CH648145A5 - ELECTRIC AND WAVE GUIDES COVERED WITH CURLED POLYMERS. - Google Patents

Description

The invention relates to electrical conductors and waveguides coated with cellular polymers, which are used in particular to transport energy such as electrical current or electromagnetic waves, and to a method for producing the same.

It has long been known to surround conductors which are used for the transport of electrical current, be it direct current or alternating current or for the transmission of electromagnetic waves, with insulation in the form of a sheathing. The conductors can be covered with a thin insulating lacquer film, it is also possible to cover the conductors with thin strips, e.g. wrapped in paper or plastic; predominantly, however, efforts have been made to use foamed plastics, i.e. to apply expanded polyme-io re.

In the production of such sheaths, the procedure is generally such that an extrusion tool is used to apply a foamable mixture to the conductor which is passed at the same time. One can proceed in such a way that a solid blowing agent such as e.g. Azodicarbonamide and often also so-called nucleotors and possibly other additives are incorporated and the plastic expands under the action of heat, the blowing agent decomposing to form gas.

2o As a blowing agent, gases such as nitrogen, air, argon, helium or CO 2 can also be added to a plastic melt under pressure, whereby the gases can be dissolved in the melt. Gaseous organic compounds such as methane and ethane as well as corresponding halogenated hydrocarbons such as dichlorotetra-fluoroethane, ethyl chloride etc. have already been recommended as blowing agents.

By using polystyrene as a polymer, it is possible to drive the air pressure in the jacket very high to about 95%; the disadvantage, however, is that polystyrene has a very low elasticity. In addition, it is difficult to produce a foam body that has very uniform voids. Finally, it is very difficult to produce a foam in this way, which has a very large number of very small cavities, especially those in the size range of a few (on and below).

Attempts have been made to improve foamed insulation for electrical conductors by using other polymers or by using polymer mixtures, e.g. io is described in DE-AS 1 029 896, according to which a foam-like mixture of butyl rubber with polyethylene is used for insulation. In addition to attempts to achieve the sheathing of conductors by improving the polymers and blowing agents and nucleating agents 45 used, attempts have also been made to achieve more advantageous sheathing by apparatus and process improvements.

For example, DE-OS 2 545 931 describes a method by which the plastic insulation arrives immediately after leaving the spray head in an expansion space under a residual pressure of about 5 Torr. This method works with several chambers, it is also necessary to apply a film of lubricant to the insulation; finally the insulation still has to be calibrated.

Although numerous methods for sheathing conductors are already known, there is still a need for improved sheaths for electrical conductors and waveguides, which in particular have a high degree of curl, are distinguished by good insulating and dielectric properties and, moreover, have good mechanical properties.

The object of the invention is therefore to provide sheaths for electrical conductors and waveguides, which are distinguished by a degree of curl of at least 60% and in particular have a high proportion of very small cells, and are preferably both highly uniform in both transverse and longitudinal directions

3 648145

award. It is also an object of the invention to provide an um mixture which, in and of itself, only consists of two im-mantle layers, which in particular consist of notably pure, uniform substances, so it should be excellent insulating and frame with a small wall thickness In the invention, the term binary system does not have dielectric properties that are free from interfering strictly on mixtures of only two pure uniform

Additives are and which can also be applied through excellent substances. The average person skilled in the art has mechanical properties such as electricity and strength that a polymer substance is made up of a variety of mo

distinguish them so that they mechanically protect the conductor.

can. is set, therefore such polymers are with an appropriate

This object is to be regarded as a component by molecular weight distribution surrounding cellular polymers within the scope of the invented electrical conductors and waveguides, the same also applies. Claims 2 to 5 give particularly advantageous copolymers. In certain circumstances, embodiments can again. According to the invention, a single-phase mixture with an inert solution is used to produce these polymer mixtures, such as a uniform component, electrical conductor and waveguide; form in the claims 7 means and below the critical temperature to 15 particularly advantageous embodiments will separate temperature into two liquid phases.

described this procedure. The liquid does not necessarily need to be completely pure

The cladding is made of unexpanded porous line and to represent a completely uniform substance

Aren polymers can be done in different ways. len. So it often does no harm, even if smaller quantities

According to one embodiment of the invention, impurities, and possibly also proportions of homologous linear, in particular fiber-forming, macromolecular substance compounds, as are produced by large-scale production

zen, especially synthetic polymers are used, which are necessary to be present.

e.g. by polymerization, polyaddition or polycondensation- For practical implementation, the two will be obtained. The prerequisite is that the polymer components can be melted at the required temperatures, i.e. produced in the liquid state without a mogen mixture. This can pass over in the way of decomposition and can mean that the inert liquid with the comminuted liquid forms a binary system, which mixes in the liquid polymer and, at appropriate temperatures, a state of aggregation completely Miscibility heats up, providing for appropriate mixing and also becoming one in the liquid state.

Area with a mixture gap. A further possibility is that the two systems of this type have a 30 component separately brought to the required temperature for the liquid state. Phase diagram is brought about in the manner, for example, in the text and the two components in the desired quantity book of Physical Chemistry S. Glasstone, Macmillian ratio just before extrusion continuously mixed with-and Co. Ltd., St. Martins's Street, London 1953 on page 724. This mixing can be reproduced in a pen for the Aniline Hexane system. Take place in this mixer, which is expediently completely miscible between the dosing diagram for the two components above the pumped for the individual components and the dosing pump curve. Below pe is arranged for the mixture. A subsequent Ho-der curve, two liquid phases in equilibrium with one another can be recommended.

Weight. In many cases, it is advisable to mix through the homogeneous mixture

For the feasibility of the invention, it is not essential to apply a suitable vacuum before the extrusion that the two coms are vented in the 2-phase range.

Components still have a considerable solubility compared to the ratio of polymer to inert liquid in that of the other components, as in the above mass can be varied within wide limits. The mentioned diagram is the case. In many cases, it is sufficient if the ratio of polymer to inert liquid in the liquid 2-phase region is marginally soluble, and the degree of curling is controlled to a large extent. It is essential, however, that the two components become 45.

liquid state two liquid phases next to each other In general it is sufficient if the temperature of the ho-form. In this respect, these systems differ from such a mogeneous mixture before extrusion by only a few degrees, in which the dissolved polymer precipitates directly as a solid substance when the temperature drops below the critical temperature or above the demixing temperature, without initially corresponding to the respective temperature the cooling is the liquid state of aggregation so settling.

run through. By enlarging the difference between the temples within the scope of this embodiment, the usual temperature of the homogeneous mixture to be extruded and the meltable polymers can be used, such as the polymers obtained by poly-segregation temperature, but also interesting merization-obtained polymers, polyethylene, polypropylene, effects with regard to the structure of the casing . Polyvinyl chloride, polyacrylates, polycaprolactam and ent 55 The homogeneous mass can then be used by means of a conventional talking copolymer, etc. ; Polycondensation polymer extrusion tool are extruded, wherein the to um-like polyethylene terephthalate, polybutylene terephthalate, poly-sheathed conductor is usually also drawn through the extrusion amide-6.6, polyphenylene oxide and polyaddition polymers such as tool. For covering the conductor with polyurethane and polyureas. usual tools, such as

In principle, suitable inert liquids are those known to the plastics expert, e.g. also so-called men of the invention all those liquids which form a binary system of the type mentioned above on page 237 to polymers in the liquid state with the so-called wire sheathing quill, as polymers in the liquid state. Inert to polymer trusion, BASF 1971 may be mentioned.

indicates that the liquid does not work within a short period of time. Significant degradation of the polymer can occur in the period of time, or reacts with the polymer itself, according to the book "Kunststoff-Extrudertechnik" published by Carl Hanser. Munich 1963 by Dr.-Ing. Gerhard Schenkel, page 354 ff.

If the state diagram mentioned above is also taken.

of the system aniline / hexane the conditions for a binary The cooling of the extruded and applied to the conductor

648145

4th

brought mixture can happen in different ways. is when the polymers are applied to the coating to be coated, it is possible to cool only with air and the polymer conductors according to the invention are not the case; The coated conductor has no or only a slight change in volume, which can be more or less due to the decrease in the temperature when the tool is cooled or after it has passed through, even immediately after leaving the part serving for the coating.

into a bath. In the context of the invention, the cellular polymers serve

The cladding, after cooling by cooling as a cladding of conventional electrical conductors and solidifying, with an appropriate extractant waveguides, i.e. conductors are sheathed, which are washed out. A number of electrical current transports such as direct or alternating

Solvents such as acetone, cyclohexane, ethanol, methyl 10 can be used.

enchloride and others as well as mixtures of such liquids. The sheathing can also be used with conductors,

is suitable. that are used to transport the usual electromagnetic waves

A suitable device for making a mass, e.g. for telephone cables, in the area of high-frequency

which is used for sheathing the conductor by extrusion, technology etc. Also optical fibers, e.g. Glass fibers can be explained in more detail in FIG. 1. 15 are encased.

1 is a thermostattable container, of which the inert. The conductors can be made of common metals such as copper and liquid via a double-piston pump 3 and a wide alloy. Of course, a heater 4 can also be metered into the mixer 8. The heater 2 other metal e.g. Aluminum etc. Also used for preheating. Other materials that conduct waves, e.g. Glass can be placed over an extruder 6 and a gear pump 7 Polypropy-20.

len, into the mixer 8, from which via a gear pump 9 The conductors can be in conventional forms, e.g. as

Tool 10 is fed through the simple wires, multiple wires etc. for the purpose of sheathing

a wire-shaped conductor 11 is guided.

In the context of the embodiment described above, it was particularly surprising that the inventions

polypropylene is preferred as the polymer. It is possible for the Po 2s to use highly flexible, elastic forgiving

lypropylene, other polyolefins, especially polyellations for electrical conductors and waveguides, are available.

ethylene and polymethylpentene can be added. To be put as inert, in addition to good mechanical properties

Liquids are particularly suitable N, N-bis (2-hydroxy- as well as good strength, elongation and high fatigue resistance

ethyl) -hexadecylamine, glycerol monoesters such as glycerol fatigue also good insulating and dielectric properties nolaurat. Own 30. This means that they can be used wherever the electrical

The cooling conditions not only allow the • tric properties of the casing to arrive, they are

The structure of the inside of the casing varies, but it is also useful if, e.g. in the case of glass fibers, which may be the case, the properties of the surface of the sheathing should act as mechanical protection,

to influence. In this way, smooth surfaces can be obtained. The pores of the cellular material are very uniform, but they still have a certain number of pores, 35 and are extremely fine. The homogeneity of the cell structure is when a bath is used for cooling that the inert is not only very good in the transverse direction but also in the longitudinal direction.

Contains liquid that is also in the direction to be extruded. The jackets can also be very mixed. thin conductors are applied. A calibration is in the

If air or a bath that generally contains another liquid is not necessary.

holds, used for cooling, so predominantly closed 40- The polymers can surfaces in the verses according to the invention. drive with extremely simple process technologies

The proportion of the smallest cells will be brought about by rapid, no more high pressures are required. ■

cooling increased. There is also practically no density and thickness fluctuations

Under degree of curl in the context of the invention, the gene is more on. The outside diameter remains practically unchanged during the volume fraction of cavities in relation to the production.

total volume of the polymer structure, i.e. It is particularly advantageous for the sheathing to be understood in accordance with the invention. In addition to conventional methods for determining methods, it can be worked without additives such as nucleators, blowing agents for pores or cells in plastics in a simple manner, etc., as a result of which a very uniform manner can also be determined by weighing the weight and the stable sheathing is achieved. Since the ummante volume of a pelletized body determines from what the 50 lung can be very thin and also extremely thin conductors of apparent density. From the actual density of the sheathed, it is possible to combine a variety of reused polymers and the weight of the sheathed conductors in a very small space. Since the actual volume of the polymer and the void fraction a very high degree of corrugation is possible, the self-calculation has to be carried out, whereby the weight of the air, which is important for the cells, is very low. The flexibility is full, can be neglected. 55 awarded.

The cells or pores can be rounded or elongated. The polymers can be used to coat a variety of

Having shapes and using regular and irregular numbers of conductors that are of various shapes, they are generally used by more or less problems. So conductors can

niger strong cell walls separated from each other. The individual who are used to transport equality and alternation

Cells can flow in through channels or other openings. Corresponding waves are very advantageously connected. They are also completely closed conductors in high-frequency technology, in telecommunications

ne cells possible. technology and in the transmission of electromagnetic

Non-expanded in the context of the invention means waves used in general. It is also possible to

that the cell structure is not covered by the same when winding the same coil winding wires. Also at

The use of blowing agents to expand the plastic 65 conductors for optical transmission methods are the

is obtained. In such processes, sheathing is very suitable.

Preserve foam structure and the volume of the extrusion. Since the sheathing is extremely uniform, the doped mass has increased. Such a volume change waveguide also has a favorable damping behavior, so

that there are no characteristic impedance deviations and very good transmission properties are achieved.

The loss factor is very low, which is particularly advantageous at high frequencies. The loss angle is also favorable. The sheath resistance is very good.

It is not necessary to heat up the conductor before applying the sheathing.

The invention is illustrated by the following examples.

example 1

From an extruder, melted polypropylene is brought into a mixer via a metering pump. At the same time, 840 grams per hour of N, N-bis (2-hydroxyethyl) hexadecylamine are preheated to 145 ° C. in a heater via a second metering device and likewise fed to the mixer.

The mass is homogenized at a mixer speed of at least 200 rpm and a temperature of 220-240 ° C. The mass is fed into the sheathing tool, which is heated to 180 to 200 "C, by means of a gear pump.

Here is the wire running off an unwinder

5 648 145

covered with the molten mass during the passage through a nozzle.

At a passage speed of 10 m / min, after passing through an air gap of 5-10 mm, the wire is passed into a water bath in which the sheath solidifies.

Example 2

A raw cable obtained according to Example 1 is removed in a soxhlet by extraction with alcohol.

Example 3

A raw cable obtained according to example 1 is continuously passed through a series of ultrasonic baths, each of which is filled with 15 alcohol with bath liquid. After 6 to 8 bath passages of 3 minutes each, the curling agent is washed out.

Example 4

20 The removal of the bulking agent according to Example 2 or 3 is carried out instead of alcohol with methylene chloride.

C.

1 sheet of drawings

Claims (15)

648145 1. Electrical conductors and waveguides coated with cellular polymers, characterized by a covering made of non-expanded, porous, linear polymers with a degree of curling of at least 60%. 2. Sheathed electrical conductor and waveguide according to claim 1, characterized by a sheathing with a degree of curl of 70 to 85%. 2nd PATENT CLAIMS 3. Sheathed electrical conductor and waveguide according to one of claims 1 or 2, characterized in that the cells are smaller than 10 (in diameter and at least 50% of the cells have a diameter of less than 1 µm. 4. Sheathed electrical conductor and waveguide according to one of claims 1 to 3, characterized by a sheathing made of polypropylene. 5. Sheathed electrical conductor and waveguide according to one of claims 1 to 3, characterized by a sheath made of a mixture of polypropylene and other polyolefms. 6. A process for the preparation of electrical conductors and waveguides coated with cellular polymers according to claim 1, characterized in that a homogeneous mixture of at least 2 components, one component being a meltable polymer and the other component being a liquid which is inert to the polymer, and Both components form a binary system which, in the liquid state of aggregation, has an area of complete miscibility and an area with a miscibility gap, applies it to the conductor at a temperature above the separation temperature, then cools down and solidifies the polymer structure formed. 7. The method according to claim 6, characterized in that a bath is used to cool and solidify the casing. 8. The method according to claim 7, characterized in that the bath contains the inert liquid of the extruded component mixture. 9. The method according to claim 7, characterized in that the bath contains water. 10. The method according to any one of claims 6 to 9, characterized in that the polymer structure obtained is washed out after solidification with a solvent. 11. The method according to any one of claims 6 to 10, characterized in that the homogeneous mixture is applied to metallic conductors. 12. The method according to claim 11, characterized in that the homogeneous mixture is applied to metallic conductors in the form of wires. 13. The method according to any one of claims 11 to 12, characterized in that the homogeneous mixture is applied to metallic conductors made of pure or alloyed copper. 14. The method according to any one of claims 11 to 13, characterized in that a coating with a wall thickness of 0.05 to 2 mm is applied. 15. The method according to claim 14, characterized in that applying a casing with a wall thickness of 0.05 to 0.5 mm.