JPH0676012U - Aseptic filling plastic bottle - Google Patents

Abstract

(57) [Summary] (Corrected) [Purpose] When the sterilizing solution is discharged after bottle sterilization, the residual liquid amount is small, and as a result, cleaning can be performed efficiently, and the sterilizing liquid discharge time and the sterilization process as a whole. Save time and improve productivity. A bead is provided with a lower taper portion 11 having a large inclination angle with respect to a horizontal plane and an upper taper portion 12 having an opposite inclination with a small inclination angle, and the most recessed portion 13 is a bead which is biased upward and the bead of the side wall upper portion 6 is formed. Aseptic filling plastic bottle having a depth smaller than the bead depth of the lower side wall 7.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a plastic bottle for aseptic filling, and more specifically, the residual liquid amount is small when the sterilizing liquid is discharged after the sterilization of the bottle, and as a result, the cleaning can be performed efficiently and the discharging time of the sterilizing liquid can be improved. And a plastic bottle for aseptic filling capable of shortening the sterilization time as a whole and improving productivity.

[0002]

[Prior art]

 Conventionally, aseptic filling packaging technology has been known as a packaging technology for retaining the flavor of liquid contents. This technique generally sterilizes liquid contents for a short period of time at high to ultra high temperatures and then rapidly cools them, and then sterilizes packaging materials such as bottles with a sterilizing solution. It is filled and sealed. As the sterilizing liquid used for sterilizing the packaging material, one containing peracetic acid and / or hydrogen peroxide is used. Fill the container with the sterilizing liquid until it overflows, then invert and discharge the sterilizing liquid. And then washed with sterile wash water.

This aseptic filling technique has an advantage that it can be widely applied to containers having poor heat resistance such as plastic bottles. Plastic bottles are formed by blow molding or stretch blow molding of plastic.However, in order to reduce the weight of the plastic and give it the required strength, it is necessary to provide circumferential beads on the side wall in multiple stages. It is used.

[0004]

[Problems to be solved by the device]

 It was found that there is still a problem to be solved when applying the above-mentioned aseptic filling technique to a plastic bottle with a multi-stage bead in the circumferential direction. That is, when the used sterilizing solution and washing water are discharged in an inverted state from the plastic bottle with multi-stage beads, the sterilizing solution and washing water flow down while being entangled with the beads in each stage, so the sterilizing solution and washing water are discharged from the bottle. It takes a long time to do so, and in the end, the washing water after washing adheres to and remains on the beads at each stage, and the amount of residual liquid increases, which is a drawback. As an example, in the case of a 2-liter plastic bottle with multi-stage beads, the residual amount of sterilizing solution reaches 3 to 5 g even after 8 seconds, and the residual amount of washing water after washing is 3 to 7 g even after 5 seconds. is there.

The large amount of the residual liquid of the sterilizing liquid and the washing water as described above means that it takes a long time to discharge the liquid in order to reduce the residual liquid amount, and the cleaning after the sterilization has a heavy load. It means that it takes a burden. Thus, regarding the sterilization treatment of aseptic filling plastic bottles, in terms of productivity as well as saving of sterilizing liquid and washing water, it is possible to discharge the liquid in an inverted state, and a plastic with a small residual liquid amount. A bottle is desired.

Therefore, the object of the present invention is to eliminate the above-mentioned drawbacks in the conventional plastic bottle with a multi-stage bead, and to increase the discharging speed of the sterilizing solution and the washing water in the inverted state after the bottle sterilization. As a result, the amount of residual liquid can be reduced, and as a result, aseptic filling that can improve the efficiency of cleaning, shorten the discharge time of sterilizing liquid and cleaning water and the overall sterilization treatment time, and improve productivity To provide plastic bottles for.

According to the present invention, in a plastic bottle formed by plastic blow molding or stretch blow molding and having circumferential beads on the side wall in multiple stages, the bead has a large inclination angle with respect to the horizontal plane. The bead has a side taper portion and an upper taper portion in the opposite direction with a small inclination angle, and the most concave portion is biased upward, and the bead depth at the upper side wall is smaller than the bead depth at the lower side wall. A plastic bottle for aseptic filling characterized by the above is provided.

In the plastic bottle of the present invention, the inclination angle (α) of the lower taper portion is in the range of 60 to 80 degrees, especially 60 to 70 degrees, while the inclination angle (β) of the upper taper portion is 15 to 15 degrees. It is preferably in the range of 55 degrees, especially 40 to 50 degrees.

The depth of the bead on the upper portion of the side wall is preferably ½ to ⅔ of the depth of the bead on the lower portion of the side wall, particularly ⅔ to ⅔.

INDUSTRIAL APPLICABILITY The present invention can be applied to various plastic bottles, in which the plastic is formed of a thermoplastic polyester mainly composed of ethylene terephthalate units and at least the side wall portion is biaxially molecularly oriented by stretch blow molding. It is especially useful for existing bottles.

[0011]

[Action]

 In FIG. 1 for explaining a bead in a multi-stage beaded plastic bottle of the present invention, A indicates a bead in an upright state, B indicates an bead in an inverted state, and this bead 10 has a large inclination angle with respect to a horizontal plane (inclination). It is provided with a lower taper portion 11 (of an angle α) and an opposite upper taper portion 12 of a small inclination angle (inclination angle β). This bead 10 has a deepest recess 13 having a depth d, but this deepest recess 13 is biased upward.

Further, in FIG. 2 showing the bead on the lower side wall and the bead on the upper side wall in comparison, the depth d ₁ of the bead 10a on the upper side wall is smaller than the depth d ₂ of the bead 10b on the lower side wall. To do.

According to the present invention, a multi-stage bead having the above-described shape and size is formed on the side wall of a bottle, thereby increasing the discharge rate of the sterilizing solution or washing water in an inverted state after bottle sterilization. At the same time, the amount of residual liquid can be reduced.

Please refer to Examples and Comparative Examples described later. That is, in the case of a plastic bottle with a multi-stage bead in which the bead provided on the side wall has a vertically symmetrical inclination, the residual amount of the sterilizing liquid after the sterilizing liquid overflow treatment for 3 minutes and holding for 8 seconds was greater than 3 g. Yes, the remaining amount of water after washing reaches about 3 to 7 g even after washing for 3 seconds and holding for 5 seconds in an inverted state. In order to make the residual water amount after cleaning on the order of 1 g, it is necessary to hold the inverted state for 11 seconds.

On the other hand, according to the present invention, in the case of a plastic bottle with a multi-stage bead in which a bead provided on a side wall has a specific asymmetrical inclination in the vertical direction, a sterilizing solution is subjected to overflow treatment for 3 minutes and sterilization after holding for 8 seconds. The residual liquid amount of the liquid is almost less than 2 g, and it is possible to reduce the residual water amount after cleaning when the liquid is washed for 3 seconds and held for 5 seconds in an inverted state to the order of 1 g. .

In the multi-stage bead-equipped plastic bottle of the present invention, the reason why the bead inclination is as described above can accelerate the liquid discharging speed and reduce the residual liquid amount. The large lower taper portion 11 is on the upper side, and the liquid whose flow velocity is increased by the taper portion 11 located on the upper side is caused to flow down together with the liquid on the taper portion 12 located on the lower side, so that the liquid is satisfactorily drained. It seems to be because. This is truly another finding. That is, according to the conventional wisdom, it is predicted that if there is a portion with a small inclination on the lower side, the liquid will easily accumulate in this portion, but the fact is that the upper inclination angle is large and the lower inclination angle is large. By making the value small, the drainage from the bead improved.

In the present invention, since the sterilizing liquid and the cleaning water are likely to adhere to the upper bead, it is also important to set the depth of the bead on the upper side wall to be smaller than the depth of the bead on the lower side wall. The bead depth is related to both the strength of the container and the residual liquid amount. In the present invention, by increasing the depth of the bead at the lower part of the side wall, a sufficient lateral rigidity and axial load strength reinforcement effect is given to the lower part of the side wall, which is important for the strength of the container, and the bead depth at the upper part of the side wall is increased. By making the depth shallow, it is possible to reduce the amount of residual liquid by improving the drainage of the lower part when draining liquid in an inverted state.

In the present invention, forming the multi-stage bead with the lower taper portion having a large inclination angle and the upper taper portion having an opposite inclination having a small inclination angle brings an additional advantage. One of the drawbacks of the plastic container with multi-stage beads is that dust tends to be deposited on the upward slope of the bead, but in the present invention, this tendency is mitigated by increasing the slope of the upward slope of the bead. To be done.

In the plastic bottle of the present invention, the inclination angle (α) of the lower taper portion is preferably in the range of 60 to 80 degrees, particularly in the range of 60 to 70 degrees. When the liquid is drained, the liquid runs out worse, and the amount of residual liquid tends to increase. On the other hand, if it is larger than the above range, the bead becomes too shallow and a satisfactory reinforcing effect cannot be obtained. On the other hand, the inclination angle (β) of the upper taper portion is preferably in the range of 15 to 55 degrees, particularly 40 to 50 degrees. When it is smaller than the above range, the liquid runs out during draining in the inverted state. However, the residual liquid amount also tends to increase. On the other hand, if it is larger than the above range, the number of beads per unit height decreases, and it becomes impossible to obtain a satisfactory reinforcing effect.

The depth of the bead on the upper side wall is preferably ½ to ⅔ of the depth of the bead on the lower side wall, especially ⅔ to ⅔. If it is smaller than the above range, the bead becomes too shallow, and a satisfactory reinforcing effect cannot be obtained.On the other hand, if it is larger than the above range, the liquid will run out during draining in an inverted state, and the residual liquid amount will also increase. Tends to increase.

[0021]

[Preferred mode of the invention]

 (Shape and Structure of Bottle) In FIG. 3 (front view), FIG. 4 (side view) and FIG. 5 (top view) showing an example of the structure of the plastic bottle of the present invention, the container 1 of this concrete example is made of a thermoplastic material. It is formed by biaxial stretch blow molding of polyester, and has a mouth portion (nozzle portion) 2, a trapezoidal shoulder portion 3, a tubular body portion 4 and a closed bottom portion 5. Reinforcing ribs 9 are provided in a fan shape on the trapezoidal shoulder portion 3.

On the entire surface of the tubular body 4, circumferential beads 10 are formed in multiple stages, and these beads 10 have a lower taper portion 11 having a large inclination angle (at an inclination angle α) with respect to a horizontal plane. And an upper taper portion 12 having a small inclination angle (inclination angle β) in the opposite direction. This bead 10 has a deepest recess 13 of depth d, but this deepest recess 13 is biased upward. In FIG. 14 (front view) and FIG. 15 (side view) showing a conventional bottle with a multi-stage bead for comparison, circumferential beads 10 are formed in multiple stages, and in these beads 10, the lower tapered portion 11 is formed. However, the inclination angle is the same in the upper taper portion 12, and the shape of the bead is vertically symmetrical.

In the multi-tiered bead 10 on the side wall of the body, the bead size is different between the upper side wall 6 and the lower side wall 7, and the depth d ₁ of the bead 10a on the upper side wall is shallow, and the depth of the bead 10b on the lower side wall is deep. The depth d ₂ is deep. In this specific example, a bead 10c having the largest depth is provided between the upper side wall 6 and the lower side wall 7 for the purpose of reinforcement.

In the present invention, the size (depth) of the bead provided on the side wall may be constant over the entire circumference within a range satisfying the above-mentioned conditions, or may change in a part of the circumference. May be. For example, in a bottle with a rectangular cross section, the bead on the long side is deepened (Fig. 3) and the bead on the short side is shallowed (Fig. 4), which requires a stronger degree of reinforcement, as shown in Figs. 3 and 4. be able to. It is also possible to increase the bead at the corners of the bottle where reinforcement is required.

The bead depth at the lower portion of the side wall varies depending on the volume and basis weight of the bottle, but generally speaking, the bead depth is in the range of 1 to 4 mm, and particularly 2 to 3 mm, because of the reinforcing effect and liquid drainage. In consideration of the balance, the distance between the beads is preferably 13 to 25 mm, particularly 18 to 20 mm.

The bead most recessed portion 13 is preferably formed on a smooth concave surface, and the lower tapered portion 11 and the upper tapered portion 12 are tangentially connected to this concave surface. The radius of curvature (R) of the concave surface can generally be in the range 0.5 to 6 mm, especially 2 to 4 mm. A small curvature portion can be provided between the lower taper portion 11 and the upper taper portion 12 and the tubular body portion 4, and the radius of curvature of this curvature portion is 2 to 10 mm, particularly 3 to 5 mm. Good to have. The lower taper portion 11 and the upper taper portion 12 are generally linear in a bottle axial direction cross section, but of course the cross section may be a curve such as a circle, an ellipse, a parabola, or a hyperbola. Good. In the case of these curves, the inclination angle is the inclination angle of the line connecting the connecting portion of the tubular body and the connecting portion of the most recessed portion for each taper portion.

The cross section of the bottle body may have any shape such as a square with rounded corners, a rectangle with rounded corners, a circle, an ellipse, and a hexagon. Figures 3, 4 and 5 are rectangles with rounded corners, and Figures 6, 7 and 8 are other examples of the same type, Figure 9 (front view) and Figure 10 (top view). The one shown in the figure) is an example of a square with rounded corners.

In the bottle of the present invention, the beads are provided in multiple stages, but these beads may be provided on the entire circumference of the side wall or a part of the entire circumference. 11 (front view), FIG. 12 (side view), and FIG. 13 (top view) showing still another example of the structure of the plastic bottle of the present invention, the container 1 of this specific example is a biaxial thermoplastic polyester. It is formed by stretch blow molding and consists of a mouth part (nozzle part) 2, a trapezoidal shoulder part 3, a cylindrical body part 4 and a closed bottom part 5, and the cross section of the bottle body part is The rectangular shape with rounded corners is common to that shown in FIGS. 3, 4 and 5, but as shown in FIG. A shallow bead 10a and a deep bead 10b at the bottom of the side wall are provided. On the other hand, as shown in FIG. 8, an inner long side of the side wall is provided with a panel portion or a design portion 14 at the center for alleviating an internal volume change. Provide the beads 10a, 10b in multiple stages only on both ends It can be.

(Manufacture of Bottle) In the present invention, any plastic can be used as the plastic constituting the bottle as long as it is a thermoformable thermoplastic resin material, for example, low-, medium-, and high-plastic. Olefin resins such as density polyethylene, isotactic polypropylene, crystalline propylene-ethylene copolymer, crystalline ethylene-butene copolymer, crystalline ethylene-propylene-butene copolymer or blends thereof; styrene Resins; vinyl chloride resins; vinylidene chloride resins; thermoplastic polyester resins; polyamide resins such as nylon 6, nylon 66, copolymerized nylons thereof, etc .; high nitrile resins and the like can be used alone or in combination of two or more kinds.

These resins can be appropriately selected and used according to the molding method. For example, polyethylene and the like are suitable for the direct blow molding method, and polyester resin, high nitrile resin and the like are stretch-blown. Suitable for molding method. Polypropylene can be applied to both the direct blow molding method and the stretch blow molding method.

These resins can be used alone, but when high content storage stability is required, they can be used in combination with an oxygen gas barrier resin in the form of a laminate. As the oxygen barrier resin, a resin having an oxygen permeability coefficient of 5.5 × 10 ¹² cc · cm / cm ² · s ec · cm Hg or less (37 ° C., 0% RH), for example, ethylene-vinyl alcohol copolymer Coal, polyamide resin, vinylidene chloride resin, high nitrile resin, etc. are used.

The plastic used in the present invention may be mixed with a known compounding agent for plastics, such as an antioxidant, a heat stabilizer, an ultraviolet absorber, an antistatic agent, a filler, a colorant and the like. it can. To make the molding container opaque, fillers such as calcium carbonate, calcium silicate, alumina, silica, various clays, gypsum, talc, magnesia, titanium white, yellow iron oxide, red iron oxide, ultramarine, chromium oxide. Inorganic pigments such as and organic pigments can be blended.

The bottle of the present invention is preferably formed of ethylene terephthalate thermoplastic polyester in order to reduce the weight of the container and to perform aseptic filling with high productivity. The ethylene terephthalate type thermoplastic polyester occupies most of the ester repeating units, generally 60 mol% or more, and particularly 80 mol% or more, and has a glass transition point (Tg) of 50 to 90 ° C., Particularly, a thermoplastic polyester having a melting point (Tm) of 220 to 260 ° C., particularly 240 to 260 ° C. at 70 to 90 ° C. is suitable. Homopolyethylene terephthalate is preferred in terms of mechanical properties, but copolymerized polyesters containing small amounts of ester units other than ethylene terephthalate units can also be used.

Dibasic acids other than terephthalic acid include aromatic dicarboxylic acids such as isophthalic acid, phthalic acid, and naphthalene dicarboxylic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; succinic acid, adipic acid, sebacic acid, dodecane. Examples of the diol component other than ethylene glycol include propylene glycol, 1,4-butanediol, diethylene glycol, and 1,6-hexylene glycol. , Cyclohexanedimethanol, an ethylene oxide adduct of bisphenol A, and the like, or two or more thereof.

The ethylene terephthalate-based thermoplastic polyester used should have at least a molecular weight sufficient to form a film, and an injection grade or an extrusion grade is used depending on the application. Its intrinsic viscosity (IV) is generally in the range of 0.4 to 1.5 dl / g, preferably 0.5 to 1.5 dl / g.

The plastic bottle of the present invention can be manufactured by a blow molding or stretch blow molding method known per se except that a blow mold corresponding to the above container shape is used. In blow molding (direct blow molding), the extruded molten parison is pinched off with a mold, and a fluid is blown into the parison for blow molding. In the present invention, the stretch blow molding method is preferable. In this case, the plastic is melt-molded into an amorphous bottomed preform having a mouth portion and a bottom portion, and the preform is stretched in the axial direction and the circumferential direction. If necessary, the stretch-molded part is heat-set. Molding into a preform can be performed by injection molding or extrusion molding.

For stretch molding from the preform, a method of manufacturing a preform in a supercooled state and then heating the preform to a stretching temperature to perform stretch molding, or heat applied to the preform to be molded is used. That is, a method of utilizing the residual heat to perform preforming followed by stretching is adopted.

The stretching temperature is appropriately in the range of 80 to 200 ° C., particularly 90 to 120 ° C. The preform or parison at the stretching temperature is stretched and stretched in the blow mold in the axial direction and expanded and stretched in the circumferential direction by blowing a fluid. Regarding the draw ratio, the axial draw ratio is 1.0 to 5.0 times, particularly 1.5 to 4.0 times, and the circumferential draw ratio is 2.0 to 6.0 times, and particularly 2.5 to 5. It is good to make it 5 times.

(Sterilization and Washing of Bottles) In the production of aseptic filling bottling products, the bottle of the present invention is sterilized in the bottle sterilization step, then washed with water and sent to the aseptic filling / sealing step. The sterilizing solution used contains peracetic acid and / or hydrogen peroxide, and a suitable sterilizing solution composition is 0.5% peracetic acid (CH ₃ COOO H) and / or hydrogen peroxide (H ₂ O). It is contained at a concentration of 5% to 5%. Also, high-concentration ozone water can be used as the sterilizing liquid.

In the bottle sterilization step, first, the bottle is placed in an upright state, and a sterilizing solution is poured into the bottle to make it overflow. This holding time is generally in the order of 60 to 180 seconds, although it depends on the inner volume of the container. Then invert the bottle and allow the germicidal solution to drain. In the bottle of the present invention, it is an advantage that the sterilizing solution can be discharged within a short time by reducing the residual liquid amount. The holding time for discharging the sterilizing solution varies depending on the inner volume of the container, but is generally on the order of 5 to 15 seconds. Then, the bottle is turned upside down and sprayed with washing water to wash and drain the washing water. The holding time for this purpose is generally on the order of 3 to 7 seconds, although it depends on the internal volume of the container. The bottle after washing can be blown with sterile air to accelerate the drainage.

In the aseptic filling / sealing process, the contents are previously supplied to a heat exchanger (UHT device), sterilized at an ultrahigh temperature for an extremely short time, and then rapidly cooled and sent to the aseptic filling / sealing process. The aseptic filling / sealing process is maintained in an aseptic environment, and a sterilized and washed bottle is filled with sterilized contents from the UHT device, and then a sterilized and washed cap is capped and sealed.

[0042]

【Example】

 The invention will be further described in the following examples. Example 1 A polyethylene terephthalate (PET) having an intrinsic viscosity (IV) of 0.75 dl / g was molded by an injection molding machine at an injection temperature of 290 ° C. to form a preform (diameter 28 mm, weight 63 g). This preform was reheated to 115 ° C., conveyed into a mold of a blow molding machine, stretched in the axial direction by a stretch rod and immediately blown with high pressure air to mold a bottle having a shape shown in FIGS. 3 to 5 (contents). 2050m1 product, average wall thickness 0.4mm).

The dimensions of each part are as follows. Height of container 305mm, height of side wall lower part 150mm, height of side wall upper part 95mm, length of long side part of body part 105.5mm, depth of side wall lower bead most concave part of long side part 2.5mm, bottom Inclination angle of side taper part 63 degrees, inclination angle of top taper part 45 degrees, spacing between beads 10.5 mm, depth of side wall upper bead most concave part of long side part 2.0 mm, inclination angle of bottom taper part 63 Degree, inclination angle of upper taper part 45 degrees, interval between beads 11 mm, length of short side part of body part 87 mm, depth of side wall lower bead most concave part of short side part 2.0 mm, inclination of lower taper part Angle 68 degrees, inclination angle of upper taper portion 50 degrees, distance between beads 10.5 mm, depth of side wall upper bead most concave portion of short side portion 1.5 mm, inclination angle of lower taper portion 68 degrees, upper taper portion Inclination of 50 degrees, between beads Interval 11mm.

This bottle was held in an upright state in a sterilizer, and 4% hydrogen peroxide solution as a sterilizing solution was allowed to flow down, and the bottle was kept in an overflow state for 3 minutes. After that, the bottle was inverted and the sterilizing liquid was discharged for 8 seconds, and then sterile water was sprayed for 3 seconds for washing in this state. After washing, this state was maintained for 3 seconds and the washing water was discharged. The residual liquid amount of the sterilizing liquid after discharging the sterilizing liquid and the residual water amount of the cleaning water after discharging the cleaning water were measured for 10 samples, and the results are shown in Table 1.

[0045]

[Table 1] In the above table, X is the average value, S is the standard deviation, Max is the maximum value, Min is the minimum value, and R is the deviation.

Comparative Example 1 In Example 1, with the multi-stage bead having vertically symmetrical taper portions shown in FIGS. 14 and 15, in the same manner as in Example 1 except that the size of each bead was changed as follows. An aseptic filling plastic bottle was manufactured.

The bead at the bottom of the side wall lower bead of the long side is 2.5 mm, the inclination angle of the lower taper portion is 45 degrees, the inclination angle of the upper taper portion is 45 degrees, the spacing between the beads is 13 mm, and the side wall upper portion of the long side portion is Depth of bead most recessed part 2 mm, inclination angle of lower tapered part 53 °, inclination angle of upper tapered part 53 °, spacing between beads 13 mm, short side wall lower bead most recessed part depth 2.5 mm, lower Side taper inclination angle of 45 degrees, upper taper inclination angle of 45 degrees, bead spacing 13 mm, side wall upper bead most recessed part depth of short side 2 mm, lower taper inclination angle 53 degrees, upper taper The inclination angle of the part is 53 degrees, and the interval between the beads is 13 mm.

Table 2 shows the results of the same sterilization and washing test as in Example 1 for this bottle. The holding time for discharging after cleaning was changed as shown in Table 2.

[0049]

[Table 2]

Example 2 A plastic bottle for aseptic filling with a multi-stage bead was produced in the same manner as in Example 1 except that the diameter of the bottle was changed to 38 mm. Table 3 shows the results of the sterilization and washing tests as in Example 1 performed on this bottle.

[0051]

[Table 3]

[0052]

[Effect of device]

 According to the present invention, in a plastic bottle in which a circumferential bead is formed in multiple stages on the side wall, this bead is provided with a lower taper portion having a large inclination angle with respect to a horizontal plane and an upper taper portion having a small inclination angle in the opposite direction. By providing a bead having the uppermost concave portion and an uppermost concave portion, the lower taper portion having a large inclination angle becomes the upper side in the inverted state, and the taper portion located at the upper side allows the liquid having the increased flow velocity to be formed. , The liquid in the taper portion located on the lower side can be caused to flow down along with it, and the liquid can be satisfactorily drained.

In the present invention, the bead on the lower part of the side wall is deepened to provide a sufficient reinforcing effect to the lower part of the side wall, which is important for the strength of the container, and the bead on the upper part of the side wall is made shallow. As a result, when the liquid is drained in the inverted state, it is possible to reduce the amount of residual liquid by making the lower part of the liquid drain well.

In the present invention, forming a multi-step bead with a lower taper portion having a large inclination angle and an opposite upper taper portion having a small inclination angle brings an additional advantage. One of the drawbacks of the plastic container with multi-stage beads is that dust tends to be deposited on the upward slope of the bead, but in the present invention, this tendency is mitigated by increasing the slope of the upward slope of the bead. To be done.

[Brief description of drawings]

FIG. 1 is an enlarged explanatory view for explaining a bead in a plastic bottle with a multi-stage bead according to the present invention, in which A is an upright bead and B is an inverted bead.

FIG. 2 is an enlarged explanatory view showing a bead on the lower side wall and a bead on the upper side wall of the multi-stage bead-equipped plastic bottle of the present invention in comparison.

FIG. 3 is a front view showing an example of the structure of the plastic bottle of the present invention.

FIG. 4 is a side view of the bottle of “FIG. 1”.

FIG. 5 is a top view of the bottle of “FIG. 1”.

FIG. 6 is a front view showing another example of the structure of the plastic bottle of the present invention.

FIG. 7 is a side view of the bottle of “FIG. 6”.

FIG. 8 is a top view of the bottle of “FIG. 6”.

FIG. 9 is a front view showing still another example of the structure of the plastic bottle of the present invention.

FIG. 10 is a top view of the bottle of “FIG. 9”.

FIG. 11 is a front view showing still another example of the structure of the plastic bottle of the present invention.

FIG. 12 is a side view of the bottle of “FIG. 11”.

FIG. 13 is a top view of the bottle of “FIG. 11”.

FIG. 14 is a front view showing a conventional bottle with multi-stage beads for comparison.

FIG. 15 is a side view of the bottle of “FIG. 14”.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container (bottle) 2 Mouth part (nozzle part) 3 Trapezoidal shoulder part 4 Cylindrical body part 5 Closed bottom part 6 Side wall upper part 7 Side wall lower part 9 Reinforcement rib 10 Circular bead 10a Side wall upper part bead 10b Beads at the bottom of the side wall 11 Lower taper portion 12 Upper taper portion 13 Most recessed portion

Claims (4)

[Scope of utility model registration request] 1. A plastic bottle, which is formed by plastic blow molding or stretch blow molding and has circumferential sidewall beads formed in multiple stages, wherein the bead comprises a lower taper portion having a large inclination angle with respect to a horizontal plane. A bead having a reverse inclined upper taper portion with a small inclination angle, the most concave portion being biased upward, and the depth of the bead on the upper side wall is smaller than the depth of the bead on the lower side wall. Aseptic filling plastic bottle. 2. The inclination angle (α) of the lower taper portion is 60 to 80 degrees, and the inclination angle (β) of the upper taper portion is 30.
The plastic bottle for aseptic filling according to claim 1, which is at a temperature of from 55 to 55 degrees. 3. The plastic bottle for aseptic filling according to claim 1, wherein the depth of the bead on the upper portion of the side wall is one half to three quarters of the depth of the bead on the lower portion of the side wall. 4. The aseptic filling plastic bottle according to claim 1, wherein the plastic is formed of a thermoplastic polyester mainly containing ethylene terephthalate units, and at least the side wall portion is biaxially molecularly oriented by stretch blow molding.