EP0925167A1 - Procede de plastification, tamisage, dosage et transport de produits de fusion a forte viscosite et dispositif de mise en oeuvre de ce procede - Google Patents

Procede de plastification, tamisage, dosage et transport de produits de fusion a forte viscosite et dispositif de mise en oeuvre de ce procede

Info

Publication number
EP0925167A1
EP0925167A1 EP97944813A EP97944813A EP0925167A1 EP 0925167 A1 EP0925167 A1 EP 0925167A1 EP 97944813 A EP97944813 A EP 97944813A EP 97944813 A EP97944813 A EP 97944813A EP 0925167 A1 EP0925167 A1 EP 0925167A1
Authority
EP
European Patent Office
Prior art keywords
gear pump
extruder
melt
vacuum lock
disposed
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Withdrawn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
EP97944813A
Other languages
German (de)
English (en)
Inventor
Andreas Limper
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.)
Individual
Original Assignee
Individual
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
Priority claimed from DE19635706A external-priority patent/DE19635706C2/de
Application filed by Individual filed Critical Individual
Publication of EP0925167A1 publication Critical patent/EP0925167A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
    • B29C48/50—Details of extruders
    • B29C48/76—Venting, drying means; Degassing means
    • B29C48/765—Venting, drying means; Degassing means in the extruder apparatus
    • B29C48/766—Venting, drying means; Degassing means in the extruder apparatus in screw extruders
    • B29C48/767—Venting, drying means; Degassing means in the extruder apparatus in screw extruders through a degassing opening of a barrel
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/285—Feeding the extrusion material to the extruder
    • B29C48/288—Feeding the extrusion material to the extruder in solid form, e.g. powder or granules
    • B29C48/2888—Feeding the extrusion material to the extruder in solid form, e.g. powder or granules in band or in strip form, e.g. rubber strips
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
    • B29C48/365—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using pumps, e.g. piston pumps
    • B29C48/37—Gear pumps
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
    • B29C48/375—Plasticisers, homogenisers or feeders comprising two or more stages
    • B29C48/387—Plasticisers, homogenisers or feeders comprising two or more stages using a screw extruder and a gear pump
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
    • B29C48/395—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion 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

Definitions

  • the invention concerns a process for plastification, straining, dosing and transporting high viscous melts, for example a thermoplastic resin or a rubber compound, using a gear pump and a screw machine as well as a device for carrying out the process .
  • gear pumps for the processing of high viscous melts is well known. Good performance of the pump can be achieved with special construction details as e. g. described in DE 413031261, EP 050828511, EP 0559582 Al, EP 0595764 Al .
  • the use of a combination of gear pump and extruder is also well known (see e. g. EP 0513 593 A2 , EP 0508 079 A2 , EP 0508 080 A2) .
  • rubber compounds can be pre-warmed at a separate device, normally an open roll mill.
  • the material preheated in this manner - which' then has a low yield stress - is fed to a so-called warm fed extruder.
  • the throughput of the above mentioned cold fed extruder exhibits large variations due to the geometry of the feed strip. Therefore a separate strip processing step is necessary or variations in the geometry of the extrudate have to be accepted.
  • the underlying purpose of the invention is to develop a method to plasticize, strain, dose and transport high viscous melts and to develop a unit which avoids the described disadvantages of prior art. This purpose is achieved by a process in which:
  • the melt (or the cold rubber compound) is fed to a gear pump in an unplasticized form or is pulled into the gear pump via its gear wheels
  • the melt, which has been plasticized by the gear pump is directly fed to a screw machine.
  • a vacuum pump can be used to .evacuate the feed zone of a "conventional" screw, i. e. this zone operates at a low pressure.
  • the screw can be constructed in such a manner that it has a vacuum lock.
  • the feed zone to which the gear pump delivers the plasticized melt produces the pressure to overcome the resistance of the vacuum lock. While passing the ribbed surface of the lock, the stream of plasticized material is flattened out and air inclusions are transported to the surface. In the vacuum zone following the vacuum lock, fluent components can be suctioned off.
  • the gear pump itself is used to produce the pressure to overcome the vacuum lock (as shown in Figs. 3 to 5) .
  • the feed zone of the extruder could be completely eliminated.
  • Distribution of the compound over the circumference of the screw is effected either by a mandrel die or by a special groove in the barrel surface.
  • the material is plasticized homogeneously without over-heated spots
  • constant pressure build-up can be achieved in the unit so that variations in the cross section of the feed strip only result in minor changes in the extrudate geometry.
  • the device in accordance with the invention can achieve high throughputs without the disadvantages of usual "cold fed” machines.
  • the feed strips normally used in the rubber industry could be directly drawn-in by the gear pump from beds, boxes or the like. This forced feed action causes surface effects, which are dominant in conventional extruder feed zones, to not play a significant role.
  • a new concept in accordance with the invention is the fact that, for the first time, the properties of the gear pump as a premastication unit are used and integrated into the overall concept.
  • the system effects further solutions to the problem of air inclusions via the gear pump.
  • the gear pump is not used as a dosing unit at the tip of the screw, rather delivers a preplasticized melt to the downstream screw machine.
  • the screw of same can be deeply cut. A large channel depth is possible without the danger of build-up of a "cold core" .
  • a principal aspect of the invention is the fact that the gear pump directly feeds an extruder.
  • Figure 1 shows a cross section through a unit comprising a gear pump and a screw extruder
  • Figure 2 shows another unit in a schema-tic fashion
  • Figure 5 show solutions for melts which have to fulfill high requirements with respect to devolatilization .
  • the device shown in figure 1 illustrates a gear pump 1 and an extruder 2, characterized by the fact that the extruder 2 is fed by gear pump 1.
  • the rubber 3 is initially fed in region 3S, to the gear pump or it is drawn-in by the pump 1 itself.
  • the material is plasticized as it passes through the pump by gear wheels IZ of pump 1.
  • the melt 3 leaving the pump 1 is fed directly to the extruder 2.
  • a pressure measuring device 4 is disposed at outlet 1A of the gear pump 1 to measure the pressure directly at outlet 1A during processing. The measured values are introduced to a regulation device 5 to regulate the rate of revolution of gear pump 1.
  • a pressure measuring device 4 is disposed in the first cylinder zone 7 following the feed zone to measure the pressure in the cylinder zone 7 during processing and to introduce the measured values to the regulation device 5. Since the rate of revolution of gear pump 1 is changed by regulation device 5 in dependence on a pressure signal of the extruder 2, the regulation device 5 guarantees a constant throughput of the downstream extruder 2 and smooths out feed fluctuations of short time constant, possibly caused by irregularities in the rubber strips 3S. In this manner the user has access to an additional parameter for controlling processing.
  • a suction device 8 is disposed at the draw-in zone 2E of the extruder 2.
  • the draw-in zone 2E can be configured in such a manner that it accommodates high mass pressures. This is possible since the draw-in zone 2E does not have an opening which is as large as that of the draw-in zones of conventional rubber extruders. Since, in the present case, the extruder 2 is fed via the gear pump 1, the cylinder surrounding the screw can be closed such that the feed zone is the only opening in the wall of the cylinder. Since the gear pump 1 can also transport in opposition to high pressures, substantial pressure levels can already be achieved in the draw-in zone 2E of the device in accordance with the invention.
  • At least one roller 10 is loaded by a weight 9 for monitoring the pressure with which the rubber strip 3S is introduced to the gear pump 1 or with which same is drawn-in thereby.
  • An apertured plate 11, a sieve package or the like is provided for at the outlet 1A of the gear pump 1 for filtering the rubber 3.
  • the rubber 3 is subjected to a large shear force in the gear pump 1 for only a short period of time whereas, in contrast to conventional extruders, the absolute path depths in the gear pump 1 are relatively small so that a homogeneous shearing is effected over the entire cross section of the rubber 3.
  • the gear pump 1 is capable of building-up relatively high pressures. Since the temperature increase in the gear pump 1 assumes values of approximately 60 to 80°C, the rubber 3 is thereby filtered at a temperature of about 80 to 100°C, departing from a room temperature of 25°C.
  • the device in accordance with the invention therefore describes a manner in which the rubber 3 can be filtered at a substantially cooler level.
  • the rubber 3 is, however, also preheated in a homogeneous fashion via the extrusion of the rubber 3 through the apertured plates 11 or through a sieve package.
  • additional gear pumps 1.1, 1.2, ...l.n are provided for downstream of gear pump 1.
  • Extruder 2 is located downstream of the last gear pump l.n. This configuration of the device in accordance with the invention facilitates a larger temperature increase than that achievable with a single gear pump 1.
  • each gear pump 1.1, 1.2 ... l.n acts as an attenuator for feed fluctuations so that a flow of rubber 3 having higher regularity can be achieved at the outlet of the last gear pump l.n.
  • the extruder can be eliminated and a die can be fed directly by the gear pump.
  • FIGs 3, 4, and 5 show an extruder 2 having a vacuum lock 12.
  • the feed zone is constructed in such a way as to facilitate a significant pressure build-up (as also described in figure 1) .
  • the vacuum pump suctions the material at a barrel position behind the vacuum lock 12.
  • Pressure measuring devices 4 measure pressure in the outlet location P(1A), the transfer location P(6), and the cylinder zone P(7) and transfer the corresponding signals P1A, P6, and P7 to regulation device 5 for regulation of the rate of revolution n of the gear pump 1. Since the gear pump produces a substantial pressure (and the feed zone as well) , the screw can be of shorter construction than conventional devolatilization extruders.
  • Figure 4 shows a device, wherein the extruder 2 has no characteristic feed zone whatsoever.
  • the preplasticized material is transported by the gear pump 1 and pressed directly onto a cylindrical coating mandrel 13 disposed in a stationary manner surrounding rotating vacuum lock 12 to enlarge the surface of the extrudate and distribute it over the circumference of " the screw surface of the vacuum lock 12.
  • Figure 5 shows a device wherein the extruder is provided with a spiral groove 15 in the barrel wall which distributes the material in a manner described in relation to Fig. 4.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)

Abstract

L'invention concerne un procédé pour plastifier, filtrer, doser et transporter des produits polymères (3) en fusion à forte viscosité, par exemple des composés de caoutchouc ou des résines thermoplastiques, via une pompe à engrenages (1) et une extrudeuse (2). Selon ce procédé, le produit en fusion (3) est introduit dans la pompe à engrenages (1) et étiré dans cette dernière, dans un état non plastifié. La plastification du produit en fusion (3) est réalisée pendant le transport à l'aide des dents (1Z) de la pompe à engrenages (1) et le produit (3) est ensuite directement transféré dans l'extrudeuse (2) à l'état plastifié. Dans un dispositif prévu pour mettre en oeuvre ce procédé, l'extrudeuse (2) est placée en aval de la pompe à engrenages (1).
EP97944813A 1996-09-03 1997-08-30 Procede de plastification, tamisage, dosage et transport de produits de fusion a forte viscosite et dispositif de mise en oeuvre de ce procede Withdrawn EP0925167A1 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
DE19635706 1996-09-03
DE19635706A DE19635706C2 (de) 1996-09-03 1996-09-03 Verfahren zum Plastifizieren, Sieben, Dosieren und Fördern hochviskoser Kautschukmischungen und Einrichtung für die Durchführung des Verfahrens
US5609097P 1997-08-28 1997-08-28
US56090P 1997-08-28
PCT/EP1997/004727 WO1998009792A1 (fr) 1996-09-03 1997-08-30 Procede de plastification, tamisage, dosage et transport de produits de fusion a forte viscosite et dispositif de mise en oeuvre de ce procede

Publications (1)

Publication Number Publication Date
EP0925167A1 true EP0925167A1 (fr) 1999-06-30

Family

ID=26028988

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97944813A Withdrawn EP0925167A1 (fr) 1996-09-03 1997-08-30 Procede de plastification, tamisage, dosage et transport de produits de fusion a forte viscosite et dispositif de mise en oeuvre de ce procede

Country Status (2)

Country Link
EP (1) EP0925167A1 (fr)
WO (1) WO1998009792A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1159120A1 (fr) * 1999-03-11 2001-12-05 A-Z Formen- und Maschinenbau GmbH Extrudeuses monorotor
GB0009307D0 (en) * 2000-04-15 2000-05-31 Az Formen & Masch Gmbh Cold feed gear pump extruders
FR3067963A1 (fr) * 2017-06-22 2018-12-28 Compagnie Generale Des Etablissements Michelin Installation et procede de coextrusion
JP7338171B2 (ja) * 2019-03-01 2023-09-05 住友ゴム工業株式会社 ゴム押出機及びゴム押出方法

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1466689A (fr) * 1966-01-21 1967-01-20 Barmag Barmer Maschf Extrudeuse perfectionnée, alimentée en matière thermoplastique déjà plastifiée et son procédé d'utilisation
DE3233416C3 (de) * 1982-09-09 1996-08-29 Klaus Kalwar Schneckenpresse zur Verarbeitung von Kunststoffen
US4537568A (en) * 1982-09-15 1985-08-27 Jochnick & Norrman Press Ab Force pump
DE4024994C2 (de) * 1990-08-07 1995-08-24 Krauss Maffei Ag Vorrichtung zum Beschicken von Spritzgieß- und Extrudereinheiten

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9809792A1 *

Also Published As

Publication number Publication date
WO1998009792A1 (fr) 1998-03-12

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