Apparatus and method for molding bottle preforms

Abstract

A method for molding one or more bottle preforms, wherein molten plastic is injected into at least one molding cavity (5); and wherein, by means of a suction device (102), air is extracted from at least one molding cavity (5) through at least one channel (2, 2', 201, 202) so that air passes from at least one molding cavity (5) to the outside of the molding device (1, 1'); and an apparatus and a device for performing this method.

Description

Field of the Invention

[0001] The field to which the present invention relates is the moulding of plastic bottle preforms, in particular plastic bottle preforms made of thermoplastic material, such as PET.

[0002] The invention relates in particular to an apparatus and a device for moulding bottle preforms and a method for moulding bottle preforms. Background Art

[0003] Plastic bottle preform (particularly the plastic bottle preform made of thermoplastic material) is usually manufactured by injection molding or injection compression molding method.In such method, a given amount of molten thermoplastic polymer material is injected into the mold with high pressure, which gives the shape of the preform.

[0004] The mold is designed with ventilation passages to evacuate gases (particularly air and volatile compounds generated by polymer degradation) from the molding cavity.

[0005] Known molding apparatus and methods provide for gas to be expelled from the molding cavity during polymer injection only through the molten polymer entering the molding cavity.

[0006] However, often the gases in the moulding cavity are not sufficiently expelled, in particular they are only partially expelled.

[0007] Therefore, disadvantageously, air is trapped and the mold cavity is not filled, and unacceptable defects such as burrs, burns, and flow lines may occur on the preform. Such defects are more obvious and occur more frequently as the injection speed increases.

[0008] Furthermore, disadvantageously, volatile compounds condense on the surfaces defining the ventilation passages, which tend to become blocked. Production is therefore stopped for cleaning operations of the ventilation passages. In the prior art, the cleaning operations require the disassembly of several parts, which are not easily disassembled.

[0009] Another common defect in molded preforms is the presence of visible marks, usually in the form of lines, due to the presence of ventilation paths. This defect occurs particularly on the preform neck and is caused by ventilation paths at the parting line of the mold parts that mold the outer surface of the preform neck.

[0010] Therefore, there is a perceived need to reduce defects in preforms caused by inadequate evacuation of gas from the molding cavity.

[0011] It is also perceived that there is a need to reduce or eliminate defects in preforms, particularly at the neck, due to the presence of ventilation passages in the mould. SUMMARY OF THE INVENTION

[0013] The object of the present invention is to improve the evacuation of gases from the moulding cavity in order to reduce defects in the moulded preforms.

[0014] Another object of the present invention is to reduce blockage of the ventilation passages, thereby reducing maintenance for cleaning the ventilation passages.

[0015] Another object of the present invention is to reduce the defects of the preform, in particular at the neck, due to the presence of ventilation channels.

[0016] Another object of the invention is to simplify maintenance operations of the molding plant, in particular by reducing the number of parts to be disassembled in order to perform cleaning operations.

[0017] Another object of the present invention is to simplify the structure of the molding equipment.

[0018] The present invention achieves such an object, as well as at least one of the other objects that will become apparent from the present description, by means of an apparatus as described below, for molding one or more bottle preforms by injecting molten plastic, the molding apparatus being provided with at least one molding cavity adapted to receive the molten plastic, and being provided with at least one passage for the passage of air from the at least one molding cavity to the outside of the molding apparatus; the at least one passage being adapted to be connected to a suction device adapted to extract air from the at least one molding cavity;

[0019] wherein the at least one molding device comprises:

[0020] a first component or core adapted to mold an interior surface of the preform;

[0021] a second member or locking ring, the second member or locking ring being disposed about the first member;

[0022] and a third component or neck ring adapted to mold to the outer surface of the neck of the preform;

[0023] wherein the at least one channel is defined in part by the first component and the third component, and wherein the at least one channel is defined in part by the first component and the second component;

[0024] wherein the first component includes at least a first surface, the at least first surface being in contact with at least a second surface of the second component;

[0025] wherein the first surface and / or the second surface is provided with at least one groove, the at least one groove partially defining the at least one channel;

[0026] The first surface and the second surface are in the shape of a truncated cone.

[0027] In particular, the moulding apparatus is configured to be connected to a suction device such that the suction device can extract air from the moulding cavity through the at least one channel.

[0028] The invention also relates to an apparatus for moulding one or more bottle preforms by injecting molten plastic, said apparatus comprising at least one moulding device as described above, and suction means connected to said at least one channel, said at least one channel being suitable for extracting air from said at least one moulding cavity.

[0029] The invention also relates to a method for molding one or more bottle preforms, said method being performed by means of the device described above or by means of the apparatus described above, wherein molten plastic is injected into at least one molding cavity;

[0030] And wherein air is extracted from at least one molding cavity through the at least one channel by a suction device connected to the at least one channel so that air passes from the at least one molding cavity to the outside of the molding device.

[0031] Such a method advantageously allows gases, particularly air and any volatile compounds or debris, to be effectively removed from the moulding cavity.

[0032] In fact, by activating the suction device, an air flow is generated from the molding cavity to the outside of the molding device. More specifically, a low air pressure, ie a vacuum, is generated in the molding cavity.

[0033] This therefore allows the formation of air pockets and the occurrence of mold cavity filling failure to be avoided or minimized during the injection of the molten plastic.

[0034] Advantageously, defects in the molded preform, such as, inter alia, burrs, burns and flow lines, are avoided or minimized.

[0035] Furthermore, the extraction advantageously allows avoiding or minimizing the accumulation of volatile compounds or debris on the mold surfaces defining the ventilation passages (when provided).Thus, the maintenance frequency, in particular for cleaning the ventilation passages, is reduced.

[0036] Furthermore, the method and apparatus of the present invention advantageously allow the clearance of ventilation passages of the component (which molds the outer surface of the preform neck, ie the component called "neck ring") to be reduced, especially the ventilation passages adjacent to the molding surface.

[0037] Thus, on the molded preform neck, linear defects that may occur at the parting line of the neck ring are minimized.

[0038] The method, apparatus and instrument of the present invention also advantageously provides the opportunity to eliminate ventilation paths adjacent to the molding surface of the neck ring.In this specific non-limiting embodiment, the possibility of the above-mentioned linear defects on the neck of the preform is minimized or eliminated.

[0039] The suction device (for example comprising or consisting of a pump or a suction fan) can advantageously be connected to an air distribution system, with which known apparatuses are also provided, wherein such an air distribution system is dedicated to the process of extracting the preforms by introducing air into the molding apparatus. Thus, the apparatus and the device according to the invention allow the use of the same air distribution system for both extracting air from the molding cavity before and / or during the injection of the molten plastic, and for introducing air during the preform extraction step.

[0040] However, specific embodiments may be provided in which the apparatus comprises two separate air distribution systems, one for extraction to create a vacuum in the moulding cavity and one for introduction of air to extract the preform.

[0041] In addition to effectively allowing the extraction described above to be carried out, the molding device advantageously allows simplifying maintenance operations, in particular by reducing the number of parts to be disassembled in order to carry out cleaning operations, and can be manufactured in a particularly simple and affordable manner. In fact, it is not necessary to arrange a part (called ventilation ring or core ring) between the third part (neck mold) and the first part (core) and between the second part (locking ring) and the first part, and preferably, it is not provided.

[0042] The absence of ventilation rings greatly simplifies maintenance operations, in particular cleaning operations, and further simplifies the manufacture of the molding apparatus. The absence of ventilation rings also allows to reduce undesirable visible marks on the molded preforms.

[0043] Furthermore, in the side wall of the locking ring, in particular at the frustoconical portion of the locking ring, advantageously no holes are required and preferably no holes are provided. The presence of such holes would indeed complicate the manufacture of the molding equipment (such holes in fact generally have a large length / diameter ratio) and such holes would be difficult to clean.

[0044] Optionally, the one or more holes are provided only in the end portion of the locking ring remote from the moulding cavity.

[0045] Further features and advantages of the present invention will become more apparent from the detailed description of exemplary but non-exclusive embodiments.

[0046] The dependent claims describe particular embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In the description of the present invention, reference is made to the accompanying drawings, which are provided by way of non-limiting examples and in which

[0049] In the figure:

[0050] Figure 1 An example of an apparatus according to the invention is schematically shown;

[0051] Figure 2 shows a cross section of an example of a device according to the invention;

[0052] Figure 3 Schematically shows Figure 2 The cross section of

[0053] Figure 3A Shows Figure 2 a side view of a portion of a component of a device;

[0054] Figure 3B A perspective view showing an example of components of the device according to the invention;

[0055] Figure 3C shows a cross section of an example of a device according to the invention;

[0056] Figure 4 Shows Figure 2 The enlarged details;

[0057] Figure 5 Shows Figure 4 The enlarged details;

[0058] Figure 6 shows a cross section of another example of a molding apparatus;

[0059] Figure 7 Schematically shows Figure 6 The cross section of

[0060] Figure 8 Shows Figure 6 The enlarged details;

[0061] Fig. 9 Shows Figure 8 The enlarged details;

[0062] Fig.10 Schematically shows Figure 3 a portion of a cross section;

[0063] Fig.11 A cross section showing an example of two parts of a component of a device according to the invention;

[0064] Fig.12 Shows Fig.11 a perspective view of a portion of a component;

[0065] Fig.13 Shows Fig.12 The enlarged details;

[0066] Fig.14 A cross section showing another example of two parts of a component of a device according to the invention;

[0067] Fig.15 Shows Fig.14 a perspective view of a portion of a component;

[0068] Fig.16 Shows Fig.15 The enlarged details.

[0069] Identical elements and components, or elements and components that are substantially functionally equivalent, have the same reference numerals.

[0070] Description of Exemplary Embodiments of the Invention

[0071] With reference to the accompanying drawings, an embodiment of an apparatus 100, a device 1 and a method for molding one or more bottle preforms (not shown) is described. In particular, the preform is manufactured by injecting molten plastic (or in other words, molten polymer) into a molding cavity 5. The preform is, for example, made of polyethylene terephthalate (PET).

[0072] In all embodiments, the apparatus 100 comprises at least one molding device 1 , also referred to as an injection stack assembly.

[0073] The moulding device 1 defines an axis X, preferably a longitudinal axis.

[0074] The molding device 1 is provided with at least one molding cavity 5 adapted to receive molten plastic, and at least one channel 2 for passage of air from the at least one molding cavity 5 to the outside of the molding device 1 .

[0075] In particular, the at least one channel 2 is outside the moulding cavity 5 , in particular completely outside the moulding cavity 5 .

[0076] The apparatus 100 further comprises suction means 102, for example comprising or consisting of a pump or a suction fan, connected to said at least one channel 2, the channel 2 being suitable for extracting air from the at least one moulding cavity 5. In addition to air, the suction means 102 can also extract debris, for example organic particles, which are substantially entrained by the suction air flow.

[0077] The apparatus 100 preferably comprises a plurality of moulding devices 1. In this case, a suction device 102 is preferably connected to the channel 2 of each moulding device 1.

[0078] In particular, the molding device 1 comprises the following components:

[0079] - a part called core 10 which defines the inner surface of the preform, ie having a molding surface 10b ( Figure 3A ), the molding surface 10b molds the inner surface of the preform, preferably the inner surface of the entire preform. The molding surface 10b is the end portion of the core 10, while the remaining part of the core 10 is outside the molding cavity 5. The pipe 11, also called cooling pipe, which is particularly used to cool the core 10 and thus the preform, is preferably arranged inside the core 10. Air can be introduced into the molding device 1 through the pipe 11.

[0080] A part called neck mould 30 or neck ring or neck insert which defines the outer surface of the preform neck, i.e. has a moulding surface which moulds the outer surface of the preform neck, including the threaded portion (when provided). The neck mould 30 comprises two neck half-moulds 31 , 32 .

[0081] - a support member, called a support ring 20 or a locking ring, which is preferably a substantially annular body. The support ring 20 serves in particular to support the core 10 and to ensure its correct alignment. The support ring 20 thus constrains the core 10. The support ring 20 also surrounds the core 10, in particular around the portion of the core 10 outside the molding cavity 5. The end of the support ring 20 preferably abuts against the neck mold 30.

[0082] The molding device 1 also includes a part called a main body mold 61 or cavity, which defines the outer surface of the preform body, for example, the part has a molding surface, which molds at least or only the outer surface of the preform body. The preform body is adjacent to the preform neck and preferably includes at least one substantially cylindrical portion. Therefore, the molding surface of the main body mold 61 preferably includes at least a substantially cylindrical portion.

[0083] The main body mold 61 is a component different from the neck mold 30 .

[0084] The molding device 1 preferably also includes a component called a gate insert 62, which is suitable for molding the outer surface of the bottom of the preform, for example a substantially hemispherical surface. The molten plastic is injected through the gate insert 62. In a variant not shown, the main mold 61 can also optionally mold the outer surface of the bottom part of the preform, essentially playing the role of the gate insert 62 when the gate insert 62 is not present.

[0085] The molding apparatus 1 preferably further comprises a flange 63 , also called cavity flange, which is fastened to the body mold 61 and is arranged around the neck mold 30 and the body mold 61 .

[0086] The moulding cavity 5 is defined by the core 10, the neck mould 30, 30', the body mould 61 and optionally by a gate insert 62 when one is provided.

[0087] Specific reference Figures 2 to 5 , the channel 2 is defined by the core 10, the neck mold 30 and the support ring 20. In particular, the channel 2 is partially defined by the neck mold 30 and the core 10, and partially defined by the support ring 20 and the core 10. In more detail, the channel 2 is at least partially defined by the inner surface of the support ring 20 (in particular the inner side surface) and at least a portion of the inner surface of the neck mold 30 (in particular the inner side surface), which face the outer surface of the core 10. The distance between the outer surface of the core 10 and the inner surface of the neck mold 30, in particular the distance transversely relative to the axis X, can be, for example, 0.1 mm to 5 mm; and / or the distance between the outer surface of the core 10 and the inner surface of the support ring 20, in particular the distance transversely relative to the axis X, can be, for example, 0.1 mm to 10 mm.

[0088] The channel 2 is preferably defined only by the core 10 , the neck mould 30 and the support ring 20 .

[0089] Preferably, there is no component or intermediate (i.e., intervening body) between the neck mold 30 and the core 10; in particular, the inner surface of the neck mold 30 directly faces a portion of the outer surface of the core 10. Furthermore, preferably, there is no intermediate component between the support ring 20 and the core 10; in particular, the inner surface of the support ring 20 directly faces a portion of the outer surface of the core 10.

[0090] In particular Figure 4 and Figure 5 As shown, the molding device 1 is preferably configured so that the core 10 and the neck mold 30 are spaced apart from each other, also parallel to the axis X, so as to allow air to pass from the molding cavity 5 to the channel 2. The inlet of the channel is substantially close to the area where the edge of the mouth of the preform is molded. Preferably, the surface 33 ( Figure 5 ) faces the surface 13 of the core 10 and is spaced apart therefrom to allow the above-mentioned passage from the molding cavity 5 to the channel 2.

[0091] In particular, the surface 33 is a non-molding surface, adjacent to the molding surface 39 of the neck mold 30 , and the surface 33 is substantially perpendicular to the axis X.

[0092] Surface 33 and surface 13 are preferably annular.

[0093] It should be particularly noted that when the molding apparatus 1 is in the closed position, ie the position in which molten plastic is injected, the core 10 and the neck mold 30 are spaced apart from each other to allow access to the channel 2 from the molding cavity 5 as described above.

[0094] The above-mentioned distance between the core 10 and the neck mold 30, for example, the distance between the surface 33 and the surface 13, is preferably 0.005 to 0.07 mm.

[0095] The path followed by the air extracted from the moulding cavity 5 through the channel 2 is partly composed of Figure 3 and Figure 4 The arrows in the figure represent schematically.

[0096] The channel 2 is in communication with the molding cavity 5 on one side, while on the opposite side, in particular the opposite side parallel to the axis X, the channel 2 is in communication with the outside of the molding device 1, in particular with the suction device 102, for example through two or more holes 22', 22" in the end portion of the support ring 20, in particular in the longitudinal end portion remote from the molding cavity 5. Alternatively, the channel 2 can also be in communication with the outside in other ways, for example by providing an annular opening around the axis X in the end portion of the support ring 20, or by providing one or more grooves on the outer surface of the end portion of the core 10 and / or on the inner surface of the support ring 20. In other words, the molding device 1 comprises an extension (stretch) or a passage obtained in the end portion of the molding device 1, preferably of the second part 20, remote from the molding cavity 5. The at least one channel 2 can be in communication with the outside of the molding device 1, in particular with the suction device 102, by means of the extension. In other words, the extension substantially forms a part of the at least one channel 2, i.e. the at least one channel comprises the extension.

[0097] The molding device 1 comprises at least one region 24, in particular an annular region, in which the core 10 and the support ring 20 are in contact with each other so that the support ring 20 can ensure the correct alignment of the core 10. In particular, the core 10 comprises a frustoconical surface 10a ( Figure 3A ), and the support ring 20 includes a frustoconical surface 20a ( Figure 3 ), the two truncated cone surfaces 10a, 20a are in contact with each other. In order to allow air to pass effectively, the truncated cone surface 10a of the core 10 and / or the truncated cone surface 20a of the support ring 20 are provided with at least one groove 10c, 20c ( Figure 3A The groove 10c of the core 10 is shown; Figure 3B and 3CA groove 20c of the locking ring 20 is shown, which defines a portion of the channel 2. For example, one, two or more grooves 10c or recesses formed in the frustoconical surface 10a of the core 10 may be provided, and / or one, two or more grooves 20c or recesses formed in the frustoconical surface 20a of the support ring 20 may be provided. The groove 10c (one or more than one) of the core 10 and / or the groove 20c (one or more than one) of the support ring 20 preferably extend substantially longitudinally. In particular, each groove 10c extends from the molding cavity 5 in a distal direction. Each groove 10c, 20c is preferably a straight line or substantially a straight line. The depth of each groove 10c may be, for example, 0.1 mm to 5 mm, and the same is true for each groove of the support ring 20.

[0098] The above-mentioned frustoconical surfaces 10 a , 20 a serve in particular to allow correct centering of the core 10 .

[0099] Special reference Figure 3A , the core 10 comprises a moulding portion or surface 10b, i.e. the moulding portion or surface 10b is adapted to define the inner surface of the preform. The frustoconical surface 10a is different from the portion 10b, i.e. the frustoconical surface 10a is not a moulding surface. Preferably, a cylindrical portion or surface 10e is arranged between the moulding portion 10b and the frustoconical portion 10a. In particular the cylindrical surface 10e is adapted to face the surface of the neck mould 30. Preferably a portion or surface 10d is provided, which is adapted to face the surface 20d of the support ring 20, adjacent to the frustoconical portion 10a. As described above, the surface 10d and the surface 20d are separated from each other, thereby defining a part of the channel 2. Optionally, the groove 10c also extends partially in the surface 10d. The surface 10d is preferably cylindrical.

[0100] exist Figures 2 to 5 In the illustrated embodiment, air extracted by the suction device 102 flows out of the molding cavity 5 and is introduced into the annular portion of the channel 2 defined by the core 10 and the neck mold 30; the air is introduced into one or more grooves 10c, 20c of the core 10 and / or the support ring 20, particularly at the area 24; the air is introduced into the annular portion of the channel 2 defined by the core 10 and the support ring 20; the air is introduced into an extension or passage formed in the end portion of the molding device 1, for example, in the holes 22', 22" of the support ring 20, whereby the air flows out of the molding device 1.

[0101] In other words, the at least one channel 2 comprises a first extension or initial extension defined by a portion of the inner surface of the third component 30 and by a portion of the outer surface of the first component 10 (these portions face each other); a second extension defined by the at least one groove 10c, 20c, preferably partially defined by the at least one groove 10c, 20c; and a third extension defined by a portion of the inner surface of the second component 20 and a portion of the outer surface of the first component 10 (these portions face each other). More specifically, the second extension is preferably defined by each groove 10c, 20c and the facing portion of the frustoconical surface of the core 10 or the locking ring 20 (depending on whether it is a groove 10c of the core 10 or a groove 20c of the locking ring 20).

[0102] The first extension portion is close to the molding cavity 5 ; and the second extension portion is located between the first extension portion and the third extension portion.

[0103] The first, second and third extensions are arranged sequentially to one another, in particular along the axis X. Thus, the air extracted from the moulding cavity 5 passes sequentially through the first, second and third extensions.

[0104] The above-mentioned extension portion (also referred to as a fourth extension portion) formed in the end portion of the molding apparatus 1 is provided after the third extension portion.

[0105] In particular, the channel 2 is substantially a continuous channel, comprising the first extension, the second extension, the third extension and the fourth extension.

[0106] Merely by way of example, when more than one groove 10c and / or 20c is provided at the region 24, the second extension of the channel preferably comprises a corresponding number of passages.

[0107] The above-mentioned first extension is in particular defined by a non-molded surface of the third component 30 .

[0108] The first extension and the third extension of the at least one channel 2 are preferably annular in shape.

[0109] Specific reference Figures 6 to 9 , shows a molding device 1 ' further comprising an annular body 40, also referred to as a venting ring or core ring. In particular, the annular body 40 is arranged partly between the neck mold 30' and the core 10', and partly between the support ring 20' and the core 10'. The annular body 40 is preferably provided with a frustoconical surface in contact with the frustoconical surface of the support ring 20'.

[0110] The channel 2' is defined by the core 10', the annular body 40 and the support ring 20'. In particular, the channel 2' is partially defined by the annular body 40 and the core 10', and partially defined by the support ring 20' and the core 10'. In more detail, the channel 2' is at least partially defined by the inner surface of the support ring 20' and at least partially by the inner surface of the annular body 40, which inner surfaces face the outer surface of the core 10'. The distance between the outer surface of the core 10 and the inner surface of the annular body 40, in particular the distance transversely relative to the axis X, can be, for example, 0.1 mm to 5 mm; and / or the distance between the outer surface of the core 10' and the inner surface of the support ring 20', in particular the distance transversely to the axis X, can be, for example, 0.1 mm to 10 mm.

[0111] A portion of the channel 2' is preferably formed by one or more holes 41 ( Figure 6 , Figure 7 and Figure 8 ) is defined, these holes are preferably transverse to the axis X, and the annular body 40 is provided with these holes.

[0112] The channel 2 ′ is preferably defined only by the core 10 ′, the annular body 40 and the support ring 20 ′.

[0113] In particular Figure 8 and Fig. 9 As shown, the molding device 1' is preferably configured so that the core 10' and the annular body 40 are spaced apart from each other, in particular transversely to the axis X, so as to allow air to enter the channel 2' from the molding cavity 5. The inlet of the channel is substantially located in the area where the edge of the preform mouth is molded.

[0114] The path followed by the air extracted from the moulding cavity 5 through the channel 2' is partly composed of Figure 7 and Figure 8 The arrows in the figure represent schematically.

[0115] The channel 2' is connected to the molding cavity 5 on one side, and on the opposite side, in particular the opposite side parallel to the axis X, the channel 2' is connected to the outside of the molding device 1', for example through two or more holes 22', 22" in the end part of the support ring 20' (in particular the longitudinal end part away from the molding cavity 5). Alternatively, the channel 2' can also be connected to the outside in other ways, for example by providing an annular opening around the axis X in the end part of the support ring 20', or by providing one or more grooves on the outer surface of the end part of the core 10' and / or on the inner surface of the support ring 20'.

[0116] exist Figures 6 to 9In the example shown, the air extracted by the suction device 102 flows out of the molding cavity 5 and is introduced into the annular portion of the channel 2' defined by the core 10' and the annular body 40; the air is introduced into one or more holes 41 of the annular body 40; the air is introduced into the annular portion of the channel 2' defined by the core 10' and the support ring 20'; the air is introduced into the holes 22', 22" of the support ring 20', and the air thereby flows out of the molding device 1'.

[0117] Molding equipment 1( Figure 2 , Figure 3 , Figure 4 ) relative to the molding device 1 '( Figure 6 , Figure 7 , Figure 8 ) is more advantageous.

[0118] Indeed, the absence of the annular body 40 greatly simplifies maintenance operations (in particular cleaning) of the molding device 1 relative to the molding device 1 ′. Indeed, the number of parts that need to be disassembled is smaller and there are fewer areas where debris may accumulate.

[0119] Due to the annular body 40, another interface is created with respect to the molding device 1. Said interface creates undesirable visible marks on the edge of the preform mouth. In addition, due to the annular body 40, there are also areas where debris penetrates and must therefore be cleaned.

[0120] In more detail, the absence of the annular body 40 and the consequent formation of a dividing surface not between the annular body 40 and the core 10 but between the core 10 and the neck ring 30 results in such a dividing surface being easily accessible and therefore directly cleanable without the need to disassemble any part of the molding device 1. In order to make such a surface accessible, it is sufficient to position the mold in the extraction position, which is already provided in the standard operating cycle.

[0121] Special References Figures 10 to 14 In all embodiments, the neck mould 30, 30' comprises two parts or two half-moulds 31, 32, as already mentioned. The half-moulds 31, 32 can be mounted and dismounted from one another and are substantially similar to one another.

[0122] Each mold half 31, 32 comprises a respective molding surface 39. A respective surface 38', 38" extends from each side of the molding surface 39. The surfaces 38', 38" are adjacent to the molding surface 39 and are non-molding, ie they are not intended to come into contact with the molten plastic to mold the preform.

[0123] Although only the surfaces 38 ′, 38 ″ of the mold half 31 are shown, the mold half 32 is also provided with similar surfaces.

[0124] Each surface 38 ′, 38 ″ of the half-mold 31 faces a corresponding surface 38 ′, 38 ″ of the half-mold 32 .

[0125] The grooves 37', 37" are preferably lower relative to the surfaces 38', 38", and are preferably arranged laterally to each surface 38', 38". A portion of the grooves 37', 37" is preferably adjacent to the corresponding surface 38', 38". When the two half-molds 31, 32 are assembled, the grooves 37', 37" define channels 201, 202 for air and possible debris to flow out of the molding cavity 5. In particular, the groove 37' of the half-mold 31 and the corresponding groove 37' of the half-mold 32 define the channel 201 (the two grooves 37' face each other); and similarly, the groove 37" of the half-mold 31 and the corresponding groove 37" of the half-mold 32 define the channel 202 (the two grooves 37" face each other). The channels 201, 202 are connected to the outside of the molding device 1, 1'.

[0126] In the first variant ( Figures 11 to 13 ), at least one corresponding ridge 36', 36" extends from each surface 38', 38". Therefore, when the two half-molds 31, 32 are assembled, each surface 38', 38" of the half-mold 31 is spaced apart from the corresponding surface 38', 38" of the half-mold 32, for example, the distance of the spacing is 0.005mm to 0.07mm, preferably 0.005mm to 0.01mm.

[0127] In particular, surface 38' of mold half 31 is spaced from surface 38' of mold half 32; and surface 38" of mold half 31 is spaced from surface 38" of mold half 32. Thus, two passages of the neck mold 30 are defined through which air and possible debris can pass.

[0128] Advantageously, since air extraction from the moulding cavity 5 is provided, a very small distance can be chosen between the surfaces 38' facing each other and the surfaces 38" facing each other, for example from 0.005 to 0.01 mm. As a result, the indentations produced on the preform due to the presence of the surfaces 38' spaced apart from each other and the presence of the surfaces 38" spaced apart from each other are minimized or substantially absent. Furthermore, debris that may have accumulated on the surfaces 38', 38" can advantageously be removed by suction, and its accumulation can be avoided or slowed down. The suction device 102 can actually be connected to the channels 201, 202 in order to extract air from the moulding cavity 5 to the outside.

[0129] In the second variant ( Figures 14 to 16), the neck molds 30, 30' are constructed so that when the two half molds 31, 32 are assembled to each other, each surface 38', 38" of the half mold 31 is adjacent to (ie in contact with) the corresponding surface 38', 38" of the half mold 32.

[0130] In particular, with regard to the previous variants, no ridges are provided to act as spacers.

[0131] Thus, the possibility of linear defects on the preform neck due to separation of the surfaces 38', 38" is substantially eliminated.

[0132] The configuration in which each surface 38 ′, 38 ″ of the half-mold 31 can abut against a corresponding surface 38 ′, 38 ″ of the half-mold 32 is achieved by sucking air from the molding cavity 5 by means of the suction device 102 .

[0133] In all embodiments, the suction device 102 may be connected to the channels 2, 2' and / or to one or more channels 201, 202 defined by the neck mold 30. The one or more channels 201, 202 of the neck mold 30, 30' communicate with the molding cavity 5. Such channels 201, 202 may be defined, for example, by each groove 37', 37" of the half-mold 31 facing a corresponding groove 37', 37" of the half-mold 32, as described above.

[0134] Figure 1 The non-limiting example of the apparatus 100 shown provides a suction device 102 which is connected to the moulding apparatus 1 , 1 ′ (or to a plurality of moulding apparatuses 1 , 1 ′) by means of a conduit or conduit system 103 .

[0135] In particular, the suction device 102 is preferably connected to a plate, in particular a core holder plate (not shown), to which end portions of the core 10, 10' are constrained.

[0136] In all embodiments, the molding device 1 , 1 ′ preferably comprises a sealing ring 23 , in particular an O-ring 23 , such as an elastic sealing ring, to improve the sealing during the extraction process.

[0137] In particular, the sealing ring 23 is arranged between the support ring 20, 20' and the plate, in particular the core holder plate. Thus, a suction air flow can flow out of the molding device 1, 1', in particular by passing through an extension formed in the end portion, for example through the hole 22', 22", and is introduced into the core holder plate, from which the air flow can leave.

[0138] For example, the duct system may include a first extension 103a connected to the molding device 1, 1'. When a plurality of molding devices 1, 1' are provided, a plurality of first extensions 103a are preferably provided, each of which is connected to a corresponding molding device 1, 1'. The first extension 103a is connected to the second extension 103b and the third extension 103c. The second extension 103b is connected to the suction device 102, such as a pump or a suction fan. Preferably, the valve 104 is provided between the first extension 103a and the suction device 102. In particular, the valve 104 is preferably arranged along the second extension 103b.

[0139] The third extension 103c is connected to a device 106, such as a compressor, suitable for introducing air into the molding device 1, 1', for example through the pipe 11. Preferably, the valve 105 is arranged between the first extension 103a and the device 106. In particular, the valve 105 is preferably arranged along the third extension 103c. Therefore, depending on the opening state of the valves 104, 105, the suction device 102 can extract air from the molding device 1, 1', and the device 106 can alternately introduce air into the molding device 1, 1'.

[0140] Obviously, other configurations may also be provided, for example a single three-way valve may be provided, or separate conduits may be provided for the suction device 102 and the device 106. The suction device 102 is preferably distinct from the device 106. In any case, the device 106 is optional.

[0141] The invention also relates to a method for moulding one or more bottle preforms, which method can be carried out, for example, by means of the apparatus 100 .

[0142] The molten plastic is injected into the molding cavity 5 to mold the preform.

[0143] Advantageously, the method provides that air is extracted from the molding cavity 5 through the at least one channel 2, 2', 201, 202 so that air passes from the molding cavity 5 to the outside of the molding device 1, 1'. The air is extracted by the suction device 102 and is particularly directed to the outside of the molding device 1, 1'. The duct of the molding device 1, 1' that connects the molding cavity 5 with the suction device 102 can be the duct 2, 2' and / or can be one or both of the ducts 201, 202.

[0144] Preferably, air is extracted from the molding cavity 5 before and / or during the injection of molten plastic into the molding cavity 5. In particular, air may be extracted from the molding cavity 5 during all or part of the time when the molten plastic is injected into the molding cavity 5.

[0145] As mentioned above, extracting air from the moulding cavity 5 allows, among other advantages mentioned above, in particular to avoid the formation of air pockets in the moulding cavity and to allow the molten plastic to fully fill the moulding cavity.

[0146] After the injection of the molten plastic, air is preferably introduced into the molding device 1 , 1 ′ by means 106 .

Claims

1. An apparatus (100) for molding one or more bottle preforms by injecting molten plastic, comprising: At least one molding device (1) provided with: at least one molding cavity (5) adapted to receive said molten plastic, and at least one passage (2) for passing air from the at least one molding cavity (5) to the outside of the at least one molding device (1); wherein the at least one molding device (1) comprises: a first component or core adapted to mold the interior surface of the preform; a second member or locking ring disposed about said first member; and a third component or neck ring adapted to mold the outer surface of the neck of said preform; wherein the at least one channel (2) is partially defined by the first component and the third component, and the at least one channel (2) is partially defined by the first component and the second component; wherein the first component comprises at least one first surface (10a), and the at least one first surface (10a) contacts with at least one second surface (20a) of the second component; wherein the first surface (10a) and / or the second surface (20a) is provided with at least one groove (10c, 20c), and the at least one groove (10c, 20c) partially defines the at least one channel (2); wherein the first surface (10a) and the second surface (20a) are truncated cone-shaped; It is characterized in that The at least one channel (2) is suitable for being connected to a suction device (102), the suction device (102) being suitable for extracting air from the at least one molding cavity (5); The apparatus (100) comprises the suction device (102) connected to the at least one channel (2), the suction device (102) being suitable for extracting air from the at least one molding cavity (5); The suction device (102) is connected to the at least one molding device (1) by means of a conduit system (103); The conduit system (103) comprises a first extension (103a) connected to a molding device (1) of the at least one molding device (1); The first extension portion (103a) is connected to the second extension portion (103b) and the third extension portion (103c); The second extension (103b) is connected to the suction device (102); The third extension (103c) is connected to means (106) suitable for introducing air into the at least one molding device (1); And a first valve (104) is arranged between the first extension (103a) and the suction device (102), and a second valve (105) is arranged between the first extension (103a) and the device (106) suitable for introducing air.

2. The apparatus (100) according to claim 1, wherein: The at least one channel (2) comprises: a first extension portion defined by a portion of an inner surface of the third member and a portion of an outer surface of the first member facing each other; a second extension defined by the at least one groove (10c, 20c); and a third extension portion defined by a portion of the inner surface of the second member and a portion of the outer surface of the first member facing each other.

3. The apparatus (100) according to claim 2, wherein: The first extension of the at least one channel (2) is close to the molding cavity (5); and the second extension of the at least one channel (2) is located between the first extension and the third extension of the at least one channel (2).

4. The apparatus (100) according to claim 2, wherein: The first extension portion, the second extension portion and the third extension portion of the at least one channel (2) are arranged sequentially with each other so that the air extracted from the molding cavity (5) passes through the first extension portion, the second extension portion and the third extension portion of the at least one channel (2) sequentially.

5. The apparatus (100) according to claim 3, wherein: The first extension portion, the second extension portion and the third extension portion of the at least one channel (2) are arranged sequentially with each other so that the air extracted from the molding cavity (5) passes through the first extension portion, the second extension portion and the third extension portion of the at least one channel (2) sequentially.

6. The apparatus (100) according to any one of claims 1 to 5 comprises an extension portion formed in an end portion of the molding device (1) away from the molding cavity (5), through which the at least one channel (2) can be connected to the outside of the molding device (1).

7. The apparatus (100) according to claim 6, comprising said extension formed in an end portion of said second part remote from said moulding cavity (5).

8. The apparatus (100) according to claim 6, wherein: By means of the extension formed in the end portion, the at least one channel (2) can be in communication with the suction device (102).

9. The apparatus (100) according to any one of claims 1-5, 7-8, wherein: Two or more holes (22', 22") are provided in the end portion of the second component; or an annular opening is provided in the end portion of the second component; or one or more grooves are provided on the outer surface of the end portion of the first component and / or on the inner surface of the second component.

10. The apparatus (100) according to claim 9, wherein: Through the two or more holes (22', 22") or the annular opening or the one or more grooves, the at least one channel (2) can communicate with the outside of the molding device (1).

11. The apparatus (100) according to claim 10, wherein: Through the two or more holes (22', 22") or the annular opening or the one or more grooves, the at least one channel (2) can be in communication with the suction device (102).

12. The apparatus (100) according to any one of claims 1-5, 7-8, 10-11, wherein: The at least one channel (2) is defined by a non-molded surface of the third component.

13. The apparatus (100) according to claim 12, wherein: A first extension of the at least one channel (2) is defined by a non-molded surface of the third component.

14. The apparatus (100) according to any one of claims 1-5, 7-8, 10-11, 13, wherein: The third component comprises surfaces (38', 38") facing each other and adjacent to the molding surface (39) of the third component, wherein the surfaces (38', 38") abut against each other, or wherein the distance between the surfaces and each other is 0.005mm to 0.07mm, or 0.005mm to 0.01mm.

15. The apparatus (100) according to any one of claims 1-5, 7-8, 10-11, 13, wherein: At least in some areas, the at least one channel (2) is annular in shape.

16. The apparatus (100) according to any one of claims 2 to 5, wherein: The first extension and the third extension of the at least one channel (2) are annular in shape.

17. The apparatus (100) according to any one of claims 1-5, 7-8, 10-11, 13, comprises a component (61) or a main body mold, wherein the component (61) or the main body mold is suitable for molding the outer surface of the preform body; the component (61) is different from the third component.

18. The apparatus (100) according to any one of claims 1-5, 7-8, 10-11, 13, wherein: There are no intermediate components between the third component and the first component; and / or wherein there are no intermediate components between the second component and the first component.

19. The apparatus (100) according to any one of claims 1-5, 7-8, 10-11, 13, comprising a plurality of said molding devices (1), and wherein: A plurality of said first extensions (103a) of said conduit system (103) are provided, each of said first extensions of said conduit system (103) being connected to a respective moulding apparatus (1) of said plurality of moulding apparatuses (1).

20. A method for molding one or more bottle preforms, the method being performed by means of an apparatus (100) according to any one of claims 1 to 19, wherein molten plastic is injected into the at least one molding cavity (5); And among them, Air is extracted from the at least one molding cavity (5) through the at least one channel (2) by a suction device (102) connected to the at least one channel (2, 2', 201, 202) so that the air passes from the at least one molding cavity (5) to the outside of the at least one molding device (1).

21. The method according to claim 20, wherein: Air is extracted from the at least one moulding cavity (5) before and / or during injection of molten plastic into the at least one moulding cavity (5).

22. The method according to claim 20 or 21, wherein: Air is extracted from the at least one molding cavity (5) during all or part of the time that the molten plastic is injected into the at least one molding cavity (5).

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