DE1729134C3 - Process and devices for the production of long plastic foam hoses from multi-component plastics - Google Patents

Description

The invention relates to a method for producing long plastic foam tubes from multi-component plastics, in the one that projects between two endless forming belts Mandrel a moving release film is applied and in which the space between the release film and the outer molding tapes with a foamable multi-component plastic filled and the plastic is foamed and cured.

The invention also relates to an apparatus for carrying out this method.

The previously known German utility model 1855 548 is a casting machine for production Hoses of any length made from multi-component plastics have become known. With this machine is an endless, slotted rubber hose as an outer shape over two pulleys through a pipe out which this rubber tube is supposed to close to a closed outer shape. In this pipe in which the slotted rubber hose is moved, a mandrel extends in the center, which forms the inner shape to form for the plastic tube to be produced. Around this mandrel there is a roller tape-shaped release film, for example made of paper, wound This «release film should be placed on the mandrel Slipping along a separating agent between the filled liquid plastic mixture and the mandrel form. Instead of the slotted outer rubber hose, endless shaped belts or metal ones can also be used Link belts are provided. The production of hoses from plastic prepares on this machine considerable difficulties. Because it is a requirement for the production of flawless plastic foam hoses, that the inner shape moves at the same speed as the outer shape Otherwise cracks and perforations form in the hose. This basic requirement is known in this one Device not met The wrapping of the central

Domes with a foil tape will always encounter the difficulty that the wound foil tape settles on the dome and does not allow the hose to develop properly as far as a production of the hose at all

it is still possible

It is the object of the invention to provide a way to achieve in a simple manner that the Inner shape and the outer shape of the one to be produced

Hose move at the same speed, to produce flawless pipes and hoses.

The invention solves this problem in that a hose or a piece of hose is used as a separating film Run in polyethylene between the conveyor belts and during the filling and foaming of the Plastic the tube is filled with a pressure medium, then after the hardening of the plastic the The pressure medium is removed and the hose is pulled out.

The fact, known per se, is used here, that polyethylene cannot be glued. Polyethylene has such a high surface smoothness that none Adhesive and also no foaming multi-component plastic can stick firmly to this surface. By introducing such a hose between the two molding belts of the casting machine and the filling of this tube with a Pressure medium is achieved that the hose serving as the inner form made of polyethylene on the one hand does not can stick to a central mandrel, but on the other hand also not to the inner wall of the one to be produced Plastic foam hose can stick.

By introducing such a hose between the two molding belts of the casting machine as well as the filling of this hose with a pressure medium and its subsequent removal a pipe or a hose made of multi-component plastics can be produced in a simple manner.

The polyethylene hose is expediently made from the hardened multi-component plastic pipe or hose pulled out so that the polyethylene hose can be removed after the pressure medium has been removed with the help of a fixed at the beginning of the polyethylene tube and in this to the end pulls the running thread out of the hardened plastic foam tube. that the polyethylene hose is only torn off on a very short piece, because the tear-off process only takes place where the Hose start bent hose part is removed from the multi-component plastic, so only in the area of the bending point of the polyethylene hose. Of course, a very thin polyethylene tube is used here, if possible only as thick as a film.

The device for carrying out this manufacturing process is that of the in the room A mandrel extending into the interior between the two forming belts has at least one pressure release line has and on its part located outside of the two forming belts a supply of thin Polyethylene hose carries

The mandrel stiffens in the area where the plastic pressed in by the nozzle is still pasty, so has not yet received its strength, dsn middle area of the shape formed by the two forming belts, so that the hollow interior of the Multi-component plastic hose or 'pipe is thereby formed and fixed

At the same time, this centers the polyethylene hose and its position within the multi-component plastic Of course, a device is also provided which ensures that that of the part of the supply of polyethylene tubing located outside the two forming belts only so much hose is inserted into the casting machine between the two form belts that no wrinkles are formed in the polyethylene tube, but that the polyethylene tube tightly into the Casting machine is drawn into it. In this way, pieces of hose 10 and 20 m in length can be removed without produce further.

The mandrel reaching into the space between the two forming belts has a compressed air line, which blows out the polyethylene hose running into the forming belts with compressed air, so that the Polyethylene hose wrinkles the inside of the multi-component plastic hose that is being formed or pipe stiffening This compressed air may only be used - at least with thin polyethylene hoses from Film thickness - are under compressed air where the two forming belts are or where the one to be produced Multi-component plastic hose is already cured, the compressed air in one area is on act the polyethylene hose, in which the polyethylene hose can expand freely - that is

for example in the area in front of the two Ribbons - that is how the p, iyäthyienschlauch would burst under the pressure. That is why it is expedient that the mandrel arranged between the two forming belts in the area between the two

Forming bands carries one or more annular extensions and that between every two annular Extensions a separate pressure medium line is provided annular extension escaping to the rear

Media discharged

Understandably, one becomes the multi-component plastic mixed components, if possible, not in a completely liquid, low-viscosity state between the mold bands

!to water. Rather, one becomes a higher viscosity one, soon Choose a pasty state when you add the mixture between the molding belts to get the To solidify plastic. For this reason, the multicomponent plastic to be cast is used

through a somewhat longer tube in which the hardening process begins Pautious plastic also evenly in the cross-section to bring the polyethylene tube around, it is useful that the plastic foam

between the Fonnbänder conductive nozzle is formed ring-shaped

This is now a possibility of pipes and hoses of finite length, usually 10 to 20 m long. The length is limited by that Limited ability to store supplies of film-thick polyethylene tubing on the mandrel.

However, the invention now also creates the possibility of producing pipes and hoses of any length from Mehrkomponenf ^ n To manufacture plastics.

The procedure here is to put a piece of polyethylene tubing after the pressure medium has been removed pulls back a little inside the hose, then fills it again with a pressure medium and now with it again runs along with the resulting hose Here it is

μ useful when you have two pieces of tubing Polyethylene fills pulsating with pressure medium in push-pull and moves in push-pull In this way achieves that the pieces of tubing that form the inner shape are always only a short piece with the

! ends of the hose run along and then be withdrawn, then again after filling with a Print medium to serve as an inner shape. This possibility of manufacture takes advantage of the fact that the

gradually hardening foam of the plastic when the hardening process has already progressed, when the compressed air is removed from the hose piece, it does not immediately move away from the outer shape with its larger area, but only slightly inward under the pressure of foaming expands, but only so much that it is not burdened with a pressure medium and therefore expanded Hose section can retract perfectly to its starting position.

The device for carrying out the method in this embodiment is that the through the ring-shaped nozzle for the supply of the liquid multi-component plastic passing through The mandrel carries at least one piece of polyethylene tubing on its outside, to which a Pressure medium line from a pulsating pressure source inside the dome and which leads into Axial direction movably arranged and with a

is equipped with a drive which, if there is overpressure in the hose, approximates it uniformly with the forming belts emotional.

With this device, a hose can be produced in that the multi-component plastic is already in a rapidly solidifying and pasty form through the ring nozzle escapes and is constantly pressed into the tube shape through the polyethylene tube on the dome. There Polyethylene has such a smooth surface that it cannot be glued in the negative pressure phase following the pressure phase, tears away from the plastic foam and then by a piece can be withdrawn, after which it is re-inflated and stretched, spreading evenly moves with the movement of the forming belts. This creates a hose that you can choose Can give cross-sectional shapes that correspond to the shape of the dome and the hose.

This device can be improved in its mode of operation that on the dome one on his The end of a tube carrying a hose made of polyethylene can be displaced with an inner pressure medium line is arranged by a vibratory drive which moves the pipe in push-pull to the mandrel. Through this it is achieved that the piece of hose sitting on the mandrel is properly torn loose and withdrawn can be when the piece of tubing located on the pipe section against the plastic compound presses the molding strips and thereby holds them in place the hose located on the pipe. piece is torn loose, while the hose located on the mandrel is acted upon by the pressure medium

The essence of the present invention is based on an embodiment shown in the drawing explained in more detail It shows

F i g. 1 a schematic representation of the casting machine,

F i g. 2 shows, in an enlarged view, the mandrel reaching between the two forming belts,

F i g. 3 the beginning of the manufactured multi-component plastic hose,

F i g. 4 a schematic representation of the casting machine for the production of pipes of any length and Hoses,

F i g. 5 shows a section through the dome of FIG. 4 in the area of the molding strips.

The components of a multi-component plastic are stored in storage containers Ie and Xb and are conveyed by metering pumps 2a and Ib into a mixing chamber 3 in which a stirrer 4 is arranged. The multi-component plastic flows from the mixing chamber 3 through the line 5 between the two forming belts 7a and Tb, which are designed as endless belts and circulate around the deflecting rollers and drive rollers 6a, 6a ', 6b, 6b'. Between the

A mandrel 8, which has a compressed air line 9 in its interior, is sufficient to form strips 7a and Tb. This mandrel 8 has annular extensions 10a, 10 /> on its circumference, over which the Polyäthylenschlaucr 11 is led away. Compressed air flows through the compressed air line S into the polyethylene hose 11 in the part in front of the mandrel 8. This compressed air stiffens the polyethylene hose from the inside. A part of this compressed air escapes via the annular extension 10a and can from there in the area between the

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Line 12 arrive, which discharges escaping compressed air into the atmosphere. The mandrel 8 is held in a stand 13 which is attached to the machine frame. The mandrel 8 carries on its rear part a supply of polyethylene hose 11a, which is sufficient to produce 10 and 20 m long hose pieces in one operation. From Fig. 2 it can be seen how far the mandrel 8 rides into the forming belts 7a and 7i. Tensioners 14 ensure that only as much tube from the polyethylene tube supply 11a runs into the area between the two conveyor belts 7a and Tb as there is for a wrinkle-free movement of the polyethylene hose 1 i is required.
F i g. 3 shows that at the top part 11b, a thread 15 is fixed, with which the polyethylene tube of the produced multi-component tube can be pulled out. It is shown how this: Pulling out goes on. In the area of the deflection point 16 of the polyethylene hose 11, the polyethylene hose 11 detaches itself from the multi-component plastic hose 16. Understandably, the front piece 17 of the multi-component plastic must be cut off at the dividing line A. This piece of multi-component plastic is created!

at the beginning of the hose and is used to insert the polyethylene hose in the multi-component hose 16 must also be firmly enclosed at the beginning.

The manufacture of the multi-component plastics; in Fig. 4 takes place in the same way: In the storage container

so la and 1 b, the components are kept a multi-component plastic and are gefört'.rrt 2a and 2b in a mixing chamber 3, ir is disposed soft a stirrer 4 pumping by metering the multi-component synthetic flows out of the mixing chamber 3 material through the conduit 5 between the two forming belts 7a and 7b, which are designed as endless belts around the deflecting rollers and drive rollers 6a, 6a ', 66, 6b' . A figure in FIG. 1 extends between the shaping strips Ti and Tb. 4 but differently trained!

Dome 28, which has a compressed air line 29 in its interior and with which pipes and hoses of any length can be produced. This compressed air Line 29 leads under a hose section 210 made of polyethylene, which pulsates with a pressure medium is applied. This dome 28 is arranged so that it is in synchronization with the pulsating Print medium axiai swings back and forth This is dei Dome in the bearings of an oscillating drive 21i

arranged. This oscillating drive 212 consists of a pressure medium cylinder which is in synchronization oscillates with that pressure medium which acts on the hose section 210.

A tube 213 is arranged displaceably on the mandrel 28 and is driven by a further drive 214 is driven in the form of a pressure medium cylinder and thereby oscillates in push-pull to the mandrel. It goes without saying that you can also use this drive

other means known to those skilled in the art can be used. The tube 213 carries a hose section 215, which is made of polyethylene and by a pressure medium supplied through the pressure line 216 is applied pulsating. This pulsating pressure medium acts on the hose section 215 on the Tube 213 in push-pull to the pressure medium supplied by the pressure medium bypass 29 into the Hose section 210 on mandrel 28.

For this purpose 4 sheets of drawings

909 615/24

Claims (9)

Patent claims: 1. Method of making long plastic booms made of multi-component plastics, with the one on a load-bearing mandrel protruding between two endless shaped belts a moving release film is applied and in which the space between the release film and the outer molding tapes filled with a foamable multi-component plastic and the Plastic is foamed and cured, characterized in that as a separating film a hose or a piece of hose made of polyethylene run between the conveyor belts left and during the filling and foaming of the plastic the hose with a pressure medium filled, then after the hardening of the plastic, the print medium is removed and the Hose is pulled out. 2. The method according to claim 1, characterized in that that after removal of the pressure medium with the help of an am the polyethylene tube At the beginning of the polyethylene tube fastened and in this to the end of the thread pulls out of the hardened plastic foam tube 3. The method according to claim I _1, characterized in that a Schlsuchstfick made of polyethylene, after removing the pressure medium inside the hose withdraws a bit, then fills it again with a pressure medium and now can run with the resulting hose again 4. The method according to claim 3, characterized in that there are two pieces of tubing made of polyethylene pulsating with pressure in push-pull fills and moves in push-pull 5. Apparatus for the production of hoses of finite lengths from multicomponent plastics according to the method of claims 1 and 2 on a casting machine equipped with two endless forming belts and a mandrel projecting between them and carrying a band-shaped separating agent, characterized in that the in the space between the both forming belts (7a, 7b) extending mandrel (8) has a compressed air line (9) inside and carries a supply ( 11a) of thin polyethylene hose on its part outside of the two forming belts (Ja, 7b) 6. Apparatus according to claim 5, characterized in that the mandrel (8) in the area between the two forming belts (7a, 7b ) carries one or more annular extensions (10a, Wb) and that between two annular extensions (10a, XQb) one separate pressure medium line (12) is provided 7. Device for the continuous production of hoses of any length from multicomponent plastics according to the method of patent claims 1, 3 and 4, with a mandrel extending into the space between the two forming belts and with a nozzle for the supply of the liquid multicomponent plastic , characterized in that the mandrel (8) passing through the annular nozzle carries on its outside at least one hose piece (210) made of polyethylene, to which a pressure medium line (29) leads from a pulsating pressure source inside the dome (28) and which in Movable in the axial direction and equipped with an oscillating drive (212) which is synchronized with the pressure medium control and which moves the hose (210) approximately uniformly with the forming belts (7a, 7b) when there is pressure in the hose (210) 8. Apparatus according to claim 7, characterized in that on the mandrel (28) one at its end a tube (213) carrying a tube (215) made of polyethylene and having an inner pressure medium line (16) is arranged displaceably by an oscillating drive (214) which pushes the tube (213) moved to the mandrel (28) 9. Apparatus according to claim 7 and 8, characterized in that the plastic foam between the molding belts (7a, Tb) conductive nozzle is annular