EP3187430A1 - Support ring-free plastic container, especially plastic bottle - Google Patents

Abstract

There is described a supportringloser plastic container (1) having a container body (2) and a container neck (5) with a pouring opening (20). In the vicinity of the pouring opening (20) fastening means (6) are provided for the positive fixing of a closure in an outer wall (6) of the plastic container (1). In a region between the container neck (5) and the container body (2), in a region close to the fastening means (6) for the positive fixing of a closure part, a circumferential annular groove (10) is produced, which is produced by a blowing process. Within the annular groove (10) is formed at least one abutment (16) for receiving torque.

Description

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

The usual in the past containers 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 promoting the acceptance of plastic containers among the users.

Single-layer or multi-layered 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 inserted 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 process. 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 are proposed Service. The preform has a substantially elongated 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 demolded after its production and still processed hot immediately in a one-stage stretch blown or cooled and stored in a two-stage stretch blown for a spatially and / or temporally separate further 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 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 usually transported immediately after demolding to a filling plant and filled.

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

For reasons of an improved life cycle assessment but also for reasons of cost, plastic containers, in particular plastic bottles, are being made lighter and thinner-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 supportringlose preforms, as for example in the WO 2006/027092 A1 are described for wide-mouth container. 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 manufactured according to the so-called "lost-neck method", 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 to be 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 supportless 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 having a container body and a container neck with a pouring opening. In the vicinity of the pouring opening fastening means for the positive fixing of a closure are provided in an outer wall of the container neck. 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 a region adjoining the container neck in the direction of the container body, an encircling annular groove is produced, which is manufactured in a blow molding process. Within the annular groove at least one abutment is designed for torque absorption.

The annular groove in the vicinity of the fastening means assumes the function of a support ring in a supportless plastic container. The circumferential annular groove with at least one abutment allows the coupling of a torque occurring when unscrewing a rotary closure or bayonet closure or the inclusion of the bounce or snap forces in a bouncing or snapping a closure part. The circumferential annular groove is in a structurally stronger area of the plastic container arranged and thus relieves the rest of the container body, which may be formed according to thin-walled. The circumferential annular groove in the region of the plastic container located between the container neck and the container body is designed so that devices, such as transport, holding or closing devices, which are actually provided for plastic containers with conventionally molded support ring, can continue to be used. The circumferential annular groove 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.

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

The peripheral annular groove having region is structurally stronger than the rest of the container body, which may be formed correspondingly thin-walled. The annular groove portion may be formed as a container shoulder connecting the container neck and the container body.

The circumferential annular groove is expediently arranged 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 annular 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.

The abutment (s) may extend radially outward or toward the interior of the container 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 circumferential annular groove, above and / or below the same in the adjacent outer wall, one or more abutment for torque absorption are formed. 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 torque occurring and / or the occluding closing forces.

The abutments for torque absorption are like the circumferential annular groove produced during the blowing process in a correspondingly shaped mold cavity of a blow mold.

The features according to the invention prove to be advantageous for supportringless plastic containers which are produced by extrusion blow molding or by 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. This can be a single-stage stretch blow molding process in which a previously produced preform is stretch-blown immediately following its production to the desired plastic container. However, the plastic container can also be produced in a two-stage stretch blow molding process, in which the preform, after its production in a plastic injection molding process or in a flow molding process, is separated temporally and / or spatially from the desired plastic container, in particular to a plastic bottle, stretch blown. The invention is particularly advantageous in plastic containers, which are produced by the lost-neck process.

Fig. 1

zeigt eine teilweise geschnittene Ansicht eines supportringlosen Kunststoffbehälters, insbesondere einer Kunststoffflasche;

Fig. 2a - Fig. 2c

zeigen schematische Querschnitte durch eine Ringnut im Bereich einer Behälterschulter;

Fig. 3a und 4b

zeigen zwei weitere Querschnitte durch die Ringnut; und

Fig. 4

zeigt eine Ansicht eines Kunststoffbehälters, der nach einem Lost-Neck Verfahren hergestellt ist.

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.

Fig. 1

shows a partially sectioned view of a supportless plastic container, in particular a plastic bottle;

Fig. 2a - Fig. 2c

show schematic cross sections through an annular groove in the region of a container shoulder;

Fig. 3a and 4b

show two more cross sections through the annular groove; and

Fig. 4

shows a view of a plastic container, which is made by a lost-neck process.

Fig. 1 schematically shows 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 produced in a blow molding process, for example in an extrusion blow molding process from an extruded plastic hose or in a stretch blow molding process from a preform previously produced, for example, in an injection molding process or in a flow molding process, and consists of the plastic materials usually used for these processes, such as PE, for example. especially HDPE, PP, PET, PEN, PS, PLA, PA, as well as copolymers of these materials. It can be constructed in one or more layers.

The plastic container 1 has a container body 2 which is closed by 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 in the present embodiment are formed 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 with the in Fig. 1 illustrated plastic container 1, which is made in particular in a stretch blow molding from a supportringlose preform, formed on the container neck 5, a circumferential snap ring 7. 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 guarantee strip of the screw can not be levered over the snap ring 7.

In one of the adjacent to the threaded portions 6 region of the container neck 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 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.

Fig. 2a, 2b and 2c schematically show different cross-sectional contours of the annular groove 10. In this case, the cut surface runs approximately in the middle of 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 Ring groove 10 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. In the Fig. 2c shown abutment 16 are formed as notches-like depressions 13 which extend radially from the radial boundary surface 11 of the annular groove 10 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

At the in Fig. 3a and 3b illustrated embodiments, the abutment 16 for torque absorption in close proximity above and / or below the circumferential annular groove 10 are arranged. Fig. 3a shows to two projections 14 which protrude 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 above and / or below the annular groove 10 substantially radially from the boundary wall 8 of the container shoulder 4 inwards. 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 circumferential annular 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 circumferential annular groove 10 enables 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 circumferential annular groove 10 is arranged in the region of the structurally strong 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 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 annular groove 10 and / or above and / or below it.

Fig. 4 is a schematic representation of a plastic container, which is made by a lost-neck process. In turn, the plastic container carries the reference numeral 1. It is produced in a blow molding process, for example in an extrusion blown from an extruded plastic tube or in a stretch blown from a preform previously made for example in an injection molding or in a flow molding process and consists of the commonly used for these methods Plastic materials, 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 in Fig. 4 shown separated neck portion 30 is intended to indicate the production in the Lost-Neck process. At its outer wall close to the pouring opening 20, the plastic container is in turn equipped with fastening means 6 for the form-fitting 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, an annular groove 10 is formed in the adjacent outer wall 9 by the blow molding process, the cross section of which runs approximately perpendicular to an axis A of the plastic container 1. The dimensions and the special design of the annular groove 10 correspond to those of the basis of Fig. 1-3 for plastic bottles explained execution.

The invention provides, in particular, a supportringless plastic container 1 which has a container body 2 and a container neck 5 with a pouring opening 20. In the vicinity of the pouring opening 20 are in an outer wall 6 of the plastic container 1 fastening means 6 for the positive fixing of a closure intended. In a region between the container neck 5 and the container body 2, in a region close to the fastening means 6 for the form-fitting fixing of a closure part, a peripheral annular groove 10 is produced, which is produced in a blow molding process. Within the annular groove 10, at least one abutment 16 is formed for torque absorption. The invention is not limited to the specific variants described in the preceding exemplary embodiments, but also encompasses all equivalent embodiments resulting for the person skilled in the art from the description of the figures and the claims.

Claims (15)

Supportless plastic container with a container body (2) and a container neck (5) with a pouring opening (20) on the outer wall in the vicinity of the pouring opening (20) fastening means (6) are arranged for the positive fixing of a closure part, and one in the direction of the container body ( 2) to the container neck (5) adjoining region (4) in which a circumferential annular groove (10) is formed, which is produced in a blow molding, characterized in that within the annular groove (10) at least one abutment (16) for receiving torque is trained. Plastic container according to claim 1, characterized in that it is manufactured in a lost-neck process. Plastic container according to claim 1 or 2, characterized in that it is formed like a bottle. Plastic container according to one of the preceding claims, characterized in that the annular groove (10) having region (4) as a container neck (5) and the container body (2) connecting container shoulder is formed. Plastic container according to claim 4, characterized in that the annular 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. 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. 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. Plastic container according to one of the preceding claims, 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). Plastic container according to one of the preceding claims, 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. Plastic container according to one of the preceding claims, characterized in that in the vicinity of the circumferential annular groove (10), above and / or below the same in an adjacent outer wall (9) one or more abutment (16) are formed for receiving torque. Plastic container according to claim 10, characterized in that each abutment (16) as a projection (14) opposite the adjacent outer wall (9) is formed. Plastic container according to claim 10, characterized in that each abutment (16) is designed as a notch-like depression (15) in the adjacent outer wall (9). Plastic container according to claim 11 or 12, characterized in that each projection (14) or each notch-like depression (15) relative to the adjacent outer wall (9) has a radial extent (1) of about 1 mm to about 10 mm. Plastic container according to one of the preceding claims, characterized in that the abutments (16) are produced for torque absorption in a blowing process. Plastic container according to one of the preceding claims, characterized in that it is made of a supportringlose preform in a one- or two-stage stretch blow molding.

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