CH707062A1 - Support Ring Clear plastic containers, especially plastic bottles. - Google Patents

Abstract

It is described a supportringloser plastic container (1) having a container body (2) and a pouring opening (20). In the region of the pouring opening (20), fastening means (6) for the positive fixing of a closure are provided in an outer wall (6) of the plastic container (1). In an area close to the fastening means (6) for the form-fitting fixing of a closure part, an at least partially encircling groove (10) is produced, which is produced in a blow molding process.

Description

The invention relates to a supportringlosen plastic container, in particular a plastic bottle, according to the preamble of claim 1.

The usual in the past containers made of white or stained, glass or ceramic are increasingly being replaced by plastic containers. In particular, for the packaging of fluid substances, for example, for household applications, agriculture, industry and commerce, etc., recently mainly plastic containers are used. The low weight and the lower costs certainly play a significant role in this substitution. The use of recyclable plastic materials and the overall more favorable overall energy balance in their production also contribute to demand from the users of the acceptance of plastic containers.

Single-layer or multi-layer plastic containers are often produced by the so-called extrusion blow molding method, in particular a tubular blowing method. The extrusion blow molding machines used for the extrusion blow molding process usually have one or more extruders for feeding the required plastic material. The outlet of the extruder is connected to an extruder head, at the outlet opening of which the extruded tube preferably exits in the opening width. The extruded plastic tube can be constructed in one or more layers. The hose exiting the outlet nozzle continuously or quasi-continuously is transferred to a blow molding tool assembly and inflated by overpressure with the aid of a blow mandrel retracted into the mold cavity. Thereafter, the inflated plastic container is removed from the mold cavity.

Plastic containers made of polyethylene terephthalate (PET) and similar materials are usually produced in a so-called stretch blow molding. In this case, a preform is first produced by injection molding in an injection mold. Recently, also flow molding or extrusion blow molding for the production of preforms have been proposed. The preform has a substantially elongate preform body and is formed closed at its one longitudinal end. At the other end of the preform body includes a neck portion, which is provided with a pouring opening. The neck portion already has the later shape of the bottle neck. On the outer side of the neck portion, therefore, threaded portions or the like protrusions are usually already formed for fixing a closure part. In many cases, a so-called snap ring is provided on the neck portion, which protrudes radially from the circumference. The snap ring serves as an abutment for a detachable guarantee strip of a screw-on screw cap for a plastic container blown out of the preform or for oil bottles or the like for fixing the lower part of a commonly used hinge closure. In most of the known preforms, the preform body and the neck portion are separated by a so-called support ring. The support ring protrudes radially and serves for the transport of the preform or of the plastic container produced therefrom and for the support of the preform on the molding tool or of the plastic container during the closure.

The preform is removed from the mold after its production and processed in a one-step stretch blow still hot immediately or cooled and stored in a two-stage stretch blow molding for spatially and / or temporally separate processing on a stretch blow. Prior to further processing in the stretch blow molder, the preform is conditioned if necessary, i. The preform is impressed on a temperature profile. Thereafter, it is introduced into a blow mold of the stretch blow molding apparatus. In the blow mold, the preform is finally inflated by means of a gas injected with overpressure, usually air, according to the mold cavity and additionally axially stretched with a stretching mandrel. An injection blow molding process is also already known, in which the blowing process takes place directly after the injection of the preform. The preform remains on the injection core, which at the same time forms a kind of stretching mandrel. The preform is in turn inflated by overpressure according to the mold cavity of a blow mold, which is delivered to the injection core or vice versa, and thereby stretched by the mandrel. Thereafter, the finished plastic container is removed from the mold.

The extrusion blown, injection blown or stretch blown plastic containers are i.d.R. transported and filled immediately after demoulding to a bottling plant.

After filling, the plastic containers are automatically closed with screw caps or snap closures. These are either screwed on, bounced or snapped.

For the sake of improved life cycle assessment but also for cost reasons, plastic containers, especially plastic bottles, are always made lighter and thin-walled. As a result of the resulting reduced mechanical strength of the plastic container, the torques, bouncing and snap forces occurring during closing can only be absorbed inadequately by the bodies of the plastic containers or undesirable deformations can occur. This problem can also occur in supportless plastic containers, which are stretch-blown from supportringless preforms, as described, for example, in WO 2006/027 092 A1 for wide-mouth containers. In conventional stretch blown plastic containers, the closure is applied to the relatively thick-walled, non-stretched neck portion. A usually arranged between the container body and the container neck support ring is used when closing the previously filled container for receiving the forces occurring. Due to the relatively large wall thickness in this area, the forces can be easily absorbed, although the unstretched material has a lower strength than the stretched. If the support ring is missing and the rest of the container body is very thin-walled with respect to the unstretched neck portion, problems may arise during the application of the closure.

Even with plastic containers, which are made according to the so-called "lost-neck process", the application of the closure can lead to problems due to the absence of the support ring. Such containers are first inflated like a plastic bottle in the mold cavity of a blow mold. In this case, in a section immediately following the container body, threaded sections, a thread or similar fastening means are blown for the form-fitting fixing of a closure. Subsequent to the blowing process, the neck portion of the plastic container located above the blown-off means for the positive locking of the closure is severed. The remaining container, which usually has an opening with a large opening diameter, is then transported to the filling station to be filled there and then provided with the closure. However, after the neck portion has been severed, this wide neck container does not have a support ring which could serve as an abutment when the closure is applied.

Object of the present invention is therefore to remedy the problems described, which can occur when applying a closure part on supportringlose plastic containers. It is to be created a supportringloser plastic container, which allows an optimization in terms of container weight and despite reduced wall thickness and lack of support ring allows easy automatic closure of the plastic container. In this case, the existing automatic closing devices should continue to be usable without complex redesigns.

The solution to these problems consists in a supportringlosen plastic container, in particular a plastic bottle, which have the stated in the characterizing portion of claim 1 features. Further developments and / or advantageous embodiments of the invention are the subject of the dependent claims.

The invention provides a supportringloser plastic container is provided which has a container body and a pouring opening. In the region of the pouring opening fastening means for the positive fixing of a closure are provided in an outer wall of the plastic container. The fastening means for the positive fixing of a closure may be, for example threaded sections, a thread or bayonet-like projections or grooves. In an area close to the fastening means for the positive fixing of a closure part, an at least partially encircling groove is produced, which is produced in a blowing process.

The at least partially circumferential groove in the vicinity of the fastening means assumes the function of a support ring in a supportless plastic container. The partially circumferential groove allows the coupling of a torque occurring when unscrewing a twist lock or bayonet closure or the absorption of the bounce or snap forces in a bouncing or snapping a closure part. The at least partially circumferential groove is arranged in a structurally stronger region of the plastic container and thus relieves the rest of the container body, which may be formed correspondingly thin-walled. The at least partially encircling groove on the plastic container is designed such that devices, such as transport, holding or closing devices, which are actually intended for plastic containers with usually sprayed support ring, can continue to be used.

The inventive design of the plastic container can be provided in bottle-like plastic containers as well as plastic containers, which are made by the Lost-Neck method.

In supportringlosen plastic containers, which are bottle-like, connects to the container body to a container shoulder, which is connected to a container neck. The container neck has the pouring opening and on its outer wall, the fastening means for the positive fixing of a closure. The blown, at least partially circumferential groove is formed in a container neck near the region of the container shoulder.

The at least partially encircling groove having container shoulder is structurally stronger than the rest of the container body, which may be formed correspondingly thin-walled.

The at least partially circumferential groove is conveniently located within the first third of the axial extent of the container shoulder from the container neck to the container body. In this area, the plastic container is less strongly radially and axially stretched, and the plastic container in this area usually also has a greater wall thickness than in the following sections of the container shoulder or the container body.

A measured in the axial direction width of the groove is about 2 mm to about 20 mm. The groove has a depth measured in the radial direction which is about 2 mm to about 20 mm. In the case of these dimensions of the groove, it is ensured that the inflated and possibly additionally stretched axially stretched plastic container in the stretch blow molding process can be removed from the mold without difficulty and the majority of the automatic closing devices usually used can be reused without redesigning.

A variant of the invention provides that the groove is formed as a circumferential annular groove. This facilitates the detection of the plastic container from the holding and closing devices in particular in that no radial orientation of the holding and closing devices to the plastic container is necessary.

Thus, a torque occurring when turning a rotary closure can be better absorbed, the boundary surfaces of the annular groove may be at least partially formed with a greater roughness than the adjacent outer wall. Additionally or alternatively, one or more abutments may be formed for receiving torque within the annular groove.

The one or more abutments may extend radially outward or in the direction of the container interior from a radial boundary surface of the annular groove. In this case, each abutment is formed as a projection or as a notch-like depression. The abutments facilitate the absorption or support of the torque that can occur through the closure device when turning a rotary closure on the container neck provided with threaded portions.

A further embodiment of the invention provides that in the vicinity of the at least partially encircling groove or to the circumferential annular groove, above and / or below the same in the adjacent outer wall, one or more abutments are formed for torque absorption. The abutments are formed, for example, as projections relative to the adjacent outer wall or as notch-like depressions in the adjacent outer wall. Preferably, the protrusions or notches have a radial extent of from about 1 mm to about 10 mm. Their axial extent corresponds approximately to the axial width of the annular groove. When applying, in particular unscrewing the closure on the container neck, the abutment can cooperate with appropriately designed holding devices on the Verschliesseinrichtungen to absorb the occurring torque and / or the occluding closing forces.

The abutments for torque absorption are like the at least partially encircling groove or the annular groove produced during the blowing process in a correspondingly shaped mold cavity of a blow mold.

The novel features prove to be for supportringlose plastic containers of advantage, which are produced in Extrusionsblas- or in a stretch blow molding. They are particularly expedient in the case of plastic containers, in particular plastic bottles, which are produced from supportringless preforms in a stretch blow molding process. They are also advantageous in plastic containers, which are produced by the Lost-Neck process.

Further advantages and features will become apparent from the following description of exemplary embodiments of the invention with reference to the schematic drawings, which are not shown to scale. <Tb> FIG. Fig. 1 shows a partially cutaway view of a supportringless plastic container, in particular a plastic bottle; <Tb> FIG. 2a -fig. 2c <SEP> show schematic cross sections through an annular groove in the region of a container shoulder; <Tb> FIG. 3a and 3b <SEP> show two further cross sections through the annular groove; and <Tb> FIG. 4 <SEP> is a view of a plastic container made by a lost-neck process.

Fig. 1 shows schematically a partially cut in the container neck representation of a total provided with the reference numeral 1 plastic container, such as a plastic bottle. The plastic container 1 is manufactured in a blow-molding process, for example in an extrusion blown process from an extruded plastic tube or in a stretch blow molding process from a preform previously produced, for example by injection molding or in a flow-compression process, and consists of the plastic materials commonly used for these processes, e.g. PE, in particular HDPE, PP, PET, PEN, PS, PLA, PA, as well as copolymers of these materials. It can be single or multi-layered.

The plastic container 1 has a container body 2, which is closed with a container bottom 3. About an approximately conical container shoulder 4, the container body 2 is integrally connected to a container neck 5. On an outer wall of the container neck 5 fastening means 6 are formed, which are formed in the present embodiment as threaded portions 6 or the like projections. The fastening means 6 are used for the positive fixing of a closure part, not shown. In the case of a plastic container produced in a stretch blow molding process, the threaded sections 6 are already finished on a preform previously produced in an injection molding or flow molding process and are not further changed during the subsequent blow molding process. In the extrusion blow molding method, the container neck with the external thread is first formed in the mold cavity of a blow mold on an inserted section of an extruded plastic tube. In many cases, as in the case of the plastic container 1 shown in FIG. 1, which is produced in particular from a supportless preform in a stretch blow molding process, a circumferential snap ring 7 is formed on the container neck 5. The snap ring 7 serves as an abutment for a detachable guarantee strip of a screw-on screw cap or in the case of oil bottles or the like for fixing a lower part of a commonly used hinge closure. In this case, ensures the below the snap ring 7 to the container neck 5 subsequent container shoulder 4, which widens conically in the direction of the container bottom 3 that the detachable tamper evident band of the screw can not be levered over the snap ring 7.

In an adjacent to the threaded portions 6 region of the container shoulder 4, approximately in the first third of the axial extent of the container shoulder 4 in the direction of the container body 2, in the boundary wall 9 of the container shoulder 4 by blow molding a groove 10 is formed. The groove 10 is formed at least partially circumferentially. According to the illustrated embodiment, the groove 10 is formed as a circumferential annular groove whose cross-section extends approximately perpendicular to an axis A of the plastic container 1. In the radial direction, the annular groove 10 is bounded by a radial boundary surface 11. The annular groove 10 has a width w measured in the axial direction, which is about 2 mm to about 20 mm. A measured in the radial direction depth d of the annular groove 10 is about 2 mm to about 20 mm. The surfaces bounding the annular groove 10 may have a greater roughness than the surface of the remaining boundary wall 9 of the container shoulder 4.

2a, 2b and 2c show schematically different cross-sectional contours of the annular groove 10. In this case, the cut surface runs approximately centrally the width w through the annular groove 10 and perpendicular to the container axis A. FIG. 2a shows the contour of the radial boundary surface 11 of the annular groove 10th in a rotationally symmetrical plastic container 1. The in Fig. 2b and 2c indicated cross-sectional contours of the annular groove 10 each show two abutment 16 for torque absorption. In Fig. 2b, these abutments 16 are formed by two projections 12 which extend within the annular groove 10 from the radial boundary surface 11 to the outside. Preferably, the projections 12 do not project beyond the annular groove 10. However, the projections 12 may be flush with the boundary wall 9 of the container shoulder 4 (FIG. 1). An inner wall of the radial boundary surface 11 extends into the projections 12. This is a consequence of the production of the projections 12 in a blowing process. The abutment 16 shown in Fig. 2c are formed as notches-like depressions 13 which extend from the radial boundary surface 11 of the annular groove 10 radially in the direction of the container interior. A radial length 1 of the recesses 13 or the projections 12 corresponds approximately to the radial depth d of the annular groove 10. Their axial extent corresponds approximately to the axial width w of the annular groove 10th

In the embodiments shown in Fig. 3a and 3b, the abutment 16 for torque absorption in close proximity above and / or below the circumferential annular groove 10 are arranged. 3a shows two projections 14 which project above and / or below the annular groove 10 substantially radially from the boundary wall 9 of the container shoulder 4. According to FIG. 3b, the abutments 16 are formed by two notch-like depressions 15, which extend inwards and / or below the annular groove 10 substantially radially inwardly from the boundary wall 8 of the container shoulder 4. The projections 14 or depressions 15 have a radial extension 1, which is about 1 mm to 10 mm. Their axial extent corresponds approximately to the width w measured in the axial direction w of the annular groove 10.

The at least partially encircling groove 10 in the container shoulder 4 in the vicinity of the threaded portions 6 or the like projections on the container neck 5 assume the function of a support ring in a supportless plastic container 1. The partially encircling groove 10 allows the coupling of a torque occurring when a screw cap is screwed on, or the absorption of the bounce or snap forces during a bouncing or snapping-on of a closure part. The at least partially encircling groove 10 is arranged in the region of the structure stronger container shoulder 4 and thus relieves the rest of the container body 2, which may be formed correspondingly thin-walled. Additional abutment 16 for torque absorption support the coupling of a torque occurring during the unscrewing of a rotary closure on the container neck 5 in holders of a closing device. While always two abutments 16 are shown in the figures, more or only one abutment 16 may be provided. It can also recesses 13,15 and projections 12, 14 may be provided in combination as an abutment 16. These can be arranged within the groove 10 or annular groove and / or above and / or below it.

Fig. 4 is a schematic representation of a plastic container made by a lost-neck method. In turn, the plastic container bears the reference numeral 1. It is produced in a blow molding process, for example in an extrusion blown process from an extruded plastic tube or in a stretch blow molding process from a preform previously made, for example, in an injection molding process or in a flow molding process and consists of the usual plastic materials used for these methods, such as PE, in particular HDPE, PP, PET, PEN, PS, PLA, PA, as well as copolymers of these materials. It can be constructed in one or more layers. The illustrated in Fig. 4 separated neck portion 30 is intended to indicate the production in the Lost-Neck process. At its outer wall near the pouring opening 20, the plastic container is in turn equipped with fastening means 6 for the positive fixing of a closure part. In contrast to bottle-like plastic containers, the fastening means 6 are designed for the form-fitting fixing of a closure part in a blow molding process. The plastic container 1 has a container body 2 which is closed by a container bottom 3. In the vicinity of the fastening means 6 for the positive fixing of the closure part, a groove 10 is formed in the adjacent outer wall 9 in the blowing process. The groove 10 is formed at least partially circumferentially. According to the illustrated embodiment, the groove 10 is formed as a circumferential annular groove whose cross section is approximately perpendicular to an axis A of the plastic container 1. The dimensions and the special design of the groove 10 correspond to those of the embodiment explained with reference to FIGS. 1 to 3 for plastic bottles.

Claims (17)

1. Supportless plastic container with a container body (2) and a pouring opening (20), the outer wall in the region of the pouring opening (20) fastening means (6) for the positive fixing of a closure part, characterized in that in one of the fastening means (6) for the positive Forming a closure member near portion is formed at least partially circumferential groove (10), which is produced in a blow molding process. 2. Plastic container according to claim 1, characterized in that it is made in a lost-neck process. 3. Plastic container according to claim 1, characterized in that it is bottle-shaped and has a container body (2) extending from the container shoulder (4) to which a container neck (5) adjoins the pouring opening (20) and the fastening means (6 ) for positive fixing of a closure part, and in that the at least partially encircling groove (10) in the container shoulder (4) is formed. 4. Plastic container according to claim 3, characterized in that the groove (10) within the first third of the axial extent of the container shoulder (4) from the container neck (5) to the container body (2) is arranged. 5. Plastic container according to one of the preceding claims, characterized in that the groove (10) has an axial width (w) which is about 2 mm to about 20 mm. 6. Plastic container according to one of the preceding claims, characterized in that the groove (10) has a radial depth (d), which is about 2 mm to about 20 mm. 7. Plastic container according to one of the preceding claims, characterized in that the groove (10) is designed as a circumferential annular groove. 8. Plastic container according to one of the preceding claims, characterized in that the annular groove (10) has boundary surfaces which at least partially have a greater roughness than an adjacent outer wall (9). 9. Plastic container according to claim 7 or 8, characterized in that within the annular groove (10) at least one abutment (16) is designed for torque absorption. 10. Plastic container according to claim 9, characterized in that the at least one abutment (16) extends from a radial boundary surface (11) of the annular groove (10) in the direction of an adjacent outer wall (9). 11. Plastic container according to claim 9, characterized in that the abutment (16) extends from a radial boundary surface (11) of the annular groove (10) in the direction of the container interior. 12. Plastic container according to one of the preceding claims, characterized in that in the vicinity of the at least partially encircling groove or the circumferential annular groove (10), above and / or below the same in an adjacent outer wall (9) one or more abutments (16 ) are designed for torque absorption. 13. Plastic container according to claim 12, characterized in that each abutment (16) as a projection (14) opposite the adjacent outer wall (9) is formed. 14. Plastic container according to claim 12, characterized in that each abutment (16) is designed as a notch-like depression (15) in the adjacent outer wall (9). 15. Plastic container according to claim 13 or 14, characterized in that each projection (14) or each notch-like depression (15) opposite the adjacent outer wall (9) has a radial extent (1) of about 1 mm to about 10 mm. 16. Plastic container according to one of the preceding claims, characterized in that the abutment (16) are made for torque absorption in a blow molding process. 17. Plastic container according to one of the preceding claims, characterized in that it is made of a supportringlose preform in a stretch blow molding.