CH680659A5 - - Google Patents
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- Publication number
- CH680659A5 CH680659A5 CH2259/89A CH225989A CH680659A5 CH 680659 A5 CH680659 A5 CH 680659A5 CH 2259/89 A CH2259/89 A CH 2259/89A CH 225989 A CH225989 A CH 225989A CH 680659 A5 CH680659 A5 CH 680659A5
- Authority
- CH
- Switzerland
- Prior art keywords
- pipe
- section
- die
- straight portion
- narrowed section
- Prior art date
Links
- 239000012815 thermoplastic material Substances 0.000 claims description 23
- 238000007493 shaping process Methods 0.000 claims description 10
- 210000003462 vein Anatomy 0.000 claims description 10
- 238000000034 method Methods 0.000 claims description 8
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 238000011144 upstream manufacturing Methods 0.000 claims description 4
- 239000000463 material Substances 0.000 claims description 3
- -1 polyethylene Polymers 0.000 description 4
- 239000000203 mixture Substances 0.000 description 3
- 239000004800 polyvinyl chloride Substances 0.000 description 3
- 229920000915 polyvinyl chloride Polymers 0.000 description 3
- 239000011347 resin Substances 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- 229920001169 thermoplastic Polymers 0.000 description 3
- 239000004416 thermosoftening plastic Substances 0.000 description 3
- 239000004925 Acrylic resin Substances 0.000 description 2
- 229920000178 Acrylic resin Polymers 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229920001890 Novodur Polymers 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- 239000004743 Polypropylene Substances 0.000 description 2
- 239000004793 Polystyrene Substances 0.000 description 2
- 241000219793 Trifolium Species 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 229920000098 polyolefin Polymers 0.000 description 2
- 229920001155 polypropylene Polymers 0.000 description 2
- 229920002223 polystyrene Polymers 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 2
- 229920002554 vinyl polymer Polymers 0.000 description 2
- 239000004604 Blowing Agent Substances 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 239000004605 External Lubricant Substances 0.000 description 1
- 239000004610 Internal Lubricant Substances 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000013043 chemical agent Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000010816 packaging waste Substances 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
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
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/34—Auxiliary operations
- B29C44/36—Feeding the material to be shaped
- B29C44/46—Feeding the material to be shaped into an open space or onto moving surfaces, i.e. to make articles of indefinite length
- B29C44/50—Feeding the material to be shaped into an open space or onto moving surfaces, i.e. to make articles of indefinite length using pressure difference, e.g. by extrusion or by spraying
- B29C44/507—Feeding the material to be shaped into an open space or onto moving surfaces, i.e. to make articles of indefinite length using pressure difference, e.g. by extrusion or by spraying extruding the compound through an annular die
-
- 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
- B29C48/09—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
-
- 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
- B29C48/16—Articles comprising two or more components, e.g. co-extruded layers
- B29C48/18—Articles comprising two or more components, e.g. co-extruded layers the components being layers
- B29C48/21—Articles comprising two or more components, e.g. co-extruded layers the components being layers the layers being joined at their surfaces
-
- 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
- B29C48/30—Extrusion nozzles or dies
- B29C48/32—Extrusion nozzles or dies with annular openings, e.g. for forming tubular articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- 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
- B29C48/30—Extrusion nozzles or dies
- B29C48/32—Extrusion nozzles or dies with annular openings, e.g. for forming tubular articles
- B29C48/335—Multiple annular extrusion nozzles in coaxial arrangement, e.g. for making multi-layered tubular articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- 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
- B29C48/09—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
- B29C48/10—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels flexible, e.g. blown foils
-
- 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
- B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
- B29K2995/0037—Other properties
- B29K2995/0072—Roughness, e.g. anti-slip
-
- 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
- B29L2023/00—Tubular articles
- B29L2023/22—Tubes or pipes, i.e. rigid
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Extrusion Moulding Of Plastics Or The Like (AREA)
- Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
Description
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CH 680 659 A5 CH 680 659 A5
Description Description
La présente invention concerne un procédé pour réaliser, par coextrusion, un tuyau allégé comportant une âme en matière thermoplastique expansée et des parois interne et externe en matière thermoplastique dense ainsi qu'une filière convenant particulièrement pour sa réalisation. The present invention relates to a method for producing, by coextrusion, a lightened pipe comprising a core of expanded thermoplastic material and internal and external walls of dense thermoplastic material as well as a die particularly suitable for its production.
Dans le brevet européen EP-Bi 0 019 564, on divulgue déjà un procédé pour réaliser par coextrusion un tel tuyau dans lequel on coextrude les matières thermoplastiques fondues constitutives du tuyau au travers d'une tête de répartition de façon à former trois veines tubulaires des matières thermoplastiques en contact constituant l'ébauche du tuyau désiré et dans lequel on fait ensuite passer les trois veines en contact au travers d'une filière classique pour tuyau comportant un divergent-convergent et une portion droite de conformation du tuyau. In European patent EP-Bi 0 019 564, there is already disclosed a process for producing by coextrusion such a pipe in which the melted thermoplastic materials constituting the pipe are coextruded through a distribution head so as to form three tubular veins of the thermoplastic materials in contact constituting the blank of the desired pipe and in which the three veins in contact are then passed through a conventional pipe die comprising a diverging-converging and a straight portion of conformation of the pipe.
Dans un tel procédé, les veines de matière thermoplastique s'écoulant dans le divergent-convergent passent au travers d'un trèfle dont les branches ou ailettes porte-noyau provoquent des séparations longitudinales dans les veines d'écoulement, la partie convergente assurant un resoudage de l'ébauche. Il apparaît toutefois que le tuyau allégé finalement produit présente généralement des marques longitudinales résultant de cette séparation, qui nuisent à son aspect et qui constituent des zones de résistance mécanique amoindrie. In such a process, the veins of thermoplastic material flowing in the diverging-converging pass through a clover whose branches or core-carrying fins cause longitudinal separations in the flow-through veins, the converging part ensuring a soldering of the draft. However, it appears that the lightened pipe finally produced generally has longitudinal marks resulting from this separation, which detract from its appearance and which constitute zones of reduced mechanical resistance.
On peut certes améliorer l'aspect du tuyau allégé ainsi produit en réalisant la zone convergente de la filière de façon telle que ses parois soient elles-mêmes convergentes ainsi qu'il est montré sur la figure illustrative du dessin annexé au brevet européen susmentionné. It is certainly possible to improve the appearance of the lightened pipe thus produced by making the converging zone of the die so that its walls are themselves converging as shown in the illustrative figure of the drawing annexed to the above-mentioned European patent.
On constate toutefois que ce moyen est d'une efficacité aléatoire, en particulier lorsque le tuyau allégé produit est de diamètre élevé, supérieur à 25 cm ou d'épaisseur de paroi supérieure à 5 mm. However, it is found that this means is of random effectiveness, in particular when the lightened pipe produced is of large diameter, greater than 25 cm or of wall thickness greater than 5 mm.
La présente invention a pour premier objectif de fournir un procédé amélioré qui permet la production de tuyaux allégés qui sont dépourvus de toute trace provoquée par les ailettes porte-noyau et qui présentent de ce fait une résistance mécanique améliorée. The primary object of the present invention is to provide an improved process which allows the production of lightweight pipes which are free from any trace caused by the core-carrying fins and which therefore have improved mechanical strength.
La présente invention concerne dès lors un procédé pour réaliser, par coextrusion, un tuyau allégé comportant une âme en matière thermoplastique expansée et des parois interne et externe en matière thermoplastique dense dans lequel on coextrude les matières thermopiastiques fondues constitutives du tuyau au travers d'une tête de répartition de façon à former trois veines tubulaires des matières thermoplastiques en contact constituant l'ébauche du tuyau désiré et dans lequel on fait ensuite passer les trois veines en contact au travers d'une filière pour tuyau comportant un divergent-convergent et une portion droite de conformation du tuyau qui se caractérise en ce que, dans la portion droite de conformation, on fait passer les trois veines de matière thermoplastique dans une zone de section rétrécie, en amont de l'orifice de sortie, de façon à engendrer un accroissement de pression de 2.106 à 15.106 Pascals dans les matières thermoplastiques s'écoulant dans le convergent de la filière. The present invention therefore relates to a process for producing, by coextrusion, a lightened pipe comprising a core of expanded thermoplastic material and internal and external walls of dense thermoplastic material in which the molten thermopiastic materials constituting the pipe are coextruded through a distribution head so as to form three tubular veins of the thermoplastic materials in contact constituting the blank of the desired pipe and in which the three veins in contact are then passed through a pipe die comprising a diverging-convergent and a portion straight line of the pipe, which is characterized in that, in the straight portion of the line, the three veins of thermoplastic material are passed through a zone of narrowed section, upstream of the outlet orifice, so as to generate an increase pressure from 2.106 to 15.106 Pascals in thermoplastics flowing in s the converging sector.
La matière thermoplastique constitutive des parois interne et externe peut être quelconque et être notamment une résine vinylique telle que le polychlorure de vinyle, une polyoléfine telle que du polyéthylène ou du polypropylène, une résine styrénique telle que le polystyrène ou encore une résine acrylique telle un copolymère du type ABS. Les parois interne et externe peuvent être, au choix, réalisées à partir de matières thermoplastiques identiques ou différentes. La matière thermoplastique constitutive de l'âme peut être une résine vinylique telle le polychlorure de vinyle, une résine styrénique telle le polystyrène, une polyoléfine telle le polyéthylène et le polypropylène, ou encore une résine acrylique telle qu'un copolymère du type ABS, ces résines contenant un agent d'expansion constitué par un liquide volatile tel un hydrocarbure ou par un agent chimique tel qu'un agent libérant de l'azote comme décrit dans le brevet britannique GB-A 1 211 860. The thermoplastic material constituting the internal and external walls may be any and in particular be a vinyl resin such as polyvinyl chloride, a polyolefin such as polyethylene or polypropylene, a styrenic resin such as polystyrene or an acrylic resin such as a copolymer ABS type. The internal and external walls can be, as desired, made from identical or different thermoplastic materials. The thermoplastic material constituting the core may be a vinyl resin such as polyvinyl chloride, a styrenic resin such as polystyrene, a polyolefin such as polyethylene and polypropylene, or an acrylic resin such as a copolymer of the ABS type, these resins containing a blowing agent constituted by a volatile liquid such as a hydrocarbon or by a chemical agent such as a nitrogen-releasing agent as described in British patent GB-A 1,211,860.
Dans le cas où le tuyau produit n'est pas appelé à devoir résister à des conditions d'utilisation sévères, la matière thermoplastique constitutive de l'âme peut avantageusement être obtenue à partir de matières thermoplastiques recyclées et notamment de déchets d'emballages tels que des bouteilles. In the case where the pipe produced is not called upon to have to withstand severe conditions of use, the thermoplastic material constituting the core can advantageously be obtained from recycled thermoplastic materials and in particular packaging waste such as bottles.
De préférence, on choisit les matières thermoplastiques constitutives des parois et de l'âme de façon telle que celles-ci soient compatibles afin d'obtenir une adhérence suffisante entre les couches constituant le tuyau allégé. On peut toutefois réaliser des tuyaux allégés à partir de matières thermoplastiques non compatibles en prévoyant une ou des couches d'un adhésif thermoplastique approprié entre les couches non compatibles, ce qui impose naturellement le recours à une tête de répartition à quatre, voire cinq couches. Preferably, the thermoplastic materials constituting the walls and the core are chosen so that they are compatible in order to obtain sufficient adhesion between the layers constituting the lightened pipe. However, lightweight pipes can be made from non-compatible thermoplastic materials by providing one or more layers of a suitable thermoplastic adhesive between the non-compatible layers, which naturally requires the use of a distribution head with four or even five layers.
La présente invention a également pour objet de fournir une filière qui convient particulièrement pour la réalisation de ce procédé. The present invention also aims to provide a die which is particularly suitable for carrying out this process.
L'invention concerne donc également une filière comportant un convergent-divergent et une portion droite de conformation du tuyau qui se caractérise en ce que la portion droite de conformation du tuyau, en amont de l'orifice de sortie, présente une zone de section rétrécie. The invention therefore also relates to a die comprising a convergent-divergent and a straight portion of pipe shaping which is characterized in that the straight portion of pipe shaping, upstream of the outlet orifice, has a region of narrowed section .
De préférence, dans la filière conforme à l'invention, le rapport entre la section de l'orifice de sortie et la section de la zone de section rétrécie est compris entre 1,5 et 5. Preferably, in the die according to the invention, the ratio between the section of the outlet orifice and the section of the region of narrowed section is between 1.5 and 5.
Selon un mode de réalisation particulier de la filière conforme à l'invention, la zone de section rétrécie est constituée par un accroissement du diamètre interne de la section de passage de la portion droite de conformation. According to a particular embodiment of the die according to the invention, the narrowed section area is constituted by an increase in the internal diameter of the passage section of the straight shaping portion.
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CH 680 659 A5 CH 680 659 A5
Selon un autre mode de réalisation, la zone de section rétrécie est constituée par une diminution du diamètre externe de la section de passage de la portion droite de conformation. According to another embodiment, the narrowed section area is constituted by a reduction in the external diameter of the passage section of the straight shaping portion.
Il est toutefois évident que la zone de section rétrécie peut être constituée à la fois par un accroissement et par une diminution des diamètres interne et externe de la section de passage de la portion droite de conformation. It is however obvious that the narrowed section zone can be constituted both by an increase and by a decrease in the internal and external diameters of the passage section of the straight portion of conformation.
Pour éviter tout risque de stagnation de matière thermoplastique, il convient que l'accroissement et/ou la diminution des diamètres interne et externe de la section de passage de la portion droite de conformation soient réalisés de façon progressive et, de préférence, selon une pente de 5 à 15°. To avoid any risk of stagnation of thermoplastic material, the increase and / or decrease in the internal and external diameters of the passage section of the straight shaping portion should be carried out gradually and, preferably, along a slope from 5 to 15 °.
De façon avantageuse, la zone de section rétrécie a une longeur comprise entre 5 et 20 cm. Advantageously, the narrowed section area has a length of between 5 and 20 cm.
En outre, ia distance entre la zone de section rétrécie et l'orifice de sortie de la portion droite de conformation est d'au moins 5 cm de façon à assurer la formation d'un tuyau allégé ayant l'épaisseur de paroi désirée nonobstant la présence de la zone de section rétrécie. In addition, the distance between the region of narrowed section and the outlet of the straight shaping portion is at least 5 cm so as to ensure the formation of a lighter pipe having the desired wall thickness notwithstanding the presence of the narrowed section area.
Le procédé et la filière selon l'invention sont en outre explicités de façon plus détaillée dans les exemples de réalisation pratique qui vont suivre et pour lesquels on se référera à la figure du dessin annexé qui représente en coupe partielle schématique le canal d'écoulement des matières thermoplastiques dans une filière conforme à l'invention. The method and the die according to the invention are further explained in more detail in the practical examples which follow and for which reference is made to the figure of the appended drawing which represents in schematic partial section the flow channel of the thermoplastics in a die according to the invention.
Ainsi qu'il apparaît sur cette figure, la filière conforme à l'invention dont la partie arrière 1 est raccordée à une tête de répartition non représentée comporte un divergent 2 et un convergent 3 reliés entre eux via un trèfle 4 comportant les ailettes maintenant le noyau 5 et une portion droite 6 de conformation du tuyau, cette portion ayant une longueur Lo et une épaisseur de passage e0. As it appears in this figure, the die according to the invention, the rear part 1 of which is connected to a distribution head, not shown, comprises a diverging part 2 and a converging part 3 connected together via a clover 4 comprising the fins holding the core 5 and a straight portion 6 of conformation of the pipe, this portion having a length Lo and a passage thickness e0.
Conformément à l'invention, la portion droite 6 comporte une zone 7 de longueur L et d'épaisseur e de section rétrécie qui est obtenue par un accroissement du diamètre interne de la section de passage de la portion droite de conformation 6. En outre, la zone de section rétrécie 7 est raccordée progressivement à la paroi interne de la portion droite 6 de conformation selon des pentes 8 de 10°. In accordance with the invention, the straight portion 6 comprises an area 7 of length L and thickness e of narrowed section which is obtained by increasing the internal diameter of the passage section of the straight portion of conformation 6. In addition, the narrowed section zone 7 is gradually connected to the internal wall of the straight portion 6 of conformation according to slopes 8 of 10 °.
Dans une filière de grand diamètre (supérieur à 25 cm) telle que représentée à la figure susdécrite mais dépourvue de zone 7 de section rétrécie, la pression d'extrusion générée dans la portion droite de conformation peut être calculée par la relation: In a large diameter die (greater than 25 cm) as shown in the above-mentioned figure but devoid of zone 7 of narrowed section, the extrusion pressure generated in the straight portion of conformation can be calculated by the relation:
XT *n o XT * n o
AP = K y AP = K y
' e o 'e o
dans laquelle: in which:
- y est le gradient de vitesse développé dans la géométrie initiale d'épaisseur e0 et de longueur Lo," - y is the velocity gradient developed in the initial geometry of thickness e0 and of length Lo, "
- n est le coefficient non newtonien calculé au départ de la relation: - n is the non-Newtonian coefficient calculated at the start of the relation:
t = K 7° t = K 7 °
- T étant la tension de cisaillement de la matière thermo-plastique mise en œuvre au gradient de vitesse Y et - T being the shear stress of the thermoplastic material used at the speed gradient Y and
- K étant une constante obtenue au départ de la relation précédente. - K being a constant obtained at the start of the previous relation.
Exemples Examples
Dans les exemples qui vont suivre, on a, pour des raisons de facilité, réalisé les tubes allégés uniquement à partir de polychlorure de vinyle de nombre K = 66 contenant 2,1 per de stabilisant au plomb, 0,5 per de lubrifiant interne et 0,5 per de lubrifiant externe. In the examples which follow, for the sake of convenience, the lightened tubes were produced only from polyvinyl chloride of number K = 66 containing 2.1 per cent of lead stabilizer, 0.5 per cent of internal lubricant and 0.5 per cent of external lubricant.
Les propriétés rhéologiques de cette composition ont été mesurées au moyen d'un viscosimètre à capillaire INSTRON® équipé de filières cylindriques de 0,2 cm de diamètre et de rapport L/R de 1 et 30 respectivement, donnant un même gradient de vitesse y et respectivement les pressions d'extrusion Pi et Pz. La tension de cisaillement se calcule au moyen de la relation classique: The rheological properties of this composition were measured using an INSTRON® capillary viscometer equipped with cylindrical dies of 0.2 cm in diameter and L / R ratio of 1 and 30 respectively, giving the same speed gradient y and respectively the extrusion pressures Pi and Pz. The shear stress is calculated using the classical relation:
1 1
T - (Po-Pi) • • 98100 Pa T - (Po-Pi) • • 98100 Pa
2(30-1) 2 (30-1)
(Pi et Pz étant mesurées en kg/cm2). (Pi and Pz being measured in kg / cm2).
Pour la formulation mise en œuvre, les paramètres rhéologiques mesurés sont: For the formulation used, the rheological parameters measured are:
-K = 2.104 — n = 0,55. -K = 2.104 - n = 0.55.
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CH 680 659 A5 CH 680 659 A5
Exemple 1 Me référence^ Example 1 Refer to me ^
Pour cet essai, donné à titre de comparaison, on a utilisé une filière telle qu'illustrée dans la figure annexée mais dépourvue de zone rétrécie dans la portion droite de conformation, la filière étant raccordée à une tête de répartition. For this test, given by way of comparison, a die was used as illustrated in the appended figure but devoid of a narrowed region in the straight shaping portion, the die being connected to a distribution head.
Les paramètres géométriques de cette filière dans la portion droite de conformation sont les suivants: The geometrical parameters of this die in the right portion of conformation are the following:
-diamètre = 315 mm - diameter = 315 mm
- Lo = 34,6 cm - Lo = 34.6 cm
- e0 = 8,85 mm. - e0 = 8.85 mm.
Avec cet appareillage, on extrude la composition définie ci-avant sous un débit de 400 kg par heure, la température de la filière étant de 185°C et la température de la matière thermoplastique à la sortie de 189°C. With this apparatus, the composition defined above is extruded at a rate of 400 kg per hour, the temperature of the die being 185 ° C. and the temperature of the thermoplastic material at the outlet of 189 ° C.
La pression développée par la filière utilisée au niveau du convergent est égale à: The pressure developed by the sector used at the converging point is equal to:
2.34,6 2.34.6
K K
0,885 0.885
dans laquelle: in which:
6 x 400 6 x 400
y = = 7,05. y = = 7.05.
3,6 x 1,24 x 3,14 x 31 x 0,8852 3.6 x 1.24 x 3.14 x 31 x 0.8852
On trouve dès lors que la pression développée dans le convergent est égale à 4,6.106 Pascals. On constate que le tube allégé extrudé dans ces conditions présente des marques longitudinales provenant de la présence des ailettes porte-noyau, ces marques constituant des points de faiblesse en cas de choc. We therefore find that the pressure developed in the convergent is equal to 4.6.106 Pascals. It can be seen that the lightened tube extruded under these conditions has longitudinal marks originating from the presence of the core-carrying fins, these marks constituting points of weakness in the event of impact.
Exemple 2 Example 2
On procède comme à l'exemple 1 en utilisant une filière identique mais équipée cette fois d'une zone rétrécie dans la portion droite de conformation comme illustrée sur la figure annexée. The procedure is as in Example 1 using an identical die but this time equipped with a narrowed zone in the straight portion of conformation as illustrated in the appended figure.
La longueur de la zone rétrécie est de 79 mm et le passage laissé libre dans cette zone a une épaisseur de 4,35 mm. The length of the narrowed area is 79 mm and the passage left free in this area has a thickness of 4.35 mm.
Le gradient de vitesse au niveau de la zone rétrécie est dès lors de 30 sec-1. The speed gradient at the narrowed area is therefore 30 sec-1.
La pression qui en résulte au niveau du convergent est dès lors de: The resulting pressure at the converging point is therefore:
2.10^ x 7,05°'55 x 7,9 x 2 4,6,10® Pascals — -—Pascals + 2.10 ^ x 7.05 ° '55 x 7.9 x 2 4,6,10® Pascals - -—Pascals +
0,885 0.885
2.101* x 30°>55 x 7,9 x 2 2.101 * x 30 °> 55 x 7.9 x 2
———————— Pascals = 4,6.10® Pascals - ———————— Pascals = 4,6.10® Pascals -
0,435 0.435
1,05.106 Pascals + 4,7.106 Pascals = 8,25.106 Pascals, 1.05.106 Pascals + 4.7.106 Pascals = 8.25.106 Pascals,
ce qui représente une pression supérieure de 3,65.106 Pa à celle développée selon l'exemple 1. On constate cette fois que le tuyau allégé produit est exempt de tout défaut. which represents a higher pressure of 3.65.106 Pa than that developed according to Example 1. This time, it can be seen that the lightened pipe produced is free from any defect.
Claims (7)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8809125A FR2633554B1 (en) | 1988-07-04 | 1988-07-04 | METHOD FOR PRODUCING, BY COEXTRUSION, AN LIGHTWEIGHT PIPE AND DIE FOR ITS PRODUCTION |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CH680659A5 true CH680659A5 (en) | 1992-10-15 |
Family
ID=9368123
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CH2259/89A CH680659A5 (en) | 1988-07-04 | 1989-06-16 |
Country Status (10)
| Country | Link |
|---|---|
| AT (1) | AT403778B (en) |
| BE (1) | BE1006667A3 (en) |
| CH (1) | CH680659A5 (en) |
| DE (1) | DE3921853C2 (en) |
| ES (1) | ES2015163A6 (en) |
| FR (1) | FR2633554B1 (en) |
| GB (1) | GB2220165B (en) |
| IT (1) | IT1230889B (en) |
| NL (1) | NL195010C (en) |
| PT (1) | PT91013B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6827888B2 (en) | 2001-01-23 | 2004-12-07 | Genpak Llc | Polymeric foam sheet using ambient gas blowing agent via controlled expansion |
| CN102001173B (en) * | 2010-12-02 | 2013-06-05 | 铜陵三佳科技股份有限公司 | Co-extrusion die head for extruding profiled bars with co-extrusion surface |
| CN102922723A (en) * | 2012-11-08 | 2013-02-13 | 苏州金纬机械制造有限公司 | Molding pipe split-flow mold |
| CN106827449B (en) * | 2017-01-20 | 2022-11-25 | 广东科志达机械科技有限公司 | Film blowing device of film blowing machine |
Family Cites Families (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL106764C (en) * | 1956-03-22 | 1900-01-01 | ||
| GB1128809A (en) * | 1965-10-28 | 1968-10-02 | Monsanto Chemicals | Foamed resins |
| US3497915A (en) * | 1967-03-16 | 1970-03-03 | Cupples Container Co | Extrusion die |
| US3525125A (en) * | 1967-07-12 | 1970-08-25 | Basf Ag | Annular die for extruders,particularly an annular die for the production of blown tubular film and sheeting from expandable thermoplastics |
| GB1211860A (en) * | 1967-10-03 | 1970-11-11 | Ici Ltd | A process for the production of pipe |
| FR2130735A5 (en) * | 1970-05-29 | 1972-11-10 | Armosig | |
| FR2139626B3 (en) * | 1971-05-26 | 1973-05-25 | Armosig | |
| DE2126976A1 (en) * | 1970-05-29 | 1972-01-20 | Armosig | Extrusion press - with section of constant diameter to allow foaming action to stabilise |
| US3899276A (en) * | 1973-05-29 | 1975-08-12 | Beloit Corp | Annular extrusion die with back pressure control |
| US4057610A (en) * | 1975-07-25 | 1977-11-08 | Monsanto Company | Hose reinforced with discontinuous fibers oriented in the radial direction |
| DE2610972C2 (en) * | 1976-03-16 | 1984-04-12 | Erich 7326 Heiningen Oprach | Device for the production of pipes or similar hollow strands made of thermoplastic material |
| FR2427897A1 (en) * | 1978-06-09 | 1980-01-04 | Pont A Mousson | Pipe extrusion die allowing sudden wall thickness variation - by adjustment of the melt volume of a die receiving melt at a constant rate |
| FR2455972A1 (en) * | 1979-05-10 | 1980-12-05 | Sogecan Ste Gle Canalisations | PROCESS AND APPARATUS FOR THE EXTRUSION OF PLASTIC TUBES WITH COMPOSITE WALLS |
| FR2494180A1 (en) * | 1980-11-19 | 1982-05-21 | Comp Generale Electricite | Making plastic profiles or sheet - with enhanced transverse thermal conductivity, by extrusion via an annular choke to reorientate conductive fillers |
| DE3233250A1 (en) * | 1982-09-08 | 1984-03-08 | Basf Ag, 6700 Ludwigshafen | DEVICE FOR EXTRUDING THERMOPLASTIC PLASTICS |
-
1988
- 1988-07-04 FR FR8809125A patent/FR2633554B1/en not_active Expired - Fee Related
-
1989
- 1989-06-16 CH CH2259/89A patent/CH680659A5/fr not_active IP Right Cessation
- 1989-06-19 AT AT0149589A patent/AT403778B/en not_active IP Right Cessation
- 1989-06-21 IT IT8920940A patent/IT1230889B/en active
- 1989-06-26 GB GB8914629A patent/GB2220165B/en not_active Expired - Fee Related
- 1989-06-28 BE BE8900711A patent/BE1006667A3/en not_active IP Right Cessation
- 1989-06-29 PT PT91013A patent/PT91013B/en not_active IP Right Cessation
- 1989-07-03 NL NL8901687A patent/NL195010C/en not_active IP Right Cessation
- 1989-07-03 DE DE3921853A patent/DE3921853C2/en not_active Expired - Fee Related
- 1989-07-03 ES ES8902346A patent/ES2015163A6/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| ES2015163A6 (en) | 1990-08-01 |
| GB8914629D0 (en) | 1989-08-16 |
| GB2220165B (en) | 1992-07-01 |
| FR2633554B1 (en) | 1990-10-19 |
| DE3921853A1 (en) | 1990-01-11 |
| BE1006667A3 (en) | 1994-11-16 |
| DE3921853C2 (en) | 1999-04-08 |
| AT403778B (en) | 1998-05-25 |
| IT8920940A0 (en) | 1989-06-21 |
| NL195010C (en) | 2003-06-10 |
| FR2633554A1 (en) | 1990-01-05 |
| IT1230889B (en) | 1991-11-08 |
| PT91013B (en) | 1994-06-30 |
| ATA149589A (en) | 1997-10-15 |
| PT91013A (en) | 1990-02-08 |
| GB2220165A (en) | 1990-01-04 |
| NL8901687A (en) | 1990-02-01 |
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Legal Events
| Date | Code | Title | Description |
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| PFA | Name/firm changed |
Owner name: SOLVAY (SOCIETE ANONYME) |
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| PL | Patent ceased |