ES2962342T3 - Improvements in double wall containers - Google Patents

Abstract

A method and apparatus for forming double-walled containers having the structure of two adjacent and integrally connected containers extending in the same direction with an air space between them, stretch-blow molded as individual bodies from thermoplastic material , and suitable for mass training. -production. A thermoplastic tubular blank is formed and then thermally conditioned. The heat-conditioned tubular blank is then mechanically stretched longitudinally and blown outwardly formed by gas pressure to conformably and stretchably adopt the tubular blank into the shape of a first set of shaped mold cavities. double container to form a first stretch blow molding. container integrally connected to a second container, both containers extending in opposite directions. Additional thermal conditioning is then applied to further condition, as necessary, the second stretch blow molded container and, if considered an advantage, at least part of the first container. At least one profiled reversing piston and a second set of dual container-shaped mold cavities are then provided along with one or more wall stability devices applied to at least part of the wall surface(s) of one or both of the two integrally connected sections. blow molded containers, so that the second side wall(s) of the container can be at least partially inverted from the inside out, while at the same time the second bottom wall(s) of the container at least substantially is not inverted, so that the second container becomes a substantially mirror image inverted second container extending in the same direction as the first container, and an air space is formed between the first container and the second container. (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Improvements in double wall containers

field of invention

This invention relates to a method and apparatus for the stretch blow molding of double-walled containers, formed as individual bodies from tubular thermoplastic resin blanks, and having the structure of two adjacent and integrally connected containers that extend in the same direction and with an air gap between them, and more specifically, to a method and apparatus suitable for high-speed mass production, producing integral double-walled containers with very thin walls and with very thin wall thicknesses. uniforms.

Background of the invention

According to Wikipedia, a container is "a basic tool consisting of any device that creates a partially or fully enclosed space that can be used to contain, store, and transport objects or materials."

As used herein, the term container refers to any receptacle of hollow or concave internal structure that can be used to contain liquid and/or solid contents, whether or not intended by design to contain such contents, and includes at least; a mouth that opens substantially on the radial axis of the container, at least one side wall arranged parallel and/or at an angle with respect to the longitudinal axis of the container, and a bottom wall substantially on the radial axis of the container, wherein the wall The bottom may be a completely closed bottom wall forming the bottom end of a completely closed container, or it may be a partially closed bottom wall forming the bottom end of a partially closed container. A partially closed bottom wall is one in which the surface area of the bottom wall is substantially greater than the surface area of the average side wall measured in the same radial plane. At a minimum, a partially closed bottom wall may be a thickened lip section at the end of a side wall, such as mechanical connection and/or sealing features in a tubular blank.

As used herein, a container may be a beaker, a bottle, a bowl, a canteen, a stopper, a jug, a cardboard box, a cover, a cup, a fast food container, a container. of food, a glass, a bell, a lid, a bowl, plate, pot or glass, or any other derivative of a container that denotes a partially or totally closed space capable of containing liquid and/or solid contents.

As used herein, the term tubular denotes an object substantially similar in shape to a pipe or tube, where the object is hollow in nature and substantially cylindrical in shape, however, this does not mean by definition that a tubular object be necessarily round or circular. A tubular object may have any shape or cross section as necessary for any specific application and/or container design, including, but not limited to, round, circular, ovoid, triangular, square, rectangular, or any combination of geometric shapes and/or non-geometric or shapes thereof radially and/or longitudinally.

The term "double-walled container having the structure of two adjacent and integrally connected containers extending in the same direction with an air gap between them and formed as a single body", as used herein, may also be substituted for "integral double-walled container."

The term "dual container having the structure of two integrally connected containers extending in opposite directions and formed as a single body", as used herein, may equally be replaced by "integral dual container".

The term blowing ratio, as used herein, may also be replaced by expansion ratio and denotes the relationship between any given dimensional size of a tubular blank (or tubular blank) before blow forming and the size respective dimensional of the container once formed by blowing.

The term "mold cavity set" as used herein denotes a mold that typically includes two substantially similar mold halves, however, as will be apparent to those skilled in the art, this should not be considered a limitation of a mold cavity assembly to only two mold components. There may be any number of integral and/or separate parts that form a set of mold cavities.

Every year countless low-cost containers that are suitable for mass production are manufactured around the world. For low-cost containers mass-produced by blow molding from thermoplastic material, issues related to low-cost production include, but are not limited to: • Low-cost thermoformable plastic resin,

Thin wall sections/light empty weight,

High production speed,

Small production line size to allow for small cell production facilities that can be located adjacent to distribution centers, thereby minimizing logistics costs.

Production method based on primary processes,

High degree of recyclability,

Maximize stacking capacity to minimize logistics and storage costs.

Small number of subcomponents,

Small number of production processes.

Today, almost all mass-produced containers are single-walled in nature. The primary reasons are that current production processes are incapable of manufacturing integral double-walled containers, or any production methods currently used that may be capable of producing integral double-walled containers result in commercially prohibitive unit production costs.

As an example; A current method of producing thermoplastic cups is by thermoforming, where pre-processed flat sheets of thermoplastic material are heated to the softening temperature of the thermoplastic resin, but generally not above the melting temperature, and then gas pressure is applied. and/or mechanical stretching to thermally form the flat sheet into container-shaped mold cavities. Using this method, single-wall structures can be easily formed from flat sheets, however, no known variation of the thermoforming process from flat sheets can viably create complete double-wall structures as this would require that at less of the wall structure will effectively contract rather than stretch during thermoforming and this is contrary to the basis of the production method.

As another example, some bottle-shaped containers are produced by extrusion blow molding, where tubes of thermoplastic material that are above their melting temperature (molten) are extruded between sets of container-shaped mold cavities and Then, while still in a molten state, gas pressure is applied to thermally form the molten thermoplastic resin in the cavities. The problems associated with mass production with this process are that the extrusion of the molten tube is very slow and therefore high production rates cannot be achieved, and while in a molten state there is a practical limit as to how thin the walls of the final container can be. Normally, in this process the wall thicknesses are substantially greater than 1 mm, which in the case of mass-produced containers represents a prohibitive commercial cost.

There are a number of market-driven reasons for an integral double-walled container with the structure of two integrally connected and adjacent containers with an air gap between them and formed as a single body, including, but not limited to:

• The formation of a fully recyclable coffee cup,

• The formation of a cold cup that does not form condensation on the outer walls,

• The formation of a cold cup that can extend the shelf life of the drink, and

• The formation of a container that prolongs the time its contents remain hot.

Using as an example the cup genre within the inner container sector, and apart from the widely used solution for coffee cups of a separate thermal sleeve to protect the user from burning their hand, the typical solution that a user resorts to When addressing any of these needs is to place a cup inside a cup to form a "double-walled container with an air gap." From a mass production point of view, this "cup within a cup" solution, like the separate thermal sleeve for the coffee cup, adds significant additional cost and leads to greater waste, which is counterproductive to any recycling requirements.

For mass production and in all types of containers, a cost-effective solution lies in the ability to form a container within a container, structured so that the two containers form a single body, and by which a gap of air between the two integral and adjacent containers.

Brief description of the previous technique.

The U.S. patent No. US 3,182,842A teaches a double-walled container structure produced by extrusion-blow molding, with various production steps taught, all of which occur while the container remains in a molten state. Only when the full, complete double-walled container has been formed is the container allowed to cool enough to allow the thermoplastic resin to fall below its melting temperature and therefore solidify.

As already noted, extrusion blow molding is typified by low production speeds and substantially thick-walled finished products and has rarely, if ever, as a process been able to produce low-cost mass-produced containers, however, This was the primary blow forming methodology for thermoplastics at the time this patent was filed in 1963. Over the following decades, significant advances have been made in blow forming production methods that are more suitable for wall structures. thin

The U.S. patent No. US 3,612,346 teaches a double-walled cup structure produced by thermoforming from a pre-processed flat sheet, wherein a portion of the flat sheet is integrally formed into a reversely tapered outer wall section that covers at least part of the cup section. central cup.

While this patent primarily teaches a reversely tapered outer double side wall section to assist with the stackability of vending machine cups, the patent shows a cup with a reversely tapered outer double side wall that extends downward beyond the cup wall. below the center section of the cup. As this patent is based on cups thermoformed from pre-processed flat sheets, it is unlikely that this cup image as shown could be produced as taught, since no known thermoplastic resin can be heat stretched in some areas under the application of heat and pressure (the center section of the cup) while at the same time heat shrinking in other areas (the reverse tapered outer wall). Even if such a thermoplastic resin existed, the inversely tapered double outer side wall would not have a uniform wall thickness as depicted, but rather would have a substantially graduated wall thickness, with the wall thickness increasing inversely as the radial diameter decreased; as the thinnest adjacent to the drinking rim of the cup and the thickest on the bottom rim.

In the unlikely event that a method of thermoforming this cup as taught could be achieved from a flat sheet, the resulting cup would be cost prohibitive as a mass produced container since thermoforming itself cannot form walls of ultra-thin cup and the graduated wall thickness of the reversely tapered double outer side wall would significantly impact the final empty weight of the cup and therefore the unit cost of the cup. As an example, a 500 ml single wall cup for fast food applications formed by thermoforming has a typical wall thickness on the order of 0.35 mm and a typical cup empty weight on the order of 13 grams. With the addition of an integral, reversely tapered, outer double side wall formed by shrink forming from an initial flat sheet, the probable empty weight of the cup would be at least twice the current typical weight of the cup.

The U.S. patent No. 3,969,060 teaches a method of blow molding bottles based on the deformation of a tubular piece of thermoplastic material. The stub is tubular in shape with a single open end and is manufactured using a separate injection molding process. At a later time and separate from the injection molding process, the tubular piece is thermally conditioned so that its temperature is in the thermal softening range but typically well below the melting temperature of the thermoplastic resin, and once conditioned thermally at the desired temperature, the tubular piece expands outward under mechanical and/or gas pressure to extensiblely assume the cavity configuration of a set of external mold cavities and thereby form a finished bottle product.

This process, first taught in approximately 1976, revolutionized the production of thin-walled bottles. When a thermoplastic resin needs to be above room temperature for thermoforming, it must also be subsequently cooled to near room temperature after forming and these heating and cooling times impact the overall production speed and therefore the the unit cost of the product. By blow forming well below the melting temperature of a thermoplastic resin, heating and cooling times are significantly reduced compared to extrusion blow molding, so overall production speed is significantly increased. Additionally, thermoplastic resins typically stretch more uniformly when below their melting temperature, so with the advent of this process reliable production of bottles with significantly thinner walls became possible. As an added bonus, the thinner the wall of the finished product, the faster the product can be cooled to near room temperature.

With the advent of this process, known as "stretch blow molding," the extrusion blow molding process virtually disappeared in relation to the mass production of bottle-shaped containers.

The U.S. patent No. 9,339,979 teaches a double-walled thermal barrier cup thermoformed as a single piece of thermoplastic material with at least one rib maintaining a partial space between the inner and outer walls, and with the cup formed having a sealed insulation space. While the cup forming process itself is not taught other than with reference to "thermoforming," the patent shows that the double-walled thermal barrier cup is formed from a tube with open first and second ends and It is formed by the application of heat, pressure and an external mold, and exhibits formed cups having wall thicknesses of approximately 0.35 mm.

It is well known to those skilled in the art that when a thermally softened (but not molten) thermoplastic resin is blow formed radially and longitudinally in a mold cavity, there is a practical limit as to the extent to which a resin can be stretched. reliable under the application of gas pressure, the practical limit of the blowing ratio being considered to be a 3-fold expansion ratio between the initial tubular blank before blow forming and the finished blow-formed product. It is also well known to those skilled in the art that prior to blow forming a thermally softened thermoplastic resin, it can be mechanically stretched longitudinally at a rate typically much greater than 3 times. This combination of mechanical stretching and then blow forming of thermally softened thermoplastic resin is the basis of today's production of thin-walled containers.

To achieve the production of very thin-walled containers, stretch blow molding is typically used instead of thermoforming. Stretch blow molding of a tubular blank to obtain a blow molded container is a combination of:

• Mechanical stretch in a longitudinal direction – defined herein as the longitudinal stretch ratio LS and calculated herein as L1/L0, where L1 is the stretched length of the tubular blank and L0 is the initial length of the workpiece tubular blank, and

• Gas pressure stretch in a longitudinal and/or radial direction - defined herein as the radial stretch ratio RS and calculated herein as R1/R0, where R1 is the circumference at any point after pressure stretching and R0 is the respective initial circumference of the tubular blank.

• RSmax is defined herein as the largest value of RS that occurs along the length of the tubular blank.

• These two ratios can then be combined herein into a general stretch blow molding ratio RL calculated as RS/LS, with RLmax being the maximum calculable RL at any point along the tubular blank, calculated herein such as RSmax/LS.

Mainly due to the limitations of the physical properties of thermoplastic resin, if RSmax significantly exceeds 3, then container rupture normally occurs during blow forming, and when there is mechanical stretching, LS is always greater than 1. Therefore , for viable blow forming of very thin-walled containers, RLmax should normally not exceed 3.

Nothing is taught in US 9,339,979 about mechanical stretching of the thermally softened tubular initial blank prior to blow forming, so, as taught, the LS ratio is 1. In the figures provided, the circumference of the tubular blank (represented by the tube-shaped pinch points on the two bottom walls of the cups) compared to the largest circumference in the blow-formed cup product (the transition region between the two integrally formed cup shapes) represents an RSmax considerably greater than 3. Therefore, it would be obvious to those versed in the art that the double cup shape as taught would be, at best, very impractical to blow molding because both RSmax and RLmax are significantly greater than 3, and even if it could be blow molded without a high breakage percentage, the resulting product as formed would not have the uniform wall thickness depicted. While some areas, such as the transition region, may exhibit thin-walled properties, in all likelihood other regions, such as the bottom and adjacent side walls, would be far from thin-walled in nature. Considering only that US 9,339,979 describes blow formed cups having a wall thickness of approximately 0.35 mm, the double wall thermal barrier cup as taught would be at least twice the weight of an existing single wall thermoformed cup of comparable volumetric capacity and would therefore be commercially cost-prohibitive as a mass-produced container.

Document US2009283608A1 discloses a method for producing a double-walled container having the structure of two adjacent and integrally connected containers extending in the same direction with an air gap between them according to the preamble of claim 1 and a corresponding molding apparatus by blowing and stretching to produce a mechanically inverted double-walled container with the structure of two adjacent and integrally connected containers extending in the same direction with an air gap between them.

Document JPS5175760A discloses another relevant method and apparatus for producing stackable bottles. JPS5175760A does not relate to stretch blow molding,

The object of the present invention is to overcome some of the disadvantages of forming integral double-walled containers with the frame or two adjacent and integrally connected containers with an air gap between them and formed as individual bodies so as to become commercially viable. as mass-produced thin-walled containers.

Summary of the invention

According to the present invention, there is provided a method according to claim 1 and an apparatus according to claim 19.

A tubular blank may have only one open end, in which case the first set of dual-container-shaped mold cavities may have at least two separate dual-container-shaped mold cavity halves that may each include a first container cavity recess with a mouth opening, side walls and a partially closed bottom wall and all may include small radius wall stiffening features and/or at least partial air gap sealing features, and a second recess cavity in the form of a smaller container with a mouth opening, side walls and a completely closed bottom wall and all may include small radius wall rigidity features and/or at least partial air gap sealing features, with the two bowl-shaped cavity recesses extending in opposite directions from each other and integrally connected.

A tubular blank may have a first and a second open end, in which case the first set of dual container-shaped mold cavities may instead include a first container cavity recess with a mouth opening, walls sides and a partially closed bottom wall and all may include small radius wall stiffening features and/or at least partial air gap sealing features, and a second smaller container cavity recess with a mouth opening, side walls and a partially closed bottom wall and may all include small radius wall stiffening features and/or at least partial air gap sealing features, with the two bowl-shaped cavity recesses extending in opposite directions between yes and integrally connected.

Whatever the format of the tubular blank, a second set of dual-vessel-shaped mold cavities may have two separate dual-vessel-shaped mold cavity halves that may each include at least one piston recess. profiled inversion, a first recess of the container cavity with a mouth opening, side walls and a partially closed bottom wall and all may include small radius wall stiffening features and/or air gap sealing features at least partial, and a second cavity recess in the form of a smaller container with a mouth opening, side walls and a partially closed bottom wall and all may include small radius wall stiffening features and/or gap sealing features. at least partial air, with the two container-shaped cavity recesses extending in opposite directions from each other and integrally connected, and may include one or more devices for thermal conditioning of the first and/or second smaller stretch blow molded container and may include pathways for interconnection with at least one source of sub-atmospheric air pressure.

Because the combination of the mechanical stretching phase before the blowing phase has an LS substantially greater than 1, the tubular blank has an RSmax substantially 3 or less, and the second inversion of the smaller container is assisted by the wall stability devices and profiled reversing pistons, an integral double-walled vessel having the structure of two adjacent and integrally connected vessels extending in the same direction with an air gap between them may be formed as a single body suitable for mass production. The air gap thus formed may be a partially sealed or open air gap.

Additional production steps can be added at any point in the sequence, including, but not limited to: • The use of wall stability devices and profiled reversing pistons to extensibly extend the length of the side wall of the second smaller container. invested,

• Cutting any part or parts of the integrally connected container and/or tubular blank by any method and for any reason,

• Convert any partially closed bottom wall to a completely closed bottom wall by any method and may result in the formation of a completely closed air gap,

• Further inversion of any feature or wall section in any integrally connected vessel by any method and for any reason may result in the formation of a partially or fully closed air gap,

• Adding an additional part or parts in any way to any of the integrally connected containers by any method and for any reason may result in the formation of a partially or completely closed air gap,

• Adding additional material or materials of any form, property or nature to the air gap by any method and for any reason, including improving thermal insulation,

• The application of additional shaping/forming methods to ensure that the second smaller inverted container fully assumes its final design shape/figure.

• Print on any surface of any of the integrally connected containers by any method.

As the thermally conditioned tubular blanks are stretched by mechanical and/or gas pressure devices to stretch form them into sets of dual vessel shaped mold cavities, at one or more locations they must;

• Be sufficiently mechanically fastened to allow mechanical stretching, and

• Be sufficiently sealed so that gas pressure can be applied inside.

All open ends of the tubular blank may have mechanical clamping features, and at least one open end of the tubular blank may have sealing clamping features. Typically, at least one open end of a tubular blank will be substantially round as this provides the most secure and efficient configuration for both mechanical and sealing joining. However, except at open ends, the circumferential shape of a tubular blank may be any combination of geometric and/or non-geometric shapes, or any change or changes in circumference, as intended by the design and with respect to expanding the tubular blank according to the final shape of the blow-formed container.

When a tubular blank is stretch blow molded in a set of dual container-shaped cavities, the higher the blow ratio, the more difficult it can be to achieve uniform wall thicknesses of the blown container. As will be obvious to those skilled in the art, substantially in the middle region of a tubular blank from which the main portion of a container is stretch blow molded, substantially uniform blow shaping is typically achieved and, therefore, fairly uniform container wall thicknesses in this area can be easily achieved. However, in the end regions of a tubular blank that typically form container mouth openings and bottom walls, the higher the blowing ratio, or in other words, the smaller the size of the initial tubular blank. With respect to the final container size, the more difficult it may be to achieve a substantially uniform wall thickness in mating areas of a container. Therefore, typically when the size of the tubular blank is substantially smaller than the final size of the container, thicker wall sections near the opening of the container mouth and below the container and thinner wall sections result. in the middle of the container.

For the production of many bottle items, this is not a problem; However, for mass-produced containers, non-uniformity of wall thickness directly translates into wasted material and therefore a commercially prohibitive unit cost of the product.

Ensuring that tubular blanks by design have an RSmax of substantially 3 or less:

• The tubular blanks thus have the thinnest possible wall thickness in relation to the final container to be stretched blow molded,

• The thickness of the tubular blank wall is further reduced by the mechanical stretching phase, and

• When the stretch-blow phase begins, the tubular blanks are stretched outward as uniformly as possible.

As a result of the rough tubular design, process apparatus and production steps as taught herein, an integral double-walled container can be stretch blow molded with the thinnest viable wall thickness and a high degree of uniformity of wall thickness, and thus an integral double-walled container can be formed that is very suitable for mass production. The intention is that the stretch blow mold method and apparatus achieve highly uniform average wall thicknesses significantly less than 0.35 mm, and preferably between 0.10 and 0.30 mm.

Considering the cost of thermoplastic resin and ease of recyclability, the preferred thermoplastic resin for use with this method and apparatus is polypropylene (PP); However, depending on the specific market application of the double-walled integral container, any suitable thermoplastic resin may equally be used.

A thermoplastic resin used by this method and apparatus may be oil-based or bio-based, clear/transparent, semi-transparent or opaque, of its natural resin color or of any color or combination of colors to suit an application, a single type of resin or a mixture of resin types, or any combination thereof.

The thermal conditioning of the tubular blank at the first thermal conditioning temperature and the second thermal conditioning temperature may be:

• An increase in temperature if, for example, tubular blanks and/or integral dual containers are formed remotely at any relevant stage in a double-walled integral container forming sequence and therefore need to be heated to reach a thermally conditioned temperature,

• A decrease in temperature if, for example, tubular blanks and/or integral dual containers are formed adjacent or integral to any relevant step in a double-walled integral container forming sequence and therefore need to be cooled down to the thermal conditioning temperature, • Any combination thereof.

Preferably, the first thermally conditioned temperature is on the order of 80 to 100 degrees Celsius and the second thermally conditioned temperature is on the order of 60 to 120 degrees Celsius. The first thermally conditioned temperature may be the same as the second thermally conditioned temperature, or both may have different thermally conditioned temperatures.

Thermal conditioning, whether an increase in temperature or a decrease in temperature, may equally be applied to any one or more parts or subparts of the apparatus, such as for example only:

• Applying cooling to one or more regions in a set of mold cavities to assist in returning a blow-formed integral dual container to substantially room temperature once a tubular blank has conformably and extensibly assumed the shape of a first dual vessel shaped mold cavity set,

• Apply cooling to a mechanical stretching device to counteract heat buildup in the mechanical stretching device that can lead to rupture of the thin-walled tubular blank during the mechanical stretching and/or blow forming phases. gas pressure.

Gas pressure blow forming may begin after completing the longitudinal mechanical stretching, or gas pressure blow forming may begin before completing the longitudinal mechanical stretching.

When containers are formed with very thin walls and a high degree of uniformity in wall thickness, the structural strength of the final container can be an issue. The geometrically simpler the curved or cylindrical wall shape in a container structure, typically the lower the wall stiffness and therefore the lower the container stiffness, such as with straight-sided bottle walls or conical cup walls that typically exhibit large radius curves radially and have a substantially linear shape longitudinally.

While the selection of thermoplastic resins can help with wall stiffness, typically the thermoplastic resins most applicable for integral double-walled containers, such as PP, have a lower rather than a higher stiffness. One way to increase wall stiffness without affecting the cost of the production part is to introduce additional small radius shapes or forms into the design of the wall section of the finished product radially and/or longitudinally.

As for the second smaller container, the requirement to invert this container from its stretch blow molded position extending in a direction opposite to the first container to a substantially mirror position in the interior and extending in the same direction as The first container preferably requires simple walls of large radius, as such wall shapes are easily invertible (such as, for example, inverting a plastic contact lens), since even when in a heat-softened state, the more complicated the the geometric figure/shape, the greater the difficulty of the investment. Therefore, in a second smaller vessel cavity recess, curved cavity walls composed of conical, cylindrical or high radius shape are preferred. While this may mean that a second smaller inverted container exhibits relatively low rigidity, it forms the inner container of an integral double-walled container structure and therefore has the primary function of containing liquid/solid contents, therefore, As with comparable container formats, such as a bag-in-a-box container, rigidity is of little importance.

As far as the first container is concerned, it is usually not necessary to invert this container and, again, compared to comparable container formats, such as for example the box in a bag-in-box container, the outer container of a container structure Double wall integral has the primary function of structural strength, therefore, preferably a first recess of the vessel cavity can incorporate complex small radius cavity wall features as a way to maximize the stiffness of the thin walls in a Integral double-walled stretch blow molded container.

The primary purpose of an air gap between integrally connected and adjacent containers is to provide thermal insulation, both to keep the contents of the container hot, such as for coffee glasses, and to keep the contents of the container cold, such as for glasses and containers. of fast food. However, hot and cold drinks are typically consumed relatively quickly, so a completely closed and sealed air gap is usually not necessary for the air gap to function effectively as a thermal insulation layer.

The expression "completely closed" as taught in the prior art presupposes that an integral double-walled container must have two completely closed bottom walls; However, when a container is not being held in a user's hand, it is typically located on a substantially flat surface or kept in a transit box or tray and, as such, there is typically an at least substantially flat and completely flat surface. separated below and directly adjacent to the base of an integral double-walled container, thereby effectively acting as a completely closed bottom wall of a first container. Therefore, there are usually few drawbacks to a first container having only a partially closed bottom wall.

While the simplest form of an integral double-walled container formed as a result of the method and apparatus taught herein results in an open air gap, there are reasons to have an at least partially closed air gap, particularly adjacent to the partially closed bottom wall of a first container, with reasons including the overall integral structural integrity of the double-walled container and improved thermal insulation. As already characterized, an integral double-walled container is similar to a bag-in-box container format where the second smaller inverted container serves as the bag and the first container serves as the box. As a second smaller inverted container is typically thin-walled and with little or no additional wall rigidity features, once the liquid/solid contents are placed inside the "bag" of the second smaller inverted container, there is a risk that moves freely and adversely with respect to the "box" of the first container. While this movement may not cause structural failure of any kind, such relative movement could, at the very least, be unsettling to the user.

Incorporating in a set of dual container-shaped mold cavities at least one or more complex small radius cavity wall features in the form of abrupt/small radius changes extending inward into the first recessed walls of the container cavity, any movement in a second smaller inverted container relative to its first container can be minimized and therefore the overall structural integrity can be increased. The at least one or more complex small radius cavity wall features present in the form of abrupt/small radius changes extending inward in the first recess walls of the container cavity may result in a first container makes at least partial or engageable contact with its adjacent inverted second smaller container in any one or more places.

Such at least one or more complex small-radius cavity wall features in the form of abrupt/small-radius curvature changes extending inward into the first walls of the container cavity recess may also serve to provide a restraint. of the air gap in a double-wall finished integral container to provide at least partially or fully closed air gap sealing.

During the inversion process, it is not necessarily necessary to invert at least some portions of the bottom wall of a second smaller container, therefore, a cavity recess for a second smaller container bottom wall may also include at least one or more complex small radius cavity wall features in the form of abrupt/small radius cavity recess changes that may serve as an additional means of reducing movement between adjacent integral vessels in a dual integral vessel structure wall and/or as an additional way to provide air gap restriction.

To form such advantageous wall features in an integral stretch blow molded double wall container, a set of dual container mold cavities may include, but are not limited to:

• One or more abrupt/small radius changes in cavity wall shape and/or radial and/or longitudinal shape or any intermediate angular orientation,

• One or more abrupt/small radius changes in cavity wall shape and/or shape extending any distance inward and/or outward from the middle surface of any cavity wall,

• Abrupt/small radius changes in shape and/or shape that are continuous and/or discontinuous in any direction,

• If extended inwardly from the first cavity wall of the container, it may extend a distance by design so that the first stretch blow molded container and its second inverted container, when in their final integral structural form of double container wall that extends in the same direction as each other, may come into contact in a tactile manner, come into contact in an engaging manner or not make contact in any one or more places, or

• Any combination thereof.

Examples of complex small radius mold cavity wall features include, but are not limited to:

• Any form of logo, graphic design, signage, promotional information or similar as part of a cavity wall,

• Any geometric or non-geometric shape or form as part of a cavity wall,

• Any abrupt change in the height of the cavity wall, typified by the formation of a ridge,

• Any abrupt change in the height of the cavity wall that returns equally abruptly to substantially the height of the original cavity wall in the same plane typified by a cavity rib or channel,

• A raised or recessed thread form of any type as part of a cavity wall,

• Any combination thereof, or

• A complex geometric feature of the cavity wall in the form of an abrupt/small radius change readily apparent to those versed in the art.

During the stretch blow molding phase, heat-conditioned tubular blanks with a single open end are expanded outward by mechanical and/or gas pressure so that they stretch into the shape of a set of mold cavities. dual container shaped mold. For such integral double-walled containers, a first set of dual-container-shaped mold cavities typically includes integral, interconnected cavity recesses including, but not limited to:

• A large opening recess for mechanical and/or sealing engagement connection with the open end of the tubular blank,

• A first engageably connected container cavity recess that includes a mouth opening region, side wall regions, and a partially closed bottom wall region that may include small radius cavity wall features. for any purpose.

• A second, attachably connected, smaller container cavity recess that includes a mouth opening region, side wall regions, and a fully enclosed bottom wall region that may include small radius cavity wall features for any purpose. .

• With the first and second smaller vessel cavity recesses extending in opposite directions from each other.

Alternatively, during the stretch blow molding phase, the heat-conditioned tubular blanks with a first and a second open end are expanded outward by mechanical and/or gas pressure so that they conform by stretching to the shape of a set of dual container shaped mold cavities. For such integral double-walled containers, a first set of dual-container-shaped mold cavities typically includes integral, interconnected cavity recesses including, but not limited to:

• A large opening recess for a mechanical and/or sealing engagement connection to the first open end of a tubular blank,

• A first engageably connected container cavity recess that includes a mouth opening region, side wall regions, and a partially closed bottom wall region that may include small radius cavity wall features. for any purpose.

• A second, attachably connected, smaller container cavity recess that includes a mouth opening region, side wall regions, and a partially closed bottom wall region that may include small radius cavity wall features for any purpose. .

• With the first and second smaller vessel cavity recesses extending in opposite directions from each other,

• And a large opening recess engageably connected for a mechanical and/or sealing engagement connection to the second open end of a tubular blank.

During the second smaller container inversion phase, the second smaller heated containers are at least partially inverted upside down. A second set of dual vessel-shaped mold cavities typically includes integral, interconnected cavity recesses including, but not limited to: • A large opening recess for a mechanical latching and/or sealing connection to the partially closed wall below. from a first container,

• A first engageably connected container cavity recess that includes a mouth opening region, side wall regions, and a partially closed bottom wall region that may include small radius cavity wall features. for any purpose.

• A second, attachably connected, smaller container cavity recess that includes a mouth opening region, side wall regions, and a partially closed bottom wall region that may include small radius cavity wall features for any purpose. .

• With the first and second smaller vessel cavity recesses extending in opposite directions from each other,

• And at least one hookably attached profiled reversing piston recess, which forms part of the second smaller area of the bottom wall of the container,

• And may also include,

• At least a first container and/or a second smaller container thermal conditioning device, and

• At least one route for interconnection with at least one source of air pressure below atmospheric pressure.

A second smaller container cavity recess may be slightly smaller than its respective first container cavity recess, or a second smaller container cavity recess may be substantially smaller than its first container cavity recess. respective container. A second smaller container cavity recess may have substantially the same shape/shape as its respective first container cavity recess, or a second smaller container cavity recess may have a substantially different or completely different shape/shape. different from its first recess of the cavity of the respective container. A set of container-shaped mold cavities can be exact mirror image copies of each other, or a set of container-shaped mold cavities can have different cavity shapes from each other.

For high-speed production, it is usually preferable to have a greater number of fast steps in a production sequence rather than a smaller number of slow steps, since for any production sequence, the overall production throughput is normally determined by the slowest pace. Therefore, the method and apparatus for the production of integral double-walled containers is preferred to include a first and a second set of dual-container-shaped mold cavities to achieve the fastest production sequence cycle time. possible and therefore the lowest production part cost, however, as will be evident to those skilled in the art, a single set of dual container shaped mold cavities that combines all the features and functions of the two sets of dual-vessel-shaped mold cavities. Alternatively, more than two sets of dual-vessel-shaped mold cavities may be employed in a production sequence.

To ensure optimal inversion of a second, smaller vessel, it is important to control the stability of the wall in the region where the inverting and non-inverting wall sections are hookably connected:

• When it is desired to completely invert a second smaller container in a full mirror image position, the region for controlling wall stability in a set of dual container mold cavities is the connection region between the opening zones of the mouth of the first container and the second recesses of the cavity of the smaller container,

• When only partial reversal of a second smaller container to a substantially mirror position is desired, the region for controlling wall stability in a set of dual container mold cavities is considered necessary by design with respect to the final integral shape of the double-walled container to be formed.

Wherever the wall stability control region is located within a set of dual-vessel-shaped mold cavities, it is important to keep the relevant stretch blow molded wall region(s) as physically stable as possible to that a second smaller container can be inverted in an orderly manner, with the inversion process being:

It begins by pushing in reverse with at least one profiled inversion piston the bottom wall of a second smaller container so that the bottom wall remains at least substantially non-inverted and first moves in a direction of the longitudinal axis towards the opening of mouth,

Followed by an orderly inversion of the side walls, progressively starting from the bottom wall end of the side walls towards the mouth opening end of the side walls, and finally ending with the inversion of the mouth opening or wherever the design intends to conclude the investment.

A profiled reversing piston can have any shape/shape necessary to assist in the reversing range from a flat thrust face to a fully profiled shape that conforms to the final shape of the inner inverted bottom wall thereby ensuring that a second smaller container bottom wall is not at least substantially inverted. The preferred profile is a fully profiled shape that conforms to the final shape of the inverted interior bottom wall.

Wall stability control devices within a dual vessel mold cavity assembly include, but are not limited to:

• Applying greater than atmospheric interior air pressure to a set of dual vessel mold cavities to provide greater than atmospheric interior air pressure to an integral stretch blow molded dual vessel during inversion,

• Applying sub-atmospheric air pressure across a configured dual container mold cavity assembly to any one or more integral stretch blow molded dual container wall exterior surfaces in the region or regions required for control. of the stability of the wall,

• Utilize at least one of the openings in a set of dual container mold cavities for the insertion of at least one flexible wall surface support structure into the interior of a set of dual container mold cavities to provide mechanical stability of the wall against the relevant interior surfaces of the wall of the dual integral stretch blow molded container and/or may have at least one head shape shaped/formed in this manner to assist with the formation of the final inversion figure/shape desired at the intersection point of the inverting and non-inverting walls,

• Any combination thereof, or

• Any other wall stability control of the dual vessel mold cavity assembly apparent to those versed in the art.

Air pressure greater than atmospheric pressure is currently used to control wall stability during wall inversion with stretch blow molded bottles, such as for the creation of integral handle regions. However, normally the volumetric size of the wall inversion relative to the total volume of the blow-formed bottle is small and therefore any internal air pressure differential arising as a result of the wall inversion is easily controllable.

However, for double wall integral container structures, the difference in internal volume between the first stretch blow molded container and the second smaller integral container extends in opposite directions and the final double wall integral container where the first container and the second smaller inner inverted container extend in the same direction is substantial - and typically has a volumetric differential of more than 10 times. Since for high-speed production the requirement is that reversal occurs as quickly as possible, the build-up of internal air pressure between these two very different internal volumes can be difficult to control at best.

Where the rate of change of internal air pressure can be controlled directly during inversion, this may be by means of fast acting pneumatic control devices such as pressure regulators and/or relief valves. However, when the rate of change in internal air pressure exceeds the ability of rapid-acting pneumatic devices to reliably control, one stage of the reversing apparatus may incorporate one or more separate pressure chambers that are interconnected in a reliable manner. engageable with the interior of the first stretch blow molded container and the second integral smaller container such that their combined internal volume is substantially greater than the internal volume itself of the first stretch blow molded container and the second integral smaller container. Thus, when the second smaller container is inverted, the substantial internal volume change of the double-walled integral stretch blow molded container due to the inversion results in only a small overall volume change in the combined internal volume, and therefore internal air pressure changes during inversion can be minimized and therefore easily controlled. Any combination of pneumatic control devices and/or one or more pressure chambers can be used.

At least one of the openings in a set of dual container mold cavities can be used to insert at least one flexible surface support structure into the interior of a set of dual container mold cavities in order to provide stability of the inner wall surface for the integral double-walled container stretch blow molded during inversion. The one or more flexible surface support structures may be spring-loaded by any method to resiliently and engageably contact the relevant interior wall surfaces of a dual integral stretch blow molded container in regions where stability is required. of the wall surface. The one or more flexible surface support structures can be flexibly inserted and/or removed at any point before, during or after the inversion.

The at least one flexible surface support structure interior to a set of dual container mold cavities may include an interior shaping of the former to ensure that the transition region between the inverting and non-inverting walls is formed according to the design requirements.

While one or more flexible surface support structures remain in elastic and engageable contact with the interior wall surfaces of an integral double-walled container now inverted and by any method, a second smaller container now inverted remains in a conditioned state Thermally, a profiled reversing piston can extend further in the reversing direction, thereby causing at least part of the bottom wall and/or side walls of a second smaller container now partially or fully inverted to be extensiblely elongated. . In this way the internal volume of a second smaller container, now partially or completely inverted, can be increased, while at the same time the thickness of its side walls is reduced. Therefore, for any given target container volumetric capacity, the final total empty weight of the integral double-walled container can be further reduced and thus the unit production cost similarly reduced. Wall stretching of the second smaller container may occur after wall inversion and/or during wall inversion. The same profiled reversing piston can be used to stretch the wall, or a separate profiled piston can be used to stretch the sidewall.

In the event that it is necessary to add a process step to convert at least a partially closed bottom wall to a fully closed bottom wall, this may be by:

Press fit additional bottom walls of any suitable material,

Gluing or welding additional bottom walls of any suitable material,

Overmolding of additional bottom walls of substantially the same material or any material with suitable molecular bonding properties.

Formation of additional bottom walls by thermal deformation of parts of the original tubular blank,

Any combination thereof, or

Add additional bottom walls as evident to those versed in the technique.

Should it be necessary to add an additional process step to at least partially or completely enclose an air gap, this may be by:

The additional investment of any existing wall features,

Any form of welding process,

Any form of gluing process,

The addition of any type of sealing compound,

Bonding adhesive labels,

Any combination thereof, or

Any form of additional sealing method is readily apparent to those versed in the art.

Should it be necessary to add an additional process step to improve the thermal insulation properties of the air gap, this may be by adding any one or more insulating compounds to the air gap at any point in the sequence. production, including but not limited to;

gaseous compounds,

liquid compounds,

solid compounds, or

Any combination thereof.

During production, a tubular blank may be formed entirely and completely in an integral double-walled container, or one or more subsequent processes may be used to cut unwanted/unused portions of a tubular blank and/or cut any wall portion formed by blowing for any reason to form a finished integral double-walled container. As for example, the mechanical clamping and/or sealing area of a tubular blank may be at least substantially cut at some point in a production sequence.

An additional process step may be added to add by any device or method one or more additional features, elements, walls or subcomponents to an integral double-walled container. Just as an example, an integral double-walled vessel may have a process step that adjunctively adds at any point in a production sequence things like:

cup bases,

Handles for glasses,

Integral lid parts,

glass stems,

Promotional items of any kind,

Any combination thereof, or

Any additional features, elements, walls or subcomponents apparent to those skilled in the art.

In the event that after inversion, a second inverted smaller container is not completely inverted into the desired shape/shape, one or more additional process steps may employ the use of one or more separate devices to improve the shape/shape. final inverted, including but not limited to:

One or more trainers of any type,

The application of internal and/or external air pressure,

Any combination thereof, or

Any method or device of figure/shaping correction evident to those versed in the art.

The process steps to form an integral double-walled container may occur as in-line process steps, as adjacent process steps, or as remote process steps, or any combination thereof. It is preferred that the process steps occur in line and/or adjacent to each other. Each process step and apparatus device may occur only once in a production sequence in any order, or one or more process steps and/or apparatus device may occur multiple times, either sequentially or non-sequentially, depending on necessary to achieve the most efficient overall production performance. One or more steps of the process as taught in this document may be combined with each other or separated into substeps as necessary.

Major market applications for integral double-walled containers formed as a result of the method and apparatus taught herein include, but are not limited to:

As a cup and/or lid for fast food and coffee retail establishments,

As a bottle or jar for perishable foods,

As a bottle or jar for pharmaceutical, chemical and cosmetic products,

As a container for quick meals,

As a secondary packaging cup, bottle or container for any market sector.

In a first preferred embodiment, a method and apparatus is provided for the production of double-walled containers having the structure of two adjacent and integrally connected containers extending in the same direction with an air gap between them, stretch blow molded. as individual bodies made of thermoplastic material and suitable for mass production. Initially, a thermoplastic tubular blank is formed with an open end, where its RSmax is substantially 3 or less to minimize the wall thickness of both the tubular blank and the integral double-walled container to be molded. blown and stretched. The tubular blank is allowed to cool enough so that it falls below its melting temperature and therefore solidifies. The tubular blank is then thermally conditioned to a first thermal conditioning temperature within the thermal softening temperature range but below the melting temperature of the thermoplastic material. Once thermally conditioned, the tubular blank is mechanically stretched in the direction of the longitudinal axis with an LS substantially greater than 1, and blown outward by gas pressure so that RLmax is less than 3, and preferably of the order of 1 or less. The longitudinal mechanical stretching combined with the longitudinal and/or radial stretching by gas pressure conformably and stretchably adopts the tubular blank into the shape of a first set of dual container-shaped mold cavities to form as an intermediate product a dual integral stretch blow molded container having the structure of a first container and a second smaller container integrally connected, the first container and the second smaller container extending in opposite directions from each other. Additional thermal conditioning is then applied to thermally condition the second smaller stretch blow molded container and, if considered an advantage, at least part of the first container at a second thermally conditioned temperature. At least one profiled reversing piston and a second set of dual-vessel-shaped mold cavities are then provided along with one or more wall stability devices that apply to at least part of the wall surfaces of one or both of the two integrally connected stretch blow molded containers, such that the second side walls of the smaller container can be at least partially inverted from the inside out, while at the same time the bottom wall of the second smaller container at least substantially is not inverted, so that the second smaller container becomes a substantially mirror image inverted second smaller container extending in the same direction as and into the first container. Alternatively, a second smaller container can be inverted manually.

A first set of dual-vessel-shaped mold cavities typically includes integral, interconnected cavity recesses including, but not limited to:

A large opening recess for mechanical and/or sealing engagement connection to the open end of a tubular blank,

A first engageably connected container cavity recess that includes a mouth opening area, side wall areas, and a partially closed bottom wall area that may include small radius cavity wall features for any purpose.

A second, attachably connected, smaller container cavity recess that includes a mouth opening region, side wall regions, and a fully enclosed bottom wall region that may include small radius cavity wall features for any purpose.

With the first and second smaller container cavity recesses extending in opposite directions from each other.

A second set of dual-vessel-shaped mold cavities typically includes integral, interconnected cavity recesses including, but not limited to:

A large opening recess for a mechanical and/or sealing latching connection to the partially closed bottom wall of a first stretch blow molded container,

A first engageably connected container cavity recess that includes a mouth opening area, side wall areas, and a partially closed bottom wall area that may include small radius cavity wall features for any purpose.

A second, attachably connected, smaller container cavity recess that includes a mouth opening region, side wall regions, and a partially closed bottom wall region that may include small radius cavity wall features for any purpose.

With the first and second smaller vessel cavity recesses extending in opposite directions from each other,

and at least one clipably attached profiled reversing piston recess, which forms part of the second smaller area of the bottom wall of the container,

And may also include,

At least a first container and/or a second smaller container thermal conditioning device, and

At least one path for interconnection with at least one source of air pressure below atmospheric pressure.

Because the combination of the mechanical stretching phase before the blowing phase has an LS substantially greater than 1, the tubular blank has an RSmax substantially 3 or less, and the second inversion of the smaller container is assisted by the wall stability devices and profiled reversing pistons, an integral double-walled vessel having the structure of two adjacent and integrally connected vessels extending in the same direction with an air gap between them may be formed as a single body suitable for mass production. The air gap thus formed may be a partially sealed or open air gap.

Additional production steps can be added at any point in the sequence, including but not limited to:

• The use of wall stability devices and profiled inversion pistons to extensibly extend the length of the side wall of the second smaller inverted container,

• Cutting any part or parts of the integrally connected container and/or tubular blank by any method and for any reason,

• Convert any partially closed bottom wall to a completely closed bottom wall by any method and may result in the formation of a completely closed air gap.

• Further inversion of any feature or wall section in any integrally connected vessel by any method and for any reason may result in the formation of a partially or fully closed air gap.

• Adding an additional part or parts of any shape to any of the integrally connected containers by any method and for any reason may result in the formation of a partially or completely closed air gap.

• Adding additional material or materials of any form, property or nature to the air gap by any method and for any reason, including improving thermal insulation.

• The application of additional forming methods to ensure that the second smaller inverted container fully assumes its final design shape/shape.

• Print on any surface of any of the integrally connected containers by any method.

In a second preferred embodiment, a method and apparatus is provided for the production of dual containers having the structure of two adjacent and integrally connected containers extending in the same direction with an air gap between them, stretch blow molded as bodies. Individually made from thermoplastic material and suitable for mass production. Initially, a thermoplastic tubular blank is formed with a first and a second open end, where its RSmax is substantially 3 or less to minimize the wall thickness of both the tubular blank and the integral double-walled container being formed. It is going to be blow molded and stretched. The tubular blank is allowed to cool enough so that it falls below its melting temperature and therefore solidifies. The tubular blank is then thermally conditioned to a first thermal conditioning temperature within the thermal softening temperature range but below the melting temperature of the thermoplastic material. Once thermally conditioned, the tubular blank is mechanically stretched in the direction of the longitudinal axis with an LS substantially greater than 1, and blown outward by gas pressure so that RLmax is less than 3, and preferably of the order of 1 or less. The longitudinal mechanical stretching combined with the longitudinal and/or radial stretching by gas pressure conformably and stretchably adopts the tubular blank into the shape of a first set of dual container-shaped mold cavities to form as an intermediate product a dual integral stretch blow molded container having the structure of a first container and a second smaller container integrally connected, the first container and the second smaller container extending in opposite directions from each other. Additional thermal conditioning is then applied to thermally condition the second smaller stretch blow molded container and, if considered an advantage, at least part of the first container at a second thermally conditioned temperature. At least one profiled reversing piston and a second set of dual-vessel-shaped mold cavities are then provided along with one or more wall stability devices that apply to at least part of the wall surfaces of one or both of the two integrally connected stretch blow molded containers, such that the second side walls of the smaller container can be at least partially inverted from the inside out, while at the same time the bottom wall of the second smaller container at least substantially is not inverted, so that the second smaller container becomes a substantially mirror image inverted second smaller container extending in the same direction as and into the first container. Alternatively, a second smaller container can be inverted manually.

A first set of dual-vessel-shaped mold cavities typically includes integral, interconnected cavity recesses including, but not limited to:

• A large opening recess for a mechanical and/or sealing engagement connection to the first open end of a tubular blank,

• A first engageably connected container cavity recess that includes a mouth opening region, side wall regions, and a partially closed bottom wall region that may include small radius cavity wall features for any purpose.

• A second, attachably connected, smaller container cavity recess that includes a mouth opening region, side wall regions, and a partially closed bottom wall region that may include small radius cavity wall features for any purpose. .

• With the first and second smaller vessel cavity recesses extending in opposite directions from each other,

• And a large opening recess engageably connected for a mechanical and/or sealing engagement connection to the second open end of a tubular blank.

A second set of dual-vessel-shaped mold cavities typically includes integral, interconnected cavity recesses including, but not limited to:

• A large opening recess for a mechanical and/or sealing latching connection to the partially closed bottom wall of a first stretch blow molded container,

• A first engageably connected container cavity recess that includes a mouth opening region, side wall regions, and a partially closed bottom wall region that may include small radius cavity wall features for any purpose.

• A second, attachably connected, smaller container cavity recess that includes a mouth opening region, side wall regions, and a partially closed bottom wall region that may include small radius cavity wall features for any purpose. .

• With the first and second smaller vessel cavity recesses extending in opposite directions from each other,

• And at least one hookably attached profiled reversing piston recess, which forms part of the second smaller area of the bottom wall of the container,

• And may also include,

• At least a first container and/or a second smaller container thermal conditioning device, and

• At least one route for interconnection with at least one source of air pressure below atmospheric pressure.

Because the combination of the mechanical stretching phase before the blowing phase has an LS substantially greater than 1, the tubular blank has an RSmax substantially 3 or less, and the second inversion of the smaller container is assisted by the wall stability devices and profiled reversing pistons, an integral double-walled vessel having the structure of two adjacent and integrally connected vessels extending in the same direction with an air gap between them can be formed as a single body suitable for mass production. The air gap thus formed may be a partially sealed or open air gap.

Additional production steps can be added at any point in the sequence, including, but not limited to: • The use of wall stability devices and profiled reversing pistons to extensibly extend the length of the side wall of the second smaller container. invested,

• Cutting any part or parts of the integrally connected container and/or tubular blank by any method and for any reason,

• Convert any partially closed bottom wall to a completely closed bottom wall by any method and may result in the formation of a completely closed air gap.

• Further inversion of any feature or wall section in any integrally connected vessel by any method and for any reason may result in the formation of a partially or fully closed air gap.

• Adding an additional part or parts of any shape to any of the integrally connected containers by any method and for any reason may result in the formation of a partially or completely closed air gap.

• Adding additional material or materials of any form, property or nature to the air gap by any method and for any reason, including improving thermal insulation.

• The application of additional forming methods to ensure that the second smaller inverted container fully assumes its final design shape/shape.

• Print on any surface of any of the integrally connected containers by any method.

Where reference has been made to methods and/or apparatus as part of the formation of a double-walled container with the structure of two adjacent and integrally connected containers extending in the same direction with an air gap between them and formed as a single body from a tubular blank with a single open end, may equally be part of the methods and/or apparatus in the formation of a double-walled container with the structure of two adjacent and integrally connected containers extending in the same direction with an air gap between them and formed as a single body from a tubular blank with a first and a second open end, and vice versa.

Where reference has been made to a method and apparatus that at least substantially inverts the second smallest container and does not invert the first container, likewise a method and apparatus may at least substantially invert the first container and may not invert the second smallest container.

Where reference has been made to a method and apparatus where the second container is smaller than the first container, a method and apparatus may also have a first container that is smaller than the second container.

Other aspects of the invention, which should be considered in all their novel aspects, will become apparent from the following description, which is given by way of example only.

Brief description of the drawings

Examples of the invention will be apparent from the following description which is given by way of example with reference to the accompanying drawings which:

Figure 1 shows a three-dimensional cross-sectional view of a tubular thermoplastic resin initial blank according to a first preferred embodiment of the present invention;

Figure 2 shows a three-dimensional view of at least part of a first set of dual container-shaped mold cavities according to the same first preferred embodiment of the present invention;

Figure 3 shows a three-dimensional view of at least part of a second set of dual container-shaped mold cavities in accordance with any preferred embodiment of the present invention;

Figure 4 shows a three-dimensional cross-sectional view of a profiled reversing piston in accordance with any preferred embodiment of the present invention;

Figure 5 shows three-dimensional views of alternative internal volume configurations as part of an interior wall stability control at greater than atmospheric air pressure in accordance with any preferred embodiment of the present invention;

Figure 6 shows a three-dimensional view of an interior flexible surface support structure in accordance with any preferred embodiment of the present invention;

Figure 7 shows a three-dimensional cross-sectional view of a third stretch blow molding step in a production sequence of an integral double-walled container according to a first preferred embodiment of the present invention;

Figure 8 shows a three-dimensional cross-sectional view of an inversion workstation with stability control devices for integral stretch blow molded first and second smaller containers extending in opposite directions in accordance with any preferred embodiment of the invention. present invention;

Figure 9 shows a three-dimensional cross-sectional view of a first phase of a fourth inversion step in a production sequence of an integral double-walled container according to any preferred embodiment of the present invention;

Figure 10 shows a three-dimensional cross-sectional view of a second phase of the fourth reversal step of Figure 9 in accordance with any preferred embodiment of the present invention;

Figure 11 shows a three-dimensional cross-sectional view of a third reversal phase of the fourth reversal step of Figures 9 and 10 in accordance with any preferred embodiment of the present invention;

Figure 12 shows a three-dimensional cross-sectional view of a final phase of the fourth reversal step of Figures 9 to 11 in accordance with any preferred embodiment of the present invention;

Figure 13 shows a three-dimensional cross-sectional view of a tubular thermoplastic resin initial blank according to a second preferred embodiment of the present invention;

Figure 14 shows a three-dimensional view of at least part of a first dual container-shaped mold cavity arrangement according to the same second preferred embodiment of the present invention; and Figure 15 shows three-dimensional cross-sectional views of alternative configurations of dual container-shaped mold cavities in accordance with any preferred embodiment of the present invention.

Detailed description

It will be appreciated that expressions such as "upward", "downward", etc., as used in this specification, refer to the orientations shown in the drawings and to orientations obvious to those skilled in the art. Expressions are used to indicate relative orientations, but should not be considered limiting.

Referring to Figure 1, a closed thermoplastic resin tubular blank is depicted in a three-dimensional cross-sectional view in accordance with a first preferred embodiment of the present invention.

According to the first preferred embodiment of the present invention, a closed tubular blank 1 may have only one open end 2, and may be optimized by design so that its RSmax is substantially 3 or less to minimize the wall thickness 3 of the closed tubular blank 1 so as to minimize the wall thickness of the integral dual container to be stretched blow molded (not shown).

As the heat-conditioned tubular blanks are stretched by mechanical and/or gas pressure to stretch form them into sets of dual container-shaped mold cavities, one or more locations must be the tubular blanks;

• Mechanically fastened enough to allow stretching, and

• Securely fastened enough so that pressure can be exerted inside.

It is typical for the open end 2 of a closed tubular blank 1 to be substantially round (as shown), as this provides the most secure and efficient way of mechanical joining and sealing. However, apart from the open end 2, the circumferential shape 4 may be any combination of geometric and/or non-geometric shapes, or any change or changes in the circumference, as provided by the design and with respect to the rough tubular expansion. according to the final shape of the double-walled container to be formed.

For a closed tubular blank 1, a mechanical clamping can be performed on an open end 2. The mechanical fastening may be in the form of one or more integral mechanical fastening features 5 at an open end 2 that are engageably interconnected with external mechanical vise or clamp-type arrangements in a container-shaped mold cavity arrangement. dual (not represented). Such flange-shaped mechanical fastening features 5 may subsequently form the partially closed bottom wall of a first stretch blow molded container (not shown).

For a closed tubular blank 1, the sealing fastener can also be made at an open end 2 so that the gas pressure has at least one path 6 substantially sealed into it and interconnects in a latchable manner with style arrangements external sealing in a dual container shaped mold cavity arrangement (not shown). The sealing fastener is typically incorporated as part of the mechanical fastening features 5 in an open end 2, and may include any combination of common and/or additional integral features to assist with sealing.

The preferred thermoplastic resin for a closed tubular blank 1 is polypropylene (PP); however, any suitable thermoplastic resin can equally be used. A thermoplastic resin may be oil-based or bio-based, clear/transparent, semi-transparent or opaque, its natural resin color or any color or combination of colors, a single type of resin or a combination of resin types, or any combination thereof.

Referring to Figure 2, at least part of a first set of dual container-shaped mold cavities is represented in a three-dimensional view according to the same first preferred embodiment of the present invention.

In accordance with the first preferred embodiment of the present invention, at least part of a first set 7 of dual container-shaped mold cavities typically includes integral and interconnected cavity recesses including, but not limited to:

• A large opening recess for mechanical engagement and/or sealing connection 8 with the open end 2 of a tubular blank 1 (not shown),

• A first latchably connected container cavity recess 9 that includes a mouth opening region 10, side wall regions 11, and a partially closed bottom wall region 12 that may include radius cavity wall features. small for any purpose, and where at least one partially closed bottom wall can be the mechanical latching and/or sealing connection features 8 at the end of the side walls 11,

• A second, smaller, attachably connected container cavity recess 13, which includes a mouth opening region 14, side wall regions 15, and a fully closed bottom wall region 16 that may include cavity wall features. small radius for any purpose,

• With the first 9 and the second smaller container 13, the recesses of the cavities extend in opposite directions from each other and are connected 17 integrally.

Examples of complex small radius mold cavity wall features include, but are not limited to:

• Any form of logo, graphic design, signage, promotional information or the like 18 as part of a cavity wall,

• Any geometric or non-geometric shape or form as part of a cavity wall (not shown), • Any abrupt change in the height 19 of the cavity wall, typified by the formation of a ridge, • Any abrupt change in height of the cavity wall returning equally abruptly substantially to the height of the original cavity wall in the same plane typified by a cavity rib or a cavity channel,

• A raised or recessed thread form of any type as part of a cavity wall (not shown), • Any combination thereof, or

• A complex geometric feature of the cavity wall in the form of an abrupt/small radius change readily apparent to those versed in the art.

Referring to Figure 3, at least part of a second set of dual container-shaped mold cavities is depicted in a three-dimensional view in accordance with any preferred embodiment of the present invention.

In accordance with any preferred embodiment of the present invention, at least part of a second set 21 of dual container-shaped mold cavities typically includes integral and interconnected cavity recesses including, but not limited to:

• A large opening recess for mechanical engagement and/or sealing connection 22 with the partially closed bottom wall of a first stretch blow molded container (not shown),

• A first, snap-connected stretch blow molded container cavity recess 23, which includes a mouth opening region 24, side wall regions 25, and a partially closed bottom wall region 26 that may include features of small radius cavity wall for any purpose, and where at least one partially closed bottom wall may be the mechanical latching and/or sealing connection features 22 at the end of the side walls 25,

• A second, smaller, snap-connected stretch blow molded container cavity recess 27 including a mouth opening region 28, side wall regions 29, and at least part of a bottom wall region 30 partially or fully enclosed which may include small radius cavity wall features for any purpose,

• With the cavity recesses of the first stretch blow molded container 23 and the second smaller stretch blow molded container 27 extending in opposite directions from each other and being integrally connected 31,

• And at least one profiled reversing piston recess 32 engageably connected as part of the bottom wall 30 of the second smaller stretch blow molded container 27,

• And may also include,

• At least a first stretch blow molded container 23 and/or a second smaller stretch blow molded container 27, thermal conditioning device, as represented in the form of at least one separate heater insert 33 with a gap 34 of air between the heated and unheated areas so that zones of the cavity heater insert 33 can be heated by any known method, and/or parts of the cavity can remain unheated as desired, and

• At least one path 35 for interconnection with at least one source of air pressure below atmospheric pressure (not shown).

Referring to Figure 4, a profiled reversing piston is depicted in a three-dimensional cross-sectional view in accordance with any preferred embodiment of the present invention.

In accordance with any preferred embodiment of the present invention, a profiled reversing piston 36 may have any shape/shape necessary to assist reversing, ranging from a flat thrust face (not shown) to a fully profiled shape that conforms to the final shape 37 of the inverted inner bottom wall to thereby ensure that a second stretch blow molded bottom wall of the smaller container is at least substantially not inverted (not shown). The preferred profile is a fully profiled shape that conforms to the final shape 37 of the inner inverted bottom wall and sufficiently supports a second smaller stretch blow molded container bottom wall during the inversion process.

As shown, the profiled reversing piston 36 may have a recessed thread 38 as a possible way to attach a profiled reversing piston 36 to a wall reversing drive mechanism (not shown). There may be any number of reversing pistons 36 shaped into one or more different shapes/shapes in a production sequence. Preferably for overall simplicity and efficiency, there is only one profiled reversing piston 36.

Wall stability control devices within a dual vessel mold cavity assembly include, but are not limited to:

• Applying sub-atmospheric air pressure through a configured dual container mold cavity to one or more exterior surfaces of the stretch blow molded container walls in the region or regions required for control of the stability of the container. the wall, as represented in Figure 3 by means of at least one path 35 for interconnection with at least one source of air pressure below atmospheric,

• Applying a supra-atmospheric air pressure interior to a set of dual container mold cavities to provide a supra-atmospheric air pressure interior to stretch blow molded containers during inversion (not shown ),

• Utilize at least one of the openings of the mechanical and/or sealing engagement connection feature 22 in a second set of dual container mold cavities 21 for the insertion of at least one interior flexible wall surface support structure. to a second set of dual container mold cavities in order to provide mechanical wall stability against relevant stretch blow molded interior container wall surfaces and/or to provide at least one shaped/formed head shape thereof. manner to assist with the formation of the desired final inversion shape/shape at the point of intersection of the inverting and non-inverting walls (not shown),

• Any combination thereof, or

• Any other stability control of the wall of the dual vessel mold cavity assembly apparent to those versed in the art.

Referring to Figure 5, alternative internal volume configurations are depicted in a three-dimensional view as part of a stability control of the inner wall with air pressure greater than atmospheric pressure in accordance with any preferred embodiment of the present invention.

For integral double-wall container structures, the difference in internal volume between the first stretch-blow molded container and the second integral smaller container extending in opposite directions (the volume of air within the two stretch-molded containers stretch blow molded) and the final integral double-walled container where the first stretch blow molded container and the second smaller inverted inner container extend in the same direction 40 (the air gap between the two stretch blow molded containers ) is substantial - and is typically a volumetric differential of more than 10 times. Since for high-speed production the requirement is that reversal occurs as quickly as possible, the build-up of internal air pressure between these two very different internal volumes can be difficult to control at best.

Where the rate of change of internal air pressure can be controlled directly during inversion, this may be by means of fast acting pneumatic control devices such as pressure regulators and/or relief valves (not shown). However, when the rate of change in internal air pressure exceeds the ability of the fast-acting pneumatic devices to reliably control, one stage of the reversing apparatus may incorporate one or more separate pressure chambers 41 that are interconnected. engageably with the interiors of the first stretch blow molded container 39 and a second smaller container 40 integral so that their combined internal volumes 42 (=39+41) and 43 (=40+41) are substantially greater than the volumes individual internals of the first stretch blow molded container 39 and the second smaller integral container 40. In this way, as the second smaller stretch blow molded container is inverted from the combined internal volume 42 to the combined internal volume 43, the combined internal volume change due to the inversion is small and therefore the change in Internal air pressure can be easily minimized and controlled. Any combination of pneumatic control devices and/or one or more pressure chambers 41 can be used.

Referring to Figure 6, an inner flexible surface support structure is depicted in a three-dimensional view in accordance with any preferred embodiment of the present invention.

In accordance with any preferred embodiment of the present invention, at least one large opening recess for mechanical engagement and/or sealing connection 22 in a second set 21 of dual container-shaped mold cavities of Figure 3 can be used to insert at least one inner flexible surface support structure 44 into the interior of a second set 21 of dual container mold cavities to provide stability to the inner wall surface of any stretch blow molded container (not shown ) during the investment. The one or more inner flexible surface support structures 44 may be spring loaded by any method in order to elastically and latchfully contact relevant stretch blow molded inner wall surfaces of the container at any inner surface region. where stability of the wall surface is required.

As shown, an inner flexible surface support structure 44 may have at least one spring arm 45, and any spring arm 45 may have a shaped head 46, with the head shape being thus shaped/formed to assist with the formation of the desired final inversion figure/shape at the point of intersection of the inverting and non-inverting walls. Additional springs may be inserted at any position in an inner flexible surface support structure 44 (not shown), and may advantageously be inserted between each head 46 formed in the gap 47 between heads. The one or more inner flexible surface support structures 44 can be flexibly inserted and/or removed at any point in a production sequence, either before, during or after inversion.

A first step in a production sequence of an integral double-walled container may be the formation of a tubular blank 1 of Figure 1. After their production, the tubular blanks 1 are allowed to cool enough so that fall below their melting temperature and therefore solidify. The tubular blanks 1 may be formed integrally with or adjacent to one or more different sequence steps, or alternatively may be formed remotely from one or more sequence steps. The forming method may be by any suitable process known to those skilled in the art, but preferably is by injection molding or extrusion.

A second step in a production sequence of an integral double-walled container may be the thermal conditioning of the tubular blank 1 to a first thermal conditioning temperature. Thermal conditioning may be performed by any thermal conditioning method known to those skilled in the art, and may be an integral part of at least one other sequence step or a separate, individual sequence step. The thermal conditioning may be a temperature increase if, for example, the tubular blanks 1 are remotely formed to form an integral double-walled container and therefore need to be heated upwards to the thermal forming temperature, or the thermal conditioning may be a decrease in temperature if, for example, adjacent or integral tubular blanks 1 are formed at least one double-walled integral container forming sequence step and therefore need to be cooled down to the thermal formation temperature. Preferably, the average thermal conditioning temperature of the tubular blank 1 is of the order of 80 to 100 degrees Celsius.

Referring to Figure 7, a third stretch blow molding step in a production sequence of an integral double-walled container is depicted in a three-dimensional cross-sectional view according to the same first preferred embodiment of the present invention.

According to the first preferred embodiment of the present invention, a third step in a production sequence of an integral double-walled container may be the stretch blow molding 48 of a heat-conditioned tubular blank 1. As shown at 48a, the heat-conditioned tubular blank 1 is loaded into a first set 7 of dual container-shaped mold cavities. As depicted at 48b, a device 49 then mechanically stretches the heat-conditioned tubular blank 1, assisted by mechanical and/or sealing features 50 that may include the integral mechanical clamping features 5 of the tubular blank 1 of the figure. 1 and the mechanical engagement and/or sealing connection 8 of the first set 7 of dual container-shaped mold cavities of Figure 2. As shown at 48c, gas pressure (not shown) is then applied internally to the tubular blank 1 mechanically stretched through substantially sealed via 6, with the aid of mechanical and/or sealing features 50.

The combination of mechanical stretching and gas pressure stretching forms the heat-conditioned tubular initial blank 1 to the shape of the first set 7 of dual container-shaped mold cavities to thereby form an integral blow-molded dual container 51 and stretched with the structure of a first stretch blow molded container 52 and a second smaller container 53 integrally connected, with the first container 52 and the second smaller container 53 extending in opposite directions from each other

The mechanical stretching of the heat-conditioned tubular blank 1 in the direction of the longitudinal axis has an LS greater than 1, and when combined with the blow forming ratio RS at any point along the tubular blank, RLmax should not be substantially greater than 3 and preferably should be substantially 1 or less.

Gas pressure blow forming may begin after mechanical stretching is completed, or gas pressure blow forming may begin before mechanical stretching is completed. Thermal conditioning may occur separately from the first set 7 of dual container shaped mold cavities and/or may occur as an integral part of the first set 7 of dual container shaped mold cavities (not shown).

Thermal conditioning, whether an increase or decrease in temperature, may also be applied to any one or more parts or subparts of the apparatus, such as for example only:

• Applying cooling to one or more regions in a set 7 of mold cavities in order to help return a blow-formed integral dual container 51 to substantially room temperature once a tubular blank 1 has formed conformably and stretchable the shape of a first set 7 of dual container-shaped mold cavities,

• Applying cooling (not shown) to a mechanical stretching device 49 to counteract heat buildup of the mechanical stretching device 49 that can lead to rupture of a thin-walled tubular blank 1 during mechanical stretching phase 48b and /or the gas pressure blowing formation phase 48c.

Referring to Figure 8, an inversion workstation with stability control devices for a first and second integral smaller stretch blow molded containers extending in opposite directions is depicted in a three-dimensional cross-sectional view according to with any preferred embodiment of the present invention.

In accordance with any preferred embodiment of the present invention, an inversion workstation 54 may include one or more of the following:

• A second set 21 of dual container mold cavities (substantially half of the set shown),

• At least one method of heating the first stretch blow molded container and/or the second smaller container, represented as at least one separate heater insert 33,

• At least one path 35 for interconnection with at least one source of air pressure below atmospheric (not shown),

• At least one profiled reversing piston 36,

method of movement 55 of the at least one reversing piston 36 profiled with respect to the longitudinal axis of the second set 21 of dual container mold cavities,

• At least one inner flexible surface support structure 44, as shown in an elastically compressed state as a result of a spring tensioning plate 56 to allow the inner flexible surface support structure 44 to retract smoothly and freely out of the interior and/or pass into the second set of dual container mold cavities 21 through the large opening recess for mechanical engagement and/or sealing connection 22,

• Method of moving 57 of the spring tensioning plate 56 longitudinally with respect to at least one inner flexible surface support structure 44,

A structure for mounting and supporting movement 58 of at least one inner flexible surface support structure 44,

• Method of movement 59 of the assembly and support structure 58 of movement with respect to the longitudinal axis of the second set 21 of dual container mold cavities,

• At least one integral pressure chamber 60,

• And at least one pneumatic control device (not shown).

Referring to Figure 9, a first phase of a fourth reversal step in a production sequence of an integral double-walled container is depicted in a three-dimensional cross-sectional view in accordance with any preferred embodiment of the present invention.

In accordance with any preferred embodiment of the present invention, a reversal step begins with the placement of an integral dual stretch blow molded container 51 with the structure of a first container 52 and a second smaller container 53 integrally connected extending in directions opposite each other within the second set 21 of dual container mold cavities of an inversion work station 54. The dual integral stretch blow molded container 51 may be of any preferred embodiment in accordance with the present invention.

The at least one or more parts of a dual integral stretch blow molded container 51 that is to be inverted need to be thermally conditioned at a second thermally conditioned temperature. Thermal conditioning can be carried out by any method and can occur before placement within the reversing work station 54 and/or after placement within the reversing work station 54. As shown, the reversing work station 54 may include at least one heater insert 33.

The second thermal conditioning temperature may be the same or different from the first thermal conditioning temperature.

Following placement of an integral stretch blow molded dual container 51 within the inversion work station 54, the motion mounting and support structure 58 can be moved longitudinally toward the second set 21 of dual container mold cavities. , thereby moving the at least one inner flexible surface support structure 44 into the dual integral stretch blow molded container 51. The interior insertion of the at least one interior flexible surface support structure 44 may be assisted by the spring tensioning plate 56 that elastically compresses the at least one interior flexible surface support structure 44 so that it can move smoothly and freely toward the interior of the dual integral stretch blow molded container 51 through the large opening recess for the mechanical engagement and/or sealing connection 22.

Referring to Figure 10, a second phase of the fourth reversal step of Figure 9 is depicted in a three-dimensional cross-sectional view in accordance with any preferred embodiment of the present invention.

In accordance with any preferred embodiment of the present invention, once at least one inner flexible surface support structure 44 has been correctly positioned within the dual integral stretch blow molded container 51, the spring tensioning plate 56 can retract rearwardly with respect to the dual integral stretch blow molded container 51 such that the inner flexible surface support structure 44 can elastically flex outwardly 61 to connect/engageably contact one or more relevant interior surfaces of the container 51 dual integral stretch blow molded which may require inversion support.

At least one pressure source (not shown) may apply a higher than atmospheric pressure 62 to the interior of the dual integral stretch blow molded container 51 and pressure chamber 60.

At least one pressure source (not shown) may apply a sub-atmospheric pressure to the exterior of the dual integral stretch blow molded container 51 at any one or more relevant locations (not shown).

Referring to Figure 11, a third reversal phase of the fourth reversal step of Figures 9 and 10 is depicted in a three-dimensional cross-sectional view in accordance with any preferred embodiment of the present invention.

According to any preferred embodiment of the present invention, once one or more relevant areas of the dual integral stretch blow molded container 51 have been thermally conditioned to a second thermal conditioning temperature and any one or more methods of wall stability control, at least one profiled reversing piston 36 can move longitudinally 63 with respect to the dual integral stretch blow molded container 51 to begin reversing the second smaller stretch blow molded container 53.

To ensure optimal inversion of a second smaller stretch blow molded container 53, it is important to control the stability of the wall in the region where the inverting and non-inverting wall sections are engageably connected:

• When full inversion of a second smaller stretch blow molded container 53 in a full mirror image position is desired, the region for controlling wall stability in a set 21 of dual container mold cavities is the connection region between the mouth opening areas 64 of the first stretch blow molded container 52 and the second smaller container 53,

• When only partial inversion of a second smaller stretch blow molded container 53 in a substantially mirror image position is desired, the wall stability control region in a set 21 of dual container mold cavities It is considered necessary by design with respect to the final integral shape of the double-walled container being formed.

Wherever the wall stability control region is located within a set of dual container-shaped mold cavities 21, it is important to keep the relevant stretch blow molded wall regions as physically stable as possible to that a second smaller stretch blow molded container 53 is inverted in an orderly manner, the inversion process being:

• Begin pushing in reverse with at least one reversing piston 36 profiled in the bottom wall 65 of a second smaller container 53 such that the bottom wall 65 remains at least substantially non-inverted and moves first in a direction 63 longitudinal axis towards the mouth opening 64,

• Follow an orderly inversion of the side walls 66, starting progressively from the end of the bottom wall of the side walls in the direction towards the mouth opening end 64 of the side walls 67, and

• Finally finish with the inversion of the mouth opening 64 or in any other place where the inversion by design is intended to be completed.

The at least one inner flexible surface support structure 44 may have at least one head shape shaped/formed in this manner to assist with the formation of the desired final inversion shape/shape at the point of intersection of the inverter walls and non-inverting, as shown only in the example as the mouth opening areas 64.

One or more wall stability control methods may be operative at any given point within an inversion sequence, including, but not limited to:

• At least one inner flexible surface support structure 44 engaged or retracted at any point in the sequence so that, as necessary, it elastically flexes outwardly 61 to thereby effectively connect/engageably contact a any one or more relevant interior surfaces of the dual integral stretch blow molded container 51,

• Above atmospheric pressure 62 applied or released at any point in the sequence,

• Below atmospheric pressure (not shown) applied or released at any point in the sequence, or

• Any combination thereof.

Likewise, inversion can occur without any wall stability control method being applied, such as only when the inversion is performed manually.

Referring to Figure 12, a final phase of the fourth reversal step of Figures 9 to 11 is depicted in a three-dimensional cross-sectional view in accordance with any preferred embodiment of the present invention.

According to any preferred embodiment of the present invention, reversing has been completed when at least one profiled reversing piston 36 has reached its final design position in a longitudinal direction 63. In this point:

• The at least one inner flexible surface support structure 44 may be retracted 58 and the spring tensioning plate 56 may be moved so as to once again elastically compress the inner flexible surface support structure 44, or

• Prior to this retraction, the at least one inner flexible surface support structure 44 may remain engaged and the at least one profiled reversal piston 36 may continue to move further in a longitudinal direction 63 so that any inverted wall(s) may be elongated. in an extensible manner (not shown).

To finish the fourth investment step:

• At any point, any pressure 62 above atmospheric can be released,

• At any point, any source of sub-atmospheric pressure (not shown) can be disengaged, • The at least one profiled reversing piston 36 can be retracted to its initial position (not shown).

As a result of the combination of the mechanical stretching phase before the blowing phase having an LS substantially greater than 1, the tubular blank has an RSmax substantially 3 or less, at least one set of mold cavities shaped like dual container and the profiled pistons, an integral double-walled container 68 can be formed as a single body suitable for mass production, with the structure of a first container 69 and a second smaller container 71 integrally connected and at least substantially inverted , and whereby the first container 69 and the second smaller inverted container 71 extend in the same direction with respect to each other thereby forming an open or at least partially sealed air gap 72 between them.

Additional production steps may be added at any point in the sequence, including, but not limited to: • Cutting any part or parts of the integrally connected vessel and/or tubular blank by any method and for any reason,

• Convert any partially closed bottom wall to a completely closed bottom wall by any method, and may result in the formation of a completely closed air gap.

• Further inversion of any feature or wall section in any integrally connected vessel by any method and for any reason may result in the formation of a partially or fully closed air gap.

• Adding an additional part or parts in any way to any of the integrally connected containers by any method and for any reason may result in the formation of a partially or completely closed air gap.

• Adding additional material or materials of any form, property or nature to the air gap by any method and for any reason, including improving thermal insulation.

• The application of additional shaping/forming methods to ensure that the second smaller inverted container fully assumes its final design shape/figure.

• Print on any surface of any of the integrally connected containers by any method.

In situations where mass production speeds are not required, a second, smaller container can be manually inverted.

Referring to Figure 13, an open thermoplastic resin tubular blank is depicted in a three-dimensional cross-sectional view in accordance with a second preferred embodiment of the present invention.

According to the second preferred embodiment of the present invention, an open tubular blank 73 may have a first open end 74 and a second open end 75, and may be optimized by design so that its RSmax is substantially 3 or less to minimize the wall thickness 76 of the open tubular blank 73 as well as to minimize the wall thickness of the integral double-walled container to be stretched blow molded (not shown).

As the heat-conditioned tubular blanks are stretched by mechanical and/or gas pressure to stretch form them into sets of dual container-shaped mold cavities, one or more locations must be the tubular blanks;

• Mechanically fastened enough to allow stretching, and

• Securely fastened enough so that pressure can be exerted inside.

It is typical for the open ends 74 and 75 of an open tubular blank 73 to be substantially round (as shown), as this provides the most secure and efficient means of mechanical joining and sealing. However, other than the open ends 74 and 75, the circumferential shape 77 may be any combination of geometric and/or non-geometric shapes, or any change in circumference, as provided by the design and with respect to the expansion of the tubular blank according to the final shape of the double-walled container to be formed.

For an open tubular blank 73, mechanical clamping may be performed at both ends 74 and 75. The mechanical clamping may be in the form of one or more integral mechanical clamping features 78 at one or both open ends that interconnect in a manner engageable with an external mechanical vise or clamp type arrangements in a dual vessel shaped mold cavity arrangement (not shown). There may also be no clamping features 79 on one or both open ends.

For an open tubular initial blank 73, the sealing fastener may also be made at one or both open ends so that the gas pressure has at least one substantially sealed path 6 to its interior and which is engageably interconnected with arrangements. external sealing style in a dual container shaped mold cavity arrangement (not shown). Seal fastening is typically incorporated as part of the mechanical fastening and may include any combination of common and/or additional integral features to assist with sealing.

The preferred thermoplastic resin for an open tubular initial blank 73 is polypropylene (PP); however, any suitable thermoplastic resin can equally be used. A thermoplastic resin may be oil-based or bio-based, clear/transparent, semi-transparent or opaque, its natural resin color or any color or combination of colors, a single type of resin or a combination of resin types, or any combination thereof.

Referring to Figure 14, at least part of a first dual container-shaped mold cavity arrangement is depicted in a three-dimensional view in accordance with the same second preferred embodiment of the present invention.

According to the second preferred embodiment of the present invention, at least part of a first dual container-shaped mold cavity arrangement 80 typically includes, but is not limited to:

• At least part of a first set 81 of dual container-shaped mold cavities with integral and interconnected cavity recesses including, but not limited to:

• A large opening recess for mechanical engagement and/or sealing connection 82 that can be connected to at least one open end of an open tubular blank 73,

• A first latchably connected container cavity recess 83 that includes a mouth opening region 84, side wall regions 85, and a partially closed bottom wall region 86 that may include radius cavity wall features. small for any purpose,

• A second, attachably connected, smaller container cavity recess 87 that includes a mouth opening region 88, side wall regions 89, and a partially closed bottom wall region 90 that may include radius cavity wall features. small for any purpose,

• With the first 83 and the second cavity recesses of the smaller container 87 extending in opposite directions from each other and integrally connected 91, and

• An arrangement to assist with the mechanical stretching of an open tubular blank 73 having two open ends, as represented in the form of an arrangement 92 that can be sealed and/or mechanically engaged with at least one open end 93 of an open tubular blank 73 by any known method to assist with mechanical stretching of a heated open tubular blank in a direction 94 of the longitudinal axis.

The process steps to form an integral double-walled container may occur as in-line process steps, as adjacent process steps, or as remote process steps, or any combination thereof. It is preferred that the process steps occur in line and/or adjacent to each other.

Each process step and apparatus device as taught may occur only once in a production sequence in any order, or one or more process steps and/or apparatus device may occur multiple times, whether sequentially or not. sequentially as needed to achieve the most efficient overall production performance. One or more steps of the process as taught in this document may be combined with each other or separated into substeps as necessary.

Where reference has been made to methods and/or apparatus as part of the formation of a double-walled stretch blow molded container with the structure of two adjacent and integrally connected containers extending in the same direction as each other and with a gap of air between them and formed as a single body from a tubular blank with a single open end, may also be part of the methods and/or apparatus in the formation of a double-walled stretch blow molded container with the structure of two adjacent and integrally connected containers extending in the same direction as each other with an air gap between them and formed as a single body from a tubular blank with a first and a second open end, and vice versa.

Where reference has been made to a method and apparatus that at least substantially inverts the second smallest container and does not invert the first container, likewise a method and apparatus may at least substantially invert the first container and may not invert the second smallest container.

Where reference has been made to a method and apparatus where container inversion is as a result of mechanical devices, a method and apparatus may also include one or more manual container inversion steps.

Referring to Figure 15, alternative dual container-shaped mold cavity configurations are depicted in a three-dimensional view in accordance with any preferred embodiment of the present invention.

According to any preferred embodiment of the present invention, a second smaller container cavity recess may be slightly smaller than its respective first container cavity recess, or a second smaller container cavity recess may be substantially smaller than its first recess of the respective container cavity (not shown).

A second smaller container cavity recess may have substantially the same shape/shape 95 as its respective first container cavity recess, or a second smaller container cavity recess may have a substantially different shape/shape 96. or totally different from its first recess of the cavity of the respective container. The mold cavity set halves in a container-shaped mold cavity set may be exact mirror image copies of each other, or the mold cavity halves in a container-shaped mold cavity set may have different cavity shapes from each other (not shown).

Major market applications for integral double-walled containers formed as a result of the method and apparatus taught herein include, but are not limited to:

• As a cup for fast food and coffee retail establishments, as an example only as already represented in the dual container-shaped mold cavity configurations of the previous figures, • As a plate or lid for fast food and coffee retail establishments, as an example only as shown in the dual container shaped mold cavity configuration 97,

• As a bottle or container for perishable foods, pharmaceuticals, chemicals and cosmetics, as an example only as represented in the dual container shaped mold cavity configurations 98 and 99,

• As a fast food container, as an example only as shown in the dual container shaped mold cavity configuration 100,

• As a secondary packaging cup, tumbler, bottle, plate, lid or container for any market sector, as an example only as shown in dual container mold cavity configurations 97, 98, 99 and 100.

Where reference has been made to a method and apparatus where the second container is smaller than the first container, similarly a method and apparatus may have a first container that is smaller than the second container.

Claims (23)

1. A method of producing a double-walled container with the structure of two integrally connected (17, 31, 70, 91) and adjacent containers extending in the same direction (40) with an air gap (34) between them , the method that includes the steps of: providing a first mold (83, 9) with a first (83, 9) mold cavity having a dual container shape; providing a thermoplastic tubular blank (1) below the melting temperature with a first open end (83, 9) and a second opposite end, the blank having an initial blank length LO and a lower RSmax a 3, where RSmax is defined herein as the largest value of RS that occurs along the length of the tubular blank (1) and the radial stretch ratio RS is defined herein as the ratio between a circumference at any point after pressure stretching and the corresponding circumference of the original tubular blank (1); thermally conditioning the initial tubular blank (1) at a first (83, 9) thermally conditioned temperature within a thermally softened temperature range but below the melting temperature of the thermoplastic material; placing the heat-conditioned tubular blank (1) inside the first cavity (83, 9) of the dual container-shaped mold; apply a mechanical blank stretcher to mechanically stretch the heat-conditioned tubular blank (1) in a direction (63, 94) of the longitudinal axis to a stretched length L1, so that the longitudinal stretching ratio LS, defined herein document as the L1/LO ratio, is greater than 1; blow forming the longitudinally outwardly stretched tubular blank (1) by gas pressure to form the longitudinally stretched tubular blank (1) to the first (83, 9) mold cavity so that the maximum molding ratio stretch blow RLmax, defined herein as the ratio between RSmax and LS, is less than 3 and preferably substantially 1 or less; obtain as an intermediate product a dual integral stretch blow molded container with the structure of a first container (52, 69) and a second container integrally connected (17, 31, 70, 91), with the first container (52, 69) and the second container extending in directions (39) opposite to each other, wherein said second end of the tubular blank (1) forms a bottom portion of the second container; and then: inverting the second container so that it extends in the same direction (40) as the first container (52, 69); obtain as a final product an integral double-walled stretch blow molded container with the structure of a first container (52, 69) and a second integrally connected container (17, 31, 70, 91) extending in the same direction (40) with an air gap (34) between the first container (52, 69) and the second container; characterized because The step of inverting the second thermally conditioned container is performed by: providing at least one profiled reversing piston (36) capable of moving in the longitudinal direction (63) of the second dual container-shaped mold cavity; engaging the at least partial bottom wall (30, 65) of the second climate-controlled container with the at least one profiled reversing piston (36); displacing the at least one profiled reversing piston (36) in the longitudinal direction (63) of the second mold cavity in the form of a dual container such as to displace the at least partial bottom wall (30, 65) of the second air-conditioned container towards and into the first container (52, 69), wherein a side wall of the second climate container progressively inverts with the progression of displacement of the wall (30, 65) below the second climate container. 2. Method according to claim 1, further comprising, before the step of inverting the second container, the step of: - thermally conditioning the dual integral stretch blow molded container in any relevant region or regions of the first container and/or second container at a second thermal conditioning temperature; wherein the step of inverting the second container is executed while the dual integral stretch blow molded container is in a thermally conditioned state. 3. Method according to claims 1 and 2, further comprising the steps of: - providing a second mold with a second mold cavity having a dual container shape; - placing the integral stretch blow molded dual container within the second cavity of the dual container shaped mold; wherein the step of inverting the second container is executed while the integral stretch blow molded dual container is within the second cavity of the dual container shaped mold. 4. Method according to claims 1 to 3, wherein the thermal conditioning step of the integral stretch blow molded dual container is executed before insertion into the second cavity of the dual container shaped mold, while it is within the second mold cavity in the form of a dual container, or both. 5. Method according to claims 1 and 2, further comprising the step of manually inverting the second container. 6. Method according to any one of the preceding claims, wherein said second end of the tubular blank is closed. 7. Method according to any one of the preceding claims, wherein said second end of the tubular blank is open. 8. Method according to any one of the preceding claims, further comprising the step of stabilizing a side wall of the first container and/or second container during the step of inverting the second container. 9. Method according to claim 8, wherein the step of stabilizing a side wall of the first container and/or second container comprises the step of applying an interior air pressure greater than atmospheric to at least one integrally connected pressure chamber and/or the cavity of the dual container mold to provide a greater than atmospheric interior air pressure to the integral stretch blow molded dual container during inversion. 10. Method according to claim 8 or 9, wherein the step of stabilizing a side wall of the first container and/or second container comprises the step of applying a less than atmospheric air pressure through the mold cavity. dual container to any one or more exterior surfaces of the integral stretch blow molded dual container in the region or regions where control of wall stability is required. 11. Method according to claims 8 to 10, wherein the step of stabilizing a side wall of the first container and/or second container comprises the step of inserting at least one flexible wall surface support member into the second cavity. dual container mold and causing at least one flexible wall surface support member to contact a relevant region or regions of the interior surfaces of the integral stretch blow molded dual container. 12. Method according to claim 11, wherein said relevant surface region is the connection region between the opening areas of the mouth of the first container and the second container. 13. Method according to claim 11, wherein at least one flexible wall surface support member has a shaped/formed head shape in this manner to assist with the formation of the desired final inversion conformation/shape in the point of intersection of the inverting and non-inverting walls. 14. Method according to claim 1, wherein at least one of said reversing pistons has a flat thrust face. 15. Method according to claim 1, wherein at least one of said reversing pistons has a completely profiled face that adapts to the final shape of the inner surface of the wall (30, 65) below at least partial of the second container to counteract the inversion of the wall (30, 65) below the second smaller one. 16. Method according to any one of claims 11-15, wherein during the step of reversing the at least one flexible wall surface support member and at least one of said profiled reversing pistons (36) cooperate to extend stretching the length of the wall of the second inverted container. 17. A method as defined in any preceding claim, further comprising, at any point in the production sequence the additional step of cutting one or more portions of the first container (52, 69) and/or one or more portions of the second container and/or one or more portions of the tubular blank (1); I: the additional step of converting any one or more partially closed bottom walls into completely closed bottom walls, wherein this additional step optionally comprises the step of forming a partially or fully closed air gap (34); I: the additional step of further inverting any feature or wall section in any integrally connected vessel (17, 31, 70, 91), wherein this additional step optionally comprises the step of forming a partially or fully closed air gap (34); I: the additional step of adding an additional part or parts of any shape or form to any of the integrally connected containers (17, 31, 70, 91), wherein this additional step optionally comprises the step of forming a partially or fully closed air gap (34); I: the additional step of adding additional material or materials of any form, property or nature to the air gap (34); I: the additional step of applying additional shaping/forming methods to ensure that the inverted container fully assumes its final design shape/shape (95, 96). 18. Method according to any one of the preceding claims, executed so that the resulting double-walled container has a highly uniform average wall thickness (3, 76) significantly less than 0.35 mm, and preferably between 0.10 mm and 0.30 mm . 19. A stretch blow molding apparatus for producing a mechanically inverted double-walled container with the structure of two containers integrally connected (17, 31, 70, 91) and adjacent extending in the same direction (40) with a gap ( 34) of air among them, the device that includes: a first (83, 9) mold with a first (83, 9) mold cavity having the shape of a dual container, designed to receive a thermoplastic tubular blank (1) with a first (83, 9) open end and a second opposite end, said cavity including a large opening recess for a mechanical and/or sealing engagement connection to the open end (2, 93) of the tubular blank (1), a first recess (83, 9) of the cavity of the attachably connected container that includes a mouth opening area (10, 14, 24, 28, 84, 88), side wall areas (11, 15, 25, 29, 85, 89), and a partially closed bottom wall area (12, 26, 86, 90), a second engageably connected container cavity recess that includes a bottom wall opening area (10, 14, 24, 28, 84, 88). mouth, areas (11, 15, 25, 29, 85, 89) of side wall and an area (16, 30) of partially closed or completely closed bottom wall, with the recesses of the container cavity first (83, 9 ) and second extending in directions (39) opposite to each other; a second mold with a second mold cavity having the form of a dual container, designed to receive said dual integral stretch blow molded container, said second cavity including a large opening recess for a mechanical latching and/or sealing connection to the partially closed bottom wall (30, 65) of said first stretch blow molded container (52, 69), a first recess (83, 9) of the cavity of the container connected in a latchable manner that includes an area (10, 14, 24, 28, 84, 88) of the mouth opening, areas (11, 15, 25, 29, 85, 89) of the side wall and an area (12, 26, 86, 90) of the partially lower wall closed, a second recess of the container cavity hookably connected that includes a mouth opening area (10, 14, 24, 28, 84, 88), areas (11, 15, 25, 29, 85, 89 ) of side wall and a partially closed bottom wall area (12, 26, 86, 90), with the first (83, 9) and second container cavity recesses extending in directions (39) opposite to each other, and at least one profiled reversing piston recess (32) engageably connected as part of the wall (30, 65) below the second recess of the container cavity, and optionally including at least one thermal conditioning device for heating the first container (52, 69) or the second container or both of said dual integral stretch blow molded container, and optionally including at least one path (35) for interconnection with at least one source of air pressure below the atmospheric; at least one profiled piston; at least one wall stability device; and a mechanical blank stretcher for mechanically stretching the tubular blank (1) in a direction (63, 94) of the longitudinal axis when it is in a thermally conditioned condition; the apparatus being adapted to carry out the method of any one of claims 1 to 18. 20. Method according to any one of claims 1-18, wherein mechanically stretching the blank has thermal conditioning. 21. Method according to any one of claims 1-18 or 20, wherein the second container is smaller than the first container and where, after inversion, the second container is internal to the first container. 22. Method according to any one of claims 1-18 or 20-21, wherein the first container is smaller than the second container and where after inversion the first container is internal to the second container. 23. Method according to any one of claims 1-18 or 20-22, wherein the first container is inverted and the second container remains at least substantially not inverted.