Sidel, Inc.

Gerard Denis

Paul La Barre

Jean-Michel Rius

Alain Evrard

Jean-Michel Ruis

Rene Hudebine

Blow molding processes for the manufacture of polyethylene terephthalate (PET) containers are disclosed. The containers are capable of withstanding, without appreciable deformation, relatively severe thermal conditions encountered during processing by filling with a hot liquid or pasteurization of the contents of the container. A representative process includes the steps of blow molding the heated body of an amorphous PET preform comprising a body and a neck section having a body with dimensions greater than the dimensions of the final PET container to be formed; heating only the body of the intermediate container under specified conditions to rapidly shrink the body, thus forming a contracted body; heating the neck section to effect crystallization thereof; slowly cooling the neck section alone while heating of the contracted intermediate body continues; and blow molding the heated contracted body of the intermediate container in a second mold to its final shape and dimensions.

Blow molding process for the manufacture of polyethylene terephthalate

Equipment for manufacturing a polyethylene terephthalate container which is capable of withstanding, without appreciable deformation, relatively severe thermal conditions encountered during processing by filling with a hot liquid or pasteurization of the contents of the container. The equipment includes a first mold which is designed to shape the body of an intermediate container from the body of an amorphous polyethylene terephthalate preform to a size larger than the dimensions of the final container to be obtained. Second, the equipment includes a treatment station which itself includes a first heating device which first heats only the body section of the intermediate container to a temperature of about 160.degree. to about 240.degree. C. to rapidly shrink the body of the intermediate container and then heats the neck section while the contracted intermediate body continues to be heated to effect crystallization of the neck section and increase the crystallinity of the contracted intermediate container body. The treatment station then slowly cools the neck section while heating of the contracted intermediate container body continues. The heated intermediate container is placed in a second mold which has dimensions corresponding to the final size of the container to be obtained.

Equipment for the manufacture of polyethylene terephthalate containers

Equipment for manufacturing a polyethylene terephthalate container which is capable of withstanding, without appreciable deformation, relatively severe thermal conditions encountered during processing by filling with a hot liquid or pasteurization of the contents of the container. The equipment includes a first mold which is designed to shape the body of an intermediate container from the body of an amorphous polyethylene terephthalate preform to a size larger than the dimensions of the final container to be obtained. Second, the equipment includes a treatment station which itself includes a first heating device which simultaneously heats the body and neck section of the intermediate container to a temperature of about 160.degree. to about 240.degree. C. to rapidly shrink the body of the intermediate container and to effect crystallization of the neck section and increase the crystallinity of the contracted intermediate container body. The treatment station then slowly cools the neck section while heating of the contracted intermediate container body continues. The heated intermediate container is placed in a second mold which has dimensions corresponding to the final size of the container to be obtained.

A continuous-feed thermal treatment unit for the manufacture of PET containers includes, in succession, a recovery oven (25) and a crystallization oven (42) having respective heater plates (27, 44) for emitting medium-wavelength infrared radiation to heat the bodies of incoming, rotating, bidirectionally stretched, oversize containers to a temperature of 160.degree.-2400.degree.-C. The crystallization oven also includes short-wavelength infrared tubes (47) disposed along the path of the container necks, whose radiation penetrates the necks and heats support mandrels (18) inserted therein to transport the containers. The heated bodies shrink and become at least partially crystallized during their conveyance through the ovens, while the necks undergo spherulitic crystallization. The mandrels are carried at the outer ends of radial arms (15) mounted on links (12) joined by pivots (13) to form an endless conveyor chain (9) led over a portion of a drive wheel (10), during which the spacing between adjacent containers is increased to accommodate their relatively large incoming dimensions. As the conveyor chain and the containers transported thereby enter a straight run into the crystallization oven upon leaving the recovery oven, wherein they have contracted, the arms (15) return to a parallel orientation which attendantly decreases the spacing between the containers. The transported containers thus form a continuous curtain during their conveyance, which increases the thermal/energy efficiency of the treatment unit.

Thermal treatment unit for the manufacture of pet containers

Equipment for manufacturing a polyethylene terephthalate container which is capable of withstanding, without appreciable deformation, relatively severe thermal conditions encountered during processing by filling with a hot liquid or pasteurization of the contents of the container. The equipment includes a first mold which is designed to shape the body of an intermediate container from the body of an amorphous polyethylene terephthalate preform to a size larger than the dimensions of the final container to be obtained. Second, the equipment includes a treatment station which itself includes a first heating device which simultaneously heats the body and neck section of the intermediate container to a temperature of about 160.degree. to about 240.degree. C. to rapidly shrink the body of the intermediate container and to effect crystallization of the neck section and increase the crystallinity of the contracted intermediate container body. The treatment station then slowly cools the contracted intermediate container body and the neck section, whereafter a second heating device heats the contracted intermediate container prior to placing it in a second mold. The second mold has dimensions corresponding to the final size of the container to be obtained.

Equipment for the manufacture of polyethylene terephtalate containers

A core 6 is disposed inside of and spaced from a hollow plastic preform 1 subjected to external infrared radiation 4 including a first wavelength B.sub.1 that is absorbed by and heats the plastic, and a second wavelength B.sub.2 that propagates through the wall 2 of the preform. The propagated radiation 12 is converted into the first wavelength by the surface 7 of the core, and reemitted at 13 back towards the preform to heat its internal surface 8 to a higher temperature than its external surface 10. The preform may be axially rotated with the core stationary to implement uniform angular heating. Alternatively, the core may be irregularly configured and/or surface treated, with both the core and preform rotated in synchronism.

Method and apparatus for infrared heating of plastic preforms

A process for the manufacture of a polyethylene terephthalate (PET) container capable of withstanding, without appreciable deformation, relatively severe thermal conditions encountered during processing by filling with a hot liquid or pasteurization of the contents of the container. The process inlcudes the following steps, on an amorphous PET preform which includes a body and a neck section which already possesses the final shape and dimensions of the PET container to be formed, heating only the body, exclusive of the neck section, of the PET preform to a temperature at least equal to the PET-softening temperature; in a mold, blow molding the heated preform body to form an intermediate container whose body has dimensions greater, by about 20% with respect to height and by 0 to about 30% transversely, than the dimensions of the PET container to be formed, while cooling the mold walls holding the intermediate container to a temperature of about 5.degree. to about 40.degree. C.; heating the body of the intermediate container to a temperature of about 160.degree. to about 240.degree. C. for a period of about 1 to about 5 minutes to obtain an intermediate container with contracted body, while heating the neck section during part of or the entire body heating time under temperature and time conditions sufficient to allow crystallization of the PET neck section alone; slowly cooling the neck section; and blow molding the heated contracted body of the intermediate container obtained to its final shape and dimensions for a period of about 2 to about 6 seconds.

A process for the manufacture of a polyethylene terephthalate (PET) container from a hollow amorphous PET preform which includes an open end and a closed end, the open end forming a neck section having dimensions already conformed to its final size and shape, the container being able to withstand relatively severe thermal conditions encountered when the container is filled with a hot liquid, without appreciable deformation, including the steps of: a) rapidly heating only the body of the PET preform, exclusive of the neck section, to a temperature at which subsequent longitudinal and transverse stretching cause no stresses in the PET; b) transferring the hot preform from step (a) to a mold whose walls are maintained at a temperature lower than the temperature of the hot preform body; c) longitudinally stretching the preform body while simultaneously transversely expanding it by blow-molding using a pressurized fluid so as to mold the preform body to the shape of the mold cavity; d) rapidly evacuating the pressurized fluid from the molded container of step (c); and e) removing the container from the mold.

Process for the manufacture of PET containers designed to be filled with

An apparatus for the heat treatment of the necks 1 of performs 2 includes a rotatable mandrel 3, which is inserted in and engaged with the neck of the preform to rotate it, a fixed protective skirt 4, and a heater 5 situated at the level of the neck. A sliding weight 28 is applied to the upper end of the neck during the heat treatment.

Apparatus for heat treatment of preform necks

A heat resistant container is made from a PET preform by crystallizing its neck (10), heating just its body to the softening temperature of PET, blow molding an intermediate container (21) in a cooled mold (5.degree. to 40.degree. C.) with a larger volume than that of the final container to be obtained, heating the intermediate container to 180.degree.-220.degree. C. for 1 to 15 min, and then molding it a second time to its final dimensions at a temperature of 80.degree.-100.degree. C. for 2 to 6 sec.

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Turretot, France

Gerard Denis