WO2017032615A1

WO2017032615A1 - Method for injection molding a reaction resin mixture and machine therefor

Info

Publication number: WO2017032615A1
Application number: PCT/EP2016/069194
Authority: WO
Inventors: Martin SCHNEEBAUER
Original assignee: Kraussmaffei Technologies Gmbh
Priority date: 2015-08-26
Filing date: 2016-08-12
Publication date: 2017-03-02
Also published as: DE102015114190A1

Abstract

The invention relates to a method for producing plastic injection moldings in at least one cavity (8) of an injection mold (4) from a polymeric reaction resin mixture which is injected into the cavity (8) by means of an extruder (9) and has a polymeric starting product, at least one activator and at least one optional catalyst. The invention also relates to an associated injection molding machine (1).

Description

METHOD FOR INJECTION MOLDING ONE

REACTION RESIN MIXTURE AND MACHINE THEREFOR

description

The invention relates to a method for producing plastic injection-molded parts in at least one cavity of an injection mold from an injected into the cavity by means of an extruder polymeric reaction resin mixture comprising a polymeric precursor, at least one activator and at least one optional catalyst. The invention also relates to an associated injection molding machine.

EP 2 572 851 A1 discloses a method for producing, in particular fiber-reinforced, thermoplastic plastic parts in an injection molding machine, the method comprising combining a polymeric precursor, an activator and a catalyst, and wherein the injection molding machine comprises a first plasticizing screw and a second plasticizing screw Plasticizing screw, which are each arranged in a plasticizing cylinder, wherein mixed with the first plasticizing the polymer precursor and the activator without adding the catalyst and are substantially liquefied and mixed with the second plasticizing screw, the polymeric precursor and the catalyst without addition of the activator and be substantially liquefied, after which the liquefied with the two Piastifizierschnecken contents are mixed and introduced together in an injection mold and polymerize there only to the plastic part ,

The object of the invention is to provide a method and an associated injection molding machine for the production of plastic injection molded polymer resin molded parts in which an improved reaction resin mixture comprising a polymeric precursor, at least one activator and at least one optional catalyst is provided to form a cavity an injection mold improved to produce plastic injection molded parts. The object is achieved by a method for producing plastic injection parts in at least one cavity of an injection mold from a polymer reaction resin mixture injected into the cavity by means of an extruder, comprising a polymeric precursor, at least one activator and at least one optional catalyst, comprising the steps:

Introducing the polymeric precursor into a feed zone of an extruder screw of the extruder,

Conveying the polymeric precursor from the feed zone into an injection zone of the extruder screw located downstream in the conveying direction of the extruder screw of the feed zone;

Injecting the at least one activator and the at least one optional catalyst from outside the extruder into the injection zone of the extruder screw in which the polymeric precursor is present,

Mixing the polymeric precursor with the injected at least one activator and with the injected at least one optional catalyst to a polymeric reaction resin mixture in a downstream in the conveying direction of the extruder screw of the injection zone mixing zone of the extruder screw and tempering the polymeric reaction resin mixture at a temperature below their reaction temperature,

Conveying the polymeric reaction resin mixture out of a downstream exit zone of the extruder in the conveying direction of the extruder screw into the injection mold, in particular into the cavity of the injection mold or into an antechamber of the injection mold,

Heating the polymeric reaction resin mixture in the cavity of the injection mold to the reaction temperature of the polymeric reaction resin mixture. The method can be used for producing single, two or multi-component plastic injection molded parts. The polymeric reaction resin mixture produced in accordance with the method can form a single component of the plastic injection molded part or, in the case of two- or multi-component plastic injection molded parts, two or more components of the plastic injection molded part can be formed by two or more, in particular different, polymeric reaction resin mixtures prepared according to the method. Depending on the number of different polymeric reaction resin mixtures to be used, a corresponding number of extruders according to the invention are to be used, which can be operated according to the method. The invention is representative of one or more polymeric reaction resin blends based on a single polymeric reaction resin blend. Polymeric reaction resin mixtures can be understood as meaning liquid or liquefiable synthetic resins which can be formed from a polymeric precursor, for example from a polyester resin, an epoxy resin, a methacrylate resin, a phenacrylate resin or a polyurethane, with the addition of at least one activator and / or an optional one catalyst. According to the invention, at least one activator within the extruder is to be added to the polymeric precursor. However, it is also possible to add two or more different activators as a mixture or in each case separately via a separate injection nozzle.

It is not always necessary to add a catalyst so that the processes according to the invention can be carried out either without a catalyst, ie only in conjunction with injecting at least one activator, or in conjunction with injecting at least one activator and at least one catalyst can be, the injection of the catalyst is therefore optional. The activator and the catalyst can be introduced into the extruder via separate, ie in each case separate, injection nozzles. The invention is described below with reference to the injection of an activator via a single injection nozzle. In the same way, however, the disclosure also applies to the injection of an additional catalyst. The polymeric precursor or the polymers Reaction resin mixture does not already have to be partly polymerized in the extruder or be completely polymerized, for example, but this may also mean that the precursor or the reaction resin mixture only has to be suitable for polymerizing in the cavity of the injection mold.

The polymeric precursor, the at least one activator and the at least one optional catalyst or polymeric reaction resin mixture or their mixed transitional forms in a per se known to those skilled in a conveying and mixing space between a screw cylinder of an extruder known as such and an extruder screw of the Extruder conveyed, mixed, compacted and heated. The extruder screw and / or the screw cylinder may have corresponding conveying elements and / or mixing or kneading and / or shearing elements. The extruder may also be referred to as a plasticizing unit or injection unit. This plasticizing or injection unit may in particular comprise a screw conveyor. The screw conveyor is an extruder screw, which is mounted adjustably within the screw cylinder in the axial direction and that is linearly movable back and forth, that is movably mounted in the conveying direction and counter to the conveying direction. The auger may be controlled such that it is operated during the introduction and conveying of the polymeric precursor from the feed zone to the mixing zone or to the exit zone only with a relatively low back pressure, so that the auger within the screw cylinder in the axial direction against the conveying direction becomes. As a result of such pushing back of the screw conveyor, an enlarged screw antechamber is formed at the front end of the screw conveyor or in the region of an outlet zone downstream of a backflow blocking device, in which the plastified and mixed polymeric precursor is kept at a controlled temperature before being introduced under elevated pressure into a cavity Injection mold is pressed. In order to carry out the pressing, the auger is pushed forward from its rear position with increased pressure in the conveying direction, so that the screw antechamber is reduced in size and the polymeric precursor is forced into the cavity of the injection mold. This closes the Rückströmsperr- Device, so that no polymeric precursor from the screw antechamber is pushed back into the mixing zone. Finally, the auger can be kept under a reprint, so that during a cooling process in the cavity of the injection mold from a remaining residual mass cushion optionally a supplementary mass of polymeric precursor can be pushed into the cavity to compensate for the volume shrinkage.

By plasticizing the polymeric precursor in the extruder or in the plasticizing unit and by adding activating individual components, such as the activators and / or catalysts, via at least one injection nozzle provided on the extruder, according to the invention mixing takes place, optionally an initial activation of the polymer Pre-product in the metering of the extruder, but according to the invention, the essential activation or polymerization takes place only in the cavity of the injection mold by heating the polymeric reaction resin mixture at least substantially or completely takes place only in the cavity of the injection mold on the reaction temperature of the polymeric reaction resin mixture.

The activating individual components, such as the activators and / or catalysts, can be metered into the polymer precursor in the extruder, in particular in the liquid or powdery state or in an at least partially plasticized or fully plasticized state. Such metered addition may be effected by means of a metering pump, which introduces the activator and / or the optional catalyst from a respective reservoir into an injection zone of the extruder. The dosing pump must be able to build up a pressure which is greater than the back pressure of the polymeric precursor in the extruder, i. in the injection zone of the extruder.

The position of the injection nozzle should be at a point at which a still sufficiently good mixing of the activating individual component, such as the activator and the optional catalyst with the polymeric precursor by a mixing action of rotating within the screw cylinder extruder screw. can take place. In a downstream in the conveying direction of the extruder screw of the injection zone mixing zone of the extruder screw mixing elements may be arranged with which a homogeneous mixing of the two- or multi-phase system (polymeric precursor, activators and / or catalysts) can take place. Due to the conveying effect of the extruder screw, the two-phase or multiphase system, ie the polymeric reaction resin mixture in the extruder, is conveyed further forward to an exit zone of the extruder. By means of a non-return device in the region of the outlet zone of the extruder, it is also possible in particular to reproduce low-viscosity materials in a reproducible manner, ie in a controlled manner with regard to the delivery rate. The plasticizing unit can be designed accordingly that even materials with low viscosity can be dosed. The extruder screw may have corresponding shearing and / or mixing elements in order to be able to produce a homogeneous mixing of the polymer precursor with the activating individual components, such as the activator and the optional catalyst.

By an inclination of the dosing unit, i. the extruder may be followed by a re-flow of the liquid starting components, i. the polymeric reaction resin mixture can be ensured in a special way. An inclination is understood to mean that a feed zone of the extruder is arranged higher with respect to the direction of gravity than the exit zone of the extruder or as the nozzle of the extruder.

The conveying device, which is referred to below as a dosing unit, comprises, inter alia, the extruder and in each case at least one storage container, a metering pump and an injection nozzle. The metering unit may comprise a screw cylinder, in which a conveyor, ie an extruder screw, is located. The conveyor may be capable of conveying both solids and liquids. In a front region of the dosing unit, ie in the outlet zone of the extruder, a spray nozzle is arranged, which is designed to be able to close the outlet of the dosing unit, ie the extruder. For example, the extruder may have a non-return device. On the dosing unit or on the extruder, a feeding device is arranged. The feeder may comprise a tank in which the polymeric precursor is stored. In the area of the injection zone, the extruder has the at least one injection nozzle. The at least one activating substance, such as the activator and / or the optional catalyst, in particular in liquid form, is metered in via the injection nozzle. The metering pump is designed to be able to build up a necessary minimum pressure in order to be able to inject the activating substance, in particular the activator and / or the optional catalyst, into the injection zone of the extruder counter to the back pressure of the polymeric precursor. The dosing pump can in particular be mounted on the dosing unit, ie on the extruder.

The conveyor, i. The extruder screw can be subdivided into several sections or areas. In a first section of a feed zone, the polymeric precursor can be conveyed from the feeder into the feed and mixing space of the extruder and from there into the injection zone. In a mixing zone following in the conveying direction to the injection zone, mixing and / or shearing elements, in particular on the conveyor, i. on the extruder screw to be able to mix the polymeric precursor with the injected via the injection nozzle activating substances, such as the at least one activator and / or the at least one optional catalyst. Accordingly, a very homogeneous mixture of polymeric precursor and the activating agents, such as the at least one activator and / or the at least one optional catalyst, can be produced to obtain the polymeric reaction resin mixture.

In accordance with the invention, a temperature control of the polymeric reaction resin mixture is carried out at a temperature below its reaction temperature, and a conveying out of this polymeric reaction resin mixture from an outlet zone of the extruder downstream of the extruder screw into the mixing zone is carried out into the cavity of the injection mold, and only in the cavity of FIG Injection mold heating of the polymeric reaction resin mixture the reaction temperature of the polymeric reaction resin mixture is carried out, an improved plastic injection molded part can be produced. Thus, for example, at least predominantly avoided or even completely prevented that the polymeric reaction resin mixture already reacted or hardened within the extruder. By heating the polymeric reaction resin mixture to the reaction temperature of the polymeric reaction resin mixture only in the cavity of the injection mold, the reaction process or hardening or curing of the polymeric reaction resin mixture can be controlled by controlling the temperature over time within the injection mold or within the cavity , In addition, it can be avoided or even completely prevented that a residue of polymeric reaction resin mixture undesirably cures within the extruder. A previously required flushing of the extruder may accordingly be omitted under certain circumstances.

As already mentioned, a backflow blocking device can be located in the outlet zone of the extruder. The non-return device may comprise, for example, a non-return valve known to those skilled in the art. Due to the conveying effect of the screw conveyor, the activated material, ie the polymeric reaction resin mixture, is conveyed beyond the backflow blocking device to the outside of the extruder and conveyed into the injection mold. The polymeric reaction resin mixture can either be conveyed directly into the cavity of the injection mold or conveyed into an antechamber of the injection mold, from which the polymeric reaction resin mixture in a precisely predetermined amount, which may be predetermined by a Dosierhub the vestibule, in the cavity of the injection mold is further promoted. If the antechamber or the metering stroke of the antechamber is completely filled with the precisely predetermined amount of polymeric reaction resin mixture, the Rückströmsperrvorrichtung or the spray nozzle of the extruder can be closed and the conveyor or the extruder decoupled from the injection mold, in particular weggefahren. In this case, the rotary motion of the conveyor rack in the extruder can be stopped. By uncoupling the extruder from the injection mold can be prevented, inter alia, that the polymer reaction resin mixture in the extruder is heated above its reaction temperature due to heat conduction from the injection mold to the extruder.

By injecting the at least one activator and the at least one optional catalyst from outside the extruder into the injection zone of the extruder screw in which the polymeric precursor is present, and then mixing the polymeric precursor with the injected at least one activator and with the injected at least one an optional catalyst to a polymeric reaction resin mixture in a downstream in the conveying direction of the extruder screw of the injection zone mixing zone of the extruder screw and while the reaction resin mixture is maintained at a temperature below their reaction temperature, polymeric reaction resin mixture can be prepared in which the individual components (polymeric precursor, activators, Catalysts) can be metered separately even in very different amounts, ie in very different proportions and still a very homogeneous polymeric R tion resin mixture can be produced. For example, aging of the substances or of the substance mixture on the processing plant, ie in particular within the extruder, may be prevented or at least significantly delayed, for example. In addition, during an ongoing production of plastic injection molded parts adjustments to the recipe, in particular with regard to the mixing ratio of polymeric precursor, activators and optional catalysts, can be made in a simple manner. This may possibly be done in particular without the production process having to be interrupted. In addition, for example, in a combination process, the spray system can be very compact removed. For example, in a Z-position, ie in an oblique arrangement of the extruder, a thermoplastic material can be processed on a main unit and a reactive component can be processed on the Z-unit. In the case of a planned production stop, the metering, for example, of the activator can be turned off, ie the metering pump can be stopped, and the extruder can very quickly with the (alone unreactive) po- lymeren precursor be rinsed. Any already activated material is then present only in small quantities and can be discharged from the extruder in a simple manner, without having to circulate it.

The temperature control of the reaction resin mixture in the mixing zone of the extruder screw and / or in the outlet zone of the extruder can be carried out at a temperature between 20 degrees Celsius and 60 degrees Celsius.

The heating of the polymeric reaction resin mixture in the cavity of the injection mold can be carried out at a temperature between 50 degrees Celsius and 150 degrees Celsius.

The at least one activator and the at least one optional catalyst can be injected in the liquid state in the injection zone of the extruder screw.

Cooling of the cured plastic injection-molded part in the cavity can take place after the plastic injection-molded part has been heated and hardened before the plastic injection-molded part is ejected from the injection-molded part.

The cooling of the cured plastic injection molded part can be at a temperature between 60 degrees Celsius and 80 degrees Celsius, before the plastic injection molded part is ejected from the injection mold.

In the following, some examples of temperature guides according to the invention in the plasticizing, ie in the extruder and in the injection mold are briefly explained. The storage container for the activator or the optional catalyst may be tempered and the plasticizing unit, ie the extruder screw of the extruder according to the invention and / or the screw cylinder of the extruder according to the invention may be tempered. The storage container and / or the plasticizing unit may have a temperature between 20 degrees Celsius and 60 degrees Celsius. The temperature- Guidance on these components can preferably be done by a water temperature. Alternatively or additionally, it is also possible to carry out an oil temperature control or an electrical temperature control. The choice of the temperature at the reservoir and at the plasticizing unit depends essentially on the viscosity of the component used. The viscosity should generally be between 150 and 5000 millipascal seconds (mPa.s). Increasing the temperature can reduce the viscosity of most components, resulting in an improved mixing effect in the system and lower injection pressures.

The temperature in the mold or in the mold, i. in the injection mold or on the cavity, however, should be chosen so that a sufficiently fast and complete reaction of the reactive component is achieved. The temperature on the tool surface should be between 50 and 150 ° C. For an improved demoulding, a variothermal temperature control can preferably also be adjustable on the tool surface. Thus, the reactivity at high temperatures (50-150 ° C) take place and then the temperature is lowered again for improved demolding (about 30-80 ° C).

The materials described in more detail below can be used, for example. Basically, an injection molding plant according to the invention can be used for the treatment of acrylic acid esters. For example, the component of freewheels is, for example, primarily a mixture of urethane acrylate and isobornyl acrylate, and also cobalt bis (2-ethylhexanoate). Alternatively, it may be 1,6-hexanediol diacrylate as the basic component, i. act as a polymeric precursor and to 1, 1, 1 -Trihydroxymethylpropyltriacrylat as cross-linker. For the activator, bis (4-tert-butylcyclohexyl) peroxydicarbonate can be used, this being a powdery product. Other products of activators may be peroxides.

In all variants of the method, the polymeric reaction resin mixture can optionally be sprayed onto a previously sprayed, thermoplastic or thermoset component. In such spraying, the polymeric reaction resin mixture with the previously sprayed, thermoplastic or thermoset component form a solid connection. For example, the polymeric reaction resin mixture thereby form a cover layer or serve as an impregnating material, which can be applied, for example, to a textile material located in the cavity as a component.

In general, in all variants of the method and also in all variants of the injection molding machine, the polymeric reaction resin mixture can either be injected into a single cavity or the polymeric reaction resin mixture can be injected into two or more cavities, in particular simultaneously. The injection mold may optionally have a single cavity or have multiple cavities.

The object of the invention is also achieved by an injection molding machine comprising an injection mold comprising at least one cavity and comprising an extruder with a screw cylinder and an extruder screw rotating in the screw cylinder, wherein between the screw cylinder and the extruder screw a feed zone, an injection zone, a mixing zone and an exit zone is formed, and comprising a machine controller, wherein the machine controller is adapted to control the injection molding machine according to a method according to one or more of the described embodiments, and the injection molding machine, a reservoir containing the at least one activator or the at least one optional catalyst, and a metering pump and the extruder has an injection nozzle connected to the injection zone, wherein the metering pump is formed, the activator contained in the reservoir or optional Katal Ysator out of the reservoir out and inject via the injection nozzle in the injection zone.

The injection molding machine according to the invention can form a processing machine for reactive plastics and to this extent comprise a conventional injection molding machine, ie those known to those skilled in the art. The injection molding machine can be a multi-component injection molding machine. A dosing unit according to the invention, ie, the conveyor according to the invention, which includes, inter alia, the extruder and each at least one reservoir, a metering pump and an injection nozzle can be mounted as an auxiliary unit, in particular in a Z-position on an existing injection molding. Injection of reactive components can be carried out through a fixed platen. Such an embodiment is explained in more detail in the description of the figures. Other variants may be juxtaposed, vertically, horizontally in the L-position or arranged opposite auxiliary units.

The extruder may have a tempering device, which is thermally coupled to the screw cylinder, in particular a temperature-controlled or oil-tempered tempering device, which is designed to keep the polymeric reaction resin mixture in the extruder between the screw cylinder and the extruder screw below a reaction temperature of the polymeric reaction resin mixture.

The tempering device may be configured to adjust the reaction resin mixture in the mixing zone of the extruder screw and / or in the outlet zone of the extruder to a temperature between 20 degrees Celsius and 60 degrees Celsius.

The injection mold may have a thermally coupled to the cavity heater, which is adapted to heat the polymeric reaction resin mixture in the cavity of the injection mold to the reaction temperature of the polymeric reaction resin mixture.

The heating device may be configured to heat the polymeric reaction resin mixture in the cavity of the injection mold to a temperature between 50 degrees Celsius and 150 degrees Celsius.

The injection mold may have a thermally coupled to the cavity cooling device which is adapted to cool the obtained after heating and curing of the polymeric reaction resin mixture cured plastic injection molded part before ejecting the plastic injection molded part from the injection mold in the cavity. The cooling device may be configured to recool the cured plastic injection molded part to a temperature between 60 degrees Celsius and 80 degrees Celsius before ejecting the plastic injection molded part from the injection mold.

The extruder can have a backflow blocking device associated with the discharge screw in the conveying direction of the extruder screw. The non-return device may comprise, for example, a non-return valve known to those skilled in the art. The conveying action of the screw conveyor activates the activated material, i. the polymeric reaction resin mixture through the Rückströmsperrvorrichtung across funded outside the extruder and conveyed into the injection mold inside. The closing mechanism of the non-return device can be either actively controlled, e.g. by means of a spring, or passively actuated by the injection movement.

The injection molding machine may include a sprue bush provided with a thermal isolator configured to limit heat conduction between the extruder and the injection mold when a nozzle of the extruder is coupled to the sprue bush.

The sprue bushing of the reactive component can be designed so that the best possible separation of the hot and cold systems takes place. For example, plastic insulating members (e.g., PEEK or PTFE) or so-called "barrier cooling" may be used, which should be contoured.

An exemplary embodiment of the invention is explained in more detail in the following description of the figures with reference to the accompanying schematic figures. Concrete features of this embodiment, irrespective of the specific context in which they are mentioned, if appropriate also considered individually or in other combinations, represent general features of the invention.

Show it: 1 is a schematic representation of an exemplary embodiment of an injection molding machine according to the invention, which is designed to carry out a method according to one or more of the embodiments described, and

2 shows a schematic representation of an exemplary embodiment of a feed zone, injection zone, mixing zone and exit zone of an extruder of the injection molding machine formed between a screw cylinder and an extruder screw.

The injection molding machine 1 shown in FIG. 1 has a machine frame 2 on which a first extruder 3 and an injection mold 4 are arranged. The injection mold 4 comprises a fixed platen 5 with a stationary injection mold half 4a and a movable platen 6 with a movable injection mold half 4b. The movable platen 6 and the movable Spritzgießformhälfte 4b are mounted adjustable along the spars 7 relative to the fixed platen 5 and relative to the stationary Spritzgießformhälfte 4a in a conventional manner. Between the fixed injection mold half 4a and the movable injection mold half 4b, a cavity 8 is formed, in which plastic injection parts can be formed. The injection molding machine 1 of the embodiment shown is designed for the production of multi-component components and, in addition to the first extruder 3, comprises a second extruder 9, which charges the cavity 8 with a reaction resin mixture. The injection molding machine 1 of the embodiment shown may be a turntable machine. The second extruder 9 is provided in order to be able to carry out a method according to the invention according to one or more of the embodiments described.

The second extruder 9 comprises a screw cylinder 10 and an extruder screw 1 1 rotating in the screw cylinder 10. The extruder screw 1 1 is rotatably driven by an electric drive 12, of a machine control 13 of the Injection molding machine 1 is controlled. Via a feed device 14, a polymer precursor is introduced into the second extruder 9 in the region of a feed zone 15 into a conveying and mixing chamber 16 of the second extruder 9 formed between the screw cylinder 10 and the extruder screw 11. The second extruder 9 also has an injection nozzle 22 which is designed to inject an activator and an optional catalyst in the region of an injection zone 17 into the conveying and mixing space 16 of the second extruder 9 formed between the screw cylinder 10 and the extruder screw 11.

Accordingly, the second extruder 9, as shown in more detail in Fig. 2, a feed zone 15, an injection zone 17, a mixing zone 18 and an exit zone 19. The activator A or the optional catalyst K can, as indicated by the arrows in FIG. 2, be injected into the injection zone 17. The polymeric precursor V is charged in the feed zone 15.

The activator or the optional catalyst can each be located separately in a reservoir 20, wherein in FIG. 1 for the sake of simplicity, only a single reservoir 20 is shown. Accordingly, in each case a separate storage container 20 can be provided for the activator or the optional catalyst. In each case, a metering pump 21 conveys, for example, the activator located in the reservoir 20 out of the reservoir 20 and into the injection zone 17 of the second extruder 9 via the injection nozzle 22. The metering pump 21 can be controlled, for example by means of the machine control 13, in particular with regard to delivery time, delivery pressure and / or delivery speed and therefore with regard to the delivery rate, in particular regulated.

The machine controller 13 is designed to control the injection molding machine 1 according to a method according to one or more of the described embodiments.

The injection molding machine 1 thus has a reservoir 20 containing the at least one activator or the at least one optional catalyst, as well as a metering pump 21, wherein the second extruder 9 has an injection nozzle 22 connected to the injection zone, and the metering pump 21 is designed to deliver the activator or optional catalyst contained in the reservoir 20 out of the reservoir 20 and via the injection nozzle 21 into the injection zone 17 to inject.

The second extruder 9 has in the case of the present embodiment, a thermally coupled to the screw cylinder 10 tempering device 23, which may be in particular a water tempered or oil tempering temperature control 23, which is formed in the second extruder 9 between the screw cylinder 10 and the extruder screw 1 to keep the polymeric reaction resin mixture below a reaction temperature of the polymeric reaction resin mixture.

As schematically indicated in FIG. 1, in the case of the present exemplary embodiment, the injection mold 4 has a heating device 24 thermally coupled to the cavity 8 and designed to heat the polymeric reaction resin mixture in the cavity 8 of the injection mold 4 to the reaction temperature of the polymeric reaction resin mixture ,

In addition, in the case of the present embodiment, the injection mold 4 has a thermally coupled to the cavity 8 cooling device 25, which is formed after heating and curing of the polymeric reaction resin mixture obtained cured plastic injection molded part before ejecting the plastic injection molded part from the injection mold 4 in the cavity 8 to cool.

In the case of the present embodiment, the machine control 13 is designed or set up, the inventive method for producing plastic injection molded parts in a cavity 8 of an injection mold 4 from a injected into the cavity 8 by means of an extruder 9 polymeric reaction resin mixture, a polymeric precursor, at least one activator and at least one optional catalyst to perform on the injection molding machine 1. The method controlled by the machine controller 13 accordingly comprises the steps of introducing the polymeric precursor into a feed zone 15 of the extruder screw 1 1 of the extruder 9; conveying the polymeric precursor from the feed zone 15 into an injection zone 17 of the extruder screw 1 1 downstream of the feed zone 15 in the conveying direction of the extruder screw 11, injecting the at least one activator and the at least one optional catalyst from outside the extruder 9 into the injection zone 17 Extruder screw 1 1, in which the polymeric precursor is present, the mixing of the polymeric precursor with the injected at least one activator and with the injected at least one optional catalyst to a polymeric reaction mixture in a downstream in the conveying direction of the extruder screw 1 1 of the injection zone 17 mixing zone 18 of Extruder screw 1 1 and tempering the reaction resin mixture at a temperature below their reaction temperature, the feeding out of the polymeric reaction resin mixture from a downstream in the conveying direction of the extruder screw 1 1 of the mixing zone 18 Off passage zone 19 of the extruder 9 in the cavity 8 of the injection mold 4 in, as well as the heating of the polymeric reaction resin mixture in the cavity 8 of the injection mold 4 to the reaction temperature of the polymeric reaction resin mixture.

In a first embodiment, the temperature control of the reaction resin mixture takes place in the mixing zone 18 of the extruder screw 1 1 and / or in the outlet zone 19 of the extruder at a temperature between 20 degrees Celsius and 60 degrees Celsius.

In an alternative embodiment or variant complementary to the second embodiment, the heating of the polymeric reaction resin mixture takes place in the cavity 8 of the injection mold 4 at a temperature between 50 degrees Celsius and 150 degrees Celsius.

In all variants, the at least one activator and the at least one optional catalyst in liquid state can be injected into the injection zone 17 of the extruder screw 1 1. Cooling of the cured plastic injection-molded part in the cavity 8 after heating and curing of the polymeric reaction-resin mixture to the plastic injection-molded part, prior to ejection of the plastic injection molded part from the injection mold 4. The cooling of the cured plastic injection-molded part can be carried out in particular to a temperature between 60 degrees Celsius and 80 degrees Celsius before the plastic injection molded part is ejected from the injection mold 4.

Injection molding machine

machine frame

first extruder

injection mold

a fixed Spritzgießformhälfteb movable injection mold half

fixed platen movable platen spars

cavity

second extruder

0 screw cylinder

1 extruder screw

2 electric drive

3 machine control

4 feed device

5 feed zone

6 conveying and mixing room

7 injection zone

8 mixing zone

9 exit zone

0 storage tank

1 dosing pump

2 injection nozzle

3 tempering device

4 heating device

5 cooling device

6 non-return device

7 sprue bush

8 insulation device

9 spray nozzle

Claims

Claims The invention relates to a method for producing plastic injection-molded parts in at least one cavity

(8) an injection mold (4) from one into the cavity (8) by means of an extruder

(9) an injected polymeric reaction resin mixture comprising a polymeric precursor, at least one activator and at least one optional catalyst, comprising the steps of:

Introducing the polymeric precursor into a feed zone (15) of a

Extruder screw (1 1) of the extruder (9),

Conveying the polymer precursor from the feed zone (15) into an injection zone (17) of the extruder screw (11) downstream of the injection zone (15) in the conveying direction of the extruder screw (11);

Injecting the at least one activator and the at least one optional catalyst from outside the extruder (9) into the injection zone (17) of the extruder screw (11) in which the polymeric precursor is present,

Mixing the polymeric precursor with the injected at least one activator and with the injected at least one optional catalyst to form a polymeric reaction resin mixture in a downstream in the conveying direction of the extruder screw (1 1) of the injection zone (17) mixing zone (18) of the extruder screw (1 1) and Tempering the polymeric reaction resin mixture at a temperature below its reaction temperature,

- Carrying out the polymeric reaction resin mixture from a downstream in the conveying direction of the extruder screw (1 1) of the mixing zone (18) outlet zone (19) of the extruder (9) into the injection mold (4)

Heating the polymeric reaction resin mixture in the cavity (8) of the

Injection mold (4) to the reaction temperature of the polymeric reaction resin mixture.

Method according to claim 1,

characterized in that the tempering of the reaction resin mixture in the mixing zone (18) of the extruder screw (1 1) and / or in the outlet zone (19) of the extruder (9) at a temperature between 20 degrees Celsius and 60 degrees Celsius.

Method according to claim 1 or 2,

characterized in that the heating of the polymeric reaction resin mixture in the cavity (8) of the injection mold (4) takes place at a temperature between 50 degrees Celsius and 150 degrees Celsius.

Method according to one of claims 1 to 3,

characterized in that the at least one activator and the at least one optional catalyst in liquid state of aggregation in the injection zone (17) of the extruder screw (1 1) is injected.

Method according to one of claims 1 to 4,

characterized by cooling the cured plastic injection molded part in the cavity (8) after heating and curing the polymeric reaction resin mixture to the plastic injection molded part, before ejecting the Kunststoffspntzteils from the injection mold (4).

Method according to claim 5,

characterized in that the cooling of the cured Kunststoffentztsteils to a temperature between 60 degrees Celsius and 80 degrees Celsius, before the plastic injection molded part from the injection mold (4) is ejected.

7. The method according to any one of claims 1 to 6,

characterized in that the polymeric reaction resin mixture is sprayed onto a previously sprayed, thermoplastic or thermoset component.

8. Injection molding machine, comprising an injection mold (4), the at least one cavity (8) and comprising an extruder (9) with a screw cylinder (10) and a screw cylinder (10) rotating extruder screw (1 1), wherein between the screw cylinder (10) and the extruder screw (1 1) a feed zone (15), an injection zone (17), a mixing zone (18) and an outlet zone (19) is formed, and comprising a machine control (13), characterized in that the machine control (13) is adapted to control the injection molding machine (1) according to a method according to one of claims 1 to 7, and the injection molding machine (1) containing a at least one activator or at least one optional catalyst reservoir (20), and a metering pump ( 21) and the extruder (9) has a to the injection zone (17) connected to the injection nozzle (22), wherein the metering pump (21) is formed, in the Vorra tsbehälter (20) contained activator or optional catalyst from the reservoir (20) out and inject via the injection nozzle (22) in the injection zone (17).

9. Injection molding machine according to claim 8,

characterized in that the extruder (9) has a thermally coupled to the screw cylinder (10) tempering device (23), in particular a water tempered or oil tempered temperature control device (23) which is formed in the extruder (9) between the screw cylinder (10). and the extruder screw (1 1) located to contain polymeric reaction resin mixture below a reaction temperature of the polymeric reaction resin mixture.

10. Injection molding machine according to claim 8 or 9,

characterized in that the Spritzgießfornn (4) has a thermally coupled to the cavity (8) heating device (24) which is formed, the polymeric reaction resin mixture in the cavity (8) of the injection mold (4) to the reaction temperature of the polymeric reaction resin mixture to heat.

1 1. Injection molding machine according to one of claims 8 to 10,

characterized in that the injection mold (4) has a thermally coupled to the cavity (8) cooling device (25), which is formed, the obtained after heating and curing of the polymeric reaction resin mixture cured plastic injection molded part before ejecting the plastic material part the injection mold (4) in the cavity (8) to cool.

12. Injection molding machine according to one of claims 8 to 1 1,

characterized in that the extruder (9) has a in the conveying direction of the extruder screw (1 1) of the outlet zone (19) associated Rückströmsperrvor- direction (26).

13. Injection molding machine according to one of claims 8 to 12,

characterized in that the injection molding machine (1) has a sprue bush (27) which is provided with a thermal insulation device (28) which is designed to limit heat conduction between the extruder (9) and the injection mold (4) if a spray nozzle ( 29) of the extruder (9) is coupled to the sprue bushing (27).