EP1423246A1 - Methods for making polyethylene terephthalate (pet) preforms and containers such as food bottles, containers and intermediate preforms obtained - Google Patents

Methods for making polyethylene terephthalate (pet) preforms and containers such as food bottles, containers and intermediate preforms obtained

Info

Publication number
EP1423246A1
EP1423246A1 EP02791514A EP02791514A EP1423246A1 EP 1423246 A1 EP1423246 A1 EP 1423246A1 EP 02791514 A EP02791514 A EP 02791514A EP 02791514 A EP02791514 A EP 02791514A EP 1423246 A1 EP1423246 A1 EP 1423246A1
Authority
EP
European Patent Office
Prior art keywords
preforms
pet
containers
container
preform
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP02791514A
Other languages
German (de)
French (fr)
Inventor
Gérard Denis
Murielle Vigny
Gérard Perez
Jean-Luc Lepage
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nestle Waters Management and Technology SAS
Tergal Industries
Original Assignee
TERGAL FIBRES SA
TERGAL FIBRES SA
Nestle Waters Management and Technology SAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by TERGAL FIBRES SA, TERGAL FIBRES SA, Nestle Waters Management and Technology SAS filed Critical TERGAL FIBRES SA
Publication of EP1423246A1 publication Critical patent/EP1423246A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B11/00—Making preforms
    • B29B11/06—Making preforms by moulding the material
    • B29B11/08—Injection 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
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/20—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer
    • B29C2949/22—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer at neck portion
    • 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
    • B29C2949/20—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer
    • B29C2949/24—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer at flange portion
    • 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
    • B29C2949/20—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer
    • B29C2949/26—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer at body portion
    • 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
    • B29C2949/20—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer
    • B29C2949/28—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer at bottom portion
    • 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
    • B29C2949/30—Preforms or parisons made of several components
    • B29C2949/3024—Preforms or parisons made of several components characterised by the number of components or by the manufacturing technique
    • 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
    • B29C2949/30—Preforms or parisons made of several components
    • B29C2949/3032—Preforms or parisons made of several components having components being injected
    • 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
    • B29C49/0005—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor characterised by the material
    • 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
    • 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
    • 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
    • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
    • B29K2105/0094—Condition, form or state of moulded material or of the material to be shaped having particular viscosity
    • 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
    • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
    • B29K2105/25—Solid
    • B29K2105/253—Preform
    • B29K2105/258—Tubular
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/712—Containers; Packaging elements or accessories, Packages
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
    • Y10T428/1352—Polymer or resin containing [i.e., natural or synthetic]

Definitions

  • the present invention relates to the field of synthetic materials commonly called plastics and their transformation for the production of packaging or packaging products.
  • the invention particularly relates to the field of the manufacture of polyester containers intended for food use such as bottles, in particular bottles intended to contain water.
  • Polyesters and in particular polyethylene terephthalate (PET) and its copolymers are well known for the manufacture of all kinds of packaging or packaging materials, such as, for example, bottles, cans, boxes, films, bags, etc.
  • PET and its derivatives are widely used in the manufacture of bottles, in particular bottles intended to contain water, still or sparkling, fruit juices, etc.
  • the PET polymers used in the production of bottles for food use have employment properties, in particular a so-called “barrier” effect to the various gases (water vapor, oxygen, carbon dioxide, etc.) which increase with the intrinsic viscosity (VI) of the material used, that is to say with the length of the chains of the polymers used.
  • gases water vapor, oxygen, carbon dioxide, etc.
  • materials with good gas impermeability properties are generally viscous (VI between 0.72 dl / g and 0.83 dl / g), therefore difficult to implement industrially and expensive to produce and use .
  • relatively large amounts of acetaldehyde are formed, which constitutes an additional problem when the bottles produced are intended to contain certain drinks, for example mineral water. Indeed, even minute quantities of acetaldehyde (of the order of 20 ppm) in the material forming the bottle are enough to give an undesired fruity taste to the drinks contained therein.
  • the problem posed by the present invention therefore consists in overcoming the aforementioned drawbacks and in proposing a process for manufacturing preforms and PET containers which does not require an SSP step while guaranteeing the obtaining of containers whose properties physical and chemical meet current or future requirements.
  • the present invention relates to a first method for manufacturing PET resin preforms as well as the preforms obtained by the implementation of said method.
  • the synthetic resins used are usually transformed by injection and molding into preforms, that is to say into hollow bodies substantially in the form of tubes (possibly provided at their open ends with bottle necks) to then be blown or stretched during the manufacturing of the container itself.
  • the present invention also relates to a second method of manufacturing PET resin containers, such as bottles for food use, from the aforementioned preforms as well as said PET containers which result therefrom.
  • the present invention further relates to a PET container, in particular a food container, in particular a food bottle, preferably a food bottle intended to contain water, as well as a third method of manufacturing containers.
  • a PET container in particular a food container, in particular a food bottle, preferably a food bottle intended to contain water, as well as a third method of manufacturing containers. in PET combining the first and second separate processes previously mentioned.
  • the process for manufacturing PET resin preforms according to the invention is characterized in that it consists in using a PET resin with an intrinsic viscosity (VI) of less than 0.65 dl / g.
  • the preform capable of being obtained by the implementation of this first process is characterized in that the intrinsic viscosity (VI) of the polyester forming the walls of said preform is between 0.45 dl / g and 0.65 dl / g.
  • the second method of manufacturing PET resin containers, such as bottles for food use from a preform according to the invention or obtained by implementing the first method according to the invention is characterized in that it essentially comprises the steps consisting in:
  • blowing the pre-blown preform by injecting a pressurized gas at a second higher pressure for a second period
  • the third method of manufacturing PET containers according to the invention is characterized in that it essentially comprises the steps consisting in: - manufacturing a preform from said PET resin thanks to the implementation of the first method according to the invention and / or use a preform according to the invention and,
  • the PET container obtained from a preform according to the present invention or capable of being obtained by implementing the second process above is characterized in that the intrinsic viscosity (VI) of the polyester forming the walls of said container is between 0.45 dl / g and 0.65 dl / g.
  • VI intrinsic viscosity
  • the process for manufacturing PET resin preforms according to the invention is characterized in that it consists in using a polyester resin with an intrinsic viscosity (VI) of less than 0.65 dl / g.
  • VI intrinsic viscosity
  • the intrinsic viscosity (VI) is between 0.45 dl / g and 0.65 dl / g.
  • intrinsic viscosity is meant the viscosity of a zero concentration polymer solution. This value is calculated according to formula (I) below from the determination of a viscosity index (IV) in dl / g measured on a polymer solution at 0.5 g of polymer / 100 ml of a solvent consisting of orthodichlorobenzene and phenol (50/50 by weight) at 25 ° C, according to ISO standard 1628/5 of June 15, 1986.
  • the intrinsic viscosity ( VI) in dl / g is calculated by the following formula (I):
  • the process of the present invention it becomes possible to dispense with the PCS or SSP stage present in the known processes and in particular used to increase the intrinsic viscosity (VI).
  • This elimination brings significant gains in energy, in material as well as in time, knowing that the stage of postcondensation in solid phase generally takes place at more than 200 ° C under a flow of nitrogen and can last from 10 hours to 30 hours.
  • the present invention not only allows productivity gains and substantial savings in materials at the industrial level, but also the obtaining of a final product with technical characteristics equivalent to those of existing or even superior products, as demonstrated below.
  • the PET resins suitable for implementing the process according to the invention are polyesters of polyethylene terephthalate (PET), that is to say saturated thermoplastic polyesters whose generic name covers a whole family of polymers more or less copolymerized.
  • the preferred monomers are terephthalic acid and ethylene glycol leading to polyethylene terephthalate better known under the abbreviation PET as indicated above.
  • PET covers both a homopolymer obtained solely from monomers of terephthalic acid or its esters such as dimethyl terephthalate and ethylene glycol monomers as well as copolymers comprising at least 92.5% by number of repeating units of ethylene terephthalate.
  • the polyester comprises at least one crystallization retarder allowing, in particular during the cooling of the molded or injected article such as a preform, to slow down or delay the crystallization of the polyester so as to obtain crystallization in very small crystals avoiding spherulitic crystallization and being able to manufacture a transparent article, the walls of which do not have haze or "haze", with acceptable mechanical properties.
  • crystallization retarding agents are difunctional compounds such as diacids and or diols added to the mixture of monomers before or during the polymerization of the polyester.
  • crystallization retarding agent of examples of diacids, isophthalic acid, naphthalenedicarboxylic acid, cyclohexane dicarboxylic acid, cyclohexane diacetic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid and as examples of diols, there may be mentioned aliphatic diols comprising from 3 to 20 carbon atoms, cycloaliphatic diols from 6 to 20 carbon atoms, diols aromatics comprising from 6 to 14 carbon atoms and their mixtures such as di-ethylene glycol, tri-ethylene glycol, isomers of 1,4-cyclohexane di-methanol, 1,3-propane diol, 1,4- butane diol, 1,5-pentane diol, (2,4) -3 methylpentanediol, (1,4) -2 methylpentanedi
  • Diethylene glycol is often present in polyesters inherently because it is formed during the synthesis by condensation of two molecules of ethylene glycol.
  • DEG diethylene glycol
  • either diethylene glycol is added to the monomer mixtures, or the polyester synthesis conditions are controlled to limit the formation of diethylene glycol.
  • the molar concentration of diethylene glycol in the polyester relative to the numbers of moles of diacid monomers is less than 3.5%, preferably less than 2 mol%.
  • the molar concentration relative to the number of moles of all of the diacids in the mixture of monomers and therefore in the polyester obtained is advantageously less than 7.5%, with the condition that the DEG content must be deducted from this value if it is present.
  • the total molar concentration of crystallization retardant must be less than 7.5% as indicated in European Patent No. 41035.
  • the polyester may comprise a mixture of agents for retarding crystallization of the acid and / or diol type.
  • the processes for injecting preforms and blowing hollow containers make it possible to control in particular the cooling rates to avoid spherulitic crystallization of the resin or in the case where the bottles to be produced are not translucent such as milk bottles by
  • the total concentration of crystallization retarder can be very low, for example of the order of 1%, or even zero with the exception of the DEG formed during the synthesis of the polyester.
  • the polyester of the invention advantageously comprises less than 4% of isophthalic acid and less than 4% of diethylene glycol, content expressed in% of moles of crystallization retarder relative to the number of moles of all of the diacid monomers.
  • the said polyester does not contain a retardation of crystallization but however, it contains DEG coming from the manufacture of the said polyester.
  • the main steps in the synthesis of such a resin are as follows. First of all, a "pasting" is carried out, that is to say a mixture of the diacids in the form of powders with the liquid glycols. The mixture is then esterified in a conventional manner by heating and simultaneous extraction of the water formed.
  • the actual polymerization is carried out by heating the reaction mixture under vacuum to a temperature of between approximately 260 ° C. and 280 ° C. by extracting glycol, said polymerization possibly being preceded by a first prepolymerization step under similar conditions.
  • the reaction is stopped when a viscous mixture having the appearance of honey or molasses is obtained.
  • This viscous mixture can then be passed through a rod ring known per se.
  • the rods obtained are then immersed in a tank of cooling water and then cut out in a granulator to obtain small solid granules, for example in the form of cubes of 2 mm to 3 mm on a side.
  • the PET resin granules obtained are amorphous and transparent.
  • the present invention provides a process for spherolitic crystallization of the PET resin, characterized in that it consists in heating the resin to a temperature between 120 ° C and 200 ° C.
  • the spherulitic crystallization is carried out with stirring in order to avoid sticking between the granules.
  • the transparent and sticky amorphous granules are thus transformed into opaque white crystallized granules (milky appearance) which no longer stick to each other and which have an intrinsic viscosity (VI) of less than 0.65 dl / g, preferably between 0.45 dl / g and 0.65 dl / g.
  • the spherulitic crystallization is carried out in a fluidized bed. This ensures better heat exchange and also minimizes the bonding phenomena between the grains.
  • the first method according to the invention is further characterized in that it essentially comprises the following steps: - drying the resin,
  • drying can be carried out by passing the granules through a flow of dry air (dew point below -35 ° C) and warm air (around 175 ° C) for a period which generally varies between 4 a.m. and 6 a.m.
  • drying is carried out until a residual water content of less than 20 ppm is obtained.
  • the heating is carried out at a temperature between 275 ° C and 285 ° C. This melts the resin, the melting point of which is around 245 ° C to 255 ° C. It is important not to exceed this temperature, in order to limit the production of decomposition products such as acetaldehyde.
  • the plasticization-fusion takes place in a sheath regulated in temperature around 280 ° C in which turns an endless screw with constant pitch or with a leakage thread.
  • the worm has a compression ratio, that is to say a ratio between the surface, in section, of entry of the screw and the surface, in section, of exit of the screw, which is between 2 , 5 and 3, preferably around 2.7.
  • the preform obtained is also characterized in that it is composed of material having a crystallinity or a crystallinity rate of less than 10%, preferably less than 5%, and good transparency, similar to the characteristics of crystallinity and transparency of the preforms. obtained with polyesters of intrinsic viscosity greater than 0.65 dl / g.
  • a non-return valve is attached to the end of said worm and in some cases, a rear cylinder can be provided to allow the screw to move back when it plasticizes and to advance when there is injection or transfer of material molten.
  • a conventional hot block is used for the transfer of the melt.
  • the nozzle (s) and the obturator (s) are heated to a temperature of between 260 ° C. and 275 C.
  • the process for manufacturing the preform is further characterized in that the injection pressure of the resin melted in the mold (s) is between 2.5.10 7 Pa (250 bars) and 5.10 7 Pa (500 bars) for a temperature between 260 ° C and 275 ° C.
  • the pressure values represent about half of those used in a conventional process using a high VI resin, i.e. on the order of 0.72 dl / g to 0.83 dl / g or more. It therefore results also significant savings at this level, both in terms of the necessary installations or their maintenance, as well as in terms of energy consumption.
  • the cooling step it has been found to be particularly advantageous for the mold or molds to be cooled to a temperature of between 0 ° C. and 10 ° C. This can be achieved by all the cooling methods and devices available to those skilled in the art.
  • the period commonly known as the "holding period" during which the shrinkage of the plastic material is compensated for which solidifies by injection of additional plastic material at constant pressure lasts approximately 6 seconds.
  • the PET resin preform capable of being obtained by implementing the above method is characterized in that the intrinsic viscosity (VI) of the polyester forming the walls of said preform is between 0.45 dl / g and 0.65 dl / g.
  • the present invention also relates to a process for manufacturing PET resin containers, such as bottles for food use, from a preform according to the present invention or obtained according to the first process according to the invention, characterized in that that it includes the steps of:
  • blowing the pre-blown preform by injecting a pressurized gas at a second higher pressure for a second period
  • the blowing or two-stretch installation can be chosen from the installations commonly used for this type of application.
  • such an installation may essentially comprise a supply of preforms, for example produced in the form of guide rails by which the preforms are brought, a device for thermal conditioning of said preforms, such as a set of '' radiant elements, at least one metal mold for blowing or bi-stretching proper by injection of a suitable gas such as, for example, compressed air, and a device for ejecting the blown product or products obtained.
  • the preform heating temperature is between 80 ° C and 100 ° C, which corresponds to a gain of about 20 ° C compared to a conventional preform.
  • this heating can be carried out by any suitable means and preferably by an enclosure or an oven provided with a set of lamps with short infrared rays directed towards the external surfaces of the preforms to be heated.
  • the temperatures indicated are those measured at the outlet of the oven and correspond to an average, longitudinal temperature gradients being sought on the walls of the heated preforms.
  • the pre-blowing of the preform takes place at a first pressure of between 1.10 5 Pa and 10.10 5 Pa (1 bar and 10 bars) during a first period of between 0.15 and 0.6 seconds.
  • the blowing of the pre-blown preform takes place at a second pressure of between 3.10 6 Pa and 4.10 6 Pa (30 bars and 40 bars) for a second period of between 0.8 seconds and 2 seconds.
  • a rod or stretching rod can also be introduced into the preform during the pre-blowing and / or blowing operations, this in order to initiate said operations and to check their proper progress.
  • the invention also relates to a PET container, characterized in that it is composed of a resin with an intrinsic viscosity of less than 0.65 dl / g.
  • the invention also relates to a PET container obtained from a preform according to the invention or capable of being obtained by implementing the second method previously described, characterized in that the intrinsic viscosity (VI) of the polyester forming the walls of said container is between 0.45 dl / g and 0.65 dl / g.
  • said container is further characterized in that the density of the polyester forming the walls of said container is between 1.36 and 1.37.
  • the average crystallinity of the polyester forming the walls of said container is between 25% and 35%.
  • the container according to the invention can have all the shapes and sizes normally encountered in the industry.
  • the container according to the invention is also characterized in that its permeability to carbon dioxide is improved by at least 5% by compared to that of a container obtained with a PET resin of intrinsic viscosity (VI) greater than or equal to 0.65 dl / g.
  • VI intrinsic viscosity
  • permeabilities given as examples in the table of the present description are measured according to a test carried out on "Mocon Permatran C4 / 40". In this test, duplicate bottle samples are prepared. The samples are prepared according to a precise 2 to 2 offset program to present the same C0 2 saturation time. The carbonation of the bottles is done according to the classic chemical carbonation method. The actual test is carried out as follows:
  • the invention further relates to a third method for manufacturing PET containers according to the invention, in particular for food bottles, characterized in that it essentially comprises the steps consisting in: - manufacturing a preform from a PET resin by implementing the first method according to the invention and / or using a preform according to the invention and,
  • the present invention also relates to a PET food container, in particular a food bottle, preferably a food bottle intended to contain water, obtained, where appropriate, with the abovementioned manufacturing methods.
  • the water or the water-based liquids contained in said container or said bottle can be, by way of nonlimiting examples, still or sparkling water, mineral water, spring water, treated water (purified, sterilized, supplemented with minerals, flavored ...), carbonated drinks ("sodas”), fruit juices, milk and the like.
  • the copolymer 1 is a copolymer according to the state of the art while the copolymers 2 to 6 are used in accordance with the present invention.
  • polyesters were used for the manufacture of a 50 cl bottle according to the process below:
  • the polyester granules are melted in an endless monovis whose barrel temperature is 285 ° C.
  • the molten polyester is fed into a preform injection device sold under the name "HUSKY 48 imprint XL 300 press" with an injection temperature between 262 ° C and 266 ° C and a pressure of 450 bars.
  • the preforms are cooled by circulation of water to obtain a temperature of 8.5 ° C.
  • the overall cycle time for injection is 15.7 s.
  • the preforms After the preforms have cooled, the latter are fed into a blowing installation for the production of bottles with a capacity of 0.5 1 having a neck with a shape referenced by the standardized designation 28 PCO and a bottom with a petaloid shape with 5 petals.
  • This installation is marketed under the name "SIDEL SBO 1 F2 LAB”.
  • the preforms are heated to a temperature of 87 ° C.
  • Meadow- blowing is carried out for 0.19 s under a blowing pressure of 8.5 bars while blowing is carried out for 1.78 s under a blowing pressure of 38 bars.
  • the speed of the drawing rod is 1.2 m / s.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)

Abstract

The invention concerns the field of manufacture of PET containers designed in particular for packaging food products, particularly bottles for aerated beverages such as in particular natural and mineral water. The invention provides a method for manufacturing PET resin preforms and the resulting preforms, a method for making PET resin containers from said preforms and the manufactured containers, in particular food bottles made of PET resin. The method for making PET resin preforms is characterised in that it consists in using a PET resin having an intrinsic viscosity (IV) less than 0.65 dl/g.

Description

Procédés de fabrication de préformes et de contenants en PET tels que des bouteilles alimentaires, contenants et préformes intermédiaires obtenus Processes for manufacturing PET preforms and containers such as food bottles, containers and intermediate preforms obtained
La présente invention concerne le domaine des matériaux synthétiques communément appelés matières plastiques et leurs transformations en vue de la fabrication de produits d'emballage ou de conditionnement. L'invention concerne particulièrement le domaine de la fabrication de contenants en polyester destinés à un usage alimentaire tels que des bouteilles, notamment des bouteilles destinées à contenir de l'eau.The present invention relates to the field of synthetic materials commonly called plastics and their transformation for the production of packaging or packaging products. The invention particularly relates to the field of the manufacture of polyester containers intended for food use such as bottles, in particular bottles intended to contain water.
Les polyesters et notamment le polyéthylène téréphtalate (PET) et ses copolymères sont bien connus pour la fabrication de toutes sortes de matériaux d'emballage ou de conditionnement, tels que, par exemple, des bouteilles, bidons, boîtes, films, sacs, etc.Polyesters and in particular polyethylene terephthalate (PET) and its copolymers are well known for the manufacture of all kinds of packaging or packaging materials, such as, for example, bottles, cans, boxes, films, bags, etc.
En particulier dans le domaine alimentaire, le PET et ses dérivés sont largement utilisés dans la fabrication de bouteilles, notamment des bouteilles destinées à contenir de l'eau, plate ou gazeuse, des jus de fruits, etc. Actuellement, les polymères de PET utilisés dans la production de bouteilles à usage alimentaire présentent des propriétés d'emploi, notamment un effet dit « de barrière » aux différents gaz (vapeur d'eau, oxygène, dioxyde de carbone...) qui augmentent avec la viscosité intrinsèque (VI) du matériau employé, c'est-à-dire avec la longueur des chaînes des polymères mis en œuvre.In particular in the food sector, PET and its derivatives are widely used in the manufacture of bottles, in particular bottles intended to contain water, still or sparkling, fruit juices, etc. Currently, the PET polymers used in the production of bottles for food use have employment properties, in particular a so-called “barrier” effect to the various gases (water vapor, oxygen, carbon dioxide, etc.) which increase with the intrinsic viscosity (VI) of the material used, that is to say with the length of the chains of the polymers used.
De ce fait, les matériaux présentant de bonnes propriétés d'imperméabilité gazeuse sont généralement visqueux (VI comprise entre 0,72 dl/g et 0,83 dl/g), donc difficiles à mettre en œuvre industriellement et onéreux à produire et à utiliser. De plus, lors de la transformation de ces matériaux, des quantités relativement importantes d' acétaldéhyde se forment, ce qui constitue un problème supplémentaire lorsque les bouteilles réalisées sont prévues pour contenir certaines boissons, par exemple de l'eau minérale. En effet, même des quantités infimes d' acétaldéhyde (de l'ordre de 20 ppm) dans le matériau formant la bouteille suffisent à donner un goût fruité non souhaité aux boissons qui y sont contenues.Therefore, materials with good gas impermeability properties are generally viscous (VI between 0.72 dl / g and 0.83 dl / g), therefore difficult to implement industrially and expensive to produce and use . In addition, during the processing of these materials, relatively large amounts of acetaldehyde are formed, which constitutes an additional problem when the bottles produced are intended to contain certain drinks, for example mineral water. Indeed, even minute quantities of acetaldehyde (of the order of 20 ppm) in the material forming the bottle are enough to give an undesired fruity taste to the drinks contained therein.
Par ailleurs, les procédés de fabrication de PET de degré de polymérisation élevé existants impliquent la présence d'une étape de polymérisation ou de postcondensation en phase solide (PC S ou SSP pour Solid State Polymerization en anglais) rendant le procédé plus cher et plus compliqué.Furthermore, the existing methods for manufacturing PET with a high degree of polymerization imply the presence of a step of solid phase polymerization or postcondensation (PC S or SSP for Solid State Polymerization in English) making the process more expensive and more complicated.
Pour tenter de résoudre les problèmes rencontrés, différentes solutions ont déjà été envisagées et, pour certaines, mises en œuvre.In an attempt to resolve the problems encountered, various solutions have already been envisaged and, for some, implemented.
Le problème posé par la présente invention consiste, par conséquent, à pallier les inconvénients précités et à proposer un procédé de fabrication de préformes et de contenants en PET ne nécessitant pas d'étape de SSP tout en garantissant l'obtention de contenants dont les propriétés physiques et chimiques sont conformes aux exigences actuelles ou à venir. La présente invention a pour objet un premier procédé de fabrication de préformes en résine PET ainsi que les préformes obtenues par la mise en œuvre dudit procédé.The problem posed by the present invention therefore consists in overcoming the aforementioned drawbacks and in proposing a process for manufacturing preforms and PET containers which does not require an SSP step while guaranteeing the obtaining of containers whose properties physical and chemical meet current or future requirements. The present invention relates to a first method for manufacturing PET resin preforms as well as the preforms obtained by the implementation of said method.
En effet, dans le domaine de la fabrication de contenants, les résines synthétiques employées sont habituellement transformées par injection et moulage en préformes, c'est-à-dire en des corps creux sensiblement en forme de tubes (éventuellement munis à leurs extrémités ouvertes de cols de bouteilles) pour ensuite être soufflées ou biétirées lors de la fabrication du contenant proprement dit. La présente invention a encore pour objet un second procédé de fabrication de contenants en résine PET, tels que des bouteilles à usage alimentaire, à partir des préformes précitées ainsi que lesdits contenants en PET qui en résultent.In fact, in the field of container manufacturing, the synthetic resins used are usually transformed by injection and molding into preforms, that is to say into hollow bodies substantially in the form of tubes (possibly provided at their open ends with bottle necks) to then be blown or stretched during the manufacturing of the container itself. The present invention also relates to a second method of manufacturing PET resin containers, such as bottles for food use, from the aforementioned preforms as well as said PET containers which result therefrom.
Enfin, la présente invention a, en outre, pour objet un contenant en PET, notamment un contenant alimentaire, en particulier une bouteille alimentaire, de préférence une bouteille alimentaire destinée à contenir de l'eau ainsi qu'un troisième procédé de fabrication de contenants en PET regroupant les premier et second procédés séparés précédemment évoqués.Finally, the present invention further relates to a PET container, in particular a food container, in particular a food bottle, preferably a food bottle intended to contain water, as well as a third method of manufacturing containers. in PET combining the first and second separate processes previously mentioned.
Le procédé de fabrication de préformes en résine PET selon l'invention est caractérisé en ce qu'il consiste à utiliser une résine PET de viscosité intrinsèque (VI) inférieure à 0,65 dl/g.The process for manufacturing PET resin preforms according to the invention is characterized in that it consists in using a PET resin with an intrinsic viscosity (VI) of less than 0.65 dl / g.
La préforme susceptible d'être obtenue par la mise en œuvre de ce premier procédé est caractérisée en ce que la viscosité intrinsèque (VI) du polyester formant les parois de ladite préforme est comprise entre 0,45 dl/g et 0,65 dl/g.The preform capable of being obtained by the implementation of this first process is characterized in that the intrinsic viscosity (VI) of the polyester forming the walls of said preform is between 0.45 dl / g and 0.65 dl / g.
Le second procédé de fabrication de contenants en résine PET, tels que des bouteilles à usage alimentaire à partir d'une préforme selon l' invention ou obtenue par la mise en œuvre du premier procédé selon l'invention, est caractérisé en ce qu'il comprend essentiellement les étapes consistant à :The second method of manufacturing PET resin containers, such as bottles for food use from a preform according to the invention or obtained by implementing the first method according to the invention, is characterized in that it essentially comprises the steps consisting in:
- introduire la préforme dans une installation de soufflage ou de biétirage comportant notamment un dispositif de chauffage,- introduce the preform into a blowing or two-stretch installation comprising in particular a heating device,
- chauffer la préforme,- heat the preform,
- pré-souffler la préforme chauffée par injection d'un gaz sous pression à une première pression pendant une première période,- pre-blowing the preform heated by injecting a gas under pressure at a first pressure during a first period,
- souffler la préforme pré-soufflée par injection d'un gaz sous pression à une seconde pression plus élevée pendant une seconde période, etblowing the pre-blown preform by injecting a pressurized gas at a second higher pressure for a second period, and
- éjecter le contenant obtenu.- eject the container obtained.
Le troisième procédé de fabrication de contenants en PET selon l'invention, notamment de bouteilles alimentaires, est caractérisé en ce qu'il comprend essentiellement les étapes consistant à : - fabriquer une préforme à partir de ladite résine PET grâce à la mise en œuvre du premier procédé selon l'invention et/ou utiliser une pré forme selon l'invention et,The third method of manufacturing PET containers according to the invention, in particular food bottles, is characterized in that it essentially comprises the steps consisting in: - manufacturing a preform from said PET resin thanks to the implementation of the first method according to the invention and / or use a preform according to the invention and,
- fabriquer, à partir de la préforme précédemment obtenue, ledit contenant grâce à la mise en œuvre du second procédé selon l'invention. Le contenant en PET obtenu à partir d'une préforme selon la présente invention ou susceptible d'être obtenu par la mise en œuvre du second procédé ci-dessus est caractérisé en ce que la viscosité intrinsèque (VI) du polyester formant les parois dudit contenant est comprise entre 0,45 dl/g et 0,65 dl/g. L'invention sera mieux comprise, grâce à la description ci- après, qui se rapporte à un mode de réalisation préféré, donné à titre d'exemple non limitatif.- Manufacture, from the preform previously obtained, said container through the implementation of the second method according to the invention. The PET container obtained from a preform according to the present invention or capable of being obtained by implementing the second process above is characterized in that the intrinsic viscosity (VI) of the polyester forming the walls of said container is between 0.45 dl / g and 0.65 dl / g. The invention will be better understood from the description below, which relates to a preferred embodiment, given by way of nonlimiting example.
Le procédé de fabrication de préformes en résine PET selon l'invention est caractérisé en ce qu'il consiste à utiliser une résine polyester de viscosité intrinsèque (VI) inférieure à 0,65 dl/g. L'expression « inférieure à 0,65 dl/g » signifie strictement inférieure à 0,65 dl/g.The process for manufacturing PET resin preforms according to the invention is characterized in that it consists in using a polyester resin with an intrinsic viscosity (VI) of less than 0.65 dl / g. The expression "less than 0.65 dl / g" means strictly less than 0.65 dl / g.
De manière avantageuse, la viscosité intrinsèque (VI) est comprise entre 0,45 dl/g et 0,65 dl/g.Advantageously, the intrinsic viscosity (VI) is between 0.45 dl / g and 0.65 dl / g.
Par viscosité intrinsèque (VI), on entend la viscosité d'une solution de polymère à concentration nulle. Cette valeur est calculée selon la formule (I) ci-dessous à partir de la détermination d'un indice de viscosité (IV) en dl/g mesuré sur une solution de polymère à 0,5 g de polymère /100 ml d'un solvant constitué d'orthodichlorobenzène et de phénol (50/50 en poids) à 25°C, selon la norme ISO 1628/5 du 15 juin 1986. Pour les polyesters de l'invention, la viscosité intrinsèque (VI) en dl/g est calculée par la formule (I) suivante :By intrinsic viscosity (VI) is meant the viscosity of a zero concentration polymer solution. This value is calculated according to formula (I) below from the determination of a viscosity index (IV) in dl / g measured on a polymer solution at 0.5 g of polymer / 100 ml of a solvent consisting of orthodichlorobenzene and phenol (50/50 by weight) at 25 ° C, according to ISO standard 1628/5 of June 15, 1986. For the polyesters of the invention, the intrinsic viscosity ( VI) in dl / g is calculated by the following formula (I):
VI = -10-TV2 + 0,94ιV + 0,0122 (I)VI = -10-TV 2 + 0.94ιV + 0.0122 (I)
Grâce au procédé de la présente invention, il devient possible de s'affranchir de l'étape de PCS ou SSP présente dans les procédés connus et notamment employée pour augmenter la viscosité intrinsèque (VI). Cette suppression apporte des gains significatifs en énergie, en matériel ainsi qu'en temps, sachant que l'étape de postcondensation en phase solide se déroule généralement à plus de 200°C sous un flux d'azote et peut durer de 10 heures à 30 heures. La présente invention permet non seulement des gains de productivité et des économies de matières substantielles au niveau industriel, mais également l'obtention d'un produit final aux caractéristiques techniques équivalentes à celles des produits existants voire supérieures, comme démontré ci-après. Les résines PET convenant à la mise en œuvre du procédé selon l'invention sont des polyesters de poly éthylène téréphtalate (PET), c'est-à- dire des polyesters saturés thermoplastiques dont le nom générique couvre toute une famille de polymères plus ou moins copolymérisés.Thanks to the process of the present invention, it becomes possible to dispense with the PCS or SSP stage present in the known processes and in particular used to increase the intrinsic viscosity (VI). This elimination brings significant gains in energy, in material as well as in time, knowing that the stage of postcondensation in solid phase generally takes place at more than 200 ° C under a flow of nitrogen and can last from 10 hours to 30 hours. The present invention not only allows productivity gains and substantial savings in materials at the industrial level, but also the obtaining of a final product with technical characteristics equivalent to those of existing or even superior products, as demonstrated below. The PET resins suitable for implementing the process according to the invention are polyesters of polyethylene terephthalate (PET), that is to say saturated thermoplastic polyesters whose generic name covers a whole family of polymers more or less copolymerized.
Les monomères préférés sont l'acide téréphtalique et l'éthylène glycol conduisant au polyéthylènetéréphtalate plus connu sous l'abréviation PET comme indiqué ci-dessus.The preferred monomers are terephthalic acid and ethylene glycol leading to polyethylene terephthalate better known under the abbreviation PET as indicated above.
Dans le présent document le terme PET couvre aussi bien un homopolymère obtenu uniquement à partir de monomères acide téréphtalique ou ses esters comme le diméthyltéréphtalate et monomères éthylène glycol que des copolymères comprenant au moins 92,5 % en nombre d'unités récurrentes d'éthylènetéréphtalate.In the present document, the term PET covers both a homopolymer obtained solely from monomers of terephthalic acid or its esters such as dimethyl terephthalate and ethylene glycol monomers as well as copolymers comprising at least 92.5% by number of repeating units of ethylene terephthalate.
Selon une caractéristique de l'invention, le polyester comprend au moins un retardateur de cristallisation permettant, notamment au cours du refroidissement de l'article moulé ou injecté tel qu'une préforme, de ralentir ou retarder la cristallisation du polyester pour ainsi obtenir une cristallisation en cristaux de taille très petite en évitant la cristallisation sphérolitique et de pouvoir fabriquer un article transparent, dont les parois ne présentent pas de voile ou "haze", avec des propriétés mécaniques acceptables.According to a characteristic of the invention, the polyester comprises at least one crystallization retarder allowing, in particular during the cooling of the molded or injected article such as a preform, to slow down or delay the crystallization of the polyester so as to obtain crystallization in very small crystals avoiding spherulitic crystallization and being able to manufacture a transparent article, the walls of which do not have haze or "haze", with acceptable mechanical properties.
Ces agents retardateurs de cristallisation sont des composés difonctionnels tels que des diacides et ou diols ajoutés au mélange de monomères avant ou au cours de la polymérisation du polyester.These crystallization retarding agents are difunctional compounds such as diacids and or diols added to the mixture of monomers before or during the polymerization of the polyester.
Comme agent retardateur de cristallisation, on peut citer à titre d'exemples de diacides, l'acide isophtalique, l'acide naphtalènedicarboxylique, l'acide cyclohexane dicarboxylique, l'acide cyclohexane diacétique, l'acide succinique, l'acide glutarique, l'acide adipique, l'acide azélaïque, l'acide sébacique et à titre d'exemples de diols, on peut citer les diols aliphatiques comprenant de 3 à 20 atomes de carbone, les diols cycloaliphatiques de 6 à 20 atomes de carbone, les diols aromatiques comprenant de 6 à 14 atomes de carbone et leurs mélanges comme le di-éthylène glycol, le tri-éthylène glycol, les isomères du 1,4- cyclohexane di-méthanol, le 1,3-propane diol, le 1,4-butane diol, le 1,5- pentane diol, le (2,4)-3 méthylpentanediol, le (l,4)-2 méthylpentanediol, le (l,3)-2,2,4-triméthylpentanediol, le (l,3)-2-éthylhexanediol, le (l,3)-2,2- diéthylpropanediol, le 1,3-hexanediol, le l,4-di(hydroxyéthoxy)benzène, le 2,2-bis(4-hydroxycyclohexyl)propane, le 2,4-dihydroxy-l, 1,3,3- tétraméthylcyclobutane, le 2,2-bis(3-hydroxyéthoxyphényl)propane, le 2,2- bis(4-hydroxypropoxyphényl)propane et leurs mélanges.Mention may be made, as crystallization retarding agent, of examples of diacids, isophthalic acid, naphthalenedicarboxylic acid, cyclohexane dicarboxylic acid, cyclohexane diacetic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid and as examples of diols, there may be mentioned aliphatic diols comprising from 3 to 20 carbon atoms, cycloaliphatic diols from 6 to 20 carbon atoms, diols aromatics comprising from 6 to 14 carbon atoms and their mixtures such as di-ethylene glycol, tri-ethylene glycol, isomers of 1,4-cyclohexane di-methanol, 1,3-propane diol, 1,4- butane diol, 1,5-pentane diol, (2,4) -3 methylpentanediol, (1,4) -2 methylpentanediol, (1,3) -2,2,4-trimethylpentanediol, (l, 3) -2-ethylhexanediol, (1,3) -2,2-diethylpropanediol, 1,3-hexanediol, 1,4-di (hydroxyethoxy) benzene, 2,2-bis (4-hydroxycyclohexyl) propane , 2,4-di hydroxy-1,1,3,3-tetramethylcyclobutane, 2,2-bis (3-hydroxyethoxyphenyl) propane, 2,2-bis (4-hydroxypropoxyphenyl) propane and mixtures thereof.
Le diéthylène glycol est souvent présent dans les polyesters de manière inhérente car il se forme pendant la synthèse par condensation de deux molécules d'éthylène glycol. Selon la concentration désirée en unités récurrentes comprenant un reste de diéthylène glycol (DEG) dans le polyester final, soit du diéthylène glycol est ajouté aux mélanges de monomères, soit les conditions de synthèse du polyester sont contrôlées pour limiter la formation de diéthylène glycol. Avantageusement, la concentration molaire en diéthylène glycol dans le polyester par rapport aux nombres de moles de monomères diacides est inférieure à 3,5 %, de préférence inférieure à 2 % molaire.Diethylene glycol is often present in polyesters inherently because it is formed during the synthesis by condensation of two molecules of ethylene glycol. Depending on the desired concentration in repeating units comprising a residue of diethylene glycol (DEG) in the final polyester, either diethylene glycol is added to the monomer mixtures, or the polyester synthesis conditions are controlled to limit the formation of diethylene glycol. Advantageously, the molar concentration of diethylene glycol in the polyester relative to the numbers of moles of diacid monomers is less than 3.5%, preferably less than 2 mol%.
Concernant les autres retardateurs de cristallisation, la concentration molaire par rapport au nombre de moles de la totalité des diacides dans le mélange de monomères et donc dans le polyester obtenu est avantageusement inférieure à 7,5 %, avec comme condition que la teneur en DEG doit être déduite de cette valeur s'il est présent. En d'autres termes, la concentration molaire totale en retardateur de cristallisation doit être inférieure à 7,5 % comme cela est indiqué dans le brevet européen n° 41035.As regards the other crystallization retarders, the molar concentration relative to the number of moles of all of the diacids in the mixture of monomers and therefore in the polyester obtained is advantageously less than 7.5%, with the condition that the DEG content must be deducted from this value if it is present. In other words, the total molar concentration of crystallization retardant must be less than 7.5% as indicated in European Patent No. 41035.
Bien entendu, le polyester peut comprendre un mélange d'agents retardateurs de cristallisation de type acide et/ou diol.Of course, the polyester may comprise a mixture of agents for retarding crystallization of the acid and / or diol type.
Si les procédés d'injection de préformes et de soufflage des contenants creux permettent de contrôler notamment les vitesses de refroidissement pour éviter la cristallisation sphérolitique de la résine ou dans le cas où les bouteilles à produire ne seraient pas translucides telles que les bouteilles de lait par exemple, la concentration totale en retardateur de cristallisation peut être très faible, par exemple de l'ordre de 1 %, voire nulle à l'exception du DEG formé au cours de la synthèse du polyester.If the processes for injecting preforms and blowing hollow containers make it possible to control in particular the cooling rates to avoid spherulitic crystallization of the resin or in the case where the bottles to be produced are not translucent such as milk bottles by For example, the total concentration of crystallization retarder can be very low, for example of the order of 1%, or even zero with the exception of the DEG formed during the synthesis of the polyester.
Selon un mode de réalisation de l'invention, le polyester de l'invention comprend avantageusement moins de 4 % d'acide isophtalique et moins de 4 % de diéthylène glycol, teneur exprimée en % de moles de retardateur de cristallisation par rapport au nombre de moles de la totalité des monomères diacides. Selon un mode de réalisation préféré, le ledit polyester ne contient pas de retardateur de cristallisation mais toutefois, il contient du DEG provenant de la fabrication dudit polyester. Les grandes étapes de la synthèse d'une telle résine sont les suivantes. Tout d'abord, on réalise un « empâtage » c'est-à-dire un mélange des diacides sous forme de poudres avec les glycols liquides. Le mélange est ensuite estérifié de façon classique par chauffage et extraction simultanée de l'eau formée. La polymérisation proprement dite s'effectue en chauffant sous vide le mélange réactiormel à une température comprise entre environ 260°C et 280°C en extrayant du glycol, ladite polymérisation pouvant être précédée d'une première étape de prépolymérisation dans des conditions similaires. On arrête la réaction lorsque l'on obtient un mélange visqueux ayant une apparence de miel ou de mélasse. Ce mélange visqueux peut ensuite être passé dans une filière à joncs connue en soi. Les joncs obtenus sont alors plongés dans un bac d'eau de refroidissement et ensuite découpés dans une granulatrice pour obtenir de petits granulés solides, par exemple sous la forme de cubes de 2 mm à 3 mm de côté. Les granulés de résine PET obtenus sont amorphes et transparents. Afin de pouvoir utiliser la résine précédemment synthétisée dans des applications industrielles, il peut encore être nécessaire de la cristalliser. A cette fin, la présente invention prévoit un procédé de cristallisation sphérolitique de la résine PET caractérisé en ce qu'il consiste à chauffer la résine à une température comprise entre 120°C et 200°C.According to one embodiment of the invention, the polyester of the invention advantageously comprises less than 4% of isophthalic acid and less than 4% of diethylene glycol, content expressed in% of moles of crystallization retarder relative to the number of moles of all of the diacid monomers. According to a preferred embodiment, the said polyester does not contain a retardation of crystallization but however, it contains DEG coming from the manufacture of the said polyester. The main steps in the synthesis of such a resin are as follows. First of all, a "pasting" is carried out, that is to say a mixture of the diacids in the form of powders with the liquid glycols. The mixture is then esterified in a conventional manner by heating and simultaneous extraction of the water formed. The actual polymerization is carried out by heating the reaction mixture under vacuum to a temperature of between approximately 260 ° C. and 280 ° C. by extracting glycol, said polymerization possibly being preceded by a first prepolymerization step under similar conditions. The reaction is stopped when a viscous mixture having the appearance of honey or molasses is obtained. This viscous mixture can then be passed through a rod ring known per se. The rods obtained are then immersed in a tank of cooling water and then cut out in a granulator to obtain small solid granules, for example in the form of cubes of 2 mm to 3 mm on a side. The PET resin granules obtained are amorphous and transparent. In order to be able to use the resin previously synthesized in industrial applications, it may still be necessary to crystallize it. To this end, the present invention provides a process for spherolitic crystallization of the PET resin, characterized in that it consists in heating the resin to a temperature between 120 ° C and 200 ° C.
Selon une variante particulièrement intéressante, la cristallisation sphérolitique est réalisée sous agitation afin d'éviter le collage entre les granulés. Les granulés amorphes transparents et collants sont ainsi transformés en granulés cristallisés blancs opaques (aspect laiteux) qui ne collent plus entre eux et qui présentent une viscosité intrinsèque (VI) inférieure à 0,65 dl/g, de préférence comprise entre 0,45 dl/g et 0,65 dl/g. De manière préférée, la cristallisation sphérolitique est réalisée dans un lit fiuidisé. Ceci permet d'assurer un meilleur échange thermique et minimise également les phénomènes de collage entre les grains.According to a particularly advantageous variant, the spherulitic crystallization is carried out with stirring in order to avoid sticking between the granules. The transparent and sticky amorphous granules are thus transformed into opaque white crystallized granules (milky appearance) which no longer stick to each other and which have an intrinsic viscosity (VI) of less than 0.65 dl / g, preferably between 0.45 dl / g and 0.65 dl / g. Preferably, the spherulitic crystallization is carried out in a fluidized bed. This ensures better heat exchange and also minimizes the bonding phenomena between the grains.
Le premier procédé selon l'invention est encore caractérisé en ce qu'il comprend essentiellement les étapes suivantes : - sécher la résine,The first method according to the invention is further characterized in that it essentially comprises the following steps: - drying the resin,
- fondre la résine par chauffage dans un fourreau de plastification notamment muni d'une vis sans fin,- melting the resin by heating in a plastic sheath, in particular provided with an endless screw,
- transférer la résine fondue du fourreau vers un distributeur ou bloc chaud muni d'au moins une busette et d'au moins un obturateur chauffés,- transfer the molten resin from the sheath to a distributor or hot block provided with at least one heated nozzle and at least one obturator,
- injecter la résine fondue dans au moins un moule de la préforme que l'on souhaite obtenir,- inject the molten resin into at least one mold of the preform that one wishes to obtain,
- compenser le retrait de la matière injectée par injection additionnelle de résine fondue au fur et à mesure que la préforme se forme dans le ou les moules lors du refroidissement de la résine injectée, etcompensate for the shrinkage of the injected material by additional injection of molten resin as the preform is formed in the mold (s) during the cooling of the injected resin, and
- éjecter la préforme fabriquée du ou des moules et la laisser refroidir à l'extérieur.- eject the manufactured preform from the mold (s) and allow it to cool outside.
A titre d'exemple non limitatif, le séchage peut être effectué en faisant passer les granulés dans un flux d'air sec (point de rosée inférieur à - 35°C) et chaud (environ 175°C) pendant une durée qui varie généralement entre 4 heures et 6 heures.By way of nonlimiting example, drying can be carried out by passing the granules through a flow of dry air (dew point below -35 ° C) and warm air (around 175 ° C) for a period which generally varies between 4 a.m. and 6 a.m.
Selon une caractéristique de l'invention, le séchage se fait jusqu'à l'obtention d'une teneur résiduelle en eau inférieure à 20 ppm.According to a characteristic of the invention, drying is carried out until a residual water content of less than 20 ppm is obtained.
Selon une autre caractéristique le chauffage est réalisé à une température comprise entre 275°C et 285°C. Ceci permet de fondre la résine dont le point de fusion se situe aux alentours de 245°C à 255°C. Il est important de ne pas dépasser cette température, ce afin de limiter la production de produits de décomposition comme l' acétaldéhyde.According to another characteristic, the heating is carried out at a temperature between 275 ° C and 285 ° C. This melts the resin, the melting point of which is around 245 ° C to 255 ° C. It is important not to exceed this temperature, in order to limit the production of decomposition products such as acetaldehyde.
La plastification-fusion se déroule dans un fourreau régulé en température vers 280°C dans lequel tourne une vis sans fin à pas constant ou à filet de fuite. La vis sans fin possède un taux de compression, c'est-à- dire un rapport entre la surface, en section, d'entrée de la vis et la surface, en section, de sortie de la vis, qui est compris entre 2,5 et 3, de préférence de l'ordre de 2,7.The plasticization-fusion takes place in a sheath regulated in temperature around 280 ° C in which turns an endless screw with constant pitch or with a leakage thread. The worm has a compression ratio, that is to say a ratio between the surface, in section, of entry of the screw and the surface, in section, of exit of the screw, which is between 2 , 5 and 3, preferably around 2.7.
Ceci permet d'éviter ou pour le moins de minimiser la pénétration dans le mélange de polymères fondu de bulles d'air extérieur susceptibles d'entraîner la formation de cavités dans le produit extrudé ou moulé final. Cette plage permet également de minimiser les phénomènes de cisaillement qui ont pour conséquence des échauffements locaux pouvant dépasser 300°C et qui sont par conséquent générateurs de produits de décomposition, dont l'acétaldéhyde.This makes it possible to avoid or at the very least minimize the penetration into the mixture of molten polymers of bubbles of outside air capable of causing the formation of cavities in the final extruded or molded product. This range also makes it possible to minimize the shearing phenomena which result in local heating which may exceed 300 ° C. and which consequently generate decomposition products, including acetaldehyde.
La préforme obtenue est également caractérisée en ce qu'elle est composée de matière possédant une cristallinité ou un taux de cristallinité inférieur à 10%, de préférence inférieur à 5%, et une bonne transparence, similaires aux caractéristiques de cristallinité et de transparence des préformes obtenues avec des polyesters de viscosité intrinsèque supérieure à 0,65 dl/g.The preform obtained is also characterized in that it is composed of material having a crystallinity or a crystallinity rate of less than 10%, preferably less than 5%, and good transparency, similar to the characteristics of crystallinity and transparency of the preforms. obtained with polyesters of intrinsic viscosity greater than 0.65 dl / g.
Un clapet anti-retour est fixé à l'extrémité de ladite vis sans fin et dans certains cas, un vérin arrière peut être prévu pour permettre à la vis de reculer quand elle plastifie et d'avancer quand il y a injection ou transfert de matière fondue.A non-return valve is attached to the end of said worm and in some cases, a rear cylinder can be provided to allow the screw to move back when it plasticizes and to advance when there is injection or transfer of material molten.
Pour le transfert de la matière fondue on utilise un bloc chaud conventionnel. Selon une autre caractéristique, la ou les busettes et le ou les obturateurs sont chauffés à une température comprise entre 260°C et 275 C. Par ailleurs, le procédé de fabrication de la préforme est encore caractérisé en ce que la pression d'injection de la résine fondue dans le ou les moules est comprise entre 2,5.107 Pa (250 bars) et 5.107 Pa (500 bars) pour une température comprise entre 260°C et 275°C. Ces faibles valeurs de température et de pression permettent également de minimiser la production d'acétaldéhyde. Les valeurs de pression représentent environ la moitié de celles employées dans un procédé classique utilisant une résine à VI élevée, c'est- à-dire de l'ordre de 0,72 dl/g à 0,83 dl/g ou plus. Il en résulte donc également des économies importantes à ce niveau, aussi bien en ce qui concerne les installations nécessaires ou leur entretien, qu'en ce qui concerne la consommation d'énergie.For the transfer of the melt, a conventional hot block is used. According to another characteristic, the nozzle (s) and the obturator (s) are heated to a temperature of between 260 ° C. and 275 C. Furthermore, the process for manufacturing the preform is further characterized in that the injection pressure of the resin melted in the mold (s) is between 2.5.10 7 Pa (250 bars) and 5.10 7 Pa (500 bars) for a temperature between 260 ° C and 275 ° C. These low values of temperature and pressure also make it possible to minimize the production of acetaldehyde. The pressure values represent about half of those used in a conventional process using a high VI resin, i.e. on the order of 0.72 dl / g to 0.83 dl / g or more. It therefore results also significant savings at this level, both in terms of the necessary installations or their maintenance, as well as in terms of energy consumption.
Pour ce qui est de l'étape de refroidissement, il s'est avéré particulièrement avantageux que le ou les moules soient refroidis à une température comprise entre 0°C et 10°C. Ceci peut être réalisé par tous les procédés et dispositifs de refroidissement à la disposition de l'homme du métier.With regard to the cooling step, it has been found to be particularly advantageous for the mold or molds to be cooled to a temperature of between 0 ° C. and 10 ° C. This can be achieved by all the cooling methods and devices available to those skilled in the art.
La période communément appelée « période de maintien » pendant laquelle on compense le retrait du matériau plastique qui se solidifie par injection de matière plastique supplémentaire à pression constante dure environ 6 secondes.The period commonly known as the "holding period" during which the shrinkage of the plastic material is compensated for which solidifies by injection of additional plastic material at constant pressure lasts approximately 6 seconds.
La préforme en résine PET susceptible d'être obtenue par la mise en œuvre du procédé précité est caractérisée en ce que la viscosité intrinsèque (VI) du polyester formant les parois de ladite préforme est comprise entre 0,45 dl/g et 0,65 dl/g.The PET resin preform capable of being obtained by implementing the above method is characterized in that the intrinsic viscosity (VI) of the polyester forming the walls of said preform is between 0.45 dl / g and 0.65 dl / g.
La présente invention a également pour objet un procédé de fabrication de contenants en résine PET, tels que des bouteilles à usage alimentaire, à partir d'une préforme conforme à la présente invention ou obtenue selon le premier procédé selon l'invention, caractérisé en ce qu'il comprend les étapes consistant à :The present invention also relates to a process for manufacturing PET resin containers, such as bottles for food use, from a preform according to the present invention or obtained according to the first process according to the invention, characterized in that that it includes the steps of:
- introduire la préforme dans une installation de soufflage ou de biétirage comportant notamment un dispositif de chauffage,- introduce the preform into a blowing or two-stretch installation comprising in particular a heating device,
- chauffer la préforme, - pré-souffler la préforme chauffée par injection d'un gaz sous pression à une première pression pendant une première période,- heating the preform, - pre-blowing the heated preform by injecting a pressurized gas at a first pressure for a first period,
- souffler la préforme pré-soufflée par injection d'un gaz sous pression à une seconde pression plus élevée pendant une seconde période, etblowing the pre-blown preform by injecting a pressurized gas at a second higher pressure for a second period, and
- éjecter le contenant obtenu. L'installation de soufflage ou de biétirage peut être choisie parmi les installations communément mises en œuvre pour ce type d'application. A titre d'exemple non limitatif, une telle installation peut comprendre essentiellement une alimentation en préformes, par exemple réalisée sous la forme de rails de guidage par lesquels les préformes sont amenées, un dispositif de conditionnement thermique desdites préformes, tel qu'un ensemble d'éléments radiants, au moins un moule métallique pour le soufflage ou biétirage proprement dits par injection d'un gaz adapté comme par exemple de l'air comprimé, et un dispositif d'éjection du ou des produits soufflés obtenus.- eject the container obtained. The blowing or two-stretch installation can be chosen from the installations commonly used for this type of application. By way of nonlimiting example, such an installation may essentially comprise a supply of preforms, for example produced in the form of guide rails by which the preforms are brought, a device for thermal conditioning of said preforms, such as a set of '' radiant elements, at least one metal mold for blowing or bi-stretching proper by injection of a suitable gas such as, for example, compressed air, and a device for ejecting the blown product or products obtained.
De manière avantageuse, la température de chauffage de la préforme est comprise entre 80°C et 100°C, ce qui correspond à un gain d'environ 20°C par rapport à une préforme classique. Comme évoqué, ce chauffage peut être réalisé par tout moyen adapté et préférentiellement par une enceinte ou un four muni d'un ensemble de lampes à rayons infrarouges courts dirigées vers les surfaces extérieures des préformes à chauffer. Les températures indiquées sont celles mesurées à la sortie du four et correspondent à une moyenne, des gradients longitudinaux de températures étant recherchés sur les parois des préformes chauffées.Advantageously, the preform heating temperature is between 80 ° C and 100 ° C, which corresponds to a gain of about 20 ° C compared to a conventional preform. As mentioned, this heating can be carried out by any suitable means and preferably by an enclosure or an oven provided with a set of lamps with short infrared rays directed towards the external surfaces of the preforms to be heated. The temperatures indicated are those measured at the outlet of the oven and correspond to an average, longitudinal temperature gradients being sought on the walls of the heated preforms.
Le pré-soufflage de la préforme a lieu à une première pression comprise entre 1.105 Pa et 10.105 Pa (1 bar et 10 bars) pendant une première période comprise entre 0,15 et 0,6 seconde. Le soufflage de la préforme pré-soufflée a lieu à une seconde pression comprise entre 3.106 Pa et 4.106 Pa (30 bars et 40 bars) pendant une seconde période comprise entre 0,8 seconde et 2 secondes. De manière connue, une tige ou canne d'étirage peut également être introduite dans la préforme pendant les opérations de pré-soufflage et/ou de soufflage, ce afin d'amorcer lesdites opérations et d'en contrôler le bon déroulement.The pre-blowing of the preform takes place at a first pressure of between 1.10 5 Pa and 10.10 5 Pa (1 bar and 10 bars) during a first period of between 0.15 and 0.6 seconds. The blowing of the pre-blown preform takes place at a second pressure of between 3.10 6 Pa and 4.10 6 Pa (30 bars and 40 bars) for a second period of between 0.8 seconds and 2 seconds. In known manner, a rod or stretching rod can also be introduced into the preform during the pre-blowing and / or blowing operations, this in order to initiate said operations and to check their proper progress.
L'invention a également pour objet un contenant en PET, caractérisé en ce qu'il est composé d'une résine de viscosité intrinsèque inférieure à 0,65 dl/g.The invention also relates to a PET container, characterized in that it is composed of a resin with an intrinsic viscosity of less than 0.65 dl / g.
L'invention a encore objet un contenant en PET obtenu à partir d'une préforme selon l'invention ou susceptible d'être obtenu par la mise en œuvre du second procédé précédemment décrit caractérisé en ce que la viscosité intrinsèque (VI) du polyester formant les parois dudit contenant est comprise entre 0,45 dl/g et 0,65 dl/g.The invention also relates to a PET container obtained from a preform according to the invention or capable of being obtained by implementing the second method previously described, characterized in that the intrinsic viscosity (VI) of the polyester forming the walls of said container is between 0.45 dl / g and 0.65 dl / g.
De façon avantageuse, ledit contenant est encore caractérisé en ce que la densité du polyester formant les parois dudit contenant est comprise entre 1,36 et 1,37.Advantageously, said container is further characterized in that the density of the polyester forming the walls of said container is between 1.36 and 1.37.
Selon une autre caractéristique, la cristallinité moyenne du polyester formant les parois dudit contenant est comprise entre 25% et 35%. Le contenant selon l'invention peut posséder toutes les formes et tailles normalement rencontrées dans l'industrie.According to another characteristic, the average crystallinity of the polyester forming the walls of said container is between 25% and 35%. The container according to the invention can have all the shapes and sizes normally encountered in the industry.
Le contenant selon l'invention est également caractérisé en ce que sa perméabilité au dioxyde de carbone est améliorée d'au moins 5% par rapport à celle d'un contenant obtenu avec une résine PET de viscosité intrinsèque (VI) supérieure ou égale à 0,65 dl/g.The container according to the invention is also characterized in that its permeability to carbon dioxide is improved by at least 5% by compared to that of a container obtained with a PET resin of intrinsic viscosity (VI) greater than or equal to 0.65 dl / g.
Les perméabilités données à titre d'exemples dans le tableau de la présente description sont mesurées selon un test effectué sur « Mocon Permatran C4/40 ». Dans ce test on prépare des échantillons de bouteilles en double. Les échantillons sont préparés suivant un programme précis en décalage 2 à 2 pour présenter le même temps de saturation en C02. La carbonatation des bouteilles se fait suivant la méthode de carbonatation chimique classique. Le test proprement dit est réalisé de la manière suivante :The permeabilities given as examples in the table of the present description are measured according to a test carried out on "Mocon Permatran C4 / 40". In this test, duplicate bottle samples are prepared. The samples are prepared according to a precise 2 to 2 offset program to present the same C0 2 saturation time. The carbonation of the bottles is done according to the classic chemical carbonation method. The actual test is carried out as follows:
Dans un premier temps, toutes les cellules sont en mode dit « idle » (sans activité). Si aucune chambre n'est branchée, on démonte les cellules et on fixe les entrées et sorties d'azote de façon similaire. Si l'entrée d'azote est branchée sur le haut de la chambre A on répète l'opération pour la chambre B. On graisse ensuite les connecteurs et on serre à la main d'un quart de tour. Les bouteilles à tester sont ensuite placées dans lesdites chambres et on graisse les joints situés sur le capot de chaque chambre avant de refermer.At first, all the cells are in so-called "idle" mode (without activity). If no chamber is connected, the cells are dismantled and the nitrogen inlets and outlets are fixed similarly. If the nitrogen inlet is connected to the top of chamber A, repeat the operation for chamber B. Then grease the connectors and tighten by hand a quarter of a turn. The bottles to be tested are then placed in said chambers and the seals located on the hood of each chamber are greased before closing.
Il est nécessaire pour une cellule de boucher l'entrée et la sortie de dioxyde de carbone. Pour l'autre cellule, il faut faire un pont à CO2 pour que celui-ci puisse circuler jusqu'à la référence. Pour cela on utilise un tuyau souple graissé à chaque extrémité.It is necessary for a cell to block the entry and exit of carbon dioxide. For the other cell, a CO 2 bridge must be made so that it can flow to the reference. For this we use a flexible tube greased at each end.
Puis, les différentes informations relatives au test à effectuer sont saisies dans la station de travail de l'appareil de mesure. Pour de très fortes valeurs de barrières pour lesquelles la valeur d'équilibre est difficile à évaluer, il est recommandé de procéder à un test de convergence préliminaire.Then, the various information relating to the test to be carried out are entered in the work station of the measuring device. For very high barrier values for which the equilibrium value is difficult to evaluate, it is recommended to carry out a preliminary convergence test.
Ensuite le calibrage correspondant est chargé et les débits sont fixés. Le test proprement dit peut alors commencer jusqu'à l'obtention et l'affichage ou stockage des mesures enregistrées. Les conditions du test utilisé dans le cadre de la présente invention sont les suivantes :Then the corresponding calibration is loaded and the flow rates are fixed. The actual test can then start until the recorded measurements are obtained and displayed or stored. The conditions of the test used in the context of the present invention are as follows:
temps de saturation : 10 jours débit d'azote : 150 cm3 standards par minute débit de C02 : 300 cm3 standards par minute L' invention a, en outre, pour objet un troisième procédé de fabrication de contenants en PET selon l'invention, notamment de bouteilles alimentaires, caractérisé en ce qu'il comprend essentiellement les étapes consistant à : - fabriquer une préforme à partir d'une résine PET grâce à la mise en œuvre du premier procédé selon l'invention et/ou utiliser une préforme selon l'invention et,saturation time: 10 days nitrogen flow: 150 cm 3 standards per minute C0 2 flow: 300 cm 3 standards per minute The invention further relates to a third method for manufacturing PET containers according to the invention, in particular for food bottles, characterized in that it essentially comprises the steps consisting in: - manufacturing a preform from a PET resin by implementing the first method according to the invention and / or using a preform according to the invention and,
- fabriquer, à partir de la préforme précédemment obtenue, ledit contenant grâce à la mise en œuvre du second procédé selon l'invention. Finalement, la présente invention a encore pour objet un contenant alimentaire en PET, en particulier une bouteille alimentaire, de préférence une bouteille alimentaire destinée à contenir de l'eau, obtenu, le cas échéant, avec les procédés de fabrication précités.- Manufacture, from the preform previously obtained, said container through the implementation of the second method according to the invention. Finally, the present invention also relates to a PET food container, in particular a food bottle, preferably a food bottle intended to contain water, obtained, where appropriate, with the abovementioned manufacturing methods.
L'eau ou les liquides à base d'eau contenus dans ledit contenant ou ladite bouteille peuvent être, à titre d'exemples non limitatifs, de l'eau plate ou gazeuse, de l'eau minérale, de l'eau de source, de l'eau traitée (purifiée, stérilisée, supplémentée en minéraux, aromatisée...), des boissons gazeuses (« sodas »), des jus de fruits, du lait et analogues.The water or the water-based liquids contained in said container or said bottle can be, by way of nonlimiting examples, still or sparkling water, mineral water, spring water, treated water (purified, sterilized, supplemented with minerals, flavored ...), carbonated drinks ("sodas"), fruit juices, milk and the like.
D'autres avantages détaillés de l'invention apparaîtront au vu des exemples donnés dans le tableau comparatif ci-dessous à titre indicatif.Other detailed advantages of the invention will become apparent from the examples given in the comparative table below for information.
Le copolymère 1 est un copolymère selon l'état de la technique alors que les copolymères 2 à 6 sont mis en œuvre conformément à la présente invention.The copolymer 1 is a copolymer according to the state of the art while the copolymers 2 to 6 are used in accordance with the present invention.
Ces polyesters ont été utilisés pour la fabrication d'une bouteille de 50 cl selon le procédé ci-dessous : Les granulés de polyester sont fondus dans une monovis sans fin dont la température de fourreau est de 285°C. Le polyester fondu est alimenté dans un appareil d'injection de préformes commercialisé sous l'appellation « Presse HUSKY 48 empreintes XL 300 » avec une température d'injection comprise entre 262°C et 266°C et une pression de 450 bars. Le refroidissement des préformes est réalisé par circulation d'eau pour obtenir une température de 8,5°C. Le temps de cycle global pour l'injection est de 15,7 s. Après refroidissement des préformes, ces dernières sont alimentées dans une installation de soufflage pour la fabrication de bouteilles de contenance 0,5 1 présentant un col de forme référencée par l'appellation normalisée 28 PCO et un fond de forme pétaloïde à 5 pétales. Cette installation est commercialisée sous l'appellation « SIDEL SBO 1 F2 LAB ». Les préformes sont chauffées à une température de 87 °C. Le pré- soufflage est réalisé pendant 0,19 s sous une pression de soufflage de 8,5 bars tandis que le soufflage est conduit pendant 1,78 s sous une pression de soufflage de 38 bars. La vitesse de la canne d'étirage est de 1,2 m/s.These polyesters were used for the manufacture of a 50 cl bottle according to the process below: The polyester granules are melted in an endless monovis whose barrel temperature is 285 ° C. The molten polyester is fed into a preform injection device sold under the name "HUSKY 48 imprint XL 300 press" with an injection temperature between 262 ° C and 266 ° C and a pressure of 450 bars. The preforms are cooled by circulation of water to obtain a temperature of 8.5 ° C. The overall cycle time for injection is 15.7 s. After the preforms have cooled, the latter are fed into a blowing installation for the production of bottles with a capacity of 0.5 1 having a neck with a shape referenced by the standardized designation 28 PCO and a bottom with a petaloid shape with 5 petals. This installation is marketed under the name "SIDEL SBO 1 F2 LAB". The preforms are heated to a temperature of 87 ° C. Meadow- blowing is carried out for 0.19 s under a blowing pressure of 8.5 bars while blowing is carried out for 1.78 s under a blowing pressure of 38 bars. The speed of the drawing rod is 1.2 m / s.
Les caractéristiques des bouteilles obtenues et du procédé de soufflage sont indiquées dans le tableau ci-dessous pour chaque polyester PET utilisé.The characteristics of the bottles obtained and of the blowing process are indicated in the table below for each PET polyester used.
Tableau comparatif de différentes propriétés physico-chimiques Les viscosités des polyesters formant les parois des bouteilles sont de l'ordre de celles des polyesters utilisés.Comparative table of different physicochemical properties The viscosities of the polyesters forming the walls of the bottles are of the order of those of the polyesters used.
Bien entendu, l'invention n'est pas limitée au mode de réalisation décrit. Des modifications restent possibles, notamment du point de vue de la constitution des divers éléments ou par substitution d'équivalents techniques, sans sortir pour autant du domaine de protection de l'invention. Of course, the invention is not limited to the embodiment described. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without thereby departing from the scope of protection of the invention.

Claims

R E V E N D I C A T I O N S
1. Utilisation d'une résine PET présentant une viscosité intrinsèque (VI) inférieure à 0,65 dl/g pour la fabrication de préformes en résine PET puis de contenants réalisés dans ladite résine PET.1. Use of a PET resin having an intrinsic viscosity (VI) of less than 0.65 dl / g for the manufacture of preforms made of PET resin and then of containers produced in said PET resin.
2. Utilisation selon la revendication 1, caractérisée en ce que la viscosité intrinsèque (VI) est comprise entre 0,45 dl/g et 0,65 dl/g.2. Use according to claim 1, characterized in that the intrinsic viscosity (VI) is between 0.45 dl / g and 0.65 dl / g.
3. Utilisation selon la revendication 1 ou 2, caractérisée en ce que ladite préforme est composée d'une matière possédant une cristallinité inférieure à 10 %, de préférence inférieure à 5 %.3. Use according to claim 1 or 2, characterized in that said preform is composed of a material having a crystallinity of less than 10%, preferably less than 5%.
4. Préforme en résine PET obtenue par l'utilisation selon l'une quelconque des revendications 1 à 3, caractérisée en ce que la viscosité intrinsèque (VI) du polyester formant les parois de ladite préforme est comprise entre 0,45 dl/g et 0,65 dl/g.4. PET resin preform obtained by the use according to any one of claims 1 to 3, characterized in that the intrinsic viscosity (VI) of the polyester forming the walls of said preform is between 0.45 dl / g and 0.65 dl / g.
5. Contenant en résine PET, caractérisé en ce qu'il est composé d'une résine PET de viscosité intrinsèque inférieure à 0,65 dl/g. 5. Container in PET resin, characterized in that it is composed of a PET resin with an intrinsic viscosity of less than 0.65 dl / g.
6. Contenant selon la revendication 5, caractérisé en ce que la viscosité intrinsèque (VI) du PET formant les parois dudit contenant est comprise entre 0,45 dl/g et 0,65 dl/g.6. Container according to claim 5, characterized in that the intrinsic viscosity (VI) of the PET forming the walls of said container is between 0.45 dl / g and 0.65 dl / g.
7. Contenant selon la revendication 5 ou 6, caractérisé en ce que la densité du polyester formant les parois dudit contenant est comprise entre 1,36 et 1,37.7. Container according to claim 5 or 6, characterized in that the density of the polyester forming the walls of said container is between 1.36 and 1.37.
8. Contenant selon l'une quelconque des revendications 5 à 7, caractérisé en ce que la cristallinité moyenne du polyester formant les parois dudit contenant est comprise entre 25 % et 35 %.8. Container according to any one of claims 5 to 7, characterized in that the average crystallinity of the polyester forming the walls of said container is between 25% and 35%.
9. Contenant selon l'une quelconque des revendications 5 à 8, caractérisé en ce que sa perméabilité au dioxyde de carbone est améliorée d'au moins 5 % par rapport à celle d'un contenant obtenu avec une résine PET de viscosité intrinsèque (VI) supérieure ou égale à 0,65 dl/g.9. Container according to any one of claims 5 to 8, characterized in that its permeability to carbon dioxide is improved by at least 5% compared to that of a container obtained with a PET resin of intrinsic viscosity (VI ) greater than or equal to 0.65 dl / g.
10. Contenant alimentaire, en particulier bouteille alimentaire, de préférence bouteille alimentaire destinée à contenir de l'eau, selon l'une quelconque des revendications 5 à 9. 10. Food container, in particular a food bottle, preferably a food bottle intended to contain water, according to any one of claims 5 to 9.
EP02791514A 2001-07-31 2002-07-30 Methods for making polyethylene terephthalate (pet) preforms and containers such as food bottles, containers and intermediate preforms obtained Withdrawn EP1423246A1 (en)

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FR0110280 2001-07-31
FR0110280A FR2828129A1 (en) 2001-07-31 2001-07-31 Use of a polyethylene terephthalate resin with a low intrinsic viscosity to make preforms and containers, especially water bottles
PCT/FR2002/002748 WO2003011549A1 (en) 2001-07-31 2002-07-30 Methods for making polyethylene terephthalate (pet) preforms and containers such as food bottles, containers and intermediate preforms obtained

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US20040214981A1 (en) 2004-10-28
CN1556742A (en) 2004-12-22
FR2828129A1 (en) 2003-02-07
US7247698B2 (en) 2007-07-24
MXPA04000960A (en) 2005-02-17
TW587980B (en) 2004-05-21
AR034952A1 (en) 2004-03-24
WO2003011549A1 (en) 2003-02-13

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