AU721062B2 - Blow-moulding handled containers in PET or like plastics and related preforms, methods and apparatus - Google Patents

Description

WO 96/30189 PCT/NZ96/00022 -1- "BLOW-MOULDING HANDLED CONTAINERS IN PET OR LIKE PLASTICS AND RELATED PREFORMS, METHODS AND APPARATUS" TECHNICAL FIELD The present invention relates to improvements in and or relating to blow-moulding handled containers in PET or like plastics and related preforms, methods and apparatus.

BACKGROUND ART While handles have been capable of being integrally provided on extrusion blowmoulded products made from a variety of plastics, it has not until very recently been possible to provide (useful for decanting from the bottle or container) integral handles utilising ISB Technology where the material is of biaxially oriented PET plastics or a plastic having similar moulding characteristics.

PET for containers has certain advantages in that it can provide very thin walled bodies to the containers provided there has been crystalline orientation of a required type during the blow-moulding.

Examples of extrusion blow moulded products that have integral handles abound, see, for example, New Zealand Registered Design Nos, 8122, 9923, 12497, 17569, 18238, 18795, 20395, 20597, 21127, 21317, 21921, 22345, 22802, 22807, 22809, 22950, 25603, and 24739.

One approach to the provision of a handle on a biaxially oriented PET bottle has been that of Labplas NZ Ltd which uses a castellate or bayonet type engagement of a moulded handle structure with the already stretch blow-moulded bottle. See for example, New Zealand Registered Design No. 24233.

Another approach with biaxially oriented PET has been the in-mould location of a premoulded handle form and the subsequent mechanical capturing and/or melding therewith of the container being blown from a standard preform. In this respect see New Zealand Registered Design No. 23888.

UK Patent Application GB 2041286A of Yoshino Kogyoshi Co disclosed a synthetic resin (eg. a saturated polyester resin) bottle being created by the steps of injection moulding a parison with a handle integrally moulded to extend -2from lower regions of the parison neck, and (ii) then after heating the parison and the blowmnould biaxially orienting the container during the blowing. The handle form required must be protected during the blow moulding process by complex mould parts and- the only embodiment envisaged where the handle connects top and bottom to the completed bottle is where the parison itself is moulded with the handle already so connected.

PCTIUS8 1/00056 [W082102369] of M. Thompson discloses a variant of the process of GB 204 1286A where the handle in the completed bottle is connected top and bottom, -yet in the parison or perform, was not ie. injection moulded to be integrally connected at the top only. It also discloses forms (eg. Figure 3) where the handle form is protected during blow moulding between mould parts that require axial separation (with respect to the bottle axis), and forms (Figures 5 to 9) where during blow moulding causes the expanding preform to conform to the handle extremity in the same manner as it does to the mould so as to key the barrel of the bottle to the handle extremity.

Figure 16D of W082/02369 shows a-variant of the Figure 5 to 9 form where mould V pieces as shown in Figures 17A to 17C coact to axially (with respect to the preform/bottle axis) force; The handle of the preform into a cavity defined by mould halves for blow moulding the barrel of the bottle, the mould halves being separable laterally of the preform/bottle axis.

EPA 0061511 Al of Ethyl Corporation discloses the injection moulding of a handled preform, itg optional heat conditioning prior to blow moulding, and its blow moulding while the preformed handle remains protected. It does not show means of capturing the extremity of the preformed handle by the barrel of the blown bottle.

*.:Japanese Patent (1994)6/99986 of Toppan Insatsu Co (published 12 April 1994) discloses the blow moulding of a preform to capture a separately injection moulded handle as well as the blow moulding of a handled preform having at its extremity a handle fixing sheet during the blow moulding step which presents a heat sensitive adhesive layer to the barrel of the bottle being blown so as to trap the handle extremity between the fixing sheet and the barrel.

DIS CLOSURE OF INVENTION ~i~\THE NEXT PAGE IS PAGE 7 EDITORIAL NOTE No. 51272/96 This specification does not contain pages numbered 3 to 6.

7 The present invention provides a method of manufacturing a bottle or container (hereinafter "bottle") of PET which comprises the steps of melting the PET, forming from the molten PET, in a first mould assembly, a preform capable of being stretch blow moulded to the form of the bottle, said preform having a neck region which, once the bottle is formed, is to be engageable by a screw closure to close the mouth or opening thereof and having adjacent but below the threaded neck region, a handle or a precursor for a handle, said handle or precursor for a handle having a distal extremity region, and without allowing the preform to cool (at least to any substantial degree) to a temperature or temperatures below the stretch blow moulding temperature for at least the barrel region thereof to be stretch inflated, in a second mould assembly, stretch blowing the barrel region of the preform to define said bottle, 20 wherein said preform after creation in said first mould assembly is manoeuvred by said neck and/or said handle by part of said first mould assembly into a two part blow mould for said. barrel region and is indexed relative to the centre line thereof by reference to the handle, said two part blow mould (plus its blow nozzle) and said part of first mould assembly form at least part of said second mould assembly, and (ii) in the stretch blow moulding step, means for deflecting the tang or extremity of the handle inwardly towards the remainder of the preform for a sufficient period and in such a way as to enable a better wrap around of the distal regions of the tang or said extremity by the body of the bottle or container being blown from said barrel region, where by presenting the distal region of the handle more inwardly it encounters sooner the plastics material being blown which is both thicker at that position S and hotter.

H:\paulad\Keep\speci\51272-96 CARTER HOLT HARVEY LTD-AMEND.doc 27/04/00 8 Preferably the part lines of those parts of the first mould assembly and those parts of the second mould assembly for said barrel region are substantially coincident.

Preferably said substantially coincident part lines are in a plane or planes that include said handle.

Preferably said means for deflecting the tang or extremity inwardly is means reproducibly moveable to achieve said deflection for a sufficient period of time yet to move so as not to substantially (if at all) interfere with the said wrap around.

Preferably said means is a pivotal member actuated by reciprocating member such a pneumatic, hydraulic or solenoidal member.

Preferably said pivotal member is pivoted from a pivot axis which is substantially perpendicular to the general longitudinal axis of the preform and is (with .i respect to radial projections from the preform) not closer 20 to the neck region of the preform than said distal end of the tang region of said handle.

BRIEF DESCRIPTION OF DRAWINGS In a less preferred form said preform is a 25 previously moulded parison ie. may be used after cooling to ambient temperatures. This however creates some difficult in THE NEXT PAGE IS PAGE 11 H: \pau1d\Keep\speCi\51272-96 CARTER HOLT HARVEY LTO-AMEND.doc 27/04/00 EDITORIAL NOTE No. 51272/96 This specification does not contain pages numbered 9 to WO 96/30189 PCT/NZ96/00022 -11reheating the preform uniformly for stretch blow-moulding because of the integral handle.

A preferred form of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 is a side elevation view of a preferred bottle in accordance with the present invention showing the neck with its screw-fit feature to enable engagement with a closure to seal the opening or mouth thereof and having a shoulder positioned there below from which an integral handle (which was present in the preform) extends and which has a distal end region preferably mechanically captured by the blow-moulded body region, Figure 2 is a view "AA" of the bottle of Figure 1, Figure 3 is a plan view "BB" with respect to the bottle of Figure 1, Figure 4 is a similar side elevation view to that of Figure 1 but of the preform thereof, the neck, shoulder and body precursors of the bottle of Figure 1 being shown in section, the preform showing extending from the shoulder region the preferred form of preform handle structure, and Figures 5A through 5C show in sequence Figure 5A the carrying of the preform after it has been moulded in the injection stations of the injection stretch blow moulding machine by a handling structure which engages to or carries at least in part by the handle structure for subsequent indexing purposes, Figure 5B where the arrangement of Figure 5A has been indexed into a two part blow-mould, the handle being preferably used as a reference to the centre line of the preferred two part mould, Figure 5C showing how, after opening of the mould, the structure of Figure can carry the completed bottle for release at a product collection zone, Figure 6 is a perspective view of a more preferred form of preform clearly showing a strengthened form of handle over that depicted in, for example, Figure 4, the integral handle region of the preform being essentially of two parts, ie. a tang region that extends substantially parallel to the longitudinal preferably circular section of the preform and a shoulder-like region from at or adjacent the neck regions of the preform to the non-distal end region of the tang region, preferably that shoulder-like region being sufficiently WO 96/30189 PCTINZ9600022 -12strengthened by appropriate cross-sectional configuration, ie. webbing, ribbing etc. so as to render it reasonably rigid, Figure 7 is a perspective view of tooling in accordance with the present invention showing by means of the cross hatching those surfaces of various mould parts that need not break (if at all) at that particular part line but showing in relation to the closure engaging region of the mould cavity one of preferably two mould parts that not only define the closure engaging thread but are capable of defining at least in part of the upper or outer surface of said handle and being used in concert to remove a moulded preform from the cavities while at the same time indexing the handle (preferably with its axis) for location subsequently with respect to a blow mould, Figure 8A is the same as Figure 7 showing the apparatus as it would be as the apparatus is about to be charged with the plastics material to form the preform, Figures 7 8A not showing cooling conduiting within parts of the mould that are useful to ensure a preferential cooling of the handle and neck regions of the preform (rather than the blow mouldable regions), Figure 8B shows a preform injection moulded by such cavities, Figure 8C shows the next stage, ie. the removal of the mould part from internally of the preform, Figure 8D is the next stage with sliding out of the preform from its mould cavities while still being retained by the two part mould piece which has defined in the preferred form not only the threaded region but also the outer or upper surface of the shoulder-like region from at or adjacent the neck to the tang region of the handle, and which separation will allow the carousel or other like movement of the preform with respect to the cross hatched mould pieces to the blow mould, Figure 9A follows on from 8D but showing a blowing nozzle or mandrel capable of engaging the supporting two part mould carrying the preform and/or the preform itself when within the blow mould cavity and showing one part of the preferred two part blow mould which will preferably have a part axis indexed to the handle and in common with the preform carrying mould parts and which preferably includes reproducible moveable means which is actuable (for example by pneumatic ram not shown) to bias the handle towards the body proper of the preform, WO 96/30189 PCT/NZ96/00022 -13- Figure 9B shows the apparatus in its assembled form ready for blow moulding with the pivoted member just making contact with the tang region of the handle, Figure 9C is a similar view to that of Figure 9B but showing the inward deflection of the tang region of the handle such that the distal end regions thereof encounter the blown preform plastics material while it is both thicker and hotter to achieve a better wrap around of the distal end region and thus its capture, Figure 9D shows the preform having been blow moulded to achieve such a capture even as the pivoted means moves clear of the capturing plastics material for the distal end region, there being some natural bias on the handle to move outwardly to retain its engagement by the capturing blow moulded material, Figure 9E shows yet a further stage with the blow mould being separated at the part line which is preferably coincident with the part line of the two part mould pieces engaging the closure engageable regions of the neck and/or head, Figure 9F shows the uplifting of the apparatus away from the mould cavity, Figure 9G shows the separation of the still retained container from the blow moulding head, and Figure 10 shows the thus blow moulded container after the part line separation of the two parts of the apparatus that previously both formed the screw thread and part of the shoulder-like of the handle piece of the preform and of course supported it and indexed it during the subsequent stages.

In the preferred form of the present invention the plastics material is PET and is formed into a preform as shown in Figure 4. This preform 1 has a neck region 2, a shoulder region 3 and a body region 9. The handle 4, preferably in its final form, extends from the shoulder 3 and defines a distal region 5 which may be captured by the blown body as shown in Figure 1.

Since the preform of the kind depicted in Figure 4, if cooled to become a parison, presents difficulties for homogeneous heating to a stretch blow moulding temperature [if there is to be reliance on radiant heat or conduction] owing to the presence of the integral handle in the preferred form of the present invention the preform is not cooled to become a parison but is a preform that is only momentarily in existence and is preferably kept at or above a temperature at which it can be stretch blow moulded after it has been formed WO 96/30189 PCT/NZ96/00022 -14from the molten PET. The method of forming can be conventional but preferably as indicated by reference to Figures 5A through 5C the apparatus 6 which carres the preform, by indexing to the handle structure 8 can ensure appropriate location of the handle 8 in the blow mould 7.

Preferably each of the stages of 5A through 5C take place on part of a carousel of a injection stretch blow-moulding machine of substantially a conventional form but which has been modified to accommodate a preform having an integral handle or to be moulded with said integral handle and to have the handle indexed into the blow mould and released therefrom.

A preferred form of the preform as shown in Figure 6. It includes a blowmouldable region 9 which is preferably substantially of circular section but may not be a true annulus in cross-section since some weighting of the material to accommodate for standard moulding practices and the shape of the container may be required, thus resulting in slight variations in wall thickness to achieve the best moulding of the product by a standard blow-moulding technique and yet resulting in a product with the requisite strength. Similarly in relation to the closed bottom end.

The preform as shown in Figure 6 includes a tang region 10 of its handle which extends substantially parallel (With respect to its longitudinal axis) to the corresponding general longitudinal axis of the body member 9. The distal end 11 of the tang region is preferably such that the preform is capable of being uplifted in a direction parallel to the said general longitudinal axes away from the distal end. This is important in order to simplify tooling. Nevertheless, in some forms of the present invention, forms of the distal end 11I can be envisaged that through the rounding, bulbing, or the like may nevertheless be extractable in a similar direction from tooling.

2 5 The general neck region 30 of the preform [preferably below the single or multi start threaded region 14 and the ratchet like means 15 (for tamper evident closures and/or for child proof closures] defines a shoulder-like region 12 that extends to a region 13 where the tang 10 proper commences. The shoulder-like region 12 is preferably provided with a cross-section by means of webs or the like such that a two part mould capable of separation from the longitudinal axis of the shoulder-like 12 can achieve the requisite moulding. Preferably the tang region 10 and its distal end is such that a simple cavity is PCTINZ96/00022 WO 96/30189 all that is required provided the tang 10 can be uplifted therefrom upon being pulled directly or indirectly by the shoulder-like region 12.

A preferred tool arrangement is shown in Figure 7 where the outer member 16 is shown with cross hatching to show what is not necessarily a part line and preferably is not, although could be for the purpose of simplifying manufacture. Likewise the inner member 17 which as a plug locates with respect to the members 16 upwardly from below and opening to allow the movement of plastics is provided at 18 from below via an injection nozzle.

Also shown in Figure 7 cross hatched so as to indicate a surface that has been broken and need not be a part line is the member 19 which has the function of defining the inner surface of the preform. The member 19 co-acts with a mould part 20 which does mate at a part line which is in the same plane as the cross hatched surfaces of each of the members 16, 17 and 19. This mould part defines the threaded region of the preform as well as the upper surface of the shoulder-like region to the tang region. Indeed the region 21 defines the indented regions 22 of the preform shown in Figure 6.

Not illustrated in Figure 7 for convenience are the means whereby fluid passage is achieved through the metal mass of mould part 16 to achieve selective cooling of the tang and/or shoulder-like regions of the preform. Likewise in respect of the members 17, and 19 which may include some provision for heat exchange by use of a non-mingling heat exchange liquid or conductive cooling to such a liquid.

Figure 8A through 9 shows a series of steps from the time of mould assembly on a machine through to the time of preform extraction for movement to a blow moulding zone or station.

Figure 8A shows the arrangement where it is then possible to inject plastics material into the mould cavity.

Figure 8B shows the plastics material as it is after having filled the mould cavity.

Figure 8C shows the arrangement upon the uplifting of the mould part 19 from within the preform body 9 and clear of the head thereof.

Figure 8D shows how in a machine such as SBIII series machines sourced from Aoki Technical Laboratories Inc, of Nagano-ken, Japan how it is possible for mated mould parts to uplift the preform after preliminary cooling such that the neck and handle WO 96/30189 PCT/NZ96/00022 -16regions retain their configuration for movement into a blow-mould while there is still sufficient heat retention in the body region 9, such uplifting being possible without any opening of the mould parts from which it has been withdrawn.

Figure 9 shows how a machine such as an Aoki SBIII series machine can use the members 20 that have moved the preform extracted from the moulding process of Figures 8A through 8D for positioning within a two part blow mould one half of which is shown as 24 in Figure 9A.

There then follows the procedure as depicted in Figures 9A through 9G whereby there is first a presenting of the clamped preform to the open blow-mould, a positioning of the members 20, the blow-mould head 25 and the preform 23 as appropriate to the blow-mould which is then closed, and thereafter the ensuing blowing and extraction procedures, such extraction again being achieved utilising the association of the two part mould 20 with the closure engagement region and the shoulder-like of the handle of the preform.

A blow-moulded container as shown in Figures 10 results with a wrap around at 26 of the distal end region 11 of the preform 23.

A characteristic of blow moulding is that a handle of a preform as shown if left unconstrained against radial outward movement would be deformed outwardly in the blow-mould under the gas pressure within the blown body 9. There is a preference to restrain the handle so that the appropriate association with the blown body can best take place. It has been found possible by a timed urging of the tang region inwardly towards the body 9 (as shown from the conditions shown in Figure 9B to the condition shown in Figure 9C) to achieve a better wrap around provided the means 27 is moved clear to allow such wrap around at the strategic time and to allow opening of the blow mould cavity halves.

The small amount of deflection between the condition of the distal end of the tang shown in Figure 9B through to that shown in Figure 9C is such that a thicker body of the region 9 of the preform while hotter than would otherwise be the case contacts the distal end 11 thus giving rise to a better association and wrap around as the member 27 times its withdrawal to allow the continuation of such a wrap around.

The member 27 is preferably driven about its pivot axis 28 by appropriate means WO 96/30189 PCTINZ6/00022 -17such as a pneumatic ram that would connect at 29 and its timing of movement between the conditions shown throughout Figures 9A to 9G would be such as to maximise the wrap around at 26.

The air cylinder which actuates the pivoted member (in and out) preferably is activated by the same signal as the stretcher rod cylinder (up and down). The timing of the stretcher rod action in relation to the blow valve being activated is through a timed delay ie; blow initiated (low pressure), delay before stretcher rod down initiated, high pressure blow, high pressure blow times out, stretcher rod up, blow mould opens.

Preferably the pivoted member is held 'in' through the total blowing cycle although it could be timed to retract once the preform is fully inflated (preferably within 0.5 sec of initial blow signal). It is highly preferred that the pivoted member is retracted before the blow mould is opened; otherwise the product would be damaged as the support area would be entrapped in the blown contours of the bottle.

Obviously reciprocal means to inwardly urge the tang are possible as to of course are forms that naturally configure the preform to be disposed more inwardly but without sufficient strength to prevent its withdrawal from a simple mould as shown in Figure 7.

Such other constructions are within the ambit of the present invention but the lighter weight forms, but with the urging as depicted, are the most preferred.

Persons skilled in the art will appreciate how the present invention provides a clear alternative to existing methods of providing handles for containers or bottles where the integral handles are not capable of being provided by existing technologies available for plastics such as bi-axially oriented PET.

Claims (6)

1. A method of manufacturing .a bottle or container (hereinafter "bottle") of PET which comprises the steps of melting the PET, forming from the molten PET, in a first mould assembly, a preform capable of being stretch blow moulded to the form of the bottle, said preform having a neck region which, once the bottle is formed, is to be engageable by a screw closure to close the mouth or opening thereof and having adjacent but below the threaded neck region, a handle or a precursor for a handle, said handle or precursor for a handle having a distal extremity region, and without allowing the preform to cool (at least to any substantial degree) to a temperature or temperatures below the stretch blow moulding temperature for at least the barrel region thereof to be stretch inflated, in a second mould assembly, stretch blowing the barrel region of the preform to define said bottle, wherein said preform after creation in said first mould assembly is manoeuvred by said neck and/or said handle by part of said first mould assembly into a two part blow mould for said barrel region and is indexed relative to the centre line thereof by reference to the handle, said two part blow mould (plus its blow nozzle) and said part of o. first mould assembly form at least part of said second mould assembly, and (ii) in the stretch blow moulding step, means for a deflecting the tang or extremity of the handle inwardly towards the remainder of the preform for a sufficient period and in such a way as to enable a better wrap around of the distal regions of the tang or said extremity by the body of the bottle or container being blown from said barrel region, where by presenting the distal region of the handle more inwardly it encounters sooner the plastics material being blown which is both thicker at that position H: \paulad\Keep\speci\51272-96 CARTER HOLT HARVEY LTD-AMEND.doc 27/04/00 19 and hotter.

2. A method of claim 1 wherein the part lines of those parts of the first mould assembly and those parts of the second mould assembly for said barrel region are substantially coincident.

3- A method of claim 2 wherein said substantially coincident part lines are in a plane or planes that include said handle.

4. A method of any one of claims 1 to 3 wherein said means for deflecting the tang or extremity inwardly is means reproducibly moveable to achieve said deflection for a sufficient period of time yet to move so as not to substantially (if at all) interfere with the said wrap around.

5. A method of claim 4 wherein said means is a pivotal member actuated by a reciprocating member such a .pneumatic, hydraulic or solenoidal member.

6. A method of claim 5 wherein said pivotal member is pivoted from a pivot axis which is substantially 25 perpendicular to the general longitudinal axis of the preform and is (with respect to radial projections from the preform) not closer to the neck region of the preform than said distal end of the tang region of said handle. A blow moulded PET container (or a container of a plastics material having similar characteristics to that of a biaxially oriented PET insofar as moulding requirements are concerned) that has been blown according to a method of any one of claims 1 to 6. H:\paulad\Keep\speci\51272-96 CARTER HOLT HARVEY LTD-AMEND.doc 27/04/00