Decabromodiphenylethane-free flame-retardant thermoplastic composition

Abstract

1. A method of replacing decabromodiphenylethane in a flame-retardant thermoplastic composition with a combination of (a) a thermoplastic polymer; (b) an aromatic brominated flame retardant that is not decabromodiphenylethane; and (c) a synergist for said aromatic brominated flame retardant. 2. A flame-retardant thermoplastic composition comprising: (a) a thermoplastic polymer; (b) an aromatic brominated flame retardant that is not decabromodiphenylethane; and (c) a synergist for said aromatic brominated flame retardant, the composition being free of decabromodiphenylethane.

Description

[Technical Field]

[0001] The present invention relates to a method for replacing decabromodiphenylethane brominated flame retardants in thermoplastic polymer compositions with decabromodiphenylethane-free flame retardant thermoplastic compositions. [Background technology]

[0002] Halogenated flame retardants are well known and widely available. These products are used in a variety of polymer compositions to provide various levels of flame retardancy for a variety of applications, such as wire and cable. When formulated at high concentrations, these products can provide excellent flame retardancy, but their high formulation levels make it difficult to achieve a balance of desired properties, such as mechanical properties (such as compressive strength), electrical properties (such as wet insulation resistance), and extrusion properties (such as observed die pressure).

[0003] Decabromodiphenylethane (DBDPE) is a general-purpose, brominated, high-purity, non-DPO (diphenyl oxide)-based flame retardant for a variety of polymers, including styrenics, engineering polymers, polyolefins, and elastomers, commercially available from LANXESS under the trade name Firemaster® 2100R. DBDPE is one of the few "universally" applicable flame retardants in use today. However, DBDPE has come under some increased regulatory scrutiny. Therefore, there is a need for DBDPE-free flame-retardant compositions that are compatible with a variety of polymers, especially polyolefins used in wire and cable applications.

[0004] A variety of brominated replacements for DBDPE are available on the market and have been proposed for a variety of polymer applications.

[0005] For example, US 2020 / 0216650A1 discloses a silane-functionalized composition for wire and cable applications, comprising 16 to 70 wt. % of a polymeric brominated flame retardant having a weight-average molecular weight (Mw) of 1,000 g / mol or greater (≥ 1,000 g / mol). Exemplary brominated flame retardants are brominated polyphenyl ether (Emerald Innovation™ 1000) and brominated styrene / butadiene block copolymer (Emerald Innovation™ 3000). The composition further contains 0.3 to 5 wt. % or 10 to 79 wt. % of an alkoxysilane.

[0006] No. 8,420,876 discloses the preparation of oligomeric or polymeric mixtures comprising 1,3-diphenylpropane, 1,3,5-triphenylpentane, 1,3,5,7-tetraphenylheptane, and 1,3,5,7,9-pentaphenylnonane, having a polydispersity greater than 1.25 and suitable for bromination as flame retardants for polyurethane foam applications.

[0007] US 8,642,821 discloses a method for producing a brominated flame retardant composition, which involves brominating a feedstock containing anionic, chain transfer-derived toluene and styrene telomer distributions in the presence of a catalytic amount of AlBr3 and a solvent. Although no formulated examples are provided, the resulting flame retardant may be suitable for a variety of thermoplastic resins.

[0008] One drawback of these disclosures is that they either do not provide burn results or only provide horizontal burn results. The horizontal burn test is a significantly less demanding test than the UL-94 vertical burn test. There is a need for a vertical burn test-effective alternative to existing DBDPE-free flame retardant compositions. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] US 2020 / 0216650A1 [Patent Document 2] US 8,420,876 [Patent Document 3] US 8,642,821 Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present disclosure is to provide a DBDPE-free flame retardant composition that demonstrates effectiveness in a vertical burn test. These compositions are desirable for use in thermoplastic polyolefin compositions. Accordingly, another object is to provide a thermoplastic polyolefin composition, such as a polyolefin used in wire and cable, that includes a DBDPE-free flame retardant. [Means for solving the problem]

[0011] The present disclosure provides a method for replacing decabromodiphenylethane in flame retardant thermoplastic compositions, particularly those containing polyolefins such as polypropylene or polyethylene. (a) at least one thermoplastic polyolefin; (b) at least one aromatic brominated flame retardant that is not decabromodiphenylethane; and (c) at least one synergist A DBDPE-free thermoplastic polyolefin composition is prepared from the combination of

[0012] The method can also include forming the flame retardant thermoplastic composition into an article. In certain embodiments, the flame retardant thermoplastic composition does not include an alkoxysilane, an alkoxysilane-functionalized polymer, and / or a silanol condensation catalyst.

[0013] (a) at least one thermoplastic polyolefin; (b) at least one aromatic brominated flame retardant that is not decabromodiphenylethane; and (c) at least one synergist Also described herein are flame retardant thermoplastic compositions comprising:

[0014] In some embodiments, the flame retardant thermoplastic composition does not include an alkoxysilane, an alkoxysilane-functionalized polymer, and / or a silanol condensation catalyst.

[0015] Advantageously, the methods and compositions described herein do not require the use of alkoxysilanes, alkoxysilane-functionalized polymers, and / or silanol condensation catalysts similar to those described in US 2020 / 0216650A1. Additionally, the methods and compositions provide thermoplastic articles that meet the requirements of UL 94 testing for flammability of plastic materials for devices and consumer electronics components as of December 1, 2021. Preferably, molded articles of the compositions have a UL 94 V0 rating at thicknesses of 0.2 mm to 3.2 mm, such as about 0.2 mm, about 0.4 mm, about 0.8 mm, about 1.6 mm, and about 3.2 mm.

[0016] (d) at least one auxiliary processing aid, such as at least one antioxidant and / or at least one heat stabilizer; and (e) at least one inorganic filler, including but not limited to talc The method and flame retardant thermoplastic composition may further comprise one or more of:

[0017] Each based on the total weight of the composition (b) an aromatic brominated flame retardant in an amount of about 5% to about 40% by weight, and (c) at least one synergist in an amount of about 1% to about 20% by weight, the flame retardant thermoplastic composition generally tolerates.

[0018] The thermoplastic polyolefin may be filled or unfilled. In some embodiments, the (a) at least one thermoplastic polyolefin comprises or is polypropylene. In other embodiments, the (a) polyolefin comprises or is polyethylene.

[0019] In certain preferred embodiments, (b) the at least one aromatic brominated flame retardant is selected from a phenoxy-terminated carbonate oligomer of tetrabromobisphenol A, a homopolymer of dibromostyrene, or poly(2,6-dibromophenol oxide). In some of these embodiments, (b) the aromatic brominated flame retardant is a phenoxy-terminated carbonate oligomer of tetrabromobisphenol A.

[0020] In some embodiments, the ratio of (b) the at least one aromatic brominated flame retardant to (c) the at least one synergist is from about 1:10 to about 10:1, preferably from about 1:1 to about 5:1, and more preferably from about 1:1 to about 3:1. In preferred embodiments, the (c) at least one synergist comprises antimony and / or melamine polyphosphate.

[0021] In certain embodiments, (c) the at least one synergist comprises an aliphatic brominated flame retardant. In some of these embodiments, the ratio of aromatic brominated flame retardant to aliphatic brominated flame retardant is from about 1:1 to about 2:1. In some embodiments, the aromatic brominated flame retardant is a phenoxy-terminated carbonate oligomer of tetrabromobisphenol A and the aliphatic brominated flame retardant is a brominated styrene / butadiene block copolymer.

[0022] In some embodiments, (a) the thermoplastic polymer is unfilled, (c) the synergist comprises an aliphatic brominated flame retardant, and (b) the ratio of aromatic brominated flame retardant to aliphatic brominated flame retardant is from about 1:1 to about 2:1. In some of these embodiments, the aromatic brominated flame retardant is a phenoxy-terminated carbonate oligomer of tetrabromobisphenol A and the aliphatic brominated flame retardant is a brominated styrene / butadiene block copolymer.

[0023] Also described are methods for making the flame retardant thermoplastic compositions; and articles containing the thermoplastic polymer compositions.

[0024] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. DETAILED DESCRIPTION OF THE INVENTION

[0025] The present disclosure relates to a method for replacing decabromodiphenylethane in flame-retardant thermoplastic compositions. The thermoplastic polymer may be polyester, polyamide, polystyrene, including high-impact polystyrene (HIPS), polyolefin, polycarbonate, polyurethane, polyphenylene ether, or other thermoplastic polymer. More than one thermoplastic polymer (thermoplastic polymer blend) can be used, such as polyphenylene ether / styrene blends, polyvinyl chloride / acrylonitrile butadiene styrene (ABS), or methacrylonitrile and α-methylstyrene containing ABS, and other impact-modified polymers such as polyester / ABS or polycarbonate / ABS. The thermoplastic polymer may be unreinforced or reinforced, for example, glass-filled polyester (e.g., glass-filled polyalkylene terephthalate) or glass-filled polyamide.

[0026] Exemplary polymers include crosslinked and uncrosslinked olefin polymers, such as ethylene homopolymers, propylene homopolymers, and butylene homopolymers, copolymers of two or more of these alkene monomers, and copolymers of one or more of these alkene monomers and other copolymerizable monomers, such as ethylene / propylene copolymers, ethylene / ethyl acrylate copolymers, and ethylene / propylene copolymers, ethylene / acrylate copolymers, and ethylene / vinyl acetate copolymers, polymers of olefinically unsaturated monomers, such as polystyrene, for example, high-impact polystyrene, and styrene copolymers, and polyurethanes. Preferably, the polyolefin is polypropylene and / or polyethylene.

[0027] The at least one thermoplastic polymer (a) is typically present in the flame retardant thermoplastic composition in an amount ranging from about 30 to about 95 wt. %, for example, from about 40 to about 90 wt. %, or from about 50 to about 90 wt. %, based on the total weight of the flame retardant thermoplastic composition.

[0028] Aromatic brominated flame retardants are not DBDPE, but are typically brominated aromatic polymers or oligomers.

[0029] Exemplary brominated flame retardants that can be used in the compositions herein include brominated styrene / butadiene block copolymers (e.g., Emerald Innovation™ 3000), phenoxy-terminated carbonate oligomers of tetrabromobisphenol A (e.g., BC-58™), homopolymers of dibromostyrene (e.g., Firemaster® PBS-64 HW), 1,1′-(isopropylene)bis[3,5-dibromo-4-(2,3-dibromo-2-methoxypropoxy)benzene] (SR-130), ethylene bistetrabromophthalimide (SAYTEX® BT-93), brominated triazines such as tris(tribromophenoxy)triazine (e.g., FR-245), poly(2,6-dibromophenoloxide) (UNIPLEX FRP 64), polybromostyrene copolymerized with another monomer (e.g., Firemaster® CP-44HF), and combinations thereof.

[0030] In certain preferred embodiments, the aromatic brominated flame retardant is selected from phenoxy-terminated carbonate oligomers of tetrabromobisphenol A, homopolymers of dibromostyrene, or poly(2,6-dibromophenoloxide).

[0031] The amount of aromatic brominated flame retardant (b) used in the flame-retardant thermoplastic composition will be that amount necessary to obtain the desired flame retardancy. Generally, the composition and final product may contain about 1 to about 40 wt. %, preferably about 5 to about 40 wt. %, for example, about 15 to about 30 wt. %, or about 5 to about 25 wt. % of the brominated flame retardant. Masterbatches of polymers containing the aromatic brominated flame retardant blended with additional amounts of base polymer or binder typically contain higher concentrations of the flame retardant, for example, up to 95 wt. % or more.

[0032] In certain instances, combinations of brominated flame retardants may be used in thermoplastic formulations. The combinations used may depend on the thermoplastic material. For example, it has been surprisingly determined that combinations of aromatic brominated flame retardants, such as phenoxy-terminated carbonate oligomers of tetrabromobisphenol A, can exhibit synergistic effects when combined with aliphatic brominated flame retardants, such as brominated styrene / butadiene block copolymers, in polypropylene and polyethylene. In this case, the aliphatic flame retardant acts as a synergist (component c) for the aromatic brominated flame retardant (component b).

[0033] Examples of additional flame retardant synergists (c) include antimony, condensation products of melamine (e.g., melam, melem, melon), melamine cyanurate, reaction products of melamine and polyphosphoric acid (e.g., dimelamine pyrophosphate, melamine polyphosphate), reaction products of condensation products of melamine and polyphosphoric acid (e.g., melem polyphosphate, melam polyphosphate, melon polyphosphate), melamine-poly(metal phosphates) (e.g., melamine-polyzinc phosphate), reaction products of trichlorotriazine, piperazine, and morpholine, e.g., triazine-based compounds such as poly-[2,4-(piperazin-1,4-yl)-6-(morpholin-4-yl)-1,3,5-triazine]piperazine (e.g., MCA® PPM Triazine HF), aluminum dialkyl phosphinates, organic phosphinates such as aluminum diethyl phosphinate (Exolit® OP), and aluminum hydrogen phosphite (Al2(HPO3)3).

[0034] In certain embodiments, the synergist is a nitrogen-containing synergist. Suitable nitrogen-containing synergists may be selected from, for example, melamine derivatives such as melamine and melamine condensation products (melam, melem, melon, or similar compounds with higher condensation degrees), melamine cyanurate, and phosphorus / nitrogen compounds such as dimelamine phosphate, dimelamine pyrophosphate, melamine phosphate, melamine pyrophosphate, melamine polyphosphate, melam polyphosphate, melon polyphosphate, and melem polyphosphate, and mixed polysalts thereof.

[0035] Examples of additional flame retardants suitable as synergists include halogenated flame retardants, alkyl or aryl phosphine oxide flame retardants, alkyl or aryl phosphate flame retardants, alkyl or aryl phosphonates, alkyl or aryl phosphinates, and salts of alkyl or aryl phosphinic acids. Typically, the additional flame retardant is an alkyl or aryl phosphate (e.g., triphenyl phosphate, bisphenol A bis(diphenyl phosphate), resorcinol bis(diphenyl phosphate), or resorcinol bis(dixylenyl phosphate)).

[0036] In some embodiments, the synergist is a phosphorus-based flame retardant. For example, aromatic brominated flame retardants such as phenoxy-terminated carbonate oligomers of tetrabromobisphenol A have been shown to exhibit synergistic effects with melamine polyphosphate when used with unfilled polyethylene. Alternative phosphorus-based flame retardants are expected to exhibit similar effects.

[0037] In other embodiments, when mineral-filled polyethylene is used, an aliphatic brominated flame retardant, such as a homopolymer of dibromostyrene, is used as a synergist.

[0038] In a preferred embodiment, it is advantageous to use an antimony-based synergist, such as Sb2O3, in combination with the brominated flame retardants disclosed herein. Generally, the flame retardant products of the present invention are used with the antimony-based synergist in a weight ratio ranging from about 1:1 to 7:1, preferably from about 1:1 to about 3:1.

[0039] As demonstrated herein, when using the combination of aromatic bromine-containing flame retardants and synergists described in this disclosure, the use of a nitrogen-containing synergist or nitrogen-containing flame retardant is not required to obtain excellent flame retardant performance and processing stability in thermoplastic polymer applications. Thus, in some embodiments, the thermoplastic flame retardant compositions of this disclosure do not include a nitrogen-containing synergist or nitrogen-containing flame retardant.

[0040] The amount of synergist typically ranges from about 1 to about 20 weight percent, such as from about 10 to about 15 weight percent, of the thermoplastic composition.

[0041] The thermoplastic composition may consist essentially of, or consist of, components (a), (b), and (c), and optionally any one or combination of components (d) and (e).

[0042] Auxiliary processing aids (d) and fillers (e) are typically used in amounts less than 10% by weight of the flame retardant thermoplastic composition, e.g., less than 5% by weight, e.g., 3% by weight or less. Non-limiting examples of auxiliary processing aids (d) include antioxidants, UV stabilizers, lubricants, impact modifiers, plasticizers, acid scavengers (e.g., carbodiimides or epoxides), phosphide inhibitors, pigments, dyes, optical brighteners, antistatic agents, anti-drip agents such as PTFE, and other additives used to improve the properties of the resin.

[0043] The thermoplastic composition may include one or more heat stabilizers. Examples of suitable heat stabilizers include metal hydroxides, oxides, oxide hydrates, borates, molybdates, carbonates, sulfates, phosphates, silicates, siloxanes, stannates, mixed oxide-hydroxides, oxide-hydroxide-carbonates, hydroxide-silicates, hydroxide-borates, preferably wherein the metal is zinc, magnesium, calcium, or manganese, typically zinc. For example, the one or more heat stabilizers may be selected from zinc borate, zinc stannate, zinc molybdate complexes (e.g., Kemgard® 911B), zinc molybdate / magnesium hydroxide complexes (e.g., Kemgard® MZM), zinc molybdate / magnesium silicate complexes (e.g., Kemgard® 911C), calcium / zinc molybdate complexes (e.g., Kemgard® 911A), and zinc phosphate complexes (e.g., Kemgard® 981), montmorillonite, kaolinite, halloysite, and hydrotalcite. When present, the amount of the at least one heat stabilizer is typically 0.1 to 5% by weight, based on the total weight of the flame-retardant thermoplastic composition.

[0044] At least one inorganic filler may be present in the flame-retardant thermoplastic composition. As known in the art, inorganic fillers can reduce the mold shrinkage and linear expansion coefficient of the final molded product and improve high- and low-temperature impact properties. Various fillers, either fibrous or non-fibrous (e.g., powder or plate-like) in shape, may be used depending on the desired product. Some examples of fibrous fillers, which are a type of inorganic filler, include glass fiber, glass fiber with a noncircular cross section such as flat fiber, carbon fiber, silica fiber, silica-alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, and even metal fiber materials such as stainless steel, aluminum, titanium, copper, and brass. Common fibrous fillers are glass fiber or carbon fiber. Alternatively, the inorganic filler may be a powder filler such as carbon black, graphite, silica, quartz powder, glass beads, glass powder, silicates such as calcium silicate, kaolin, talc, clay, diatomaceous earth, and wollastonite; metal oxides such as iron oxide, titanium oxide, zinc oxide, and alumina; metal hydroxides; metal carbonates such as calcium carbonate and magnesium carbonate; metal sulfates such as calcium sulfate and barium sulfate; silicon carbide, silicon nitride, boron nitride, and various metal powders. Other examples of inorganic fillers include plate-like fillers such as mica, glass flakes, and various metal foils. These inorganic fillers can be used alone or in combination. Before use, the inorganic filler is preferably treated with a size or surface treatment agent, if necessary.

[0045] When present, the amount of the at least one inorganic filler (e) in the flame retardant thermoplastic composition is typically from 1 to 50% by weight, e.g., from 5 to 50% by weight, from 10 to 40% by weight, or from 15 to 30% by weight, based on the total weight of the flame retardant thermoplastic composition.

[0046] Thermoplastic articles formed from formulations containing the thermoplastic polymers and brominated flame retardant compositions described herein can be produced by conventional methods, such as, for example, injection molding, extrusion, compression molding, etc. In certain cases, blow molding may also be appropriate.

[0047] In one embodiment, the desired product is a molded article of the composition meeting a UL94 V0 rating at a thickness of 0.4 mm, 0.8 mm, 1.6 mm, or between 0.2 and about 3.2 mm.

[0048] To achieve good flame performance (UL94 V0) for thin wall articles (e.g., 0.8 mm and thinner), a short flameout time is required while preventing flaming drips during UL94 testing. The addition of anti-drip agents can prevent flaming drips, while a short flameout time is usually achieved by using flame retardants. [Example]

[0049] The following examples are illustrative of the flame retardant thermoplastic formulations of the present disclosure.

[0050] The formulations shown in Table 1 were compounded using a twin-screw extruder at a barrel temperature of 200 to 220°C. To evaluate their suitability as DBDPE replacements in exemplary polyolefins used in wire and cable products, the amount of brominated flame retardant was 30% by weight. Samples of various thicknesses were prepared using an injection molding machine at 200 to 220°C, with molding temperatures of 50 to 60°C. The formulations were evaluated for flame retardant activity in the UL94 vertical flame test and processing stability. "V-0" indicates the highest rating, and "V-2" indicates the lowest rating before failure.

[0051] [Table 1]

[0052] As shown in Table 1, the inclusion of antimony trioxide and 30 wt% of various aromatic brominated flame retardants (BrFRs) in inorganic-filled polypropylene achieved UL-94 V-0 at a thickness of 1.6 mm, while the same result was not observed with 15 wt% aromatic BrFRs. The addition of an aliphatic flame retardant to the aromatic flame retardant did not result in suitable flame retardancy.

[0053] [Table 2]

[0054] In contrast to the talc-filled polypropylene of Example 1, unfilled polypropylene did not benefit from the inclusion of antimony trioxide and 30 wt.% aromatic brominated flame retardant. However, when the aliphatic brominated flame retardant was fed to the aromatic flame retardant such that the ratio of aromatic brominated flame retardant to aliphatic brominated flame retardant was 1:1 or greater, the aromatic brominated flame retardant with antimony synergist achieved UL-94 V-0 at a thickness of 1.6 mm.

[0055] [Table 3]

[0056] In contrast to the unfilled polypropylene of Example 2, the unfilled polyethylene achieved UL-94 V-0 at a thickness of 1.6 mm not only when the ratio of aromatic brominated flame retardant to aliphatic brominated flame retardant was 1:1, but also when it contained antimony cinerator and 30% aromatic brominated flame retardant.

[0057] It was concluded that DBDPE, when used alone or with other synergists, can successfully replace other aromatic and aliphatic brominated flame retardants in polyolefin formulations. Polyolefins were used in this example. However, it is expected that the flame retardant compositions of the present disclosure may be suitable for other polymers, such as HIPS (high impact polystyrene) and ABS (acrylonitrile butadiene styrene). In those cases, adjustments to the amount of aliphatic and aromatic flame retardants and / or the amount of synergist used to replace DBDPE may be necessary.

[0058] The present invention may comprise, consist of, or consist essentially of the materials and / or steps described herein. In particular, the following embodiments are within the scope of the present disclosure:

[0059] 1.(a) Thermoplastic polyolefin polymers; (b) an aromatic brominated flame retardant that is not decabromodiphenylethane; and (c) Aromatic brominated flame retardant synergists and is free of decabromodiphenylethane.

[0060] 2. The flame-retardant thermoplastic composition of embodiment 1, wherein a molded article of the composition is 0.2 mm to 3.2 mm thick and has a UL 94 V0 rating.

[0061] 3. The flame retardant thermoplastic composition of embodiment 1 or 2, wherein the aromatic brominated flame retardant is a phenoxy-terminated carbonate oligomer of tetrabromobisphenol A, a homopolymer of dibromostyrene, or poly(2,6-dibromophenoloxide).

[0062] 4. The flame retardant thermoplastic composition of any one of embodiments 1 to 3, wherein the synergist comprises antimony and / or melamine polyphosphate.

[0063] 5. The flame retardant thermoplastic composition of any one of embodiments 1 to 5, wherein the ratio of aromatic brominated flame retardant to synergist is from about 1:10 to 10:1.

[0064] 6. The flame retardant thermoplastic composition of any one of embodiments 1 to 5, wherein the aromatic brominated flame retardant is about 5 to 40% by weight of the composition.

[0065] 7. The flame retardant thermoplastic composition of any one of embodiments 1 to 6, wherein the synergist is from about 1% to about 20% by weight of the composition.

[0066] 8. The flame retardant thermoplastic composition of any one of the preceding embodiments, further comprising at least one auxiliary process-aid, such as an antioxidant or a heat stabilizer.

[0067] 9. The flame retardant thermoplastic composition of any one of embodiments 1 to 8, further comprising an inorganic filler.

[0068] 10. The flame retardant thermoplastic composition of any one of embodiments 1 to 8, wherein the synergist comprises an aliphatic brominated flame retardant.

[0069] 11. The flame retardant thermoplastic composition of embodiment 10, wherein the ratio of aromatic brominated flame retardant to aliphatic brominated flame retardant is from about 1:1 to about 2:1.

[0070] 12. The flame retardant thermoplastic composition of embodiment 11, wherein the thermoplastic polymer is unfilled.

[0071] 13. The flame retardant thermoplastic composition of any one of embodiments 10 to 12, wherein the aromatic brominated flame retardant is a phenoxy-terminated carbonate oligomer of tetrabromobisphenol A and the aliphatic brominated flame retardant is a brominated styrene / butadiene block copolymer.

[0072] 14. The flame retardant thermoplastic composition of any one of embodiments 1 to 5, wherein the composition is filled with a thermoplastic polymer.

[0073] 15.(a) Thermoplastic polyolefin polymers; (b) an aromatic brominated flame retardant that is not decabromodiphenylethane; and (c) Synergists of aromatic brominated flame retardants and a method for preparing a flame retardant thermoplastic composition comprising the combination of

[0074] 16. The method of embodiment 15, wherein the aromatic brominated flame retardant is a phenoxy-terminated carbonate oligomer of tetrabromobisphenol A, a homopolymer of dibromostyrene, or poly(2,6-dibromophenoloxide).

[0075] 17. The method of embodiment 15 or 16, wherein the synergist is antimony and / or melamine polyphosphate.

[0076] 18. The method of any one of embodiments 15 to 17, wherein the ratio of aromatic brominated flame retardant to synergist is from about 1:1 to about 3:1.

[0077] 19. The method of any one of embodiments 15 to 18, wherein the thermoplastic polymer is unfilled, the synergist comprises an aliphatic brominated flame retardant, and the ratio of aromatic brominated flame retardant to aliphatic brominated flame retardant is from about 1:1 to about 2:1.

[0078] 20. The method of embodiment 19, wherein the aromatic brominated flame retardant is a phenoxy-terminated carbonate oligomer of tetrabromobisphenol A and the aliphatic brominated flame retardant is a brominated styrene / butadiene block copolymer.

Claims

1. (a) a thermoplastic polyolefin polymer; (b) an aromatic brominated flame retardant that is not decabromodiphenylethane; and (c) a synergist for the aromatic brominated flame retardant and is free of decabromodiphenylethane.

2. 10. The flame retardant thermoplastic composition of claim 1, wherein a molded article of the composition has a thickness of 0.2 mm to 3.2 mm and a UL 94 V0 rating.

3. 3. The flame retardant thermoplastic composition of claim 1, wherein the aromatic brominated flame retardant is a phenoxy-terminated carbonate oligomer of tetrabromobisphenol A, a homopolymer of dibromostyrene, or poly(2,6-dibromophenol oxide).

4. 4. The flame retardant thermoplastic composition of claim 1, wherein the synergist comprises antimony and / or melamine polyphosphate.

5. 5. The flame retardant thermoplastic composition of claim 1, wherein the ratio of the aromatic brominated flame retardant to the synergist is from about 1:10 to 10:

1.

6. 6. The flame retardant thermoplastic composition of claim 1, wherein the aromatic brominated flame retardant is about 5 to 40% by weight of the composition.

7. 7. The flame retardant thermoplastic composition of claim 1, wherein the synergist is from about 1% to about 20% by weight of the composition.

8. 8. The flame retardant thermoplastic composition of any one of claims 1 to 7, further comprising at least one auxiliary process-aid, such as an antioxidant or a heat stabilizer.

9. 9. The flame retardant thermoplastic composition of claim 1, further comprising an inorganic filler.

10. 9. The flame retardant thermoplastic composition of claim 1, wherein the synergist comprises an aliphatic brominated flame retardant.

11. 11. The flame retardant thermoplastic composition of claim 10, wherein the ratio of said aromatic brominated flame retardant to said aliphatic brominated flame retardant is from about 1:1 to about 2:

1.

12. 12. The flame retardant thermoplastic composition of claim 11, wherein the thermoplastic polymer is unfilled.

13. 13. The flame retardant thermoplastic composition of any one of claims 10 to 12, wherein the aromatic brominated flame retardant is a phenoxy-terminated carbonate oligomer of tetrabromobisphenol A and the aliphatic brominated flame retardant is a brominated styrene / butadiene block copolymer.

14. 6. The flame retardant thermoplastic composition of claim 1, wherein the thermoplastic polymer is filled.

15. (a) a thermoplastic polyolefin polymer; (b) an aromatic brominated flame retardant that is not decabromodiphenylethane; and (c) a synergist of the aromatic brominated flame retardant and a method for preparing a flame retardant thermoplastic composition comprising the combination of

16. 16. The method of claim 15, wherein the aromatic brominated flame retardant is a phenoxy-terminated carbonate oligomer of tetrabromobisphenol A, a homopolymer of dibromostyrene, or poly(2,6-dibromophenol oxide).

17. 17. The method of claim 15 or 16, wherein the synergist is antimony and / or melamine polyphosphate.

18. 18. The method of any one of claims 15 to 17, wherein the ratio of the aromatic brominated flame retardant to the synergist is from about 1:1 to 3:

1.

19. 19. The method of any one of claims 15 to 18, wherein the thermoplastic polymer is unfilled, the synergist comprises an aliphatic brominated flame retardant, and the ratio of the aromatic brominated flame retardant to the aliphatic brominated flame retardant is from about 1:1 to about 2:

1.

20. 20. The method of claim 19, wherein the aromatic brominated flame retardant is a phenoxy-terminated carbonate oligomer of tetrabromobisphenol A and the aliphatic brominated flame retardant is a brominated styrene / butadiene block copolymer.

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