JP2009078844A - Plastic bottle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lightweight plastic bottle of 500 ml which is manufactured, without forming a partially thin-walled portion in a barrel part, and has the required buckling strength in the vertical direction, and ensures applicability to vending machines. <P>SOLUTION: The plastic bottle comprises a mouth part 8, a support ring 8a, a shoulder part 9, a barrel part 10 and a bottom part 11. The barrel part 10 comprises four flat wall parts 12, and corner parts 13 connecting the flat wall parts 12. An annular circumferential groove 14, across the flat wall parts 12 and the corner parts 13, is formed. The flat wall parts 12 are divided into upper flat wall parts 12a and lower flat wall parts 12b by the circumferential groove 14. A longitudinal groove 15 is formed, in an area of the corner parts 13 which is close to the circumferential groove 14. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a plastic bottle, and more particularly to a lightweight plastic bottle satisfying sufficient strength.

In general, plastic bottles made of polyester, polypropylene, nylon or the like are known. As this type of plastic bottle molding preform, a 2000 ml bottle molding preform (Parison) is known. (See Patent Document 1).
However, when reducing the weight of plastic bottles, the maximum thickness of the preform must be reduced. When the maximum thickness of the preform is reduced, the maximum thickness portion of the preform is easily stretched during blow molding, and the bottle body is thin.
Further, in a stretch blow molding method for forming a plastic bottle having a mouth portion, a shoulder portion, a body portion and a bottom portion by subjecting a bottomed cylindrical preform having a weight of 26 g to stretch blow molding at a predetermined temperature, , At least a predetermined portion corresponding to the center of the body portion of the plastic bottle is heated at a temperature higher than the heating temperature of the other portion, and the preform is blown in a single step to thereby heat the portion heated at a temperature higher than the heating temperature of the other portion. By stretching the resin and forming at least one thin part in the central part of the body of the plastic bottle, a 500 ml plastic bottle reduced in weight while ensuring the vendor suitability is manufactured (Patent Literature). 2).
However, there is a limit to reducing the weight by partially forming a thin portion. In addition, the buckling strength in the vertical direction is reduced by reducing the thickness of the central wall of the body portion.
The packaging container is transported to a store or a vending machine in a state in which a plurality of plastic bottles packed in a pallet are stacked. At that time, if the packaging container does not have sufficient buckling strength, the packaging container may be subjected to a load in the vertical direction to cause buckling deformation.
Furthermore, a container having a neck portion, a shoulder portion, a trunk portion (upper), a waist portion (circumferential groove), a trunk portion (lower), a bottle heel portion, and a bottom portion is known. Further, in this container, it has been proposed to make the thickness of the waist part thicker than other parts (see Patent Document 3).
However, when the container described in Patent Document 3 is uniformly thinned as a whole, it is difficult to completely eliminate the possibility of buckling deformation in the waist due to a load in the vertical direction.
JP 2003-53823 A (paragraph 0042) JP 2004-66624 A (Claim 1 and paragraph 0031) Japanese Patent Laying-Open No. 2005-67683 (paragraphs 0035 and 0042)

  An object of the present invention is to produce a 500 ml plastic that has a necessary vertical buckling strength and is lightened while ensuring the bender suitability, which is manufactured without partially forming a thin portion in the body portion. Is to provide a bottle.

  Invention of Claim 1 solves said subject, It is provided with a plug part, a support ring, a shoulder part, a trunk | drum, and a bottom part, and a trunk | drum from the corner part which connects four flat wall parts and a flat wall part. In a plastic bottle having an annular circumferential groove that crosses the flat wall portion and the corner portion, and the flat wall portion is divided into an upper flat wall portion and a lower flat wall portion by the circumferential groove, the corner portion close to the circumferential groove is formed. The gist of the present invention is a plastic bottle characterized in that longitudinal grooves are formed in the region.

  In the plastic bottle according to claim 1, since the vertical groove is engraved in the area of the corner portion near the circumferential groove, the plastic bottle is a state in which a plurality of plastic bottles packed in a pallet are stacked. In the process of being transported to a store or vending machine, the corner area with the vertical grooves acts as a buffer spring. It has sufficient load resistance to withstand and does not cause deformation. In particular, when a product is stored directly in a bender, the plastic bottles laid down are placed in a vertically stacked state, but even in this placed state, they can withstand lateral loads and deform. There is no fear. Further, the plastic bottle of the present invention is resistant to the impact received when the plastic bottle is dispensed from the bender bar and dropped onto the shooter, and no deformation occurs.

  In the present invention, the upper flat wall portion is formed in an isosceles trapezoid, the lower flat portion is formed in an inverted isosceles trapezoid, and the region of the corner portion corresponding to the short side of the upper flat wall portion and the lower flat wall portion is circular. It is desirable to form in an arcuate curved part (claim 2).

  The arcuate curved portion formed in the corner region corresponding to the short side of the upper flat wall portion and the lower flat wall portion acts as a buffer spring, and at the same time, the corner region where the longitudinal grooves are engraved. It acts as a buffer spring, further improving the lateral load resistance of the plastic bottle.

In the present invention, the ratio of the depth of the longitudinal grooves to the depth of the circumferential grooves is preferably 1 to 1.5. When the ratio of the depth of the longitudinal grooves to the depth of the circumferential grooves is less than 1, it is undesirable because the plastic bottle is deformed when subjected to a vertical load. On the other hand, when the ratio of the depth of the longitudinal groove / the depth of the circumferential groove is larger than 1.5, the formability (ease of bottle swelling) at the time of blow molding deteriorates, which is not desirable. .

    In the present invention, the weight per unit volume of the plastic bottle can be 0.036 g / ml to 0.048 g / ml. Since the weight of the resin can be reduced in this way, the manufacturing cost can be made lower than before and a cheaper plastic bottle can be provided.

The plastic bottle of the present invention includes a spout part, a support ring, a shoulder part, a body part, and a bottom part, and the body part includes four flat wall parts and a corner part connecting the flat wall parts, and the flat wall part and the corner part. In a plastic bottle with an annular circumferential groove that crosses the flat wall, and the flat wall is divided into an upper flat wall and a lower flat wall by the circumferential groove, a vertical groove is engraved in the corner area near the circumferential groove. In the process of transporting plastic bottles packed in pallets to a store or a vending machine, the vertical grooves are engraved. The area of the corner portion provided functions as a buffer spring, has sufficient load resistance to withstand a load in the vertical direction, and does not cause deformation. In particular, when a product is stored directly in a bender, the plastic bottles laid down are placed in a vertically stacked state, but even in this placed state, they can withstand lateral loads and deform. There is no fear. Further, the plastic bottle of the present invention is resistant to the impact received when the plastic bottle is dispensed from the bender bar and dropped onto the shooter, and no deformation occurs. Therefore, it becomes possible to reduce the weight of the bottle by ensuring the vertical buckling strength and vendor suitability. Furthermore, the upper flat wall portion is formed into an isosceles trapezoid, the lower flat portion is formed into an inverted isosceles trapezoid, and the corner region corresponding to the short side of the upper flat wall portion and the lower flat wall portion is curved in an arc shape. By forming it in the part, the arcuate curved part formed in the corner area corresponding to the short side of the upper flat wall part and the lower flat wall part acts as a buffer spring, and at the same time the longitudinal groove is engraved The region of the corner portion thus formed serves as a buffer spring, and the load resistance of the plastic bottle is further improved.
As a result, according to the present invention, it was manufactured without partially forming a thin portion in the body portion, and had the necessary vertical buckling strength, and reduced in weight while ensuring vendor suitability. A packaging container can be provided.

  FIG. 1 is a side view of the plastic bottle of the present invention. FIG. 2 is an end view taken along line AA shown in FIG. FIG. 3 is an end view taken along line BB shown in FIG. 4 is a cross-sectional view taken along line CC shown in FIG. FIG. 5 is an end view taken along line DD shown in FIG. FIG. 6 is a perspective view showing a corner portion of the plastic bottle of the present invention.

  The plastic bottle of the present invention includes a spout part 8, a support ring 8 a, a shoulder part 9, a trunk part 10, and a bottom part 11, and the trunk part 10 includes four flat wall parts 12 and a corner part 13 that connects the flat wall parts 12. And a plastic bottle having an annular circumferential groove 14 that crosses the flat wall portion 12 and the corner portion 13, and the flat wall portion 12 is divided into an upper flat wall portion 12a and a lower flat wall portion 12b by the circumferential groove 14. A longitudinal groove 15 is engraved in the region of the corner 13 close to the circumferential groove 14 to a depth of 0.5 to 2 mm, preferably 1 mm. Furthermore, the upper flat wall portion 12a is formed in an isosceles trapezoid, and the lower flat portion 12b is formed in an inverted isosceles trapezoid. A region of the corner portion 13 corresponding to the short side of the upper flat wall portion 12a and the lower flat wall portion 12b is formed in an arcuate curved portion 17.

In the plastic bottle of the present invention, the vertical groove 15 is engraved in the area of the corner portion 13 close to the circumferential groove 14, so that the plastic bottle is in a state where a plurality of plastic bottles packed in a pallet are stacked. In the process of transporting to a store or a vending machine, the area of the corner 13 where the longitudinal grooves 15 are engraved acts as a buffer spring, and the plastic bottle receives a load from the adjacent plastic bottle. However, it has sufficient load resistance to withstand it and does not deform. In the state in which the region of the corner portion 13 in which the longitudinal groove 15 is formed has a buffering spring action and is loaded on the bender bar in the vending machine, the plastic bottle bears a load resistance to withstand the load from the adjacent plastic bottle. It has sufficient properties and does not cause deformation. In particular, in the case of direct-product-type product storage in a vendor, the plastic bottles laid down are placed in a vertically stacked state, but there is no risk of deformation even in this placed state. Furthermore, the arcuate curved portion 17 is formed by forming a region of the corner portion corresponding to the short side of the upper flat wall portion 12a of the isosceles trapezoid and the lower flat portion 12b of the inverted isosceles trapezoid in the arcuate curved portion 17. At the same time, the region of the corner portion 13 where the longitudinal groove 15 is engraved acts as a buffer spring, and the load resistance of the plastic bottle is further improved.

  The longitudinal groove 15 absorbs a buckling load when a load is applied to the plastic bottle in the vertical direction. Moreover, when the pressure inside the packaging container is reduced, when the packaging container is deformed, the internal pressure in the packaging container is absorbed and the shape of the packaging container is restored to the original cylindrical shape.

  Further, the upper flat wall portion 12a and the lower flat portion 12b are formed with a buckling load absorbing panel 16a and a buckling load absorbing panel 16b having a depth of 0.5 to 2 mm, preferably 1 mm. Ribs 18 are provided on the buckling load absorbing panels 16a and 16b.

  The buckling load absorbing panels 16a and 16b absorb the increased pressure inside the packaging container. When the pressure is increased, the buckling load absorbing panels 16a and 16b are pressed outward from the plastic bottle. Thus, the buckling load absorbing panels 16a and 16b absorb a part of the buckling load applied to the plastic bottle, and thereby the container wall is pressed inward when the packaging container is opened, and the liquid is absorbed. The problem that the contents are pushed out from the mouth and spills is also eliminated.

  Further, the plastic bottle is provided with a lateral rib 19 on the shoulder portion 9 and lateral ribs 20, 21, 22 on the upper flat wall portion 12a and the lower flat wall portion 12b. These lateral ribs 19 to 22 absorb part of the buckling load and prevent buckling deformation.

  In the present invention, as shown in FIG. 4, the groove depth d2 of the longitudinal groove 15 is larger than the groove d1 of the circumferential groove 14, and the groove depth d2 / the groove of the circumferential groove 14 The ratio of the depth d1 is preferably 1 to 1.5. When the ratio of the depth d2 of the longitudinal groove 15 to the depth d1 of the circumferential groove 14 is less than 1, the plastic bottle is deformed when subjected to a vertical load, which is not desirable. On the other hand, when the ratio of the groove depth d2 of the longitudinal groove 15 / the groove depth d1 of the circumferential groove 14 is larger than 1.5, the formability (ease of swelling of the bottle) at the time of blow molding is poor. Is undesirable.

  In the present invention, the weight per unit volume of the plastic bottle can be 0.036 g / ml to 0.048 g / ml. This lightweight plastic bottle can be manufactured using, for example, the preform shown in FIG.

  A preform 1 for producing a plastic bottle having a resin weight of 20.5 g shown in FIG. 8 is a plastic bottle molding provided with a cap portion 2, a support ring 3, a body portion 5, and a bottom portion 6 that closes an end portion of the body portion 5. Preform, for which the resin weight is 20.5 g, the support ring 3 is provided with a support ring lower thin part 4 having a length of 7 to 8 mm which is the minimum thin part, and the bottom part 6 is directed to the gate part. The wall thickness is gradually made thinner.

The support ring lower thin portion 4 is preferably formed to have a length of 7 to 8 mm, and particularly preferably 7.5 mm. When the length of the support ring lower thin part 4 is smaller than 7 mm, sufficient stretchability of the support ring lower thin part 4 is not obtained, and the maximum thickness part of the preform is easily stretched, and the thin bottle body A part will be formed. On the other hand, when the length of the support ring lower thin part 4 is larger than 8 mm, the bottle shoulder becomes thin, and particularly when the length of the support ring lower thin part 4 is 10 mm, the bottle shoulder becomes too thin.
The thickness of the gate portion below the bottom portion 6 is 2.35 mm, which is thinner than the 2.5 mm thickness of the gate portion in a commonly used 500 ml plastic bottle molding preform.

  The total length of the preform 1 is preferably 85.0 mm and the body diameter is preferably 22.2 mm. Thereby, when the longitudinal dimension of the bottle to be molded is 176 mm, the longitudinal length of the cap portion is 21.01 mm, and the lateral width of the bottle is 61 mm, the longitudinal stretching ratio: (176-21.01) ) / (85-21.01) = 154.99 / 63.99 = 2.42, transverse direction stretch ratio: 61 / 22.2 = 2.75, and the stretch ratio during blow molding can be increased. .

  In the preform 1, the thickness of the body portion 5 is set to 3.0 mm or less, the support ring lower thin portion 4 is formed to a thickness of 2.1 mm and a length of 7.5 mm, and the gate portion thickness is set to 2.35 mm. It is desirable.

  The preform 1 shown in FIG. 8 shows an example of a preform for molding a 500 ml plastic bottle having a total length of 85 mm. In FIG. 8, 1a indicates the length of the lower support ring thin portion 4 = 7.5 mm, 1b indicates the thickness of the lower support ring thin portion 4 = 2.1 mm, and 1c is extracted from below the support ring. The length to the taper start position = 14.4 mm, and 1d represents the thickness of the body = 3.2 mm. 1e is the total length of the preform 1 = 85.0 mm, 1f is the body diameter of the preform 100 = 22.2 mm, and 1 g is the gate portion thickness = 2.5 mm. 1h indicates the length from the tip of the preform to the bottom of the support ring 3 = 21.01 mm.

  For reference, the shape of a conventional preform 100 is shown in FIG. A preform 100 shown in FIG. 9 is a plastic bottle molding preform including a spout 112, a support ring 113, a body 115, and a bottom 116 that closes an end of the body 115. In FIG. 8, 2a indicates the length of the thin part of the lower support ring = 3.0 mm, and the length of the thin part of the lower support ring in the preform 1 for producing a plastic bottle of 20.5 g shown in FIG. It is shorter than 5mm. 2b shows the thickness of the thin part under the support ring = 2.1 mm. 2c indicates the length from the bottom of the support ring to the start of the taper taper = 14.4 mm, and 2d indicates the thickness of the body = 3.2 mm. 2e indicates the total length of the preform = 92.5 mm. This is shorter than the total length of the preform 1: 85 mm. 2f shows the body diameter of the preform = 24.0 mm. This is larger than the body diameter: 22.2 mm of the preform 1 for producing a 20.5 g plastic bottle shown in FIG. 2g shows gate part thickness = 2.5mm. 2h indicates the length from the tip of the preform to the bottom of the support ring = 21.01 mm.

  In the preform 1 for manufacturing 20.5g plastic bottles, the length of the support ring lower thin part 4 is 7-8mm, and the thickness is gradually reduced with the bottom 4 facing the gate part. The stretchability of the thin part 4 under the ring can be improved, the thickness of the bottle body can be increased, and the physical properties of the bottle can be improved. By setting it to ˜8 mm, the wall thickness of the shoulder portion of the bottle can be kept within a range not affecting the physical properties of the bottle.

  Examples of the thermoplastic resin constituting the preform 1 for forming plastic bottles include thermoplastic polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyarylate, and copolymers thereof, these resins or others. Blends with these resins are preferred, and ethylene terephthalate-based thermoplastic polyesters such as polyethylene terephthalate can be suitably used. In addition, tolyl resin, polypropylene, propylene-ethylene copolymer and the like can be used for acrylo. Various additives such as a colorant, an ultraviolet absorber, a release agent, a lubricant, a nucleating agent, an antioxidant, an antistatic agent and the like are blended with the above-described resin within a range that does not impair the quality of the molded product. be able to.

  As the ethylene terephthalate thermoplastic resin constituting the preform 1, an ethylene terephthalate unit occupies most of the ester repeating portion, generally 70 mol% or more, and has a glass transition point (Tg) of 50 to 90 ° C. Those having a melting point (Tm) in the range of 200 to 275 ° C. are preferred. In addition, as an ethylene terephthalate thermoplastic polyester, polyethylene terephthalate is particularly excellent in terms of pressure resistance, but in addition to the ethylene terephthalate unit, an ester composed of a dibasic acid such as isophthalic acid or naphthalenedicarboxylic acid and a diol such as propylene glycol. Copolyesters containing a small amount of units can also be used.

  The preform 1 can also be composed of two or more thermoplastic polyester layers. Furthermore, when the preform 1 is composed of two or more thermoplastic polyester layers, an intermediate layer such as a barrier layer or an oxygen absorbing layer can be provided between the layers. As the oxygen absorbing layer, a combination of an oxidizable organic component and a transition metal catalyst, or a layer containing a gas barrier resin that does not substantially oxidize can be used.

Next, a process for forming a plastic bottle using the preform 1 of the present invention will be described.
First, the preform 1 of the present invention is set in a mold heated to 140 to 150 ° C., and the preform 1 is blown air from the blow port into the preform while being stretched upward by a stretching rod. Thereafter, it is held for several seconds to heat-set with a mold, air is blown into the molded product to cool it, and at the same time, it is exhausted from the blow port. The mold is then opened and the product is removed.
Next, the present invention will be described with reference to examples and comparative examples.

A preform having the following dimensions was manufactured in the shape shown in FIG. 8 by injection molding of polyethylene terephthalate.
Total length 85mm
Body diameter 22.2mm
Support ring bottom thin section 7.5mm
Thickness of thin part under support ring 2.1mm
Length from under support ring to taper start position 14.4mm
Body thickness 3.2mm
Gate thickness 2.5mm
Preform weight 20.5g

The above preform is preheated, blow-molded by a known biaxial stretch blow molding machine, has the shape shown in FIG. 1, and the ratio of the depth of the longitudinal groove / the depth of the circumferential groove Was molded into a 1.2 plastic bottle.
The vertical buckling strength of the obtained plastic bottle was measured.

  About this plastic bottle, the buckling strength of the plastic bottle was measured using the AGR top load tester (buckling test machine). As shown in FIG. 10, the plastic bottle 7 is arranged on the support base 24, the detection head 23 is moved downward at a load speed of 0.8 mm / sec, a load displacement of 20 mm, and the plastic bottle 7 is compressed. The buckling strength was examined. As a result, as shown by a curve a in FIG. 11, it was found that the plastic bottle has a high buckling strength of 25 to 30 g / f or more, which is required when palletizing plastic bottles, packing them in stages, and transporting them. .

  In addition, the plastic bottles were horizontally stacked and examined for the occurrence of deformation or crushing. As a result, it was found that there was no deformation, crushing, etc., and it had sufficient vendor suitability.

"Comparative Example 1"
In the same manner as in Example 1, except that a plastic bottle having a ratio of the depth of the longitudinal groove / the depth of the circumferential groove of 0.8 was molded, and the vertical buckling strength was measured in the same manner as in Example 1. Went. As a result, as shown by the curve b in FIG. 11, the buckling strength is lower than that of Example 1, and 25-30 g / f required when plastic bottles are packed in pallets, packed in stages, and transported. It was found that it had only the following low buckling strength.

  The packaging container of the present invention has vendor suitability and can be lighter than conventional 500 ml plastic bottles, and can be used as a lightweight packaging container suitable for sale by a vending machine. .

It is a side view of the plastic bottle of this invention. FIG. 2 is an end view taken along line AA shown in FIG. 1. It is an end view cut and shown by the BB line shown in FIG. FIG. 2 is an end view cut along the line CC shown in FIG. 1. It is sectional drawing cut | disconnected and shown by the DD line | wire shown in FIG. It is a perspective view which shows the corner part of the plastic bottle of this invention. It is an end view of the buckling absorption panel 17a. It is a partial cross section illustration side view of preform 1 for plastic bottle manufacture whose resin weight is 20.5g. It is a partial cross section illustration side view of the conventional preform. It is a perspective view which shows the measurement state of buckling strength by a buckling test machine. It is a graph which shows the measurement result of the vertical buckling strength about Example 1 and Comparative Example 1.

Explanation of symbols

7 Plastic bottle 8 Portion part 8a Support ring 9 Shoulder part 10 Body part 11 Bottom part 12 Flat wall part 12a Upper flat wall part 12b Lower flat wall part 13 Corner part 14 Circumferential groove 15 Vertical groove 16a Buckling load absorption panel 16b Seat Bending load absorbing panel 17 Arc-shaped curved part 18 Rib 19 Lateral rib 20 Lateral rib 21 Lateral rib 22 Lateral rib d1 Depth of circumferential groove 14 d2 Depth of groove of longitudinal groove 15 Detection head 24 Support base a First embodiment Curve showing measurement result of buckling strength of curve b Curve showing measurement result of buckling strength of Comparative Example 1 1 Preform for producing plastic bottle with resin weight of 20.5 g 2 Mouth part 3 Support ring 4 Under support ring Thin part 5 Body part 6 Bottom part 1a Support ring bottom thin part 1b Support ring bottom thin part thickness 1c Pull out from under support ring taper Length to start position 1d Body thickness 1e Total length of preform 1 1f Body diameter 1g Gate thickness 1h Length from preform tip to under support ring 100 Conventional preform 112 Mouth plug 113 Support Ring 114 Support ring lower thin part 115 Trunk part 116 Bottom part 2a Support ring lower thin part 2b Thickness of support ring lower thin part 2c Length from bottom of support ring to extraction taper start position 2d Body thickness 2e Total length of reform 2f Conventional preform body diameter 2g Gate thickness 2h Length from the tip of the preform to the bottom of the support ring

Claims (4)

  It has a spout, a support ring, a shoulder, a body, and a bottom, and the body is composed of four flat walls and a corner connecting the flat walls, and an annular circumferential groove that crosses the flat wall and the corner. A plastic bottle in which the flat wall portion is divided into an upper flat wall portion and a lower flat wall portion by a circumferential groove, wherein a longitudinal groove is engraved in a corner region near the circumferential groove. Plastic bottle.   The upper flat wall part is formed in an isosceles trapezoid, the lower flat part is formed in an inverted isosceles trapezoid, and the corner area corresponding to the short side of the upper flat wall part and the lower flat wall part is an arcuate curved part. The plastic bottle according to claim 1, wherein the plastic bottle is formed.   3. The plastic bottle according to claim 1, wherein the plastic weight of the plastic bottle is 0.036 g / ml to 0.048 g / ml. The plastic bottle according to any one of claims 1 to 3, wherein the ratio of the depth of the longitudinal groove / the depth of the circumferential groove is 1 to 1.5.

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