DE1199485B - Method and device for the continuous production of hoses from two or more layers of different thermoplastics - Google Patents

Description

Method and device for the continuous production of hoses of two or more layers of different thermoplastics Die The invention relates to a method and an apparatus for continuous production of hoses made of two or more layers of thermoplastic plastics.

It is known to produce such hoses by the fact that Plastics melts, which melt under pressure in concentric layers squeezes, if necessary inflates with air or another gas and then cools.

The process of the invention is also used continuously Hoses made from two or more layers of different thermoplastics by melting the plastics, the melts into one another under pressure expresses concentric layers, if necessary with air or another gas inflates and then cools.

The method is characterized in that one from the melt first a massive stream with a core of one melt and one or several layers of the other melt lying concentrically around this core or melting and then forming the massive flow radially from its center expands to a tube.

In doing so, the flow rate of the layered one is preferably kept The current is so low that the flow remains essentially laminar.

If necessary, at least one of the melts can be pigmented.

Various thermoplastic Plastics are processed. Examples include: polyethylene with a Density of e.g. B. 0.920 to 0.960; Polypropylene; Polyamides; Polystyrene; Copolymers of styrene with other polymerizable monomers, e.g. B. with acrylonitrile; polymers fluorinated hydrocarbons, e.g. B. polytrifluorochloroethylene; Polycarbonates; Polyethylene oxide; Polyvinyl alcohol; Cellulose esters, e.g. B.

Cellulose acetate, cellulose propionate, cellulose butyrate; Polyacrylates and their copolymers; linear polyesters, e.g. B. polyethylene terephthalate; Polyvinyl chloride with or without the addition of plasticizers; Copolymers of vinyl chloride, e.g. B. with vinyl acetate or vinylidene chloride; synthetic rubber.

The thermoplastics used can optionally contain other substances to change their properties. These include for example plasticizers, fillers, pigments, dyes, antioxidants, antistatic agents, Stabilizers against the effects of light and heat and / or antiblocking agents.

The individual layers of the tubes produced according to the invention can thereby differ from each other differ in that they are thermoplastics contain or consist of various chemical compositions. One can but also plastics of the same chemical composition for the different layers, but different degrees of polymerization and thus different densities, different Use hardness, different viscosity and different optical properties. Finally, the individual layers can also differ from one another in that although they contain plastics of the same type, but different additives such as pigments, Plasticizers and the like, optionally in various amounts.

The pressure used to squeeze out the melts depends on the viscosity the melting and can fluctuate within wide limits, e.g. B. about 35 to 250 kg / cm2. This pressure must preferably be so low that the flow the melt remains laminar, e.g. B. with a Reynold number below 2100.

It is surprising that according to the method of the invention it is possible to manufacture hoses in which the thickness of the individual layers does not change over the entire length of the hose. It was also surprising that in this process the different masses do not mix, but rather form clearly separated layers.

According to the method of the invention, any hoses can be used Make each layer of diameter and very even wall thickness the wall is firmly connected to the neighboring one.

The wall thickness of the tubes can vary within wide limits and Z. B. 0.001 to 0.25 cm or more.

The adhesion of the individual layers depends on the type and the composition of the various masses. So z. B. layers of polyethylene, also from ethylene polymers of various degrees of polymerization, very firmly with one another tied together. Layers of z. B. polyethylene and polypropylene. Very different plastics, e.g. B. polyethylene and polyamide, least stick to each other.

This process can be used to produce various thermoplastic materials Combine properties in such a way that hoses with optimal properties are created.

You can z. B. a thermoplastic material with certain physical Properties, e.g. B. with good elasticity but poor clarity or a very narrow melting range, process together with another substance that z. B. has better optical properties or a wider melting range.

A tube with a three-layer wall made of these materials, in which the outer and inner wall layers e.g. B. are better transparent or have a wider melting range, while the middle layer of the wall consists of a fabric with high elasticity, is single-layer tubing in superior to many relationships.

The invention also relates to a device for performing the described procedure. This device is characterized by two or more Extruders, a cylindrical one connected to each extruder by a conduit Chamber, a so-called torpedo device arranged in this chamber with a central passage channel and one or more annular ones arranged around it Passage channels, the inlet openings of these channels with the associated Extrusions are connected, and one in front of an annular extraction nozzle centrally arranged cones.

A preferred embodiment of the device includes a means a valve pin to be closed measuring chamber through which the inflow of the molten Masses in the cylindrical chamber is controlled. The lower outer ends of this Measuring chambers can be flattened parallel to one another and parallel to the passage channel its lower extension is streamlined.

The nozzle assembly can have a conical cup and one in it Cups arranged conical tenons contain.

The drawings show, for example, embodiments of the invention Contraption.

F i g. 1 describes an apparatus for producing hoses made of two different thermoplastics; F i g. 2 to 13 show details this device; F i g. 14 shows individual parts of a device for production of hoses made from three different thermoplastic materials.

An extruder 10 is used to supply a melt 6 of thermoplastic Fabric that ultimately forms the middle wall layer of a tube 30 with three-layer Wall forms. The extruder 10 has a feed hopper 12 for receiving Grains or the like made of thermoplastic material, a conveying chamber 13 and a screw conveyor 14 for compressing, melting, mixing and conveying the mass into a perforated Crushing plate 18 as well as through this. The casing 19 also heats the extruder 10 heated oil or another suitable medium and heats the thermoplastic Mass when it is advanced from the hopper 12 to the discharge line of the screw press will.

A second extruder 20 is used to supply a melt 25 thermoplastic material comprising the inner wall layer 26 and the outer wall layer 27 of the hose 30 forms. The extruder 20 has a feed hopper 22 for Receiving grains or the like made of thermoplastic material, a conveying chamber 23 and a screw conveyor 24 for compacting, melting, mixing and advancing the molten mass to a perforated breaking plate 28 and through this. The jacket 29 heats the extruder 20 with heated oil or other suitable medium and heats the mass when it moves from the funnel 22 to the discharge line the press is advanced. Each press has a device P for measuring the pressure of the molten mass and a thermometer T for measuring the temperature thereof.

The molten mass from the extruder 10 is tapered by the Discharge line promoted to an elbow piece 32, which is connected to an inlet of the three-mouth Pipe section 34 is connected. Another inlet of this piece of pipe is with a vertical one Die holder 36 is connected to a cylindrical central passage opening 78.

A so-called torpedo device with several openings 75 is used to transfer the molten mass from the extruder 10 into a annular stream 16 and the molten mass from the extruder 20 into one annular stream 27, which surrounds the annular stream 16 outside, and one massive cylindrical stream 26 within annular stream 16. The torpedo device is located within the lower section of the central passage channel 78 in the die container 36 and extends downward through the tube 34.

The torpedo device 75, shown in FIG. 2 to 9 and 11 to 13 in more detail includes a cylindrical metal tube 80, the lower end of which is threaded engages in the bottom mouth of the pipe section 34, as well as a flange 83, which with the flanged portion of the elbow piece 32 on the extruder 10 mates.

A locking nut 82 secures the pipe 80 to the pipe section 34.

On the outer surface and near its upper end this exists Tube 80 from one piece with three attached there, arranged at the same distance streamlined star arms 81 for centering the pipe in the passage channel 78.

Concentrically within the tube 80 and attached to it by welding is an inner tube 84, on its outer surface and near its upper end three equally spaced streamlined star arms 85 are attached, to center it within the tube 80. It has one at the bottom Measuring chamber. The tube 84 has a central cylindrical passage channel 88 as well as a transverse channel 90 and is in communication therewith fitted inside the device with the tube 80 with an interference fit that the passage channel 90 of the measuring chamber with the passage 92 of the tube 80 and also with the middle Passage channel 76 of pipe section 34 is in alignment. The molten mass 25 flows from the second press 20 to the measuring chamber and becomes upon entry into the passage channels 92 and 90 distributed, with part of the flow as a ring in the passage channel 93 rises from the outer surface of the tube 80 and the inner wall of the passage 78 is formed, while the remainder of the flow is cylindrical in the passage 88 rises. A valve plug 86 is threaded into the outside The end of the pipe section 34 is firmly screwed in and arranged in the center of the passage 90. The thread moves the rounded end 87 of the valve pin 86 back and forth and regulates by reducing or enlarging the opening of the passage 90 the amount of mass 26, which forms the core of the stream, and mass 27, which passes through the annular passage 93 rises through and the outer layer forms.

The lower outer end walls of the measuring chamber at the lower end of the tube 84 are parallel to one another on two sides and to the passage channel 90 flattened, with its lower extension designed as a streamlined wedge which is the current fed there from the press 10 around the measuring chamber forks.

The F i g. 4, 5, 6 and 12 show that the flattened by the outer walls of the tube 84 and the inner wall of the tube 80 formed Passage channel 95 leads the two streams 16 ', 16 "around the measuring chamber and they are reunited to form a stream, which is formed as a ring in the upper extension of the passage 95 rises.

F i g. 3 shows a section near the flange 83.

The stream 16 is solid before it reaches the flattened lower end walls of the tube 84 touches. When the flattened end wall is touched, the current 16, as in FIG. Figure 4 shows bifurcated into two streams 16 'and 16 ".

Like F i g. 5 and 6 show the streams 16 'and 16 "are during their upward movement is kept separate from streams 26 and 27.

F i g. 7 shows that the concentric currents 27 and 16 by means of the Star arms 81 or are divided into three sections each while the stream 26 is its Massive river continues. When exiting the arm star section of the torpedo device 75 the three parts of the stream 27 unite again to form the outermost coaxial one Stream, the three parts of stream 16 combine to form the middle coaxial stream, and the massive stream 26 forms the inner core of a composite concentric massive current according to the cross section in FIG. 8. Under high pressure this becomes massive flow upwards in the cylindrical through-channel78 to an annular one Ausziehdüsenaggregat 38 moves, with this pressure the individual layers of the various firmly connects coaxial currents.

The annular nozzle assembly contains a conical cup 41 as well as the conical pins 40 hanging down at a distance therefrom to form an upwardly tapering annular passage channel 37 through which the thermoplastic material from the cylindrical passage channel 78 to the annular Extraction nozzle 42 is guided. The bottom part of the nozzle assembly 38 has a flanged one Socket which mates with a flanged end portion of die holder 36, and is firmly connected to this by means of bolts not shown. Although the drawings show a tapered passage 37, a canal can also be successful use with parallel walls.

Moreover, the depending pin does not need a sharp one Pointed to end, but can be designed as a truncated cone with a circular face be. Alternatively, instead of the pin 40, a cylindrical core piece can also be used use. The concentrically layered massive stream according to FIG. 8 is by means of the tip of the cone 40 divided radially and thereby outwards into the passage channel 37 out, the exact coaxial stratification according to FIG. 9 is preserved, also when pulling out through the annular nozzle mouth 42 and a cross section through the wall of the hose 30.

The hose 30 emerges from the nozzle mouth 42 in a warm, malleable manner State off and is by means of a gaseous medium, such as. B. air or a other gas inflated and stretched radially. The gas is under regulated pressure fed through line 46 and an orifice 44 in pin 40.

The inflated tube 30 is reversed by means of a pair rotating nip rollers 48 and 50 pulled upward. The hose 30 passes through when it is pulled away from the extraction die, a rotating ring 52 that a Cooling gas blows ring-shaped from the outside onto the hose wall in order to cool the plastic and solidify.

The rotating ring 52 is on an annular cylindrical housing 54 rotatably mounted. This is the cooling gas by means of a plurality of fans 56 fed. The ring 54 is moved on its surface by the drive belt 58, which is driven by a motor 60 with a reduction gear.

The extraction nozzle 38 and the air ring housing 54 are on cross arms 62 of the machine frame 64 stored.

The nip rollers 48 and 50 have a shaft extension at each end, which is rotatably mounted in bearings 66 and 70 on transverse arms 68.

The rollers 48 and 50 maintain the gas pressure in the hose 30, press the hose together and guide it in a flat band shape 72 by means of guide rollers 74 to a reel, where it is wound up.

The following examples describe the manufacture of double-walled and three-walled hoses. The working conditions and the properties of the hoses can be found in the table at the end.

Example 1 In a device according to FIGS. 1 to 13 became a Hose made with a double wall. The extruder 10 was made a mass of 3.5% carbon black and 96.5 ° 0 polyethylene with a melt index of 2.0 (ASTM-D 1238-52 T) and a density of 0.92, the extruder 20 made a mass 5.00 / 0 titanium dioxide and 95.0 0/0 of the same polyethylene are supplied. While undressing the valve pin 87 was closed.

The resulting tube with an average wall thickness of 0.09 mm was opaque. The inner layer of the wall was black, the outer white; the black one Color was not penetrated to the outside.

Films made from this tube could be used as a self-supporting sheathing and packaging materials for photographic films and for darkening windows be used. The two layers of the hose wall adhered so tightly together that they did not peel open even when bent repeatedly.

Example 2 In the device according to FIGS. 1 to 13 became a Hose made with a three-layer wall. The middle layer passed Made of polyethylene with a melt index of 5.0 and a density of 0.960, the two outer layers made of polyethylene with a melt index of 2.3 and a density of 0.923. The outer and inner wall layers were of the same thickness.

Films made from this tube were stiffer than films of the same thickness, which were made only from the material of the outer layers. The films could but within a wider range of temperatures, pressures and contact times are heat sealed as films made only from the material of the middle layer were manufactured.

Example 3 Following the procedure described in Example 2, a Hose made with a three-layer wall. The middle layer passed Made of polyethylene with a melt index of 1.5 and a density of 0.937, the two outer layers made of polyethylene with a melt index of 2.3 and a density of 0.923.

Films made from this tube had better gloss and better Clarity as films of the same thickness made only from the material of the middle class were made.

The films could be used as heat-sealable packaging material for Foods are used. The three layers stuck together so tightly that they did not peel open even with repeated bending.

Example 4 Following the procedure described in Example 2, a Hose with a three-layer wall manufactured. The middle layer passed made of polypropylene with a melt index of 5.0 and a density of 0.910, the two outer layers made of polyethylene with a melt index of 2.3 and one Density of 0.923.

Films made from this tube had better optical properties than Films of the same thickness made only from the material of the middle layer. They could be used as heat-sealable packaging for food.

Example 5 Following the procedure described in Example 1, a Hose made with a double wall. The inner layer existed made of polyamide (nylon-6), the outer made of polyethylene with a density of 0.920.

Films from this tube could be used for packing greasy, oily or the same material can be used, the layer consisting of polyamide was facing the packaged material.

The number of layers, their composition and their structure in hoses with multilayer walls and the type of polymer in each wall layer are essentially determined by the desired properties of use. Each layer can be formed from a different polymer if desired. For example, a tube with a three-layer wall with different polymers in each wall can easily be passed through the device according to FIG. 14, where each of the three extrusion presses conveys a different polymer coaxially into a single common passage channel which ends in an annular drawing nozzle assembly provided with a single cavity. If more than three wall layers are desired, the one shown in FIG. 14 can be modified by adding the desired number of extrusion presses. Example no. Comparative comparative I II III IV V hose hose Extrusion press 10 Pipe diameter (cm) ......... 6.35 6.35 6.35 6.35 6.35 6.35 8.9 Auger 14 (rpm) .......... 14 70 85 51 35 15 Pipe temperature (° C) 190! 205 1 205 1 205 j 205! 205 l 260 melt Temperature (° C) 185.0 200 200 200 200 1 200 1 250 Pressure (kg / cm²) ............. 145 105 175 180 135 110 310 Extruder 20 Pipe diameter (cm) ......... 3.8 3.8 3.8 3.8 3.8 3.8 3, Auger 24 (rpm) .......... 21 3.8 3.8 3.8 45 1 38 Pipe temperature (° C) 190 190 205 204.4 1 246.1 melt Temperature (° C) ............ 185.0 185.0 200 190 200 Pressure (kg / cm²) ............. 42 42 42 42 210 Pipe section 34 Temperature (° C) .............. | 190 | 205 | 205 | 205 | 230 | 230 | 260 Example no. Comparative comparative 1 II hose III hose IV V Drawing nozzle 38 Temperature (° C) .............. | 190 | 205 | 205 | 205 | 230 | 230 | 260 Mouth 42, diameter (cm) 15 15 30 30 15 15 j 15 Gap width (cm) ............... | 0.046 | 0.046 | 0.046 | 0.046 | 0.046 | 0.046 | 0.046 Hose 30 Diameter (cm) 46 51 42 42 34 34 29 Wall thickness (mm) Inner layer 26 ............ - 0.011 - 0.002 - 0.008 0.019 Middle layer 16 ........... 0.045 0.003 0.025 0.017 0.032 0.016 0.038 Outer layer 27 ............ 0.045 0.011 - 0.002 - 0.008 0.019 Physical Properties Haze (ASTM-D 1003-59T). . . 7.5 5.5 3.2 45.8 10.1 - Gloss (45 ° Gardner photometer) 1 75 64 78 14 58 Module at 1 0 elongation (1 102 kg / cm2) MD .......... 2.7 3.8 3.3 11.4 6.8 - (ASTM-D1530-58T) TD ....... 41 60 38 160 84 - Claims: 1. A process for the continuous production of hoses from two or more layers of different thermoplastic plastics, in which the plastics are melted, the melt is pressed out under pressure in concentric layers, if necessary inflated with air or another gas and cooled, characterized in that, that from the melts initially a massive flow is formed with a core of one melt and one or more layers of the other melts lying concentrically around this core and then the massive flow is expanded radially from its center to the tube.

Claims (1)

2. The method according to claim 1, characterized in that the Keeps the flow velocity of the stratified stream low, thus the flow remains essentially laminar. 3. The method according to claim 1 or 2, characterized in that at least one of the plastic melts is pigmented. 4. Device for performing the method according to one of the claims 1 to 3, characterized by two or more extrusions (10, 20), one with each extrusion press via a line bound cylindrical chamber (36), a So-called torpedo device (75) arranged in this chamber with a central Passage channel (88) and one or more annular ones arranged around it Passage channels (83), the inlet openings of these channels with the associated Extrusions are connected, and one in front of an annular extraction nozzle centrally arranged pin (40). 5. Apparatus according to claim 4, characterized by a means a valve pin (86) to be closed measuring chamber through which the inflow of the various molten masses in the cylindrical chamber (36) is controlled. 6. Apparatus according to claim 5, characterized in that the lower outer end walls of the measuring chamber are flattened, with its lower extension is streamlined. 7. Device according to one of claims 4 to 6, characterized in that that the nozzle unit has a conical cup (41) and one in this cup arranged conical pin (40) contains. Documents considered: Belgian patent specification no. 531 375.