction. The plastic bottle according to claim 2.

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