WO2009066249A2

WO2009066249A2 - Blown plastic bottle with standing foot and method for the manufacture thereof

Info

Publication number: WO2009066249A2
Application number: PCT/IB2008/054856
Authority: WO
Inventors: Oskar Anthonie De Waal
Original assignee: Green Investments Bvba
Priority date: 2007-11-19
Filing date: 2008-11-19
Publication date: 2009-05-28
Also published as: WO2009066249A3; NL1034717C2

Abstract

The invention relates to a bottle (1), blown from plastic material, provided with a standing foot (2) manufactured from the same plastic material, which standing foot is connected to the bottle and the invention further relates to a method for forming a bottle, wherein the bottle is blown from a- pre-form and is connected to a standing foot, without using a hot melt or such bonding means not recyclable with the material of the bottle.

Description

Title: Blown plastic bottle with standing foot and method for the manufacture thereof.

The invention relates to a blown plastic bottle. The invention relates in particular to a blown plastic bottle with a standing foot.

Blown plastic bottles are known from practice, Here, from a preform, which is injection molded, a bottle is blown in a blow mold, by introducing air, while heating it, under high pressure into the pre-form, so that the pre-form is inflated and is pressed against the wall of a mold cavity of the blow mold. In this form, the bottle subsequently cools down.

In a first embodiment, a bottle is known which is provided with a standing foot which is attached against the underside utilizing a hot melt. The bottle is blown from PET or a PET blend, while the standing foot is formed from, for instance, PC or PE. Recycling such a bottle, at least the material thereof, is hard and can only be done at relatively high costs.

In a second embodiment, a bottle is known which has no standing foot. Such a bottle is provided with a specially formed bottom on which the bottle can stand. Such a shape involves, for instance, a pentaloid bottom which means that the bottom has five dents with intermediate lobes on which the bottle can stand. In a comparable manner, bottoms are known with more or fewer of such dents and lobes. Such a bottle can be manufactured from one material, for instance PET, and is thus better recyclable than the bottle with standing foot. However, such a bottle has as a drawback, inter alia, that it is poorly resistant to relatively high pressures, while furthermore, the bottom requires relatively much material, which is unfavourable because either wall thickness differences have to be provided or a relatively large wall thickness of the entire bottle is to be used. The invention contemplates providing a blown plastic bottle which obviates or at least reduces one of the drawbacks of the known bottles. In a first aspect, a bottle according to this specification is characterized in that the bottle is formed from a plastic, as is a standing foot connected thereto, while the plastic of the bottle and the standing foot can be jointly recycled. In particular, the bottle and the standing foot are manufactured from the same plastic, while more particularly a mono-material bottle is obtained.

In a second aspect, a bottle according to this specification is characterized in that the bottle is formed from a plastic, as is a standing foot connected thereto, the bottle being connected to the standing foot by means of a welding technique or by means of a different technique wherein no material is added or material is added which is not different from the material of the bottle and/or the standing foot or at least can be recycled therewith for reuse.

In a third aspect, a bottle according to this specification is characterized in that the bottle is connected with the standing foot by a clamping connection, form locking or the like. Preferably, the bottle is then at least partly blown into the standing foot.

In a fourth aspect, a bottle according to the specification is characterized in that the bottle and the standing foot are manufactured from PET or a PET blend,

In clarification of the invention, embodiments of a bottle and method for the manufacture thereof will be described in further detail on the basis of the drawing. In the drawing:

Fig. 1 shows, in cross-sectional side view, a bottle with a standing foot;

Fig. 2 shows, in cross-sectional side view, a step in a method for the connection of a standing foot with a bottle;

Fig, 3 shows, in cross-sectional side view, an alternative apparatus a method for connecting a standing foot to a bottle; and Fig. 4 shows a bottle in partly cross sectional side view with a standing foot.

In this specification, identical or corresponding parts have identical or corresponding reference numerals. The embodiments shown are shown merely by way of illustration and should not be construed to be limitative in any manner.

In this specification, material is understood to mean both a mono- material and a blend, unless expressly stated otherwise. In this specification, "the same material" for the bottle and the standing foot is understood to mean at least but not exclusively that to that purpose, materials are used which are jointly recyclable, for reuse, or similar materials, for instance materials with the same chemical components or composition. Herein, reuse is at least understood to mean that the recycled material is suitable for use in production processes which are the same or comparable to those with which the bottle and/or the standing foot have been manufactured. Preferably, the material is recyclable such that it can be used in the same material category as the original materials. Preferably, the bottle and the standing foot are recyclable, without prior separation, for instance as material of which the bottle is manufactured, such as, for instance, PET in case the bottle 1 is manufactured therefrom.

In this specification, substantially, approximately or such relative terms are understood to mean at least but not exclusively that deviations of at least plus or minus ten percent, in particular at least plus or minus five per cent, more particularly at least plus or minus 2% of a respective given value or condition are possible within the invention,

A bottle according to this specification is preferably manufactured from a plastic pre-form such as customarily used, which pre-form is for instance injection molded. Then, the pre-form is placed in a blow mold and heated therein and inflated until it has it final form. Then, the bottle is cooled BO that it becomes form-retaining. It is taken from the blow mold and used further, for instance filled with a beverage and closed by a cap.

On a bottom side, the bottle is provided with a separately formed standing foot which is fixedly connected to the bottle, in a manner to be described further. In one embodiment, this can be done in the blow mold. In an alternative embodiment, this can be done outside the blow mold.

A bottle according to the specification is preferably manufactured from PET, a PET blend or laminated PET. The material from which the bottle is manufactured can comprise more than 50% by weight of PET, for instance more than 60% by weight. In one embodiment, the material comprises more than 70% by weight, more particularly more than 80% by weight, for instance more than 90% by weight. The bottle can comprise, for instance, 95% by weight or more of PET, based on the entire bottle, inclusively any foils and additions used therein and/or thereon such as, for instance, barrier layers against gas exiting and/or entering the bottle, protection against radiation, ageing, coloring and the like, scavengers for, for instance, O2 or CO2 and/or decorative layers and the like, The bottle can also consist of virtually 100% PET. Preferably, the bottle is manufactured from food grade PET and/or "virgin" PET, which sometimes can be indicated as PET-I in a recycle symbol. A standing foot according to the specification, in the field of technology customarily indicated as bottom cap, is preferably manufactured from PET, a PET blend or laminated PET. The material from which the standing foot is manufactured can comprise more than 50 % by weight of PET, for instance more than 60% by weight. In one embodiment, the material comprises more than 70% by weight, more in particular more than 80% by weight, for instance more than 90% by weight. The standing foot can comprise, for instance, 95% by weight or more of PET, based on the entire standing foot, inclusive of any foils and additions used therein and/or thereon. The standing foot can also consist of virtually 100% PET. In an advantageous embodiment, the standing foot can be manufactured at least partly, preferably substantially and more particularly completely from recycled PET.

Ae indicated, the bottle and the standing foot are preferably manufactured from the same material, PET being particularly advantageous owing to the high degree of recyclability.

Alternatively, the bottle and/or the standing foot can be manufactured from other plastic materials, as long as jointly, these are recyclable in the same production process and yield a material with a purity of more than 60% by weight, in particular above 70% by weight, more particularly more than 60% by weight such as, for instance, more than 90% by weight and preferably more than 95% by weight. Preferably, the recycled material is in a purity category maximal for the respective plaβtic.

In Fig. 1 and 2, a bottle 1 with standing foot 2 according to the description is shown in a first embodiment, where, on the left hand side, a cross section is shown and, on the right hand side, an elevational view. This bottle 1 comprises a thin wall 3 of plastic, in particular PET, while the wall can be a monolayer wall (as shown) or a multilayer wall (not shown), provided with, for instance, one or more barrier layers, while for instance additions on or in the plastic can be provided, such as Oa and/or CO2 scavengers and the like, while the material of the bottle is still considered as mono-material. The bottle 1 is provided in a customary manner with a neck 4 on which for instance outer βcrew thread 5 can be provided for placing a cap (not shown). The neck 4 can be provided with a collar 6 with which a pre-form 22 (as 9hown in Fig. 3) can be retained in a customary manner in a blow mold during blowing of the bottle 1 and which can furthermore simplify handling the bottle 1. It is noted, for that matter, that the bottle can have any desired shape, also for instance without neck 4 and/or screw thread 5 and/or without collar 6.

On the side remote from the neck 4, a bottom 7 is provided, integrally formed with the wall 3, which bottom 7 is formed substantially as a segment of a sphere, in particular as a hemisphere in this embodiment (dome- shaped). It could, for that matter, also have a different shape, as long as it fits completely or partly in the standing foot 2. The spherical form has the advantage that it offers an ideal pressure distribution, so that the wall 8 of the bottom 7 can be relatively thin, for instance have approximately the same thickness as the wall 3. Also, stresses in the bottom due to blister formation can thus be minimized, removed and/or optimized.

The bottom 7 offers an additional advantage that a bottle 1 designed therewith can withstand relatively high pressures relatively well, for instance above atmospheric, without undesired deformations, also with relatively large volumes, for instance bottles with a content of 1.5 or 2 litres or more and/or with relatively small wall thicknesses, for instance smaller than the currently customary wall thicknesses for bottles suitable for carbonated beverages such as soft drinks and carbonated water.

The bottom 7 as such has as a drawback that the bottle 1 cannot stand straight thereon. Furthermore, the appearance of the spherical bottom 7 can be perceived as inconvenient or unpleasant. The standing foot 2 covers the bottom 7 at least partly, at least in side view of the bottle 1, and can furthermore offer a standing surface 9 on which the bottle 1 can stand. As indicated, the standing foot 2 is preferably manufactured from the same material as the bottle 1. The standing foot 2 can be manufactured through injection molding. Use can then advantageously be made of a method and/or apparatus in which in a mold at least one mold cavity is provided which has a movable wall part such that preferably, with substantially or completely closed mold, the plastic can be introduced into the mold cavity while the volume thereof is greater than that of the product to be formed, such as pre-form or standing foot, and can be moved during or preferably after introduction of the plastic so that the final product is substantially formed in that the mold cavity is brought in a form and volume which correspond with the product to be formed. Here, preferably, the movement of the movable wall part is controlled such that in the mold, the temperature of the plastic, in particular adjacent a flow front thereof, is hardly if at all reduced, or increases even slightly, so that the fluidity is maintained or even improved, until the mold cavity is filled at least for the gTeater part. Thus, especially thin-walled products can be manufactured, with low closing forces and short cycle times. Optionally, the temperature of the plastic, in particular of the flow front, can then be held as close as possible to the injection temperature, preferably in a range between approximately 5 degrees Celsius above and below it, at least until all plastic ia introduced and more particularly until the entire mold cavity is filled. Thuβ, for instance crystal formation in the plastic, in particular with PET, can be prevented or at least be minimized. Such apparatuses and methods are known from, for instance, WO03/039838 or WO04/O24416, These applications are included herein by reference, at least as to the molds, injection molding apparatuses and methods described therein.

In the embodiment shown, the standing foot 2 has a bottom part 10 and a wall part 11 connected to the bottom part 10 by a curved edge part 12. The edge part 12 substantially defines the standing surface 9. In the example shown, the bottom part 10 is for instance concave in the direction of the bottle 1, such that a middle part 13 thereof touches the apex 14 of the bottom 7 of the bottle 1. On the side remote from the edge part 12, the wall part 11 has a longitudinal edge 15 which in assembled condition abuts against the wall 3 of the bottle 1, for instance adjacent the transition of the wall 3 and the bottom 7. The longitudinal edge 15 can be connected to the wall 3 of the bottle. Additionally or alternatively, the bottom part 10 can be connected to the bottom 7. In a bottle 1 with standing foot 2 according to this embodiment, each connection between the standing foot 2 and the bottle 1 is preferably obtained through a method in which no material is added, such as glue or hotmelt, because these impede or even render impossible recycling of the bottle and standing foot without polluted recycling material being obtained. To that end, use can for instance be made of a welding method, such as ultrasonic welding, as schematically represented in Fig. 2, spin welding, pressure welding or other welding¹ techniques without material additions, In an alternative embodiment, the or each connection can be obtained by adding material which can be recycled together with the bottle and the standing foot, such as, for instance, welding with the aid of a plastic welding rod, of the same plastic as the bottle and the standing foot.

In Fig. 2, it is schematically shown that a bottle 1 can be disposed in a βtanding foot 2, for instance on a rotating platform 16, after which the bottle 1 and the standing foot 2 are rotated about the longitudinal axis 17 of the bottle, in the direction of arrow Pi. Then, for inβtance an ultrasonic welding head 18 is held near or against the longitudinal edge 15 and the wail 3, so that the plastic of the longitudinal edge 15 and/or the wall 3 are somewhat heated and fuse together, whereby they are connected to each other at least after cooling. In a comparable manner, other welding techniques can be utilized. It will be clear that also for instance biodegradable glue can be utilized for connecting the standing foot to the bottle, or a glue which upon heating to above the temperature of use or to near or above the melting temperature of the plastic burns or evaporates or disappears in another manner from the material to be recycled or disappears in a conventional washing process of PET to be recycled.

In Fig. 3, schematically, a blow mold 20 is shown, in cross section, for forming a bottle 1. In the example shown, the mold 20 comprises two mold parts 2OA, 2OB which can be moved apart from a closed condition (as shown in Fig. 3) in the direction of the arrows P≥ and P3, so that the mold is opened and the mold cavity 21 is released for taking out a bottle 1 and/or placing a standing foot 2. In Fig, 3, on the top side, a pre-form 22 is suspended from the collar 6, so that a body 23 projects into the mold cavity 21, In this condition, hot air (or another pressure fluid such as a gas or liquid) can be introduced into the body 23 of the pre-form 22, in the direction B, whereby pressure exerted is such that the pre-form 22 is blown to form a bottle 1. To that end, in a customary manner, use is made of a blow head (not shown) which can connect to the neck 4, The mold cavity 21 can, for instance prior to and/or during blowing, be heated, for instance through heating of the mold cavity, walls thereof or similar measures known per se. In the embodiment shown in Fig, 3, a standing foot 2 is placed on the bottom 24 of the mold cavity 21, In this embodiment, the standing foot 2 haβ a bowl part 25 and a wall 26, interconnected by an edge part 27. In the exemplary embodiment shown, under the bowl part 25, partitions 28 are provided, for instance four (two in the plane of the drawing and two at right angles thereto), which are connected preferably centrally below the bowl part 25, and support the bowl part 25. The partitions 28 for that matter can also be omitted or a different number of partitions 28 can be provided or they can be placed differently. For instance, a grid of partitions can be provided, The purpose of the partitions can be support of the bowl part, in particular during blowing of the bottle 1, absorbing pressure in the bottle and/or providing improved rigidity of the standing foot, in particular with small wall thicknesses of the wall 26 and/or the bowl part 25. Preferably, the standing foot 2 is manufactured in one piece from plastic, in particular the same plastic as the bottle, for instance through injection molding, In this embodiment, the edge part 27 is designed such that it reaches slightly inwards in part and thus forms an undercut 29. Here, the form can be selected such that the edge part 27 comprises a curved edge 30 having, on an inner side thereunder, a wall part 31 which is somewhat receded, When the pre-form 22 is inflated, the wall 32 thereof will become thinner and be pressed against the wall 33 of the mold cavity 21. Furthermore, the wall 32, and in particular the part of the pre-form forming the bottom 7 will then be blown into the standing foot 2, against the bowl part 25 thereof and against the undercut. As shown in Fig. 4, a curved wall part 34 is then formed that encloses the edge part 27 and effects a form closure. Here, preferably, the wall part 31 is moved outwards, below the edge 30, so that additional pressure stress is obtained and an even better confinement. Through a correct choice of the temperature of the pre-form and the mold cavity, in one embodiment, a partial fusion of the material of the standing foot 2 and the bottle 1 can be obtained, so that a fixed connection is obtained, also when a βtanding foot according to for instance Fig. 1 is utilized.

In Fig. 4, a bottle 1 with standing foot 2 is shown, formed, for instance, in a mold 20 according to Fig. 3, where on the left hand side, a partial cross section is shown and on the right hand side an elevational view. With a standing foot 2 according to Figs. 3 and 4, where a bowl part 25 is utilized, the advantage is achieved that the bottom 7 of the bottle 1 can simply be suitably formed, such as spherical, while the pressure exerted during blowing can be absorbed by the bowl part 25 and optionally the partitions 28. Also with pressure increase in the bottle 1, during use, for instance through temperature increase and through CO2 or other gas developing or ejdting, the pressure can be absorbed at least partly by the bowl part 25.

In a variant (not shown), in a middle part of the bowl part 25, one or more openings can be provided, through which the bottle 1 can be blown, so that it can comprise a widening under the bowl part so that an additional or alternative bonding can be obtained. To that end, for instance a part of the bottom 7 can be blown through such an opening, whereupon the part reaching through the opening can be slightly upwardly flattened, forming a widening under the bowl part. In one embodiment, the standing foot 2 in the mold cavity 21 can, at least partly, be cooled or at least be protected against heating to near or above the melting point, The bottom 24 of the mold cavity 21 can be formed such that it supports the bowl part 25 completely or wholly for instance through raised portions on or of the bottom 24, so that this bowl part 25 and/or the bottom 1 can be designed to be, for instance, particularly thin, optionally without partitions, and can still withstand the blowing pressure when the bottle ia blown. Also, in such an embodiment, the bowl part 25 can be omitted wholly or partly.

With a bottle 1 according to this specification, a wall 3 and a bottom part 7 can be formed having the same wall thickness virtually all over. This is technically and economically advantageous. A minimum of material and weight is required for forming a pressure resistant bottle, also with volumes above for instance 1.5 or 2 litres, such as, for instance, approximately 3 to 5 litres or more, while furthermore the shape of the bottle is preserved to relatively high pressures, for instance more than approximately 1.3 bar, more particularly more than approximately 1.6 bar, such as, for instance, more than 2 bar or more than 4 bar, or at least with comparable pressures which can occur at room temperature or thereabove with carbonated beverages in closed bottles. In general, a bottle 1 according to this description can be formed from a material that is the same as the material from which a standing foot connected to the bottle is formed, while the connection between the standing foot and the bottle is formed without using a hot melt or other bonding means which is not recyclable with the material mentioned, in particular in an economically and technically useful manner. Preferably, the bottle and the standing foot are at least substantially manufactured from PET or PET blends.

The invention is not limited in any manner to the embodiments represented in the description and the drawings. Many .variations thereon are possible within the framework of the invention as outlined by the claims. For instance, the bottle and/or the standing foot can have other forms and be blown in a differently built-up mold. The neck can be designed differently while furthermore, the bottle may have integrally formed parts such as a handle, surface profiles such as ribs, edges, faces and the like. Labels and sleeves can be provided, arranged or not arranged in the mold cavity, The standing foot can also be utilized with bottles that can be laid on the wall 3, while the standing foot (bottom cap) is provided only for cover and/or pressure absorption and can for instance be designed such that the bottle cannot stand thereon in a self-supporting manner. Combinations and permutations of parts of the embodiments shown are understood to fall within the invention. Also, combinations and permutations of described connecting methods can be utilized within the invention. These and comparable variations are understood to fall within the framework of the invention.

Claims

1, A bottle, blown from plastic material, provided with a standing foot manufactured from the same plastic material, which standing foot is connected to the bottle,

2. A bottle according to claim 1, wherein the bottle and the standing foot are mutually connected such that they are jointly recyclable.

3. A bottle according to claim 1 or 2, wherein the standing foot is connected to the bottle without use of a hot melt.

4, A bottle according to any one of the preceding claims, wherein the standing foot is connected to the bottle at least through welding.

5. A bottle according to claim 4, wherein the bottle is connected to the standing foot at least through ultrasonic welding, spin welding or pressure welding.

6. A bottle according to any one of the preceding claims, wherein the standing foot is connected to the bottle at least through clamping and/or form locking.

7. A bottle according to any one of the preceding claims, wherein the bottle and the standing foot are manufactured from PET or a PET blend.

8. A bottle according to any one of the preceding claims, wherein the bottle and the standing foot are jointly recyclable as PET,

9. A bottle according to any one of the preceding claims, wherein it is designed for pressurized liquid such as carbonated (CO≥ containing) beverage.

10. A bottle according to any one of the preceding claims, wherein the volume of the bottle is at least 1.5 litres, more particularly at least 2 litres.

11, A bottle according to any one of the preceding claims, wherein the bottle in blown condition has a wall and a bottom part having substantially equal wall thicknesses.

12. A bottle according to any one of the preceding claims, wherein the bottle has a bottom part which substantially forms a spherical segment, such as approximately a hemisphere.

13. A method for forming a bottle, wherein the bottle is blown from a pre-form and is connected to a standing foot, without utilizing a hot melt or like bonding agent not recyclable with the material of the bottle.

14. A method for forming a bottle with a standing foot, in particular according to claim 13, wherein the bottle and the standing foot are manufactured from the same material.

15. A method according to claim 13 or 14, wherein the standing foot is at least connected to the bottle through welding.

16. A method according to claim 13 or 14, wherein the standing foot is at least connected to the bottle through form closure and/or clamping.

17. A method according to any one of claims 13 — 16, wherein the standing foot is manufactured through injection molding in a mold provided with a mold cavity with a movable wall part, wherein the plastic is introduced into the mold cavity with the movable wall part in a position such that the mold cavity has a relatively large volume and is moved in the mold cavity through movement of the wall part to a position wherein the volume of the mold cavity substantially corresponds with the volume of the standing foot.

18. A method for forming a bottle with a standing foot, wherein the bottle is at least partly blown into the standing foot.

19. A method according to claim 16, wherein the standing foot is placed in a mold cavity of a blow mold and the bottle is blown in the blow mold.

20. A method according to claim 19, wherein the bottle is connected to the standing foot in the blow mold.