NL8203448A - METHOD AND APPARATUS FOR MANUFACTURING PRODUCTS ORIENTED ACCORDING TO TWO AXLES - Google Patents

Description

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Method and device for manufacturing products oriented in two axes.

The invention generally relates to a method and device for manufacturing hollow products of thermoplastic material and more particularly to a method and device for manufacturing two-axis oriented products of thermoplastic resin materials. It is generally recognized that the strength characteristics of thermoplastic molded plastic containers and hollow products are materially increased when the thermoplastic material from which these products are formed undergoes molecular orientation.

This orientation can be provided by using pre-oriented stock materials. However, it is preferable to impart molecular orientation in one or more directions to the end products during the forming process of the products.

The most favorable strength properties are achieved when the plastic material is oriented in the walls of the hollow product along two axes in a relatively uniform or balanced manner. The material 20 is oriented along two axes by stretching it proportionally over both coordinate axes of the plane of the material. The two-axis orientation of such a material can be characterized by its very low birefringence value. Carrying out a two-axis orientation, balanced in the coordinate directions, is a complicated task when it is to be carried out in conjunction with the manufacture of a hay product of varying cross-section.

Numerous methods have been used in the prior art to produce hollow products from thermoplastic materials to produce products which exhibit a certain degree of molecular orientation. These methods generally involve a series of separate steps such as forming a preform, pre-stretching the preform, and finally a compression molding step to conform the preform to the final desired shape. Generally, when using conventional methods, the preform (often referred to as "parison") is preformed in one of two ways. One method consists of forming a tubular preform (parison) by an extrusion process and the preform thus formed is then subjected to further molding techniques. The second, more commercially applied method consists of forming the parison (parison) by an injection molding process. After the preform (parison) has undergone an injection molding operation, it is cooled and placed in a separate final molding machine, after which it is reheated and the final molding steps are performed thereon.

One method of forming the final bottle with a dual axis orientation consists of stretching the preform (parison) longitudinally along its axis, while the preform (parison) is at its orientation temperature. This longitudinal stretching is performed with mechanical stretching means. In order to maintain the advantages of the two-axis orientation, both the longitudinal mechanical elongation and the radial elongation must be achieved by pressure methods at the orientation temperature and the product must not exceed the orientation temperature or the influences of the orientation will are neutralized. This procedure has the drawback that the mechanical stretch has a non-uniform character and no balanced orientation along two axes is achieved. This is especially true along the leading edge of the machine strain gauges promoting a state known as the "leading edge effeet". A considerably greater elongation and deformation occurs along this edge 30 than in regions far from the edge. Also, in the leading edge region, unfavorable thinning of the material can take place, which degrades the quality of the finished container.

In a similar process, a two-axis orientation is achieved in the preformed parison by subjecting it to a first blow step to provide a pre-blown product, the shape of which is substantially similar to that of the final article, but has smaller dimensions. This preliminary blowing operation is performed while the material is above its orientation temperature, so that no molecular orientation takes place in the material. The two-axis orientation is then performed when the preformed product is subjected to a final blowing operation step at the orientation temperature.

Other biaxial orientation of a hay product utilizes a biaxial oriented material from which the final product is formed by a vacuum or blow molding process. This process has the disadvantage that the orientation of the material is adversely affected during the thermoforming step. Also, this type of two-axis orientation is difficult to control in objects with an asymmetric cross-sectional configuration or with an axial configuration.

There has long been a need in the manufacture of containers for a thermoformed thermoplastic container which can be satisfactorily used for packaging liquids and solids and is also suitable for keeping them fresh and sterile. Such containers must meet several strict criteria. They must have sufficient strength to withstand the internal pressures of the pressurized drinks and / or the mechanical stresses during transportation and the resulting rough handling and dropping of the package. Furthermore, the container must have an attractive appearance and be non-toxic. In many cases the container must exhibit good sealing properties against the diffusion of different gases from or into the products stored in the container. For example, containers that store both solid and liquid food products must have relatively strong closures against oxygen infusion from the surrounding atmosphere.

Likewise, carbonated drinks such as beer and non-alcoholic drinks must exhibit good sealing characteristics against the diffusion outward of the pressurized carbon dioxide trapped in the liquid stored in the container. It has been found that a loss of only 15% of the total carbonic acid content of non-alcoholic beverages makes these beverages tasteless for the user. The closures of the containers stocked from thermoplastic materials must therefore be very good in the field of oxygen and CO2 closures.

There are currently some containers of plastic material 5 on the market containing carbonated drinks. Some non-alcoholic drinks have been marketed in plastic bottles: 1 or 2 liter capacity. These bottles, which are made of polyethylene terephthalate (PET), do not provide sufficient storage time to complete the consumer. io to satisfy. There is a strong demand for smaller bottles from 200 g to half a liter. Unfortunately, as the bottle size is reduced, the sealing properties deteriorate due to the larger surface area / volume ratio of the smaller containers.

Also, the processes used to manufacture 1 or 2 liter non-alcoholic beverage bottles which are currently on the market are very complicated and expensive due to the many associated processing steps in forming the containers. These procedures use a preform ..: 20 (parison), which has undergone an injection molding step in a first independent operation, then cooled and then subjected to a separate operation, heating the preforms and stretching with a machine forceps and then thermoformed into the final containers. Furthermore, the strength of the thermoformed 1 or 2 liter bottles leaves much to be desired in the bottom end area, where the maximum mechanical stress occurs. Therefore, the bottles are constructed with a basically hemispherical bottom end to provide a sufficient mechanical strength therein. This in turn makes it necessary to provide a separate base at the bottom end to provide a flat bottom surface for the bottles so that they can stand upright separately. In addition, the bottom feet provide an extra strength in the weaker part of the container. The use of injection molding techniques to form preforms virtually eliminates the possibility of forming multilayer walls in the containers to provide different properties of the containers. For example, it may be desirable to provide the container with a multi-layer wall, 8203448

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Wherein one of the layers provides strength to the wall, a second layer provides the necessary sealing properties, and a third layer provides the desired aesthetic appearance to the container. It is not known how such multi-layer containers could be uniformly formed by a procedure in which the preform is subjected to an injection molding technique.

Furthermore, it is a very costly and time consuming operation due to the high number of processing steps in the conventional beverage container forming process.

According to the invention, there is provided a method and system for manufacturing biaxial hollow thermoplastic products in a simplified and very fast, yet efficient process. Furthermore, according to the invention, a very efficient device is provided for forming a two-axis oriented hi product of a multilayer thermoplastic material.

The method and system of the invention uses a high pressure thermoforming system, in which tire material is subjected to a downward blowing force to form the preform, which is then cooled for a period of time, after which a upward pressure is exerted on the preform to expand it to the final shape of the product. The described assembly uses hydraulic pressure to press the tire material and a set of upper and lower mold cavities containing porous shaped metal or other metal structures suitable for gas to flow therethrough. The system described also utilizes a valve system consisting of a six-way valve and an air system consisting of a compressed air source and a pair of air collection reservoirs herein. The top and bottom mold structures use interchangeable mold sections to form products of different shapes according to the special needs and requirements of the container manufacturer.

According to the invention, use is made of a high-pressure thermoforming system as opposed to the conventional vacuum forming system of the prior art 8203448. The construction makes it possible to mold the preform and then mold the final product in the same device. As a result, the expensive forming technique of forming the preform according to the conventional thermoforming method is superfluous. Furthermore, the construction according to the invention enables balanced orientation along two axes of the end product, which greatly increases the strength and sealing properties. Finally, the invention makes it possible to use multi-layered co-extruded fiber material as a supply stock, whereby a very uniform, multi-layered, two-axis oriented thermoplastic container can be obtained with the desired qualities with regard to the strength, aesthetic and sealing properties.

The invention will be explained in more detail below with reference to the drawing, which shows by way of example an advantageous embodiment of the device 20 for manufacturing hollow products and some forms of these products. Herein: fig. 1 schematically shows a favorable embodiment of the device for carrying out the method according to the invention, fig. 2, 3, 4 and 5 schematic representations of the orienting thermoforming processing steps of the method according to the invention, fig. 6 is a perspective view of a group of axial-oriented hollow articles formed from a strip material thermorun, manufactured according to the method according to the invention, while they are not yet separated from each other, FIG. 7 is a perspective view of a preforming surface, usable in the procedures according to the invention, fig. 8 in perspective a bottle of plastic material, manufactured according to the invention, fig. 9 in perspective another form of a container, manufactured with the method according to the invention, fig. 10 schematically a front view of a thermoforming construction, Fig. 11 schematic; a side view of the construction 8203448 t ...

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Fig. 1, fig. 12 schematics]! a top view of the construction of fig. 1 and 2, fig. 13 partly a cross-section and partly a front view of the mold blocks of the thermoforming construction, fig. 14-19 different top views of removable molds, fig. 20 schematically a view of the pressure valve system, fig. 21 a cross-section of a valve used in the pressure valve system, fig. 22-24 different isometric representations of a valve element for use in the valve of fig. 12, fig. FIG. 24 is a modified embodiment of a mold for manufacturing a container top end, and FIG. 26 is a schematic of the hydraulic and electrical control chains for the entire system.

According to the invention there is provided a method by which hollow thermoplastic products are blow molded in a single molding step, which products are characterized by an optimum degree of orientation along two axes. This process can be operated with very short cycle times, which means that the hollow products can be produced in series at very high speed and low cost.

The process of the invention is generally applicable to any type of thermoplastic resin material, which can be extruded in strip form and can be thermoformed. Both crystalline and amorphous polymers can be used in the process of the invention. Examples of suitable types of polymeric materials include polyesters such as polyethylene terephthalate, vinyl aromatic or styrene polymers, including both substituted and unsubstituted styrene polymers and copolymers, highly impact resistant polystyrenes, including styrene-rubbery polymer blends, graft copolymers and block copolymers and resins of the ABS type, polyolefins, such as polyethylene and polypropylene, nitrile-containing resins -. . such as copolymers, 8203448-8 which contain as main ingredient acrylonitrile, acrylic materials such as polymers and copolymers of acrylic and methacrylic esters, vinyl esters such as polyvinyl chloride and vinylidene halide polymers, polyamides and various blends of these well known classes of polymeric materials.

The thermoplastic properties of these classes of polymers are sufficiently known to those skilled in the art. For each particular polymer, there is a so-called "orientation temperature range" or "reflux range" within which the polymer can be molecularly targeted after stretching. This range is slightly below the melting temperature of a polymer melting at a certain temperature, or below the crystal melting range of a polymer melting above a temperature range. The orientation temperature range is also above the second order glass transition point, this is the temperature at which a substantially amorphous polymer or a crystallizable polymer, which can be cooled as an amorphous polymer, transitions from a glassy state to a rubbery state. In this rubbery state, the polymer can be stretch-oriented in the form of a film.

The orientation temperature range will be different for each type of polymer, but this can easily be determined by simple experiments or, in the case of a large number of polymers, searched from the many available reference sources. A representative list of polymer types with their associated orientation temperature ranges is given in British Pat. 921,308, after which reference is made to this.

The basic process of blow molding is known in the art of manufacturing hollow products, but this procedure is not suitable for the production of two-axis oriented products. The introductory part of the specification describes the particular procedures which are used in the prior art for the manufacture of oriented hollow products. A typical blow molding machine is suitable for only very limited operating conditions, such as a blow pressure of only about 7 to 10 kg / cm. These conventional machines are not suitable for carrying out the procedure of the invention without being modified in order to provide higher blowing pressures and in other ways as will be explained later. I is schematically shown an apparatus in the form of a production row for carrying out the method according to the invention. Initially, there is a source for supplying a thermoplastic film or thermoplastic sheet such as a roll 10 with a poly-10 multi-web 12. This supply source of sheet material 12 may also consist of an extruder during the execution of the process §D§ continuously supply the polymer sheet.

The sheet material is then passed through a heater 14, which is adapted to raise the temperature of the polymer material of ΊχβΕ v.el · to a value above its second order glass transition temperature or its soaking temperature, but which slightly lower than the melting temperature or melting range of the polymer.

The heated thermoplastic sheet is then fed into the blow molding device, which is schematically indicated by reference numeral 16. The blow molding device is characterized by an upper mold part 18 and a lower mold part 20, which are movable relative to each other so as to have a number of mold cavities 22 to be opened and closed. After opening the top and bottom mold parts, the sheet of thermoplastic material is placed between the two mold parts and then a pressure difference is established on one side or the other of the plastic sheet to drive the sheet into the mold cavities and subject it to thermoforming until the desired shape is achieved.

According to the invention, the blow molding device 35 is provided with a number of specially designed cavities 24 in the mold part opposite the mold part, which contains the mold cavities 22. A specially designed cavity 24 is positioned opposite each mold cavity 22. Each special cavity 24 is provided with a preform die surface with a predetermined configuration. A favorable embodiment of 8203448-10- such a preform surface, which is suitable for forming hollow, generally cora-shaped products of polyethylene terephthalate (PED), is shown in fig. 7.

The configuration of these surfaces is not critical according to the invention and surface configurations generally similar to those shown in Figure 8 can be satisfactorily used to form other types of thermoplastic material. A certain shape is imparted to these surfaces in order to optimize the uniformity of the wall thickness of the hollow product after it has been blow molded.

The surfaces of the preform mold parts 24 primarily serve as heat exchange surfaces. After being placed between the mold parts 18 and 20, the thermoplastic sheet is blown against the surfaces of the preform mold parts 24. After the polymer sheet is kept in contact with these surfaces for a predetermined period of time, which depends inter alia on the temperature at which these surfaces are held, the polymer sheet is blown into the mold cavities 22 by forming a positive pressure difference on the side of the sheet 12 opposite the mold cavities. After this, the mold parts are opened and the sheet subjected to blow molding is moved out of the device. The individual shaping steps will be explained in more detail with reference to FIGS. 2-5.

When the sheet exits the blow molding device 16, a number of hollow blow molded products are formed therein, which are joined together through non-thermoformed bar pockets of the sheet 12. The hollow products may all have the same shape or as shown in Figure 1, some of the products may be of a particular configuration such as, for example, a bottle top portion 26, while the remaining 35 of the hollow products may have a different configuration such as, for example, a bottom bottle portion 28 which is suitable to fit on the bottle top end. This hollow product sheet is then fed into a suitable cutting device 26, in which the interconnected 40 hollow products are separated from each other and stripped of thermoplastic waste material, which may be, for example, fed to an extruder for recovering the thermoplastic sheet material 12.

The cut hollow products exiting the cutting device 30 can be used as cups or containers for food products. Since such a container can be efficiently manufactured with walls oriented along two axes, it is possible to further reduce the thickness of the container walls without loss of strength properties. The amount of thermoplastic material used per container can therefore be reduced, thus saving material costs.

The hollow products exiting the cutting device can also be further processed into more refined type containers. As shown in FIG. 1 and more in detail in FIG. 6, after the bottle top end part and bottom bottle part are formed in the blow molding operation step, the bottle parts can then be assembled into whole bottles. This can be advantageously achieved by inserting the bottle parts into a so-called rotary welding device 32. Here the holder parts are placed in axial direction against each other until they together provide the desired end configuration, after which the respective parts are quickly rotated relative to from each other to provide sufficient frictional heat to fuse or weld the two parts together. Such procedures, as well as suitable devices for carrying them out are described, inter alia, in U.S.A. patents no. 3,216,874, No. 3,220,908, no. 3,297,504, no. 3,316,135.30 Re. 29,448, No. 3,499,068, no. 3,701,708 and No. 3,759,770.

In a favorable embodiment according to the invention, after a top bottle half and a bottom bottle half are welded together, a configuration as shown in Fig. 8 is obtained.

In a further embodiment of the invention, each of the mold cavities 22 in the blow molding device 16 has the same configuration, corresponding to that of the entire top and side wall portion of a bottle-shaped container as shown in Fig. 9. After leaving the cutting device 30, these bottles can be further treated in many ways without bottom parts. If they are provided with a suitable bottom to top-end tapered portion, some of these products can be placed in the following. In this manner, a number of empty containers can be fed in a given space (eg a truckload is multiple folded compared to normal empty bottles). Moreover, such products with or without such a tapered part lend themselves excellently to high-speed printing processes, since the hollow products can be slid over a spindle to provide sufficient support for a high-speed rotating print head. to apply with the force necessary for good quality printing. The hollow bottles without bottom can be subjected to a rotary welding operation either directly after leaving the cutting device, or after having undergone one or more intermediate processing and / or transport steps in order to obtain a generally flat bottom wall therein. to confirm. A bottle-shaped container as shown in Figure 9 is the result.

In Fig. 2-5, the combined blow molding and biaxial orientation step takes place in the blow molding device 16 as will be explained in more detail below.

In FIG. 2, the sheet is moved to the space between the upper mold part 18 and the lower mold part 20, which mold parts are separated from each other at this time. The sheet 12 has just exited the heater 14 (FIG. 1), which may consist of a conventional oven such as, for example, an infrared oven of the type 30 used in blow molding machines. The temperature will of course depend on the type of thermoplastic material from which the sheet 12 is formed. In the case of a sheet of PET material (e.g., 1.1mm thick), the oven can be maintained at a temperature between about 610-630 ° F. The sheet 12 enters the heater and remains therein for several cycles of the machine while the sheet is fed stepwise through the heater toward the blow molding machine 16.

A satisfactory residence time for the sheet of PET material 40 in the heater at the above temperatures 8203448-13 is about 2 minutes. This is sufficient to heat the sheet 12 to a temperature above its softening temperature, but below its melting temperature. Suitable temperatures and residence times for other types of sheet material can be easily determined.

As shown in Fig. 3, the upper and lower mold parts are then closed relative to each other to firmly clamp the sheet 12 therebetween. Although not shown in more detail in FIG. 3, when the die sections are closed, the sheet 12 will initially be moved upward with its center section through the surface 50 on the lower mold sections 24. This will cause the sheet 12 to tend to rise so that it contacts only the upper surface portion 50. Subsequently, three-way valves 34 located beneath each of the lower cavities 24 are actuated to provide a connection path between the space within the blank 24 and a vacuum line 36, which may be connected to a vacuum source if desired. At the same time, three-way valves 40 are operated to connect a pressurized gas source, which preferably supplies air, through conduits 44 to the space within each upper cavity 22. This causes the sheet 12 to contact the convex surface 50 by the blowing air. of the lower mold parts 24.

Fig. 7 shows two suitable configurations for the surface 50. These configurations are suitable for forming the container parts shown in Fig. 2-6.

The first surface takes the form of a shallow concave indentation with a centrally positioned, slightly "frusto-conical" cylinder with a rounded top edge and generally flat top projecting upwardly from the bottom of the concave indentation. . The first surface is particularly suitable for forming a partially longitudinally oriented thermoplastic preform suitable for final manufacture into a two-axis oriented bottom portion for the bottle shown in Fig. 8. The second surface is in the form of a shallow concave indentation, from the bottom of which projects a centrally disposed, rounded, semi-elliptical bump 8203448-14 with a generally planar central top. This second surface is particularly suitable for forming a partially longitudinally oriented thermoplastic preform suitable for final manufacture into a two-axis oriented bottle top end shown in FIG. 8. To form the threaded portion, it is advantageous to provide a series of concentric rings or other surface configurations in the flat central top end portion to maintain a sufficient amount of polymer in this location. The configurations of the partially oriented preforms serve to provide a very uniform wall thickness in both the top and bottom bottle sections when the respective bottle sections are blow molded to their final shape.

The surface 50 of the lower mold part 24 is at a temperature lower than the temperature of the sheet 12 when this sheet exits the heater 14. The surface temperature 50 is selected in combination with the time period during which the sheet 12 remains in contact with the surface 50 to impart to the sheet 12 the optimum temperature for a two-axis orientation of the sheet during the next processing step. wherein the sheet 12 is blown into the upper mold cavity 22. In the example of a sheet of PET material described above, a temperature of about 200 ° F for the surface 50 is suitable for bringing the material to its orientation temperature with a contact time between 0.2 and 0.4 sec. Other surface temperatures and contact times can be easily determined.

When the sheet 12 is initially blown against the lower mold part 24, the sheet is at a temperature which is preferably higher than the optimum orientation temperature range for the material, although this should not necessarily be the case. At such a higher temperature, the sheet can be blown against the surface 50 with a relatively low pressure difference of, for example, 2.8 kg / cm. The pressure difference will typically be at least about 2 2 5.6 kg / cm and may rise to about 14 kg / cm. Also, under certain circumstances, for example, at an 8203448-15 surface area, surface area 2 can be worked with a pressure of up to about 24.5 kg / cm. The latter pressures are, of course, considerably higher than the pressures used in conventional blow molding processes. During the initial blow molding step against the lower portion 24, the sheet is typically not oriented along two axes or at least not to any appreciable degree. Some degree of orientation will take place continuously, but is primarily SS axial in the longitudinal direction.

After the sheet 12 has cooled to the desired temperature in contact with the surfaces 50, the three-way valves 34 and 40 are operated to reverse the pressure differential across the sheet. Very high pressure gas is introduced into the lower cavities 24 through conduits 38 as shown in FIG. 4. At the same time, the pressure in each upper cavity 22 is relieved via lines 42, which may optionally also be connected to a vacuum source. Preferably, all gas air is used under a pressure of at least 14 kg / cm and up to about 70 kg / cm. A pressure between about 14 and 49 kg / cm is preferred, due to the fact that the molding device must be very compact in order to tolerate the higher pressures.

Such a massive device is not only expensive, but also not very suitable for very fast cycle times, which can be achieved with the process according to the invention. Very suitable results can be achieved by using an air pressure between approximately 17.2 and 28 kg / cm.

The pressure differential to be applied across the sheet 12 to drive the sheet into the mold cavities 22 must be sufficiently high to provide a uniform bi-directional orientation of the thermoplastic material. Namely, the blowing of the material must be very rapid and complete to form a fully formed container with walls of uniform thickness. Furthermore, the pressure cannot be too high, otherwise this uniformity could be adversely affected. The temperature of the inner surface of the mold cavities 22 is simply selected low enough 40 to rapidly bring the sheet material 12 below its softening temperature, for example below its second order glass transition temperature.

The above temperature and time setting considerations are determined to some extent by the total cycle time for the device. One of the important advantages of the process according to the invention is that the hollow products can be formed at very high speeds.

It is therefore possible to run the procedure with Xage cycle times of approximately 1.2 seconds, this is from the input 10 of the sheet 12 to the output of the formed product and the input of a new sheet section 12. Even cycle times of more than 6 sec. are faster than the conventional procedures for forming bi-directional hollow products. Typically, the process 15 proceeds with cycle times of about 1.5 or 2 sec. up to approx. 4 sec.

This means that the contact time between the sheet 12 and the surfaces 50 of the lower mold cavities 24. is very short, for example on the order of about 0.2 to about 0.4 sec. However, this does not mean that there are 20. no shorter or longer contact times can be used if the appropriate temperatures are chosen for the sheet material and surface 50. However, using longer contact times offers no advantage, but only the disadvantage of lower cycle times.

Fig. 5 shows the final processing step of the blowing process. The top and bottom molds 18 and 20 are separated from each other and the molded sheet 12 containing a number of top bottle parts 26 and a number of bottom bottle parts 28 is released from the mold cavities 30 and passed out of the former. Part of the sheet 12 is shown in perspective in fig. 6. After welding of the upper and lower bottle parts by rotary welding, a finished bottle is obtained as shown in perspective in Fig. 8.

It is clear that for the upper mold cavities 22 any desired shape can be chosen, depending on the shape of the hollow product to be manufactured. A modified embodiment of the bottle is shown in perspective in fig. 9. The entire top portion 60 of this bottle including the threaded neck 8203448-17-22 is formed by the blow molding process of the invention. Because the walls are slightly tapered upwards, the bottomless holder parts can be pressed together for transport and storage. After this, the bottom part 64 can be added by means of a rotation or spin welding process.

A further advantage of the invention is that it opens up the possibility to use specially prepared material sheets, which can be manufactured by known multi-extrusion and co-extrusion processes.

For example, it is possible to use multi-layered co-extruded sheets containing at least one layer of plastic material with good sealing properties, such as, for example, Saran, polypropylene, high-density polyethylene, nitrile-containing polymers, ethylene-15 vinyl alcohol (EVAL) and Barex. The barrier layer may be on one surface of the multilayer sheet or interposed between other layers of different polymer materials. For example, it is possible to place a layer of EVAL with a thickness of 125 microns between two PET layers with respective thicknesses of 625 and 375 microns. These multi-layered sheets can be oriented along two axes without any problems using the process according to the invention.

Fig. 10 schematically shows an end view of a thermoforming construction, which is denoted in its entirety by the reference numeral 100. The device 100 comprises a foot 101, on which a bottom part 102 is placed, to which upwardly projecting arms 103 are mounted, between which arms 103 a transverse beam 104 extends transversely, which runs parallel to the top of the lower part 102.

A lower die block 105 is fixedly mounted in a mounting bed 106, which is attached to the base 102. An upper die block 107 is placed above the block 105 in a vertically movable position and suspended from the cross beam 104 via hinged connecting parts 108. Guide rods 109 provide lateral stability to the movable upper die block 107.

A power source such as a hydraulic cylinder 110 is disposed between cross beam 104 and die block 107 8203448-18 and attached to both.

Instead of the hydraulic cylinder arranged as the power source between the movable upper die block and the fixed cross beam 104, other known means for exerting downward pressure and movement on the die block 107, such as a mechanical driving unit, which can be electric or pneumatically driven. The cylinder 110 is mounted on a fixed shaft 111. A movable plunger 112 exits the cylinder and connects it to the die block 107. Additional downward pressure forces can be applied by attaching additional compression cylinders to the pivot arms 108. Additional power sources to the arms 108 provide a more uniform pressing force on the die block 107 in order to efficiently press this block 107 onto the block 105.

Close to the lower die block 105, a pressure reservoir 113 is provided to provide a sufficient amount of air pressure for the thermoforming operation in the upper dies. The reservoir 113 provides a reserve pressure capacity for storing an initial air pressure charge to efficiently supply air to each of the mold cavities in the mold. Similarly, in the device 100, a second collection reservoir 114 is mounted and connected via an air line 115 to the upper die block 117 to store compressed air and provide operating air pressure for the thermoforming operation performed in the lower die cavities.

Fig. 11 shows a side view of the thermoforming device 100 with schematically shown and thermoforming auxiliary device 120. As can be seen from the side view of Fig. 11, the bottom part 102 consists of an elongated table, on which a series of rollers 121 are rotatably mounted, 35 which rollers driving a toothed chain 122. The chain 122 is an endless chain which engages the teeth on the rollers 121 and further includes upwardly projecting teeth which engage the material sheet and drive this sheet through the thermoforming device 40. In addition to the chain roller assembly mounted on the bed 102, a portable furnace assembly 123 is provided which can be moved close to the bottom. : and above the chain roller construction 121-122. The upper heating part of the oven 123 is shown above the 5 rollers and the lower heating part 124 is shown in dashed lines in Fig. 11 below the rollers.

Attached to the rear end of the bottom member 102 is a sheet holding arm 125 with an upwardly projecting arm on which the reel reel 126 is mounted, upon which a large roll of plastic sheet material 127 is rotatably retained.

The supply roll 127 passes a layer of plastic sheet material 128 over the rollers 121 and the upwardly projecting teeth 122a of the pair of endless chains 122 pierce the sheet 128 and hold it in the device 100.

A motorized power source (Fig. 26) drives a pair of toothed rollers 129, which in turn, through the intervention of external teeth, engaging the chains 122, provide driving force to drive the tooth chains 122 in the direction of rotation according to the clockwork in fig. 11. As a result of this, partly due to the action of the teeth 122a, the sheet 128 will be driven into the heating member 123 of the device. By controlling the speed of the motor driving the rollers 129, the heating and speed of the sheet 128 through the oven 123 can be controlled. At the end of the device 100 remote from the roller 126 is placed a product cutting device 130 consisting of an upper movable cutting head 30 131 which is movable in the vertical direction and serves to remove the finished products from the sheet 128 when this sheet exits the former 105, 107.

With a control panel (FIG. 26) using semiconductor or microprocessor chains, all different mechanical and pneumatic operations of the device 100 and the cutting device 130 are controlled. This control panel is therefore operatively connected to the feed gear for the toothed rollers 129, the pressing action of the cylinder 110, the compressed air supply to the storage reservoirs 113 and 114, the 6-way 8203448 -20 valve system (to be described in more detail). ) and the cutting device 130, 131. The control panel uses known control systems which are commercially available. Preferably, all operating parameters of the system can be programmed in the control panel and varied independently to achieve maximum operating efficiency of the entire device. The preferred controlled parameters include the velocity of the sheet 128, which is directly proportional to the velocity and timing of the drive rollers 129, the timing of actuation of the cylinder 110, the timing and magnitude of the air bursts from the reservoirs 113 and 114, the movement back to the lifted position of the cylinder 110, and the cutting action of the product cutter 130, 131. Additional parameters include the amount of heat generated in the furnace 123, 124 and the compression force, achieved in the upper die block construction 107, 108, 110. Another critical parameter is the residence time of the thermoformed sheet in both the lower die 105 and the upper die 107.

Depending on these residence times, the total time that the die 107 is pressed down on the die 105 by the action of the cylinder 110 and the arms 108. Other parameters, which are related to the residence times, the compression force and the temperatures, include the thickness of the thermoplastic material, the composition of the material, and whether or not the sheet material is a single resin or a coextruded sheet of two or more interconnected resin layers. The molding pressure should normally be adjusted upwards if a thicker sheet is formed. The optimum molding pressure for each sheet thickness can be determined without many tests by running through several cycles of the system and varying the molding pressure to obtain optimal molding operations.

Fig. 12 schematically shows a top view of the device 100, with the top side of the oven 123 being visible and the rollers 121 and endless chains 122 shown schematically in dashed lines.

This top view further shows the top of 40 the die block 107 with the actuating cylinder 110 and the arms 108 removed to indicate the entry of the compressed air lines into the top and bottom die blocks. the cutting device 130 is removed to show the separate cutting blades 132 for cutting individual products.

Fig. 13 shows the die block assembly 105, 107, with the individual die units removed.

The die block construction consists of a generally elongated, rectangular metal block portion 107a and a lower block element 105a of similar shape. Each block element includes a number of cavities 107b and 105b formed therein.

A second group of cavities 107c and 105c are also formed in the top and bottom blocks. These cavities are generally cylindrical or of other symmetrical shape and are suitable for receiving separate mold units, which are placed snugly into the cavities and provided with locking means such as "alien" head screw bolts or other type of screw bolt, it passes through blocks 105 and 107 and protrudes into cavities b and c. The cavities are further provided with air inlet channels d for supplying thermoforming compressed air to the mold units.

Figures 14, 15 and 16 show different views of the preform die units suitable for placement in the cavities 105b or 105c of the lower die block 105. Figure 15 shows a cross section of the die cavity unit, which consists from the generally cylindrical housing portion 140, which is formed to fit snugly into δέη of cavities 105c or 105b. Although a cylindrical housing part has been used for the mold 140 because it is easy to manufacture, other shapes such as a rectangular, cubic, triangular prism, etc. are also suitable, the shapes of the cavities 105b and 105c being coraplementary thereto. . An upwardly projecting collar portion 141 is integrally formed with the housing 140, while a lower tubular portion 142 is formed at the end of the housing remote from this collar portion 141. The tubular portion 142 is circumferentially provided with an annular clamping groove 40 143 for receiving clamping screw bolts passing through the die block 105. A saucer-shaped part 144, which is anchored in the housing with teeth, consists of the inclined walls 144a and a relatively flat bottom part 144b, along the top part of the mold 140.

In the collar 141, pressure closing grooves 145 are cut over its circumference or more.

An upwardly protruding preform center portion 146 is generally located centrally in the tray portion 144 and secured to the die 140 by a long central bolt 147 passing through an opening 148 positioned centrally in the tray-shaped region 144. At the lower threaded end 144 of the bolt 147, a threaded nut 149 is disposed which abuts the underside 151 of the bottom surface 144b to retain the bolt 147 and the top center portion 146. The bolt 147 has an end distal to the threaded end 150 and a diametrical head portion 151 which abuts and depresses the center portion 146. The bore 152 through the center portion 146 preferably has a slightly larger diameter than that of the bolt 147 to allow air to pass therebetween. The center member 146 may be formed of porous metal such as bronze or aluminum, which is specially manufactured to provide connecting pores 25 therethrough, or may be made of a solid material such as aluminum or copper, through which there are a very large number of air channels drilled. Likewise, a group of air channels 153 are formed in the tray portion 144b by drilling or other processing.

Fig. 14 shows a bottom view of the die 140, showing the lock nut 149, the bolt 147, 150 and the bottom 151 of the flat portion 144b. Furthermore, the air passage channels 153 are shown in Fig. 14. Fig. 16 shows a top view of the preform die of Figs. 14, 35 and 15. More specifically, in Fig. 16 the die 140, the clamping groove 145, the inclined wall 144a, the flat disk portion 144b and the vertical center portion 146 have been a cone-conical configuration, as well as the bolt head 151, with which the frusto-conical upper center 40 portion 146 is attached to the die housing 140.

8203448 -23-

Fig. 17 shows a modified mold configuration suitable for use in the lower mold block 105. This mold uses the "negative" preform configuration as opposed to the "positive" configuration of FIGS. 14-16. In the embodiment of Figure 17, a die housing 160 is formed of a cylindrical or other regular geometric cross-sectional configuration suitable for a snug fit into the die block cavities 105c of the die block 105. The housing 160 includes an outwardly projecting collar portion 161, which is provided with two V-shaped pressure retaining grooves 162. The top surface of the die 160 includes a saucer portion 163, which has an annular recess running around the top surface of the die.

The central portion of the mold includes a slightly elevated shoulder portion 164 of circular configuration defining the edges of a "cratered" negative mold cavity 165. The cavity 165 extends downwardly along almost the entire length of the housing 160, and has a cup-shaped bottom end 166 through which a number of air channels 167 are formed. The housing 160 further includes a lower saucer-shaped annular region 168 which encloses the cup-shaped bottom end 166 and extends upwardly into the housing 160. A plurality of air channels 169 further pass through the housing 160, connecting the upper saucer-shaped area 163 with the lower connecting saucer-shaped area 168. The housing 160 further includes a circumferential annular clamping groove 160a for receiving one or more clamping screw bolts passing through the die block 105 to clamp the die 160 in the die cavity.

Fig. 18 shows a cross-sectional view of an assembled upper mold structure 170, which is constructed from three separate parts for manufacturing engineering reasons, but could also be formed from a single, one-piece material part. The die 170 is preferably formed from an easily machined material such as copper or aluminum, but may further comprise any acceptable solid heat resistant material. The die-40 construction 170 includes an upper housing portion 170a, a lower housing portion 170b, and an air duct inner ring 170c. The top portion 170a is attached to the bottom portion 170b by a threaded cylindrical connector 171. The top housing portion 170a includes an inwardly protruding annular shoulder 172, which forms a downwardly facing stop shoulder for the ring 170c. The lower housing portion 170b also includes an upwardly facing annular shoulder 173, which forms the lower seat for the ring 170c. The positions of the shoulders 10 172 and 173 are such that when the threaded connector 171 is screwed on, the ring 170c is held snugly between the two shoulders. The ring 170c is preferably formed from a porous metallic material such as porous bronze or porous aluminum to provide a wide area with an air flow capacity. Passages 174 provide communication across the top casing wall 170a to an annular air passageway 175.

A group of small serrations 170e are formed about the periphery on the inside of the mold in the wall of the cavity 178 to form projections on the outer surface of the finished containers. These protrusions may be placed in similar serrations to the heads of a spin welding system to grip the containers and prevent them from slipping in the spin welder during spin welding operations thereon.

A second annular clamping groove extends about the periphery of the upper housing portion 170a to receive threaded clamping means such as bolts or allen screw bolts, which pass through the upper die block 107. Likewise, at the upper end of the mold part 170a, an upper cavity 177 is formed which communicates with an open bore 178 within the mold through numerous air passageways 179 drilled therethrough.

A mounting collar 170d extending on the outside is further formed on the lower mold part 170b.

The mold 170 is an upper mold for placement in an upper mold block 107 and provides the final configuration of a lower container portion, 8203448-25, while the molds of Figs. 5-8 are preform dies used in forming an intermediate step of the product to be manufactured.

Fig. 19 shows a cross-sectional view of an embodiment of an upper die 180 suitable to fit snugly into an upper die block 107, While the die 170 was specifically intended to form a lower holding member, the die 180. Capable of forming an upper container portion which is later joined with the lower container portion formed in the die 170. The die 180 includes a single, one-piece lower portion 181, over the circumference of which a mounting collar 182 extends. The internal cavity 183 of the die 180 is in the form of an upper container 15.

Across the periphery of the wall of the die 180, an annular clamping groove 184 is formed to receive a clamping screw bolt that passes through the die block 107 and engages the groove 184. Through the wall 20 of the die 180 A number of air vent channels 185 are formed to allow the air entrained in the mold by the thermoformed plastic product. Over the lower part of the mold cavity 183, a number of serrations 186 are formed in the wall of the mold to provide small projections to the molded product, which serve as engaging parts in a spin welding machine.

At the upper end of the die assembly 180 are placed a pair of sliding threaded die members 187 and 30 188 which move together in the direction indicated by the arrows to provide an upper threaded die cavity 189 to form the threaded top end portion of a bottle or other container with a threaded cap. The threaded mold parts 187 preferably slide over the top end of the mold 180 and together generally comprise a cylindrical threaded mold cavity 189. The threaded mold parts 187 and 188 can be operated with conventional actuating means such as air cylinders, hydraulic 8203448 -26- cylinders, cam disc members, a chain drive, etc. When the upper holder part is thermoformed in the cavity 183 and has hardened sufficiently, the upper mold parts 187 and 188 are driven in the direction opposite to the arrows, so as to detach the top threaded die parts from the completed threaded portion of the upper holder portion.

The upper die 180 is a modified embodiment shown in FIG. 25, which is designated in its entirety by the reference numeral 190. The die 190 corresponds to the die 180 in all areas except for the thread-forming portion at the top end of 1. do die. In the'; mold of FIG. 25, the housing portion 191 extends all the way to the top end of the mold construction. The threaded portion of the container is formed using a spinable or rotatable thread-forming jacket 192, which is rotatably mounted in the upper portion 193 of the container. the die 190. The thread-forming sheath 192 may have a cylindrical configuration and fit snugly into a cylindrical opening in the mold 190. A cavity 192a is formed in the sheath 192 to correspond to the completed thread configuration of the top bottle or holder part. A drive shaft 194 is integrally attached to the top of the shell 192 on its centerline. Attached to the shaft 194 is a drive gear 195, which imparts a rotational motion to the casing 192. The casing 192 includes projecting female threaded parts 196 with a configuration that is complementary to the desired threaded configuration of a completed upper container part. . The die 190 is further provided with a mounting collar 197 and internal serrations 198, similar to that of the die 180.

Figures 21-24 show different views of a single three-way valve 200. The valve 200 shown in Figure 1 consists of a generally rectangular block 201 to which a gland or flange plate is attached by screw bolts and in block 201 a generally hemispherical inner cavity 203 is formed. Air-40 flow lines 204a, 204e and 204m extend outwardly and 8203448-27 are in a planar relationship with the three walls of block 201. These channels may have any cross-sectional shape, but in the example shown, they have manufacturing engineering reasons a cylindrical shape.

On the fourth side, located in the same plane, there is an opening through which a valve member 205 passes. with an upwardly extending shaft 205a and a valve ball 205b.

Figures 22, 23 and 24 show different views of the valve member 205. A valve 906, which bends through 90 °, consists of a downwardly extending duct section 206a and a laterally extending duct section 206b, through the center of the valve ball 205. These lateral and downwardly extending channel arms terminate at the ball wall 205b in ports 207a and 207b. The closure of the lines 204a, 204e and 204m is effected by rotation of the shaft 205a in the direction of rotation as indicated by the arrow in Fig. 21. The channel arm 106b is then rotated from the position in which it communicates with the line 204a, over which compressed air is supplied to the valve 201, by 180 ° to the position E (line 204e) in which a connection is made to the air exhaust system. In both positions, the conduit 204m remains in constant communication with the downwardly directed channel arm 206a. Thus, in the position shown in Fig. 21, the conduit 204m, which is attached to the spritit piece, is communicated via channel 206 to the air exhaust system through conduit 204e. By rotating the shaft 205a through 180 °, compressed air can be supplied from the line 204a to the manifold through the line 204m.

In FIG. 20, a pair of three-way valves of the type shown in FIG. 21 and denoted 200 and 210 are combined in a single housing portion 220. The housing portion 220 forms a main housing portion with a generally central recess 221 located within it. a shaft 230 extends, which is rotatably mounted therein. The two valve members 205 of the valves 200 and 210 are joined together via a single shaft at 231. A helical screw part 232 is formed on the input shaft 230, which meshes with a complementary driven transmission shaft at 231, with which the valve members 205 with are connected. Thus, by driving shaft 230, valves 200 and 210 will be operated simultaneously.

Valves 200 and 210 have phase positions which differ 180 ° from each other, so that when the manifold 210 is connected to the air supply, valve 200 relieves air pressure in the manifold to the exhaust system. The shaft 230 is connected to a power actuator such as a pneumatic or electric motor for simultaneously operating both valves 200 and 210. The actuator connected to the shaft 230 produces a 180 ° rotation after each actuation signal. This simultaneously turns both valves 200 and 210 through 180 °, so that on one side of the valve system the air supply is connected to the k manifold, while at the same time on the other side of the valve system the air pressure in the manifold is unload to the exhaust system. In the next operating cycle, the valves change function so that the manifold on the side where the air pressure was relieved is now received while the side of the manifold connected to the air supply is connected to the exhaust. The valve system is configured to provide a closure for the two separate air supply lines to the top and bottom die blocks. When the lower die block receives pressurized air through, for example, the valve 210 in FIG. 20, the upper die block is controlled through the valve 200 and communicates with the air exhaust system. The shaft 230 is preferably alloyed by means of a pair of bearing plates or pillow blocks 234 and 235.

Fig. 26 shows the schematic of the control system, the hydraulic system and the air pressure system. A control panel 300, containing conventional semiconductor and / or microprocessor chains, is arranged close to the container manufacturing device. A high-pressure air compressor 301 supplies air pressure to the various air-operated elements. A hydraulic pump 302 delivers a high pressure hydraulic fluid to the hydraulically driven elements.

The air compressor 301 supplies pressurized air to the thermoforming blocks 105 and 107 via a supply line 305 via a main supply line 303, which includes a main valve 304, via a supply line 305. A four-way connector 306 is included on line 305, which supplies pressurized air to air pressure regulators 307, 308 and 309. " The controller 309 supplies low pressure air for the thermoforming operation to the supply line 310, which is connected to the low pressure reservoir 114. The controller 308 supplies high pressure operating air via a high pressure line 311 to the high pressure reservoir 113.

The air compressor 301 provides an air pressure of 2 42 kg / cm or higher. The air pressure in the line 305 is preferably in the range of 28-39 kg / cm. Regulator 309 supplies low pressure air over line 310 with a pressure value in the range of 7 to 14 kg / cm. The controller 308 preferably supplies high pressure air in the pressure range of 28-39 kg / cm to the reservoir 113. The high pressure air, which is collected in the reservoir 113, is connected via a line 312 to the three-way valve system 20 210. valve system 210 directs the high pressure supply line 313 directly to a T-connector, which provides a supply to the lower die block 105.

The reservoir 114 provides a high pressure air charge over the line 314 to an electrically operated valve 315, 25 which in turn has a pneumatic connection to the three-way valve structure 200. The valve structure 200 connects the low pressure supply line 316 to a T-connector providing the supply. on the die block 107.

The air pressure regulator 307, which receives high pressure air through line 305, provides controlled air pressure across the supply line 317 to the electrically operated valve 318, which in turn supplies operating air to an air motor 320 through a line 319 at desired times. The actuator motor 320 drives a common shaft 205 between valves 200 and 210.

A second high pressure line 321 from air compressor 301 is connected to a fourth air pressure regulator 322 for supplying operating air through a line 323 to various members of the thermoforming device. The line 324 is connected to an 8203448-30 electrically operated program valve 325, which supplies operating air via a line 326 at desired times of operating air to the operating cylinder 327 of the cutting device 130. The supply line 323 is further connected to a pair of electrically operated valves 328 and 329, which provide compressed air for operating the air cylinders of the upper die block and the lower die block. The lower mold block valve 328 simultaneously supplies air to the pivot arm cylinders 330L and 330R. At the same time, the central cylinder 110L receives air pressure through the valve 328.

The top control valve 329 simultaneously supplies compressed air to the hinge arm cylinders 331L and 331R of the top die block. At the same time, air is supplied to the central cylinder 110U. This has given a method of supplying pressurized air to various air-operated elements of the thermoforming system.

The hydraulic pump 302, which can be operated by an electric motor 340 attached thereto, delivers a hydraulic fluid under pressure to a line 341. This line includes an electrically operated program valve 342, delivering a hydraulic fluid to a double acting hydraulic cylinder 343 via a first stage pressure line 344 and a reverse stage pressure line 345. The used hydraulic fluid is supplied via a line 346 to the hydraulic pump 302. The hydraulic fluid is further supplied via a line 347 to a mechanically operated valve 348 , which is served. for displacing the upper die 30 block 107. Valve 348 supplies hydraulic fluid through lines 349 and 350 to enhance the air pressure actuation of cylinders 331L and 331R. This reinforcing hydraulic pressure occurs when the die block 107 reaches the lower end of its displacement path and serves to press die die block 107 under pressure onto the block 105 immediately before the thermoforming process takes place. The used hydraulic fluid returns from the cylinders 331L and 331R through return lines (not shown) to the hydraulic pump 302.

The control panel 300 contains several 6203448: -31 signal lines, which communicate with the different controls in the air pressure system and the hydraulic system. An electrical lead 360 supplies an electrical control signal to the air actuating valve 318 to actuate the air motor 320 to the valve system 200, 210. A second signal lead 3.61 supplies an electrical signal from the operating panel to the low pressure air supply valve 315 A third signal line 362 supplies an electrical control signal to the air pressure valve 325. A signal supply line 363 provides an electrical control signal for the air pressure valve 328. A signal supply line 364 provides an actuation signal for the air valve 355 connected to the air actuator cylinder 356, which in a given embodiment is arranged to rotate the top thermoplastic container parts out of their respective mold cavities.

Air is supplied to a valve 355 via an air pressure line 354, which in turn is connected to the main air supply line 323.

A further electrical supply line 365 supplies a signal from the control panel 300 to the mechanical control valve 348 in the hydraulic system.

The electrical signal transmitted across line 365 forms the shutdown mechanism to terminate the boosting hydraulic pressure on the cylinders 331 after the thermoforming operation has been completed. A signal supply line 366 provides an electrical control signal to the air pressure valve 329 for operating the three top cylinders in the top block construction. Furthermore, a signal supply line 367 extends from the control panel to the hydraulic control valve 342 to provide two different hydraulic fluid sources to the double-acting hydraulic cylinder 343. Finally, an electrical signal is supplied to the oven via a signal supply line 368 from the control panel. 123, which provides a feedback monitor to keep the oven temperature constant during the operation of the thermoforming device.

Thus, Fig. 26 shows a typical diagram of the 4Ό air pressure supply system, the hydraulic flux supply system 8203448-32 system and the signal delivery system in the electrical control panel. The main electric power is supplied externally to various parts of the system such as the hydraulic pump motor 340, the oven 123 and the air compressor motor 301. These electric power sources are not shown in more detail in the diagram according to fig. 26, since they are easily can be applied and are only indirectly involved in the operating system.

The control panel 300 further includes a number of programmable internal timing means for supplying signals across the lines 360 ...... 368 at the correct times to provide the aforementioned pneumatic, hydraulic and electric at the correct sequence and at the correct times. operate actuated valves and controls. The construction and programming of these timing controls is assumed to be sufficiently known to those skilled in the art, so that a further explanation thereof is considered superfluous.

As shown in Figure 11, a sheet of thermoplastic material such as, for example, polyethylene terephthalate, after being placed on the feed roller 126 is fed over the feed chain belt 122. The upwardly projecting teeth 122a of the feed belt 122: puncture in the side strips of The sheet 128, whereby this sheet is driven over the rollers 121 and thus is fed to the mold construction 105, 107 (fig. 10). The chain conveyor 122 is driven in that it engages a drive roller 129, which on its shaft is provided with a drive sprocket 370 as shown in FIG. 26. The sprocket 370 is coupled via an endless drive chain 371 to a sprocket 372 as shown in Fig. 26. This sprocket 372 is mounted on a shaft that runs parallel to the shaft of the roller 129 (Fig. 11) and meshes with a rack 373 to provide a sprocket / rack construction between the double-acting cylinder 343 and the gear 372.

The hydraulic fluid over line 345 actuates cylinder 342, which drives cylinder shaft 344 and moves rack to the left. The 40 is a stepping motion relative to the sprocket 372, 8203448 -33- wherein the drive chain 372 is not moved. An electrical signal across the supply line 367 actuates the program valve 342 to reverse the hydraulic fluid to the opposite end of the cylinder 343 so that the plunger is driven to the right, thereby also retracting the rack 373 to the right in fig. 26. This causes the sprocket 372 to rotate, causing the endless chain 371 to rotate counterclockwise. This also causes the gear wheel 370 to rotate, thereby driving the roller 129 of Figure 11 and thus passing the sheet of thermoplastic material 128 through the thermoforming device. The used hydraulic fluid from the cylinder 343 is returned via the hydraulic line 346 to the storage chamber (not shown in more detail) of the hydraulic pump 302.

As the sheet 128 in FIG. 11 is advanced by the chain conveyor 122, the oven 123 receives a continuously monitored signal for providing heat in the vicinity of the sheet 128 on both sides thereof as this sheet advances toward the molding device 105, 107. When a sufficient amount of the sheet 128 has been placed between the upper die block 105 and the lower die block 107, the double-acting cylinder 343 of FIG. 26 reverses direction, stopping the movement of the chain conveyor 122 and therefore also that of the sheet 128.

At this time, control signals are issued to energize the air cylinder system 110, 331 (Figures 11 and 26) to lower the upper die block 30 107 onto the lower die block 105. When the die block 107 contacts the die block 105 it is also contacted with the actuator valve 348 by a mechanical contact switch, thereby delivering increased hydraulic fluid pressure to the cylinders 331 so that the die block 107 is further depressed on the die block 105. At the same time, an electrical signal is applied to the lower cylinders 110, 330 to provide upward pressure to the lower die block 105, thus ensuring a high-pressure seal of the die blocks 105 and 107 together 8203448-34. At this time, after advancing through the oven 123, the sheet 128 has been brought to the correct temperature range. Preferably, a temperature is chosen for this, which provides the highest melt strength to the sheet above the maximum orientation temperature. At this temperature, therefore, any stretch or formation of the sheet will not provide orientation. This is desirable since a preform can thus be provided on the lower preform dies 140.

The preforms are completed by cooling them on the dies 140 during their residence time to within the orientation temperature range. This residence time is predetermined for each type of resin used to form the sheet, and is controlled by operating the valves 200, 210 and 315.

The configuration of the preform dies 140 is chosen such that in the final forming step from pressurizing the products to their final shape (in dies 170 and 180), an optimal orientation along two axes in both radial and axial directions is achieved reached.

During the operation, the heated sheet is clamped between the die blocks 105 and 107 and enclosed by the compression grooves 145 and 266 between the upper and lower dies 180 and 140 aligned axially, respectively. Valves 315 and 200 are operated to introduce a low pressure air charge of about 11 kg / cm 2 into the top die block 107. This air is fed through air channels 179 and 185 into the top die and blows the plasticized sheet down onto the preform die 140. This pressure is maintained for the predetermined residence time from 0.10 to 1.0 sec. and the die absorbs the heat from the sheet, causing this sheet to cool to within the orientation temperature range.

Valves 315 and 200 are then closed while valve 210 is operated. This relieves pressure in the upper die 107 and brings a high pressure air charge through line 313 into the lower die block 105.

This air preferably has a pressure of about 70 kg / cm 2 8203448 -35- and flows via channels 153, 167 and 169 to the lower molds. This air then blows the flexible material sheet into the upper dies 170, 180, after which the sheet is oriented along two axes, that is, stretched in the radial and axial directions. After being contacted with the top dies, the material is further cooled below its thermoplastic temperature and then cured in the top dies.

At this time at the end of the final residence time, the die blocks are separated from each other. The threaded neck members of the containers are driven out of the dies 180, 190 by the sliding or rotary movement of the threaded member of the mold as previously described. Shortly thereafter, the rack 373 will engage the gear 372, thereby imparting translational movement to the sheet of material to cause it to move out of the region of the die blocks and into the cutting device 130. The container parts are then cut from the excess sheet material by the cutting device moving downward and then discharged or spin welded. By simultaneously rotating the gears 195 by an endless chain belt connected to the spin welding machine motor 356, the threaded parts 192 of the mold structures are turned in a direction in which the thermoplastic bottle part placed therein would be loosened. Since the holder parts are still integrally formed with the sheet material, the holder part will not rotate with the rotary movement of the mold part 192.

The mold part 192 will therefore rotate in the counter-clockwise direction of rotation when viewed from above. Since the mold part 192 is enclosed in the mold block 107, it cannot move upwardly away from the thermoplastic container part. Thus, by the rotary movement of the die part 192, the upper container portion is driven down from the threaded portion until it releases from it and falls out of the die block 107. Of course, the timing of the spinning device is such that the spinning operation does not begin until the die block 107 is lifted from the die block 105.

8203448 -36-

The separation of the die blocks 105 and 107 is effected by driving the double acting cylinders 330, 331 and 110 in the reverse direction. This takes place with the aid of electrical signals from the control panel 5 to the various air valves. control cylinder action.

To supply the high pressure air across the lower die block 105 to the thermoplastic preform material while this material is at its optimum orientation temperature ¾ 10, this material is expelled axially upwards and radially outwards in the upper mold cavities. This combined radial and axial expansion of the thermoplastic material while it is at its orientation temperature results in a balanced orientation along two axes of the finished thermoplastic container.

This is highly desirable in a thermoplastic container, since the tensile strength is thus greatly improved in both the radial and axial directions, while, moreover, it is contemplated that there is a significant improvement in the sealing properties of the material.

After the die blocks 105 and 107 are separated by the respective air charges and hydraulic displacements, the drive cylinder 343 is operated in the direction that the gear 372 rotates in the counterclockwise direction and thus drives the chain 371. This advances the chain belt 122, which in turn causes the sheet 128 to move in the thermoforming device.

By the movement of the sheet 128, a purely unformed portion of the sheet is brought into the region between the die 30 blocks 105 and 107, while the thermoformed portion of the sheet is also fed into the cutter 130 to form the holders of the separate sheet material. The separated finished containers are then removed from the cutter by conventional conveyors and passed to a spin seal for permanent joining of the lower and upper container parts. The surplus sheet material can be returned from the cutting device to a repermeter, which in turn feeds the material - to an extruder to form a new sheet.

8203448 -37-

Thus, according to the invention, there is provided an apparatus for rapidly and efficiently forming two-axis oriented products in a single-pass, continuously operating system. According to the invention, the problems of the conventional devices are overcome, which require an injection molding operation of a preform (parison) and then a thermoforming operation of this preform in a separate group of operations. According to the invention, on the other hand, there is provided an apparatus for forming a preform and immediately converting this preform into the final, two-axis oriented product. By eliminating the conventional injection molding operation step, the apparatus of the invention reduces the cost and time required to form the dual-axis product by a significant percentage. According to the invention, there are provided containers and other thermoplastic products which, when completed, have a substantially perfectly balanced two-axis orientation as measured by the diffusion values of the completed containers. By using feedback and adjustable microprocessor chains in the control panel, the device according to the invention can be operated by a single operator or at most two persons and can be adjusted during operation to achieve maximum quality. quantity and quantity of finished products. According to the invention, it has been found useful to form products from a material such as polystyrene or polyethylene terephthalate. Also, according to the invention, containers of coextruded sheet material can be formed in several layers of different resin material.

It will be clear that the invention is by no means limited to the above-described exemplary embodiments, but that other modified embodiments are possible without departing from the scope of the invention. For example, die blocks with twelve or more cavities instead of four can be used.

-claims 40 8203448

Claims (18)

1. A method of manufacturing a hi-product formed from a two-axis oriented thermoplastic resin material, which method comprises supplying a sheet of thermoplastic material, heating the sheet of thermoplastic material to a temperature above orientation temperature of the thermoplastic material, from pressing a surface area of the heated thermoplastic sheet between a first mold half and a second mold half, the first mold half of which has a preform mold surface with a configuration predetermined to provide a uniform wall thickness of the hollow product to be formed, which surface is at a temperature not higher than the orientation temperature of the thermoplastic material, the second mold half of which has a cavity corresponding to the shape of the hollow to be manufactured product from floating by means of a differential pressure of h The heated thermoplastic sheet in the first mold half against the surface, from contacting this surface of the thermoplastic sheet for a period of time, which is sufficient to bring the thermoplastic sheet to its orientation temperature, and from floating in the second mold half. the thermoplastic sheet by means of a differential pressure sufficient to align the thermoplastic sheet with the cavity in the second mold half to form a hay product, with a force sufficient to form the thermoplastic material essentially molecular orientations in both the longitudinal and lateral directions. 2. A method according to claim 1, characterized in that the thermoplastic material is heated to a temperature slightly above its orientation temperature 8203448-39-. 3. A method according to claim 2, characterized in that the thermoplastic sheet is kept in contact with the surface for a period of time / which is less than about 1 sec. 4. A method according to claim 3, characterized in that the thermoplastic sheet is kept in contact with the surface for a time period smaller than about 0.5 sec. 5. A method according to claim 4, characterized in that the thermoplastic sheet is kept in contact with the surface for a period of time between about 0.1 and 0.5 sec. 6. A method according to claim 5, characterized in that the thermoplastic sheet is kept in contact with the surface for a period of time between about 0.2 and 0.4 sec. 7. Method according to claim 1, characterized in that the thermoplastic sheet is driven against the first mold half with a pressure difference of approximately 2.8 to 24.5 kg / cm. 8. Method according to claim 1, characterized in that the thermoplastic sheets in the second mold-30 are driven by a pressure difference of about 14 to 70 kg / cm2. Method according to claim 8, characterized in that the pressure difference for driving the thermoplastic sheet into the second mold half is obtained by injecting compressed air into the first mold half between the surface and the thermoplastic sheet . 10. Process according to claim 1, characterized in that the thermoplastic material is a polyester, 8203448, t -40- a polyolefin, a polyvinyl aromatic, a nitrile-containing polymer, an acrylic polymer, a polyamide or a vinyl ester. Method according to claim 1, characterized in that the thermoplastic sheet consists of a number of layers of different polymeric materials. 12. A method according to claim 11, characterized in that the thermoplastic sheet consists of at least one layer of polyethylene terephthalate and at least one layer of ethylene vinyl alcohol. 13. A method according to claim 1, characterized in that a number of hollow products are formed simultaneously from a single thermoplastic sheet. 14. A method according to claim 13, characterized in that it further comprises separating a number of hollow products from each other. 15. Method according to claim 14, characterized in that at least SSn of the number of hollow products consists of a container top part and that at least Sen 25 of the number of hollow products consists of a suitable container bottom part. 16. A method according to claim 15, characterized in that it further comprises joining the container top parts and the container bottom part to produce a mud. 17. A method according to claim 16, characterized in that the container consists of a carbonated beverage bottle. 18. A method according to claim 16, characterized in that the manufacturing step of joining the two parts consists of welding the container parts together by means of friction welding 40. 8203448 -41- 19.1 Device for forming biaxial hollow thermoplastic products with a material sheet in a continuous operation, which device consists of an elongated horizontal bed, from an endless chain drive system along the bed. , from a heating furnace for heating at least a part of the bed, from a lower die block at one end of the bed, in which block at least one die cavity is formed, from an upper die block, which is aligned with And above the lower die block is disposed and is provided with at least one die cavity therein, which is vertically oriented with a die cavity in the lower die block, from a pressure actuator between the upper and lower die blocks for pressing the abutment with sufficient force die blocks to maintain a gas pressure of up to at least about 42 kg / cm therebetween, from a preform gas pressure system connected to a mold cavity of one of the mold blocks for injecting a gas pressure change herein in the range of from about 7 to about 14 kg / cm, from a first timing means for maintaining a preform gas pressure for a predetermined preform residence time, from a final molding gas pressure system, connected to a mold cavity of the other mold block for injecting a pressurized gas charge therein in the range of about 14 to about 70 kg / cm, from a second timer for maintaining the final molding gas pressure for a predetermined final molding residence time, from valve members with actuators thereon for controlling the preform and final molding gas pressure systems, and from adjustable controllers for controlling the valve members and residence times. 20. Device according to claim 19, characterized in that the first residence time is about 0.10 to 1.0 35 sec. and that the valve members consist of a first normally open valve and a second normally closed valve, which valves are operatively connected to each other and are operable together by a single actuator. 40 8203448 -42- 21. Device as claimed in claim 19, characterized in that it further comprises a compressed air supply system for supplying the gas pressure to the operating member and the pressure systems, from valve members 5 for controlling the air supply system, and from a adjustable valve control means for operating the valve members. 22. Device according to claim 21, characterized in that the valve control member consists of an operating panel with electronic timing means and electrical signal lines connected to the valve members. 23. Device according to claim 19, 20, 21 or 22, characterized in that it further comprises a hydraulic pressure booster between the upper and lower die block for increasing the pressing pressure thereon. 24. Device according to claim 19, 20, 21 or 22, characterized in that it further comprises gas discharge reservoirs in the gas pressure systems for supplying a volumetric air charge with a relatively constant pressure. 25. Device according to claim 19, 20, 21 or 22, characterized in that the top and bottom die blocks each contain about 2 to about 20 die cavities, each of which contains a removable die with air passage means therethrough. 26. Device according to claim 19, 20, 21 or 22, characterized in that the top and bottom die blocks each contain about 2 to about 20 die cavities, each having a removable die herein with air passage means therethrough, the number of cavities 35 in one block is equal to the number in the other block and is vertically aligned with the cavities in the other block. 27. Device according to claim 19, 20, 21 or 22, characterized in that the top and bottom die blocks each contain about 2 to about 20 die cavities, each having a removable die with air permeability therein. passage means therethrough, the cavities in one block consisting of preform cavities, the number of which is equal to the number of cavities in the other block and vertically aligned therewith, the cavity in the other block being final mold cavities divided in at least the upper container part-forming cavity and at least one lower container part / forming cavity, suitable for forming an upper and a lower container part, which can be welded by means of rotary welding. 28. Device as claimed in claim 27, characterized in that the air passage means consist of strongly porous raetal. 29. Device according to claim 19, 20, 21 or 22, characterized in that it further comprises a member for cutting thermoformed products from a thermoplastic sheet, and a rotary welding member for welding together cylindrical parts of thermoplastic products. 30. Thermoforming system for forming hollow, two-axis oriented products from a thermoplastic resin sheet material, characterized in that the system consists of a die block assembly, composed of a first die block and a second die block, which are tightly pressed together, from at least one preform gas pressure die in edn of the mold blocks, from at least one final mold gas pressure die in the other of the mold blocks, which is aligned with the preform gas pressure mold, from means for moving each other toward and away from each other the die blocks, from means for holding the die blocks together with pressures herein up to about 70 kg / cm, from a first gas pressure supply system, connected to the final molding gas pressure die to supply the die with preselected and time-controlled volume loads of pressure gas in the area from about 7 to 2 ^ about 21 kg / cm, from a second gas pressure supply system, 40 bonded with the preform gas pressure die to supply to the die 8203448 2-44 and pre-selected and time-controlled volume pressures of pressure gas in the range of about 17.5 to about 70 kg / cm. 31. The thermoforming system according to claim 30, characterized in that it further comprises means for advancing the thermoplastic resin sheet material between the die blocks in periodic incremental increments. 32. The thermoforming system according to claim 31, characterized in that said system further comprises a heater for heating the sheet material to a temperature above its orientation temperature, but below its melting point before advancing it between the die blocks. . 33. A thermoforming system according to claim 30 or 32, characterized in that it further comprises a control system with a signal delivery means and an adjustable variable time control means, which control system is suitable for controlling the movement means, the holding means, the propelling means , the heating means and the gas pressure supply systems. 34. Thermoforming system for forming biaxial-oriented hollow products from a sheet of thermoplastic resin material, characterized in that this system consists of a pair of opposed mold blocks, each of which is at least one mold cavity, one of which is mold block herein has a preform die with gas passageways therethrough, while the other die block has a final mold with gas passageways therethrough, from a low pressure gas supply source, which is connected to the final mold die through low pressure valve means and is suitable for a predetermined volume load of pressurized gas in the range of 7 up to 17½ kg / dn. from a high pressure gas supply source which is connected to the preform die via high pressure valve means and is adapted to supply a predetermined volume charge of pressure gas in the range from about 7 to about 17.5 kg / cm. carry out 8203448 '. And bending members on the opposed die blocks, from press-on members on the blocks, which are adapted to press the blocks together sufficiently to provide a seal against the internal pressure therein of at least about 42 kg / cm, from means for periodically moving the sheet of resin material between the die blocks, from means for preheating the sheet of resin material to a temperature between its orientation temperature and its liquid melting temperature before the traverse path between the die blocks, from means for providing predetermined residence times in each of the die blocks, and from means for automatically sequentially operating the low-pressure and high-pressure valves, de-opening and closing members, the pressing members and the sheet moving means organs. 8203448