Cable covered with foam plastic insulation incorporating polymeric material characterized in superhigh degree of extrudate swelling

FIELD: electrical communication components; cables whose conductors are covered with polymeric insulation extruded about conductor.

SUBSTANCE: proposed cable has its conductors covered with insulation that has at least one component incorporating maximum 20, and best of all 15, mass percent of polymer characterized in high degree of extrudate swelling. This polymer is defined as that characterized in extrudate swelling degree over 55% and higher, best of all that having extrudate swelling degree over 65%. Best insulation has at least second component of high degree of cracking resistance under stress; therefore, minimal combination of these polymers will provide for insulation layer possessing unique combination of physical properties, including high degree of foaming, fine uniform cellular structure, reduced attenuation, and cracking resistance under stress which is capable of sustaining temperature of 100 °C over 100 h without cracking in spirally coiled state at stress level one-fold higher than outer diameter of insulation.

EFFECT: improved electrical characteristics and mechanical strength of insulation.

23 cl, 6 dwg, 3 tbl

 

The present invention in General relates to communication cables, and in particular to cables with a highly expanded foam with uniform, small and closed cellular structure.

According to U.S. patent No. 4547328 and 4683166 - Yuto and Suzuki: the introduction of at least 20 wt.% plastic with a degree of swelling of the extrudate (SRI)equal to 55% or more in the mixture of polymers gives some advantages in the manufacture of coaxial cable. In particular, the introduction of the polymer with SRA 55% or more increases the elasticity of the molten polymer, resulting in easier regulation of the process of coating wire foam insulation. According to the mentioned documents these advantages give a high degree of foaming (expansion ratio) and the cellular structure of the foam, the size of which is 50 μm or less. Fine cellular structure with high coefficients of expansion are desirable for reducing electrical losses (attenuation), reduce material consumption and to increase mechanical strength. Specialists in the art it is known that in the prior art it is necessary to limit the material with SRA equal to 55% or more, at least 20 percent of the entire mixture, to provide the desired cellular structure, high coefficient of expansion and resistance to cracking under stress. But to increase when labilnosti dimensions and mechanical strength of the cable layer of foam insulation covered nesperennub continuous layer or film of polymer. It is known that the presence of this layer complicates the manufacturing process and increases the cost and increases the flow of materials. In addition, the materials themselves high SRA have disadvantages from the electrical point of view, and this fact affects the electrical purity (dissipation factor) of cable.

The present invention provides such electrical connection elements as wires and cables, which combine low dissipation factor and high resistance to accelerated high temperature cracking under stress or in a solid or, preferably, in the foamed state. This non-novel combination of properties provides the following special and advanced features at the same time in the same structure:

- High degree of foaming - at least 50%, and more preferably from 50 to 85%.

- Structure of the foam with a fine and uniform cells, closed, with a preferred size of less than 100 microns, providing good resistance to mechanical compression.

- Resistance to accelerated high temperature cracking voltage withstand tests on the length of the normal in the industry of life: more than 100 hours stand without disturbing the working condition of a temperature of 100°in turn the Ohm in a spiral state at the voltage level, 1 times the outer diameter of the insulation.

The level of attenuation below the level possible according to the realizations of the prior art, which require less electrically high characteristics of SRA over 55% when the ratio of the mixture is at least equal to 20 wt.%.

- Reduced weight of plastic, therefore reducing the cost of communication compared with elements of communication prior art of similar purpose and end use.

According to the invention proposed electrical connection element containing the wire and the surrounding foam insulation. Foam insulation contains no more than 20 wt.% polymer having ultra high SRA - above 55%. The polymer is ultra high SRA preferably mixed with one or more electrically and/or environmentally more perfect additional polymer compositions to provide the desired mechanical, electrical, thermal and durable properties and performance costs, which were hitherto not been possible at the same time in the same implementation. In particular, additional polymer compositions have a high accelerated high temperature stability, defined by the oxidizing time of induction (the warriors) more than 15 min at 200°according to the method 4568 ASTM standard. More preferably, the l is a comparative polymer composition provided time oxidizing induction longer than 20 minutes

Additional polymer composition preferably has a dissipation factor less than the polymer with ultra high SRA, and less than 75 microradian, and more preferably less than 50 microradian.

The isolation provided by the invention has a resistance to accelerated high temperature cracking under tension over 100 hours at 100°in rolled into a spiral state when the voltage level of 1 times the outer diameter of the insulation, without the appearance of radial or longitudinal cracks.

According to one preferred aspect, the foam insulation contains about 15 wt.% olefin polymer with a value of SRA above 55%. According to another preferred aspect, the foam insulation contains no more than 20 wt.% low density polyethylene with SRA above 55% and at least one additional polyolefin composition having high accelerated high temperature stability, as defined by the soldiery longer than 15 minutes at 200°according to the method 4568 ASTM standard. At least one additional polyolefin composition preferably has a diffusion coefficient lower than that of low density polyethylene with high SRA, and less than 75 microradian.

Insulated electrical connection element according to the present invention can be implemented in various types of structures used by the s for telecommunication as coaxial cables, phone taps or twisted pair cables.

According to another variant implementation of the present invention proposed an electrical communication cable containing the wire and the surrounding foam insulation. Foam insulation contains a mixture of the first polyolefin with ultra high SRA is higher than 55%, is present in an amount of not more than 20 wt.%, and at least an additional polyolefin, having high accelerated high temperature stability for longer than 15 minutes at 200°according to the method 4568 ASTM standard.

At least one additional polyolefin preferably has a diffusion coefficient lower than that of the polyolefin with ultra high SRA, and less than 75 microradian. Additional suitable polyolefin may be any having a high level of stability of the polyolefin containing phenolic antioxidants and/or mixture of phenolic antioxidant phosphite, and also light collection spatial-obstructed amines.

The above are some of the features and advantages of the present invention, other features and advantages will become apparent from the following detailed description and from the accompanying drawings, on which:

Figure 1 - image in the perspective of the local section, showing a coaxial cable according to astasia invention;

Figure 2 - the picture in perspective of the local section, showing the subscriber tap according to the present invention;

Figure 3 - image in the future twisted-pair cables according to the present invention;

Figure 4 is a photograph showing a sample of the accelerated high temperature stress cracking prior to the test;

5 is a photograph showing a sample of the accelerated high temperature stress cracking after testing to the level of occurrence of violations with visible cracks; and

6 is a graph showing how the attenuation in the cable affects the dissipation factor of the composition of the insulation.

The present invention is described below in more detail with reference to the accompanying drawings that show some, but not all, embodiments of the invention. It is obvious that the invention can be implemented in many different ways, and it should not be construed as limited presented here options of implementation; rather, these embodiments of the invention are proposed so that this disclosure of the invention satisfy applicable legal requirements. Throughout the document similar reference signs refer to similar elements.

Figure 1 shows an insulated electric element of the ligature according to the present invention, made in the coaxial cable 10. The coaxial cable includes a core 11 of the wires of the cable which includes an inner conductor 12 of the respective electrically conductive material and surrounding a solid cylindrical wall of the expanded foam dielectric material 14. The insulator 14 is an expanded cellular foam composition. Cell dielectric 14 preferably have the configuration of a closed cell, uniform size is typically less than 200 microns in diameter, and more preferably less than 100 μm. The foam dielectric 14 preferably has adhesive or frictional coupling with the inner conductor 12 by a thin layer of adhesive or friction material 13. Inner wire 12 may be formed from solid copper, copper tube, stale-copper, aluminamedia or other hollow wires or twisted configuration. Internal wire preferably has a smooth surface, but may also be corrugated. In the illustrated embodiment of the invention shows a single inner wire 12, but it is understood that the present invention is also applicable to cables having an inner wire number more than one, isolated from each other and forming part of the core 10. In addition, according to the illustrated variant implementation of izobreteny the inner wire 12 is a wire of aluminum core 12A with an outer copper layer 12b of the shell.

In conformance to the core 11 around it made a solid smooth tubular sheath 15. In the preferred illustrated embodiment of the invention the tubular shell 15 is made of aluminum strips, formed in a tubular configuration, and in which the opposite side edges of the strips are butt-jointed to each other, with located the butt edge continuously connected by a continuous longitudinal weld 16. Welding can be performed essentially in accordance with U.S. patent No. 4472595 and 5926949, the contents of which are hereby incorporated by reference. The above-mentioned running the shell 14 of the longitudinal welding is preferred, but experts in the art it will be clear that for the manufacture of mechanically and electrically continuous thin-walled tubular metal shell can be applied in other ways. The inner surface of the tubular shell 15 is preferably continuously coupled along its length and on its circumference with the outer surface of the foam dielectric 14 a thin layer of adhesive 17. A preferred class of adhesives for this is a random copolymer of ethylene and acrylic acid (EAS), or (EAS) in a mixture with other compatible polymers. The outer surface of the shell 15 is surrounded by a protective jacket 18. Appropriate formulations for external protective jacket 1 include thermoplastic coating materials as polyethylene, polyvinyl chloride, polyurethane and rubber. According to the illustrated variant of the invention, the protective jacket 18 is preferably coupled to the outer surface of the shell 15, the adhesive layer 19 to increase flexion artificial coaxial cable. The adhesive layer 19 is preferably a thin layer of such adhesive as EAS-copolymer and the above-mentioned mixture. The drawing shows the adhesive layer 19, but the protective sleeve 18 can also directly associate with the outer surface of the shell 15.

Figure 2 shows another example of the electrical connection element according to the present invention, implemented in the subscriber tap 20, the type of which is used for transmitting the RF signals as television signals, satellite signals; signals, data, cell phone, etc. the Cable 20 includes a core 21 of cable cores having an elongated inner wire 22 and the dielectric layer 24 surrounding the inner conductor. Dielectric layer 24 is preferably connected with the inner wire 22 of the adhesive layer 23 made, for example, of a copolymer of ethylene-acrylic acid (EAS), ethylene-vinyl acetate (EVA) or ethylene-methyl acrylate (EMA). The inner wire 22 is preferably made of stale-copper wire, but you can also use another conductive wire (such as copper). Dielektricheskikh 24 is a foam polymer, continuous from the inner conductor 22 to the adjacent layer above, but also may have an external continuous layer or shell. Conductive screen 25 is made around the dielectric layer 24. Conductive screen 25 is preferably connected with the dielectric layer 24 and adhesive layer 26. The adhesive layer 26 can be made of any material referred to above in connection with the adhesive 23. Conductive screen 25 prevents leakage of signals transmitted by the inner wire 22, and screens interference from external signals. Conductive screen 25 is preferably made of masking tape, which passes longitudinally through the cable. The shielding tape is preferably longitudinally so that the edge of the masking tape or abut end-to-end to each other, or are imposed on each other to provide 100% shielding. More preferably: a longitudinal edge of the masking tape overlap. Shielding tape has at least one conductive layer, such as a thin layer of metal foil. The shielding tape is preferably coupled layered tape containing polymer inner layer with a metallic outer layers, and connected with the opposite sides of a polymer of the inner layer. Polymer inner layer usually one is camping polyolefin film (e.g., polypropylene) or a complex of the polyester. The metal layers are typically thin layers of aluminum foil. Many elongated wire 27 is surrounded by an electrically conductive screen 25. Extra long wires 27 preferably form the braid 28, but they may also overlap each other in two directions, can be unidirectional or may be located alternately (for these locations in the industry use SZ and ROL). Extra long wires 27 are metal and preferably made of aluminum or aluminum alloy, but they can also be made of such a suitable material such as copper or copper alloy. Shirt 29 surrounds the cable braid 28 and protects the cable from moisture and other environmental influences. The jacket 29 is preferably made of non-conductive material such as polyethylene or polyvinyl chloride. It should be mentioned that several elongated layers of foil shields and several elongated layers of elongated wires, you can mix and match with each other to provide additional electrical shielding and/or mechanical strength.

In Fig. 3 shows another electrical connection element according to the present invention, located in the cable 30 with numerous pairs of wires. The cable 30 has a tubular jacket 31 to the blanching, surrounding the four twisted pairs of insulated wires 32, 33, 34 and 35. The jacket 31 is made of a flexible polymeric material and preferably made by extrusion from the melt. For this you can apply any polymeric material that is normally used for the manufacture of the cable. Each insulated wire in the twisted pair has a conductor 36 by a layer of insulating material 37. The wire 36 may be a metal wire or any well-known metal wire used for wire and cable: copper, aluminum, aluminiumand and stale-copper. The preferred wire gauge according to AWG wires and wires: 18-26. The thickness of the insulating material 37 is not greater than 25 mils, preferably less than 15 mils, and in some applications even less than 10 mils.

According to the present invention an insulated electrical connection element is made by extrusion of a foam composition around the wire, and the foaming and expansion of the composition. In the method of foaming can be used for chemical and/or mechanical pore-formers, such as nitrogen, which are typically used for the manufacture of foam insulation in the manufacture of wires and cables. The polymer composition contains not more than 20 wt.% polymer with ultra high SRA above 55%. The presence of a polymer of ultra-high the ER provides good foaming properties for insulation. The polymer composition preferably contains at least one additional polymer, which is selected because of its good electrical characteristics and/or environmental stability. Polymers suitable for use in the present invention, it is possible to choose from any number of commercially available polymers that are commonly used in the manufacture of wires and cables, including polyolefins such as polypropylene and polyethylene of low, medium and high density. For use as a component with ultra high SRA particularly preferred is a low-density polyethylene, preferably polyethylene having a density within the approximate values 0,915 - 0.930 g/scooter Optional component polymer is preferably polyethylene medium and/or high density. This additional polymer preferably has a high accelerated high temperature stability, determined by the time of the oxidative induction time of more than 15 minutes at 200aboutAccording to the method of 4568 by the ASTM.

The ability of the deformed polymer molecular chains to accumulate energy will affect the amount of swelling due to temperature and work. Such a polymer as a low density polyethylene (LDPE) with longer-chain and side branching will accumulate Bo is the more energy and recover at a higher rate after processing, than LDPE with similar molecular weight with shorter chains and with less lateral branching. The measurement of the recoverability may be determined by the degree of swelling of the extrudate (SRA) according to the following relationship

SRE (%)=[(ds-do)/do×100],

where ds- the outer diameter of the extruded material and do- inner diameter of the mouthpiece of the head plastometer extrusion according to ASTM D1238, dsand doyou can define in the measurement of the rate of melting (PP) plastometer extrusion. The diameter of the mouthpiece is measured at room temperature, usually before heating device. Get the diameter of the extrudate was measured after cooling to room temperature. The usual set of test conditions according to ASTM D1238 using a low-density polyethylene: temperature 190aboutWith the load of 2160 g

According to theory: the distribution of molecular weight (molecular weight/srednekislye molecular weight) also plays an important role in determining the properties of high SRA. During this study it was found that the compounds of LDPE with a molecular weight distribution that is equal to eight (8) or more, gave significantly higher SRA and elasticity of the melt, it is desirable for the formation of the foam dielectric isolation low the th density for elements of communication. Although these properties to a greater extent have based polymers LDPE manufactured by way of autoclave reactions, but these based polymers LDPE, get some tubular products, or other reactor products, can provide similar performance. The polydispersity or the value of electrosurgery (EA)determined according to the method of the company Equistar Chemicals, is also an indicator of the elasticity of the melt of polyethylene products. Methods of measuring the value of EA set forth in article R. Shroff, et al "New Measures of Polydispersity from Rheological Data on Polymer Melts", J. Applied Polymer Science, Vol. 57, pp. 1605-1626 (1995) and in U.S. patent 5534472; both sources are listed here as a reference. According to Table 1 materials with high CRE correlate with elevated values of EA and improved outcomes foaming.

Table 1

The results of SRA LDPE-components
MaterialSRE (%)Mol.-mass.

the distribution.
Predisp.

(the value of EO)
Foaming
LDPE No. 1517,1the 1.44Low
LDPE No. 2618,01,58Good
LDPE No. 376 9,92,34Excellent

During this experiment were made in the assessment list of primary polyethylene compounds (high density polyethylene) and secondary polyethylene compounds with high SRA for electrical parameters in relation to the scattering coefficient of electrical molded sample size of 75 mils (of 0.075 inch). This parameter is also called "loss tangent". Meter HP/Agilent Model 4342A Q was used to measure the dissipation factor and dielectric constant at a frequency of 1 MHz. Usually this measurement is expressed in microradian or value multiplied by 10-6radians.

Component of medium-density polyethylene (PESP) is designated as "clean", i.e. having a low or zero content of antioxidants, stabilizers against the action of light; additives improve slip or antibioticsa additives. Polymers based on PASP with a high content of stabilizers or additives will not match the electrical criteria or properties of aging under the influence of the temperature set for the properties of optimal damping. In this respect, component-based high-density polyethylene (HDPE) foam dielectric mixture contains, minimally, environmental stabilizers and antiochis the teli, need to ensure long-term accelerated high temperature stability and resistance to accelerated high temperature cracking under the stress of foams mixture of HDPE/PASP. It is important to note that although the stabilizers needed for the characteristics of durability, but the introduction of these stabilizers are usually adversely affects the electrical damping. For the desired environmental stabilization with optimal properties attenuation preferred system consists of such primary high-performance phenolic antioxidant as Irganox 1010 or 1076 (Ciba Chemicals), and such secondary Fofanova joint stabilizer as Irgafos 168 (Ciba Chemicals). The combination of primary and secondary antioxidants provides a synergy effect and affect long-term accelerated high temperature stability of the foam products. In addition, stabilizing the system preferably includes a third multi function long-term stabilizer families of space-obstructed amines which serve as light stabilizers for polymers (PSAS), providing additional long-term environmental stability and protection from exposure to light (ultraviolet radiation). On the basis of the levels required for effective UV stabilization, it was assumed that additional PSAS-n is the load will adversely affect the dissipation factor (so - attenuation) HDPE used in the manufacture of coaxial cables. In Table 2 the results of the tests show that the coefficients of the scattering compounds HDPE containing different mixtures of primary and secondary antioxidants and PSAS not match that predicted by theory.

A mixture of antioxidants and PSAS used in this particular implementation, is the following:

- phenolic antioxidant Irganox 1010 - 200 parts per million, is ideal;

- a mixture of phenolic antioxidant-phosphite - 400 parts per million, is ideal;

family spatially difficult amines serving as a light stabilizers: Chimassorb 944 or Tinuvin 622 - 400 parts per million;

- calcium stearate - 600 parts per million

There are such industrial mix as Irganox B215 (Ciba), which also provide the right balance of primary and secondary antioxidants. Of course, to describe the state of the material can also be used mixtures of similar components from other manufacturers in various other concentrations.

Table 2

Antioxidant systems and scattering coefficients
ComponentCoeff.

Russ.

(micro

rad.)
Molek.

weight
They say

-masses.

distribution.
The VOG,

minutes

when

200°
The notes.
HDPE

And
15795006,736 minDensity 0,963 (400 parts per million 1010 and 600 parts per million CaSt)
HDPE

In
12764005,117 minDensity 0,952 (400 parts per million 1076 and 600 parts per million

CaSt)
HDPE

19764005,122 minHDPE In combination with complex

stabilizers

AO/PSAS
HDPE

D
17795006,736 minHDPE In combination with complex

stabilizers

AO/PSAS
LDPE 1115950005,3< 251 SRA
LDPE 2411470008,0< 2 min61 SRA
LDPE 377180009,9< 2 min76 SRA

Resistance to accelerated high temperature cracking under tension foam coaxial element diameter 0,180 inches with a Central residential stale-copper was tested according to the accordance with the prescribed test method wraps foam core around the mandrel, the diameter of which is one times the diameter of the test element. This test sample is subjected to a voltage level which is proportional to its diameter. According Fig. 4 the length of the cable core with an inner conductor surrounded by a foam dielectric, formed into a loop and tightly wound around the standing part of the core wires of the cable. This prepared sample is then subjected to temperatures of 100aboutWith, and periodically monitor until then, until you see cracks - Fig. 5. The results of these tests showing the effect of (1) enable PASP with high CRE and (2) a combination of primary and secondary antioxidants together with PSAS presented in Table 3.

Table 3

Resistance to accelerated high temperature cracking under tension
Material

(from Table. 2)
Attitude

(Visp/

environments. pl.)
The actual

Density

(g/CC)
Resistance to accelerated high temperature cracking

Under voltage

% violations/

h)
HDPE - In and PASP 285/150,3280% 1344 h
HDPE - D and PASP 285/15of 0.332 0% 912 h
HDPE - and PASP 285/150,3400% 2472 h
HDPE and PASP 285/150,32390% < 48 hours
HDPE and PASP 170/300,36190% < 72 h
HDPE and PASP 170/300,360100% < 96 h
HDPE - In and PASP 385/150,3300% 1400 h

Figure 6 shows how the dissipation factor and the density of the insulation material effect on the attenuation. The top curve shows the attenuation depending on the frequency of isolation of the polymer composition with a dissipation factor of 40×10-6, expanded to two different densities (0,240 g/CC and 0.200 g/CC). The graphs for the two densities impose on each other. The second curve represents a polymer with a low dissipation factor of 22×10-6also foamed to the same two densities. It is seen that the reduced scattering coefficient provides a very significant reduction in attenuation at higher frequencies. While the graphics for the two densities appear superimposed on each other in this large-scale chart, but on an enlarged scale of this graph shows that the lower density has a lower cost is W. The present invention provides the ability to create high-quality, environmentally stable, low density structure of closed cells with low dissipation factor and the corresponding reduced attenuation.

These discoveries and their subsequent experimental implementation shows that the desired combination of high resistance to cracking under stress, low damping (dissipation factor and density), low cost (density) and stable, small and closed cell foam extrusion is possible to provide a stable, repeatable basis due to non-novel combinations of the above materials.

Because of the presents in the above description and associated drawings, the disclosure of the present invention to specialists in the art will be apparent that many modifications and other embodiments of the present invention. Therefore, it is implied that these inventions are not limited to the disclosed variants identified here realizations, and that these modifications and alternative implementations are included in the scope of the attached claims. Used here, the terms are only genus and descriptive sense, but not for purposes of limitation.

1. The electrical connection element, stereomirror and the surrounding foam insulation, containing not more than 20 wt.% polymer having ultra-high degree of extrudate swell of over 55%, and at least one additional polyolefin composition having high accelerated high temperature stability, determined by the time of oxidation induction (VOG) more than 15 min at 200°C.

2. Electric element according to claim 1, in which at least one additional polymer is time oxidative induction over 20 minutes

3. The electrical connection element according to claim 1, in which the insulation is resistant to accelerated high temperature cracking under the strain, 100 h at 100°in rolled into a spiral state, subjected to a voltage whose level is 1 times the outer diameter of the insulation without radial or longitudinal cracks.

4. The electrical connection element according to claim 1, in which the insulation contains a polymer with an ultra-high die swell of at least one additional polymer, the diffusion coefficient which is lower than that of polymer with high degree of dispersion and less than 75 microradian.

5. The electrical connection element according to claim 4, in which at least one additional polymer has a dissipation factor of less than 50 microradian.

6. The electrical connection element according to claim 1, in which the insulation contains a polymer of ultra-high is the degree of swelling of the extrudate and at least one additional polymer, high accelerated high temperature stability, determined by the time of oxidation induction (VOG) more than 15 min at 200°and also having a dissipation factor of less than 75 microradian.

7. The electrical connection element according to claim 6, in which at least one additional polymer is a polyolefin high degree of stabilization containing phenolic antioxidants and/or mixture of phenolic antioxidant phosphite as sitosterolemia families of space-obstructed amines.

8. The electrical connection element according to claim 1, in which the foam insulation contains about 15 wt.% olefin polymer having a degree of swelling of the extrudate over 55%.

9. The electric connection element of claim 1, wherein the composition of at least one additional polyolefin has a dissipation factor lower than that of low density polyethylene and less than 75 microradian.

10. Coaxial cable containing the core wires of the cable comprising a Central conductor and surrounding the dielectric, and an outer conductor surrounding the said core wires of the cable in which the core wires of the cable formed by the electrical connection element according to claim 1.

11. Twisted pair cables containing at least two twisted pairs of insulated electrical wires, in which each of the isolated e is krichesky wires formed electrical connection element according to claim 1.

12. Electric communication cable containing the wire and the surrounding foam insulation containing a mixture of a first olefin having ultra-high degree of extrudate swell of over 55% and is present in an amount of not more than 20 wt.%, and at least one additional polyolefin, having high environmental stability, determined by the time of oxidation induction (VOG) more than 15 min at 200°C.

13. Electrical connection cable section 12, in which at least one additional polyolefin has a dissipation factor lower than the above-mentioned polyolefin ultra-high degree of swelling, and less than 75 microradian.

14. Electrical connection cable 13, in which at least one additional polyolefin is a polyolefin high degree of stabilization containing phenolic antioxidants and/or mixture of phenolic antioxidant phosphite as sitosterolemia families of space-obstructed amines.

15. Electrical connection cable section 12, in which the mentioned mixture of the first olefin and said at least one additional olefin has time oxidative induction (VOG) more than 15 min at 200°C.

16. Electrical connection cable 15, in which the said mixture has time oxidative induction longer than 20 min or more.

17. E. ectricity connection cable 12, in which the communication cable has a resistance to accelerated high temperature cracking under tension over 100 hours at 100°in rolled into a spiral state, when the voltage level of 1 times greater than the outer diameter of insulation, without the appearance of radial or longitudinal cracks.

18. Electric communication cable containing the wire and the surrounding foam insulation containing a mixture of a first olefin having ultra-high degree of extrudate swell of over 55% and is present in an amount of not more than 20 wt.%, and having a high degree of stabilization of polyolefin containing phenolic antioxidants and/or mixture of phenolic antioxidant phosphite together with sitosterolemia families of space-obstructed amines.

19. Electrical connection cable p, in which the mixture has time oxidative induction (VOG) more than 15 min at 200°C.

20. Electrical connection cable p, in which the mixture has a dissipation factor of less than 75 microradian.

21. Electrical connection cable p, in which the communication cable has a resistance to accelerated high temperature cracking under tension over 100 hours at 100°in rolled into a spiral state when the voltage level, 1 times greater than the outer diameter of insulation, without the appearance of radial or longitudinal cracks.

22. Electric is Abel communication p, in which the polyolefin ultra-high degree of swelling of the extrudate is about 15 wt.% mentioned mixture.

23. Electrical connection cable item 22, in which the polyolefin ultra-high degree of swelling of the extrudate is low density polyethylene.



 

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23 cl, 6 dwg, 3 tbl

FIELD: process for manufacture of flat fiber-reinforced composite article which may be used as construction or packaging material.

SUBSTANCE: method involves placing fibers on lower substrate; applying liquid foam hardening binding agent onto fibers so as to completely coat fibers with binding agent; feeding fibers coated with binding agent and positioned between upper and lower substrates into space between upper and lower pressing plates continuously movable on upper side relative to lower side of fibers with binding agent, with fibers coated with binding agent moving at the velocity of pressing plates allowing binding agent to be foamed, expanded and hardened between upper and lower pressing plates; removing substrates from hardened article. Method further involves manufacturing cohesion fibrous mat from fibers. Before applying of binding agent onto mat, thickness of fibers makes from about 0.5 mm to about 0.8 mm, width - from 0.3 mm to 2 mm, and length of at least 80% of fibers makes at least 100 mm, moisture content of fibrous mat before application of binding agent is at least 5%. Method further involves applying binding agent onto mat so as to form mixture of binding agent and fibrous mat. Mixture contains fibers close to upper surface of mat, said surface facing upper pressing plates, and to lower surface of mat facing lower pressing plates. Mixture of mat fibers and binding agent is moved by means of upper and lower substrates between which said mixture is positioned. Before removal of substrates, mixture is exposed to pressure of from at least 0.8 bar but not in the excess of 5 bar to result in hardening of flat article having thickness of from about 10 mm to about 150 mm. Also described are apparatus for manufacture of flat fiber-reinforced composite article and flat fiber-reinforced composite rigid article.

EFFECT: minimized manufacture costs and improved quality of article having stable shape.

19 cl, 6 dwg

FIELD: manufacturing heat-insulated pipes.

SUBSTANCE: method comprises manufacturing pipe that is composed of one or several inner pipes, outer pipe that is mounted concentrically and with a spaced relation to the inner pipe, and insulation that is mounted within the space between the inner and outer pipes and is made on the basis of polyurethane or polyisocyanurate foams.

EFFECT: reduced cost and improved heat insulation.

5 cl, 2 dwg

FIELD: chemistry.

SUBSTANCE: foamed material consists of a single-component, moisture-curable composition containing at least one polymer P, having isocyanate groups and/or alkoxy silane groups, 10-60 vol. % of at least one gas and 10-30 wt % soot per total weight of the single-component foamed material which is curable in a moist medium. Application of the obtained foamed material is carried out primarily at temperature in the range of 10-40°C. The degree of foaming of the composition and, consequently, gas content of the single-component, moisture-curable foamed material varies during its application.

EFFECT: obtaining single-component, moisture-curable foamed material which can be used as an adhesive or a sealant/packing material for producing coatings or filling hollow structures with foamed material, particularly vehicles.

20 cl, 4 dwg, 1 ex

FIELD: process engineering.

SUBSTANCE: invention may be used for production of long sheet reinforced fluoroplastic billets for friction assembly operated without lubrication. Polydisposed polymer film is produced from fluoroplastic-4 or from compositions based thereon. Strip mesh power are filled by said film by rolling said film on both sides. Produced sheets are wound on rolls to be fitted in limiting mandrels with no clearance. Billets are sintered at 643-653 K and pressure developed by expansion of fluoroplastic-4 and cooled down thereafter. Billets are withdrawn from mandrels and passed through rolls.

EFFECT: simplified procedure, expanded range of products.

2 ex

FIELD: process engineering.

SUBSTANCE: invention relates to production of crimped heat-insulated pipeline. Pipeline comprises at least one inner pipe, crimped outer pipe spaced therefrom and made of synthetic material and a ply of foamed synthetic material to fill the spacing between both pipes. First, ply of foam is applied to inner pipe to extrude outer pipe thereat. After extrusion of outer pipe, forming tools are used to make crimps on foam ply.

EFFECT: higher flexibility of pipe.

15 cl, 3 dwg

FIELD: insulating materials for telecommunication cables.

SUBSTANCE: polyolefin insulation of conductors in hydrocarbon lubricant filled telecommunication cable which is then placed in junction box operating in the open is susceptible in particular to adverse impact of heat, oxygen, and moisture. In order to ensure reliable functioning of these conductors under mentioned conditions, use can be made of combination of one or more primary phenolic antioxidants chosen from N,N'-hexane-1.6-diilbis-(3(3.5-di-tertiary-butyl-4-hydroxyphenylpropionamide)), tris(3.5-di-tertiary-butyl-4-hydroxybenzyl)isocyanin-rhata, and tris(2-(3.5-di-tertiary-butyl-4-hydroxyhydrocinnamoyloxy)-ethyl)isocyanourate together wit one or more alkyl hydroxyphenyl alkanoylhydrazine metal deactivators.

EFFECT: enhanced oxidation resistance of polyolefin insulation of conductors.

8 cl, 1 tbl, 1 ex

FIELD: cable industry.

SUBSTANCE: proposed composition designed for insulating and sheathing cables and wires meant for operation under high fire hazard conditions incorporates following ingredients, parts by weight: suspension polyvinyl chloride, 100; ester plasticizer, 30 - 70; tribasic lead sulfate, 2 - 6; calcium carbonate, 20 - 300; zinc oxide, 0.5 - 10; aluminum oxide trihydrate, 20 - 70; antimony trioxide, 3 - 8; zinc borate, 0.5 - 8; zinc stearate, 0.25 - 4. Zinc borate and stearate introduced in definite proportion into proposed composition have made it possible to improve fire-safety characteristics of the latter.

EFFECT: reduced emission of smoke and hydrogen chloride in burning, enhanced degree of inflammability.

1 cl, 1 tbl

FIELD: electrical engineering.

SUBSTANCE: proposed polymeric insulating composition given in description of invention together with description of cables and wires covered with such composition to ensure their excellent performance in service has 60 to 90 mass percent of copolymer A of ethylene and α-olefin produced by copolymerization with aid of concentric catalyst and 40 to 10 mass percent of polyolefin resin B other than copolymer A and includes polyolefin incorporating grafted substituents with dipole moment 4 D or higher. One of alternative compositions uses semiconducting composition as semiconductor layer. In particular cases ethylene and α-olefin copolymer is produced by polymerization with aid of Ziegler-Natta catalyst.

EFFECT: facilitated production.

8 cl, 2 tbl

FIELD: cable industry.

SUBSTANCE: proposed composition designed for insulating general industrial cable and wire sheaths to reduce fire occurrences due to inflammation of cables and wires has following ingredients, mass percent: polyvinyl chloride suspension, 100; ester plasticizer, 25 - 75; lead stabilizer, 1 - 7; calcium stearate, 0.7 - 3; diphenylolpropane, 0.1 - 0.8; zinc oxide, 0.5 - 8; zinc borate, 0.5 - 5; calcium chloride, 0.1 - 2 or calcium oxide, 0.1 - 2; calcium carbonate, 5 - 90; antimony trioxide, 0.5 - 9; and carbon black, 1 - 8.

EFFECT: reduced inflammability and smoke-forming capacity due to introduction of zinc oxide, zinc borate, and calcium chloride or calcium oxide.

3 cl, 1 tbl

FIELD: cable industry.

SUBSTANCE: proposed composition designed for insulating sheaths of cables and wires operating under high fire hazard conditions has following proportion of ingredients, part by mass: suspension polyvinyl chloride, 100; ester plasticizer, 35 - 65; lead stabilizer, 2 - 7; calcium carbonate, 5 - 45; aluminum oxide trihydrate, 20 - 100; antimony trioxide, 5 - 9; zinc oxide, 0.5 - 8; and newly introduced zinc borate, 0.5 - 8; calcium stearate, 1 - 3; calcium chloride, 0.1 - 2 or calcium oxide, 0.1 - 2.

EFFECT: enhanced fire resistance at low degree of smoke emission under fire conditions.

1 cl, 1 tbl

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