WO1997022520A1

WO1997022520A1 - Method for producing a plastic container and preform for producing a plastic container

Info

Publication number: WO1997022520A1
Application number: PCT/EP1996/005269
Authority: WO
Inventors: Krister Bruhn
Original assignee: Tetra Laval Holdings & Finance S.A.
Priority date: 1995-12-19
Filing date: 1996-11-28
Publication date: 1997-06-26
Also published as: TW335386B; AU1094697A; EP0868347A1; DE19547425A1; JP2000502019A

Abstract

The invention relates to a method for producing a full, closed plastic container for flowing medium and having a pouring spout. Said method enables operation of simpler filling machines by cancelling complete procedural steps and is characterised in that a tubular section (5) with a threadless part (8) and a part (6) with an internal winding is attached to the plastic-container pouring spout with an external thread. The plastic container is filled through the tubular section (5) and the pouring spout and, when filled, is closed in that the threadless part (8) of the tubular section (5) is sealed by thermoforming.

Description

Process for producing a plastic container and preform for producing a plastic container

The invention relates to a method for producing a filled and closed plastic container for flow agents, which has a pouring spout. Furthermore, the invention relates to a preform made of thermoplastic material with an external thread and a retaining ring attached to the bottom end of the thread for producing a plastic container.

Numerous systems and methods for producing, including for molding and filling, plastic containers, in particular bottles, are known. So there are z. B. a method in which a preform made of plastic is blown into the final form forming the plastic container, in particular to the bottle. The bottle is sterilized, dried and then filled. A sealing film or a screw cap is also sterilized and sealed onto the filled, aseptic bottle. In a last process step, the screw cap is usually attached to the filled bottle. Filling systems that work according to the known method require at least two different sterilization units for aseptic filling of the product. One sterilization unit for the bottle and another sterilization unit for the bottle cap. In addition, the bottle cap sometimes consists of a multi-layer sealing film and a screw cap.

A bottling company that operates a bottling plant using a known method must therefore buy and stock at least two of the three different parts - a preform, a sealing film and a screw cap. To process these three different parts, a highly integrated filling machine is required, which is able to assemble these three different parts into a filled and sealed bottle.

The object of the invention is to provide a process for the production of a plastic container for plasticizers of the type mentioned at the outset and a preform for the production of a plastic container in such a way that the operation of simpler filling machines is possible and entire process steps of the known production processes are omitted, and storage is also simplified if necessary . This object is achieved for the method according to the invention in that the plastic container, on the pouring spout of which an external thread is attached a pipe section with a thread-free part and a part with an internal thread, is filled by the pipe section and the pouring spout, and in that the filled container is closed in that the thread-free part of the pipe section is closed by thermoforming.

If you ensure that a plastic container is available for the method according to the invention, on the pouring spouts of which an external thread is attached a piece of pipe of the type described, the filling and closing can be carried out in a much more economical manner than was previously possible. From the process step of filling, only the container itself needs to be conveyed and treated, no more other closing parts, such as. B. a sealing film or a screw cap. A piece of pipe attached to its pouring spout is moved in one piece with the plastic container. Since it is attached to the plastic container, special transport measures, application devices and the like are dispensed with without the closure means interfering. The pipe section is namely open, so that the container can be filled through this and the pouring spout.

The closure is also surprisingly advantageous because the unthreaded part of the pipe section is deformed by heat in such a way that the pipe section is then closed or the pipe section has become a screw cap. In addition, the thermoforming of the screw cap gives ergonomic lid shapes, which make it easy to open the bottle by improving the gripping properties of the screw cap. The screw cap can also be given an individual shape by thermoforming in such a way that the consumer can recognize a certain brand from it. Ultimately, this means that consumers can easily identify different brands.

It is possible to attach or apply the pipe section, which has a part with an internal thread, by screwing or injection molding onto the pouring spout of the plastic container. In particular, by injection molding the described pipe section onto the pouring spout of the plastic container, sealing properties are reliably ensured without additional measures. Alternatively, the pipe section can be manufactured separately beforehand and then connected to the pouring spout of the plastic container in a preferably aseptically sealed manner.

In an advantageous further embodiment of the invention, for the manufacture of the plastic container, on the pouring spout with an external thread, a tube piece with a thread-free part and a A part with an internal thread is attached, a pipe piece with an internal thread is applied to the external thread of a blow molding, and then the blow molding is inflated to a final shape forming the plastic container. This embodiment differs from the former in that the plastic container, to the pouring spout of which the piece of pipe is attached in the manner described, is not assumed to be present, from which the process steps of filling and closing proceed, as described above; rather, the last-mentioned measures describe here how such a plastic container (with an applied tube piece) is manufactured, namely using a blow molding known per se. It is understood that this consists of the desired plastic from which the container is ultimately to be formed. In contrast to known methods, however, according to the invention, the pipe section mentioned is applied to the blow parison, either by screwing on after a pipe section has already been produced or by injection molding, by means of which the pipe section is first produced around the external thread of the blow parison. According to the invention, the blow parison is thus joined together with the tube piece to form a preferably aseptically sealed unit, and the measures according to the invention for inflating, filling and closing take place in the manner described above. In initial tests it has been shown that the described plastic container (with the pipe piece applied) can also be produced by inflating a blow molding when the pipe piece is applied to the external thread of the blow molding. This results in particularly favorable manufacturing processes for the ultimately filled and closed plastic container.

For example, if you want to fill aseptic products, e.g. B. milk, then the plastic container, which is made with the inventive method, may not need to be subjected to a sterilization process separately at all. To inflate, the blow parison must be heated to a temperature that can also be used for sterilization. In other words, the blow parison becomes so hot anyway before the plastic container is finished that it can be regarded as sterile on the inside after being inflated. If this sterilization or a separate sterilization has been carried out together with the attached pipe section, then there is no need for additional sterilization processes such as a separate screw cap. B. or an additional sealing film, as is inevitable in known methods. Again, the measures according to the invention result in the advantage that only a single sterilization process is used.

Plastic containers, e.g. B. bottles or other packaging, manufactured by the pack manufacturer and made available to a bottler. Using the invention According to the method, the bottler can make do with just a single molding as a supplier part. A separate sealing film and separate screw caps are saved. Due to the fact that the blow parison is supplied as a unit with the pipe section applied, the molding and filling machine can be much easier for the bottler. Only a single sterilization process is required if sterile packaging is involved. A separate sterilization of a sealing film or a screw cap is not necessary. The bottler also no longer needs application devices for screw caps in the filling operation of his machine. It goes without saying that the filling machine is considerably simplified as a result.

By placing the pipe piece on the blow parison and thus ultimately the plastic container to be filled, the filling height in the container is surprisingly increased, because the pipe piece which has not yet been closed provides more head space for filling the container.

Both of the above-described methods according to the invention allow the bottle to be closed by thermoplastic deformation and sealing of the pipe section. The thermoforming of the pipe section can be carried out in such a way that the screw cap ultimately created is given a special, possibly individual shape. The advantage of better gripping of such a screw cap and thus improved opening has already been mentioned. The visual effect of the special lid shapes and the easier differentiation of different products through such locking devices were mentioned.

It is furthermore expedient according to the invention if the container consisting of thermoformable plastic is sterilized before filling. There is no need for several sterilizations for several parts separately, but the plastic container or the blow parison is sterilized once because the tube piece connected to the container is treated as an integral part of the plastic container, so to speak.

It is also advantageous if, according to the invention, a rupture seal or a seal is applied between the blow parison and the pipe section. The break-open seal, like the conventional insertion of a seal, serves to better seal the pipe section against the pouring spout of the later container, because the pipe section ultimately becomes a kind of screw cap. The break-open seal is provided in a particularly expedient manner between the outer end face of the pouring spout of the later container on the one hand and the correspondingly opposite surface of the pipe section on the other hand. In a special embodiment, the pipe piece is screwed onto the external thread of the pouring spout Container, then it is not necessary to insert a seal if it is planned to attach the break-open seal. In this case, a fine seal is applied along the annular gap between the two mentioned interfaces of the two parts (pouring spout and pipe section). It is a break-open seal, because the thin, fine design of the seal makes it easy to break open when the end user rotates the screw cap, which was formed from the pipe section, relative to the plastic container and thus opens it. In addition to the tightness that results from such a seal, even if it is designed to be fine and thin, the application of the break-open seal according to the invention has the further advantage that bacteria or similar contaminants cannot penetrate into the annular gap of the two parts mentioned.

According to the invention, hydrogen peroxide can also be used for the sterilization, in particular if it is desired to subsequently sterilize the plastic container before filling it. It is also advantageous if the plastic container according to the invention is a PET bottle. The production of PET bottles is well known. However, the connection of the same with a piece of pipe before filling in the sense of the measures according to the invention is unexpected. This has the advantage that blow molds made of PET can be purchased and processed with the method according to the invention, with the result that many known method steps can be adopted and proven, known devices are available. Furthermore, initial tests have shown that even plastic containers made of PET can be sterilized with hydrogen peroxide using the method according to the invention.

Furthermore, according to the method according to the invention, the thermoformable pipe section can be ergonomically shaped in order to improve the gripping properties of the resulting screw cap, so that the plastic container can be opened more easily by the consumer.

In a further advantageous embodiment of the invention, in the case of a preform made of thermoplastic plastic material with an external thread and a retaining ring attached to the bottom end of the thread, a piece of pipe made of thermoformable material is applied to the thread. The tube piece itself is open and can be designed so that it does not reduce the filling cross section of the pouring spout of the plastic container. A piece of pipe of the type described can either be produced separately by injection molding and then attached to the external thread of the pouring spout by screwing, pressing on or the like; or the pipe section can be applied to the pouring spout immediately by spraying. It is also advantageous if a seal is arranged between the preform and the pipe section or if, in an alternative embodiment, a break-open seal is applied between the preform and the pipe section. With a seal or with a rupture seal, a preform is created by the measures according to the invention which - without the pipe section - by known manufacturing methods, such as. B. injection molding can be produced. Known manufacturing technologies can be used both for the preform itself and for the pipe section itself. It is favorable according to the invention if the blow parison and the pipe section are connected to one another by means of an applicator. Then you have the workpiece that is favorable for further and simplified processing (further process steps), which after carrying out the described process steps ultimately leads to a screw cap which can be opened and closed several times.

When working on the blow molding, the known stretch blow molding process can be used to shape the plastic container that is ultimately desired. When working on the preform, it is then inflated together with the pipe piece applied. The plastic container is then ready for filling. If it is sterilized by the temperatures of the stretch blow molding process, further sterilization is unnecessary. However, if this is necessary in the event that one does not work from a preform but from a plastic container onto which the pipe section is first attached after the stretch blow molding process and molding, then the container can be sterilized in an expedient manner together with the pipe section, after which the filling and sealing by thermoforming.

The method according to the invention allows the creation of simpler molding and filling systems. Simpler means that fewer procedural steps are required, which means that a system with fewer functions and fewer assemblies is also required. In particular, with regard to known functions and devices, the use, transport, sterilization, positioning and sealing of sealing films are omitted when using the method according to the invention. Likewise, all functions and devices that guarantee the feeding, transport, positioning and fitting of screw caps in conventional molding and filling systems are eliminated. Likewise, the filler does not have to store sealing foils and screw caps. Instead of at least two different individual parts, which had to be formed for the finished container and assembled into this, only one individual part is processed in the method according to the invention.

By dispensing with the conventional sealing film, the process according to the invention can advantageously be used to form, fill and seal a plastic container which is completely made up of recyclable material is made. It is particularly advantageous that the absence of a sealing film means that material no longer has to be separated in order to make the container recyclable.

Further advantages, features and possible applications of the present invention result from the following description of preferred embodiments in conjunction with the attached drawings. Show it:

Figure 1 is a cross-sectional view of a blow molding through a round bottom

(hemispherical) is closed, Figure 2 is a cross-sectional view of a pipe section,

FIG. 3 shows a cross-sectional view of the blow parison with a tube piece attached,

Figure 4 is an enlarged view of the detail of the dashed circle IV in

FIG. 3, FIG. 5 the plastic container as a blown bottle with a tube piece attached,

FIG. 6 shows the sterilization of the plastic container according to FIG. 5,

FIG. 7 the filling of the plastic container of FIG. 5,

FIG. 8 shows schematically the pressing and shaping tool for closing the pipe section,

Figure 9 shows the pipe section in the form of a closed screw cap after removal of the

Tool and after the method step of closing, Figure 10 is a view of the plastic container with a closed screw cap in a state rotated by 90 ° with respect to Figure 9 about the longitudinal axis (the

Bottle) of the container, Figure 11 is a view similar to Figure 4, but on an even larger scale with the

FIG. 12 shows a similar view to FIG. 11, but with a sealing ring inserted instead of the break-up seal, FIG. 13 shows a cross-sectional view similar to that of FIG. 2, but of a different embodiment, and FIG. 14 shows an enlarged view the section of the solid circle XIV in FIG. 13.

The blow molding generally designated 1 in FIG. 1 has an elongated shape, is provided at the bottom with an approximately hemispherical base 2 and at the top with an external thread 3, on the bottom end of which a retaining ring 4 is formed. This blow molding is made of PET. In Figure 2, the generally designated 5 pipe section is shown in cross section, which has a part 6 with an internal thread 7 and above a part 8 without thread in an approximately cylindrical jacket shape. The pipe section 5 is continuously open, and its internal thread 7 fits the external thread 3 of the blow parison 1.

It is possible to screw the pipe section 5 onto the external thread 3 of the blow parison 1, so that the state shown in FIG. 3 results. The blow parison 1 is connected to the pipe section 5 by screwing or pressing on (possibly also by injection molding in situ) in such a way that an integral element consisting of the blow parison 1 and the applied pipe section 5 results. For the purpose of tightness and better sterilization, it is expedient to provide special measures at the point of the arrow 11 of FIG. 4 between the annular surface 9 of the preform 1 and the annular shoulder 10 of the tube piece 5.

For this purpose, according to an embodiment in FIG. 11, a representation similar to FIG. 4 has been broken off and greatly enlarged, but with the longitudinal center line 12 of the blow molding 1, which coincides with the longitudinal center line 12 of the pipe piece in the screwed-together state of FIG. 3. A rupture seal 13 is introduced between the annular surface 9 of the blow parison 1 and the annular shoulder surface 10 of the pipe section 5 arranged parallel thereto. It is an annular, fine and narrow, additional sealing seam 13, which connects the two parts, namely the blow molding 1 and the pipe section 5. At the same time, this sealing seam 13 is easy to break open, which is why the measure shown between the surfaces 9 and 10 in FIG. 11 is also referred to as a break-open seal 13.

In another embodiment according to FIG. 12, an annular seal 14, for example made of silicone rubber, lies between the surfaces 9 and 10.

The blow-molded preform 1 firmly connected to the pipe section 5 according to FIG. 3 (possibly with the properties according to FIGS. 4, 11 or 4, 12) is now blown to form the vial-shaped container. This is done with the pipe section 5 attached. The product is shown in cross section in FIG. 5.

In a further process section, the container formed by the stretch blow molding process, which is now designated 14 after blowing, is sterilized together with the applied tube piece 5. FIG. 6 schematically shows the process in which a sterilization tube 15 is used Hydrogen peroxide is blown into the plastic container 14 according to arrows 16 and 17 and guided to the inner walls.

In a further method step, the sterilized container 14 is filled through the pipe section 5. FIG. 7 shows the filling process with filling tube 18, the filling material 19 which is just emerging and the flow agent 19 'which has already been filled in.

FIG. 8 shows schematically (without filling material) the state of the pressing and shaping tool 20, 20 'immediately before thermoforming and thus deforming the pipe section 5.

If the two tool parts 20, 20 'move together according to the arrows 21, 21' and press the tubular part 8 of the pipe section 5 without thread, the screw cap, now designated 22, results on the pouring spout of the container 14, designated 23, for closing in a transverse sealing seam 24 is introduced into the tube. If the container of FIG. 9 is rotated by 90 ° about the longitudinal central axis 12 (not shown), then one sees the container 14 in FIG. H. with closed screw cap 22.

The preform 1 made of thermoplastic material with the external thread 3 and the retaining ring 4 attached to the bottom end of the thread 3 is used for the production of a plastic container 14 and represents a tradable element in the manner of an intermediate product. This preform 1 is used in a particularly preferred manner for implementation of the method for producing the plastic container 14 for flow agent described, filled and closed, which has the pouring spout 23.

FIGS. 13 and 14 show a further embodiment of the pipe section 5. For aseptic sealing, the part 6 with the thread 7 on the shoulder 10 is provided with a sealing lip 25. Radially outside of this, there is a reinforced shaped shoulder 26 in order to better transmit those forces which arise when applying to the preform or the package which has not yet been filled.

Claims

Patent claims

1 . A process for the production of a filled and closed plastic container (14) for flow agents, which has a pouring spout (23), characterized in that the plastic container (14), on the pouring spout (23) with external thread (3), is a piece of pipe (5) with a thread-free one Part (8) and a part (6) with an internal thread (7) is attached, is filled through the pipe section (5) and the pouring spout (23) and that the filled container (14) is closed by the fact that the thread-free part (8 ) of the pipe section (5) is closed by thermoforming.

2. The method according to claim 1, characterized in that for the production of the plastic container (14), at the pouring spout (23) with an external thread (3) a pipe section (5) with a thread-free part (8) and a part (6) with an internal thread (7) is attached, a pipe section (5) with an internal thread (7) is applied to the external thread (3) of a blow molding (1) and then the blow molding (1) is inflated to a final shape forming the plastic container (14).

3. The method according to claim 1 or 2, characterized in that the thermoplastic plastic container (14) is sterilized before filling.

4. The method according to any one of claims 1 to 3, characterized in that a rupture seal (13) or a seal (14) is attached between the blow parison (1) and the pipe section (5).

5. The method according to any one of claims 1 to 4, characterized in that hydrogen peroxide is used for sterilization.

6. The method according to any one of claims 1 to 5, characterized in that the plastic container (14) is a PET bottle.

7. The method according to any one of claims 1 to 6, characterized in that the thermoformable pipe section (5) is ergonomically shaped.

8. preform made of thermoplastic material with an external thread (3) and a retaining ring (4) attached to the bottom end of the thread (3) for producing a plastic container (14), characterized in that a pipe section (5) made of thermoformable material is applied to the thread (3).

9. Preform according to claim 8, characterized in that a seal (14) is arranged between the preform (1) and the pipe section (5).

10. Preform according to claim 8 or 9, characterized in that between the preform (1) and the pipe section (5) a break-open seal (13) is attached.