Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/42—Component parts, details or accessories; Auxiliary operations
  • B29C49/64—Heating or cooling preforms, parisons or blown articles
  • B29C49/6409—Thermal conditioning of preforms
  • B29C49/6463—Thermal conditioning of preforms by contact heating or cooling, e.g. mandrels or cores specially adapted for heating or cooling preforms
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/02—Combined blow-moulding and manufacture of the preform or the parison
  • B29C49/06—Injection blow-moulding
  • B29C49/061—Injection blow-moulding with parison holding means displaceable between injection and blow stations
  • B29C49/062—Injection blow-moulding with parison holding means displaceable between injection and blow stations following an arcuate path, e.g. rotary or oscillating-type
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/02—Combined blow-moulding and manufacture of the preform or the parison
  • B29C2049/023—Combined blow-moulding and manufacture of the preform or the parison using inherent heat of the preform, i.e. 1 step blow moulding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C2949/00—Indexing scheme relating to blow-moulding
  • B29C2949/07—Preforms or parisons characterised by their configuration
  • B29C2949/0715—Preforms or parisons characterised by their configuration the preform having one end closed
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
  • B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
  • B29C35/04—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould using liquids, gas or steam
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/02—Combined blow-moulding and manufacture of the preform or the parison
  • B29C49/06—Injection blow-moulding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/08—Biaxial stretching during blow-moulding
  • B29C49/10—Biaxial stretching during blow-moulding using mechanical means for prestretching
  • B29C49/12—Stretching rods
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/08—Biaxial stretching during blow-moulding
  • B29C49/10—Biaxial stretching during blow-moulding using mechanical means for prestretching
  • B29C49/12—Stretching rods
  • B29C49/1202—Means for fixing the stretching rod to the driving means, e.g. clamping means or bayonet connections
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2069/00—Use of PC, i.e. polycarbonates or derivatives thereof, as moulding material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2669/00—Use of PC, i.e. polycarbonates or derivatives thereof for preformed parts, e.g. for inserts

Definitions

• the invention relates to a method for manufacturing plastic containers, suitable in particular for the manufacture of polycarbonate bottles, wherein first a preform is formed in an injection molding station; then, the preform is inflated in a blowing station to form a container having the ultimately desired form; and finally, the container is removed in an ejection station.
• the invention also relates to an apparatus for using the method.
• an injection molding apparatus having a horizontal machine bed, a frameplate which is mounted above the machine bed and which is stationary or can be moved up and down, and a carousel plate mounted under the frameplate and capable of rotating about a central axis .
• the machine bed carries a half of an injection mold having one or more mold cavities, a blowing mold and an ejection station. Opposite this half of the injection mold, the frameplate is provided with opening via which one or more cores can be introduced into the mold cavity (cavities) .
• the frameplate further carries, at the location of the blowing station, means for stretching and inflating the preforms.
• a conditioning station is further present between the injection molding station and the blowing station, where the preforms to be inflated are in thermal respect brought into a suitable condition for stretching and inflating.
• the carousel plate has its bottom side provided, at positions corresponding to each station, with one or more neckrings capable of retaining the preforms formed in the injection molding station after the cores have been drawn from the mold cavities.
• the preforms produced are suspended in the neckrings .
• the carousel plate is subsequently rotated, the preforms are moved via the conditioning station to the blowing station, and then, the containers obtained, still suspending from the neckrings, are passed to the ejection station, where the neckrings are opened.
• PET bottles A drawback of PET bottles is that they cannot be cleaned at a sufficiently high temperature in order that they can for instance be used as refillable bottle for milk. At temperatures of 70°C and higher, there is the danger of a PET bottle shrinking. This drawback does not exist when a different material is used, such as polycarbonate. Bottles of polycarbonate can be cleaned at high temperature and are therefore suitable for use as, for instance, refillable milk bottle.
• the object of the invention is to overcome the problems outlined and generally to provide a method and apparatus that are suitable for manufacturing containers suitable for cleaning at high temperature, such as for instance polycarbonate bottles.
• a method of the above-described type is characterized in that each preform suspending in a neckring and internally supported by a heated core extending into the preform from above, is conveyed from the injection molding station to the blowing station, and that the core is then moved along with the inflated container to the ejection station and is then moved to an injection molding station again.
• an apparatus of the above- described type is characterized in that the core moves along with the carousel plate and the associated neckring in order to support the preform during the movement from the injection molding station to the blowing station.
• FIG. 1 and Fig. 2 schematically show, in top plan view and in side elevational view, an example of a known apparatus for manufacturing plastic containers;
• FIG. 3 and Fig. 4 illustrate in a similar manner an example of a method and apparatus according to the invention.
• Fig. 5 schematically shows an example of a blowing station of an apparatus according to the invention.
• Figs. 1 and 2 schematically illustrate the operation of a known apparatus for manufacturing plastic containers according to the blowing-mold principle.
• the known apparatus has been designed for producing PET bottles and is of a type that is for instance marketed by Nissei ASB Machine Co. Ltd.
• the known machine comprises a stationary machine bed 1 and a frameplate 2 mounted above the machine bed, which frameplate, depending on the type of molds used, is fixedly mounted or is movable up and down.
• the machine bed carries, distributed along its circumference, an injection mold part 3 having one or more mold cavities, a conditioning device 4, and a blowing mold part 5, which form part of an injection station 6, a conditioning station 7 and a blowing station 8.
• the frameplate need not be movable up and down.
• the frameplate 2 and/or the parts 3 and /or 4 and/or 5 should be movable up and down for being able to convey the containers from one station to the other.
• these stations are in each case positioned at an angular distance of 90° relative to each other, as shown in Fig. 2. Further, at 90° beyond the blowing station 8, an ejection station 9 is positioned.
• a rotating carousel plate 10 carrying one or more neckrings 11, 12, 13 at positions corresponding to the stations.
• one or more cores 14 located above the frameplate at the location of the injection station 6 are one or more cores 14 that can be lowered through the corresponding neckrings 11 into the injection mold part 3 to form, during the injection phase, one or more preforms. After a preform has been obtained in this manner, the mold formed by the mold part 3 and the core 14 opens in that either the mold part 3 opens or moves downwards, or the frameplate 2 and the core 14 move upwards.
• the core 14 moves upwards relative to the frameplate, so that the preform just formed is freely suspending from the neckring 11 and the carousel plate is free to rotate through 90° in the direction of the arrow 15.
• the just formed preform is thus moved to the conditioning station for being prepared for the blowing treatment in the blowing station.
• at least one new preform is formed in the injection station.
• the carousel plate rotates through 90° again, so that the conditioned preform reaches the blowing station 8.
• the preform is received in a blowing mold and inflated to obtain the desired shape.
• the carousel plate rotates through 90° again, so that the ready container reaches the ejection station 9.
• a just conditioned preform reaches the blowing station 8 and a just formed preform reaches the conditioning station 7.
• the preform is suspended from a neckring 11.
• the preform in preparation of the inflation of the preform, the preform is. first stretched by means of a stretching pin which is inserted through the neckring into the preform and pushes the bottom of the preform away in a direction away from the neckring.
• each neckring 11, 12, 13 is now provided with a core 20, 21, 22 rotating along with the carousel plate.
• the hot preforms are supported and retained by a neckring and a core.
• This technique enables displacement of the preforms in weaker condition.
• the preforms can be warmer than in the case of the known technique. This in turn enables for instance processing polycarbonate preforms at a suitable high temperature and/or conveying the preforms more rapidly after the injection phase.
• the stabilizing effect of the cores moving along can further be enhanced by rendering the cores and, accordingly, the preforms longer than is conventional.
• PET is used as starting material
• it is necessary to stretch a preform in the longitudinal direction before inflating the preform because only after the stretching operation the desired molecular structure with the associated mechanical strength is formed.
• this effect does not arise with polycarbonate, and that a polycarbonate preform need not be stretched in the longitudinal direction, or only to a slight degree.
• the stretching treatment results in a length increase to the order of 50%.
• cores are used whose lengths differ from that of the final product by some centimeters only.
• a length increase to the order of for instance about 15% takes place.
• the core and, accordingly, the preform could even have a length which substantially corresponds to that of the final product.
• cores are used that have a heated shell and an air duct which is closed by a central pin during the injection phase and the conditioning phase.
• the air duct is opened, allowing the preform to be inflated into the eventual shape, as will be further described hereinbelow.
• Fig. 5 schematically shows an example of a core 20 according to the invention, located in the blowing station 8.
• the core has a heated shell 30, which in this example is heated by hot oil circulating via a duct 31,32.
• the preform to be inflated is indicated at 33.
• the bore is slightly larger than the pin, so that an annular air duct 37 is present around the pin, which duct is closed by the plug 36 during the injection phase.
• the pin may also have an internal air duct.
• the pin 35 is pushed through a slight or larger distance, depending on the material of the container, beyond the end of the core into the blowing cavity 38.
• the pin In the case of a PET preform, the pin is moved down to the bottom of the blowing cavity, so that the desired stretching treatment takes place. Also, via the air duct, air is blown into the preform. This is possible because the conical plug 36 no longer closes off as soon as the pin has been slightly displaced.
• the procedure is preferably as follows. First, the pin is slid out of the core through a slight distance, for instance 0.5-1 mm. As a result, the closing member 36 opens, permitting air to be blown into the preform. The air supply is continued, involving the wall of the preform being first inflated around the free end of the core, to form a kind of balloon. When the balloon lies against the bottom of the blowing cavity, the pin 35 is pushed down further to fix the balloon in the blowing cavity. Next, the preform is further inflated until the end product having the shape of the blowing cavity has been obtained. After that, the blowing mold opens and the carousel plate rotates further through 90°, so that in the ejection station, the end product can be removed from the core and out of the neckring.
• the operation of the pin 35 takes place by means of a pusher pin 40, which is located in a frame 41 mounted above the blowing station and can be operated by a cylinder 42.
• the pusher pin 40 can be temporarily coupled to the central pin located in the core in one of the manners known therefor. In the example shown, a snap connection is used, as is also used for exchangeable hand tools.
• the pusher pin has a constriction 43 adjacent its lower end, which constriction can cooperate with balls 44 or the like around a receiving cavity 45 and a coupling member 46 of the central pin 35.
• Other coupling methods for instance by means of a bayonet closure or the like, are possible.
• the cores are heated by hot oil.
• the oil should be fed via a tube or hose having a central universal joint, as shown in Fig. 3 at 50, and conduits 51-54 that rotate along.
• a tube or hose having a central universal joint as shown in Fig. 3 at 50, and conduits 51-54 that rotate along.
• For driving the carousel plate use can then be made of a hollow shaft or, as shown in Fig. 3, a gear ring 55 driven by a drive wheel 56 of a motor, or an eccentric drive mechanism.
• the cores may also be electrically heatable. Such modifications are understood to fall within the framework of the invention.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=19763156

Family Applications (1)

Country Status (3)

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Family Cites Families (6)

• 1996
  • 1996-07-05 NL NL1003525A patent/NL1003525C2/nl not_active IP Right Cessation
• 1997
  • 1997-07-07 EP EP97929590A patent/EP0958123A1/en not_active Withdrawn
  • 1997-07-07 WO PCT/NL1997/000393 patent/WO1998001284A1/en not_active Application Discontinuation

Non-Patent Citations (1)

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