US20100237528A1 - Method for making vessels for improving the mechanical strength thereof - Google Patents

Method for making vessels for improving the mechanical strength thereof Download PDF

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Publication number
US20100237528A1
US20100237528A1 US12/663,442 US66344208A US2010237528A1 US 20100237528 A1 US20100237528 A1 US 20100237528A1 US 66344208 A US66344208 A US 66344208A US 2010237528 A1 US2010237528 A1 US 2010237528A1
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container
gaseous mixture
ignition
process according
course
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Mikaël Derrien
Pierrick Protais
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Sidel Participations SAS
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    • 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
    • B29C49/46—Component parts, details or accessories; Auxiliary operations characterised by using particular environment or blow fluids other than air
    • 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
    • B29C49/46—Component parts, details or accessories; Auxiliary operations characterised by using particular environment or blow fluids other than air
    • B29C2049/4602—Blowing fluids
    • B29C2049/4647—Blowing fluids created by an explosive gas mixture
    • 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
    • B29C49/78—Measuring, controlling or regulating
    • B29C49/783—Measuring, controlling or regulating blowing pressure
    • B29C2049/7831—Measuring, controlling or regulating blowing pressure characterised by pressure values or ranges
    • 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
    • B29C49/78—Measuring, controlling or regulating
    • B29C49/783—Measuring, controlling or regulating blowing pressure
    • B29C2049/7832—Blowing with two or more pressure levels
    • 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
    • B29C49/78—Measuring, controlling or regulating
    • B29C49/786—Temperature
    • B29C2049/7864—Temperature of the mould
    • B29C2049/78645—Temperature of the mould characterised by temperature values or ranges
    • 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
    • B29C49/78—Measuring, controlling or regulating
    • B29C49/786—Temperature
    • B29C2049/7868—Temperature of the articles
    • 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
    • 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
    • B29C49/16—Biaxial stretching during blow-moulding using pressure difference for pre-stretching, e.g. pre-blowing
    • 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
    • B29C49/6604—Thermal conditioning of the blown article
    • B29C49/6605—Heating the article, e.g. for hot fill
    • 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
    • B29C49/78—Measuring, controlling or regulating
    • B29C49/783—Measuring, controlling or regulating blowing pressure
    • 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
    • B29K2067/00—Use of polyesters or derivatives thereof, as moulding material

Definitions

  • the invention concerns the manufacture of containers, by blowing or stretch-blowing from polymer blanks.
  • blank will not only cover the notion of a preform, but also that of an intermediate container, that is to say an object having undergone a first blowing (which can be free) and intended to undergo a second to form the final container.
  • polyesters are saturated polyesters and particularly PET (poly(-ethylene terephthalate)).
  • stretch-blowing of containers consists of taking a polymer blank that has been pre-heated, introducing this blank into a mold with the shape of the end container to be formed, then stretching the blank by means of stretch rod (also called a cane) and blowing pressurized gas into it (generally air) to pin the material flat against the wall of the mold.
  • stretch rod also called a cane
  • pressurized gas generally air
  • the invention is certainly not limited to the PET alone; however, given that this material is, at present, that most currently used for the stretch-blowing of containers, it would appear to be appropriate to study this example carefully.
  • PET is a polyester obtained by polycondensation from terephtalic acid and from ethylene glycol. Its structure can be amorphous or partially crystalline (without exceeding 50% however). The possibility of going from one phase to another depends largely on the temperature: below its vitreous transition (T g ⁇ 80° C.), the micromolecular chains are quite mobile and the material is solid, with a congealed ((solidified)) microstructure; above the fusion temperature T f (about 270° C.), the bonds between the chains are destroyed and the material is liquid. Between these two temperatures, the chains are mobile and their conformation can change (See [2]).
  • the PET chemical formula (See [1]) is as follows:
  • the crystallization of polymer occurs between the vitreous transition temperature T g and the fusion temperature T f . If the polymer is subjected to a deformation or a flowing, the kinetic of crystallization is accelerated. It is important to note that the crystalline texture obtained in this case is complex and anisotropic (See. [3]).
  • the energy contribution necessary to modify the structure of the macromolecular chains can be thermal (which is then referred to as natural or static crystallization), or mechanical, by permanent deformation of the material. This energy contribution by deformation exhibits the following advantages, among others:
  • the PET exhibit numerous qualities: very good mechanical properties (high rigidity, good resistance to traction and to tearing), good optical properties and barrier properties to CO 2 . (See [2])
  • the mechanical properties of PET are essentially a function of the crystalline texture, the crystalline volumic fraction and the molecular dimension and orientation. It is known that these parameters are particularly affected by the thermal history of the material (See.[4]).
  • Stretch-blowing causes a bi-orientation of the polymer, that is, on the one hand, an axial orientation of the macromolecules at the time of the stretching by means of a stretch rod and, on the other hand, a radial orientation of the macromolecules at the time of the blowing.
  • the stretching of the PET causes a warped or trans type change of conformation of the molecular chains, leading to a partial crystallization of the polymer.
  • the benzenic cores tend to orient in a parallel plane to the main directions of the stretching.
  • the PET does not crystallize 100%; the maximum rate noted being about 50%.
  • the containers manufactured within the industry, and particularly bottles, generally exhibit a rate close to 35%. (See [2]).
  • the rate of crystallinity can be increased (up to 40% and, some assert, even more than that (See [6])).
  • Densimetry is based on the determination of the density of the material: when the material crystallizes, its density increases due to the compacter organization of the chains in the crystalline phase. Assuming that the specific volumes of the two phases follow a mixture law, one can then calculate the crystallinity rate by the following relationship:
  • the density d of the sample is measured by successive weighings in the air and in water.
  • the density d a 1,333 g/cm 3 of the amorphous phase is a relatively well-established value.
  • the density d c of the crystalline phase varies between 1.423 et 1.433 g/cm 3 for an oriented PET having undergone a tempering between 60° C. and 100° C.
  • the generally permissible value is 1.455 g/cm 3 .
  • the DSC analysis itself consists of establishing a thermogram for the available polymer sample. Traditionally, this thermogram was traced by implementing a heating of the material at a speed of 10° C./min.
  • T f 250° C.
  • the calculation of the initial crystallinity rate can be done by comparing the enthalpy difference (area under the peaks) between fusion and crystallization, that is noted ⁇ H, with the fusion enthalpy H ref of a PET assumed to be perfectly crystalline, the value of which is generally chosen at around 100 J.g ⁇ 1 .
  • the crystallinity rate is given by the following equation:
  • Increased crystallinity has customarily been obtained by a process known as heat setting, which consists, at the end of the blowing, of keeping the formed container against the wall of the mold, which is heated to a preset temperature that can range up to 250° C.
  • the container is thus kept pinned flat against the wall of the mold for several seconds.
  • the containers having undergone heat setting to make them resistant to deformation at the time of a hot-filling are, in current manufacturing language, called HR (heat resistant).
  • [6] proposes to circulate in the container, at the end of the blowing, a gas (of air) at a so-called high temperature between 200° C. and 400° C., so as to bring the inside wall of the container to a temperature of at least 120° C. in order to increase its crystallinity. It presumed in this document that the total duration of the manufacturing of the container can be less than 6 sec, while the crystallinity rate obtained varies from 34.4% to 46.7%. (It should be noted that it concerns average container crystallinity rates, measured by a densimetric method akin to that presented above.) According to [6], a crystallinity rate greater than 30% must be considered to be characteristic of a high crystallinity.
  • the invention seeks to propose an alternative solution for the manufacturing of polymer containers, which specifically makes it possible to obtain good performance when they are hot filled.
  • the invention proposes, according to a first aspect, a manufacturing process for a container in a mold having a cavity defining the final form of the container, from a polymer blank heated beforehand; this process comprises the following operations:
  • the container obtained by this process exhibits, with hot filling, performances at least equivalent to those of the classical processes utilizing heat setting of the container. Under certain operating conditions the performances are even better; the shrinkage of the container being very low (less than 1%, on average).
  • the process includes:
  • the process can include a stabilization operation, during which the residual gas deriving from the ignition is maintained in the container.
  • a sweeping operation is provided prior to the degassing operation during which air is circulated in the container.
  • the process comprises:
  • the process comprises:
  • the mold is preferably heated to a temperature greater than or equal to 100° C. This temperature is about 130° C. according to the method of execution. As a variant, this temperature is about 160° C. environ.
  • the explosive gaseous mixture can comprise air and hydrogen, for example with a volumetric proportion of hydrogen of about 6%, to obtain a deflagration upon ignition.
  • the pre-blowing pressure is greater than or equal to 10 bars, according to the method of execution.
  • the blowing pressure is, itself, preferably greater than or equal to 30 bars.
  • the invention proposes a machine for manufacturing containers from polymer blanks heated in advance, comprising:
  • the machine comprises a nozzle suitable for communicating with the inside of the container and for introducing gas into it, the means of ignition comprising a spark plug leading into a nozzle or, when the machine includes a stretch rod, within it.
  • FIG. 1 is a differential calorimetric analysis (DSC) thermogram illustrating the thermal capacity variations of an initially amorphous PET;
  • FIG. 2 is a schematic view of a cross-section elevation view showing a machine for manufacturing containers by stretch-blowing;
  • FIGS. 3A to 3F are schematic cross-section elevation views showing different successive stages of a manufacturing process by stretch-blowing of containers, according to a first example of execution;
  • FIG. 4A is a graph illustrating the development over time of the pressure prevailing in the container at the time of its stretch-blowing in accordance with the process illustrated in FIGS. 3A to 3F ;
  • FIG. 4B is a chronogram illustrating the opening and closing of the electromagnetic valves as well as the lighting operation within the machine illustrated on FIG. 2 , for the implementation of the process illustrated in FIGS. 3A to 3F and in FIG. 4A ;
  • FIGS. 5A to 5H are schematic cross-section elevation views showing different successive stages of a manufacturing process by stretch-blowing of containers, according to a second example of execution;
  • FIG. 6A is a graph illustrating the development over time of the pressure prevailing in the container at the time of its stretch-blowing in accordance with the process illustrated in FIGS. 5A to 5H ;
  • FIG. 6B is a chronogram illustrating the opening and closing of the electromagnetic valves as well as the lighting operation within the machine illustrated in FIG. 2 , for the implementation of the process illustrated in FIGS. 5A to 5H and in FIG. 6A ;
  • FIGS. 7A to 7L are schematic cross-section elevation views showing different successive stages of a manufacturing process by stretch-blowing of containers, according to a third example of execution;
  • FIG. 8A is a graph illustrating the development over time of the pressure prevailing in the container at the time of its stretch-blowing in accordance with the process illustrated in FIGS. 7A to 7L ;
  • FIG. 8B is a chronogram illustrating the opening and closing of the electromagnetic valves as well as the lighting operation within the machine illustrated on FIG. 2 , for the implementation of the process illustrated in FIGS. 7A to 7L and in FIG. 8A ;
  • FIGS. 9A to 9K are schematic cross-section elevation views showing different successive stages of a manufacturing process by stretch-blowing of containers, according to a fourth example of execution;
  • FIG. 10A is a graph illustrating the development over time of the pressure prevailing in the container at the time of its stretch-blowing in accordance with the process illustrated in FIGS. 9A to 9K ;
  • FIG. 10B is a chronogram illustrating the opening and closing of the electromagnetic valves as well as the lighting operation within the machine illustrated in FIG. 2 , for the implementation of the process illustrated in FIGS. 9A to 9K and on FIG. 10A ;
  • FIGS. 11A to 11F are schematic cross-section elevation views showing different successive stages of a manufacturing process by stretch-blowing of containers, according to a fifth example of execution;
  • FIG. 12A is a graph illustrating the development over time of the pressure prevailing in the container at the time of its stretch-blowing in accordance with the process illustrated in FIGS. 11A to 11F ;
  • FIG. 12B is a chronogram illustrating the opening and closing of the electromagnetic valves of a machine implementing the process illustrated in FIG. 12A ;
  • FIG. 13 is a top view showing a typical example of a container obtained by a manufacturing process according to any one of the examples illustrated on the preceding figures;
  • FIG. 14 is an enlarged scale sectional view of a detail of the body of the container of FIG. 13 , taken in the inset XIV;
  • FIG. 15 is a thermogram of differential calorimetric analysis (DSC) illustrating the variations of the mass thermal capacity of a container manufactured according to a manufacturing process according to one of the examples illustrated in the preceding figures, for five successive sections of the wall of the container; and
  • FIG. 16 is a thermogram similar to that of FIG. 14 , for a container manufactured according to a manufacturing process according to another of the examples illustrated in the preceding figures.
  • FIG. 2 partially illustrates a machine 1 for manufacturing containers 2 by stretch-blowing from polymer blanks 3 .
  • the blanks 3 are the preforms: this term is used for purposes of consistency.
  • Machine 1 comprises a plurality of molding units 4 , mounted on a carousel (not shown), each comprising one mold 5 (as illustrated in FIG. 2 ).
  • This mold 5 made of steel or aluminum alloy, comprises two die halves 6 and a mold base 7 that together define an internal cavity 8 , intended to receive a preform 3 previously heated to a temperature greater than the vitreous transition temperature (Tg) of the matter comprising the preform 3 , the shape of which corresponds to the final desired shape of the container 2 manufactured from this preform 3 .
  • container 2 (as illustrated in FIG. 13 ) generally comprises a neck 9 , a body 10 and a bottom 11 .
  • the molding unit 4 comprises:
  • the reactive gases can be hydrogen (H 2 ), methane (CH 4 ), propane (C 3 H 8 ) or acetylene (C 2 H 2 ).
  • Hydrogen is preferred due to the non-polluting character of its oxidation reaction (2H 2 +O 2 ⁇ 2H 2 O), the product of which is pure water. Hydrogen can either be produced on demand, directly upstream of the machine 1 (for example by electrolysis of the water), or stored in containers from which it is drawn for the needs of the process.
  • the conduits 20 , 24 , 28 , 32 can be established at least partially in the casing 15 , as is illustrated in FIG. 2 .
  • the electromagnetic valves EV 1 , EV 2 , EV 3 , EV 4 they are connected electrically to a control unit 34 that controls the opening and closing of them (duly taking into account the response time of the electromagnetic valves).
  • These electromagnetic valves EV 1 , EV 2 , EV 3 , EV 4 can be arranged at a distance from the casing 15 or, integrated within it for greater compactness.
  • a person skilled in the art could refer to patent application FR 2 872 082 (Sidel) or to the equivalent international patent application WO 2006/008380.
  • the molding unit 4 is in addition equipped with a device for its own ignition 35 , at a pre-set given instant and actuated by the control unit 34 , to produce within the nozzle 16 (or of the container 2 ) a spark for igniting the air and reactive gas mixture in the container 2 .
  • this ignition device 35 comprises a spark plug 36 having a center electrode 37 and an earth electrode 38 both leading into the nozzle 16 (that communicates with the inside of the container 2 )—or, as a variant, in the rod 12 —and between which, upon actuation by control unit 34 , an electrical arc can be produced, causing the ignition of the mixture.
  • molding unit 4 is in addition equipped with a circuit 39 for heating mold 5 , comprising a pressurized coolant source 40 (by oil or water, for example) and conduits 41 arranged in the thickness of the mold 5 (half dies 6 and bottom 7 included), in which the coolant fluid coming from source 40 circulates to keep mold 5 at a temperature above the ambient temperature (20° C.).
  • a pressurized coolant source 40 by oil or water, for example
  • conduits 41 arranged in the thickness of the mold 5 (half dies 6 and bottom 7 included)
  • the coolant fluid coming from source 40 circulates to keep mold 5 at a temperature above the ambient temperature (20° C.).
  • the temperature of the mold is regulated at an average value between 20° C. and 160° C. (measured on the inside wall of mold 5 ), depending on the applications—examples of temperatures are provided here following.
  • DSC is used to measure the crystallinity of a container 2 obtained by the corresponding process. More precisely, the crystallinity of body 10 of container 2 is measured, at least on the side of an inside wall 42 and of an outside wall 43 .
  • a sample is taken in the body 10 and is cut (by microtomic cutting, for example) into serial segments at its thickness, the respective crystallinity of which is then measured.
  • the sample is cut into five approximately equal segments. For example, for a container 2 , the thickness of which is approximately 360 ⁇ m, each cut segment exhibits a thickness of 50 ⁇ m (the cutting blade forming, with each pass between two successive segments, shavings of a thickness of approximately 25 ⁇ m).
  • A, B, C, D and E show the five successive segments of material, from the insider of container 2 .
  • a differential microcalorimeter with power compensation is used.
  • This microcalorimeter includes two ovens under a neutral atmosphere (generally in nitrogen).
  • a reference generally an empty cup
  • the sample on which the DSC measurements are to be made is placed into the second.
  • Each oven is equipped with two platinum resistances, one of which serves for the heating and the other for measuring the temperature.
  • the exchanged heat fluxes are measured, on the one hand between the reference and the outside medium, and on the other hand between the sample and the outside medium as the temperatures is increased at a constant heating velocity from the ambient temperature (about 20° C.) up to a temperature greater than the known fusion temperature of the studied material (in this case, for the PET it is heated up to about 300° C., it being assumed that the material fuses at approximately 250° C.).
  • m is the mass of the sample in grams
  • heating velocity q is introduced, kept constant at the time of the measurement (and in the selected case equal to 10 K ⁇ 1 ), defined by the relationship
  • thermogram Such a thermogram is shown in FIG. 1 for a sample of the PET of the manufacturer EASTMANN mentioned in the introduction.
  • thermogram makes it possible to differentiate the exothermic phenomena (oriented downwards) from the endothermic phenomena (oriented upwards).
  • a first exothermic peak in this case around 135° C.
  • an endothermic peak in this case around 250° C.
  • the rate of crystallinity of the initial material can be calculated from the thermogram, from the difference ⁇ H of the enthalpies exchanged during the fusion phenomena on the one hand, and the crystallization on the other.
  • the fusion enthalpy ⁇ H f is defined by the area under the fusion peak:
  • ⁇ ⁇ ⁇ H f ⁇ pic ⁇ ⁇ fusion ⁇ C p ⁇ ( T ) ⁇ ⁇ T
  • the crystallization enthalpy ⁇ H c is itself defined by the area under the crystallization peak:
  • H ref is the enthalpy of fusion of a presumed completely crystalline sample.
  • a value of 140 J.g ⁇ 1 is selected, which corresponds to the most value most commonly used in plastic materials laboratories.
  • mold 5 is heated such that such that it exhibits on the side of its inside wall a temperature of approximately 160° C.
  • the material of the preform 3 is a PET.
  • the reactive gas is hydrogen (H 2 ).
  • the air/hydrogen gaseous mixture is made while maintaining a hydrogen proportion in volume between 4% and 18%, preferably 6%.
  • the process comprises a first operation, known as pre-blowing, consisting of stretching preform 3 by sliding rod 12 , and simultaneously opening the electromagnetic valves EV 1 and EV 2 to introduce into preform 3 an air and reactive gas mixture at a pressure between approximately 5 and 20 bars ( FIGS. 3A to 3C , lines 1 and 2 in FIG. 4B ).
  • This first operation of a predetermined durational ⁇ 1 ends by the closing of the electromagnetic valves EV 1 and EV 2 after rod 12 has ended its travel having reached the bottom of mold 7 , and the threshold for the plastic outflow of the material has been exceeded (which is indicated on the pressure curve by a first pressure peak, at approximately 8 to 10 bars).
  • a second operation consists of igniting the gaseous mixture by ignition of a spark plug 36 ( FIG. 3D , line 3 in FIG. 4B ).
  • a spark plug 36 FIG. 3D , line 3 in FIG. 4B .
  • an explosion occurs in container 2 that is being formed, which is accompanied by a sudden increase of the temperature (which reaches hundreds of degrees Celsius) and of the pressure (which exceeds 40 bars—on the curve of FIG. 4A ; the corresponding peak pressure is clipped due to reasons of scale).
  • the duration of the ⁇ 2 of the ignition of the mixture is extremely brief (less than 25 ms), but the increased pressure that accompanies it is sufficient to pin the substance flat against the wall of the mold, thus forming container 2 .
  • a third operation consists of maintaining in container 2 a residual gas (essentially a mixture of water vapor coming from the combustion of hydrogen, with possible traces of NO x ), for a predetermined duration ⁇ 3 (between 1000 and 1500 ms) while keeping all the electromagnetic valves EV 1 , EV 2 , EV 3 , EV 4 closed, so as to permit the reduction of the temperature and the pressure in container 2 ( FIG. 3E ).
  • a residual gas essentially a mixture of water vapor coming from the combustion of hydrogen, with possible traces of NO x
  • a fourth operation consists of degassing container 2 , by closing third electromagnetic valve EV 3 ( FIG. 4B , line 4 ) and leaving fourth electromagnetic valve EV 4 for a preset duration ⁇ 4 (between 100 and 500 ms), to allow the air to escape ( FIG. 3F ) until the pressure prevailing inside container 2 has about attained the atmospheric pressure ( FIG. 4B , line 5 ).
  • the fourth electromagnetic valve EV 4 is closed, the mold 5 , opened, and container 2 , evacuated, to enable repetition of the cycle with a new preform 3 .
  • container 2 exhibits a negative gradient of crystallinity in the area of its inside wall 42 .
  • the crystallinity measured from the side of inside wall 42 is in this case much less (about 30%) than the crystallinity measured from the side of outside wall 43 .
  • the mechanical resistance to deformation of a container 2 is greater than that of a container obtained by a process without ignition (See, the comparative example).
  • the retraction rate of the container is less than or equal to 1%.
  • formed container 2 undergoes a heat setting, from the side of its outside wall 43 in contact with the heated wall of mold 5 . It thus benefits, over a certain thickness of its outside wall 43 , from a contribution of crystallinity by thermal means, while its inside wall 42 , which becomes completely (or almost completely) amorphous following its fusion, retains a high proportion of amorphous matter, with a comparatively lower rate of crystallinity.
  • the high rate of crystallinity of the side of outside wall 43 gives container 2 a rigidity equivalent to that of a container with constant crystallinity (such as a simply thermoset container, obtained by the process described in the comparative example, that is to say without igniting an explosive gaseous mixture), the portion of high crystallinity matter (comprising outside wall 43 ) acting in the manner of a brace with respect to the portion of low crystallinity matter (comprising inside wall 42 ).
  • a container with constant crystallinity such as a simply thermoset container, obtained by the process described in the comparative example, that is to say without igniting an explosive gaseous mixture
  • the thickness of inside wall 42 corresponds to the thickness of segment A, as cut out for the needs of the DSC analysis (See above). Measurements have shown that the gradient of crystallinity does not extend beyond segment C. Consequently, inside wall 42 affected by the negative gradient of crystallinity exhibits a thickness less than 100 ⁇ m, and more likely less than approximately 50 ⁇ m.
  • mold 5 is heated such that such that it exhibits on the side of its inside wall a temperature of approximately 160° C.
  • the material of the preform 3 is a PET.
  • the reactive gas is hydrogen (H 2 ).
  • the air/hydrogen gaseous mixture is made while maintaining a hydrogen proportion in volume between 4% and 18%, preferably 6%.
  • a first pre-blowing operation consisting of stretching preform 3 by sliding rod 12 , and to simultaneously pre-blow it by opening the electromagnetic valves EV 1 and EV 2 to introduce into preform 3 an air and reactive gas mixture at a pressure between approximately 5 and 20 bars ( FIGS. 5A to 5C , lines 1 and 2 on FIG. 6B ).
  • This first operation of a predetermined duration ⁇ 1 ends by the closing of the electromagnetic valves EV 1 and EV 2 after rod 12 has ended its travel having reached the bottom of mold 7 , and the threshold for the plastic outflow of the material has been exceeded (which is indicated on the pressure curve by a first pressure peak, at approximately 8 to 10 bars).
  • a second operation consists of igniting the gaseous mixture by ignition of spark plug 36 ( FIG. 5D , line 3 in FIG. 6B ).
  • spark plug 36 FIG. 5D , line 3 in FIG. 6B .
  • a deflagration occurs in container 2 that is being formed, which is accompanied by an abrupt increase of the temperature (which reaches hundreds of degrees Celsius) and of the pressure (which exceeds 40 bars—on the curve of FIG. 6A the corresponding peak pressure is clipped due to reasons of scale).
  • the duration ⁇ 2 of the ignition of the mixture is extremely brief (less than 25 ms), but the increased pressure that accompanies it is sufficient to pin the matter flat against the wall of mold 5 , thus forming container 2 .
  • a third operation consists of maintaining in container 2 the residual gas (essentially a mixture of water vapor coming from the combustion of hydrogen, with possible traces of NO x ), for a predetermined duration ⁇ 3 (between 200 and 300 ms) while keeping all the electromagnetic valves EV 1 , EV 2 , EV 3 , EV 4 closed, so as to permit the reduction of the temperature and the pressure in container 2 ( FIG. 5E ).
  • the residual gas essentially a mixture of water vapor coming from the combustion of hydrogen, with possible traces of NO x
  • a fourth operation consists of opening third electromagnetic valve EV 3 to introduce into container 2 , via holes 13 arranged in rod 12 , high pressure air (between approximately 30 and 40 bars) at ambient temperature and thus keep pinned flat against the wall of mold 5 container 2 formed at the time of the ignition operation ( FIG. 5F , line 4 on FIG. 6B ).
  • a predetermined duration ⁇ 4 preferably less than 1000 ms
  • a fifth operation consists of making an air sweep of container 2 , while keeping third electromagnetic valve EV 3 open to continue introducing high pressure air ( FIG. 6B , line 4 ) at ambient temperature into container 2 , while simultaneously opening fourth electromagnetic valve EV 4 to permit pressurized air to be evacuated ( FIG. 6B , line 5 ).
  • An air circulation is thus generated in container 2 while maintaining it under pressure (between 10 and 15 bars), which continues to pin it flat against the wall of mold 5 while cooling it (at least on the same side of its inside wall 42 ), so that upon emerging from mold 5 it retains the shape that the latter gives it ( FIG. 5G ).
  • This sweep operation is performed for a predetermined duration ⁇ 5 , between 200 et 2000 ms.
  • a sixth operation consists of degassing container 2 , by closing third electromagnetic valve EV 3 ( FIG. 6B , line 4 ) and leaving fourth electromagnetic valve EV 4 open for a preset duration ⁇ 6 (between 100 and 500 ms), to allow the air to escape ( FIG. 5H ) until the pressure prevailing inside container 2 has about attained the atmospheric pressure ( FIG. 6B , line 5 ).
  • the fourth electromagnetic valve EV 4 is closed, mold 5 opened and container 2 evacuated to enable repetition of the cycle with a new preform.
  • container 2 exhibits a negative gradient of crystallinity in the area of its inside wall 42 .
  • the crystallinity measured from the side of inside wall 42 is in this case much less (about 30%) than the crystallinity measured from the side of outside wall 43 .
  • the mechanical resistance to deformation of a container 2 is greater than that of a container obtained by a process without ignition (See, the comparative example).
  • the retraction rate of the container is less than or equal to 1%.
  • formed container 2 undergoes a heat setting, from the side of its outside wall 43 in contact with the heated wall of mold 5 . It thus benefits, over a certain thickness of its outside wall 43 , from a contribution of crystallinity by thermal means, while its inside wall 42 , which becomes completely (or almost completely) amorphous following its fusion, retains a high proportion of amorphous matter, with a comparatively lower rate of crystallinity.
  • the high rate of crystallinity of the side of outside wall 43 gives container 2 a rigidity equivalent to that of a container with constant crystallinity (such as a simply thermoset container, obtained by the process described in the comparative example, that is to say without igniting an explosive gaseous mixture), the portion of high crystallinity matter (comprising outside wall 43 ) acting in the manner of a brace with respect to the portion of low crystallinity matter (comprising inside wall 42 ).
  • a container with constant crystallinity such as a simply thermoset container, obtained by the process described in the comparative example, that is to say without igniting an explosive gaseous mixture
  • the thickness of inside wall 42 corresponds to the thickness of segment A, as cut out for the needs of the DSC analysis (See above). Measurements have shown that the gradient of crystallinity does not extend beyond segment C. Consequently, inside wall 42 affected by the negative gradient of crystallinity exhibits a thickness less than 100 ⁇ m, and more likely less than approximately 50 ⁇ m.
  • mold 5 is heated such that it exhibits on the side of its inside wall a temperature of approximately 130° C.
  • the material of the preform 3 is a PET.
  • the reactive gas is hydrogen (H 2 ).
  • the air/hydrogen gaseous mixture is made while maintaining a hydrogen proportion in volume between 4% and 18%, preferably 6%.
  • a first operation consists of stretching preform 3 by sliding rod 12 , and simultaneously pre-blowing it by opening electromagnetic valves EV 1 and EV 2 to introduce into preform 3 an air and reactive gas mixture at a pressure between approximately 5 and 20 bars ( FIGS. 7A to 7C , lines 1 and 2 on FIG. 8B ).
  • This first operation of a predetermined duration ⁇ 1 ends by the closing of the electromagnetic valves EV 1 and EV 2 after rod 12 has ended its travel having reached the bottom of mold 7 , and the threshold for the plastic outflow of the material has been exceeded (which is indicated on the pressure curve by a first pressure peak, at approximately 8 to 10 bars).
  • a second operation consists of igniting the gaseous mixture by ignition of spark plug 36 ( FIG. 7D , line 3 in FIG. 8B ).
  • spark plug 36 FIG. 7D , line 3 in FIG. 8B .
  • a deflagration occurs in container 2 that is being formed, which is accompanied by an abrupt increase of the temperature (which reaches hundreds of degrees Celsius) and of the pressure (which exceeds 40 bars—on the curve of FIG. 7A ; the corresponding peak pressure is clipped due to reasons of scale).
  • the duration of ⁇ 2 of the ignition of the mixture is extremely brief (less than 25 ms), but the increased pressure that accompanies it is sufficient to pin the substance flat against the wall of mold 5 , thus forming container 2 .
  • a third operation consists of maintaining in container 2 a residual gas (essentially a mixture of water vapor coming from the combustion of hydrogen, with possible traces of NO x ), for a predetermined duration ⁇ 3 (between 200 and 300 ms) while keeping all the electromagnetic valves EV 1 , EV 2 , EV 3 , EV 4 closed, so as to permit the reduction of the temperature and the pressure in container 2 ( FIG. 8E ).
  • a residual gas essentially a mixture of water vapor coming from the combustion of hydrogen, with possible traces of NO x
  • ⁇ 3 between 200 and 300 ms
  • a fourth operation consists of degassing container 2 , by closing the fourth electromagnetic valve EV 4 for a preset duration 4 (between 100 and 200 ms), to allow the air to escape ( FIG. 7F ) until the pressure prevailing inside container 2 has attained about the atmospheric pressure ( FIG. 8B , line 5 ).
  • a fifth operation consists of re-opening electromagnetic valves EV 1 and EV 2 to introduce into the container an air and reactive gas mixture at a pressure between approximately 5 and 20 bars ( FIG. 7G , lines 1 and 2 in FIG. 8B ).
  • This fifth operation of a predetermined duration ⁇ 5 (less than 250 ms) ends by the closing of the electromagnetic valves EV 1 et EV 2 after the pressure in container 2 has reached a value between 5 and 20 bars.
  • a sixth operation consists of igniting the gaseous mixture by ignition of spark plug 36 ( FIG. 7H , line 3 in FIG. 8B ).
  • spark plug 36 FIG. 7H , line 3 in FIG. 8B .
  • a deflagration is produced in container 2 , which is accompanied by an abrupt increase in the temperature (which again reaches several hundred degrees Celsius) and the pressure (which again exceeds 40 bars, the corresponding peak pressure likewise being clipped in FIG. 8A ).
  • the duration ⁇ 6 of the ignition of the mixture is extremely brief (less than 25 ms).
  • a seventh operation consists of maintaining in container 2 a residual gas (essentially a mixture of water vapor coming from the combustion of hydrogen, with possible traces of NO x ), for a predetermined duration ⁇ 7 (between 200 and 300 ms), while keeping all the electromagnetic valves EV 1 , EV 2 , EV 3 , EV 4 closed, so as to permit the reduction of the temperature and the pressure in container 2 ( FIG. 7I ).
  • a residual gas essentially a mixture of water vapor coming from the combustion of hydrogen, with possible traces of NO x
  • ⁇ 7 between 200 and 300 ms
  • An eighth operation consists of opening the third electromagnetic valve EV 3 to introduce into container 2 , via holes 13 arranged in rod 12 , high pressure air (between approximately 30 and 40 bars) at ambient temperature and thus keep pinned flat against the wall of mold 5 container 2 formed at the time of the ignition operation ( FIG. 7J , line 4 on FIG. 8B ).
  • a predetermined duration ⁇ 8 preferably less than 300 ms
  • a ninth operation consists of making an air sweep of the container, while keeping the third electromagnetic valve EV 3 open to continue introducing high pressure air ( FIG. 8B , line 4 ) at ambient temperature into container 2 , while simultaneously opening the fourth electromagnetic valve EV 4 to permit pressurized air to be evacuated ( FIG. 8B , line 5 ).
  • An air circulation is thus generated in container 2 while maintaining it under pressure (between 10 and 15 bars), which continues to pin it flat against the wall of mold 5 while cooling it (at least on the side of its inside wall 42 ), so that upon emerging from mold 5 it retains the shape that the latter gives it ( FIG. 7K ).
  • This sweep operation is performed for a predetermined duration ⁇ 9 , between 200 et 2000 ms.
  • a tenth operation consists of degassing container 2 , by closing the third electromagnetic valve EV 3 ( FIG. 8B , line 4 ) and leaving the fourth electromagnetic valve EV 4 for a preset duration ⁇ 10 (between 100 and 500 ms), to allow the air to escape ( FIG. 7L ) until the pressure prevailing inside container 2 has about attained atmospheric pressure ( FIG. 8B , line 5 ).
  • the fourth electromagnetic valve EV 4 is closed, mold 5 opened and container 2 evacuated to enable repetition of the cycle with a new preform.
  • container 2 exhibits a negative gradient of crystallinity in the area of its inside wall 42 .
  • the crystallinity measured from the side of inside wall 42 is in this case much less (about 50%) than the crystallinity measured from the side of outside wall 43 .
  • the mechanical resistance to deformation of such a container 2 is greater than that of a container obtained by a process without ignition (See the comparative example).
  • the retraction rate of the container is less than or equal to 1%.
  • formed container 2 undergoes a heat setting, of the side of its outside wall 43 in contact with the heated wall of mold 5 . It thus benefits, over a certain thickness of its outside wall 43 , from a contribution of crystallinity by thermal means, while its inside wall 42 , which becomes completely (or almost completely) amorphous following its fusion, retains a high proportion of amorphous matter, with a comparatively lower rate of crystallinity.
  • the high rate of crystallinity of the side of outside wall 43 gives container 2 a rigidity equivalent to that of a container with constant crystallinity (such as a simply thermoset container, obtained by the process described in the comparative example, that is to say without igniting an explosive gaseous mixture), the portion of high crystallinity matter (comprising outside wall 43 ) acting in the manner of a brace with respect to the portion of low crystallinity matter (comprising inside wall 42 ).
  • a container with constant crystallinity such as a simply thermoset container, obtained by the process described in the comparative example, that is to say without igniting an explosive gaseous mixture
  • the thickness of inside wall 42 corresponds to the thickness of segment A, as cut out for the needs of the DSC analysis (See above). Measurements have shown that the gradient of crystallinity does not extend beyond segment C. Consequently, inside wall 42 affected by the negative gradient of crystallinity exhibits a thickness less than 100 ⁇ m, and more likely less than approximately 50 ⁇ m.
  • This endothermic peak found between the vitreous transition temperature (occurring around 80° C.) and the fusion peak, is a crystallization peak, attesting to the amorphous character of the matter of segment A, of the side of inside wall 42 of container 2 .
  • the absence of such a crystallization peak on the curves of the other segments B to E attests to the semi-crystalline character of the matter in particular of the side of the outside wall 43 .
  • container 2 can be considered, at the end of its manufacture, to be amorphous on the side of its inside wall 42 .
  • mold 5 is heated such that it exhibits on the side of its inside wall a temperature of approximately 130° C.
  • the material of the preform 3 is a PET.
  • the reactive gas is hydrogen (H 2 ).
  • the air/hydrogen gaseous mixture is made while maintaining a hydrogen proportion in volume between 4% and 18%, preferably 6%.
  • a first operation consists of stretching preform 3 by sliding rod 12 , and simultaneously pre-blowing it by opening first electromagnetic valve EV 1 to introduce into preform 3 an air and reactive gas mixture at a pressure between approximately 5 and 20 bars ( FIGS. 9A to 9C , line 1 on FIG. 10B ).
  • This first operation of a predetermined duration ⁇ 1 ends by the closing of electromagnetic valve EV 1 and after rod 12 has ended its travel, having reached mold bottom 7 , and the threshold for the plastic outflow of the material has been exceeded (which is indicated on the pressure curve by a first pressure peak, at approximately 8 to 10 bars).
  • a second operation consists of blowing container 2 by opening the third electromagnetic valve EV 3 to introduce into container 2 being formed, via holes 13 arranged in rod 12 , high pressure air (between approximately 30 and 40 bars) at ambient temperature, so as to keep container 2 pinned flat against the wall of mold 5 ( FIG. 9D , line 4 on FIG. 10B ).
  • a predetermined duration ⁇ 2 preferably less than 300 ms
  • fourth electromagnetic valve EV 4 is kept closed.
  • a third operation consists of degassing container 2 , by opening the fourth electromagnetic valve EV 4 for a preset duration ⁇ 3 (between 100 and 200 ms), to allow the air to escape ( FIG. 9E ) until the pressure prevailing inside container 2 has attained about the atmospheric pressure ( FIG. 10B , line 5 ).
  • a fourth operation consists of re-opening electromagnetic valves EV 1 and EV 2 to introduce into container 2 an air and reactive gas mixture at a pressure between approximately 5 and 20 bars ( FIG. 9F , lines 1 and 2 on FIG. 10B ).
  • This fourth operation of a predetermined duration ⁇ 4 (less than 250 ms) ends by the closing of electromagnetic valves EV 1 and EV 2 after the pressure in container 2 has reached a value between 5 and 20 bars.
  • a fifth operation consists of igniting the gaseous mixture by ignition of spark plug 36 ( FIG. 9G , line 3 in FIG. 10B ).
  • spark plug 36 FIG. 9G , line 3 in FIG. 10B .
  • a deflagration occurs in container 2 , accompanied by an abrupt increase of the temperature (which reaches several hundred degrees Celsius) and of the pressure (which exceeds 40 bars—on the curve of FIG. 10A ; the corresponding peak pressure is clipped due to reasons of scale).
  • the duration ⁇ 5 of ignition of the mixture is extremely brief (less than 25 ms).
  • a sixth operation consists of maintaining in container 2 a residual gas (essentially a mixture of air and water vapor coming from the combustion of hydrogen, with possible traces of NO x ), for a predetermined duration ⁇ 6 (between 200 and 300 ms), while keeping all the electromagnetic valves EV 1 , EV 2 , EV 3 , EV 4 closed, so as to permit the reduction of the temperature and the pressure in container 2 ( FIG. 9H ).
  • a residual gas essentially a mixture of air and water vapor coming from the combustion of hydrogen, with possible traces of NO x
  • ⁇ 6 between 200 and 300 ms
  • An seventh operation consists of opening the third electromagnetic valve EV 3 to introduce into container 2 , via holes 13 arranged in rod 12 , high pressure air (between approximately 30 and 40 bars) at ambient temperature and thus keep pinned flat against the wall of mold 5 container 2 formed at the time of the ignition operation ( FIG. 9I , line 4 on FIG. 10B ).
  • a predetermined duration ⁇ 7 preferably less than 300 ms
  • fourth electromagnetic valve EV 4 is kept closed.
  • An eighth operation consists of making an air sweep of container 2 , while keeping third electromagnetic valve EV 3 open to continue introducing high pressure air ( FIG. 10B , line 4 ) at ambient temperature into container 2 , while simultaneously opening the fourth electromagnetic valve EV 4 to permit pressurized air to be evacuated ( FIG. 10B , line 5 ).
  • An air circulation is thus generated in container 2 , while maintaining it under pressure (between 10 and 15 bars), which continues to pin it flat against the wall of mold 5 , while cooling it (at least on the same side of its inside wall), so that upon emerging from mold 5 it retains the shape that the latter gives it ( FIG. 9J ).
  • This sweep operation is performed for a predetermined duration ⁇ 8 , between 200 et 2000 ms.
  • a ninth operation consists of degassing container 2 , by closing third electromagnetic valve EV 3 ( FIG. 10B , line 4 ) and leaving fourth electromagnetic valve EV 4 open for a preset duration ⁇ 9 (between 100 and 500 ms), to allow the air to escape ( FIG. 9K ) until the pressure prevailing inside container 2 has about attained atmospheric pressure ( FIG. 10B , line 5 ).
  • fourth electromagnetic valve EV 4 is closed, mold 5 opened and container 2 evacuated to enable repetition of the cycle with a new preform.
  • container 2 exhibits a negative gradient of crystallinity in the area of its inside wall 42 .
  • the crystallinity measured on the side of inside wall 42 is in this case much less (about 20%) than the crystallinity measured on the side of outside wall 43 .
  • the mechanical resistance to deformation of such a container 2 is greater than that of a container obtained by a process without ignition (See the comparative example).
  • the retraction rate of the container is less than or equal to 1%.
  • formed container 2 undergoes a heat setting, of the side of its outside wall 43 in contact with the heated wall of mold 5 . It thus benefits, over a certain thickness of its outside wall 43 , from a contribution of crystallinity by thermal means, while its inside wall 42 , which becomes completely (or almost completely) amorphous following its fusion, retains a high proportion of amorphous matter, with a comparatively lower rate of crystallinity.
  • the high rate of crystallinity of the side of outside wall 43 gives container 2 a rigidity equivalent to that of a container with constant crystallinity (such as a simply thermoset container, obtained by the process described in the comparative example, that is to say without igniting an explosive gaseous mixture), the portion of high crystallinity matter (comprising outside wall 43 ) acting in the manner of a brace with respect to the portion of low crystallinity matter (comprising inside wall 42 ).
  • a container with constant crystallinity such as a simply thermoset container, obtained by the process described in the comparative example, that is to say without igniting an explosive gaseous mixture
  • the thickness of inside wall 42 corresponds to the thickness of segment A, as cut out for the needs of the DSC analysis (See above). Measurements have shown that the gradient of crystallinity does not extend beyond segment C. Consequently, inside wall 42 affected by the negative gradient of crystallinity exhibits a thickness less than 100 ⁇ m, and more likely less than approximately 50 ⁇ m.
  • FIGS. 11 A to 11 F, 12 A, 12 B, 16 are identical to FIGS. 11 A to 11 F, 12 A, 12 B, 16 )
  • mold 5 is heated such that such that it exhibits on the side of its inside wall a temperature of approximately 160° C.
  • the material of the preform is a PET.
  • a first operation consists of stretching preform 3 by sliding rod 12 , and simultaneously pre-blowing it by opening the first electromagnetic EV 1 to introduce into preform 3 an air and reactive gas mixture at a pressure between approximately 5 and 20 bars ( FIGS. 11A to 11C , line 1 on FIG. 12B ).
  • This first operation of a predetermined duration ⁇ 1 ends by the closing of electromagnetic valve EV 1 after rod 12 has ended its travel having reached the bottom of mold 7 , and the threshold for the plastic outflow of the material has been exceeded (which is indicated on the pressure curve by a first pressure peak, at approximately 8 to 10 bars).
  • a second operation consists of blowing preform 3 by opening the third electromagnetic valve EV 3 to introduce into preform 3 , via holes 13 arranged in rod 12 , high pressure air (between approximately 30 and 40 bars) at ambient temperature, so as to pin container 2 flat against the wall of mold 5 ( FIG. 11D , line 4 on FIG. 12B ).
  • a predetermined duration ⁇ 2 between 500 and 1200 ms
  • fourth electromagnetic valve EV 4 is kept closed.
  • a third operation consists of making an air sweep of container 2 , while keeping third electromagnetic valve EV 3 open to continue introducing high pressure air at ambient temperature into container 2 via holes 13 arranged in rod 12 ( FIG. 12B , line 4 ), while simultaneously opening the fourth electromagnetic valve EV 4 to permit pressurized air to be evacuated ( FIG. 12B , line 5 ).
  • An air circulation is thus generated in container 2 while maintaining it under pressure (between 10 and 15 bars), so as to pin it against mold 5 ( FIG. 12E ).
  • This sweep operation is performed for a predetermined duration ⁇ 3 , between 500 et 800 ms.
  • a fourth operation consists of degassing container 2 , by closing the third electromagnetic valve EV 3 ( FIG. 12B , line 4 ) and leaving the fourth electromagnetic valve EV 4 open for a preset duration ⁇ 5 (between 200 and 500 ms), to allow the air to escape ( FIG. 11F ) until the pressure prevailing inside container 2 has attained about the atmospheric pressure ( FIG. 12B , line 5 ).
  • the fourth electromagnetic valve EV 4 is closed, mold 5 opened and container 2 evacuated to enable repetition of the cycle with a new preform.
  • Segment Crystallinity A (inside wall) 31 B 24 C 28 D 35 E (outside wall) 30
  • a thermal analysis of this container 2 is performed by DSC, by taking a sample similar to that used for measuring the crystallinity, and by cutting it in the same manner to obtain five similar segments A, B, C, D and E.
  • the DSC curves of the five segments are consolidated on the thermogram of FIG. 16 . It is apparent that the curves all exhibit a single endothermic peak of fusion around 250° C., attesting to the semi-crystalline character of the matter throughout the thickness of container 2 .
  • the mechanical resistance to deformation of such a container 2 is less than that of a container obtained by a process with ignition.
  • a liquid temperature consisting of 90° C. for example, the retraction rate of the container is 2%.
  • filling is impossible unless container 2 is deformed (the container is pumped like a barrel) beyond what is commercially permissible.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
  • Containers Having Bodies Formed In One Piece (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)
US12/663,442 2007-06-07 2008-06-06 Method for making vessels for improving the mechanical strength thereof Abandoned US20100237528A1 (en)

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FR0704064A FR2917004B1 (fr) 2007-06-07 2007-06-07 Procede de fabrication de recipients par soufflage permettant d'ameliorer leur tenue mecanique
FR0704064 2007-06-07
PCT/FR2008/000771 WO2009004192A2 (fr) 2007-06-07 2008-06-06 Procede de et machine pour la fabrication de recipients permettant d ' ameliorer leur tenue mecanique

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US20130053813A1 (en) * 2007-07-31 2013-02-28 B. Braun Medical Inc. Flexible storage container
US8864490B2 (en) 2010-07-20 2014-10-21 Discma Ag Device for injecting at least two pressurized fluids into the neck of a container in order to form said container
CN104329521A (zh) * 2014-10-20 2015-02-04 佛山市百进一精密机械有限公司 一种塑料瓶拉伸杆安装结构
US20150209997A1 (en) * 2012-10-29 2015-07-30 Sidel Participations Method for blow-moulding containers, and machine for said method
US9610744B2 (en) 2011-12-27 2017-04-04 Discma Ag Blow molding device and a method for manufacturing a container
US9656419B2 (en) 2012-08-09 2017-05-23 Nissei Asb Machine Co., Ltd. Blow nozzle and blow molding machine
US20210113947A1 (en) * 2019-10-16 2021-04-22 Huvis Corporation Nonwoven fabric for cabin air filter comprising low melting polyester fiber

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JP5747413B2 (ja) * 2011-12-27 2015-07-15 株式会社吉野工業所 ２軸延伸ブロー成形装置及び容器の製造方法
JP5747412B2 (ja) * 2011-12-27 2015-07-15 株式会社吉野工業所 ブロー成形装置及び容器の製造方法
JP5872361B2 (ja) * 2012-03-30 2016-03-01 株式会社吉野工業所 ブロー成形装置及び合成樹脂製容器の製造方法
CN104136194B (zh) * 2011-12-27 2017-08-11 帝斯克玛股份有限公司 吹塑成型装置和吹塑成型容器的制造方法
JP6184660B2 (ja) * 2012-01-31 2017-08-23 株式会社吉野工業所 ブロー成形装置及び容器の製造方法
JP6072250B2 (ja) 2012-08-03 2017-02-01 株式会社吉野工業所 容器を製造する方法および装置
CN114043706A (zh) * 2021-11-15 2022-02-15 襄阳光瑞汽车零部件有限公司 一种预埋固定镶件式一体吹塑成型工艺

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FR2917004B1 (fr) 2012-10-26
JP2010528900A (ja) 2010-08-26
WO2009004192A2 (fr) 2009-01-08
CN101790451B (zh) 2014-07-02
EP2152495A2 (fr) 2010-02-17
FR2917004A1 (fr) 2008-12-12
CN101790451A (zh) 2010-07-28
EP2152495B1 (fr) 2016-01-06

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