DE202008007304U1 - Device for processing plastics - Google Patents

Abstract

Apparatus for processing plastics, in particular thermosetting polyurethane, wherein at least two components causing a crosslinking or reaction are mixed together, with a processing unit comprising a cylinder in which a screw is rotatably received, the cylinder having at least one filling opening and one outlet opening, and with a mold containing a cavity for receiving and curing the mixed components, characterized
In that the processing unit is designed as an injection molding unit (1) with a spray nozzle (8), through which the plasticized injection molding compound consisting of the first component (5) and the second component (7) into the cavity (9) of the molding tool (10). is injected
- that the cylinder (2) of the injection molding unit (1) has at least one second filling opening (6) for feeding the second component (7),
- That the screw (3) of the cylinder (2) via a mechanical coupling unit (24) with a metering unit (11, 36) is connected, such that in dependence on an axial position of the ...

Description

The Invention relates to a device for processing plastics, in particular thermosetting polyurethane, wherein at least two a Crosslinking or reaction causing components mixed together with a processing unit containing a cylinder, in which a worm is rotatably received, wherein the cylinder at least one filling opening and one outlet opening and with a mold containing a cavity for receiving and curing the mixed components, characterized.

From the DE 10 2006 038 197 A1 There is already known a device for processing thermosets, which comprises a processing unit with a cylinder and in a worm arranged in this cylinder. The cylinder comprises a feed opening for supplying a first component and a second component, which are mixed in the cylinder by means of the screw. In order for the processing unit to be operated continuously, an injection line leading away from an outlet opening of the processing unit is assigned a memory unit in which the intermediate material in the processing unit is temporarily stored. Further, the injection line is associated with an injection device with an injection piston, so that the mixed material can be injected at a relatively high pressure in the mold. Other materials, such as fillers or additives, can be supplied via further downstream of the filling opening arranged further filling openings. A disadvantage of the known device is that the component cost for a continuous operation of the processing unit is relatively expensive. For this purpose, at least the storage unit is required. A further disadvantage is that the supply of the components from corresponding storage containers to the processing unit must always be re-metered with changing processing units.

task The present invention is therefore an apparatus for processing of plastics in such a way that the processing effort, in particular the dosage is reduced.

to Solution of this problem is the inventive Device in conjunction with the preamble of the protection claim 1, characterized in that the processing unit as an injection molding unit is formed with a spray nozzle through which the plasticized Injection molding composition consisting of the first component and the second component in the cavity of the mold is injected, that the cylinder of the injection molding at least a second filling opening for feeding the second component that the screw of the cylinder over a mechanical coupling unit connected to a metering unit is such that, depending on an axial position the worm through the second filling opening introduced amount of the second component is metered.

One Advantage of the device according to the invention exists in that an injection molding unit for mixing at least two components on the one hand and for injection under pressure of the mixed components into a mold on the other hand useable is. The component cost is thereby relatively low. Another Advantage of the device according to the invention results itself from the fact that a dosing unit for the supply the second component via a mechanical coupling unit with a worm of the processing unit is coupled. To this Way, the dosage of the second component depending take place from the axial position of the screw. This can advantageously a defined supply of the second component in dependence from the volume intended for the injection molding unit the first component or a stroke of the screw or an axial Speed of the screw done. It is thus a continuous Supply of the second component in dependence from the speed or speed of the worm. Related to the Schneckenweg can thus be a constant amount the second component into a cylinder of the processing unit introduce what a thorough and complete mixing the components in the cylinder favors. Advantageous can the injection molding of the invention Device as a conventional injection molding unit used when the second filler opening is sealed by means of a plug.

According to a preferred embodiment of the invention, the screw is connected or coupled via the mechanical coupling unit with the metering unit such that, depending on a forward stroke and / or a return stroke of the screw, a predetermined percentage volume or amount of the second components based on the first component a second filling opening of the cylinder is supplied. The longer the stroke of the screw, the larger the volume of the second component, which is supplied through the second filling opening. For the same forward stroke and return stroke of the screw, the same volume fraction of the second component is fed into the second filler opening at each cycle of the screw. If, for example, the advance stroke or return stroke of the screw is greater due to another configuration of the processing unit, so that the volume of the first component supplied via the first filling opening is greater, it is also indicated Tels the stroke-dependent dosing unit according to the invention without changing the setting a corresponding percentage volume fraction of the second component via the second filling opening in the cylinder of the processing unit. The conversion effort is thus comparatively low.

To a development of the invention is a piston rod of the dosing over the mechanical coupling unit rigid with the screw of the injection molding unit connected. This advantageously makes a low-maintenance mechanical Coupling between the screw on the one hand and the dosing unit guaranteed on the other hand.

To In a first variant of the invention, the dosing unit has a Double-acting dosing cylinder with double-sided piston rod (synchronous cylinder) on the one hand and a valve unit on the other hand, wherein the double acting cylinder two ports for the feeder the second component from a reservoir and two Connections for the supply of the second Component to the second filling opening of the injection molding unit. Advantageously, in a forward stroke and a return stroke of the Screw the same amount of volume into the second filling opening be pressed. While the second component, which is preferably formed as a liquid, from a Pressure chamber of the double-acting cylinder in the second filling opening is pressed, a suction chamber of the cylinder with another volume of the second component from the reservoir filled. There is thus a continuous supply and Mixing of the first component and the second component in the injection molding unit.

To In a further development of the invention, the valve unit has four 2/2-way valves on, each associated with the terminals of the Gleichgangszylinders are. The 2/2-way valves are controlled by a control unit controlled that the storage chamber associated connections on the one hand and the second filling opening assigned On the other hand, connections of the synchronous cylinder on the other hand alternately be opened or closed. Act in this way which are arranged on both sides of the piston of the Gleichgangzylinders Chambers alternately as suction and pressure chamber.

To In a further variant of the invention, the dosing unit can have a Have single-acting metering cylinder, wherein valves a Valve unit are controlled such that only at one Injection movement of the screw, ie at a forward stroke of the screw, the second component from the single chamber of the so formed Differential cylinder of the metering unit to the second filling opening is filled. The second filling opening is in the range of a static mixer, which in one Nozzle near the injection molding unit arranged is. It is a discontinuous feed or mixing of the first and second components in the injection unit.

To a development of the invention is the second component an additive, in particular from a prepolymer, formed a first component for forming a thermoset material is added in liquid form. Alternatively, the second Component formed from color additives or the like be.

embodiments The invention will be described in more detail below with reference to the drawings explained.

It demonstrate:

1 a block diagram of a device according to a first embodiment and

2 a block diagram according to a second embodiment of the invention.

A device according to the invention for processing plastics, in particular thermosetting plastics such as, for example, thermosetting polyurethane, has a first embodiment of the invention according to FIG 1 as the processing unit an injection molding unit 1 put on a cylinder 2 includes, in which a snail 3 is received rotatably. The cylinder 2 has a first filling opening 4 for supplying a first component 5 of the plastic material and a second filling opening 6 for supplying a second component 7 of the plastic material. The second filling opening 6 is in a range between an intake zone E and a compression zone K of the injection molding unit 1 arranged.

In a front end region of the injection molding unit 1 is designed as an outlet opening spray nozzle 8th arranged through which the components present as a mixture 5 and 7 during an injection process of the injection molding unit 1 with high pressure in a cavity 9 a mold 10 be injected and go there under pressure into the solid state. The cylinder shortened in the compression zone K 2 has in this area an example of heating shown 34 on, so that as granules or powder over the first filling opening 4 entered first component 5 is plasticized.

For the production or processing of thermosets, the second component 7 For example, be formed as a liquid prepolymer by means of a metering unit 11 dosed via the second filling opening 6 in the cylinder 2 is initiated to Mixing or mixing with the already existing first component 5 , Like from the 1 can be seen is the dosing unit 11 between the second filling opening 6 and one the second component 7 contained reservoir 12 arranged. The dosing unit 11 has a double-acting dosing cylinder 13 with a double-sided piston rod 14 acting as a dosing cylinder. The dosing cylinder 13 on the one hand has two the reservoir 12 associated ports A, B on the one hand and two of the second filling opening 6 assigned ports A ', B' on. The terminals A and A 'are at a first end 20 of the dosing cylinder 13 and the terminals B, B 'at a second opposite end 21 of the dosing cylinder 13 arranged.

Furthermore, the metering unit 11 a valve unit 15 with four way valves 16 . 17 . 18 . 19 on, which are preferably designed as 2/2-way valves. The directional valves 16 . 17 . 18 . 19 are each a port A, B, A ', B' of the metering cylinder 13 assigned. The directional valves 16 . 17 . 18 . 19 be through a common control unit 22 driven. The directional valves 16 . 17 . 18 . 19 are through appropriate lines 23 each with one of the ports A, B, A ', B' of the metering cylinder 13 on the one hand and with the reservoir 12 or the second filler opening 6 on the other hand.

The dosing unit 11 is via a mechanical coupling unit 24 stuck with the snail 3 the injection molding unit 1 connected. The mechanical coupling unit 24 For example, it may include one or more rods, with a first end of the mechanical coupling unit 24 rigid or solid with a back end 25 the snail 3 and another end of the mechanical coupling unit 24 with one end 26 the coupling rod 14 is rigidly connected. Optionally, the mechanical coupling unit 24 Also include a gear, so the way the piston rod 14 does not have to be the same with the way of the snail 3 ,

For dosing the second component 7 becomes the piston rod 14 depending on the movement of the screw 3 moved back and forth between a first end position and a second end position. One on the piston rod 14 attached piston 29 is periodically reciprocated along a stroke H1, wherein the stroke H1 is the same size as a forward stroke or return stroke H2 of the screw 3 , Optionally, by the in the mechanical coupling unit 24 integrated gears of the hub H1 also be longer or shorter than the stroke H2 of the screw 3 , This also allows the percentage volume ratio of the second components 7 to the first component 5 to be changed. Moves the snail 3 by a distance difference, the piston moves 29 parallel offset to the screw 3 in the same direction. As a result of the control of the valves 16 . 17 . 18 . 19 are in the on both sides of the piston 29 subsequent chambers 30 . 31 a volume fraction of the second component 7 , Depending on the direction of movement of the piston 29 is the one chamber 30 as a suction chamber and the other chamber 31 designed as a pressure chamber and vice versa. According to the in 1 shown state in which the screw 3 and the piston 29 in the direction of the arrow 32 be moved, forms in the direction of movement 32 in front of the piston 29 arranged chamber 31 the pressure chamber and in the direction of movement 32 of the piston 29 behind the same chamber 30 a suction chamber. The directional valves 16 . 17 . 18 . 19 are driven in such a way that by the movement of the piston 29 in the direction of the arrow 32 the second component 7 from the reservoir 12 through the pipe 23 in the suction chamber 30 sucked and the in the pressure chamber 31 share of the second component 7 through the pipe 23 is pressed into the second filling opening. For this purpose, there are the directional control valves 16 and 19 in one-way and the way valves 17 . 18 in a closed position.

In the opposite direction of movement of the piston 29 in the direction of the arrow 32 are the directional valves 16 . 19 in closed position and the directional control valves 17 . 18 in passing position. The chamber 30 then forms a pressure chamber, while the chamber 31 forms a suction chamber.

Due to the coupling of the piston rod 14 or of the piston 29 to the snail 3 thus become the chambers 30 . 31 alternating with a volume fraction of the second component 7 filled or deflated, leaving a targeted and by the way or speed of the screw 3 dependent dosage or supply of the second component 7 to the second filling opening 6 is guaranteed. This is a fixed percentage dosage of the second component 7 based on the first component 5 ensured while during the forward stroke of the screw 3 and the return stroke of the snail 3 in each case the same volume fraction of the second component 7 through the second filling opening 6 in the cylinder 2 is initiated.

By the reciprocation of the piston 29 depending on the stroke of the screw 3 becomes a continuous supply of the second component 7 on the one hand during the dosing cycle 'and on the other hand during the injection cycle' of the injection molding unit 1 guaranteed. That is, the flow rate of the supplied amount of the second component 7 per forward stroke and return stroke is constant.

According to a second embodiment of the device according to the invention 2 is unlike the previous embodiment for example, a dosing unit 36 provided by a single-acting metering cylinder (differential cylinder) 37 which is at a first end 38 a first connection 39 and a second connection 41 having. At one the first end 38 opposite second end 40 of the dosing cylinder 37 is a piston rod 14 of the dosing cylinder 37 via the mechanical coupling unit 24 with the snail 3 connected to the injection molding unit.

Same Components or component functions are denoted by the same reference numerals Mistake.

The dosing unit 36 has a valve unit 42 essentially consisting of a first valve 43 (Two-way valve) and a second valve 44 consists. The first valve 43 is the first connection 39 and the second valve 44 the second connection 41 assigned. By means of the control unit 22 become the valves 43 and 44 triggered such that in a spray cycle of the injection molding 1 that the first connection 39 with the reservoir 12 connecting first valve 43 in a closed position and that the second connection 41 with the second filling opening 6 the injection molding unit 1 connecting second valve 44 located in a passage position. The second filling opening 6 the injection molding unit 1 is located in a near-nozzle area of the same, in which a static mixer 45 is arranged. Thus, during the injection cycle, the second component becomes a chamber acting as a pressure chamber 46 of the dosing cylinder 37 in the injection molding unit 1 pressed or inoculated. In an opposite movement of the screw 3 That is, on a return stroke of the screw 3 as in 2 shown, the same, in which the injection molding unit 1 in a dosing cycle, the piston becomes 29 uniform with the snail 3 moved back, so that the volume of the chamber 46 increased and at a given position of the valves 43 . 44 , where the first valve 43 in passage position and the second valve 44 in the closed position, the second component 7 from the reservoir 12 in the chamber 46 is sucked. The chamber 46 This forms a suction chamber.

According to this embodiment, the injection molding unit 1 discontinuously filled with the second component, that is always during the injection cycle '.

The second component 7 For example, it may be formed as a prepolymer containing 10% by weight of the first component 5 , for example, an Elastollan material.

According to a further embodiment not shown, the injection molding unit may also have at least one further third filling opening. Between the third filling opening and a further reservoir could then another identical dosing 11 . 36 ,

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 102006038197 A1 [0002]

Claims (10)

Apparatus for processing plastics, in particular thermosetting polyurethane, wherein at least two components causing a crosslinking or reaction are mixed together, with a processing unit comprising a cylinder in which a screw is rotatably received, the cylinder having at least one filling opening and one outlet opening, and with a mold containing a cavity for receiving and curing the mixed components, characterized in that - the processing unit as an injection molding unit ( 1 ) is formed with a spray nozzle ( 8th ), through which the plasticized injection molding composition consisting of the first component ( 5 ) and the second component ( 7 ) into the cavity ( 9 ) of the molding tool ( 10 ) is injected, - that the cylinder ( 2 ) of the injection molding unit ( 1 ) at least one second filling opening ( 6 ) for supplying the second component ( 7 ), - that the snail ( 3 ) of the cylinder ( 2 ) via a mechanical coupling unit ( 24 ) with a dosing unit ( 11 . 36 ) is connected such that in dependence on an axial position of the screw ( 3 ) through the second filling opening ( 6 ) introduced amount of the second component ( 7 ) is metered. Apparatus according to claim 1, characterized in that the mechanical coupling unit ( 24 ) on the dosing unit ( 11 . 36 ) such that, depending on a forward stroke and / or a return stroke of the screw ( 3 ) a predetermined percentage volume of the second component ( 7 ) relative to the first component ( 5 ) of the second filling opening ( 6 ) is supplied. Device according to claim 1 or 2, characterized in that the dosing unit ( 11 . 36 ) via a piston rod ( 14 ) and a piston ( 29 ), wherein the piston rod ( 14 ) via the mechanical coupling unit ( 24 ) rigid and / or fixed to the screw ( 3 ) of the injection molding unit ( 1 ) connected is. Device according to one of claims 1 to 3, characterized in that the mechanical coupling unit ( 24 ) has a connecting linkage, which at a first end fixed to the screw ( 3 ) and at a second end fixed to the piston rod ( 14 ) of the dosing unit ( 11 . 36 ) connected is. Device according to one of claims 1 to 4, characterized in that the dosing unit ( 11 ) a double-acting metering cylinder ( 13 ) with a double-sided coupling rod on the one hand and a valve unit ( 15 ) on the other hand, over which the double-acting metering cylinder ( 13 ) with a storage container ( 12 ) of the second component ( 7 ) and with the second filling opening ( 6 ) of the injection molding unit ( 1 ) connected is. Device according to claim 5, characterized in that the valve unit ( 15 ) comprises four directional valves, so that two of the reservoir ( 12 ) associated connections (A, B) of the metering cylinder ( 13 ) and two of the second filling opening ( 6 ) associated connections (A ', B') of the metering cylinder ( 13 ) each via a directional control valve ( 16 . 17 . 18 . 19 ) with the reservoir ( 12 ) or the second filling opening ( 6 ) are coupled. Device according to one of claims 1 to 6, characterized in that the reservoir ( 12 ) and the second filling opening ( 6 ) associated connections (A, B, A ', B') of the metering cylinder ( 11 ) are respectively disposed at opposite ends thereof and that the directional control valves ( 16 . 17 . 18 . 19 ) of the dosing unit ( 11 ) are controlled such that by the means of the mechanical coupling unit ( 24 ) caused axial movement of the piston rod ( 14 ) towards a first end ( 20 ) of the metering cylinder ( 13 ) and / or toward a second end ( 21 ) of the metering cylinder ( 13 ) in a direction of movement in front of the piston ( 29 ) arranged chamber ( 31 ) second component ( 7 ) to the second filling opening ( 6 ) and a portion of the in the reservoir ( 12 ) second component ( 7 ) in the direction of movement behind the piston ( 29 ) arranged chamber ( 30 ) is sucked. Device according to one of claims 1 to 7, characterized in that the second filling opening ( 6 ) in a region between an intake zone (E) and a compression zone (K) of the injection molding unit ( 1 ) is arranged. Device according to one of claims 1 to 4, characterized in that the injection molding unit ( 1 ) a static mixer ( 45 ) in a region close to the nozzle, that the dosing unit ( 36 ) via the mechanical coupling unit ( 24 ) with the snail ( 3 ) connected single-acting metering cylinder ( 37 ) and that the dosing unit ( 36 ) a valve unit ( 42 ) with only two valves ( 43 . 44 ), so that during an injection movement of the screw ( 3 ) in the chamber ( 46 ) of the metering cylinder ( 37 ) portion of the second component ( 7 ) from the chamber ( 46 ) and to those in the area of the static mixer ( 45 ) arranged second filling opening ( 6 ) of the cylinder ( 2 ) is introduced into the same. Device according to one of claims 1 to 9, characterized in that the second component ( 7 ) an additive to the first component ( 5 ) and in a liquid state in the Vorratsbehäl ter ( 12 ).