Cable with flame-retardant multi-layer sheathing

Abstract

A cable (10) with a flame-retardant sheath (12) comprising: a core (18) containing at least one wire; an inner sheath (16) surrounding the core (18) comprising a thermoplastic elastomer and at least one flame retardant, wherein at least one flame retardant comprises one or more of the following: i) a phosphorus-containing flame retardant, ii) a nitrogen-containing flame retardant, iii) a melamine derivative, and iv) a nitrogen- and phosphorus-containing flame retardant; and an outer sheath (14) surrounding the inner sheath (16) comprising a thermoplastic elastomer and being substantially free of flame retardants, wherein the cable (10) passes the VW-1 flame test according to UL 1581, section 1080.

Description

TECHNICAL AREA

[0001] The present invention relates to a cable comprising a sheath consisting of two or more different sheaths, wherein the sheath exhibits superior chemical and weather resistance as well as an exceptionally smooth surface. In a preferred embodiment, the outermost sheath of the sheath is a thermoplastic elastomer that is essentially free of flame retardants, yet the sheath still provides desirable flame-retardant performance due to an inner sheath comprising a thermoplastic elastomer and a flame retardant, preferably a halogen-free flame retardant. The outermost sheath has highly desirable surface qualities. Methods for manufacturing the sheaths and flame-retardant cables are disclosed. STATE OF THE ART

[0002] In addition to insulating or otherwise isolating a wire or group of wires from the environment, coverings, such as sheaths, sleeves, or the like, must meet several other requirements, including, but not limited to, excellent extrusion properties, chemical resistance, weather resistance, flame retardancy, stiffness, flexibility, and good surface aesthetics, such as a soft and supple feel. These properties are particularly important for applications involving cables used in consumer electronics.

[0003] Various compositions were used for forming sheaths for wires and cables, including multiple layers with a variety of additives and components. Examples of such compositions are described in the following publications.

[0004] US 2014 / 0234620 describes a wire or cable comprising a flame-retardant-free thermoplastic inner sheath and an outer sheath with a composition based on the mass of the composition comprising (a) 10 wt.% to 90 wt.% of a TPU-containing synthetic resin, (b) 5 wt.% to 90 wt.% of a metal hydrate, (c) 2 wt.% to 50 wt.% of a nitrogen-containing phosphorus flame retardant, and (d) 2 wt.% to 50 wt.% of a liquid phosphate modifier, wherein the outer sheath is in contact with the insulating covering and wherein the outer sheath has a thickness of more than zero to 0.8 mm.

[0005] US 2013 / 0306350 describes a power cable with a claimed temperature resistance of at least 90 °C and, in particular, fire-resistant properties, which meets the requirements of UL83 standard (equivalent to CSA Standard 022.2 No. 75-08) and is consequently halogen-free, wherein the cable contains at least one strand, including a conductor and a flame-retardant, temperature-resistant, halogen-free insulating layer surrounding the conductor. The strand is surrounded by a polyamide sheath containing a polymer mixture, in particular polyamide. The sheath rests on the insulating layer of the strand, or the cable has an intermediate layer forming an intermediate sheath that rests against the insulating layer of at least two strands and against the sheath surrounding the intermediate layer, also referred to as the intermediate sheath.

[0006] US 6,178,277 describes a multilayer reinforced and stabilized cable construction comprising a core and a non-metallic sheath, with a barrier and protective layers, and two or more outer reinforcing layers. To enable control of the cable's mechanical and barrier properties, the barrier and protective layers and / or reinforcing layers are oriented at various angles in a controlled manner using fiber reinforcements or lamellar barriers.

[0007] For wire sheaths, manufacturers and end users require compliance with specific flame-retardant standards. In certain designs, relatively high amounts of flame retardants may be necessary, e.g., 35 wt% when halogen-free flame-retardant thermoplastic elastomer compositions are used. Halogen-free polymer systems tend to be more polar than polyolefins. One of the problems associated with such polymer systems is poor surface quality, e.g., rough, uneven surfaces, most likely caused by high levels of halogenated flame retardants. Another problem is poor chemical resistance due to the polymer system and the halogen-free flame retardants.Another problem is that the encapsulations can be easily discolored by skin oils, everyday products, or household items, a process that is to some extent stimulated by the use of skin oils. Some halogen-free flame-retardant encapsulations formed with certain intumescent flame retardants, such as those containing BPA, can exhibit poor weather resistance, resulting in significant yellowing and undesirable color changes. These issues render halogen-free flame-retardant encapsulations unsuitable for consumer electronics applications. PRESENTATION OF THE INVENTION

[0008] In view of the above, the aforementioned and other problems can be solved by the present invention, which provides a multilayer sheath for a wire (or wires) that has desirable flame-retardant and surface properties of the outer sheath.

[0009] Another embodiment of the present invention provides a flame-retardant cable having an outer sheath with a smooth outer surface that is resistant to chemicals and weathering.

[0010] Another embodiment of the present invention is the provision of a flame-retardant cable which surprisingly passes the VW-1 flame test according to UL 1581, section 1080, wherein the cable has an outer sheath containing few or no flame-retardant components, since flame retardants are provided in an inner sheath and consist of halogen-free flame retardants.

[0011] Another object of the present invention is the provision of a co-extruded wire sheath, including an inner sheath comprising a preferably halogen-free flame retardant, a thermoplastic elastomer composition and an outer sheath made of thermoplastic elastomer with few or no flame retardants.

[0012] In one aspect, a cable is disclosed comprising: a core containing at least one wire; an inner sheath surrounding the core comprising a styrene block copolymer and halogen-free flame retardants; and an outer sheath surrounding the inner sheath comprising a styrene block copolymer and being substantially free of flame retardants, wherein the cable passes a VW-1 flame test in accordance with UL 1581, Section 1080.

[0013] In another aspect, a cable is disclosed comprising a core with at least one wire, an inner sheath surrounding the core composed of halogen-free flame retardants, and an outer sheath surrounding the inner sheath made of styrene block copolymer and being substantially free of flame retardants, wherein the outer sheath has a weather resistance of less than 8 ΔE at 150 kJ / m as measured according to the automotive interior standard SAE J2412. 2 exhibits. List of characters

[0014] The invention is more understandable and other features and advantages become more apparent when the detailed description is read and viewed together with the drawings: Fig.Figure 1 shows a cross-sectional view of a wire comprising a core, an inner sheath containing a flame-retardant thermoplastic elastomer, and an outer sheath that is essentially free of flame retardants and comprises a thermoplastic elastomer that has a silky smooth surface and desirable chemical and weather resistance. DETAILED DESCRIPTION OF THE INVENTION

[0015] In this technical description, all specified numbers represent an individual set value in one embodiment, regardless of whether the word "approximately" or "about" or a similar word is used in conjunction with the value. When terms such as "approximately" or "about" are used in conjunction with a value, the range of numbers may also vary in different other, independent embodiments, e.g., by 1%, 2%, 5%, or more.

[0016] Numerical ranges encompass all values ​​from the lowest to the highest, in increments of one unit, provided there is a separation of at least two units between each lower and each higher value. If the values ​​for a compositional, physical, or other property, such as molar mass, weight percent, etc., range from 100 to 1000, all individual values, such as 100, 101, 102, etc., as well as subranges, such as 100 to 144, 155 to 170, 197 to 200, etc., are explicitly enumerated. For ranges with values ​​less than one or with fractions greater than one (e.g., 1.1, 1.5, etc.), 0.0001, 0.001, 0.01, or 0.1, respectively, is considered one unit. For ranges with single-digit numbers below ten (e.g., 1 to 5), 0.1 is normally considered one unit. These are only examples to illustrate the intention.All possible combinations of numerical values ​​between the lowest and highest listed value are considered explicit disclosures in this disclosure. Numerical ranges are provided in this disclosure, among other things, to indicate the number of components in the composition.

[0017] “Wire” and similar terms refer to a strand or strand of a conductive metal, such as copper, or a strand of optical fibers.

[0018] "Cable" and similar terms refer to a wire or optical fiber within a covering, which may be, for example, an insulating sheath or a protective jacket. A cable typically consists of two or more wires bundled together and generally enclosed within a covering. The individual wires within the covering may be bare, sheathed, or insulated. Cables may contain wires that can be either conductive metal strands or optical fibers. A cable can be used for low-, medium-, and / or high-voltage applications.

[0019] "Halogen-free" and similar terms refer to compositions that are completely or substantially free of halogens, i.e., they contain < 2000 mg / kg halogen, as measured by ion chromatography or a similar analytical method. A halogen content below this amount is considered negligible with regard to the effectiveness of the composition as a wire or cable sheath.

[0020] “Substantially free of” and similar terms refer to the composition or component containing less than 5 parts or 1 part, preferably less than 0.5 parts and preferably less than 0.1 parts per 100 parts by weight of the composition or component.

[0021] “VW-1” is a flame test for cables, performed in accordance with UL-1581, Section 1080 of UL LLC, formerly Underwriters Laboratories (UL), as defined in this document.

[0022] Fig.Figure 1 shows a non-restrictive embodiment of a cross-sectional view of a cable according to the invention. 10 , which is a multi-layered covering 12 includes, including an outer shell 14 and an inner jacket 16 The cable 10 includes a core 18 , which contains at least one wire extending from the inner sheath 16 is enveloped, which in turn is enclosed by the outer shell 14 is encased. In a preferred embodiment, both the inner and outer jackets comprise thermoplastic elastomers. In a preferred embodiment, the inner jacket may contain a halogenated polymer or copolymer, such as polyvinyl chloride. The inner jacket is preferably located adjacent to and in contact with the outer jacket. However, the properties of the inner and outer jackets are different to fulfill the objective of the present invention. In particular, the material of the inner jacket is 16It is equipped with a halogen-free flame retardant, enabling the cable to pass a VW-1 flame test according to UL 1581, section 1080. In comparison, the outer sheath material is... 14 Essentially free of flame retardants, it contains components that synergistically provide desirable chemical and weather resistance as well as a smooth surface.

[0023] Surprisingly, it was found that despite the outer sheath being essentially free of flame retardants, the cable passes the VW-1 flame test according to UL 1581, section 1080, and consequently meets the flame retardancy standards required by certain wire and cable sheath manufacturers and end users. In one embodiment, the inner sheath is extruded around the core. In another embodiment, the outer sheath is extruded around or onto the inner sheath. In a preferred embodiment, the inner and outer sheaths are co-extruded onto the core. If desired, other methods can also be used to provide the core with an inner and outer sheath according to the invention.

[0024] To achieve the desired characteristics of the cable according to the invention, the outer sheath has a defined thickness relative to the combined thickness of the inner and outer sheaths. The outer sheath has a minimum thickness that can be used to achieve the desired chemical and weather resistance of the cable and also to impart certain surface characteristics to the cable that are desirable or convenient for the end user. The outer sheath has a maximum thickness at which the cable passes the VW-1 flame test according to UL 1581, Section 1080. The inner sheath has a sufficient thickness at which the cable can pass the VW-1 flame test.

[0025] In various embodiments of the present invention, the outer sheath has a thickness that is generally from about 0.5 percent to about 30 percent, desirablely from about 1 to about 20 percent, and preferably from about 3 to about 12 or about 15 percent of the total thickness of the inner and outer sheaths, which is measured perpendicular to a line of contact on the cable at only one point or at the radius of the cable if the cable has a substantially cylindrical or round cross-section.

[0026] In another aspect of the present invention, the cable is characterized by flame-retardant properties of each sheath. The compositions used to form the one or more inner sheaths pass the UL 94 VB test with a rating of V-0 at a thickness of 3.175 mm (1 / 8 in). However, the composition used in various embodiments of the present invention for forming the outer sheath fails the UL 94 VB test at a thickness of 3.175 mm (1 / 8 in). Accordingly, it is surprising and unexpected that the cables according to the invention, with an outer sheath exposed to the environment, pass the VW-1 flame test according to UL 1581.

[0027] The cables according to the invention have an outer sheath with a minimum weather resistance to ensure that the cables are suitable for exposure to the intended environment and that the desired appearance is maintained. A method for characterizing the weather resistance is specified in SAE J2412. In various embodiments of the present invention, the compositions used for forming the outer sheath according to the invention generally have a weather resistance of less than 8 dE, 150 kJ / m. 2 Desirable values ​​are less than 5 dE, 150 kJ / m² 2 and preferably less than 3 L1E, 150 kJ / m² 2 according to measurements in accordance with SAE J2412 at a blackboard temperature of 89 °C and a chamber temperature of 63 °C.

[0028] The cables according to the invention are also characterized by their desirable chemical resistance. This chemical resistance enhances the cable's ability to resist staining due to contact with skin oils, everyday products, or common household products. The chemical resistance of the compositions used for the outer sheath according to the invention is characterized by the following chemical resistance test: Bone-shaped plaques, 1.905 mm (0.075 in) thick and 6.35 mm (0.25 in) wide, were die-cut from plaques injection-molded at 187 °C to 221 °C (370 °F to 430 °F). A stimulant was evenly applied to the surface of the specimen using a cotton swab. The specimens were conditioned at 65 °C for three days. The tensile elongation to fracture was measured according to ASTM D412 before and after chemical exposure.Chemical resistance is quantified by the percentage change in tensile strain upon fracture of the specimen. The smaller the percentage change, the greater the chemical resistance of the specimen.

[0029] As described above, the coating comprises an inner and outer shell, which contain thermoplastic elastomers. The following components can be used to form the different shell layers of the coating. Thermoplastic elastomer, general styrene block copolymers

[0030] In various embodiments, the compositions of the inner and / or outer shell comprised one or more styrene block copolymers. In a preferred embodiment, the styrene block copolymers have a hard block (A) comprising aromatic vinyl or monoalkenylar repeat units and at least one soft polymer block (B) containing two or more repeat units, which may be identical or different, and which are obtained separately from olefin monomers. The styrene block copolymer can be, for example, a triblock copolymer (ABA), a tetrablock, or a higher multiblock copolymer. In a preferred embodiment, the styrene block copolymer is a triblock copolymer (ABA) with two hard blocks.

[0031] The number-mean molar mass and distribution of all types of styrene block copolymer (SBC) described in this application are measured by gel permeation chromatography (GPC). The SBC is dissolved in a suitable solvent, such as THF (normally 0.001–0.010 wt%), and the appropriate amount is injected into a GPC instrument. A suitable GPC vessel is the Waters Breeze Dual Pump LC offered by Waters of Milford, MA. The GPC analysis is performed at an appropriate elution rate (1 to 10 ml / min). The molar mass distribution is characterized by the signals from the UV and refractive index sensors, and the number-mean molar masses are calculated using a calibration curve generated from a series of polystyrenes with narrow molar mass distributions, with peak molecular masses of 500 to 1,000,000 being used as a standard.

[0032] Each hard polymer block (A) may have two or more identical or different aromatic vinyl repeat units. The block copolymer may, for example, contain blocks (A) that are styrene / alphamethylstyrene copolymer blocks or styrene / butadiene random or gradient copolymer blocks, as long as a majority of the repeat units in each hard block are aromatic vinyl unit cells. In one embodiment, the (A) blocks are aromatic vinyl compound homopolymer blocks. The term “aromatic vinyl” also includes aromatic hydrocarbons of the benzene series, such as styrene and its analogs and homologs, including o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, alpha-methylstyrene, and other ring-alkylated styrenes, in particular ring-methylated styrenes, and other polycyclic aromatic monoalkenyl compounds, such as vinylnaphthalene, vinylanthracene, and similar compounds.The preferred aromatic vinyl compounds are monovinyl monocyclic aromatics, such as styrene and alpha-methylstyrene, with styrene being the most preferred. If three or more different repeating units are present in the hard polymer block (A), the repeating units are grouped together in any desired form, such as a random shape, block shape, and gradient shape.

[0033] Alternatively, the hard polymer block (A) can contain, in addition to structural units derived from aromatic vinyl compounds, small amounts of structural units derived from other copolymerizable monomers. The desirable proportion of structural units derived from other copolymerizable monomers is 30 wt.% or less, and preferably 10 wt.% or less, based on the total mass of the hard polymer block (A). Examples of other copolymerizable monomers include, but are not limited to, 1-butene, pentene, hexene, conjugated dienes such as butadiene or isoprene, methyl vinyl ether, and other monomers.

[0034] In various embodiments, the hydrogenated styrene block copolymers, including styrene or monoalkenylars in a soft polymer block (B) with one or more olefin monomers and diene monomers, contain said blocks formed randomly. Non-restrictive examples of the styrene block copolymers in which styrene or monoalkenylars are randomly distributed in a soft polymer block (B) are taught in U.S. Patents 6,031,053 and 6,197,889. Persons skilled in the art are aware of how to carry out the hydrogenation.

[0035] The soft polymer block (B) of the styrene block copolymer contains two or more identical or different structural units. The soft polymer block (B) can be obtained from olefin monomers, which generally contain 2 to approximately 12 carbon atoms and can include, for example, ethylene, propylene, butylene, isobutylene, etc. If the structural units of the soft polymer block (B) are derived from three or more repeating units, the structural units can be arranged in a form such as random, gradient, block, or a combination thereof. In one embodiment, the soft polymer block contains no unsaturated bonds.

[0036] In further embodiments of the present invention, the styrene block copolymer can comprise at least one soft polymer block (B) with two or more repeating units, which may be identical or different and are obtained separately from one or more olefin monomers and a diene monomer. If the diene monomer is present, the styrene block copolymer is preferably hydrogenated or substantially hydrogenated. The conjugated diene monomers preferably contain 4 to approximately 8 carbon atoms, for example, and without limitation, 1,3-butadiene (butadiene), 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene (piperylene), 1,3-hexadiene, and the like. Consequently, in one embodiment, the soft polymer block (B) can contain structural units obtained from one or more olefin monomers and diene monomers.As described above, the structural units can be combined into one shape if the structural units of the soft polymer block (B) are obtained from three or more repeating units.

[0037] The styrene block copolymers can be prepared using bulk, solution or emulsion processes or other methods known from the prior art.

[0038] Alternatively, the soft polymer block (B) can contain small amounts of structural units derived from other copolymerizable monomers in addition to the structural units described above. In this case, the proportion of the other copolymerizable monomers is generally 30 wt.% or less, and preferably 10 wt.% or less, based on the total mass of the soft polymer block (B) of the styrene block copolymer. Examples of other copolymerizable monomers include, but are not limited to, styrene, p-methylstyrene, α-methylstyrene, and other monomers that can undergo ionic polymerization.

[0039] Alternatively, the styrene block copolymer can be a functionalized styrene block copolymer, such as an acid- or anhydride-functionalized block copolymer, prepared, for example, by grafting an acid moiety or its derivative into the styrene block copolymer via a free-radical-induced reaction. Suitable monomers for grafting include, for example, unsaturated mono- and polycarboxylic acids and anhydrides containing approximately 3 to 10 carbon atoms. Such monomers include, for example, fumaric acid, itaconic acid, citraconic acid, acrylic acid, maleic anhydride, itaconic anhydride, and citraconic anhydride, or similar compounds. Suitable functionalized styrene block copolymers generally contain approximately 0.1 to approximately 10 wt%, preferably approximately 0.2 to approximately 5 wt%, of the grafted monomer, based on the total mass of the styrene block copolymer.Grafting reactions can be carried out in solution or by melt mixing of the base block copolymer and the acid / anhydride monomer in the presence of a free-radical initiator known from the prior art; see, for example, US Patent 6,653,408, which is incorporated herein in its entirety by reference. Suitable functionalized block copolymers are available from KRATON Polymers, Kuraray, Asahi-Kasei, BASF, and similar suppliers.

[0040] In various embodiments, the styrene block copolymers also include, without limitation, styrene-butadiene-styrene (SBS), styrene-butadiene / butylene-styrene (SBBS), styrene-isoprene-styrene (SIS), styrene-ethylene / propylene-styrene (SEPS), styrene-ethylene / propylene (SEP), styrene-ethylene / butylene-styrene (SEBS), styrene-ethylene / ethylene / propylene-styrene (SEEPS) and styrene-isobutylene-styrene (SIBS).

[0041] Styrene block copolymers are known from the prior art and are available from various suppliers, e.g. Kraton Polymers in Houston, Texas, as Kraton; Kuraray Co., Ltd. in Tokyo, Japan as SEPTONTM styrene block copolymers, LCY Chemical Industry Corp as Globalprene® and TSRC Corporation in Taiwan as Taipol.

[0042] The amount of one or more styrene block copolymers used in the compositions according to the invention is generally from about 1 to about 40 or about 45 or about 50 parts, desirable are about 10 to about 35 parts and preferred are about 10 or about 15 to about 30 parts based on 100 parts total mass of the composition.

[0043] Copolymer block-containing styrene block copolymers with controlled distribution

[0044] The styrene block copolymer with controlled distribution, used in one or more claddings, contains at least one first block of a monoalkenylar, such as styrene, and a second block of a diene-monoalkenylar copolymer with controlled distribution. Thus, the block copolymers can be any diblock or higher block copolymer. In the case of a diblock copolymer, one block is an alkenylar-based block, and thus polymerized is a second block of the diene-alkenylar copolymer with controlled distribution. Triblock or higher multiblock copolymers comprise at least one alkenylar-based block and at least one diene-alkenylar copolymer block with controlled distribution.In a preferred embodiment, the triblock composition used as end blocks comprises alkenylarene-based blocks and a middle block of a controlled-distribution copolymer composed of diene and alkenylarene. When a triblock copolymer composition is prepared, the controlled-distribution copolymer block can be designated as "B" and the alkenylarene-based block as "A". The ABA triblock compositions can be prepared either by sequential polymerization or coupling. In one embodiment, using the sequential solution polymerization technique, the monoalkenylarene is introduced first to create a relatively hard aromatic block, followed by the introduction of the controlled-distribution diene / alkenylarene mixture to form the middle block, and finally by the introduction of the monoalkenylarene to form the end block.

[0045] In one embodiment, a process for producing a styrene block copolymer containing a controlled distribution is described in US Patent 7,169,848, which is incorporated herein by reference. For the purposes of this document, “controlled distribution” refers to a molecular structure having the following features: (1) end regions adjacent to the monoalkenylar homopolymer blocks (“A”) that are rich in (i.e., containing more than the average amount of) conjugated diene units; (2) one or more regions not adjacent to the A blocks that are rich in (i.e., containing more than the average amount of) monoalkenylar units; and (3) an overall structure with relatively low blockiness. For the purposes of this document, “rich in” means an above-average amount, preferably more than 5% of the average amount.Prior to hydrogenation, the styrene in the rubber block portion is copolymerized and incorporated into a controlled distribution, featuring end regions rich in diene units (e.g., butadiene, isoprene, or a mixture thereof) and a central region rich in styrene units. Hydrogenation of such polymers was performed under standard conditions, resulting in the reduction of more than 95% of the dienes with double bonds in the rubber block. The process for producing a selectively hydrogenated styrene block copolymer is described in US Patent 7,169,848, Bening et al.

[0046] Styrene blockiness is simply the percentage of blocky styrene relative to the total styrene units: Blöckigkeit% = 100 mal ( Blöckige Styroleinheiten / Gesamte Styroleinheiten )

[0047] Expressed in this way, polymer-Bd-S-(S)nS-Bd polymer, where n is greater than zero, is defined as a blocky styrene. For example, if n is equal to 8 in the preceding example, then the blockiness index would be 80%. It is preferred that the blockiness index be less than 40. For some polymers with styrene contents of 10% to 40% by weight, it is preferred that the blockiness index be less than 10. In a preferred embodiment of the present invention, the copolymer block in question has two distinct regions with controlled distribution: conjugated diene-rich regions at the end of the block and a monoalkenylar-rich region near the middle or center of the block.A monoalkenylar / conjugated diene copolymer block with a controlled distribution is desired, in which the proportion of monoalkenylar units gradually increases to a maximum near the middle or center of the block and then gradually decreases until the polymer block is completely polymerized.

[0048] The alkenylarene can be selected from styrene, alpha-methylstyrene, para-methylstyrene, vinyltoluene, vinylnaphthalene, and para-butylstyrene, or mixtures thereof. Of these, styrene is particularly preferred and is commercially available from a variety of manufacturers and is relatively inexpensive. The conjugated dienes for use herein are 1,3-butadiene and substituted butadienes, such as isoprene, piperylene, 2,3-dimethyl-1,3-butadiene, and 1-phenyl-1,3-butadiene, or mixtures thereof. Of these, 1,3-butadiene is particularly preferred.

[0049] For controlled distribution or the B-block, the weight percent of monoalkenylars in each B-block is between approximately 10 weight percent and approximately 75 weight percent, preferably between approximately 25 weight percent and approximately 50 weight percent for selectively hydrogenated polymers.

[0050] To ensure significant elastomeric performance while maintaining desirable high Tg and strength properties, as well as desirable transparency, it is preferred that the alkenylar content of the triblock and multiblock polymer be greater than approximately 20 wt.%, preferably from approximately 20 wt.% to approximately 80 wt.%. This means that essentially the entire remaining content, which is part of the diene / alkenylar block, consists of diene. It is also important to control the molecular weight of the different blocks. For an AB diblock, the desired block weights are 3,000 to 60,000 for the monoalkenylar A-block, and 30,000 to 300,000 for the conjugated diene / monoalkenylar B-block with controlled distribution. Preferred ranges are 5,000 to 45,000 for the A-block and 50,000 to 250,000 for the B-block. For the triblock, which can be a sequential ABA or coupled (AB)2X block copolymer, the A-blocks should be 3,000 to 60,000.The B-blocks for the sequential block should have a molecular weight of 000, preferably 5,000 to 45,000, while the B-block for the sequential block should have a molecular weight of 30,000 to 300,000 and the two B-blocks for the coupled polymer should have half that amount. The overall average molecular weight for the triblock copolymer should be 40,000 to 400,000 and for the radial copolymer 60,000 to 600,000. For the tetrablock copolymer ABAB, the block size for the B-end block should be approximately 2,000 to approximately 40,000, and the other blocks should be similar to the sequential triblock copolymer. These molecular weights are determined with high precision by light scattering measurements and are expressed as number-averaged molecular weights.

[0051] The block copolymer with controlled distribution can be hydrogenated in various embodiments. A preferred hydrogenation is the selective hydrogenation of the diene moiety of the final block copolymer; alternatively, both the "B" blocks and the "A" blocks can be hydrogenated, or only a portion of the "B" block can be hydrogenated.

[0052] Hydrogenation can be carried out by any of several hydrogenation processes or selective hydrogenation processes known from the prior art. Such hydrogenation has been carried out, for example, using processes such as those taught in U.S. Patents 3,595,942; 3,634,549; 3,670,054; 3,700,633 and Re. 27,145 (incorporated by reference into this document). These processes hydrogenate polymers containing aromatic or ethylenic unsaturations and are based on the function of a suitable catalyst. Such catalysts or catalyst precursors preferably comprise a Group VIII metal, such as nickel or cobalt, combined with a suitable reducing agent, such as an aluminum alkyl or hydride of one of the Group IA, II-A, and III-B periodic table elements, in particular lithium, magnesium, or aluminum.This preparation is carried out in a suitable solvent or diluent at a temperature of approximately 20 °C to approximately 80 °C. Other suitable catalysts include titanium-based catalyst systems. The hydrogenation can be carried out under conditions such that at least approximately 90 percent of the diene double bonds are reduced and between zero and 10 percent of the arene double bonds are reduced. In a preferred range, at least approximately 95 percent of the conjugated diene double bonds are reduced, and more preferably, approximately 98 percent of the conjugated diene double bonds are reduced. Alternatively, it is possible to hydrogenate the polymer in such a way that the aromatic unsaturation is also reduced beyond the aforementioned level of 10 percent. Such comprehensive hydrogenation is usually achieved at higher temperatures.In this case, 90 percent or more of the double bonds of both the conjugated diene and the arene can be reduced.

[0053] Alternatively, the block copolymer of the present invention can be functionalized in a number of ways. One method is treatment with an unsaturated monomer containing one or more functional groups or their derivatives, such as carboxylic acid groups and their salts, anhydrides, esters, imide groups, amide groups, and acid chlorides. Preferred monomers to be grafted onto the block copolymers are maleic anhydride, maleic acid, fumaric acid, and their derivatives. A further description of the functionalization of such block copolymers can be found in Gergen et al., U.S. Patent No. 4,578,429 and U.S. Patent No. 5,506,299. In another way, the selectively hydrogenated block copolymer of the present invention can be functionalized by grafting silicon- or boron-containing compounds onto the polymer, as described in U.S. Patent No. 4,882,384.In another way, the block copolymer of the present invention can be contacted with an alkoxy-silane compound to form a silane-modified block copolymer. In yet another way, the block copolymer of the present invention can be functionalized by grafting at least one ethylene oxide molecule onto the polymer, as taught in U.S. Patent No. 4,898,914, or by reacting the polymer with carbon dioxide, as taught in U.S. Patent No. 4,970,265. Furthermore, metal atoms can be introduced into the block copolymers of the present invention, as taught in U.S. Patents Nos. 5,206,300 and 5,276,101, wherein the polymer is contacted with an alkali metal alkyl, such as lithium alkyl. And furthermore, the block copolymers of the present invention can be functionalized by grafting sulfo groups onto the polymer, as taught in Patent No. 5,516,831.All patents mentioned in this paragraph are incorporated into this application by reference.

[0054] In various embodiments of the invention, the monoalkenylar is present in a total mass of more than 20% and preferably more than 35%, based on the total mass of the controlled-distribution styrene block copolymer. In various embodiments, the soft or B block of the controlled-distribution copolymer block has a monoalkenylar content of less than 30 wt.%, preferably less than 29 wt.%. The controlled-distribution block copolymer of the present invention may comprise copolymers marketed under the trade name Kraton A® by Kraton Polymers, with Kraton A1536 and A1535 serving as examples.

[0055] In various embodiments of the invention, if any, the styrene block copolymers with controlled distribution in the inventive sheath compositions are used in quantities of approximately 5 to approximately 50 parts, quantities of approximately 10 or approximately 15 to approximately 50 parts are desirable, and quantities of approximately 10 to approximately 35 parts based on 100 parts according to the total mass of the composition are preferred. Other thermoplastic elastomers

[0056] Instead of or in addition to the use of styrene block copolymers, the thermoplastic elastomer of one or more inner and outer jackets can be a thermoplastic polyolefin, thermoplastic polyurethane, thermoplastic copolyester or thermoplastic polyamide. Polyolefins

[0057] In one embodiment, one or more compositions according to the invention comprise one or more polyolefins, which, in the manner used herein, are defined as one or more polyolefin polymers and a polyolefin copolymer, unless otherwise specified. Suitable polyolefins for the compositions according to the invention include amorphous or crystalline homopolymers or copolymers of two or more identical or different monomers derived from alpha monoolefins, having 2 to approximately 12 carbon atoms and preferably 2 to approximately 8 carbon atoms. Examples of suitable olefins are, among others, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 2-methyl-1-propene, 3-methyl-1-pentene, 4-methyl-1-pentene, 5-methyl-1-hexene, and combinations thereof.Polyolefins include, without limitation, low-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene (isotactic and syndiotactic), ethylene / propylene copolymers, ethylene / α-olefin copolymers, and polybutene. Polyolefin copolymers may also comprise a larger weight fraction of one or more olefin monomers and a smaller amount of one or more non-olefin monomers, such as vinyl monomers, including vinyl acetate or a diene monomer, etc. Polar polyolefin polymers include, for example, ethylene acrylate and ethylene vinyl acetate. In a preferred embodiment, EVA is used, which has a vinyl acetate content greater than 5 percent. Generally, a polyolefin copolymer comprises less than 40 percent by weight of a non-olefin monomer; less than 30 percent by weight is desirable, and less than approximately 10 percent by weight, or even no non-olefin monomer at all, is preferred.

[0058] In another embodiment, the polyolefin can comprise at least one functional group per chain, or it can be a mixture of non-functionalized and functionalized polyolefins. Functional groups can be incorporated into the polyolefin, for example, by including one or more non-olefin monomers during the polymerization of the polyolefin. Examples of functional groups include, but are not limited to, anhydride groups such as maleic anhydride, itaconic anhydride, and citraconic anhydride; acrylates such as glycidyl methacrylate; acid groups such as fumaric acid, itaconic acid, citraconic acid, and acrylic acid; functional groups of epoxides; and functional groups of amines. Polyolefins containing functional groups and methods for forming them are known to persons competent in this field. Functionalized polyolefins are commercially available from suppliers such as Uniroyal, Atofina, and DuPont. Epoxy-modified polyethylenes are available from Atofina as LOTADER®.Acid-modified polyethylenes are available from DuPont as FUSABOND®.

[0059] Polyolefin polymers and copolymers are commercially available under various names from suppliers including, but not limited to, Chevron, Dow Chemical, DuPont, ExxonMobil, Huntsman Polymers, Ticona and Westlake Polymer.

[0060] If present, the polyolefins are in the range of approximately 0 to approximately 70 parts, with desirable amounts of approximately 5 to approximately 60 parts and preferably approximately 5 to approximately 50 parts by weight, based on a total of 100 parts by weight of the entire composition. Other polymers

[0061] In various embodiments, other polymers can be added to the compositions according to the invention of one or more sheaths in the amounts specified for the polyolefins, provided that such polymers do not interfere with the desired performance of the compositions and the structures formed therewith. Examples of additional polymers include, but are not limited to, polyamides such as nylon, acrylonitrilebutadiene styrene copolymers (ABS), acrylonitrile ethylene styrene (AES), styreneacrylonitrile copolymer (SAN), halogenated polymers such as polyvinyl chloride, polycarbonates, acrylic polymers, PET, PBT, polyester, TPU (also TPU with a bio-based polyester block), polyetherblockamide (PEBA), polyphenylene ether (PPE), and polylactic acid (PLA).In one embodiment, the compositions according to the invention further comprise a polar polymer comprising one or more of the substances ethylene vinyl acetate, maleated polyolefin, maleated styrene block copolymer, maleated EPDM, acrylic polymer and maleic anhydride / olefin copolymer, wherein the polar polymer is present in amounts of approximately 1 to approximately 10 wt.% based on the total mass of the composition (100 wt.%). Flame retardant

[0062] At least one inner or non-surface layer of the casing comprises at least one flame retardant. In preferred embodiments, the flame retardants used are halogen-free. General classes or types of usable halogen-free flame retardants include, for example, without limitation, phosphorus-containing flame retardants, nitrogen-containing flame retardants, melamine derivatives, metal hydroxides, metal hydrates, expandable graphite, and organosylsilicates.

[0063] Phosphorus-containing flame retardants also include phosphate esters. Phosphate esters comprise aromatic and aliphatic phosphate esters, as well as their oligomers and polymers. Examples of aliphatic phosphate ester flame retardants include trimethyl phosphate, tributyl phosphate, tri(2-ethylhexyl) phosphate, tributoxyethyl phosphate, monoisodecyl phosphate, and 2-acryloyloxyethyl acid phosphate. Examples of aromatic phosphate esters include trixylenyl phosphate, tris(phenylphenyl) phosphate, trinaphthyl phosphate, cresyl diphenyl phosphates, xylenyl diphenyl phosphate, 2-ethylhexyl diphenyl phosphate, phosphoric acid dodecyl ester diphenyl ester, and diphenyl-2-methacryloyloxyethyl phosphate. Examples of aromatic bis(phosphate) esters include resorcinol bis(diphenyl phosphate), resorcinol bis(dixylenyl phosphate), resorcinol bis(dicresyl phosphate), hydroquinone bis(dixylenyl phosphate), bisphenol A bis(diphenyl phosphate) and tetrakis (2,6-dimethylphenyl)1,3-phenylene bisphosphate.Preferred phosphate esters in one embodiment comprise disphenyl-A bis(diphenyl phosphate), 2-ethylhexyl diphenyl phosphate, and resorcinol bis(diphenyl phosphate). The liquid, phosphorus-containing flame retardants are free of halogen atoms.

[0064] Phosphorus-containing flame retardants include phosphates, pyrophosphates, metaphosphates, and polyphosphates. Nitrogen- and phosphorus-containing flame retardants include melamine pyrophosphate, melamine orthophosphate, monoammonium phosphate, diammonium phosphate, ammonium pyrophosphate, phosphoric acid amide, melamine polyphosphate, ammonium polyphosphate, piperazine polyphosphate, and polyphosphoric acid amide.

[0065] Other examples of halogen-free flame retardants include metal hydrates such as aluminum hydrate and magnesium hydrate, metal hydroxides such as magnesium hydroxide and aluminum trihydroxide (ATH), metal oxides such as titanium dioxide, silicon dioxide, aluminum oxide, bentonite, hectorite, montmorillonite, swollen graphite, huntite, antimony trioxide, potassium oxide, zirconium oxide, zinc oxide and magnesium oxide.

[0066] In some embodiments of the present invention, the flame retardant packings described in US Patent No. 9,156,978 can be used, and the patent is hereby incorporated herein by reference.

[0067] Phosphorus-containing flame retardants are available from suppliers such as Adeka Palmarole or Amfine Chemical Corporation (USA) as IL-6, IL-7, FP-600, FP-2100J, FP-2200, and ICL-IP as Fyrol BDP. Polyphosphorus homopolymers and copolymers are available as FRX 100 and FRX C035 from FRX Polymers. Various flame retardants are also available, such as Exolit from Clariant and Budit from Budenheim.

[0075] The amount of halogen-free flame retardant can vary depending on the flame retardant used in at least one inner jacket or jacket not located on the surface. If two or more inner jackets are present, the amounts of halogen-free flame retardant in each jacket can differ independently. The halogen-free flame retardants present in an inner sheath are in quantities of generally approximately 5 to approximately 70 parts, desirablely approximately 10 to approximately 65 parts, and preferably approximately 15 to approximately 10 parts.60 parts are present, based on a total of 100 parts by weight of the components used to form the mantle. Additions

[0068] The coatings according to the invention can comprise further additives, including, but not limited to, light stabilizers, antioxidants, other halogen-free flame retardants (inner coatings), pigments, peroxides, heat stabilizers, processing aids, mold release agents, flow improvers, nanoparticles, foams, platelet fillers, and non-platelet fillers. Examples of fillers for use in the compositions include, but are not limited to, one or more of the following substances: calcium carbonate, talc, zeolite, titanium dioxide, carbon black, barium sulfate, mica, glass fibers, whiskers, carbon fibers, magnesium carbonate, glass powder, metal powder, kaolin, graphite, and molybdenum disulfide. Suitable fillers include bio-based fillers, e.g., various fibers, cellulose, and / or lignin. Plasticizers

[0069] In various embodiments, the one or more coatings according to the invention contain plasticizers, which, for the purposes of this document, refer to mineral oil, synthetic resin plasticizers, and vegetable oil. Oil-based plasticizers are generally mixtures of aromatic hydrocarbons, naphthenic hydrocarbons, and paraffin, i.e., aliphatic hydrocarbons. Those in which the carbon atoms forming paraffinic hydrocarbons constitute 50% or more of the total carbon atoms are referred to as "paraffin oils." Those in which the carbon atoms forming naphthenic hydrocarbons constitute 30% to 45% of the total carbon atoms are referred to as "naphthenic oils," and those in which the carbon atoms forming aromatic hydrocarbons constitute 35% or more are referred to as "aromatic oils." Examples of synthetic resin plasticizers include, among others...Without limitation, poly(alphaolefin) oligomers (PAO), polyisobutylene, polybutene, and GTL oil available from Shell. If present, the plasticizers are present in amounts ranging from 1 to 40 wt% and preferably from 5 to 30 wt% based on the total mass of the composition of the respective jacket. Examples

[0070] The examples described below serve to illustrate the features of the cables and sheaths of the present invention. These examples are not intended to limit the scope of the invention.

[0071] The materials used in the co-extrusion process were dried at 80 °C for 2–4 hours prior to extrusion. The outer and inner jackets were extruded at 190 °C–230 °C. The jacket thicknesses varied, and samples were taken for surface quality analysis, the VW-1 test, and weather resistance testing.

[0072] The following raw materials were used for the examples. Outer shell 1 MP-2979A from Teknor Apex Inner jacket 1 CE-23945D from Teknor Apex Inner jacket 2 CE-23950D from Teknor Apex Inner jacket 3 CE-12390 from Teknor Apex

[0073] The following test protocols were used for the tests. test Units Test procedure UL 94 VB test V-0 Pass / Fail UL 94 VW-1 flame test VW-1 Pass / Fail UL-1581, Section 1080 Weather resistance test DE, 150 KJ / m 2 SAEJ2412 Chemical resistance % change in tensile elongation / fracture Procedure described above, ASTM-D412 Relative density ASTM D792 Durometer hardness (5-s) Shore hardness ASTM D2240

[0074] The outer shell 1 It comprised a styrene block copolymer, polypropylene, an ethylene propylene copolymer, a plasticizer, and additives. The outer sheath 1 was free of flame retardants. The inner linings 1 , 2 and 3 Each contained a styrene block copolymer with a soft block with controlled distribution, including vinylalkenylarene units, polypropylene, and EVA. Flame retardants were phosphorus-containing flame retardants and melamine-containing flame retardants, including piperazine pyrophosphate and melamine pyrophosphate. Table 1 test Outer shell 1 Inner jacket 1 Inner jacket 2 Inner jacket 3 Relative density 0,91 1,2 1,21 1,22 Durometer hardness (5-s) 80A 45D 50D 47D UL 94 VB TEST Failed V-0 at 1.058 mm (1 / 24 in) V-0 at 1.058 mm (1 / 24 in) V-0 at 1.058 mm (1 / 24 in)

[0075] Table 1 shows the basic properties of the compositions used to form the outer and inner jackets. Each inner jacket achieved a V-0 rating at 1.058 mm (1 / 24 in) according to the UL 94 VB test. The outer jacket did not achieve the rating specified by UL 94. Table 2 Chemical resistance test Units Outer shell 1 % % Change Inner jacket 2 % % Change Inner jacket 3 % % Change No heat exposure Tensile strain (fracture) % 661 removed. 248 removed. 289 removed. Heat exposure conditions - 65 °C / 72 h Tensile strain (fracture) % 701,5 3,1 240 -3,2 266 -8,0 Chemical exposure conditions - 65 °C / 72 h skin oil Tensile strain (fracture) % 657,0 -6,3 303 26,3 305 14,7

[0076] Table 2 shows the tensile elongation values ​​for the tested coats 1 ) with and 2Without heat exposure, the sheath compositions were tested for chemical resistance and compared with the tensile elongation values ​​obtained from sheath compositions exposed to heat. Small percentage changes in tensile elongation are desirable. The data show that the outer sheath compositions exhibit chemical resistance far above average compared to the inner sheath compositions, as assessed by the change in tensile elongation to failure. The percentage tensile elongation results show that the inner sheath compositions swelled significantly after exposure to skin oils. This indicates a lack of chemical resistance. In comparison, no significant swelling was observed in the outer sheath composition. The outer sheath composition had seven percent lower values ​​for the change in tensile elongation to failure.Consequently, when used as an outer sheath in cable construction, a significantly improved overall chemical resistance is achieved compared to cables with FR compound sheathing. Table 3 Cable constructions Example Sample description % Thickness - Outer layer VW-1 result 1 Outer sheath 1 (0.05 mm), inner sheath 2 (0.53 mm) 9,1 Passed 2 Outer sheath 1 (0.043 mm), inner sheath 2 (0.71 mm) 5,7 Passed 3 Outer sheath 1 (0.06 mm), inner sheath 2 (0.75 mm) 7,3 Passed 4 Outer sheath 1 (0.06 mm), inner sheath 1 (0.69 mm) 8 Passed 5 Outer sheath 1 (0.045 mm), inner sheath 1 (0.78 mm) 5,4 Passed 6 Outer sheath 1 (0.046 mm), inner sheath 1 (0.51 mm) 8,3 Passed 7 Outer sheath 1 (0.054 mm), inner sheath 3 (0.545 mm) 9 Passed

[0077] Table 3 shows that all constructions with an outer layer without flame retardants achieved a VW-1 rating at various percentage thicknesses of the outer shell. Table 4 Weather resistance test Weather resistance test Outer shell 1 Inner jacket 1 Inner jacket 2 ΔE, 150 KJ / m 2 1,425 8,3 12,7

[0078] Table 4 shows the composition of the outer shell 1 exhibited far better weather resistance than the compositions of inner jackets 1 and inner mantle 2 Therefore, the color shift is far less than in the composition of the outer shell. 1and more desirable in terms of appearance for the end user. Similar results were obtained when testing the cables for their weather resistance. Cables without an outer FR layer showed very minimal color shift, whereas cables with an FR-TPE outer layer exhibited significant yellowing and stickiness.

[0079] To avoid any doubt, the present invention encompasses all possible combinations of the components, including various regions of the components disclosed herein. Furthermore, it is pointed out that the term "encompasses" does not exclude the presence of other elements. It is equally obvious that a description of a product or composition comprising certain components also discloses a product consisting of those components. Similarly, a description of a process comprising certain steps also discloses a process consisting of those steps.

[0080] While the best way of realization and the preferred embodiments have been set out in accordance with patent law, the scope of the invention is in no way limited to the scope of the setting out, but only to the scope of the accompanying claims. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 2014 / 0234620

[0004] US 2013 / 0306350

[0005] US 6178277

[0006] US 6031053

[0034] US 6197889

[0034] US 6653408

[0039] US 7169848

[0045] US 3595942

[0052] US 3634549

[0052] US 3670054

[0052] US 3700633

[0052] US 4578429

[0053] US 5506299

[0053] US 4882384

[0053] US 4898914

[0053] US 4970265

[0053] US 5206300

[0053] US 5276101

[0053] US 5516831

[0053] US 9156978

[0066]

Claims

[1] A cable with a flame-retardant covering comprising the following: a core containing at least one wire; an inner sheath surrounding the core, consisting of a thermoplastic elastomer and at least one flame retardant; and an outer sheath surrounding the inner sheath, which consists of a thermoplastic elastomer and is substantially free of flame retardants, wherein the cable passes the VW-1 flame test according to UL 1581, section 1080. [2] Cable according to claim 1, wherein the thermoplastic elastomer of the inner sheath comprises a styrene block copolymer, and wherein the thermoplastic elastomer of the outer sheath comprises a styrene block copolymer. [3] Cable according to claim 2, wherein at least one flame retardant is halogen-free. [4] Cable according to claim 1, wherein the outer sheath has a thickness of approximately 0.5 percent to approximately 30 percent, based on the total thickness of the inner sheath and the outer sheath. [5] Cable according to claim 2, wherein the composition used for the formation of the inner sheath passes the UL 94 VB test at a thickness of 3.175 mm (1 / 8 in) with a rating of V-0, and wherein the composition used for the formation of the outer sheath does not pass the UL 94 VB test at a thickness of less than or equal to 3.175 mm (1 / 8 in). [6] Cable according to claim 3, wherein the composition used for the formation of the outer sheath has a weather resistance of less than 8 AE, 150 kJ / m as measured according to SAE J2412. 2 exhibits. [7] A cable with a halogen-free flame-retardant sheath comprising the following: a core containing at least one wire; an inner sheath surrounding the core, consisting of a thermoplastic elastomer and at least one flame retardant; and an outer sheath surrounding the inner sheath, wherein the outer sheath comprises a thermoplastic elastomer and is substantially free of flame retardants, wherein the outer sheath has a weather resistance of less than 8 ΔE at 150 kJ / m as measured in accordance with SAE J2412 2 exhibits. [8] Cable according to claim 7, wherein the thermoplastic elastomer of the inner sheath comprises a styrene block copolymer, and wherein the thermoplastic elastomer of the outer sheath comprises a styrene block copolymer. [9] Cable according to claim 8, wherein at least one flame retardant is halogen-free. [10] Cable according to claim 9, wherein the outer sheath has a thickness of approximately 0.5 percent to approximately 30 percent, based on the total thickness of the inner sheath and the outer sheath. [11] Cable according to claim 10, wherein the composition used for the formation of the inner sheath passes the UL 94 VB test at a thickness of 3.175 mm (1 / 8 in) with a rating of V-0, and wherein the composition used for the formation of the outer sheath does not pass the UL 94 VB test at a thickness of less than or equal to 3.175 mm (1 / 8 in).

Images