EP1140453A1 - Procede de moulage rotatif et appareil correspondant - Google Patents
Procede de moulage rotatif et appareil correspondantInfo
- Publication number
- EP1140453A1 EP1140453A1 EP99961253A EP99961253A EP1140453A1 EP 1140453 A1 EP1140453 A1 EP 1140453A1 EP 99961253 A EP99961253 A EP 99961253A EP 99961253 A EP99961253 A EP 99961253A EP 1140453 A1 EP1140453 A1 EP 1140453A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- mould
- activator
- polymer
- polymerisation
- thermoplastic
- 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- Withdrawn
Links
- 238000001175 rotational moulding Methods 0.000 title claims description 25
- 239000012190 activator Substances 0.000 claims abstract description 66
- 238000000034 method Methods 0.000 claims abstract description 60
- 229920001169 thermoplastic Polymers 0.000 claims abstract description 30
- 239000004416 thermosoftening plastic Substances 0.000 claims abstract description 30
- 229920001730 Moisture cure polyurethane Polymers 0.000 claims abstract description 24
- 239000000203 mixture Substances 0.000 claims abstract description 21
- 150000003951 lactams Chemical class 0.000 claims abstract description 20
- 239000012298 atmosphere Substances 0.000 claims abstract description 17
- 238000000465 moulding Methods 0.000 claims abstract description 12
- 239000000376 reactant Substances 0.000 claims abstract description 10
- 239000000463 material Substances 0.000 claims description 24
- 238000010438 heat treatment Methods 0.000 claims description 16
- 239000000945 filler Substances 0.000 claims description 12
- 238000002347 injection Methods 0.000 claims description 11
- 239000007924 injection Substances 0.000 claims description 11
- 238000001816 cooling Methods 0.000 claims description 9
- 238000002156 mixing Methods 0.000 claims description 5
- 238000010926 purge Methods 0.000 claims description 4
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 3
- 229920001577 copolymer Polymers 0.000 claims description 3
- 239000000155 melt Substances 0.000 claims description 3
- 239000012299 nitrogen atmosphere Substances 0.000 claims description 3
- 239000004417 polycarbonate Substances 0.000 claims description 3
- 229920000515 polycarbonate Polymers 0.000 claims description 3
- UHZZMRAGKVHANO-UHFFFAOYSA-M chlormequat chloride Chemical compound [Cl-].C[N+](C)(C)CCCl UHZZMRAGKVHANO-UHFFFAOYSA-M 0.000 claims description 2
- 239000006185 dispersion Substances 0.000 claims description 2
- 238000011010 flushing procedure Methods 0.000 claims description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 15
- 239000007788 liquid Substances 0.000 description 10
- 239000008188 pellet Substances 0.000 description 9
- 229910052757 nitrogen Inorganic materials 0.000 description 7
- JHWNWJKBPDFINM-UHFFFAOYSA-N Laurolactam Chemical compound O=C1CCCCCCCCCCCN1 JHWNWJKBPDFINM-UHFFFAOYSA-N 0.000 description 5
- 229920000299 Nylon 12 Polymers 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 239000012815 thermoplastic material Substances 0.000 description 3
- 230000002411 adverse Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- JBKVHLHDHHXQEQ-UHFFFAOYSA-N epsilon-caprolactam Chemical compound O=C1CCCCCN1 JBKVHLHDHHXQEQ-UHFFFAOYSA-N 0.000 description 2
- 239000008187 granular material Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 239000002861 polymer material Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229920002292 Nylon 6 Polymers 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005297 material degradation process Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000011325 microbead Substances 0.000 description 1
- 239000004005 microsphere Substances 0.000 description 1
- 239000003595 mist Substances 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- -1 polyethylene Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 239000002952 polymeric resin Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000454 talc Substances 0.000 description 1
- 229910052623 talc Inorganic materials 0.000 description 1
- 230000001960 triggered effect Effects 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
- B29C41/00—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
- B29C41/02—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor for making articles of definite length, i.e. discrete articles
- B29C41/04—Rotational or centrifugal casting, i.e. coating the inside of a mould by rotating the mould
-
- 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
- B29C41/00—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
- B29C41/003—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor characterised by the choice of 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
- B29C2791/00—Shaping characteristics in general
- B29C2791/004—Shaping under special conditions
- B29C2791/005—Using a particular environment, e.g. sterile fluids other than air
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C31/00—Handling, 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
- B29C31/04—Feeding of the material to be moulded, e.g. into a mould cavity
- B29C31/06—Feeding of the material to be moulded, e.g. into a mould cavity in measured doses, e.g. by weighting
-
- 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
- B29C41/00—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
- B29C41/02—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor for making articles of definite length, i.e. discrete articles
- B29C41/04—Rotational or centrifugal casting, i.e. coating the inside of a mould by rotating the mould
- B29C41/06—Rotational or centrifugal casting, i.e. coating the inside of a mould by rotating the mould about two or more axes
-
- 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
- B29K2077/00—Use of PA, i.e. polyamides, e.g. polyesteramides 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
- B29K2105/0002—Condition, form or state of moulded material or of the material to be shaped monomers or prepolymers
Definitions
- the invention relates to rotational moulding.
- Rotomoulding is an inexpensive process that is widely used for manufacturing hollow plastics components.
- a polymer resin in a powder form is introduced into a hollow mould which is heated externally in a large oven.
- the mould is biaxially rotated as the powder sinters and the plastic coats the interior surface of the mould relatively evenly, typically to a thickness greater than 3 mm.
- Such conventional rotomoulding has the advantages of relatively low capital equipment costs, inexpensive tooling as there is no pressure applied, and allows large volume complex shapes to be easily moulded.
- thermoplastic materials have become available which have potential advantages of improved mechanical strength, toughness, low water absorption, high softening temperature and relatively low cost.
- thermoplastics melt in the mould According to the invention there is provided a method of rotomoulding comprising the step of forming a reactant thermoplastics melt in the mould.
- the reactant thermoplastics melt comprises a mixture of a thermoplastic pre-polymer and a polymerisation activator.
- thermoplastics pre-polymer and the polymerisation activator may be mixed in the mould.
- thermoplastics pre-polymer and the polymerisation activator are mixed prior to delivery into a mould.
- the mixing and preferably also the moulding is carried out under an inert atmosphere.
- the inert atmosphere is typically a nitrogen atmosphere.
- the pre-polymer and polymerisation activator are mixed to form a pre-mix which is stored in a holding container prior to delivery into the mould.
- the mixture is added to the mould at ambient temperature conditions.
- the mixture is introduced into the mould under an inert atmosphere.
- the mould is heated to polymerisation temperature.
- the mould is rotated, usually biaxially, typically at a speed of greater than 5 r.p.m.
- the method comprises the steps of: - delivering a thermoplastics pre-polymer into the mould; and
- thermoplastic pre-polymer in the mould introducing a polymerisation activator to the thermoplastic pre-polymer in the mould.
- the polymerisation activator may be introduced into the mould separately from the pre-polymer.
- the polymerisation activator may be injected into the mould to form a reactant melt in the mould.
- thermoplastic pre-polymer placing the thermoplastic pre-polymer in a mould
- the method comprises the steps of: -
- thermoplastic pre-polymer placing thermoplastic pre-polymer in a mould
- the mould is pre-heated to a temperature of from ambient temperature to 170°C, preferably to a temperature of approximately 170°C.
- the mould after injection of the activator, is further heated to a temperature of from 170°C to 205°C over a period of from 5 to 10 minutes.
- the mould is further heated to a temperature of about 200°C over a period of about 10 minutes to ensure complete polymerisation.
- the activator line is purged after injection of the activator.
- the method includes the step of rotating the mould during preheating.
- the method includes the step of rotating the mould after injection of the activator to dissolve or disperse the activator in the preheated melt.
- the mould is preferably rotated biaxially after dispersion of the activator in the melt.
- the biaxial rotation is usually at a speed of greater than 5 rpm.
- thermoplastic is selected from one or more of PBT, ABS, acrylic, polycarbonate, lactam, mixtures, blends or copolymers thereof.
- thermoplastic is a lactam material.
- activator is preferably an activator for producing an ionically polymerised lactam.
- the lactam is lactam-12.
- the invention also provides a rotomoulding apparatus including a mould having an injector means for injecting an activator into the mould for in-mould reactive moulding.
- the apparatus includes a flush means for flushing the injector after injection of the activator into the mould.
- the mould used in the method of the invention has integral mould heating and cooling means.
- the rotation speeds during rotomoulding may be changed from an initially high speed when the liquid has a low viscosity to lower speeds as the viscosity of the matrix within the mould increases.
- Nitrogen flush is maintained throughout to ensure polymerisation and to reduce oxidation and material degradation.
- the invention further provides a rotomoulded article whenever produced using the apparatus and/or method of the invention.
- Figs 1 to 5 are schematic views illustrating the various steps in a process According to one embodiment of the invention.
- Figs 6 to 11 are schematic views illustrating steps in a process according to another embodiment of the invention. Detailed Description
- the method and apparatus for rotomoulding used in the invention employs a system with improved control of the mould temperature. This facilitates a high level of repeatability and traceability.
- a gimbal-type aluminium framed biaxial rotomoulding machine may be used to provide full biaxial rotation.
- the mould may be heated by infra-red.
- a composite tool with embedded heating wires and cooling channels may be used.
- One such system is described in WO-A-961496.
- a reactant thermoplastics melt is formed in the mould rather than outside the mould.
- This has processing advantages especially in overcoming difficulties in handling the separate monomeric and activator materials. In this case they are kept separate and are only mixed in the mould so that in mould polymerisation of the material takes place. This is easy to control because the material can be kept in motion in the mould and the temperature is readily controlled in the mould. Thus, an even and reproducible polymerisation and moulding can be achieved.
- Granules/pellets of lactam-12 are first placed in a mould 1 at room temperature.
- the mould 1 is then pre-heated to approximately 170°C to melt the lactam-12.
- the mould is preferably rotated during pre-heating to maximise exposure of pellets to the hot surface of the mould.
- a polymerisation activator is then injected directly into the mould through an atomiser/injector 2 fitted with a Nitrogen purge.
- the activator is efficiently dispersed into the molten lactam-12 and in- mould polymerisation is initiated.
- the mould is preferably rotated around one or two axes on introduction of the activator to efficiently dissolve or disperse the activator in the melt.
- the activator may be introduced using a piston driven pneumatic actuator or a dosing pump with a separate reservoir mounted on the moulding machine. This facilitates controlled delivery of activator, on demand.
- An atomiser head forms a fine mist of activator droplets for rapid mixing.
- the temperature of the mould is increased to about 200°C over a period of about 10 minutes to complete the polymerisation process.
- the material evenly adheres to the mould forming a moulded article 3 of desired thickness, especially thin walled articles.
- the lactam and activator are easily handled.
- the reactive rotational moulding technique is more easily controlled, is faster, can produce a wider range of moulded articles, especially thin walled articles, and lends itself to automation leading to at lest semi-continuous operation.
- An inert atmosphere for example provided by nitrogen, is provided in the cavity of the mould to exclude moisture.
- Re-fillable supply cylinders may be mounted to the mould by a system of valves and regulators to control the flow of gas into the mould.
- a pre -weighed amount of lauralactam pellets (the monomer form of Nylon- 12) is placed within the mould 1 e.g. 1.25 kg.
- a pre-weighed amount of liquid activator is dispensed into a syringe container and placed in the mounting fixture on the mould.
- the amount is typically 1.5% by weight of the pre-defined weight of lauralactam pellets being processed e.g. 18.75 ml for 1.25 kg of lauralactam.
- the mould breather device encompassing nitrogen flush tube activator dispensing needle, atomiser head and breather exhaust is inserted into the mould.
- N 2 flush is provided for the activator dispensing system to maintain an N 2 atmosphere in the mould and to purge all the activator from the dispensing system after dispensing.
- the mould is closed to form a water-tight seal between both halves.
- a nitrogen flush maintains a slight positive pressure (0.05 bar) within the mould of nitrogen gas. This is to (a) purge any air/ moisture within the mould which could adversely affect polymerisation, (b) keep the atomiser head free of any condensed lactam material and, c) to clean atomiser head after injection of activator.
- the heating cycle commences which heats the mould using embedded resistance heating wires.
- the mould heats to a typical set point temperature of 170°C
- the lactam pellets also heat up and begin to melt.
- a large surface area of the mould improves heat transfer and reduces the time required for complete melting of the pellets. Rotation of the mould during pre-heating also ensures uniform and efficient melting of the pellets.
- a slow rotation speed of typically 3 rpm on the major axis, 3 rpm on the minor axis is used to distribute the pellets on the inside of the mould as illustrated in Fig. 2.
- the lactam pellets have fully melted out to form a liquid with a viscosity similar to that of water.
- the rotomoulding machine comes to a halt in the vertical plane.
- the rotation speed in the horizontal is increased to promote shearing motion of the liquid , which now forms a pool on the bottom of the mould.
- a pneumatic ram is triggered which forces the liquid activator out through a syringe, through the dispensing needle and atomiser head and into the mould.
- the force applied is regulated by the speed of the ram pushing the syringe.
- the atomiser head causes the activator to disperse into a cone of minute droplets which drop over the surface of the liquid pool.
- the combination of the fine activator droplets and the motion of the liquid mean that intimate mixing occurs almost immediately and does not give the activator time to coalesce on the surface of the mould.
- the injection time is in the order of 10-15 seconds.
- the nitrogen flush is used to clean the dispensing needle and atomiser head of any remaining liquid activator.
- Biaxial rotation re-commences after the activator is injected at a speed of typically greater than 5 rpm on the major and minor axes. This is to create the conditions for the phenomenon of solid body rotation of the molten mass. As the viscosity increases on polymerisation, the speed of rotation may be reduced to maintain solid body rotation and to reduce centrifugal effects and uneven thickness build up.
- the mould set point temperature is increased to 205°C (typical value, internal face temperature). This takes approximately 5-7 minutes to achieve. The higher temperature is required to reduce the time for polymerisation. After a sufficient period of time (typically 5-7 minutes to reach temperature, 10 minutes at temperature), the rotation speeds of both axes are reduced by a factor of 50% (typically). This is to account for the rapidly increasing viscosity of the nylon- 12 material within the mould. After another 5 minutes, the heaters are turned off and forced air convection cooling commences.
- 205°C typically value, internal face temperature
- Cooling takes approximately 15 minutes to reduce the temperature from 205°C to part removal temperature (typically 80°C).
- the mould can them be opened, the breather device withdrawn and the moulded nylon-12 part removed.
- FIG. 6 there is illustrated another method of rotomoulding according to the invention.
- Granules 10 of a thermoplastic material such as the lactam material described above are in this case mixed with a polymerisation activator 11 in a premix vessel 12.
- the vessel 12 is a sealed vessel with a suitable mixer 13 for mixing the activator 11 and thermoplastics 10 under an inert atmosphere.
- the vessel 12 has a bottom outlet closed by a valve 15, in this case a flap valve.
- the premix thus formed is loaded into containers such as a bag 16 (Fig 7) under an inert atmosphere.
- the bag of premixed material is sealed and may be stored until required.
- a mould 20 When it is desired to mould a product using the premix a mould 20 is opened and under an inert atmosphere and at room temperature the premix is introduced into the mould 20. If desired, the premix is rotated biaxially in the mould (Fig. 9) and - li the temperature of the mould 20 is increased to polymerise the thermoplastic mixture. Typically the temperature is increased by heating the mould walls by imbedded resistance wires to achieve about 205°C on the internal face of the mould. This takes about 10 minutes.
- biaxial rotation continues at a speed of typically greater than 5 rpm on the major and minor axes. This is to create the conditions for the phenomenon of solid body rotation of the molten mass. As the viscosity increases on polymerisation, the speed of rotation may be reduced to maintain solid body rotation and to reduce centrifugal effects and uneven thickness build up.
- Cooling takes approximately 15 minutes to reduce the temperature from 205°C to part removal temperature (typically 80°C).
- the mould 20 can then be opened, the breather device withdrawn and a moulded part 21 removed.
- the process described with reference to Figs 6 to 11 is particularly advantageous as the premix is formed before being introduced into the mould.
- the introduction into the mould can be carried out at ambient conditions.
- the premix is readily prepared and can be stored under an inert atmosphere.
- the invention provides an integrated process and apparatus for at least semi- continuous rotomoulding. Multiple moulds may be provided on a single machine. If desired, a number of separate moulds may be arranged at separate stations for delivery of pre-polymer material.
- the stations may, for example, be arranged around a central dispensing unit or may be arranged in-line.
- a control system may be operated to deliver the pre-polymer material on demand by the individual rotomoulding stations.
- initial rotation speeds may be relatively high to ensure that a skin of uniform thickness is formed in the mould cavity before the viscosity increases, on polymerisation.
- This has the advantage that potentially thin walled products may be readily rotationally moulded.
- the moulding machine technology used allows the injection of other material into the mould cavity after the outer skin has formed.
- polyethylene foam may be injected into the mould cavity.
- the low viscosity of the lactam facilitates the forming of very fine details, such as screw threads and the like.
- Internal pressurisation and/or forced circulation of cooled air/ N 2 to improve cooling efficiency is preferably maintained during cooling to reduce adverse warpage and shrinkage effects.
- a batch of 1kg lactam is placed in a container and a vacuum is applied.
- An inert atmosphere is introduced by nitrogen.
- the container is opened while maintaining the inert atmosphere and an amount of about 15g of an activator which is typically in a liquid form is added.
- the container is closed and the contents are mechanically agitated to disperse the activator in the lactam.
- the premix thus formed can be stored indefinitely in an inert atmosphere.
- the prepared premix is dispersed into the mould, air is purged from the mould and the moulding process is carried out as described above.
- the premix may include a filler which may be present in an amount of from 10 to 70% by volume.
- the filler may be of a ceramic material, glass, talc or any suitable inert material. It may be in the form of particulates, microbeads, microspheres or fibres.
- the filler is added to the premix under an inert atmosphere.
- the advantages of using such fillers are lower costs, enhanced properties and improved processing.
- the fillers increase viscosity and reduce flow instability on flow allowing for more even wall thicknesses.
- Fillers in formulations for rotational moulding can be accommodated because, in addition to the premixing described above the rotational moulding process mixes and agitates the filler during processing to ensure homogenous distribution of the fillers in the final product.
- the use of a large hollow cavity facilitates the placement of materials with a relatively large bulk density into the mould to produce higher density material than with more conventional moulding where the entire cavity is filled with the material.
- Using filler materials generally involves increasing the processing temperatures by typically 10°C, depending on the type of and amount of filler used.
- thermoplastic material any suitable thermoplastic material.
- the material is a lactam-based prepolymer.
- a prepolymer may be laurylactam (Nylon 12), caprolactam (Nylon 6) or a blend of both at different ratios dependent on the final properties desired. In some cases a lower viscosity melt is obtained using such blends which is generally preferable if there are added fillers.
- the thermoplastic may also include or comprise one or more of PBT, ABS, acrylic, polycarbonate, lactam, mixture, blends or copolymers thereof.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Moulding By Coating Moulds (AREA)
Abstract
Selon cette invention, un procédé de moulage rotatif consiste à créer de la matière fondue thermoplastique réactive dans un moule (1, 20). La matière fondue thermoplastique réactive comprend un mélange d'un prépolymère thermoplastique tel que lactame (12) et un activateur de polymérisation. Le prépolymère et l'activateur peuvent être mélangés dans le moule sous atmosphère inerte; on peut aussi former le prémélange du prépolymère et de l'activateur avant de le diriger dans le moule (1). Le prémélange peut être stocké sous atmosphère inerte dans un récipient scellé tel qu'un sac (16) qui peut servir à le distribuer dans un moule (20) à température ambiante. En variante, on peut former de la matière fondue réactive dans le moule (1) en y acheminant le prépolymère puis en y injectant un activateur de polymérisation.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IE981100 | 1998-12-23 | ||
| IE981100 | 1998-12-23 | ||
| PCT/IE1999/000144 WO2000038897A1 (fr) | 1998-12-23 | 1999-12-23 | Procede de moulage rotatif et appareil correspondant |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP1140453A1 true EP1140453A1 (fr) | 2001-10-10 |
Family
ID=11041970
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP99961253A Withdrawn EP1140453A1 (fr) | 1998-12-23 | 1999-12-23 | Procede de moulage rotatif et appareil correspondant |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP1140453A1 (fr) |
| AU (1) | AU1794600A (fr) |
| WO (1) | WO2000038897A1 (fr) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6420047B2 (en) | 2000-01-21 | 2002-07-16 | Cyclics Corporation | Macrocyclic polyester oligomers and processes for polymerizing the same |
| US6960626B2 (en) | 2000-01-21 | 2005-11-01 | Cyclics Corporation | Intimate physical mixtures containing macrocyclic polyester oligomer and filler |
| US7151143B2 (en) | 2000-01-21 | 2006-12-19 | Cyclics Corporation | Blends containing macrocyclic polyester oligomer and high molecular weight polymer |
| US6906147B2 (en) | 2002-03-20 | 2005-06-14 | Cyclics Corporation | Catalytic systems |
| US7256241B2 (en) | 2000-01-21 | 2007-08-14 | Cyclics Corporation | Methods for polymerizing macrocyclic polyester oligomers using catalyst promoters |
| WO2002018476A2 (fr) | 2000-09-01 | 2002-03-07 | Cyclics Corporation | Methodes pour convertir des polyesters lineaires en compositions a base d'oligoester macrocyclique, et oligoesters macrocycliques |
| JP2005515965A (ja) | 2001-06-27 | 2005-06-02 | サイクリクス コーポレイション | 大環状オリゴエステルの単離、処方、および成形 |
| US7304123B2 (en) | 2001-06-27 | 2007-12-04 | Cyclics Corporation | Processes for shaping macrocyclic oligoesters |
| US6787632B2 (en) | 2001-10-09 | 2004-09-07 | Cyclics Corporation | Organo-titanate catalysts for preparing pure macrocyclic oligoesters |
| US6962968B2 (en) | 2002-12-20 | 2005-11-08 | Cyclics Corporation | Purification of macrocyclic oligoesters |
| FR2856625B1 (fr) * | 2003-06-27 | 2005-09-23 | Rhodia Engineering Plastics Sa | Fabrication d'articles par rotomoulage |
| FR2871091B1 (fr) * | 2004-06-03 | 2008-01-18 | Commissariat Energie Atomique | Procede de fabrication d'une vitesse d'etancheite d'un reservoir de type iv et reservoir de type iv |
| CN113561387A (zh) * | 2021-07-07 | 2021-10-29 | 浙江飞友康体设备有限公司 | 一种儿童滑梯部件滚塑装置及其工艺 |
| CN116141557B (zh) * | 2021-09-27 | 2025-11-11 | 陈强 | 一种气瓶内胆及其制备方法和应用 |
| CN115246189B (zh) * | 2022-06-29 | 2024-09-24 | 浙江瑞堂塑料科技有限公司 | 一种带除氧功能的通气管 |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE635595A (fr) * | 1962-08-03 | |||
| FR1519947A (fr) * | 1966-03-29 | 1968-04-05 | Allied Chem | Procédé de moulage d'objets creux de grandes dimensions en epsilon-caprolactame, dans des moules tournants |
| DE1795358A1 (de) * | 1968-09-19 | 1972-01-05 | Basf Ag | Verfahren und Vorrichtung zum Herstellen von Formkoerpern aus Polyamiden |
| DE2057709A1 (de) * | 1970-11-17 | 1972-05-31 | Mannesmann Ag | Behaelter oder Rohre aus Kunststoff zum Lagern bzw. zum Transport von Fluessigkeiten,Pasten oder rieselfaehigen Schuettguetern |
| CH544785A (de) * | 1971-02-11 | 1973-11-30 | Inventa Ag | Verfahren zur Herstellung von Formkörpern aus Polyamiden oder Copolyamiden |
| DE3406148A1 (de) * | 1984-02-21 | 1985-09-05 | Philips Patentverwaltung Gmbh, 2000 Hamburg | Verfahren zur herstellung von rohrfoermigen koerpern und vorrichtung zur durchfuehrung des verfahrens |
| US4671753A (en) * | 1985-08-19 | 1987-06-09 | Payne Leroy | Apparatus for molding |
| DE3818762A1 (de) * | 1988-06-02 | 1989-12-07 | Bayer Ag | Verfahren zur herstellung von duromeren kunststoffkoerpern mit inhomogener, dreidimensionaler brechungsindexverteilung |
-
1999
- 1999-12-23 EP EP99961253A patent/EP1140453A1/fr not_active Withdrawn
- 1999-12-23 WO PCT/IE1999/000144 patent/WO2000038897A1/fr not_active Ceased
- 1999-12-23 AU AU17946/00A patent/AU1794600A/en not_active Abandoned
Non-Patent Citations (1)
| Title |
|---|
| See references of WO0038897A1 * |
Also Published As
| Publication number | Publication date |
|---|---|
| AU1794600A (en) | 2000-07-31 |
| WO2000038897A1 (fr) | 2000-07-06 |
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