EP2925505A1

EP2925505A1 - Plastic container and method

Info

Publication number: EP2925505A1
Application number: EP13798574.3A
Authority: EP
Inventors: Johann Kuenz; Herbert Wohlgenannt
Original assignee: Alpla Werke Alwin Lehner GmbH and Co KG
Current assignee: Alpla Werke Alwin Lehner GmbH and Co KG
Priority date: 2012-11-27
Filing date: 2013-11-22
Publication date: 2015-10-07
Also published as: US20150251794A1; CH707260A1; WO2014082721A1; IN2015DN03755A; AR093604A1; BR112015011904A2; CN104995010A; MX2015006098A; CN104995010B; US20170066549A9

Abstract

The invention relates to an extrusion blow-molded plastic container (1) that has a container body, which is closed by a container base, and a container neck, which is provided with a pour opening. An inner wall of the container neck has at least one calibrated structuring. In order to produce a plastic container (1) with a container neck designed according to the invention, a portion of a single-layer or multilayer plastic tube which is extruded continuously or discontinuously from an extrusion head is introduced into a mold cavity of a blow molding tool. The tube section which can be found in the mold cavity is inflated into the plastic container so as to correspond to the mold cavity using a gas, which is blown into the tube section using positive pressure, by means of a calibrating blow mandrel (2), which is inserted into the tube through an opening in the blow molding tool, and the plastic container is cooled.

Description

PLASTIC CONTAINER AND METHOD

The invention relates to an extrusion-blown plastic container according to the preamble of claim 1. The invention also relates to a method for producing such a plastic container. 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, such as beverages, household products, care products, cosmetics, etc., now 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 the consumer's acceptance of plastic containers, in particular of plastic bottles. The production of plastic containers, in particular plastic bottles, for example made of polyethylene or polypropylene, often takes place in an extrusion blow molding process, in particular in a tubular blowing process. In this case, a plastic hose is extruded continuously or discontinuously with an extrusion head, introduced into the mold cavity of a blow molding tool, inflated by overpressure, cooled and demoulded. The inflation of a plastic hose section introduced into the blow mold cavity is usually carried out with a calibration blow mandrel, which is inserted through an opening in the blow mold cavity into the plastic hose section to be inflated. The Kalibrierblasdorn one hand has the task of introducing air into the plastic tube so that it is formed according to the Blasformkavität. On the other hand, the Kalibrierblasdorn also serves for defined Innenausformung (calibration) of the neck of the

Hose section inflated plastic container on which the pouring opening is provided. For this purpose, the Kalibrierblasdorn is retracted through the opening of the closed Blasformwerkzeugs in the tube section. In doing so, excess art Substance material axially displaced and so set the inner diameter of the usually having a cylindrical inner wall having neck with the Ausgiessöffhung.

Known, produced by extrusion blow molding plastic containers have a closure which is fixed in a form-fitting manner on fastening means which are formed on the outer wall of the container neck. The fastening means may be formed, for example, as an external thread, as external thread sections, as guides of a bayonet closure, or as a snap ring. In this case, the fastening means may be formed projecting relative to the outer wall of the container neck or as corresponding grooves and depressions in the outer wall of the container. The attachment means may also be formed as a combination of protrusions and recesses. The closure is provided with correspondingly formed elements in order to enable a positive cooperation. The known closures overlap and overhang the neck of the plastic container. As a result, the plastic container provided with the closure has a greater height than the plastic container alone. Also, the plastic containers provided with a closure always have a clearly visible dividing line between the closure and the plastic container, which is often undesirable. In many cases, the closures are also different in color from the plastic container. However, if it is desired that the closure and the plastic container form a unit in color, problems arise on the one hand alone from the mostly different materials for the plastic container on the one hand and for the closure on the other hand. Often, the shades of the plastic container and the closure do not match exactly. Even if the color tone is largely the same, the usually different surface finish of the closure and the plastic container can lead to different color impressions in the observer. The different surface finish is a consequence of the different materials, but also of the different manufacturing processes. For example, the plastic container produced in an extrusion blown process can have a glossy surface, while the closure produced mostly in an injection molding process can have a matt surface. Thus, originating from different production batches plastic containers and / or closures may have slightly different shades. This is sometimes unacceptable for the customers of the containers with closures. The Therefore, the dividing line and the differences in color between the closure and the plastic container can also impair the design freedom with regard to the container design. The greater height of the container provided with the closure increases the space requirement.

It is therefore an object of the present invention to remedy these disadvantages of the extrusion-blown plastic containers of the prior art. A plastic container should be modified so that the assembly of a closure is possible without or only with slight change in the height of the plastic container. A dividing line between the closure and the plastic container should be avoided as well as aesthetic problems with regard to color deviations between the plastic container and the closure. It is to be created a plastic container that can be produced without major process changes in the extrusion blow. The production cycles should be able to be largely maintained.

The solution of these objects consists in an extrusion-blown plastic container, which has the features listed in claim 1. An inventive extrusion blow molding process is the subject of the independent method claim. Further developments and / or advantageous embodiments of the invention are the subject of dependent device or method claims.

The invention provides an extrusion-blown plastic container which has a container body closed with a container bottom and a container neck adjoining the container body and provided with a pouring opening. An inner wall of the container neck has at least one calibrated structuring, which extends at least in regions over a circumference of the inner wall. The calibrated structuring is limited towards the container body by accumulation of material. The material accumulation is formed as a collar extending at least partially along the circumference of the inner wall and substantially transversely to a central axis of the container neck.

Under calibrated is to be understood that the structuring can be reproducibly made with predetermined dimensions. The tolerances of the mass of the calibrated structuring can be material-dependent within the usual tolerances achievable in the extrusion blow-molding process. Since, in order to form the calibrated structuring, additional plastic material is introduced from the lost tube section adjoining the pouring opening through the pouring opening into the container neck, the tolerances can result, for example, from cooling processes and / or creeping processes of the plastic. The excess plastic material not required for the formation of the calibrated structuring limits the accumulation of material formed as a collar to the calibrated structuring. The collar extends in the direction of the central axis of the container neck, ie into the interior of the container neck. A limited by the collar opening is usually smaller than the Ausgiessöffhung. Here, the calibrated structuring and the collar are integrally formed with the container neck. Also, a calibration tool is needed to form the calibrated pattern, wherein the shape of the structuring can be determined by the tool. Ideally, the calibration tool is integrated as a calibration section on the calibration bladder, which is inserted into a plastic tube section inserted in a mold cavity. By calibrated structuring is meant a structural element which is positively or negatively formed on or in the inner wall of the container neck and which can prevent the calibration tool from being removed from the mold cavity in the opposite direction of movement. The calibrated structuring may thus be formed as a projection or as an undercut with respect to the inner wall of the container neck. An undercut jumps back to the unstructured course of the inner wall of the container neck by a predetermined amount, this measure can be greater than or equal to 0.25 mm. If the calibrated structuring is designed as a projection, it projects beyond the unstructured course of the inner wall by a predetermined amount in the direction of a central axis of the container neck, wherein the predetermined dimension can be greater than or equal to 0.25 mm. The predetermined mass may be greater than 0.5 mm, preferably greater than 0.7 mm, depending on the neck diameter. In general, the Kalibrierblasdorn or the calibration tool is retracted by an exclusively translational movement in the mold cavity. Due to the calibrated structuring, an exclusively translatory removal of the calibration bladder from the mold cavity can be prevented. In order nevertheless to allow a removal of the Kalibrierblasdorns or a Kalibrierwerkzeugs, it may be necessary, for example, the Kalibrierblasdorn or the calibration tool by means of a combination of translational and to remove rotational movement from the plastic container. In an alternative variant of the method, the calibration bladder or the calibration tool is removed from the mold cavity together with the plastic container connected to it, and the plastic container is then removed from the Kablibrier blasting mandrel or the calibration tool by utilizing the elasticity of the plastic. In this embodiment, the calibration tool, or the Kalibrierbleßdorn, with respect to its outer shape is fixed or rigid. Furthermore, the calibrating tool or the calibrating section of the calibrating bladder mandrel can be made variable in its shape in order to be able to remove the calibrating tool or the calibrating bladder mandrel from the plastic container after the calibrated structuring has been formed.

By having the plastic container on the inner wall of the container neck at least one calibrated structuring, the conditions for the installation of an inner closure are given. The at least partially circumscribed calibrated structuring in this case has a depth sufficient to accommodate the inner closure and to keep it safe in the usual drop tests. Due to the possibility of attaching an inner closure, the overall height of the plastic container provided with the closure remains substantially limited to the height of the container itself. The space requirement for the containers provided with closures is thereby reduced. The inner closure contributes not or only slightly to the overall height and is virtually invisible in a side view. As a result, the dividing line between the closure and the container, which is usually clearly visible in the case of plastic containers with closure, is eliminated. Color differences caused by different shades or different surface textures play practically no role because of the invisible closure in the side view. As a result, the effort for the color match of the plastic container and the closure can be reduced. The closure can also be a punctiform design element, ie a color coordinated design element with respect to the plastic container, in the overall appearance of the plastic packaging. Hiebei the plastic packaging usually consists of the plastic container, the closure and a label.

In general, the described type of closures are tipping closures which, when flush with the pouring opening, remove fabric container to prevent stored substance. Here, in a closed position, a central axis of the closure and the central axis of the container neck are generally parallel. In order to allow removal of the stored material, the tilting shutter is moved to an open position, usually by the center axis of the tilting shutter is inclined relative to the central axis of the container neck and correspondingly enclose the two central axes an acute angle. Advantageously, one of the Ausgießöffhung facing top of the collar, which is formed from the excess material, calibrated. Thus, this calibrated top can form a defined stop surface for the normally injection molded closure for its closed position and open position. One of the top of the collar corresponding shape may be formed in the Kalibrierblasdorn, respectively the calibration tool. When the hose in the tool is pressed against the inner wall of the mold halves by the gas pressure, this pressure can also be used to press the accumulation of material against the form corresponding to the upper side in the calibrating tool in order to form the calibrated upper side of the collar. Accordingly, the collar can be unstructured on an underside facing away from the ejection opening in the sense that the shape of the underside is shaped by the gas pressure.

The plastic container does not have to be designed such that an axis of the container body and the center axis of the container neck are congruent or extend in parallel. Rather, the central axis of the container body and the central axis of the container neck can enclose an acute angle with each other, which can be up to 10 °, advantageously up to 20 °, preferably up to 25 °. By suitable manufacturing processes even an acute angle of up to about 45 ° is possible. In such an arrangement, a visible upper surface of the inner closure may be used as a carrier of a logo.

A contour of the inner wall and a contour of the outer wall of the container neck of the extrusion-blown plastic container are not formed corresponding to one another. In this case, the contour of the inner wall may be different from the contour of the outer wall. For example, the inner wall can have an internal thread and the outer wall can be designed as a circular cylinder with a plane, that is to say substantially unstructured, unimodal lateral surface. Also, the outdoor be formed curved wall and the inner wall have at least one undercut for receiving the closure.

The at least one calibrated structuring on the inner wall of the container neck can be designed differently and thereby also allows the assembly of different types of inner closures. The calibrated structures may be configured to seal the closure at any position along the container neck. In one embodiment of the invention, the extrusion-blown plastic container in the inner wall of its container neck on a single, annular circumferential undercut, which extends over 3/5 to 8/9 of the axial length of the container neck. The depth of the undercut against the inner wall is dependent on the cross section of the container neck and the requirements of a drop test from a predetermined height, the unsupported must survive the sealed plastic container. The calibrated structuring can be designed in such a way that it is possible to assemble a disk-shaped tilting closure. The predetermined amount by which the calibrated patterning projects or recedes from the inner wall of the container neck may be up to about 1.6 mm per side or even more depending on the container neck diameter, container size, and material. It turns out, however, that for a container neck of 38 mm diameter, an article volume of approximately 400 ml and a drop height of 120 cm in conjunction with a disk-shaped closure and using a typical HDPE material, a size of 0.72 mm is calibrated for the calibrated Structuring is sufficient.

The contour of the calibrated structure of the inner wall of the container neck of the extrusion-blown plastic container is formed on the side contour of the disk-like

Tilting closure adapted. For example, the calibrated pattern has a contour that is similar to a portion of a torus surface. This means that the axial and radial radii of curvature are different from each other. The torus surface can be formed on an undercut of the inner wall or on a projection opposite the inner wall. In one embodiment variant of the plastic container, which may prove expedient, in particular for larger opening diameters, the calibrated structuring of the container neck has a contour which resembles a section of a spherical surface. This means that the axial and the radial radius of curvature are the same size. A suitable for this embodiment tilt lock then corresponds to a cut from a ball disc. Again, the calibrated structuring may be formed as an undercut or as a projection, each with a spherical surface contour.

The calibrated structuring of the inner wall of the container neck of the extrusion-blown plastic container can merge, at its outlet facing the container body, into an at least partially encircling collar, which has a radial overhang with respect to the inner wall. The at least partially encircling collar can serve as a support or abutment for the disc-shaped Kippverschluss. The collar can also be designed as an annular shoulder. So that the tiltability is ensured, the disk-shaped tilt lock on a support surface which extends approximately over half of its circumference approximately parallel to a top surface of the tilt lock and approximately from half obliquely to the top surface. In an alternative embodiment of the extrusion-blown plastic container, the annular at least partially circumferential shoulder forms a support surface, wherein the support surface and a central axis of the container neck form an acute angle. In this embodiment variant of the container neck, the disc-shaped tilting closure can be cylindrical. So that its orientation is ensured approximately perpendicular to the container axis, in the inner wall of the container neck also two mutually preferably diametrically opposite support projections may be provided, which engage in lateral recesses or cuts in the support surface of the disc-shaped tilt lock. In addition, the container neck and the closure can be designed such that even in the open position, the closure seals at predetermined locations within the container neck, so that the container contents can leave the plastic container exclusively at a predetermined location.

The radial projection of the at least partially encircling annular shoulder with respect to the inner wall of the container neck is about 0.5 mm to 2.5 mm, depending on the container size.

In a further embodiment variant of the extrusion-blown plastic container, the at least one calibrated structuring of the inner wall of the container neck is used as a at least one receiving groove designed for a bayonet lock. Because of the better fixation of a closure two or more distributed over the circumference of the inner wall receiving grooves are formed for a bayonet in the inner wall of the container neck.

Another embodiment of the extrusion-blown plastic container has a container neck, in which the at least one calibrated structuring of the inner wall of the container neck is designed as an internal thread. Thread closures are well known. The over a relatively large extent extending positive engagement between the co-operating threads of the internal thread in the container neck and the external thread on a screw cap allow a reliable hold, which ensures the fulfillment of the required drop tests. The calibrated structures for the internal thread are created with the aid of the calibration spike. The demolding of the Kalibrierblasdorns is usually done by train. If the elasticity of the material used for the plastic container is too low for a strain relief, the calibration mandrel can also be removed for demoulding.

At the transition of the container neck of the extrusion-blown plastic container into the container body, an at least partially circumferential groove may be arranged in an outer wall of the container neck. Through the groove formed at the transition from the container neck into the container body a narrowing of the wall thickness, which limits the calibration of the container neck and the formation of the at least one undercut a displacement of the plastic material in the subsequent container body. To produce a plastic container with a container neck formed according to the invention, a section of a single or multilayer plastic tube extruded continuously or discontinuously from an extrusion head is introduced into a mold cavity of a blow molding tool. The tube section located in the mold cavity is inflated and cooled by means of a Kalibrierblasdorns driven into the tube by an opening in the blow mold into the plastic container by means of a gas injected with excess pressure in accordance with the mold cavity. In this case, a container neck of the corresponding portion of the plastic tube is calibrated. When retracting the Kalibrierblasdorn in the hose section is plastic material of a the produced container neck displaced upstream lost portion of the plastic tube in the container neck. By the retracted Kalibrierblasdorn at least one calibrated structuring is formed in an inner wall of the container neck, the shape of which is determined by an outer contour of a calibration section of the Kalibrierblasdorns. The calibrated structuring can be formed as an undercut or as a projection. The finished molded plastic container is finally removed from the mold.

In order for at least one calibrated structuring to be able to be produced in or on the inner wall of the container neck, the calibrating bladder mandrel must have a calibrating section which, for example, has an oversize relative to a diameter of a cylindrical inner section of the container neck. Plastic material is displaced from the container neck into the container body through this diameter-larger area of the calibration bladder. The inner wall of the container neck may be formed in addition to a circular contour with an oval or square contour or a combination of round and square, the process described is mutatis mutandis applicable. So that now enough plastic material remains in the container neck to ensure the required minimum wall thickness, plastic material is displaced from a container neck the neck before stored lost portion of the extruded plastic tube into the container neck when retracting the Kalibrierblasdorns in the cavity located in the mold cavity. The plastic material from the lost portion, which is sometimes referred to as a neck piece, compensates for the plastic material displaced from the neck portion. Thus, enough material is again available and the required minimum wall thicknesses in the container neck can be maintained. The lost portion of the extruded plastic tube is usually automatically separated from the container neck at the end of the blowing / calibration process. By displacing plastic material from the lost portion into the container neck as the calibration spike retracts, the inner wall of the container neck can be provided for the first time with one or more calibrated structurings which are designed such that, for example, an internal closure can be mounted.

In a variant of the process management, an at least partially circumferential groove can be formed at a transition from the container neck to the container body in a wall of the plastic container. Through this groove, at the transition from the container neck in the container body creates a narrowing of the wall thickness. This narrowing limits the displacement of the plastic material in the subsequent container body during calibration of the container neck and in the formation of the at least one structuring. By the constriction is chosen such that less plastic material can be displaced from the container neck into the container body, as is simultaneously tracked from the lost portion of the plastic tube in the container neck, even more complex structuring, such as successively arranged threads, in the inner wall of the container neck through an exclusively translational movement of the Kalibrierblasdorns are generated with the integrated Kalibrierabschnitt. Since the displacement of the plastic material is hindered by the constriction, it is locally compressed for a short time, in order then to expand again into the voids located between the larger diameter areas of the calibration section.

In a further variant of the process management, an at least partially encircling annular shoulder can be formed at a transition from the container neck to the container body, preferably at a transition from the calibrated structuring to the container body, which has a radial projection with respect to the inner wall of the container neck. The at least partially circumferential annular shoulder is preferably formed with a radial projection of about 0.5 mm to 2.5 mm. It can serve as a support surface or as an abutment when mounting a disk-shaped Kippverschlusses. So that the tiltability is ensured, the disk-shaped tilt lock is formed with a support surface which extends approximately over half of its circumference substantially parallel to a top surface of the tilt lock and approximately from half obliquely to the top surface.

A further embodiment variant of the method according to the invention can provide that the annular at least partially circumferential shoulder is formed in such a way that the shoulder and a central axis of the container neck enclose an acute angle. Now, the disk-shaped tilt lock can be made cylindrical. Of course, the outer contour of the Kippverschlusses have any outer contour. It may for example be oval, triangular, quadrangular or polygonal. So that its orientation is ensured approximately perpendicular to the container axis, in the inner wall of the container neck also two mutually preferably diametrically opposite support projections are formed, which engage in lateral recesses or cuts in the support surface of the disk-shaped tilt lock.

The contour of the calibrated structuring of the inner wall of the container neck of the extrusion-blown plastic container is adapted during calibration to the side contour of the disk-shaped tilt closure. For example, the calibrated structuring of the container neck may be formed with a contour that is similar to a portion of a torus surface. This means that the axial and the radial radius of curvature of the structuring are different from each other. In one embodiment, the calibrated structuring of the inner surface of the container neck can be provided with a contour that is similar to a section of a spherical surface. This means that the axial and the radial radius of curvature are the same size. A suitable for this embodiment tilt lock then corresponds to a cut from a ball disc. Also, a contour of the inner wall and a contour of the inner wall opposite the outer wall can not be formed corresponding to each other, so that, for example, the outer contour is flat and the inner contour has at least one calibrated structuring.

In alternative variants of the method, the inner surface of the container neck can be provided with one or more mounting grooves for a bayonet closure. Finally, an internal thread can be created in the inner wall of the container neck.

It is clear to a person skilled in the art that the individual features, insofar as they are not mutually exclusive, can be combined with one another in any desired manner, in order thus to arrive at further embodiments of the invention.

Further advantages and features of the invention will become apparent from the following description of the method with reference to the schematic drawings not to scale.

Fig. 1 shows a half-side, axially sectional view of a retracted in a blow mold Kalibrierblasdorns; FIG. 2 shows an axial section of a container neck with a plate-shaped tilting closure in the closed position; FIG.

Fig. 3 shows the plate-shaped tilting lock of Figure 2 in the open position.

FIG. 4 shows a variant of a calibration blast mandrel inserted into a blow molding tool in a representation analogous to FIG. 1; FIG.

FIG. 5 shows a further axial section of a container neck with a disc-shaped tilting closure in an open position; FIG. and

Fig. 6 shows the known from Figure 5 representation with a tilt lock in a closed position.

In the following description of the figures, the same reference numerals designate identical components.

1 shows an axial section of a half side of a calibrating blow mandrel inserted into a mold cavity of a blow molding tool for producing a plastic container, which carries the reference numeral 2 in its entirety. The blow molding tool, of which only an upper, in particular for the formation of a container neck formed portion is shown, bears the reference numeral 3. The mold cavity is provided with the reference numeral 33. In the space between the Kalibrierblasdorn 2 and the blow mold 3, a container neck 11 is provided with a provided with the reference numeral 1 plastic container. At the container neck 11, a container body 12 connects. For the sake of clarity, it has been omitted to provide the cut container neck 11 and the container body 12 with hatching.

Fig. 1 shows the Kalibrierblasdorn 2 in its end position in which a stop 21 of the Kalibrierblasdorns 2 abuts against an abutment 31 of the blow mold 3. By the stop 21 and the abutment 31 is ensured in a simple mechanical manner that the Kalibrierblasdorn 2 is always retracted equal to the mold cavity 33. The calibration bladder 2 has a calibration section 22, the outer contour of which is shown in FIG. Asked embodiment is formed curved approximately spherical surface. Instead of a spherical surface shape, the calibrating section 22 could also have the shape of a torus surface. The calibration section 22 is adjoined by a nozzle part 24, via which a gas is injected with overpressure in order to inflate an extruded plastic hose section in the mold cavity 33 according to the mold cavity 33 to the plastic container 1. Between the stop 21 and the calibration section 22 a Nachdrückabschnitt 25 is arranged, whose function will be explained in more detail below. The blow molding tool 3 has an input section 35 which ends at an edge projection 32. This edge projection 32 is formed in the plastic container 1 as a constriction. In a successor unit, the container neck 11 is then essentially along its deepest constriction, which later forms a neck edge 16 of the container neck 11 and is shown here as a dotted line, from a section of the container adjacent to the container neck 11 and located above the neck edge 16 Plastic hose 18 separated. This portion of the plastic tube 18, which is located between the inlet portion 35 of the blow molding 3 and the Nachdrückabschnitt 25 of the caliber rierblasdorns 2, is referred to as a lost tube section or as a neck.

When retracting the Kalibrierblasdorns 2 in the enclosed by the blow molding 3 tube section of plastic material from the lost tube section 18 and the container neck 11 is displaced in the direction of the container body 12 of the calibration section 22 leading edge 23 and the calibration 22 itself. The displaced plastic material collects at the transition from the container neck 11 to the container body 12 and forms there an at least partially encircling collar or an at least partially encircling annular shoulder 14. The Nachdrückabschnitt 25 of Kalibrierblasdorns 2 displaces further plastic material from the lost tube section 18 in the neck portion 11, so that On the inner wall 13 according to the outer contour of the calibration section 22 a calibrated structuring is formed, which is formed according to the illustrated embodiment as an undercut 19. The calibrated undercut 19 formed in the inner wall 13 has, for example, a spherical-surface-shaped or a torus-shaped contour. In support of the Forming of the at least partially encircling annular shoulder 14 may be formed in an inner wall opposite the inner wall of the container neck 11, at the transition to the container body 12 an at least partially annular groove 15, wherein a remaining part of the outer wall as a straight flat Kreiszy- linder, ie without sink marks , is trained. Thus, a contour of the outer wall of a contour of the inner wall 13 is so different that these two contours do not correspond with each other. The groove 15 generates at the transition from the container neck 11 to the container body 12, a wall thickness restriction, which opposes the displacement of the plastic material from the container neck 11 into the container body 12 a resistance. As a result, the shape of the at least partially encircling annular shoulder 14 and the shape of the calibrated undercut 19 are favored. The calibrated structuring in the form of an undercut 19 is limited by the annular shoulder 14. The annular shoulder 14 is formed from the plastic which has been displaced from the section of the plastic tube 18 located above the neck edge 16 into the container neck 11 through a pouring opening at the neck edge 16 and after the design of the calibrated pattern 19 is excessive. The excess plastic forms a build-up of material 100 which is deformed by the gas pressure needed to inflate the tube section loaded in a blow mold 3. Here, on the annular shoulder 14, a Ausgießöf hung facing calibrated top 36 is formed, which corresponds to a formed in the Kalibrierabschnitt 22 corresponding shape 37, which is here designed disk-shaped. This calibrated top 36 can be used as a stopper for all types of closures. One of the top 36 opposite and facing away from the pouring bottom 38 is formed in the present embodiment by the gas pressure and is thus unstructured.

The calibrated structuring in the form of an undercut 19 produced in the inner wall 13 of the container neck 11 has a depth greater than or equal to 0.25 mm in relation to an unstructured contour of the inner wall 13. In an expedient embodiment, the undercut 19 extends over about 3/5 to about 8/9 of the axial length of the container neck 11; their depth is greater than about 0.5 mm, preferably greater than about 0.7 mm, depending on the size of the container neck or container neck diameter. When choosing the depth of the undercut or when choosing the height of an as Advantageously trained calibrated structuring, the size of the container neck 11, as well as relevant customer requirements, such as the height of fall, the choice of materials, etc. to be considered. The at least partially encircling annular shoulder 14, which may also be formed as a closed ring, facing the inner wall 13 of the container neck 11 has a radial projection of about 0.5 mm to about 2.5 mm. The thus formed container neck 11 is prepared for receiving an inner closure, which may be formed as a plate-shaped Kippverschluss.

2 and 3 show a plate-shaped tilting lock 5 mounted in the container neck 11 in the closed (FIG. 2) and in the open position (FIG. 3). The plate-shaped tilting closure 5 has a support surface 51 with a first support section 52, which extends approximately over half of its circumferential extent approximately parallel to a cover surface 55 of the tilt lock 5. An adjoining second support portion 53 extends obliquely inclined to the top surface 55. The plate-shaped tilt lock 5 is supported on the annular peripheral shoulder 14 from. In the closed position, its first support section 52 extending parallel to the cover surface 55 lies on the annular peripheral shoulder 14 (FIG. 2). In the open position, the obliquely extending second support portion 53 rests on the annular peripheral shoulder 14 (FIG. 3). On the inner wall 13 of the container neck 11 also two preferably diametrically opposed calibrated undercuts 19 may be formed as support projections 17 which engage in lateral recesses 54 and cuts in the support surface 51 of the plate-shaped or disc-shaped tilt lock 5. The contour of the formed in the inner wall 13 undercut 19 of the container neck 11 of the extrusion-blown plastic container 1 is adjusted during calibration to the side contour of the disk-like Kippverschlusses 5.

In an alternative embodiment variant of the container neck 11, which is not shown in more detail, the annular circumferential shoulder 14, which forms a bearing surface for the closure, can also be designed such that the bearing surface and a central axis of the container neck form an acute angle. With such a design of the container neck 11, the plate-shaped tilting closure 5 can have an overall cylindrical shape with a support surface extending essentially parallel to the cover surface 55. The tiltability of the plate-shaped closure 5 is tilted by the Forming the annular peripheral shoulder 14 ensures. In order that the plate-shaped tilting closure 5 is aligned approximately perpendicularly to the container axis in the closed position, two preferably diametrically opposite support projections 17 can be formed in the inner wall 13 of the container neck 11, which in lateral recesses or incisions 54 in the support surface of the disc-shaped Tilt lock 5 intervene.

FIG. 4 shows a variant of a calibration bladder, which in turn bears the reference numeral 2 in its entirety, in a representation analogous to FIG. The same parts therefore bear the same reference numerals as in Fig. 1. In contrast to the explained with reference to FIG. 1 exemplary embodiment, the calibration section 22 of the Kalibrierblasdorns 2 threaded projections 27 on. The thread projections 27 of the Kalibrierblasdorns 2 form in the inner wall 13 of the container neck 11 from an undercut 19, which has the shape of an internal thread. Again, the push-back section 25 of the calibration bladed mandrel 2 causes plastic material to be displaced from the lost tube section 18 into the container neck 11 when the calibration bladder 2 is moved in exclusively translationally. A restriction created by the groove 15 in the outer wall of the container neck 11 at the transition from the container neck 11 to the container body 12 obstructs the displacement of the plastic material from the container neck 11 into the container body 12. Thus, more plastic material is displaced from the lost portion 18 into the container neck 11 Plastic material from the container neck 11 is displaced into the container body 12. This results in the container neck 11 to a short-term local compression of the plastic material, which can then expand back into the free spaces between the turns of the formed on the inner wall 13 internal thread. In addition, at the transition from the container neck 11 to the container body 12 again an annular at least partially circumferential shoulder 14 is generated.

Similar to FIGS. 2 and 3, FIGS. 5 and 6 show a longitudinal section through the container neck 11 with the container body 12 adjoining the container neck 11, each with a closure 5 mounted in the container neck 11 in its respective end position. For reasons of clarity hatching was omitted in both figures. Fig. 5 shows the disc-shaped closure 5 in its open position, while Fig. 6 shows the disc-shaped closure 5 in its closed position. In contrast to the versions The exemplary embodiments according to FIGS. 2 and 3 have dispensed with the support projections in the calibrated structuring and the lateral notches in the support surface 51 in the present exemplary embodiment. Correspondingly, the first support section 52, which extends substantially parallel to the cover surface 55, adjoins the second support section 53, which extends obliquely inclined to the cover surface 55. Between the top surface 55 and the support surface 51, a closure side wall 57 extends circumferentially, the outer wall 58 facing the hollow-spherical undercut 19 being designed as a ball. Here, the undercut 19 and the outer wall 58 of the closure side wall 57 are corresponding. Furthermore, the closure 5 in the closure side wall 57 has a pouring opening 56. Opposite the pouring opening 56, a finger recess 54 is formed in the top surface of the closure 5, which indicates to the person using which position the closure has to be pressed in order to move the closure 5 to shift to the open position shown in Fig. 5. In this case, stockpiled material can be taken out through the pouring opening 58 in the container body 12. In this open position, a central axis II-II of the closure 5 is obliquely inclined with respect to a central axis II of the container neck 11. In this open position, the second support section 53 is defined on the calibrated upper side 36 of an annular circumferential shoulder 14 formed from a material accumulation 100. The underside 38, which is unstructured, faces the calibrated upper side 36 opposite the container body 12. The calibrated upper surface 36 extends substantially transversely to the central axis II of the container neck 11. The calibrated upper surface 36 adjoins the calibrated structuring formed in the inner wall 13 of the container neck 11 in the form of a hollow-spherical undercut 19. An outer wall 20 opposite the inner wall 13 is referred to as straight circular cylinder formed, which is due to the excess of plastic, which ultimately forms the accumulation of material 100 and thus the circumferential annular shoulder 14, without default and not with a contour of the inner wall 13 is corresponding. In the illustrated in Fig. 1 groove between the container neck 11 and the container body 12 has been omitted in the two present embodiments.

Fig. 6 shows the known from Fig. 5 arrangement in the closed position. Here, the first bearing portion 52 is predetermined at the top 36 of the circumferential annular shoulder 14. In this position, the pouring opening 36 is replaced by the calibrated structure. closed in the form of a hollow-spherical undercut 19. It goes without saying that in this position the calibrated structuring in the form of a hollow-spherical undercut 19 and the spherical closure side wall 57 cooperate in such a way that no material stored in the container body 12 enters the environment. In the closed position in the present embodiment, the top surface 55 of the closure 5 and the neck edge 16 are flush with each other. Further, the central axis II of the container neck 11 and the central axis II-II of the closure 5 coincide.

The production of a calibrated structuring 19 of the inner wall 13 of the container neck 11 has been explained with reference to FIGS. 1 and 4, which can be designed as a single large-area undercut having a spherical-surface-shaped or torus-shaped contour (FIG. 1) or by an internal threading in FIG Inner wall 13 (Fig. 4) is formed. In further embodiments of the invention, one or more calibrated structurings can be designed in the form of one or more mounting grooves for a bayonet closure. Furthermore, the calibrated patterns may also be one or more circumferentially spaced images for one or more

Schnappwülste be formed. This allows, for example, the installation of a known multi-part tilting closure, which can be arranged invisibly in the interior of the container neck, however, in contrast to the prior art.

In a method for producing a plastic container with a container neck formed according to the invention, in a first method step, a section of a plastic tube which is extruded continuously or discontinuously by an extrusion head is introduced into a mold cavity of a blow molding tool. In a second process step, which is located in the mold cavity

Hose section inflated by means of a retracted by an opening in the blow mold into the tube Kalibrierblasdorns inflated by an over-pressure gas according to the mold cavity to the plastic container and cooled. In this case, a container neck of the corresponding portion of the plastic tube is calibrated. When performing the second process step is when retracting the Kalibrierble Dorn in the

Hose section plastic material displaced from a the container neck produced upstream lost portion of the plastic tube in the container neck. By the retracted Kalibrierblasdorn at least one calibrated structuring is formed in or on an inner wall of the container neck, the shape of which is determined by an outer contour of a calibration section of the Kalibrierblasdorns. The calibrated structuring may be formed as an undercut receding from the inner wall by a predetermined amount, or as a projection protruding from the inner wall of the container neck by a predetermined amount. In a third process step, the finished molded plastic container is finally removed from the mold.

Claims

claims

1. Extrusion-blown plastic container with a container body which is closed with a container bottom, and with a container neck to the container neck, which is provided with a Ausgiessöffhung, characterized in that an inner wall of the container neck has at least one calibrated structuring, at least partially over extends a circumference of the inner wall, wherein the calibrated structuring is limited in the direction of the container body of a material accumulation, wherein the accumulation of material is formed as a at least partially along the circumference of the inner wall and substantially transverse to a central axis of the container neck extending collar.

2. Extrusionsgeblasener plastic container according to claim 1, characterized in that the collar is formed substantially from a plastic material, which is displaced from a subsequent to the Ausgießöffhung lost tube section.

3. Extrusionsgeblasener plastic container according to one of the preceding claims, characterized in that the collar is calibrated at one of the Ausgießöffhung facing top.

4. Extrusion-blown plastic container according to one of the preceding claims, characterized in that an outer wall, which is opposite to the inner wall provided with the at least one calibrated structuring, has a contour deviating from the contour of the inner wall.

5. Extrusionsgeblasener plastic container according to claim 4, characterized in that the outer wall is formed substantially unstructured.

6. Extrusionsgeblasener plastic container according to one of the preceding claims, characterized in that the calibrated structuring over an unstructured course of the inner wall has a radial height or depth which is greater than or equal to 0.25 mm.

7. Extrusionsgeblasener plastic container according to claim 6, characterized in that the calibrated structuring over an unstructured course of the inner wall has a radial height or depth which is greater than 0.5 mm, preferably greater than 0.7 mm.

8. extrusion blown plastic container according to one of the preceding claims, characterized in that the calibrated structuring has a contour which is similar to a portion of a Torusfläche.

9. Extrusion-blown plastic container according to one of claims 1 to 7,

characterized in that the calibrated patterning has a contour that is similar to a portion of a spherical surface.

10. Extrusion-blown plastic container according to one of the preceding claims, characterized in that the calibrated structuring of the inner wall of the container neck is formed as a single, annular circumferential undercut which extends over 3/5 to 8/9 of an axial length of the container neck.

11. extrusion blown plastic container according to claim 9, characterized in that the extension of the collar of the structured calibration transverse to the central axis of the container neck is 0.5 mm to 2.5 mm.

12. Extrusion-blown plastic container according to one of claims 2 to 11,

characterized in that the top of the collar forms a support surface, wherein the support surface and the central axis of the container neck include an acute angle.

13. Extrusion-blown plastic container according to one of claims 1 to 7, characterized in that the at least one undercut in the inner wall of the container neck is designed as at least one receiving groove for a bayonet closure.

14. Extrusionsgeblasener plastic container according to claim 13, characterized in that in the inner wall of the container neck two or more distributed over the circumference of the inner wall Aufhahmenuten are formed for a bayonet closure.

15. Extrusion-blown plastic container according to one of claims 1 to 7,

characterized in that the at least one undercut is formed in the inner wall of the container neck as an internal thread.

16. Extrusion-blown plastic container according to one of the preceding claims, characterized in that at the transition of the container neck in the container body in an outer wall of the container neck an at least partially circumferential groove is arranged.

17. A method for producing a plastic container according to any one of claims 1 to 16 in an extrusion blown process in which a portion of a continuously or discontinuously extruded from an extrusion head, single or multilayer plastic tube introduced into a mold cavity of a blow mold, by means of an opening in the blow mold in the tube retracted Kalibrierblasdorns is inflated and cooled by an over-pressure gas blown according to the mold cavity to the plastic container, wherein a container neck corresponding portion of the plastic tube is calibrated, and the plastic container is demolded, characterized in that during the retraction of the Kalibrierblasdorn plastic material of a lost portion of the plastic tube upstream of the container neck produced displaced by the Ausgießöff in the container neck and in the inner wall of the container neck w at least one calibrated structuring according to an outer contour of a calibration section of the Kalibrierblasdorns formed and in that a material accumulation delimiting the calibrated structuring in the direction of the container body is formed from the plastic material, the accumulation of material being formed as a collar which extends at least partially along the circumference of the inner wall and substantially transversely to a central axis of the container neck.

A method according to claim 17, characterized in that the collar is calibrated at one of the Ausgießöffhung facing top and that the collar is unstructured at a side facing away from the Ausgießöffhung bottom.

A method according to claim 17 or 18, characterized in that a contour of the inner wall and a contour of the inner wall opposite the outer wall are not formed corresponding to each other.

Method according to one of claims 17 to 19, characterized in that an at least partially circumferential groove is formed at a transition from the container neck to the container body in an outer wall of the plastic container.