US 2011 O168425A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2011/0168425A1 Basfar et al. (43) Pub. Date: Jul. 14, 2011

(54) CLEAN FLAME RETARDANT (52) U.S. Cl...... 174/110 SR: 524/563; 524/586: COMPOSITIONS WITH CARBON NANO 524/570; 524/574; 524/562; 524/496; 524/437; TUBE FOR ENHANCING MECHANICAL 524/436; 524/414; 524/424; 524/405; 524/406; PROPERTIES FOR INSULATION OF WIRE 525/55;977/742; 977/932 AND CABLE (76) Inventors: Ahmed Ali Basfar, (US); Hun Jai Bae, (US) (57) ABSTRACT (21) Appl. No.: 12/684,139 Commercial thermoplastic clean flame retardant materials in wire and cable insulation are mechanically unstable due to (22) Filed: Jan. 8, 2010 high filler loading. In the present invention, thermoplastic, black color, clean flame retardant composition using carbon Pl blication Classification nano tubes (CNT) is made. The resultant compositions pos (51) Int. Cl. sess very low smoke and toxicity. CNT with outer diameter of HOIB 7/295 (2006.01) 40-60 nm and length of under 20 Lum are used to increase COSL 3L/02 (2006.01) mechanical properties and flame retardancy. Thermo plasti C08L 23/06 (2006.01) cally extruded composition consists of each component by COSL 9/00 (2006.01) parts by weight as follows: 100 of resin (polyolefin or 100 of COSL 3.3/06 (2006.01) polyolefin/ethylene propylene diene monomer (EPDM)), C08K 3/04 (2006.01) 90-150 of non halogen containing flame retardants, 1-20 of C04B 26/06 (2006.01) auxiliary secondary flame retardantagents, 2-4 of CNT (outer CSK 3/22 (2006.01) diameter of 40-60 nm) and length under 20um and 0.2-1.0 of CSK 3/32 (2006.01) antioxidants. A reliable method for producing thermoplastic C08K 3/26 (2006.01) black color clean flame retardant insulation material for wire CSK 3/38 (2006.01) and cable without deterioration of mechanical properties is CSK 3/10 (2006.01) discussed.

X200,000 EDAX micrographs of CNTs. Patent Application Publication Jul. 14, 2011 Sheet 1 of 7 US 2011/O168425 A1

X200,000 Figure 1 EDAX micrographs of CNTs. Patent Application Publication Jul. 14, 2011 Sheet 2 of 7 US 2011/O168425 A1

25O : CNT50 -e-: CNT 75 -A-: CM-95 2OO O -v- : Carbon Black

150

O 2 4 CNT or Carbon Black content (phr)

Figure 2 Elongation at break of ethylene vinyl acetate (Evaflex 360)/120phr magnesium hydroxide (MAGNIFIN A Grades H10A) formulations as a function of CNT or carbon black content. Patent Application Publication Jul. 14, 2011 Sheet 3 of 7 US 2011/O168425 A1

: CNT50 : CNT75 CM-95 : Carbon Black

O 2 4 6 CNT or Carbon Black Content (phr)

Figure 3 Tensile strength of ethylene vinyl acetate (Evaflex 360)/120phr magnesium hydroxide (MAGNIFINA Grades H10A) formulations as a function of CNT or carbon black content. Patent Application Publication Jul. 14, 2011 Sheet 4 of 7 US 2011/O168425 A1

: CNT50 : CNT75 : CM-95 : Carbon Black

O 2 4 6 CNT or Carbon Black content(phr)

Figure 4 LOI (%) of ethylene vinyl acetate (Evaflex 360)/120phr magnesium hydroxide (MAGNIFIN A Grades H10A) formulations as a function of CNT or carbon black content. Patent Application Publication Jul. 14, 2011 Sheet 5 of 7 US 2011/O168425 A1

18O SS f; 160

s 5 140 O) O 120 -H: CNT50 -O-: Carbon Black 1OO O 2 4 6 CNT50 or Carbon Black Content (phr)

Figure 5 Elongation at break of ethylene vinyl acetate (Evaflex 360)/linear low density polyethylene (LLDPE 118W)/120phr magnesium hydroxide (MAGNIFIN A Grades H10A) formulations as a function of CNT 50 or carbon black content. Patent Application Publication Jul. 14, 2011 Sheet 6 of 7 US 2011/O168425 A1

18 -H: CNT50 111 24.6 -O-: Carbon Black

1 O

O 2 4 6 CNT50 or Carbon Black Content (phr)

Figure 6 Tensile strength of ethylene vinyl acetate (Evaflex 360)/linear low density polyethylene (LLDPE 118W)/120phr magnesium hydroxide (MAGNIFIN A Grades H10A) formulations as a function of CNT 50 or carbon black content. Patent Application Publication Jul. 14, 2011 Sheet 7 of 7 US 2011/O168425 A1

-H: CNT50 -O-: Carbon Black

O 2 4. 6 CNT50 or Carbon Black Content (phr) Figure 7 LOI of ethylene vinyl acetate (Evaflex 360)/linear low density polyethylene (LLDPE 118W)/120phr magnesium hydroxide (MAGNIFIN A Grades H10A) formulations as a function of CNT 50 or carbon black content. US 2011/O168425 A1 Jul. 14, 2011

CLEAN FLAME RETARDANT tion time. Enhanced cable insulations must also meet IEC COMPOSITIONS WITH CARBON NANO 60502, BS 6724 and BS 7655 standards specific for thermo TUBE FOR ENHANCING MECHANICAL plastic compound requirements. PROPERTIES FOR INSULATION OF WIRE 0007 EVA(ethylene vinyl acetate), EVA/LDPE (low den AND CABLE sity polyethylene)(or LLDPE (linear LDPE), ethylene alpha olefin or ethylene ethyl acrylate are widely used as matrix FIELD OF INVENTION polymer because of their high flame retardant loadability and increased flame retardancy. Main flame retardants mostly 0001. This disclosure generally relates to non toxic, halo comprise of inorganic materials, such as, aluminum trihy gen free thermoplastic flame retardant composition contain droixide (ATH), magnesium hydroxide (MH) and huntite ing carbon nano tube (CNT) as insulating material for wire hydromagnesite (HH). They exhibit high decomposition tem and cable. More particularly, this invention relates to clean perature and have the ability to Suppress Smokeas clean flame flame retardant compositions for increasing flame retardancy retardant materials. However, more than 50% w/w loading is without deterioration of mechanical properties. required to achieve the target flame retardancy. Unfortu nately, such high contents of flame retardants can lead to BACKGROUND interfacial problems between matrix polymer and flame retar 0002 Every year, the world faces huge losses in lives and dants and then, can negatively affect the mechanical proper property due to residential and commercial fires caused by, ties. electrical wiring. Human lives can be lost due to high tem 0008 Various studies were performed to improve perature flames, toxic Smoke and gas that are generated from mechanical properties and flame retardancy by using organic the flammable insulation materials used in wire and cable encapsulated flame retardants (Chang et al. 2006, Du Let al. during fire. 2006, Liu Yet al. 2006), and synergistic effect of hydrotalcite 0003. The current population uses many equipments and with two flame retardants and organo-modified montmorillo gadgets that contain several wires and cables. Most wires and nite (Laoutid Fet al. 2006, Ma Hetal. 2006). cables are fabricated from plastic materials that are readily 0009 Organic encapsulated flame retardants can enhance flammable. Moreover, modern living involves heavy use of the interfacial adhesion with matrix polymers and lead to electric equipment containing wires and communication sys improved dispersion compared to non-encapsulated flame tems made of cables. These conditions further increase the retardants. Hydrotalcite composites increase flame retar loss of lives and properties due to bad insulation of a wire or dancy by releasing more gas compared to other flame retar a cable resulting in an electrical fire. Smoke and toxic fumes dants during burning. In addition, partial Substitution of flame from poor insulation materials in wires and cables can cause retardants by organo-modified montmorillonite improves the irreparable health damage. burning properties. All these result only in improved flame 0004 Wire and cable insulations are required to meet not retardancy. only the electrical properties but also the mechanical proper 0010 Specification standards for wire and cable insulation ties. Polyethylene and polyvinylchloride compounds are composition require high flame retardancy and Superior some of the best materials suitable for wire and cable insula mechanical properties. For example, the minimum required tions because of their excellent electrical and mechanical tensile strength is 8.8 MPa and minimum elongation at break properties. However, these materials have poor flame retar is 125% based on IEC 60502, BS 6724 and BS 7655 standards dancy and generate toxic gases during a fire. for thermoplastic compounds. Moreover, additional treat 0005 Polyethylene, for example, is easily flammable and ment of flame retardants or mixing with special chemicals generates less toxic gases during the burning process. On the increase cost performance of final products. There is a need to other hand, Polyvinylchloride compounds generate a lot of obtain a wire and cable insulation material that contains a toxic gases during a fire, even though it has acceptable flame clean flame retardant material, has Superior mechanical prop retardancy. Currently, clean flame retardant materials are erties and high flame retardancy. Without meeting these made from special formulations. These special formulations important properties, the clean flame retardant materials are are made of halogen and toxicity free chemicals. Clean flame not suitable for wire and cable insulation purposes. retardant materials mainly consist of matrix polymers that do not contain halogen, main flame retardants, secondary flame SUMMARY retardants, intumescent flame retardants, processing aids and antioxidants. (Mans Vetal. 1998, Rai Metal. 1998, Wei Pet 0011. The current invention is carried out to find a flame al. 2006 and Luciana Retal. 2005). The resultant mixture has retardant material which does not generate toxic gases for very poor mechanical properties. wire and cable insulation materials during a fire. The flame 0006. The other biggest problem with commercially clean retardant materials are known as halogen free flame retardant material is that they have unstable mechanical properties, compounds (HFFR compounds), clean flame retardant mate even though they possess high flame retardancy, due to high rials and/or non toxic flame retardant materials. filler loadings. Clean flame retardant materials contain rela 0012. The current invention relates to thermoplastic (not tively high content of inorganic materials as flame retardants. thermosetting) type clean flame retardant materials for wire In general, high levels of flame retardants are necessary to and cable. The current invention pertains to unique formula achieve commercially acceptable flame retardancy levels for tions and processing methods of clean flame retardant mate wires and cables. However, high levels of flame retardants rials of wire and cable. Partially crosslinkable clean flame may lead to deterioration of mechanical properties. Insulation retardant compositions, which can be partially crosslinked by and jacket materials for wire and cable should meet appro routine thermoplastic extruder without using post curing sys priate standards for tensile strength, elongation at break, ther tems, are described. The current invention of clean flame mal resistance and flame retardancy for an extended applica retardant compositions are particularly Suitable for use in US 2011/O168425 A1 Jul. 14, 2011

enhanced cable insulations to meet the requirement of ther DPE 118W)/120 phr magnesium hydroxide (MAGNIFINA moplastic compound standards. Grades H10A) formulations as a function of CNT 50 or 0013. In general, polymer parts in clean flame retardant carbon black content. compositions are under 50% by weight and flame retardants (0022 FIG. 7 illustrates LOI of ethylene vinyl acetate parts are over 50% by weight. Moreover, the particle size of (Evaflex 360)/linear low density polyethylene (LLDPE most flame retardants used in clean flame retardant materials 118W)/120 phr magnesium hydroxide (MAGNIFIN A is under 50 lum, which enables excellent dispersion of poly Grades H10A) formulations as a function of CNT 50 or mer/flame retardants/Carbon NanoTube (CNT) in the com carbon black content. position. Therefore, at first, three different types of multi walled CNT with different diameter range for e.g. 10-15 nm, DETAILED DESCRIPTION OF THE FIGURES 40-60 nm and 60-80 nm are investigated to establish better 0023 FIG. 1 shows CNT with different diameter sizes and compatibility with the other materials in thermoplastic clean tube lengths are investigated to find compatibility with the flame retardant compositions. It was found that CNT with other components in thermoplastic clean flame retardant outer diameter of 40-60 nm and length distribution under 20 compositions. CM-95 (Hanwha nanotech/Korea, multi um may show improved results in terms of mechanical prop walled CNT synthesized by catalytic CVD process, diameter erties and flame retardancy. Hence, CNT can be used in range: 10-15 nm), CNT 50 (NanoKarbon, Korea nano Ind. thermoplastic clean flame retardant compositions instead of Co., multi-walled CNT synthesized by catalytic CVD pro carbon black to improve mechanical properties and flame cess, inner diameter: 10-30 nm, outer diameter: 40-60 nm, retardancy. length distribution: under 20 um) and CNT 75 (NanoKarbon, 0014. The instant composition is processed by routine Korea nano Ind. Co., multi-walled carbon nanotubes synthe thermoplastic extruder and may show improved mechanical sized by catalytic CVD process, inner diameter: 30-50 nm, properties and flame retardancy. Composition mainly com outer diameter: 60-80 nm, length distribution: under 20 um) prises of 100 parts by weight of resin (polyolefin or 100 parts are investigated for finding better compatibility with the other by weight of polyolefin/ethylene propylene diene monomer components. (EPDM)), 90-150 parts by weight of non halogen content 0024. As preliminary test, a comparison between CNT main flame retardants, 1-20 parts by weight of auxiliary sec and carbon black in EVA/MAGNIFINA Grades H10A for ondary flame retardant agents, 2-4 parts by weight with CNT mulations is conducted as shown in FIGS. 2, 3 and 4. Elon of outer diameter of 40-60 nm and length distribution of under gation at break (%) of EVA/120 phr H10A formulations as a 20 um and 0.2-1.0 parts by weight of antioxidants. The function of CNT or carbon black content is shown in FIG. 2. present invention demonstrates a reliable method of produc Apparently different trends are observed from different CNTs ing black color clean flame retardant insulation material for even the content is quite Small. At the range of up to 4 phr wires and cables. The said composition also possess a high content, elongation at break decreases with increase of CNT flame retardancy and meets the specification standard for content. CM-95 shows the lowest elongation at break even mechanical properties as an insulation material for wires and compared to carbon black. It is considered that the mechani cables. cal properties depend on the size of particle. When only CNT50/CNT75 formulations and CB contained formulations BRIEF DESCRIPTION OF THE FIGURES are compared in elongation at break, it is apparent that CNT50/CNT75 formulations show higher values than CB 00.15 Example embodiments are illustrated by way of contained formulations. From the results, it is considered that example and not limitation in the figures of accompanying CNT50/CNT75 can be used in HFFR formulations instead of drawings. CB for obtaining higher elongation at break values. 0016 FIG. 1 illustrates EDAX micrographs of CNTs that (0025 Tensile strength of EVA/120 phr H10A formula are taken by EDAX system, Model NNL200 from FEI Com tions as a function of CNT or CB content is shown in FIG. 3. pany, Netherlands. Apparently different trends are observed from different CNTs 0017 FIG. 2 illustrates elongation at break of ethylene even at Small contents. At the range of up to 6 phr content, vinyl acetate (Evaflex 360)/120 phr magnesium hydroxide tensile strength increases with increase of CNT content. (MAGNIFINA Grades H10A) formulations as a function of CM-95 shows the highest tensile strength even compared to CNT or carbon black content. CB contained formulations. It is proposed that smaller size of particles shows higher tensile strength, therefore, CM-95 0018 FIG. 3 illustrates tensile strength of ethylene vinyl shows the highest tensile strength and CB shows the lowest acetate (Evaflex 360)/120 phr magnesium hydroxide (MAG tensile strength. When only CNT50/CNT75 formulations and NIFINA Grades H10A) formulations as a function of CNT or CB contained formulation are compared in terms of tensile carbon black content. strength, it is found that CNT50/CNT75 formulations show 0019 FIG. 4 illustrates LOI (%) of ethylene vinyl acetate much higher values than CB contained formulations. (Evaflex 360)/120 phr magnesium hydroxide (MAGNIFINA 0026. From the results of FIGS. 2 and 3, it is apparent that Grades H10A) formulations as a function of CNT or carbon CNT50/CNT75 formulations show higher values than CB black content. contained formulations in both mechanical properties (elon 0020 FIG. 5 illustrates elongation at break of ethylene gation at break and tensile strength). Therefore, it is consid vinyl acetate (Evaflex 360)/linear low density polyethylene ered that CNT50/CNT75 can be used in HFFR formulations (LLDPE 118W)/120 phr magnesium hydroxide (MAGNI instead of CB for obtaining higher mechanical properties FINA Grades H10A) formulations as a function of CNT 50 or (elongation at break and tensile strength). carbon black content. (0027 LOI (%) of EVA/120 phr H10A formulations as a 0021 FIG. 6 illustrates tensile strength of ethylene vinyl function of CNT or CB content is shown in FIG. 4. CNT507 acetate (Evaflex 360)/linear low density polyethylene (LL CNT75 and carbon black formulations show almost similar US 2011/O168425 A1 Jul. 14, 2011

flame retardancy. Flame retardancy increases with increase of weight, 2-20 parts intumescent flame retardant such as red content in CNT50, CNT75 and CB contained formulations. phosphorus, zinc borate, and boric acid by weight, 0.5-1.5 0028. From the results of FIGS. 2, 3 and 4, it is apparent parts antioxidant by weight. Based on particular application, that CNT50/CNT75 formulations show higher mechanical additional coloring agent, weathering protection agent, pro properties without losing flame retardancy compared with cessing aid, coupling agent, lubricant and thermal stabilizer CB contained formulations. Therefore, CNT50/CNT75 can may be added to the composition. be used in HFFR formulations instead of CB for obtaining 0035. The polymer may be (by weight) under 50% of total higher mechanical properties (elongation at break and tensile compound in a clean flame retardant composition. In addi strength) and flame retardancy. tion, the particle size of most flame retardants which are used 0029. For reconfirming the results of FIGS. 2, 3 and 4, the in clean flame retardant compositions may be under 50 Lum. relationships between CNT50 and CB in EVA/LLDPE/ The aforementioned particle size of the flame retardant exhib MAGNIFIN A Grades H10A are investigated as shown in its better dispersion properties to obtain better mechanical FIGS.5, 6 and 7. LLDPE (20% weight content) is mixed with properties. When the polymer and the flame retardants are EVA to increase thermal properties. Elongation at break (%) mixed well in the compounding process results in a balanced of Evaflex 360/LLDPE 118W/120 phr H10A formulations as arrangement of polymer and flame retardant to obtain better a function of CNT 50 or CB is shown in FIG. 5. It is appar mechanical properties. ently observed that CNT50 contained formulations show 0036. This invention pertains to special formulations with higher elongation at break values compared with CB con unique materials of clean flame retardant materials for wire tained formulations. Elongation at break slightly increases and cable. The present invention leads to improved flame with increase of CNT50 content while elongation at break retardancy and mechanical properties, particularly maintain slightly decreases with increase of CB content. ing elongation at break/tensile strength without deteriorating 0030 Tensile strength of Evaflex 360/LLDPE 118W/120 flame retardancy in black color thermoplastic type clean phr H10A formulations as a function of CNT50 or CB content flame retardant compositions. is shown in FIG. 6. It is apparently observed that CNT50 0037 More particularly, this invention relates to formula contained formulations show higher tensile strength values tions of black color thermoplastic clean flame retardant com compared with CB contained formulations. Tensile strength positions which do not contain carbon black. As shown in increases with increase of CNT50 or CB. However, rate of Conventional examples, it is known that carbon black can increase of CNT50 contained formulations is higher than that increase flame retardancy however it may decreased of CB contained formulations. For both mechanical proper mechanical properties specially elongation break in black ties, higher values are obtained by CNT50 compared with color thermoplastic clean flame retardant compositions com CB. pared to the present invention. The current composition may 0031 LOI (%) of Evaflex 360/LLDPE 118 W/120 phr pass V-0 of UL94 test with satisfactory mechanical properties H10A formulations as a function of CNT or CB content is of minimum tensile strength 8.8 MPa and minimum elonga shown in FIG. 4. Higher flame retardancy is observed by tion at break 125% based on IEC 60502 standards compared CNT50 contained formulations compared with CB contained to Conventional examples. formulations. Flame retardancy increases with increase of 0038 Moreover, in most commercial situations, mechani CNT50 or CB content. However, the rate of increase for cal properties are always fluctuating after production of wire CNT50 contained formulations is higher than that of CB and cable. The extruding temperature can be changed by contained formulations. The highest LOI is observed at 4 phr seasonal environmental conditions, speed and cable size are CNT50 contained formulations. also changed by various specifications and client's demand. Therefore, mechanical properties of clean flame retardant DETAILED DESCRIPTION compositions should show at least 20-30% higher than nor 0032. There are two types of clean flame retardant mate mal specification values. When the mechanical properties just rials for wire and cable, i.e., thermoplastic (without cross meet the specification values, the quality control margin is linking) and thermosetting (cross-linked). This invention very tight, accordingly, Some products may fail specifica relates to thermoplastic type clean flame retardant material tions. for wire and cable. More particularly, this invention relates to 0039. The main points for selecting the new material in black color thermoplastic clean flame retardant compositions this invention are as follows: for improving mechanical properties and flame retardancy. 0040. The new material which can be used instead of The invented clean flame retardant compositions may be par carbon black to increase flame retardancy in thermoplas ticularly suitable for use in enhanced cable insulations meet tic clean flame retardant compositions. ing IEC 60502, BS 6724 and BS 7655 standards for thermo 0041. This material may exhibit an increase in mechani plastic compounds requirements. cal properties, specially, elongation at break. 0033. This invention pertains to unique formulation and 0042. This material must be compatible with the other processing method of clean flame retardant material for wire flame retardant composition components. and cable. The present invention may lead to improved 0043 Carbon nano tubes (CNT) is very compatible for mechanical properties, particularly tensile strength and elon this purpose. Other flame reartdant compositions that are gation break without deteriorating flame retardancy. compatible with CNT are magnesium hydroxide, huntite 0034 Clean flame retardant compositions consist of 100 hydromagnesite, aluminum hydroxide, Zinc borate, carbon parts polymer (EVA (Ethylene VinylAcetate), EVA/polyeth black and etc. These components have very fine structure and ylene, EEA (Ethylene Ethyl Acrylate)/polyethylene or Eth are useful in flame retardant composition. ylene Alpha Olefin/polyethylene) by weight and 100-150 0044 CNT is considered as allotrope of carbon with nano parts inorganic flame retardant such as magnesium hydrox structure whose length-to-diameter ratio is very long. These ide, aluminum hydroxide and huntite hydromagnesite by cylindrical carbon molecules have novel properties which US 2011/O168425 A1 Jul. 14, 2011

make them potentially useful in many applications. It is Sug outer diameter 60-80 nm, length distribution: under 20 um) gested that allotropes may contribute to increase in flame are investigated for finding better compatibility with the other retardancy in clean flame retardant compositions; neverthe components. less, mechanical properties of compositions are not deterio 0046. The following are an example of Conventional for mulations that show results of clean flame retardant compo rated because CNT is constructed by nanostructure. This is sitions in terms of mechanical properties and flame retar the main reason to use CNT instead of carbon black in clean dancy. flame retardant composition in the current invention. 0047. As shown in examples, three different types offlame 0045. Several different types of CNT are investigated to retardants are investigated, such as MAGNIFIN A Grades find best compatibility with the other components in thermo H10A (magnesium hydroxide, formula: Mg(OH) producer: plastic clean flame retardant compositions. CNT is catego Albemarle? France), Ultracarb LH 15X(huntite hydromagne rized as single walled nanotube (SWNT), multi-walled nano site, formula: Mg, Ca(CO), Mgs (CO)4(OH)3H2O, pro ducer: Minelco/USA) and KISUMA5B (magnesium hydrox tube (MWNT), fullerene structural, spherical buckyball type ide, formula: Mg(OH), Producer: Kyowa Chemical/Japan). structural, different diameter sizes and tube lengths. In this Evaflex 360 (ethylene vinyl acetate, producer: DuPont-Mit invention, three multi-walled CNTs with different diameter sui Polychemicals Co./Japan, vinyl acetate content: 25%, sizes and tube lengths are investigated to find compatibility melt mass-flow rate (MFR) (190° C/2.16 kg): 2.0 g/10 min) with the other components in thermoplastic clean flame retar and LLDPE 118 (melt flow index: 1.0 g/10 min, producer: dant compositions. CM-95 (Hanwha nanotech/Korea, multi SABIC/Saudi Arabia) are used as base polymers. Irganox walled CNT synthesized by catalytic CVD process, diameter 1010 (chemical name: pentaerythritol tetrakis(3(3,5-di tert range: 10-15 nm), CNT 50 (NanoKarbon, Korea nano Ind. buty-4-hydroxyphenyl)propionate, CIBA Specialty chemi Co., multi-walled CNT synthesized by catalytic CVD pro cals/Switzerland, melting range 110-125°C.) is used as anti cess, inner diameter: 10-30 nm, outer diameter: 40-60 nm, oxidant. Corax N550 (producer: Degussa, Germany, semi length distribution: under 20 um) and CNT 75 (NanoKarbon, active carbon black with high structure, ash content: 0.5%) is Korea nano Ind. Co., multi-walled carbon nanotubes synthe used as carbon black. All materials of experimental are sum sized by catalytic CVD process, inner diameter: 30-50 nm, marized in Table 1.

TABLE 1

Materials list.

Function? Chemical Name Material Producer Characteristics Polymer, ethylene vinyl Evaflex 360 DuPont-MitSui vinyl acetate acetate (EVA) Polychemicals content: 25%, Co., Japan melt mass-flow rate (MFR) (190° C./2.16 kg): 2.0 g/10 min) Polymer, linear low LLDPE 118 SABIC Saudi Arabia melt flow index: density polyethylene 1.0 g 10 min (LLDPE) Flame retardant, MAGNIFIN Albemarle? France magnesium hydroxide, A Grades ormula: Mg(OH), H10A Flame retardant, huntite Ultracarb Minelco, USA hydromagnesite, formula: LH 15X Mg3Ca(CO3)4, Mgs (CO3)4(OH)2.3H2O Flame retardant, KISUMA Kyowa Chemical Japan magnesium hydroxide, 5B ormula: Mg(OH)2 Antioxidant, pentaerythritol Irganox CIBA specialty melting range: etrakis(3(3,5-di tert-buty-4- 1010 chemicals, Switzerland 110-125° C. hydroxyphenyl)propionate, Carbon black Corax N550 Degussa Germany semi-active carbon black with high structure, ash content: 0.5% Intumescent flame Exoit RP Clariant France phosphorus retardants, red phosphorus 692 content: approx. masterbatch 50% (w.fw) Intumescent flame Firebrake Borax, USA retardants, Zinc borate ZB Intumescent flame Boric Acid Rose Mill Chemicals & retardants, Boric Acid Lubricant USA Carbon nano tube CM-95 Hanwha multi-walled CNT nanotech Korea synthesized by catalytic CVD process, diameter ranges: 10-15 nm. US 2011/O168425 A1 Jul. 14, 2011

TABLE 1-continued

Materials list.

Function? Chemical Name Material Producer Characteristics Carbon nano tube CNT 50 NanoKarbon, Korea multi-walled CNT nano Ind. Co. synthesized by catalytic CVD process, inner diameter: 10-30 nm, Outer diameter: 40-60 nm, length distribution: under 20 m Carbon nano tube CNT 75 NanoKarbon, Korea multi-walled CNT nano Ind. Co. synthesized by catalytic CVD process, inner diameter:30-50 nm, Outer diameter: 60-80 nm, length distribution: under 20 m

0048. The reason for using LDPE (or LLDPE) in base polymers is to increase thermal properties of thermoplastic TABLE 2 clean flame retardant compositions. In general, high filler mixable polymers, such as ethylene vinyl acetate (EVA), Standard Classification of material based ethylene ethyl acrylate (EEA) or ethylene alpha olefin have on their orientation and thickness very low softening temperatures. Mostly, their softening Standard points are under 100° C. Therefore, it is apparent that using Classification Description Conditions allowed only low softening temperature grade polymers without any HB Slow burning on a horizontal high temperature grade polymers in base polymers will lead specimen; burning rate <76 to loss in thermal properties. The thermal aging test condition mm/min for thickness <3 mm of thermoplastic clean flame retardant material is 100° C. for V2 Burning stops within 30 seconds Drips of flaming on a vertical specimen particles are allowed 136 hours. To achieve appropriate thermal stability, the mix V1 Burning stops within 30 seconds No drips allowed ing of high temperature grade polymer Such as polyethylene on a vertical specimen is required. Therefore, the base polymers in thermoplastic VO Burning stops within 10 seconds No drips allowed clean flame retardant compositions should have appropriate on a vertical specimen thermal stability to pass the thermal aging test (at 100° C. for 136 hours). However, polyethylene has low filler mix ability and lower flame retardancy, accordingly, ethylene vinyl acetate/polyethylene compounded base polymers can mix CONVENTIONALEXAMPLE1 less Volume offlame retardants and decrease flame retardancy compared to 100% ethylene vinyl acetate base polymer. 0050 0049 Mechanical properties (tensile strength and elonga tion at break) were measured using a universal testing machine Model 5543 from Instron, USA in accordance with Content Property C-1 C-2 C-3 C-4 C-5 ASTM D 638M with testing conditions: speed of 500 Ethylene vinyl acetate 8O 8O 8O 8O 8O mm/minute at 25° C. LOI (Limiting Oxygen Index) is a (Evaflex 360) simple method to evaluate the flame retardancy of the mate Linear low density 2O 2O 2O 2O 2O rials. LOI was performed using an apparatus of Fire Testing polyethylene (LLDPE Technology limited (Incorporating Stanton Redcroft), UK in accordance with ISO 4589 and ASTM D2863. LOI corre Magnesium hydroxide 120 120 120 120 120 (MAGNIFINA Grades sponds to the minimum percentage of oxygen needed for the H10A) combustion of specimens (80x10x1 mm) in an oxygen-nitro Carbon black (Corax N550) O 2 4 6 8 Pentaerythritol 1 1 1 1 1 gen atmosphere. The other method to estimate the flame etrakis(3(3,5-di tert-buty retardancy of the materials is UL 94 Flammability standard 4-hydroxyphenyl)propionate by Underwriters Laboratories, USA. UL 94 test was per (Irganox1010) formed using a flammability chamber of CEAST Co., Italy, in Tensile strength (MPa) 9 9 9.5 9.5 10 accordance with ASTM D 635 for horizontal and ASTM D Elongation at break (%) 16S 150 150 150 145 3801 for vertical test positions. The standard classifies plas LOI (%) 31 33 34 37 39 tics according to how they burn in various orientations and UL 94 test H-B H-B H-B H-B H-B thicknesses. From lowest (least flame-retardant) to highest (most flame-retardant), the classifications are shown in Table 0051. These formulations are basic thermoplastic clean 2: flame retardant compositions which consist of one main US 2011/O168425 A1 Jul. 14, 2011 flame retardant (magnesium hydroxide (MAGNIFIN A elongation at break is quite prominent. Elongation at break Grades H10A)) with various contents of carbon black (Corax decreases with increase of carbon content. Normally, increase N550). From the experimental results, it is found that elon of filler content may cause decrease in mechanical properties. gationatbreak decreases slightly even thoughtensile strength Carbon black plays the role of filler in compounds; however and flame retardancy increase with increase of carbon black under 8 phr of carbon black content by weight, the tensile (Corax N550) content. strength remains almost constant while elongation at break is greatly influenced. In addition, it is apparent that LOI (%) CONVENTIONALEXAMPLE 2 increases with increase of carbon black content. From our experimental, it is definite that carbon black increases flame 0052 retardancy and decreases elongation at break in black color thermoplastic clean flame retardant compositions. 0056. In Conventional examples 1, 2 and 3, no composi Content Property C-6 C-7 C-8 C-9 C-10 tion passes V-0 of UL 94 test with satisfactory mechanical properties of minimum tensile strength 8.8 MPa and mini Ethylene vinyl acetate 8O 8O 8O 8O 8O mum elongation at break 125% based on IEC 60502 stan (Evaflex 360) Linear low density 2O 2O 2O 2O 2O dards. To pass V-0 of UL94 test, higher than 120 phr content polyethylene (LLDPE of main flame retardant with secondary (intumescent) flame 18W) retardants such as red phosphorus, Zinc borate, and (or) boric Huntite 120 120 120 120 120 acid has to be compounded. However, additional main and hydromagnesite intumescent flame retardants can cause deterioration of (Ultracarb LH 15X) Carbon black (Corax N550) O 2 4 6 8 mechanical properties in spite of improvement inflame retar Pentaerythritol 1 1 1 1 1 dancy as shown in Conventional example 4. Exolit RP 692 etrakis(3(3,5-di tert-buty 4-hydroxyphenyl)propionate (red phosphorus master batch, producer: Clariant/France, (Irganox1010) phosphorus content: approx. 50% (w/w)), Firebrake ZB (Zinc Tensile strength (MPa) 7 7 8 9 9 borate, producer: Borax/USA) and Boric Acid (Producer: Elongation at break (%) 160 145 140 130 130 Rose Mill Chemicals & Lubricant/USA) are used as intumes LOI (%) 27 32 34 35 37 cent flame retardants. Formulations of C-17 to C-20 which UL 94 test H-B H-B H-B H-B H-B contain carbon black show big drop in elongation at break in spite of high LOI values. Many scientists are eager to find a 0053 Similar to Conventional Example 1, these formula substitute material for carbon black, which does not deterio tions are also basic thermoplastic clean flame retardant com rate mechanical properties with improved flame retardancy in positions with various contents of carbon black (Corax thermoplastic clean flame retardant compositions. In our N550), and the main flame retardant is changed from magne invention, new material which can substitute carbon black in sium hydroxide (MAGNIFIN A Grades H10A) to huntite thermoplastic clean flame retardant compositions for this par hydromagnesite (Ultracarb LH 15X). From the experimental ticular purpose is introduced. results, similar tendency is observed, i.e. it is found that elongation at break decreases slightly even though tensile CONVENTIONALEXAMPLE 4 strength and flame retardancy increase with increase of car bon black (Corax N550) content. 0.057 CONVENTIONALEXAMPLE 3 0054 Content Property C-16 C-17 C-18 C-19 C-2O Ethylene vinyl acetate 8O 8O 8O 8O 8O (Evaflex 360) Linear low density 2O 2O 2O 2O 2O Content Property C-11 C-12 C-13 C-14 C-15 polyethylene (LLDPE 18W) Ethylene vinyl acetate 8O 8O 8O 8O 8O Magnesium hydroxide 130 130 130 130 130 (Evaflex 360) (MAGNIFINA Grades Linear low density 2O 2O 2O 2O 2O H10A) polyethylene (LLDPE Red Phosphorus 5 5 5 5 5 18W) (RP-692) Magnesium hydroxide 120 120 120 120 120 Zinc Borate 5 5 5 5 5 (KISUMASB) (Firebrake ZB) Carbon black (Corax N550) O 2 4 6 Boric Acid 2 2 2 2 2 Pentaerythritol 1 1 1 1 1 Carbon black (Corax N550) O 2 4 6 8 etrakis(3(3,5-di tert-buty Pentaerythritol 1 1 1 1 1 4-hydroxyphenyl)propionate etrakis(3(3,5-di tert-buty (Irganox1010) 4-hydroxyphenyl)propionate Tensile strength (MPa) 10 9.5 9.5 9.5 9.5 (Irganox1010) Elongation at break (%) 550 500 480 450 420 Tensile strength (MPa) 10 9.5 10 10 10 LOI (%) 27 31 32 32 35 Elongation at break (%) 1SO 130 115 105 1OO UL 94 test H-B H-B H-B H-B H-B LOI (%) 34 35 37 38 40 UL 94 test W-O W-O W-O W-O W-O 0055 As shown in Conventional example 3, not much change intensile strength is observed with increase of carbon 0058. In the current invention, clean flame retardant com black content. On the contrary, influence of carbon black on positions consist of 100 parts polymer (EVA (Ethylene Vinyl US 2011/O168425 A1 Jul. 14, 2011

Acetate), EVA/polyethylene, EEA (Ethylene Ethyl Acrylate)/ examples, only Evaflex 360 is used as base matrix polymer. polyethylene or Ethylene Alpha Olefin/polyethylene) by The relationships between elongation at break/CNT (or car weight and 100-150 parts inorganic flame retardants such as bon black content), tensile strength/CNT (or carbon black magnesium hydroxide, aluminum hydroxide and huntite content) and flame retardancy/CNT (or carbon black content) hydromagnesite by weight, 2-20 parts intumescent flame are shown in FIGS. 2-4. retardants such as red phosphorus, Zinc borate, and boric acid by weight, 0.5-1.5 parts antioxidants by weight. Based on PRE-TEST EXAMPLE 1. particular application, additional coloring agent, weathering protection agent, processing aid, coupling agent, lubricant 0066 and thermal stabilizer are added to the compositions. 0059. In the current invention the polymer portion (by weight) is under 50% total compound in clean flame retardant compositions. In addition, the particle size of most flame Content Property P-1 P-2 P-3 P-4 retardants which are used in clean flame retardant composi Ethylene vinyl acetate 100 1OO 100 1OO tions are under 50 um. Excellent dispersion of polymer/flame (Evaflex 360) retardants is very important to obtain better mechanical prop Magnesium hydroxide 120 120 120 120 erties. When polymer/flame retardants are well mixed in (MAGNIFINA Grades H10A) compounding process, it is assumed that the arrangement of Carbon black (Corax N550) O 2 4 6 polymer and flame retardants is very well balanced. The Pentaerythritol 1 1 1 1 invention specially takes several aspects of improvements tetrakis(3(3,5-di tert-buty 4-hydroxyphenyl)propionate into consideration, Such as improving mechanical property (Irganox1010) and arrangement of polymers containing flame retardants in a Tensile strength (MPa) 10 9.3 9.5 10.8 highly filled composition. Elongation at break(%) 200 175 150 18O 0060. The current invention pertains to special formula LOI (%) 33 35 36.5 39 tions with unique materials of clean flame retardant materials for wire and cable. The present invention leads to improved flame retardancy and mechanical properties, particularly maintaining elongationatbreak/tensile strength without dete PRE-TEST EXAMPLE 2 riorating flame retardancy in black color thermoplastic type O067 clean flame retardant compositions. 0061 More particularly, this invention relates to formula tions of black color thermoplastic clean flame retardant com positions which do not contain carbon black which is gener Content Property P-5 P-6 P-7 P-8 ally used in ordinary black color clean flame retardant Ethylene vinyl acetate 100 100 100 1OO compositions at present. As shown in Conventional example (Evaflex 360) 1, 2, and 3, it is known that carbon black can increase flame Magnesium hydroxide 120 120 120 120 retardancy howeverit deteriorates mechanical properties spe (MAGNIFINA Grades H10A) cially elongation at break in black color thermoplastic clean CM-95 O 2 4 6 flame retardant compositions. Therefore, it is very difficult to (Outer D. = 10-15 nm) obtain satisfactory compositions which meet both main prop Irganox 1010 1 1 1 1 erty standrads such as flame retardancy and mechanical prop Tensile strength (MPa) 10.3 11.6 12.0 12.7 erties. It is hard to obtain suitable formulations which pass Elongation at break(%) 200 16S 133 135 V-0 of UL 94 test with satisfactory mechanical properties of LOI (%) 33 31.5 31.5 31.5 minimum tensile strength 8.8 MPa and minimum elongation at break 125% based on IEC 60502 standards in Conventional examples 1, 2 and 3. PRE-TEST EXAMPLE 3 0062 Moreover, in most commercial situations, mechani cal properties are always fluctuating after production of wire 0068 and cable. The extruding temperature, speed and cable size varies depending on environmental conditions, client require ments and standard specifications. Therefore, mechanical properties of clean flame retardant compositions should show Content Property P-9 P-10 P-11 P-12 at least 20-30% higher than normal specification values in Ethylene vinyl acetate 100 1OO 100 100 (Evaflex 360) order to pass the stringent quality control tests. Magnesium hydroxide 120 120 120 120 0063. In our invention, for solving deterioration of (MAGNIFINA Grades mechanical properties while maintaining high flame retar H10A) dancy in black colorthermoplastic clean flame retardant com Carbon nano tube (CNT50) O 2 4 6 (Outer D = 40-60 nm) positions, new material is introduced instead of carbon black. Pentaerythritol tetrakis(3(3,5-di tert- 1 1 1 1 0064. As shown in FIG. 1, it is observed that CM-95 has buty-4-hydroxyphenyl)propionate : much smaller diameter size and much higher length-to-diam (Irganox1010) Tensile strength (MPa) 10.3 11.3 11.5 12.0 eter ratio compared to CNT 50 and CNT 75. Elongation at break(%) 200 2OO 18O 18S 0065. As preliminary test, the relationships between LOI (%) 33 34.5 36.5 4.O.S MAGNIFIN A Grades H10A and CNT/carbon black are investigated as shown in pre-test examples. In pre-test US 2011/O168425 A1 Jul. 14, 2011

PRE-TEST EXAMPLE 4 (0071. As shown in FIG. 4, CNT50, CNT75 and carbon black formulations show almost similar trends of flame retar 0069 dancy as a function of content, on the contrary, CM-95 for mulation shows very low flame retardancy. Flame retardancy increases with increase of content in CNT50, CNT75 and carbon black formulations. Flame retardancy increases with Content Property P-13 P-14 P-15 P-16 as low as 2 phr of CNT50, CNT75 or carbon blackby weight. Ethylene vinyl acetate 1OO 100 100 1OO It is observed that these materials have strong influence on (Evaflex 360) flame retardancy in combination with magnesium hydroxide Magnesium hydroxide 120 120 120 120 (MAGNIFINA Grades (MAGNIFINA Grades H10A) except in the case of CM-95. H10A) It is considered that the size of diameter and the length of tube Carbon nano tube O 2 4 6 influence mechanical properties and flame retardancy. (CNT75) Namely, CM-95 has too small diameter with too long length (Outer D. = 60-80 nm) Pentaerythritol 1 1 1 1 which leads to poor compatibility with the other components, tetrakis(3(3,5-di tert-buty consequently CM-95 formulations show poor results of 4-hydroxyphenyl)propionate mechanical properties and flame retardancy. (Irganox1010) 0072 From the results of mechanical properties and flame Tensile strength (MPa) 10.3 10.7 10.3 11.8 Elongation at break(%) 2OO 190 16S 190 retardancy, CNT50 contained formulations show the best LOI (%) 33 35.5 36.5 40 results in both properties. When only CNT50 formulations and carbon black formulations are compared in terms of mechanical properties (i.e. elongation at break and tensile 0070 Elongation at break and tensile strength of EVA/120 strength), it is apparent that CNT50 contained formulations phr H10A formulations as a function of CNT or carbon black show much higher properties than carbon black formulations. content are shown in FIGS. 2 and 3. Surprisingly, different Accordingly, it is considered that CNT50 has proper size and trends are demonstrated by different CNTs even though the length for use in clean flame retardant compositions. Namely, content is the same and is quite Small. At the range of up to 4 CNT of outer diameter of 40-60 nm and length distribution of phr content, elongationatbreak decreases and tensile strength under 20 um can be used in thermoplastic clean flame retar increases with increase of CNT content. It is interesting to dant compositions instead of carbon black to increase notice that CM-95 contained formulations show the lowest mechanical properties and flame retardancy. Therefore, CNT elongation at break and the highest tensile strength among all 50 is selected for detailed comparative investigation with investigated formulations including carbon black contained carbon black. formulations. It is observed that smaller particle size shows 0073. The following non-limiting examples illustrate for higher tensile strength, therefore, CM-95 shows the highest mulations of the invented compositions. tensile strength and carbon black shows the lowest tensile strength. It is considered that mechanical properties depend EXAMPLE 1. mainly upon the size of particles. 0.074

Content Property 1 2 3 4 Ethylene vinyl acetate 8O 8O 8O 8O (Evaflex 360) Linear low density 2O 2O 2O 2O polyethylene (LLDPE 118W) Magnesium hydroxide 120 120 120 120 (MAGNIFINA Grades H10A) Carbon black (Corax N550) Carbon nano tube (CNT50) O 2 4 6 (Outer D = 40-60 nm) Pentaerythritol 1 1 1 1 etrakis(3(3,5-di tert-buty 4-hydroxyphenyl)propionate (Irganox1010) Tensile strength (MPa) 12 13 14 14 Elongation at break(%) 18O 175 170 170 Thermal Retention of Over 80% aging at tensile OOC strength (%) or 168 Retention of Over 80% S elongation at break (%) LOI (%) 34 38 39 39 UL 94 test H-B H-B H-B V-2 Volume resistivity(S2cm) 4 x 10 2 x 10 2 x 10 1 x 10 US 2011/O168425 A1 Jul. 14, 2011

0075 Volume resistivity is measured at room temperature Then, rest of additives and flame retardants are mixed with (25°C.) in accordance with ASTM D257 using high resis already melted polymers for 10 minutes at 150° C. The pre tance meter of Model HP4339B, HP, USA. From the results, mixed compounds are moved to two roll mill/guider cutter/ it is observed that even the highest CNT50 content (6 phr (per pelletizing extruder and then pelletized. At this step, tempera hundred resin)) by weightformulation (run No. 4) shows very ture of two roll mixer is kept around 150° C. and mixture is high volume resistivity (S.2cm). Therefore, it is apparent that processed for 5-10 minutes. CNT50 contained formulations that are suitable to be used in cable insulation materials. I0083. Another important processing parameter for clean 0076. As shown in FIGS. 5 and 6, it is observed that flame retardant materials compared to routine thermoplastics CNT50 formulations show higher mechanical properties is that the extruding temperature of clean flame retardant compared to carbon black formulations. Elongation at break materials is 160°C-200°C. while that of routine thermoplas slightly increases with increase of CNT50 content while elon tics is 200-250° C. The extruding temperature of clean flame gation at break slightly decreases with increase of carbon retardant materials is lower than routine thermoplastics Such black content. In addition, tensile strength increases with as polyethylene because clean flame retardant materials are increase of CNT50 or carbon black, however the rate of mainly consisted of low softening temperature grade poly increase for CNT50 content is higher than that of carbon mers such as EVA (Ethylene VinylAcetate), Ethylene Alpha black content. Namely, higher values are obtained by CNT50 Olefin or Ethylene Ethyl Acrylate. compared to carbon black for both mechanical properties. I0084. Sheets of test specimen for mechanical properties These results show that CNT50 may be very suitable flame and flame retardancy are prepared by hot press and com retardant in thermoplastic clean flame retardant compositions pressed at 180° C. for 10 minutes with thickness of 2 mm. if the same or higher flame retardancy is achieved with CNTSO. Likewise, the above materials are preferably extruded attem 0077. As shown in FIG. 7, surprisingly, higher flame retar perature 160°C-200°C. onto conductors to prepare the insu dancy is observed by CNT50 formulations compared to car lated cable and check process ability. This extruding process bon black formulations. Flame retardancy increases with is exactly the same as routine thermoplastic method. During increase of CNT50 or carbon black content. However, the rate cable extrusion of above compositions, non CNT 50 content of increase for composition (run number 1) and 2-4 parts CNT 50 per hun 0078 CNT50 formulations is higher than that of carbon dred resin by weight (run numbers 2 and 3) show the best black formulations. process ability and excellent Surface Smoothness of finished 0079. In addition, volume resistivity (S.2cm) of CNT 50 cables. and carbon black formulations is over 1x10'S 2cm which is Sufficient for use in wire and cable insulation and jacket I0085 Similar to Example 1, ethylene vinyl acetate materials. (Evaflex 360)/magnesium hydroxide (KISUMA 5B) (120 0080 From the overall results of mechanical properties, phr)/CNT 50 formulations are conducted. The detailed flame retardancy and electrical properties for CNT 50/carbon examples of formulations are shown in EXAMPLE 2. As black formulations, CNT50 is really a suitable material which shown in results for ethylene vinyl acetate (Evaflex 360)/ can be used instead of carbon black in thermoplastic clean magnesium hydroxide (MAGNIFINA Grades H10A) (120 flame retardant compositions. phr) formulations, 2-4 parts CNT 50 per hundred resin by 0081. The main key points of this invention are re-con weight show the best performance. Non CNT 50 content firmed from above experimental. Namely, CNT of outer composition (run number 5) and 2-4 parts CNT 50 per hun diameter of 40-60 nm and length distribution of under 20 um dred resin by weight (run numbers 6 and 7) show the best can be used in thermoplastic clean flame retardant composi process ability and excellent Surface Smoothness of finished tions instead of carbon black to improve mechanical proper cables. ties and flame retardancy. 0082. The compounding of above compositions is prefer EXAMPLE 2 ably conducted as follows, namely, EVA and LDPE are melted and mixed in internal mixerfor four minutes at 150° C. 0086

Content Property 5 6 7 8 Ethylene vinyl acetate (Evaflex 8O 8O 8O 8O 360) Linear low density polyethylene 2O 2O 2O 2O (LLDPE 118W) Magnesium hydroxide (KISUMA 120 120 120 120 5B) Carbon nano tube (CNT50) O 2 4 6 (Outer D = 40-60 nm) Pentaerythritol tetrakis(3(3,5-di tert-buty 4-hydroxyphenyl)propionate (Irganox1010) Room Tensile 10 10 10 10 temperature strength (MPa) Elongation at 550 500 450 440 break (%) US 2011/O168425 A1 Jul. 14, 2011 10

-continued

Content Property 5 6 7 8 Thermal Retention of Over 80% aging at tensile 100° C. strength (%) for 168 Retention of Over 80% hrs elongation at break (%) LOI (%) 27 30 33 35 UL 94 test H-B H-B H-B V-2 Volume resistivity(S2cm) 3 x 101 3 x 101 1 x 101 1 x 101

0087 To increase flame retardancy and achieve V-0 of is greatly decreased as shown in Conventional EXAMPLE 3. UL94 test, intumescent flame retardants such as Exolit RP In addition, all compositions show excellent thermal proper 692 (red phosphorus masterbatch, producer: Clariant/France, ties by passing thermal aging test (100° C.x136 hrs). phosphorus content: approx. 50% (w/w)), Firebrake ZB (Zinc I0089. Non CNT 50 content composition (run number 9) borate, producer: Borax/USA) and Boric Acid (Producer: Rose Mill Chemicals & Lubricant/USA) are used in ethylene and 2-4 parts CNT 50 per hundred resin by weight (run vinyl acetate (Evaflex 360)/magnesium hydroxide (MAGNI numbers 10 and 11) compositions show the best process FINA Grades H10A) (120 phr) formulations as shown in ability and excellent surface smoothness for finished cables. EXAMPLE 3. Processing of test specimen and cable extru sion is the same as previous methods. EXAMPLE 3 I0088. From the results, it is found that 2-4 parts CNT 50 per hundred resin by weight (run numbers 10 and 11) com- 0090

Content Property 9 10 11 12 Ethylene vinyl acetate 8O 8O 8O 8O (Evaflex 360) Linear low density poly- 2O 2O 2O 2O ethylene (LLDPE 118W) Magnesium hydroxide 130 130 130 130 (MAGNIFINA Grades H10A) Red phosphorus 5 5 5 5 (RP-692) Zinc borate 5 5 5 5 (Firebrake ZB) Boric acid 2 2 2 2 Carbon nano tube (CNT50) O 2 4 6 (Outer D = 40-60 nm) Pentaerythritol 1 1 1 1 etrakis(3(3,5-di tert-buty 4-hydroxyphenyl)propionate (Irganox 1010) Room Tensile 10 11 11 11.5 emperature strength (MPa) Elongation at 150 145 145 140 break (%) Thermal Retention of Over 80% aging at tensile 100° C. strength (%) for 168 Retention of Over 80% hrs elongation at break (%) LOI (%) 34 36 38 39 UL 94 test W-O W-O W-O W-O Volume resistivity(S2cm) 2 x 101 1 x 101 2 x 101 9 x 104 positions show excellent mechanical properties and flame 0091 Although the present embodiments have been retardancy. Specially, all compositions meet V-0 of UL94 test described with reference to specific example embodiments, it and volume resistivity (G2cm) is sufficient for use in wire and will be evident that various modifications and changes may be cable insulation materials. Elongation at break of run num made to these embodiments without departing from the bers 10 and 11 decreases slightly at CNT 50 content of 2-4 broader spirit and scope of the various embodiments. Accord parts per hundred resin by weight. If carbon black is used in ingly, the specification and examples are to be regarded in an run numbers 10 and 11 instead of CNT 50, elongation at break descriptive rather than a restrictive sense. US 2011/O168425 A1 Jul. 14, 2011 11

What is claimed is: 12. A method according to claim 11 further comprising 1. A thermoplastic extrudable composition comprising: adding 2-6 parts by weight of the carbon nano tube. a polymer 100 parts by weight; 13. A method of claim 11 further comprising: an inorganic flame retardant 50-250 parts by weight; extruding the thermoplastic extrudable composition with an secondary flame retardant 0-100 parts by weight; outpost curing. an antioxidant 0.1-1.5 parts by weight; 14. A method of claim 13 further comprising: a processing aid 1-10 parts; and maintaining an extruding temperature between 160-200 a carbon nano tube 1-6 parts by weight. 2. A composition according to claim 1, wherein the poly C. mer is 50% below the total weight of the thermoplastic 15. A cable comprising: extrudable composition and the inorganic flame retardant and a wire; the intumescent flame retardant have a particle size that is an insulation sheath encompassing the wire, wherein the under 50 um. insulation sheath is blended from a thermoplastic 3. A composition according to claim 1, wherein the base extrudable composition comprising the following com polymer is at least one of ethylene vinyl acetate (EVA), EVA ponents: polyethylene, ethylene alpha olefin, ethylene alpha olefin a polymer 100 parts by weight; polyethylene, ethylene ethyl acrylate, ethylene ethyl acrylate a polyethylene polymer 20 parts by weight; polyethylene, EVA-polyethylene-ethylene propylene diene an inorganic flame retardant 50-250 parts by weight; monomer (EPDM), ethylene alpha olefin-polyethylene an secondary flame retardant 0-100 parts by weight; EPDM and ethylene ethyl acrylate-polyethylene-EPDM. an antioxidant 0.1-1.5 parts by weight; 4. A composition according to claim 3, wherein the base a processing aid 1-10 parts; and polymer is ethylene vinyl acetate (EVA). a carbon nano tube 1-6 parts by weight. 5. A composition according to claim 1, wherein the carbon 16. A cable according to claim 15, wherein the insulation is nano tube is a multi-walled nano tube. a thermoplastic extrudable composition without post curing, 6. A composition according to claim 5, wherein the outer and wherein the extruding temperature is maintained between diameter of the carbon nano tube is 40-60 nm and the length 1609 -200° C. is less than 20 um. 7. A composition according to claim 1, wherein the inor 17. A cable according to claim 15, wherein the base poly ganic flame retardant is at least one of aluminum trihydroix mer is less than 50% parts by weight, thermoplastic extrud ide (ATH), magnesium hydroxide (MH) and huntite hydro able composition is extruded without post curing and the magnesite (HH). inorganic flame retardant and the secondary flame retardant 8. A composition according to claim 1, wherein the sec have a particle size that is under 50 um. ondary flame retardant is at least one of red phosphorus, Zinc 18. A cable according to claim 15, wherein the outer diam borate, Zinc acid and ammonium octamolybdate (AOM). eter of the carbon nano tube is 40-60 nm and the length is less 9. A composition of claim 1, wherein the inorganic flame than 20 um. retardant is a non halogen flame retardant. 19. A cable, comprising: 10. A method of mixing athermoplastic composition, com a wire; prising: a coating on the wire comprising: melting a composition for 10 minutes at 150° C. compris a polymer 100 parts by weight; 1ng: a polyethylene polymer 20 parts by weight; a polymer 100 parts by weight; and an inorganic flame retardant 50-250 parts by weight; a polyethylene polymer 20 parts by weight. an secondary flame retardant 0-100 parts by weight; 11. A method according to claim 10, further comprising: an antioxidant 0.1-1.5 parts by weight; adding the following to the composition as a mixture, a processing aid 1-10 parts; and an inorganic flame retardant 50-250 parts by weight; a carbon nano tube 1-6 parts by weight. an intumescent flame retardant 0-100 parts by weight; 20. A cable of claim 19, wherein the carbon nano tube is an antioxidant 0.1-1.5 parts by weight; CNT50, wherein 2-4 parts by weight of CNT 50 is used, a processing aid 1-10 parts; and wherein the UL 94 test result is VO. a carbon nano tube 1-6 parts by weight. mixing for 10 minutes at 150° C. c c c c c