EP1715989A1 - Verfahren und anlage zum entfeuchten, erwärmen und spritzgiessen von körnigen kunststoffmaterialien - Google Patents

Verfahren und anlage zum entfeuchten, erwärmen und spritzgiessen von körnigen kunststoffmaterialien

Info

Publication number
EP1715989A1
EP1715989A1 EP04804179A EP04804179A EP1715989A1 EP 1715989 A1 EP1715989 A1 EP 1715989A1 EP 04804179 A EP04804179 A EP 04804179A EP 04804179 A EP04804179 A EP 04804179A EP 1715989 A1 EP1715989 A1 EP 1715989A1
Authority
EP
European Patent Office
Prior art keywords
dehumidification
granules
temperature
moulding
injection
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Withdrawn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
EP04804179A
Other languages
English (en)
French (fr)
Inventor
Rinaldo Piva
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.)
Plastic Systems SpA
Original Assignee
Plastic Systems SpA
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 Plastic Systems SpA filed Critical Plastic Systems SpA
Publication of EP1715989A1 publication Critical patent/EP1715989A1/de
Withdrawn legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29BPREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B13/00Conditioning or physical treatment of the material to be shaped
    • B29B13/06Conditioning or physical treatment of the material to be shaped by drying
    • B29B13/065Conditioning or physical treatment of the material to be shaped by drying of powder or pellets
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29BPREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B13/00Conditioning or physical treatment of the material to be shaped
    • B29B13/02Conditioning or physical treatment of the material to be shaped by heating
    • B29B13/021Heat treatment of powders
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29BPREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B7/00Mixing; Kneading
    • B29B7/30Mixing; Kneading continuous, with mechanical mixing or kneading devices
    • B29B7/58Component parts, details or accessories; Auxiliary operations
    • B29B7/60Component parts, details or accessories; Auxiliary operations for feeding, e.g. end guides for the incoming material
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29BPREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B7/00Mixing; Kneading
    • B29B7/80Component parts, details or accessories; Auxiliary operations
    • B29B7/82Heating or cooling
    • B29B7/826Apparatus therefor
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29BPREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B9/00Making granules
    • B29B9/16Auxiliary treatment of granules
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C31/00Handling, e.g. feeding of the material to be shaped, storage of plastics material before moulding; Automation, i.e. automated handling lines in plastics processing plants, e.g. using manipulators or robots
    • B29C31/02Dispensing from vessels, e.g. hoppers
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17Component parts, details or accessories; Auxiliary operations
    • B29C45/18Feeding the material into the injection moulding apparatus, i.e. feeding the non-plastified material into the injection unit
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25Component parts, details or accessories; Auxiliary operations
    • B29C48/285Feeding the extrusion material to the extruder
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26DRYING
    • F26BDRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B17/00Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement
    • F26B17/12Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed solely by gravity, i.e. the material moving through a substantially vertical drying enclosure, e.g. shaft
    • F26B17/14Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed solely by gravity, i.e. the material moving through a substantially vertical drying enclosure, e.g. shaft the materials moving through a counter-current of gas
    • F26B17/1408Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed solely by gravity, i.e. the material moving through a substantially vertical drying enclosure, e.g. shaft the materials moving through a counter-current of gas the gas being supplied and optionally extracted through ducts extending into the moving stack of material
    • F26B17/1425Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed solely by gravity, i.e. the material moving through a substantially vertical drying enclosure, e.g. shaft the materials moving through a counter-current of gas the gas being supplied and optionally extracted through ducts extending into the moving stack of material the ducts being perforated and arranged vertically
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26DRYING
    • F26BDRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B21/00Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
    • F26B21/02Circulating air or gases in closed cycles, e.g. wholly within the drying enclosure
    • F26B21/04Circulating air or gases in closed cycles, e.g. wholly within the drying enclosure partly outside the drying enclosure
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26DRYING
    • F26BDRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B21/00Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
    • F26B21/06Controlling, e.g. regulating, parameters of gas supply
    • F26B21/08Humidity
    • F26B21/083Humidity by using sorbent or hygroscopic materials, e.g. chemical substances, molecular sieves
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26DRYING
    • F26BDRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B23/00Heating arrangements
    • F26B23/001Heating arrangements using waste heat
    • F26B23/002Heating arrangements using waste heat recovered from dryer exhaust gases
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26DRYING
    • F26BDRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B3/00Drying solid materials or objects by processes involving the application of heat
    • F26B3/02Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air
    • F26B3/06Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air the gas or vapour flowing through the materials or objects to be dried
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C2045/0096Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor drying the moulding material before injection, e.g. by heating
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C35/00Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
    • B29C35/02Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/022Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the choice of material
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25Component parts, details or accessories; Auxiliary operations
    • B29C48/285Feeding the extrusion material to the extruder
    • B29C48/286Raw material dosing
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25Component parts, details or accessories; Auxiliary operations
    • B29C48/285Feeding the extrusion material to the extruder
    • B29C48/295Feeding the extrusion material to the extruder in gaseous form
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25Component parts, details or accessories; Auxiliary operations
    • B29C48/78Thermal treatment of the extrusion moulding material or of preformed parts or layers, e.g. by heating or cooling
    • B29C48/80Thermal treatment of the extrusion moulding material or of preformed parts or layers, e.g. by heating or cooling at the plasticising zone, e.g. by heating cylinders
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING 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
    • B29K2067/00Use of polyesters or derivatives thereof, as moulding material
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING 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
    • B29K2067/00Use of polyesters or derivatives thereof, as moulding material
    • B29K2067/006PBT, i.e. polybutylene terephthalate
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26DRYING
    • F26BDRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B2200/00Drying processes and machines for solid materials characterised by the specific requirements of the drying good
    • F26B2200/08Granular materials

Definitions

  • the present invention relates to a process of dehumidification and of injection and moulding for granulated plastics materials according to the characteristics set forth in the preamble to independent Claim 1.
  • the invention is also directed towards a plant arranged to operate in accordance with the process, according to the preamble to independent Claim 10.
  • Technological background In the field of methods for the processing of granulated plastics materials by injection and moulding, it is known that the granules have to reach the injection and moulding press with a moisture level which is as low as possible (or in any case is controlled in dependence on the type of final product to be produced). For this purpose, the granules are normally subjected to a dehumidification step immediately upstream of the injection and moulding step.
  • the step of dehumidification of the granules is carried out in a hopper by stripping of the moisture contained in the granules with air which is caused to flow as a counter-current.
  • the air admitted to the hopper has an extremely low moisture content and a relatively high temperature.
  • the need is known to maintain the temperature as high as possible, not only in view of possible improvements in terms of the drying of the granules but also in view of a reduction in the cycle times of the injection and moulding press which is typically disposed immediately downstream of the dehumidification step.
  • this apparatus in fact, before the granules are injected into the mould, they have to be brought to the melting point of the polymer in a suitable heating chamber, requiring a certain amount of time which forms part of the overall cycle time of the press.
  • the increase in temperature within the dehumidification step is limited, however, by the fact that high temperature promotes undesired oxidative degradation reactions of the polymer, compromising the final quality of the product.
  • a range of temperature values which is normally used as an optimal compromise between the requirements set out above is between 180°C and 190°C.
  • the PET granules are supplied to the injection and moulding apparatus which brings them to a temperature of about 280°C - 290°C, ready to be injected into the mould.
  • the problem underlying the present invention is that of providing a process of dehumidification and of injection and moulding for granulated plastics materials, as well as a plant arranged to operate in accordance with the process, which are designed structurally and functionally to respond to the requirements set out above, overcoming the limitations of the prior art mentioned.
  • This problem is solved by the present invention by means of a process of dehumidification and of injection and moulding, as well as a plant operating in accordance with the process, according to the appended claims.
  • the plant 1 is intended for the dehumidification of polyethylene terephthalate (PET) granules and comprises, as a whole, a dehumidification unit la for dehumidifying the granules, and an injection and moulding unit lb disposed downstream of the dehumidification unit la.
  • the dehumidification unit la in turn comprises a hopper 2, a granule-loading system 3 for loading the granules into the hopper 2, as well as a circuit 4 for the admission and treatment of the process air for removing moisture from the granules inside the hopper 2.
  • the hopper 2 is loaded with granules from above by means of the loading system 3 which comprises a suction line 5 for the pneumatic transportation of the granules.
  • the suction line 5 opens at a first end in a granule storage tank 6 and is connected to a cyclone 7, which is disposed at the top of the hopper 2 and in which the granules are separated from the transportation air and are allowed to fall into the hopper, and then to a vacuum pump 8.
  • the granules come into contact with process air which is admitted from the bottom 2a of the hopper 2 as a counter- current relative to the granules, at a dehumidification temperature.
  • the process-air admission and treatment circuit 4 comprises a dehumidifier 10, for example, of the type with molecular sieves, which is connected downstream to a heater 11 and then to a line 12 for admitting the air to the hopper 2.
  • the circuit 4 is completed by a line 13 for recovering the process air from the hopper; the line 13 connects the top of the hopper 2 to a pair of filters 14 and then to a heat recovery unit 15 and finally to the dehumidifier 10.
  • the operation of the dehumidifier 10 is controlled by a control unit 16.
  • the above-mentioned components are dimensioned and controlled in accordance with procedures known in the technical field in question and will not therefore be described in greater detail.
  • the bottom 2a of the hopper 2 is connected downstream to the injection and moulding unit lb which comprises, for example, an injection and moulding press arranged for the manufacture of PET-based articles or semi-finished products.
  • the injection and moulding press in turn comprises a heating chamber for bringing the granules to a moulding temperature which, in the case of PET, is between 280°C and 290°C, and a mould into which the molten plastics material is admitted.
  • granule- heating means are interposed between the dehumidification unit la and the injection and moulding unit lb.
  • the granule-heating means 20 comprise a hopper 21 and a circuit
  • the hopper 21 is connected at its top to the bottom of the hopper 2 by means of a duct 23 and at its bottom to the injection and moulding unit lb by means of a duct 24 and is preferably provided with stirring means 21b for keeping the granules inside it in motion.
  • the circuit 22 comprises gas-movement means, for example, a blower 25 which is connected by means of a line 26 to a heater 27, preferably of an electric type, and to the bottom 21a of the hopper 21, where the gas is put in contact with the granules, flowing as a counter- current relative thereto, towards the top of the hopper 21. From there, the gas is led back to the blower 25 by means of the return line 28, after passing through a filter 29.
  • the gas used in the circuit 22 is a substantially oxygen-free gas, that term being intended to indicate generally a presence of less than about 5% of oxygen.
  • the gas is preferably technical nitrogen and can be introduced into the circuit 22, for example for operations for the replenishment thereof, by means of a coupling 30 provided in the line 26.
  • the granule-heating means 20 further comprise a control unit 35 which is arranged for the control and overall management of that step of the process, as described in greater detail in the following paragraphs.
  • the process according to the present invention comprises a first step for the dehumidification of the granules with process air.
  • the granules are loaded into the hopper 2 at the top thereof by means of the loading system 3 and the process air is admitted from the bottom 2a as a counter-current, at a temperature such that the granules inside the hopper are at a dehumidification temperature of between 180°C and 190°C.
  • the process air output from the hopper 2 preheats the process air output from the dehumidifier 10 in the heat recovery unit 15 and is sent to the dehumidifier 10 in order to be treated in the molecular sieves thereof.
  • the process air has a very low moisture level with a dew point typically of between -50°C and -60 O C.
  • the process air is admitted to the hopper 2, it is then preheated in the heat recovery unit 15 and is brought to the final temperature by the heater 11.
  • the granules are then supplied, by falling through the duct 23, into the hopper 21 where they are heated by contact with the gas admitted through the circuit 22 to a supply temperature between the dehumidification temperature and the moulding temperature.
  • the granules are preferably brought to a supply temperature of between 200°C and 250°C, even more preferably between 220°C and 230°C. It should be noted that the granules are heated to a supply temperature lower than the softening point of the granules which, for PET, is of the order of 270°C, so as not to create problems when they pass from the hopper 21 to the injection and moulding press due to sticking of the granules. In any case, the mixing to which the granules are subjected by virtue of the action of the stirring means 21b is such as to prevent the establishment of local hot spots which could lead to the above-mentioned sticking problems.
  • the granule-heating means 20 are of dimensions such that the granules remain in the hopper 21 for sufficient time to reach the supply temperature indicated above. Granules are thus supplied to the injection and moulding unit at a higher temperature and the unit thus requires less time to bring them to the moulding temperature.
  • the heating step thus promotes the process of the plasticization of the granules within the injection and moulding press, also leading to less thermal degradation of the PET and a lower energy consumption for the operation of the press.
  • the gas is preferably technical nitrogen. It is found that undesired degradation reactions of the PET are thus not triggered, in spite of the high temperature reached. Although the use of technical nitrogen remains the greatly preferred option, the gas may be constituted by air with a low oxygen content.
  • the gas may even result from the use, in closed circuit for a suitable period of time, of process air drawn from the circuit 4 (variant shown in Figure 1 by means of the discontinuous connecting line 31). If the process air is recirculated continuously in the hopper 21, the fraction of oxygen therein will in fact reduce over time because of oxidative reactions with the plastics material present therein until it reaches the percentages indicated above which enable further possible degradation reactions to be prevented. Naturally, during this recirculation stage in which the oxygen fraction is still high, a lower temperature of the gas will have to be maintained unless a generally lower quality of the granules output from the hopper 21 is acceptable.
  • the present invention thus solves the problem discussed above with reference to the prior art mentioned, at the same time offering many further advantages, amongst which is an increase in the productivity of the dehumidification and injection and moulding plants without compromising the quality of the final product.
  • Another advantage is that operation in an environment that is substantially free of oxygen also minimizes degradative reactions which might lead to the undesired formation of aldehydes, particularly formaldehyde and acetaldehyde which, with their strong and pungent odours, can adversely affect the flavour of any beverage contained in bottles produced from the granules of plastics material.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Chemical & Material Sciences (AREA)
  • Sustainable Development (AREA)
  • General Chemical & Material Sciences (AREA)
  • Microbiology (AREA)
  • Robotics (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
  • Injection Moulding Of Plastics Or The Like (AREA)
EP04804179A 2004-02-16 2004-12-22 Verfahren und anlage zum entfeuchten, erwärmen und spritzgiessen von körnigen kunststoffmaterialien Withdrawn EP1715989A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT000037A ITPD20040037A1 (it) 2004-02-16 2004-02-16 Processo di deumidificazione e di iniezione e stampaggio di materie plastiche in granuli ed impianto predisposto per operare secondo tale processo
PCT/EP2004/014583 WO2005077628A1 (en) 2004-02-16 2004-12-22 Process and plant for dehumidification, heating and injection moulding of granulated plastics materials

Publications (1)

Publication Number Publication Date
EP1715989A1 true EP1715989A1 (de) 2006-11-02

Family

ID=34856949

Family Applications (1)

Application Number Title Priority Date Filing Date
EP04804179A Withdrawn EP1715989A1 (de) 2004-02-16 2004-12-22 Verfahren und anlage zum entfeuchten, erwärmen und spritzgiessen von körnigen kunststoffmaterialien

Country Status (4)

Country Link
EP (1) EP1715989A1 (de)
CA (1) CA2555611A1 (de)
IT (1) ITPD20040037A1 (de)
WO (1) WO2005077628A1 (de)

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IT1393078B1 (it) * 2009-01-26 2012-04-11 Plastodidattica Commerciale S R L Metodo per la produzione di lenti di presentazione.
JP2012180999A (ja) * 2011-03-03 2012-09-20 Kawata Mfg Co Ltd 乾燥システムおよび乾燥方法
JP6076820B2 (ja) * 2013-04-24 2017-02-08 株式会社カワタ 粉粒体の計量混合装置
IT201800011013A1 (it) * 2018-12-12 2020-06-12 Pegaso Ind S P A Processo di lavorazione di materiale granulare polimerico ed impianto operante secondo tale processo
CN110631328A (zh) * 2019-10-15 2019-12-31 昆山森驰机械设备有限公司 一种除湿干燥机
CN110893661B (zh) * 2019-12-27 2020-07-17 江苏惠利隆塑业集团有限公司 一种注塑成型原料的处理装置
IT202000007147A1 (it) * 2020-04-03 2021-10-03 Piovan Spa Apparato e Metodo di Trattamento di Materiale Incoerente
CN218504963U (zh) * 2022-07-05 2023-02-21 摩丹智能制造(太仓)有限公司 一种具有塑料颗粒混合和干燥功能的一体式智能干燥装置

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1226101A (fr) * 1958-12-20 1960-07-08 Inventa Ag Procédé et appareillage pour sécher des polyamides en granules
JPS5949881B2 (ja) * 1978-01-31 1984-12-05 ユニチカ株式会社 合成樹脂チツプの連続向流乾燥方法
JPS62201204A (ja) * 1986-03-01 1987-09-04 Konishiroku Photo Ind Co Ltd 熱可塑性樹脂製シ−トの製造方法および装置
DE4314345A1 (de) * 1993-04-30 1994-11-17 Reinhard Dr Unger Verfahren und Vorrichtung zur Wiederaufbereitung von festem Polyestermaterial
DE19957664A1 (de) * 1999-11-30 2001-05-31 Basf Ag Vorrichtung zum Trocknen und thermischen Behandeln von Granulat mit einem Inertgasstrom

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2005077628A1 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022111514A1 (zh) * 2020-11-27 2022-06-02 湖南连心科技有限公司 一种环保型粉末涂料挤出设备

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