Elongated article with good flexibility and high flame retardancy

Abstract

The invention relates to elongated articles and polymer compositions used for preparing the elongated articles. The elongated articles comprise an inner structure/one or more elements including a static/moving current medium or communication medium; and a halogen-free polymer composition surrounding the element(s). The polymer composition includes a linear very low density polyethylene (VLDPE) composition and one or more polyolefin-elastomers. In addition, the polymer composition includes a flame retardant filler.

Claims

1. An Elongated article comprising: (i) one or more elements including a medium with static/moving charge/current or communication medium; and (ii) a halogen-free polymer composition surrounding the element(s), wherein said polymer composition is obtainable or obtained by compounding and extrusion of at least the following components: (a) 24-26.5 wt.-% of a linear very low density polyethylene (VLDPE) composition having a density in the range from 0.85 g/cm.sup.3 to 0.93 g/cm.sup.3, and having a melting point of above 110 C., wherein the linear very low density polyethylene composition comprises a mixture of two different types of linear very low density polyethylene compositions, which is a mixture of 18-23 wt.-% of a first composition being a homopolymer, having a density in the range from 0.85 g/cm.sup.3 to 0.95 g/cm.sup.3, as measured according to ISO 1183 and a melt flow index of 8-15, as measured according to ASTM 1238, and 2.0-6.5 wt.-% of a second composition, having a density in the range from 0.85 g/cm.sup.3 to 0.95 g/cm.sup.3, as measured according to ISO 1183 and a melt flow index of 2-5, as measured according to ASTM 1238; (b) 9.5-13 wt.-% of one or more polyolefin-elastomers, wherein the polyolefin-elastomer(s) is/are (an) ultra-low density random ethylene-octene copolymer(s) having a glass transition temperature of below 50 C.; and (c) 61-66 wt.-% of flame retardant filler, which is a hydrated metal-based filler.

2. The elongated article according to claim 1, wherein the polymer composition further comprises: (a) 0.1-3.0 wt.-% of an antioxidant; and (b) 0.5-2.5 wt.-% of a coupling agent composition.

3. The elongated article according to claim 1, wherein the polymer composition has an elongation at break in the range from 200% to 350%, as measured by IEC 60811-501, measured by using the elongated article without the one or more elements.

4. The elongated article according to claim 1, wherein the linear very low density polyethylene composition comprises a mixture of two different types of linear very low density polyethylene compositions.

5. The elongated article according to claim 1, wherein the polyolefin-elastomer has a density in the range from 0.80 g/cm.sup.3 to 0.90 g/cm.sup.3, as measured according to ASTM D792.

6. The elongated article according to claim 1, wherein the polyolefin-elastomer has a value of ShoreD hardness of less than 20, as measured by ASTM D2240.

7. The elongated article according to claim 1, wherein the flame retardant filler is fine precipitated hydrated metal-based filler.

8. The elongated article according to claim 1 comprising from 1 to 3 elements and the elongated article has an outer diameter of less than 6.2 mm.

9. The elongated article according to claim 1, wherein the polymer composition does not contain a high density polyethylene homopolymer having a density of 0.94 g/cm.sup.3 or higher.

10. The elongated article according to claim 1, wherein, the glass transition temperature of the polyolefin-elastomer/ ultra-low density random ethylene-octene copolymer is 58 C.

11. The elongated article according to claim 1, wherein the density of the polyolefin-elastomer/ ultra-low density random ethylene-octene copolymer is in the range from 0.80 g/cm.sup.3 to 0.90 g/cm.sup.3, as measured according to ISO 1183.

12. The elongated article according to claim 1, wherein the linear very low density polyethylene (VLDPE) composition has a melting point above 110 C.

13. The elongated article according to claim 1, which passes the alternate bending test (EN 50396) with 30,000 cycles.

14. The elongated article according to claim 1, wherein the polymer composition does not contain a plasticizer.

15. The elongated article according to claim 1, wherein the polymer composition does not contain a polysiloxane.

16. The elongated article according to claim 1, wherein the polymer composition is not UV crosslinked.

17. The elongated article according to claim 1, wherein the polymer composition has a strength at break in the range from 5.5 MPa to 12.0 MPa, as measured by IEC 60811-501.

Description

DETAILED DESCRIPTION

(1) The invention relates to the following items:

(2) 1. Elongated article comprising:

(3) (i) one or more elements including a medium with static/moving charge/current (or electric charge) or communication medium; and

(4) (ii) a halogen-free polymer composition surrounding the element(s), wherein said polymer composition is obtainable or obtained by compounding and extrusion of at least the following components onto component (i), i.e. the one or more elements:

(5) (a) 24.0-27.0 wt.-% of a linear very low density polyethylene (VLDPE) composition having a density in the range from 0.85 g/cm.sup.3 to 0.93 g/cm.sup.3, as measured according to ISO 1183, and having a melting point of above 110 C., e.g., determined by differential scanning calorimetry (DSC) measurement;

(6) (b) 8.0-15.0 wt.-% of one or more polyolefin-elastomers, wherein the polyolefin-elastomer(s) is/are (an) ultra-low density random ethylene-octene copolymer(s) having a glass transition temperature of below 50 C. as determined in the polymer composition or in pure form, wherein the determination of the melting point will be provided, e.g., from the DSC measurement, and/or a melting point of below 40 C. as determined in the polymer composition or in pure form, wherein the determination of the melting point will be provided on basis of e.g., the DSC measurement, wherein, by way of example, Engage 8842 of Dow has a very low melting point of 38 C.; and

(7) (c) 61-66 wt.-% of flame retardant filler, which is a mineral hydroxide/hydrated metal-based filler.

(8) 2. The elongated article according to item 1, wherein the polymer composition further comprises: (d) 0.1-3.0 wt.-% of an antioxidant; and (e) 0.5-2.5 wt.-% of a coupling agent composition.

(9) 3. The elongated article according to item 1 or 2, wherein the polymer composition has (aa) an elongation at break in the range from 200% to 400%, preferably 300% to 400%, as measured by IEC 60811-501, preferably measured by using the elongated article without the one or more elements, and/or

(10) (bb) a strength at break in the range from 7.5 MPa to 12.0 MPa, or 8.0 MPa to 10.0 MPa, preferably 9.0 MPa to 10.0 MPa, preferably before ageing, as measured by IEC 60811-501 and as required by DIN EN 50363-8. During ageing, the samples are placed into an oven for 7 days at 80 C., then put into a desiccator and then tested. The deviation in elongation and tensile strength is preferably not bigger than 20%. Unless otherwise stated, all values referred to herein are measured without ageing.

(11) 4. The elongated article according to any preceding item, wherein the linear very low density polyethylene composition is/comprises a mixture of two different types of linear very low density polyethylene compositions, preferably a mixture of 18-23 wt.-% of a first composition, preferably having a density in the range from 0.85 g/cm.sup.3 to 0.95 g/cm.sup.3, preferably of about 0.9 g/cm.sup.3, as measured according to ISO 1183, and 2.0-6.5 wt.-% of a second composition, preferably having a density in the range from 0.85 g/cm.sup.3 to 0.95 g/cm.sup.3, preferably of about 0.9 g/cm.sup.3, as measured according to ISO 1183. Preferably, the VLDPE, which is present in a higher amount, has a higher melt flow rate compared with the other VLDPE. Preferably, the VLDPE being present in an amount of 2.0-6.5 wt.-% has a melt flow index of 2-5, as measured according to ASTM1238 (190 C./2.16 kg; g/10 min), while the VLDPE being present in an amount of 18-23 wt.-% has a melt flow index of 8-15, as measured according to ASTM1238 (190 C./2.16 kg; g/10).

(12) 5. The elongated article according to any preceding item, wherein the linear very low density polyethylene composition has a density in the range from 0.85 g/cm.sup.3 to 0.92 g/cm.sup.3, preferably in the range from 0.85 g/cm.sup.3 to 0.90 g/cm.sup.3, as measured according to ISO1183.

(13) 6. The elongated article according to any preceding item, wherein the polyolefin-elastomer has a density in the range from 0.80 g/cm.sup.3 to 0.90 g/cm.sup.3, preferably of about 0.859 g/cm.sup.3, as measured according to ASTM D792.

(14) 7. The elongated article according to any preceding item, wherein the polyolefin-elastomer (composition) has an elongation at break of at least 1000%, further preferred at least 1100%, most preferably about 1200%, as measured by ASTMD638.

(15) 8. The elongated article according to any preceding item, wherein the polyolefin-elastomer has a value of ShoreD hardness of less than 20, as measured by ASTM D2240 (compression molded sample, wherein a sample of the polyolefin-elastomer is molded into a plate). The value of ShoreD hardness of the elongated article/polymer composition preferably is 32-38.

(16) 9. The elongated article according to any preceding item, wherein the polymer composition is applied by hot-melt extrusion at a temperature in the range from 100 C. to 175 C., preferably 100-170 C.

(17) 10. The elongated article according to any preceding item, wherein the flame retardant filler is fine precipitated hydrated metal-based filler, e.g., aluminum hydroxide or magnesium hydroxide, preferably having about 99.4% purity. One example of such filler is Martinal OL-104 LEO.

(18) 11. The elongated article according to any preceding item, wherein the coupling agent composition is a mixture of vinyltriethoxysilane and 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane.

(19) 12. The elongated article according to any preceding item, wherein the antioxidant is a phenolic antioxidant, preferably tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] methane.

(20) 13. The elongated article according to any preceding item comprising from 1 to 8 elements, each having diameters of up to 4.0 mm, such as diameters from 0.5 to 4.0 mm, and preferably having from 2 to 5 elements. The static/moving current media or communication media of the elements can be a metal wire, wherein the wire can be one piece of metal, preferably the wire is further stranded. The wire can be surrounded by a polymer layer to form the element.

(21) 14. The elongated article according to any preceding item, wherein the polymer composition does not contain a plasticizer.

(22) 15. The elongated article according to any preceding item, wherein the polymer composition does not contain a high density polyethylene homopolymer having a density of 0.94 g/cm.sup.3 or higher, preferably not containing a high density polyethylene homopolymer having a density of 0.92 g/cm.sup.3 or higher.

(23) 16. The elongated article according to any preceding item, wherein the polymer composition does not contain a polysiloxane.

(24) 17. The elongated article according to any preceding item, wherein the polymer composition surrounds the elements to provide a sheath for mechanical protection of the elements.

(25) 18. The elongated article according to any preceding item, wherein, the glass transition temperature of the polyolefin-elastomer/ultra-low density random ethylene-octene copolymer is 58 C.

(26) 19. The elongated article according to any preceding item, wherein the polymer composition is not UV crosslinked.

(27) 20. The elongated article according to any preceding item, having an MFI of at least 9 g/10 min, preferably 10-12 g/10 min, further preferred about 11 g/10 min, as measured according to EN ISO 1133 under the conditions at 150 C. and the load of 21.6 kg.

(28) 21. The elongated article according to any preceding item, wherein the density of the polyolefin-elastomer/ultra-low density random ethylene-octene copolymer is in the range from 0.80 g/cm.sup.3 to 0.90 g/cm.sup.3, as measured according to ISO 1183.

(29) 22. The elongated article according to any preceding item, wherein the polymer composition has a value of ShoreD hardness of 32-38, preferably 35-37, further preferred about 36.

(30) 23. The elongated article according to any preceding item, wherein the linear very low density polyethylene (VLDPE) composition having a melting point above 110 C., preferably has a melting point which is below 120 C. measured and/or determined by the method of DSC measurement.

(31) 24. The elongated article according to any preceding item, wherein the linear very low density polyethylene (VLDPE) composition has a Vicat temperature (Vicat softening temperature) of above 50 C., for example, measured according to the ASTM D1525 method.

(32) 25. The elongated article according to any preceding item, which passes the alternate bending test (EN 50396).

(33) 26. Polymer composition obtainable or obtained by compounding at least the components (a)-(c), preferably also components (d) and (e) as described herein.

(34) 27. Elongated article, in particular elongated article of any of items 1-25, comprising:

(35) (i) an inner structure, preferably comprising one or more elements as described herein, preferably as defined in any of items 1, 13, and 17; and

(36) (ii) a polymer composition surrounding the inner structure, wherein the polymer composition comprises a mixture of a linear very low density polyethylene (VLDPE) composition, a polyolefin-elastomer, which is an ultra-low density random ethylene-octene copolymer, a mineral hydroxide/hydrated metal-based filler flame retardant filler, an antioxidant and a coupling agent composition; and wherein the polymer composition has

(37) (aa) an elongation at break in the range from 150% to 500%, or 300% to 400%, preferably >340%, such as >340% to 400%, as measured by IEC 60811-501; and/or

(38) (bb) a strength at break in the range from 7.5 MPa to 15.0 MPa, or 8.0 MPa to 12.0 MPa, preferably 9.0 MPa to 10.0 MPa, as measured by IEC 60811-501, preferably before ageing.

(39) 28. The elongated article according to item 27, or elongated article of any of items 1-27, wherein the linear very low density polyethylene (VLDPE) composition is contained in an amount of 24.0-26.5 wt.-%, and has a density in the range from 0.86 g/cm.sup.3 to 0.93 g/cm.sup.3, as measured according to ISO 1183, and having a melting point of above 110 C., e.g., measured by the differential scanning calorimetry (DSC).

(40) 29. The elongated article according to item 27 or 28, or elongated article of any of items 1-25, wherein the polyolefin-elastomer consists of one or more polyolefin-elastomers which are contained in an amount of 9.5-13.0 wt.-%.

(41) 30. The elongated article according to item 29, or elongated article of any of items 1-29, wherein the polyolefin-elastomer(s) is/are (an) ultra-low density random ethylene-octene copolymer(s) having a glass transition temperature of below 50 C. as determined in the polymer composition or in pure form, wherein the melting point is, e.g., determined by DSC measurement, and/or having a melting point of below 40 C. as determined in the polymer composition or in pure form, wherein the melting point is, e.g., determined by DSC measurement, wherein, by way of example, Engage 8842 of Dow has a very low melting point of 38 C.

(42) 31. The elongated article according to any preceding item, or elongated article of any of items 1-30, wherein the flame retardant filler is present in an amount of 61-66 wt.-%.

(43) 32. The elongated article according to any preceding item, or elongated article of any of items 1-31, wherein the polymer composition further comprises: 0.1-3.0 wt.-% of an antioxidant; and 0.5-2.5 wt.-% of a coupling agent composition.

(44) 33. The elongated article according to any preceding item, or elongated article of any of items 1-32, wherein the polymer composition has

(45) (aa) an elongation at break in the range from 300% to 500%, preferably >340% to 450%, or 350% to 400%, as measured by IEC 60811-501, preferably measured by using the elongated article without the inner structure, and/or

(46) (bb) a strength at break in the range from 8 MPa to 15 MPa, preferably before ageing, as measured by IEC 60811-501 and as required by DIN EN 50363-8, preferably measured by using the elongated article without the inner structure.

(47) 34. The elongated article according to any preceding item, or elongated article of any of items 1-33, wherein the linear very low density polyethylene composition comprises a mixture of two different types of linear very low density polyethylene compositions, preferably a mixture of 18-23 wt.-% of a first composition, preferably having a density in the range from 0.85 g/cm.sup.3 to 0.95 g/cm.sup.3, preferably of about 0.9 g/cm.sup.3, as measured according to ISO 1183, and 2.0-6.5 wt.-% of a second composition, preferably having a density in the range from 0.85 g/cm.sup.3 to 0.95 g/cm.sup.3, preferably of about 0.9 g/cm.sup.3, as measured according to ISO 1183. Preferably, the VLDPE, which is present in a higher amount, has a higher melt flow rate compared with the other VLDPE. Preferably, the VLDPE being present in an amount of 2.0-6.5 wt.-% has a melt flow index of 2-5 as determined according to ASTM1238 (190 C./2.16 kg; g/10 min), while the VLDPE being present in an amount of 18-23 wt.-% has a melt flow index of 8-15 as determined according to ASTM1238 (190 C./2.16 kg; g/10).

(48) 35. The elongated article according to any preceding item, or elongated article of any of items 1-34, wherein the linear very low density polyethylene composition has a density in the range from 0.85 g/cm.sup.3 to 0.92 g/cm.sup.3, preferably in the range from 0.85 g/cm.sup.3 to 0.90 g/cm.sup.3, as measured according to ISO1183.

(49) 36. The elongated article according to any preceding item, or elongated article of any of items 1-35, wherein the polyolefin-elastomer has a density in the range from 0.80 g/cm.sup.3 to 0.90 g/cm.sup.3, preferably of about 0.859 g/cm.sup.3, as measured according to ASTM D792.

(50) 37. The elongated article according to any preceding item, or elongated article of any of items 1-37, wherein the polyolefin-elastomer (composition) has an elongation at break, preferably measured by using the elongated article without the inner structure, of at least 1000%, further preferred at least 1100%, most preferably about 1200%, as measured by ASTM D638.

(51) 38. The elongated article according to any preceding item, or elongated article of any of items 1-37, wherein the polyolefin-elastomer has a value of ShoreD hardness of less than 20, as measured by ASTM D2240 (compression molded sample, wherein a sample of the polyolefin-elastomer is molded into a plate). The value of ShoreD hardness of the elongated article/polymer composition preferably is 32-38.

(52) 39. The elongated article according to any preceding item, or elongated article of any of items 1-38, wherein the polymer composition is applied by hot-melt extrusion at a temperature in the range from 100 C. to 175 C., preferably 100-170 C.

(53) 40. The elongated article according to any preceding item, or elongated article of any of items 1-39, wherein the flame retardant filler is fine precipitated hydrated metal-based filler, e.g., aluminum hydroxide or magnesium hydroxide, preferably having about 99.4% purity. One example of such filler is Martinal OL-104 LEO.

(54) 41. The elongated article according to any preceding item, or elongated article of any of items 1-40, wherein the coupling agent composition is a mixture of vinyltriethoxysilane and 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane.

(55) 42. The elongated article according to any preceding item, or elongated article of any of items 1-41, wherein the antioxidant is a phenolic antioxidant, preferably tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxphenyl)propionate] methane.

(56) 43. The elongated article according to any preceding item, or elongated article of any of items 1-42, wherein the inner structure comprises from 1 to 8 elements, each having diameters of up to 4.0 mm, such as diameters from 0.5 to 4.0 mm, and preferably having from 2 to 5 elements.

(57) 44. The elongated article according to any preceding item, or elongated article of any of items 1-43, wherein the polymer composition does not contain a plasticizer.

(58) 45. The elongated article according to any preceding item, or elongated article of any of items 1-44, wherein the polymer composition does not contain a high density polyethylene homopolymer having a density of 0.94 g/cm.sup.3 or higher, preferably not containing a high density polyethylene homopolymer having a density of 0.92 g/cm.sup.3 or higher.

(59) 46. The elongated article according to any preceding item, or elongated article of any of items 1-45, wherein the polymer composition does not contain a polysiloxane.

(60) 47. The elongated article according to any preceding item, or elongated article of any of items 1-46, wherein the polymer composition surrounds the inner structure to provide a sheath for mechanical protection of the inner structure.

(61) 48. The elongated article according to any preceding item, or elongated article of any of items 1-47, wherein, the glass transition temperature of the polyolefin-elastomer/ultra-low density random ethylene-octene copolymer is 58 C.

(62) 49. The elongated article according to any preceding item, or elongated article of any of items 1-48, wherein the polymer composition is not UV crosslinked.

(63) 50. The elongated article according to any preceding item, or elongated article of any of items 1-49, having an MFI of at least 9 g/10 min, preferably 10-12 g/10 min, further preferred about 11 g/10 min, as measured according to EN ISO 1133 under the conditions at 150 C. and the load of 21.6 kg.

(64) 51. The elongated article according to any preceding item, or elongated article of any of items 1-50, wherein the density of the polyolefin-elastomer/ultra-low density random ethylene-octene copolymer is in the range from 0.80 g/cm.sup.3 to 0.90 g/cm.sup.3, as measured according to ISO 1183.

(65) 52. The elongated article according to any preceding item, or elongated article of any of items 1-51, wherein the polymer composition has a value of ShoreD hardness of 32-38.

(66) 53. The elongated article according to any preceding item or elongated article of any of items 1-52, wherein the linear very low density polyethylene (VLDPE) composition having a melting point above 110 C., preferably has a melting point which is below 120 C. measured and/or determined by the method of DSC measurement.

(67) 54. The elongated article according to any preceding item, or elongated article of any of items 1-53, wherein the linear very low density polyethylene (VLDPE) composition has a Vicat temperature (Vicat softening temperature) of above 50 C., for example, measured to according to the ASTM D1525 method.

(68) 55. The elongated article according to any preceding item, or elongated article of any of items 1-54, which passes the alternate bending test (EN 50396).

(69) 56. Polymer composition obtainable or obtained by compounding of at least the components as defined in item 27 (ii).

(70) In the context of the present invention, the elongated article can be an elongated device for conjunction and/or connection of two devices for transferring electrical charges and/or information such as for power transmission or telecommunications. For example, the elongated article can be a cable. In such an elongated article, the inner structure/elements (which are surrounded by the polymer composition) can each include an electric conductor as the static/moving current medium or communication medium. The electric conductor is optionally itself surrounded by a shielding or sheathing, in particular a polymer composition/coating, thereby forming the element. The electrical conductor can be a wire, preferably comprising or consisting of one or more, e.g., 52, metal strands (e.g., copper strands), wherein the wire is optionally itself surrounded by a shielding or sheathing, thereby forming the element. The cable can, e.g., be used as low voltage cable such as for use in vacuum cleaner applications.

(71) In the context of the present invention, the weight percentages indicated for the components of the polymer composition are indicated as weight percentages based on the total weight of the polymer composition.

(72) Linear very low density polyethylenes (VLDPEs) as used herein are homopolymers.

(73) In the context of the present invention, the linear very low density polyethylene (VLDPE), ultra-low density random ethylene-octene copolymer (polyolefin-elastomer) and any other polymer component can be used in the form of commercially available products. Since these products may contain minor amounts of additives (e.g., antioxidants), in addition to, e.g., pure polyethylene or ethylene-octene copolymer, the aforementioned terms, e.g., linear very low density polyethylene (VLDPE), and ultra-low density random ethylene-octene copolymer (polyolefin-elastomer), encompass compositions comprising such minor amounts of additives, e.g., amounts of additives of below 1.0 wt.-% or below 0.5 wt.-%. It can reasonably be expected that such minor amounts of additives do not have a significant impact on the final properties of the polymer composition.

(74) In the context of the present invention, the parameters defined herein, in particular in the claims, can either be determined by testing the elongated article, the polymer composition, or the single/pure components of the polymer composition. A person skilled in the art can determine the most feasible approach. For example, if the density of a VLDPE, which is present in the polymer composition of an elongated article, is not known, the VLDPE may be extracted from the polymer composition and analyzed. If the glass transition temperature or melting point of a polyolefin-elastomer, which is present in the polymer composition of an elongated article, is unknown, these parameters can be determined via DSC methods on the polymer composition.

(75) As disclosed above, the invention relates to an elongated article comprising or consisting of (i) and (ii). The elongated article can be configured and can be used for connecting two devices for exchange of charges/information between the devices.

(76) Component (i) is one or more elements including a static/moving charge medium or communication medium. The one or more elements represent an inner structure. The elements/inner structure can have an elongated form with two ends in order to, e.g., each have a length of up to several kilometers. The elongated elements are aligned and are surrounded by component (ii). Furthermore, the static/moving current medium or communication medium of each of the elements can itself be surrounded by a coat, e.g., polymer coat/composition, which provides a shielding or sheathing. The one or more optionally surrounded static/moving current media or communication media together form component (i), i.e. the inner structure. Component (ii) mechanically protects component (i). During use of the elongated article, components (i) and (ii) may be subjected to many bending movements and pull force. As explained above, the elongated articles disclosed herein may have sufficient flexibility to avoid breaking thereof even after a very long period of use (determined by the alternate bending test).

(77) Component (ii) is a halogen-free polymer composition/component surrounding the elements/inner structure, i.e., component (i). It is not excluded, but less preferred, that there are additional coatings which either surround component (ii) or which are between components (i) and (ii).

(78) The polymer composition is obtainable or obtained by compounding, preferably HFFR compounding, of at least the components defined in component (ii) above.

(79) The linear very low density polyethylene (VLDPE) composition can contain one or more types of a very low density polyethylene, and is preferably present in an amount of 24.0-26.5 wt.-%, further preferred 22.5-25.5 wt.-%. It may have a density in the range from 0.86 g/cm.sup.3 to 0.93 g/cm.sup.3, as measured according to ISO 1183, and may have a melting point of above 110 C. as determined by differential scanning calorimetry. Such commercially available polyethylenes are, e.g., Clearflex MQF0 of Versalis and Clearflex CLDO of Polimeri Europa. One embodiment is 19.5-21.8% of a first linear very low density polyethylene composition, 3-5% of a second linear very low density polyethylene composition and 9.5-12.0% of one polyolefin-elastomer with, e.g., 62.5-64.5%, e.g., 62.5%, 63%, 63.5 or 64.0% flame retardant filler, e.g., hydrated metal-based filler/aluminum hydroxide, and optional components as defined herein adding up to 100%. A further embodiment is 19.5-21.8% Clearflex MQF0, 3-5% Clearflex CLDO and 9.5-12.0% Engage 8842 with, e.g., 62.5-64.5%, e.g., 62.5%, 63.0%, 63.5 or 64.0% flame retardant filler, e.g., hydrated metal-based filler/aluminum hydroxide, and optional components as defined herein adding up to 100%.

(80) The linear very low density polyethylene (VLDPE) composition having a melting point above 110 C., e.g., related to the differential scanning calorimetry (DSC) measurement, preferably has a melting point which is below 120 C. as, e.g., also determined by differential scanning calorimetry (DSC).

(81) The linear very low density polyethylene (VLDPE) composition can have a Vicat temperature (Vicat softening temperature) of above 50 C. for example, measured according to the ASTM D1525 method.

(82) The polyolefin-elastomer can comprise one or more different types of polyolefin-elastomers. The polyolefin-elastomer is preferably present in an amount of 9.5-13.0 wt.-%, further preferred 10.0-12.5 wt.-%, or 10.0-11.5 wt.-%. The one or more polyolefin elastomers are ultra-low density random ethylene-octane copolymers having a glass transition temperature of below 50 C. as determined by differential scanning calorimetry, and a melting point of below 60 C. or below 50 C., preferably below 40 C., as determined by differential scanning calorimetry. Such commercially available polyolefin-elastomers are Engage 8842, Engage 8180, Engage 8130, and Engage 8150 of Dow.

(83) The flame retardant filler is preferably present in an amount of 56-65 wt.-% and is a mineral hydroxide/hydrated mineral. Preferably, the polymer composition does not contain further polyethylene components and/or further polyolefin-elastomers.

(84) Compounding of the polymer composition can be performed by mixing the components in a molten state, e.g. in an Intermixer. A device which can suitably be used for extrusion in this context is an extruder, e.g., a twin screw extruder, single screw kneading extruder.

(85) The flame retardant filler or fillers used in the present invention are halogen free. According to the present invention, mineral hydroxides, i.e., mineral fillers which are hydrated oxides can be used. For example, aluminum or magnesium hydroxides, can be used. When exposed to high temperatures, the mineral fillers decompose through endothermic reaction and release large quantities of water, so as to stop the flame propagation. The flame retardant filler preferably is aluminum hydroxide, preferably fine precipitated aluminum hydroxide of about 99.4% purity. One example of such filler is Martinal OL-104 LEO of Albemarle.

(86) Preferably, the flame retardant filler is used in an amount of 58-65 wt.-%, or 60-65 wt.-%. In one embodiment, a combination of Clearflex MQF0, Clearflex CLDO and Engage 8842 is used. In one embodiment, a combination of Clearflex CLDO and Flexomer DFDA-1137 NT 7 is used.

(87) The polymer composition can further comprise 0.1-3.0 wt.-% of an antioxidant; and 0.5-2.5 wt.-% of a coupling agent composition.

(88) The polymer composition preferably has

(89) (aa) an elongation at break in the range from 150% to 500%, or 200% to 400%, preferably from 300% to 500%, preferably 350% to 450%, or 340% to 400%, as measured by IEC 60811-501, preferably before ageing and preferably by using the elongated article without the inner structure, in particular an elongated article in the form of a hollow cable with conductors removed according to EN 50363-8, and/or,

(90) (bb) a strength at break in the range from 7.5 MPa to 15.0 MPa, or 5.5 MPa to 12.0 MPa, preferably 8.0 MPa to 10.0 MPa, further preferred 9.0 MPa to 10.0 MPa, as measured by IEC 60811-501. During ageing, the samples are placed into an oven for 7 days at 80 C., then put into a desiccator and then tested. The deviation in elongation and tensile strength is preferably not bigger than 20%. Unless otherwise stated, all values referred to herein are measured without ageing.

(91) The linear very low density polyethylene composition can comprise a mixture of two different types of linear very low density polyethylene compositions, preferably a mixture of 18-23 wt.-% of a first composition having a density in the range from 0.85 g/cm.sup.3 to 0.95 g/cm.sup.3, preferably of about 0.90 g/cm.sup.3, as measured according to ISO 1183, and 2.0-6.5 wt.-% of a second composition having a density in the range from 0.85 g/cm.sup.3 to 0.95 g/cm.sup.3, preferably of about 0.90 g/cm.sup.3, as measured according to ISO 1183.

(92) The linear very low density polyethylene composition can have a density in the range from 0.85 g/cm.sup.3 to 0.92 g/cm.sup.3, preferably in the range from 0.85 g/cm.sup.3 to 0.90 g/cm.sup.3, as measured according to ISO 1183.

(93) The polyolefin-elastomer can have a density in the range from 0.80 g/cm.sup.3 to 0.90 g/cm.sup.3, preferably of about 0.86 g/cm.sup.3, as measured according to ASTM D792.

(94) The polyolefin-elastomer composition used for preparing the polymer composition (ii) can have an elongation at break of at least 1000%, further preferred at least 1100%, most preferably about 1200%, as measured by ASTMD638.

(95) The polyolefin-elastomer can have a value of ShoreD hardness of less than 20, as measured by ASTM D2240 (compression molded sample).

(96) The polymer composition can be applied by hot-melt extrusion at a temperature in the range from 100 C. up to 175 C., in a preferred embodiment of the invention in a range from 100 C. to 170 C.

(97) The coupling agent composition can be a mixture of vinyltriethoxysilane (Dynasilan VTEO of Evonik) and 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane (Trigonox 29-050 of AkzoNobel).

(98) The antioxidant can be a phenolic antioxidant, preferably tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] methane (e.g., Irganox 1010 of BASF).

(99) The inner structure of the elongated article and component (i) of the elongated article, respectively, can comprise from, e.g., 1 to 8 elements, each preferably having a diameter of up to 4.0 mm, such as diameters from 0.5 to 4.0 mm, and preferably having from 2 to 5 elements. Preferably, the elements are elongated and/or stranded. The static/moving current medium or communication medium of the elongated elements is preferably surrounded by a polymer composition. The static/moving current media or communication media can be wires, such as copper wires, and can optionally be surrounded by an insulation/polymer composition. The cross-section of each element without insulation, i.e. the cross-section of each of the static/moving current medium or communication medium, can for example be from 0.5 to 4.0 mm.sup.2. The elements, comprising the static/moving current medium or communication medium which are surrounded by a polymer composition, are brought in contact with and the polymer composition (ii) is then applied to the elements in an extrusion process. Preferably, the outer diameter of the elongated article is less than 6.2 mm. Preferably, the elongated article has a diameter so that it can include 2 elements, each comprising a static/moving current medium or communication medium, e.g. an electrical conductor, which is surrounded by a polymer composition and each having a cross-section, including the polymer composition, of 0.75 mm.sup.2 or less, wherein the diameter of all 2 elements together is about 6 mm. In one embodiment, the polymer composition does not contain a plasticizer.

(100) In one embodiment, the polymer composition does not contain a plasticizer.

(101) The polymer composition preferably does not contain a high density polyethylene homopolymer having a density of 0.94 g/cm.sup.3 or higher, preferably not containing a high density polyethylene homopolymer having a density of 0.92 g/cm.sup.3 or higher.

(102) The polymer composition preferably does not contain a polysiloxane. The polymer composition preferably does not contain a maleic anhydride grafted polymer.

(103) The polymer composition surrounds the inner structure to provide insulation for mechanical protection of the inner structure as well as protection of people from contact with electrical current. The polymer composition surrounding the inner structure is preferably provided in the form of a sheath. For example, the polymer composition coating the inner structure has a tubular shape.

(104) The glass transition temperature of the polyolefin-elastomer/ultra-low density random ethylene-octene copolymer preferably is 58 C. In one embodiment, the density of the polyolefin-elastomer/ultra-low density random ethylene-octene copolymer is in the range from 0.80 g/cm.sup.3 to 0.90 g/cm.sup.3, as measured according to ISO 1183.

(105) The polymer composition is preferably not UV crosslinked.

(106) In one embodiment, the elongated article has an MFI of at least 9 g/10 min, as measured according to EN ISO 1133 under the conditions at 150 C. and the load of 21.6 kg.

(107) The invention also refers to a polymer composition obtainable or obtained by compounding at least the components of component (ii) as described above. Further details of the polymer composition are also disclosed herein.

(108) In one embodiment, the polymer composition has a ShoreD hardness of less than 32-38, as measured by ASTM D2240 (compression molded sample). The aforementioned properties can, e.g., be determined by using the polymer composition in the form of a hollow cable with conductors removed according to EN 50363-8.

(109) The process for preparing an elongated article as disclosed herein may comprise the steps of:

(110) (i) providing an inner structure, preferably including one or more elements including a static/moving current medium or communication medium;

(111) (ii) compounding the components of the polymeric composition and then extrusion of the polymeric composition as described herein onto the one or more elements; and

(112) (iii) obtaining said elongated article.

(113) The step of compounding and extrusion is performed in two steps and in different devices: (iia) a compounding step, e.g. in a mixer, and afterwards (iib) the extrusion step in an extruder.

EXAMPLES

(114) The following examples describe the present invention in detail, but are not to be construed to be in any way limiting for the present invention.

(115) VLDPE1 (Clearflex MQF0 of eni/versalis): Is a linear very low density polyethylene (VLDPE) having a density in the range from 0.85 g/cm.sup.3 to 0.93 g/cm.sup.3, as measured according to ISO 1183, and having a melting point of above 110 C. It has a melt flow index of 8-15 as determined according to ASTM1238 (190 C./2.16 kg; g/10).

(116) VLDPE2 (Clearflex CLDO of Polimeri Europa, Eni): Is a linear very low density polyethylene (VLDPE) having a density in the range from 0.85 g/cm.sup.3 to 0.93 g/cm.sup.3, as measured according to ISO 1183, and having a melting point of above 110 C. It has a melt flow index of 2-5 as determined according to ASTM1238 (190 C./2.16 kg; g/10 min).

(117) POE1 (Engage 8842, random octene copolymer): Is an ultra-low density random ethylene-octene copolymer having a glass transition temperature of below 50 C. and having a melting point of below 40 C.

(118) POE2 (Exact8203 of ExxonMobil, block octene copolymer): Is an ultra-low density random ethylene-octene copolymer having a glass transition temperature of below 50 C. and having to a melting point of below 40 C. The polymer has an MFI of 3.0 g/10 min, a density of 0.888 g/ccm, a melting point of 72 C., a glass transition temperature of <75 C. and a Vicat softening point of 51 C.

(119) POE3 (Engage HM7487 of the Dow Chemical Company, random octene copolymer): Is an ultra-low density random ethylene-octene copolymer having a glass transition temperature of below 50 C. and having a melting point of below 40 C. The polymer has an MFI of <0.5 g/10 min, a density of 0.862 g/ccm, a melting point of 37 C., a and a glass transition temperature of <57 C.

(120) The test method and sample preparation for the measurement of the elongation is performed as with a sheathing material described in EN 50363-8, wherein the elongated article without the one or more elements/the elongated article without the inner structure is subjected to the measurement.

(121) The compositions in the examples were extruded into cables using a HFFR extruder, with HFFR extrusion head and HFFR screw, at a temperature in the range from 100 C. up to 175 C. The process conditions can be chosen by a person skilled in the art.

Example-1

Composition 1

(122) Composition 1 is characterized by a combination of a VLDPE (VLDPE1), in an amount of 25 wt.-% and a block octene copolymer (POE2) in an amount of 10 wt.-%. At a high filler level of ATH (aluminum hydroxide) of 63%, the elongation was below 300%.

(123) TABLE-US-00001 Composition 1 25 % VLDPE1 10 % POE2 63 % ATH 1 % Antioxidant 1 % Coupling agent

(124) The measured elongation was <300%. Composition 1 passed the alternate bending test, EN 50396.

Example-2

Composition 2

(125) Composition 2 is characterized by a combination of two VLDPEs, i.e., VLDPE1 and VLDPE2, in a total amount of 32 wt.-%. The two VLDPEs are used in combination with a block octene copolymer (POE2). An additional low level of ATH (aluminum hydroxide) of 58% gives a high elongation.

(126) TABLE-US-00002 Composition 2 24 % VLDPE1 8 % VLDPE2 8 % POE2 58 % ATH 1 % Antioxidant 1 % Coupling agent

(127) The measured elongation was >300%. Reducing the ATH level from 63% to 58% reduces the flame retardancy.

Example-3

Composition 3

(128) Composition 3 is characterized by a combination of two VLDPEs, i.e., VLDPE1 and VLDPE2, in a total amount of 32 wt.-%. The two VLDPEs are used in combination with a random octene copolymer (POE3). Even at a high filler level of ATH (aluminum hydroxide) of 58%, a very high elongation was obtained.

(129) TABLE-US-00003 Composition 3 24 % VLDPE1 8 % VLDPE2 8 % POE3 58 % ATH 1 % Antioxidant 1 % Coupling agent

(130) The measured elongation was >400%. A comparison between Compositions 2 and 3 seems to confirm the concept underlying the present invention. That is, the specific combination and amounts of components provides the desired elongation.

Example-4

Composition 4 (Comparative Example)

(131) Composition 4 is characterized by a combination of two VLDPEs, i.e., VLDPE1 and VLDPE2, in a total amount of 32 wt.-%. The two VLDPEs are used in combination with a propylene-based elastomer.

(132) TABLE-US-00004 Composition 4 24 % VLDPE1 8 % VLDPE2 8 % Propylene-based elastomer (copolymer) 58 % ATH 1 % Antioxidant 1 % Coupling agent

(133) The measured elongation was <300%. The measured tensile strength was <7.5 MPa. A comparison between Compositions 3 and 4 seems to suggest that the use of a propylene-based elastomer does not provide a very high elongation.

Example-5

Composition 5 (Comparative Example)

(134) Composition 5 is characterized by a combination of EVA (ethylene vinyl acetate) in an amount of 16 wt.-%. The EVA is used in combination with a block octene copolymer (POE2).

(135) TABLE-US-00005 Composition 5 16 % EVA 15 % POE2 63 % ATH 1 % Antioxidant 5 % Coupling agent MAH-PE

(136) The measured elongation was <300%. The composition failed the hot pressure test (80 C.>50%). A comparison between the above compositions seems to suggest that the use of EVA does not provide a very high elongation and dimensional stability. Additionally, another coupling agent does not improve the properties.

Example-6

Composition 6 (Comparative Example)

(137) Composition 6 is characterized by a combination of two VLDPEs, i.e., VLDPE1 and VLDPE2, in a total amount of 28 wt.-%. The two VLDPEs are used in combination with an -olefin copolymer.

(138) TABLE-US-00006 Composition 6 21 % VLDPE1 7 % VLDPE2 7 % -olefin copolymer (Vestoplast 750) 63 % ATH 1 % Antioxidant 1 % Coupling agent

(139) The measured elongation was <300%. A comparison between the above compositions seems to suggest that the use of a random ethylene-octene copolymer is superior to the use of an -olefin copolymer regarding elongation at break.

Composition 7 (Comparative Example)

(140) Composition 7 is characterized by a combination of two VLDPEs, i.e., VLDPE1 and VLDPE2, in a total amount of 20 wt.-%. The two VLDPEs are used in combination with an amorphous propylene-ethylene copolymer and POE2.

(141) TABLE-US-00007 Composition 7 16 % VLDPE1 4 % VLDPE2 10 % POE2 5 % Amorphous propylene- ethylene copolymer, Eastoflex 1060PL 63 % ATH 1 % Antioxidant 1 % Coupling agent

(142) The measured elongation was >300%. The composition failed the hot pressure test (hot pressure test 80 C.>50%). The experiment seems to show how changing the polymer compositions results in deterioration of the properties.

Composition 8

(143) Composition 8 is characterized by a combination of two VLDPEs, i.e., VLDPE1 and VLDPE2, in a total amount of 18 wt.-%. The two VLDPEs are used in combination with a random octene copolymer (POE3) in an amount of 17%.

(144) TABLE-US-00008 Composition 8 14 % VLDPE1 4 % VLDPE2 17 % POE3 63 % ATH 1 % Antioxidant 1 % Coupling agent

(145) The measured elongation was >400%. The composition failed the hot pressure test (80 C.>50%). The example seems to suggest that the amount of POE was too high for mechanical stability at high temperatures but good for elongation at break at room temperature.

Composition 9

(146) Composition 9 is characterized by a combination of two VLDPEs, i.e., VLDPE1 and VLDPE2, in a total amount of 23 wt.-%. The two VLDPEs are used in combination with a random octene copolymer in an amount of 13%.

(147) TABLE-US-00009 Composition 9 20 % VLDPE1 3 % VLDPE2 13 % POE1 62 % ATH 1 % Antioxidant 1 % Coupling agent

(148) The measured elongation was >400%. The flexibility test was achieved with a test elongated article.

Composition 10

(149) Composition 10 is characterized by a combination of two VLDPEs, i.e., VLDPE1 and VLDPE2, in a total amount of 30 wt.-%. The two VLDPEs are used in combination with a random octene copolymer (POE1) in an amount of 10%.

(150) TABLE-US-00010 Composition 10 20 % VLDPE1 10 % VLDPE2 10 % POE1 58 % ATH 1 % Antioxidant 1 % Coupling agent

(151) The measured elongation was >430%. With this formulation, the flexibility test can be achieved with an elongated article with three inner elements, each having a cross-section of 1.5 mm.sup.2.

CITED LITERATURE

(152) EP1102282 A1

(153) DE3633056 A1

(154) WO 2010015876 A1

(155) WO 2013030795 A1

(156) WO 2002026879 A1

(157) WO 2007032573 A1

(158) WO 2008014597 A1 and

(159) WO 2010024602 A2