GB2600232A

GB2600232A - An improved vessel and method of manufacture thereof

Info

Publication number: GB2600232A
Application number: GB2112640.4A
Authority: GB
Inventors: Andrew Cook Robert
Original assignee: Bodypak Ltd
Current assignee: Bodypak Ltd
Priority date: 2020-09-09
Filing date: 2021-09-06
Publication date: 2022-04-27
Also published as: GB202112640D0; GB202014188D0

Abstract

The vessel comprises a container 161 and a closure means 162, the container and the closure means being linked by a connector 163, the injection stretch blow moulding method comprises the steps of selecting a first mould section having a plurality of linked recesses (151, 152, 153, fig 14), including a container recess, said container recess including a pressure inlet (154, fig 14), selecting a second mould section and urging the first and second mould sections together such that the second mould section co-operates with the recesses of the first mould section to form one or more mould cavities, with each mould cavity corresponding to a recess in the first mould section. Thermoplastic material defines an internal volume of the container and has a single pressurising aperture enabling pressurising gas to be introduced into the internal volume, via a blow pin 167 into the aperture, to inflate the thermoplastic material. The pressurising means may comprise stretch rod (188, fig 19). The thermoplastic material may be in the form of a parison, which may be expanded into a first forming volume to form a pre-form material. The material may be a recycled grade.

Description

io An Improved Vessel and Method of Manufacture Thereof

Field of the Invention

The present invention relates to a one-piece vessel, including a container portion and closure member, and a method of manufacturing the same. The vessel can be formed of recyclable material allowing the entire vessel to be reprocessed following use and minimising materials used.

Background to the Invention

The problems caused by plastics materials in the environment are of increasing concern. Firstly, there is the problem that the raw material from which a plastic is formed is usually a fossil fuel which constitutes a finite resource. Also, in recent years it has become apparent that plastics materials are almost universally distributed throughout the ecosystem, with whole articles and particulates formed of plastics materials being found widely and in large masses in the marine environment: even at considerable ocean depths and within the bodies of marine animals. /5

Secondly, most plastics materials have a long degradation half-life in the environment, so that they remain a problem for decades and possibly centuries.

Attempts have been made recently to reduce the amount of non-biodegradable 5 plastics materials used by industry, or at least to minimise their use to re-usable articles. This often involves substitution of the plastics material in all or part of the article being manufactured by a recyclable material. This can either be by using a glass or metal, especially where the article is for re-use. Alternatively, biodegradable plastics are instead utilised. The present invention is intended for io use primarily in producing vessels formed of a biodegradable material, although the method can also be used with non-biodegradable materials.

A further aspect in the manufacture of vessels is that these are usually made of two parts: a container section in which a liquid is retained, and a closure means.

is This is wasteful of time and energy and it would be advantageous if the container and closure means were formed attached to each other, and particularly in a single step process. Although this can be achieved for certain configurations of container, the shapes produced are not generally useful in forming a conventional vessel in which the main body of the container is at least as wide as the neck out of which zo the contained liquid is poured. The reason for this is that the tooling required needs, following forming of the container, to be withdrawn without damaging the container: something hitherto not achievable. A typical example of such a prior art vessel is shown in Figure 1. Here, a container 10 has a container body 11 in which liquid is retained. A cap 12 fits about the neck 13 of the container 10 and is attached thereto by means of the thread able engagement of the internal screw thread 14 of the cap 12 with the external screw thread 15 on the neck 13 of the container 10.

Figure 2 shows the difficulty of forming the container and cap as a single component in the embodiment of Figure 1 by means of a single moulding process.

The diameter OB of the part of the metal moulding tool 20 required to give the container body 21 its shape is greater than that of the diameter OA used to form the neck 22 and so the moulding tool 20 cannot be withdrawn from the container body 21 without making a cut in the container body 21. Additionally, the problem remains of forming an attached cap as part of a vessel made by the common blow-moulding technique.

It is an object of the current invention to provide a single component vessel having a container body and a closure means and a method of manufacturing the same which addresses the above problems.

io Summary of the Invention

According to a first aspect of the invention, there is provided a method of is manufacture of a single-piece vessel, the vessel comprising a container and a closure means, the container and the closure means being linked by a connector; the method comprising the steps of selecting a first mould section, the first mould section haying a plurality of linked recesses, including a container recess, said container recess including a pressure inlet, selecting a second mould section and zo urging the first and second mould sections together such that the second mould section co-operates with the recesses of the first mould section to form one or more mould cavities, each mould cavity corresponding to a recess in the first mould section, securing the first and second mould sections together such that the container recess contains a thermoplastic material, the thermoplastic material zs defining an internal volume and having a single pressurising aperture enabling pressurising gas to be introduced into the internal volume, introducing a pressurising means via a blow pin into the aperture, pressurising the internal volume with the pressurising gas, to inflate the thermoplastic material, separating the first and second mould sections.

The method allows a single piece container to be manufactured more easily, in a single step, and with less waste and using less energy. The manufacture can therefore be carried out in fewer steps and requires a lower floorspace for the manufacture, thus saving manufacturing costs. The capital costs required for machinery are also less, as the method can be performed in a single piece of machinery and tooling.

Preferably, inflation continues until the thermoplastic material has been urged against the walls of the mould cavity. This allows a bespoke shape to be provided to the container.

Optionally, the pressurising means comprises a forming element housing an axially movable stretch rod, the movement extending the stretch rod from a first forming element-engaging position to an extended position in which a first end of the stretch rod extends beyond the forming element.

/5 Preferably, movement of the stretch rod from the first forming element-engaging position to a spaced engagement produces a fluid passage between the forming element housing and the stretch rod, the pressurising gas entering the internal volume via the fluid passage. The combination of pressurising supply and forming tool in one element simplifies manufacture.

Optionally, the first end of the stretch rod has a generally spherical configuration which minimises stress imparted to the thermoplastic material being shaped.

Preferably, the axial movement of the stretch rod pushes against the thermoplastic 25 material causing the thermoplastic material to stretch. Including this step, allows some preforming to be carried out before the inflation phase.

Preferably, the thermoplastic material is heated to increase the fluidity of the thermoplastic material prior to insertion into the container recess which facilitates 30 the forming of the material and minimises the risk of cracking of the material.

Preferably, the thermoplastic material is in the form of a parison, the parison being placed on the first mould section such that each recess is covered by the parison, the first and second mould sections being secured together causing one open end of the parison to be closed. The use of the parison facilitates pressuring the internal volume of the thermoplastic material. Further preferably, the parison is heated such that it is softened, prior to being placed on the first mould section, which facilitates the forming of the material and minimises the risk of cracking of the material.

Conveniently, in an injection blow-moulding process, the thermoplastic material is first expanded into a first forming volume to form a pre-form material, said pre-form thermoplastic material subsequently being transferred into the container recess to io be further expanded against the walls of the container recess. The injection blow moulding process has a number of advantages over extrusion blow moulding, for example wastage, and types of components which can be provided.

Preferably, the material from which the parison is formed is selected from a is polymeric plastics materials such as a polyhydroxyalkanoate (PHA) and polylactic acid (PLA), polypropylenes (PP), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), polyethylene terephthalate (PETE). Further preferably, the material is a recycled grade to reduce the environmental load of the method.

Optionally any flashings are removed and can be reused in the method.

According to a further aspect of the invention, there is provided a vessel formed in accordance with the method of manufacture of the first aspect.

Brief Description of the Drawings

The invention is now described with respect to the accompanying drawings which 30 show by way of example only, five embodiments of a vessel. In the drawings:

Figure 1 illustrates a prior art vessel;

Figure 2 illustrates a moulding tool required to form the vessel of Figure 1; Figure 3 illustrates a first embodiment of a vessel in accordance with the invention; Figure 4 illustrates in more detail the closure means of the cap of Figure 3; Figure 5 illustrates a second embodiment of a vessel in accordance with the invention; Figure 6 is a side view of the embodiment of Figure 5; Figure 7 illustrates a third embodiment of a vessel in accordance with the invention; Figure 8 illustrates a second view of the third embodiment with the detachment of the base area; Figure 9 illustrates a fourth embodiment of a vessel in accordance with the io invention; Figure 10 is an enlarged sectional view of the closure means of the cap of Figure 9; Figure 11 illustrates a fifth embodiment of vessel including a closure means; Figure 12 illustrates an embodiment of closure means; is Figure 13 illustrates a further embodiment of closure means; Figures 14-16 illustrate a first method of forming a one-piece container; Figure 17 illustrates a bottle formed using the method of Figures 14-16; Figures 18-20 illustrate formation of a vessel by injection stretch blow-moulding; Figure 21 illustrates a vessel formed using the method of Figures 18 -20.

zo Figures 22-24 illustrate formation of a vessel by injection blow moulding; and Figure 25 illustrates a vessel formed using the method of figures 22-24

Detailed Description of the Invention

The advantages of forming vessels from a plastics material which are recyclable is well appreciated in the art. To this end there is a continuing drive to develop and utilise recyclable polymeric materials which can be readily formed using conventional processing methodology such as extrusion blow-moulding, injection moulding, injection blow-moulding, injection stretch blow-moulding etc. or combinations thereof into vessels having the required 3-D shape. It would be further advantageous if a vessel were provided as a single piece able to be formed using the above techniques. Currently the container body and the closure means are manufactured separately, and subsequently brought together to make a closable vessel. There are however difficulties in carrying out the manufacture of a single-piece vessel due to the need to remove the mould tools from the finished article, without causing damage to the article as outlined above.

Further, prior designs of components with an integral stopper are produced either with an open end that has to be sealed, or the container area under the stopper element is internally smaller in size than the stopper internal area, allowing the io removal of tooling cores through the stopper element. This is a limiting factor to container shape on prior designs. The method as described below permits much more design freedom. The sealed container shape under the stopper element can be larger, as no internal tooling cores that produce the container area have to exit through the internal area of the stopper element.

The present invention contemplates an improved method of manufacture of a vessel which allows the vessel to be formed of a continuous, single piece of material. Additionally, the invention also contemplates a one-piece vessel formed in a single moulding step.

Turning to Figures 3-25, these describe examples of vessels which can be formed in accordance with the current process. Although the invention is preferably carried out using biodegradable polymeric materials it will be recognised that even when using non-biodegradable plastics there will be advantages to the user and the environment in that a single-step manufacturing process is carried out with reduced costs and energy usage. As examples of polymeric plastics materials which are suitable for use in the herein described method are biopolymers such as polyhydroxyalkanoates (PHA) and polylactic acid (PLA). Additionally, polypropylenes (PP), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (H DP E), polyethylene terephthalate (PETE) can be used. Where suitable, recycled grades of the above materials can be utilised.

In Figures 3 and 4, a first embodiment of a vessel is shown having a bottle 30 comprising a container body 31 and including an integral cap or lid 32. The bottle 30 can be formed by an extrusion blow-moulding process described below. The container body 31 is linked to a neck 34 by means of a shoulder 40. The neck 34 also supports the cap 32, being linked thereto by a strap 33. The strap 33 is flexible allowing the cap 32 to be fitted over the neck 34 to close the container body 31 when required and as shown in Figure 4. The open configuration of Figure 3 allows the container body 31 to be filled or for the contents to be removed as desired. In io order to close the container body 31, the cap 32 is provided with a circumferentially deployed channel 38 on one of the faces of the cap 32. The channel 38 is defined by the channel walls 39. The channel 38 in Figure 4 receives the wall 36 of the neck 34, with the wall 34 frictionally engaging the channel walls 39 thereby resisting removal of the cap 32 from the neck 34 and so reducing the chance of accidental is spillage of the contents. To assist the user in removing the cap 32 from the neck 34, the cap 32 includes a tab 37 against which the user can push to open the container 31.

In Figures 5 and 6, a similar arrangement is shown for a second embodiment of zo vessel which can be produced using an extrusion blow-moulding process. The vessel includes a tube, generally referenced 50. The tube 50 includes a tubular body 51 which is linked to a neck 56 via a shoulder 58. It can be seen that the distal end of the tubular body 51 has a V-shaped configuration formed by lower surfaces 57a, 57b, which surfaces are formed on sealing the distal end of the tubular body 51. Other configurations, known in the art, can be induced on the tubular body on sealing as required by the designer. The neck 56 is linked to a cap 52 by a flexible strap 53, which as in the first embodiment allows the cap 52 to be moved to close the tube 51 and still remain connected to the neck 56, as shown in Figure 6. The cap 52 fits to the neck 56 by means of a plug seal with the cap 52 forming a seal against the external diameter of the neck extension 54. The open configuration shown in Figure 5 allows the tubular body 51 to be filled or for the contents to be removed as desired. In order to close the tubular body 51, the cap 52 is provided with a circumferentially deployed channel (not illustrated) on one of the faces of the cap 52. The extension 54 has a chamfered upper surface 55 which facilitates fitment of the cap 52 to the closed position shown in Figure 6.

Figure 7 shows a third embodiment of vessel of the tubular type shown in Figures 5 and 6. The vessel is again produced by an extrusion blow-moulding process in a single moulding tool. In this embodiment, the vessel is first produced as a bottle similarly to the first embodiment, but subsequently converted to a tubular embodiment. So, the vessel is shown having a bottle 70 comprising a container 71 io and including an integral cap 72. The bottle 70 can be formed by an extrusion blow-moulding process described below. The container 71 is linked to a neck 74 by means of a shoulder 81. The neck 74 also supports the cap 72, being linked thereto by a strap 73. The strap 73 is flexible allowing the cap 72 to be fitted over the neck 74 to close the container 71 when required, . In order to close the is container 71, the cap and the neck 74 are configured as for the embodiment shown in Figures 5 and 6 in that the neck 74 has an extension 75 whose upper surface 76 is chamfered. It will also be recognised that the closure means can be as shown in the embodiment of Figures 3 and 4.

zo The container 71 as produced above is shown as being converted to a tube through removal of a lower portion (see Figure 8). This allows the vessel to be filled through the open base thus created, with the opening formed subsequently being sealed. The container 71 is produced with a V-form 77 as part of the moulding process. After the component has been produced as a vessel, the base area 78 below the zs V-form 77 has to be detached. This can be achieved through an inbuilt cutting device 79 in the mould tool, alternatively the component can be removed from the mould tool and the base area 78 below the V-form 77 can be removed by an ancillary cutting device. The removed base can then be reground into pellet form to be re-used.

Figures 9 and 10 illustrate a further embodiment of vessel comprising a bottle 90. The vessel as illustrated in Figure 9 can be formed by an injection process such as, injection blow-moulding and injection stretch blow-moulding. Where injection blow-moulding or injection stretch blow-moulding are used the component is formed in two stages in which in the first stage, the neck and lid/stopper elements are produced at an injection moulding station The lower portion of the vessel is then produced at a second blowing station.

The vessel shown in Figure 9 is similar to that illustrated in the above embodiments in that the vessel comprises a bottle 90 including also a container 91 and including an integral cap 92. The container 91 is linked to a neck 95 by means of a shoulder.

io The neck 95 also supports the cap or lid 92, being linked thereto by a strap 93. The strap 93 is flexible allowing the cap 92 to be fitted over the neck 95 to close the container 91 when required. In order to close the container 91, the cap 92 and the neck 95 are configured as for the embodiment shown in Figures 5 and 6 in that the neck 95 has an extension 98. A finger recess 96 allows a user to more easily lift is off the lid from the closed to the open position. To assist in retaining the lid in the closed position and also to provide the user with an audible click when opening and closing the lid 92, two lugs are formed: the first lug 97 on the neck 95 and the second lug 100 (see Figure 10) within the circumferential channel 101 in the lid 92. On closing the lid 92 therefore, the user presses down for example on the upper zo surface 99 of the lid 92 until the lugs 97, 100 slide over each other. The plasticity of the material from which the vessel is formed assists this action. Once the lid 92 is in the closed position, frictional engagement between the inner facing wall of the channel 101 with the outer face 102 of the extension 98 also aid in keeping the lid 92 in the closed position. The exterior surface of plug seal 131 frictionally engages zs with surface 133 and provides a fluid-proof seal. It will also be recognised that the closure means can alternatively be as shown in the above embodiments.

In the vessel of Figure 11, a combined jar and lid/stopper is shown. The vessel can be formed by an injection process such as, injection blow-moulding and injection stretch blow-moulding. The components of the vessel are similar to the above embodiments in that the vessel comprises a jar 110 including also a container 111 and including an integral cap 112. Extending from the upper circumferential rim of the container 111 is an extension 120. The cap 112 is linked directly to the container 111, being linked thereto by a strap 113. The strap 113 is flexible allowing the cap 112 to be fitted about the extension 120 and to frictionally engage the outer surface of the extension 120 of the neck 95 to close the container 91 when required and as shown in Figure 10. A finger recess 116 allows a user to more easily lift off the lid from the closed to the open position. To assist in retaining the lid in the closed position and also to provide the user with an audible click when opening and closing the lid 112, two lugs are formed: the first lug 117 on the outer surface of the extension 120 and the second, 118 within the circumferential channel io in the lid 112. On closing the lid 112 therefore, the user presses down for example on the upper surface of the lid 112 until the lugs 117, 118 slide over each other. The plasticity of the material from which the vessel is formed assists this action. Once the lid 112 is in the closed position, frictional engagement between the walls of the channel formed between the outer wall of the lid 112 and the circumferential is wall 119 with the extension 120 also aids in keeping the lid 112 in the closed position. The exterior surface of plug seal 131 frictionally engages with surface 133 and provides a fluid-proof seal. It will also be recognised that the closure means can alternatively be as shown in the above embodiments.

zo In a first sealing option between a lid and a container shown in Figure 12, a plug seal is shown between a container 137 and a lid. The container 137 has an inner bore 134 defined by the surface 133 of the wall of the container 137. The lid has a circumferential channel 138 which in sealing the vessel houses the wall of the container 137. The inner wall 132 of the channel has a chamfered end-surface 135 zs to aid in placing the lid about the wall. Once in position, the surface 131 frictionally engages the surface 133 of the container as a sealing engagement and to resist opening of the closed vessel. A tab 136 aids the opening process when required.

In the second sealing option of Figure 13, the lid 140 has an inner, circumferential 30 sealing surface 139 which in the closed position of the vessel, frictionally engages the surface 141 on the container. A further sealing engagement is provided between the surfaces 143 and 145 on the lid and container respectively. As with earlier embodiments, a tab 144 aids the user in opening the vessel. The upper edge of the extension 142 on the container is chamfered to aid engagement with the lid.

Turning now to Figures 14 -17, these illustrate a method of manufacture of the above-disclosed vessels. In Figure 14, one half of an extrusion blow-mould tool 150 is shown. The mould comprises recesses 151, 152, 153 in which the container, cap and strap elements of a vessel are formed. The shape of the recesses provides the 3-D shape of the final formed element. The recess 151 is a container recess io and includes a pressure inlet 154, enabling a pressurising means such as compressed air to be applied. The inlet 154 therefore enables a supply and connection for compressed air to connected to the internal volume of the combined blow-mould tools. The surface 155 engages with the second half of the blow-moulding tool when the two halves are brought together during the moulding is process. Engagement between the surface 155 and the corresponding surface on the other tool should not be fluid tight as a gap needs to be allowed for the presence of the parison 156 introduced therebetween, which can be in the direction shown by the arrows A. zo The parison 156 is placed so as to extend over the recesses 151, 152, and 153 and also the surface 155. The parison 156 is a tubular structure formed of the polymeric material from which the vessel is to be formed. Prior to its introduction, the parison 156 is heated to soften the polymeric material and allowing the material to flow more freely.

The second half of the mould tool is urged against the first half so that the corresponding recesses form the appropriate mould shape. In carrying out this step, a portion of the parison 156 is crushed between the surfaces 155 (see Figure 16). This acts to form by pressure the cap and strap of the vessel being formed.

A blow pin 167 is introduced via the inlet 154 and enters the inside of the tubular parison 156. The inside of the parison 156 is pressurised via the introduction of compressed air conveyed to the blow pin 167 via a tube 165 and connector 166, and the parison 156 inflates against the surface of the mould 151 to produce the container shape. The polymeric material of the parison 156 in the mould parts 152, 153 is formed by compression into the shape required by the pressure applied to the mould parts. The component parts of the vessel, the container 161, the cap 162, the strap 163, and the strap 164 are thereby formed, to produce the final vessel shown in Figure 17. The material of the parison 156 which during the process is trapped between the flat surfaces of the mould tools, and remains adhered to the formed container 160 as flashings can be removed by an appropriate tool and recycled for further usage.

In Figures 18 -21, the method of manufacture of a vessel by injection stretch blow-moulding is illustrated.

In Figure 18 the initial stage of the injection stretch blow manufacturing process is can be seen. Injection stretch blow moulding, as illustrated here, provides a more even heating and cooling of the plastics material compared with injection blow moulding, thus providing a more consistent thickness of material. At this stage the component is produced by injecting a molten plastics material into the mould tool. The vessel shape 182a is formed in the mould cavity 180. This is not the finished zo vessel shape; it is a stage one shape that will later be converted into the final vessel shape. Above the stage one vessel shape 182a is the vessel closure area 182b. This area 182b, the lid area 187 and the adjoining hinge are fully formed at this stage, with the shape being produced in the carrier plates 181 of the tooling part. The inside form of the component is produced by the tooling parts 185a (lid core) 185b (preform core) and 185c (top area cavity). Once the component has been fully formed, the machine opens the tooling. First the mould cavity 180 separates from the carrier plate 181, then the internal tooling parts 185a, 185b & 185c retract, followed by the plates 183 & 184, leaving the pre-formed component contained within the carrier plate 181. The carrier plate 181 then transfers the component first through a conditioning station, where the vessel shape 182a can be exposed to external heat / internal cooling that can assist in influencing the even distribution of the vessel material in the following station. Following the conditioning stage, the carrier plates 181 transport the component to the stretch blow tooling station as shown in Figure 19.

In Figure 19 the stretching of the vessel and then inflation of the vessel with high pressure compressed air takes place. The component inside the carrier plates 181 is assembled into the blowing cavity 190. Following this, the stretch/blow assembly comprising a forming element 186 and a stretch rod 188 lower into the component with the tip 189 of the stretch rod making contact with the end of the component, and the clamping plate 191 holding the top of the component in position.

Figure 20 then shows the stretch/blowing stage. The stretch rod 188 lowers and stretches the pre-formed vessel area down towards the base area of the container cavity. This separates the stretch rod 188 from the forming element 186 and opens up a fluid channel therebetween. Next, high pressure compressed air, entering via is the fluid channel thereby formed, inflates the vessel into the shape of the container 192. Finally, the air is exhausted and the stretch rod 188 retracted, the tooling then separates to leave the finished component again contained within the carrier plates 181. The carrier plates 181 then transport the finished component to the discharge area of the machine, where they open to eject the finished component from the zo machine as per Figure 21.

In Figures 22 -24, the method of manufacture of a vessel by injection blow-moulding is illustrated.

zs In Figure 22 the initial stage of the injection blow manufacturing process can be seen. At this stage the component is produced by injecting molten plastic material into the mould tool. The vessel shape 182a is formed in the mould cavity 201. This is not the finished vessel shape; it is a stage one shape that will later be converted into the final vessel shape. Above the stage one vessel shape 182a is the vessel closure area 182b. This area, the lid area 187 and adjoining hinge are fully formed at this stage. The inside form of the component is produced by the tooling parts 202a (lid core) 202b (lid sleeve) 203a (preform core), 203b (core tip) and 204 (top area cavity). Once the component has been fully formed, the machine opens the tooling, with the component remaining on the preform core and tip 203a & 203b.

The component is then transferred on the preform core and tip and presented into 5 the blow mould tool 205 as shown in Figure 23. The lid area of the component is fully formed, and locates in an open space 206 in the blow mould tool, above the area where the vessel part of the component will be changed.

Figure 24 shows the next stage of the process. With the two blow mould tool halves io closed around the component, the core tip 203b moves forward to allow high pressure compressed air to pass between the preform core and the tips 203a & 203b. The high-pressure air inflates the vessel shape into the shape of the container 192. Finally, the air is exhausted and the core tip 203b retracted, the tooling then separates to leave the finished component again remaining on the /5 preform core and tips 203a & 203b. The component is then transferred on the preform core and tips to the discharge area of the machine, where the finished component is stripped off the core from the machine as per Figure 25.

Claims

Claims 1 A method of manufacture of a single-piece vessel, the vessel comprising a container and a closure means, the container and the closure means being linked by a connector; the method comprising the steps of selecting a first mould section, the first mould section having a plurality of linked recesses, including a container recess, said container recess including a pressure inlet, selecting a second mould section and urging the first and second mould io sections together such that the second mould section co-operates with the recesses of the first mould section to form one or more mould cavities, each mould cavity corresponding to a recess in the first mould section, securing the first and second mould sections together such that the container recess contains a thermoplastic material, the thermoplastic /5 material defining an internal volume and having a single pressurising aperture enabling pressurising gas to be introduced into the internal volume, introducing a pressurising means via a blow pin into the aperture, pressurising the internal volume with the pressurising gas, to inflate the thermoplastic material, separating the first and second mould sections.
2. A method according to claim 1, wherein inflation continues until the thermoplastic material has been urged against the walls of the mould cavity.
3 A method according to Claim 1 or Claim 2, wherein the pressurising means comprises a forming element housing an axially movable stretch rod, the movement extending the stretch rod from a first forming element-engaging position to an extended position in which a first end of the stretch rod extends beyond the forming element.
4. A method according to Claim 3, wherein movement of the stretch rod from the first forming element-engaging position to a spaced engagement produces a fluid passage between the forming element housing and the stretch rod, the pressurising gas entering the internal volume via the fluid passage
5. A method according to Claim 3 or Claim 4, wherein the first end of the stretch rod has a generally spherical configuration.
6. A method according to Claims 3 to 5, wherein the axial movement of the stretch rod pushes against the thermoplastic material causing the thermoplastic material to stretch.
7. A method according to any preceding claim, wherein the thermoplastic material is heated to increase the fluidity of the thermoplastic material prior to insertion into the container recess.
8 A method according to any preceding Claim, wherein the thermoplastic material is in the form of a parison, the parison being placed on the first mould section such that each recess is covered by the parison, the first and second mould sections being secured together causing one open end of the parison to be closed.
9. A method according to Claim 9, wherein the parison is heated such that it is softened, prior to being placed on the first mould section.
10.A method according to Claims 1 -7, wherein the thermoplastic material is first expanded into a first forming volume to form a pre-form material, said pre-form thermoplastic material subsequently being transferred into the container recess to be further expanded against the walls of the container recess.
11.A method according to any preceding Claim, wherein the material from which the parison is formed is selected from a polymeric plastics materials such as a polyhydroxyalkanoate (PHA) and polylactic acid (PLA), polypropylenes (PP), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), polyethylene terephthalate (PETE).
12.A method according to Claim 11, wherein the material is a recycled grade.
13.A method according to any preceding claim, wherein a blow pin is introduced into the pressurising aperture, entering the internal volume of the tubular parison
14.A method according to any preceding claim, wherein any flashings are removed.
15.A vessel formed in accordance with the method of manufacture of Claims 1 -14.