Flame retardant polymer composition

Abstract

A flame retardant polymer composition comprising a polymer, a flame retardant, metakaolin, and optionally a reinforcing material, articles made from and including said flame retardant polymer composition, and a method of making said flame retardant polymer composition.

Description

[Technical field]

[0001] The present invention further relates to articles comprising or made from the frame-retardant polymer compositions, as well as methods of making the flame-retardant polymer compositions and articles. [Background technology]

[0002] Flame retardant polymer compositions are widely used, especially where high temperatures and / or fire hazards exist, or where the consequences of burning the polymer composition would be catastrophic. For example, flame retardant polymers may be used in electrical cable sheaths to limit the risk of electrical system failure in the event of a fire, and to limit the risk of fire starting or spreading as a result of cable overheating due to electrical current. Additionally, flame retardant paints may be used as a passive fire protection measure to protect structures.

[0003] Intumescent flame retardant polymer compositions expand as a result of heat exposure, thus leading to a volume increase and density decrease. An important feature of intumescent flame retardant polymer compositions is that they expand significantly when exposed to high temperatures, such as those found during a fire. Some intumescent products can expand more than 100 times their original thickness. As the product expands, it becomes less dense, thus acting as an insulator and limiting the spread of fire.

[0004] Unfortunately, intumescent flame retardant formulations can have melt stability problems and can promote corrosiveness to steel used in processing equipment. It would therefore be desirable to provide alternative and / or improved intumescent flame retardant formulations that overcome these problems but still meet requirements such as UL94 Flame Retardant ratings, total flame time, viscosity, mechanical properties (including stiffness and tensile strength), etc. Summary of the Invention

[0005] According to a first aspect of the present invention, there is provided a flame retardant polymer composition comprising a polymer, a flame retardant, and metakaolin, wherein the flame retardant polymer has a flame retardant rating of V0 as determined by United Laboratories Standard Test 94, 6th Edition when the flame retardant polymer is formed into a layer having a thickness of about 1 / 8 inch or less and about 1 / 128 inch or more. Further, in some embodiments, the flame retardant rating of the composition is V0 as determined by United Laboratories Standard Test 94, 6th Edition when the flame retardant polymer is formed into a layer having a thickness of about 1 / 16 inch or less and about 1 / 64 inch or more. In some embodiments, the flame retardant rating of the composition is V0 as determined by United Laboratories Standard Test 94, 6th Edition when the flame retardant polymer is formed into a layer having a thickness of about 1 / 32 inch or less and about 1 / 64 inch or more.

[0006] In the above embodiments, the metakaolin may have a shape factor of less than 20, optionally 10 or less, or 8 or less, or 5 or less.

[0007] In the above embodiments, the metakaolin may have a soluble alumina content of about 10 wt% to about 30 wt% by weight of the metakaolin, optionally about 14 wt% to about 28 wt%, or about 18 wt% to about 26 wt%, or about 20 wt% to about 26 wt% by weight of the metakaolin. The specified soluble alumina content may be combined or separate with the specified shape factor.

[0008] In the above embodiments, the polymer may be a polyamide. These embodiments may also employ an intumescent flame retardant, which may optionally be an organic phosphinate.

[0009] In embodiments, the flame retardant may be present in an amount of greater than about 10 or 12 or 13 or 14 or 15 wt% and up to 20 or 18 or 17.5 or 16.5 or 16 wt% based on the total weight of the flame retardant polymer composition. The metakaolin may be present in an amount of at least about 1 or 3 or 5 or 7 wt% and up to 20 or 15 or 12 or 10 or 8 wt% based on the total weight of the flame retardant polymer composition.

[0010] The flame retardant polymer compositions described above, when formed into a layer having a thickness of about 1 / 32 inch or less and about 1 / 64 inch or more, may have a total burn time, as determined by United Laboratories Standard Test 94, 6th Edition, of less than 50 seconds, or more typically less than 40 seconds, or less than 30 seconds, or for a thickness of about 1 / 64 inch, less than 50 seconds or more typically less than 40 seconds.

[0011] The flame retardant polymer compositions described may have an average molecular weight that is at least 3%, or optionally at least 5% or at least about 10% or at least about 15% or at least about 20% or at least about 30% or at least about 40% greater than the average molecular weight of an otherwise identical flame retardant polymer composition that contains the same amount of a mineral additive or reinforcing additive different from metakaolin.

[0012] The flame retardant polymer compositions described may have an intrinsic viscosity that is at least 3 ml / g, or optionally at least 4 ml / g or at least about 5 ml / g or at least about 7 ml / g greater than the intrinsic viscosity number of an otherwise identical flame retardant polymer composition that contains the same amount of a mineral additive or reinforcing additive different from metakaolin.

[0013] The flame retardant polymer compositions described may have improved corrosion resistance when compared to otherwise identical flame retardant polymer compositions that contain the same amount of a mineral additive or reinforcing additive different from metakaolin.

[0014] In embodiments, all of the flame retardant polymer compositions described may include a reinforcing additive present in an amount of about 10 wt% to about 40 wt%. For these embodiments, the combined amount of metakaolin and reinforcing additive in the composition may be up to 20 wt%, or 30 wt%, or 40 wt%, or 50 wt%, based on the total weight of the composition. In some of these embodiments, the reinforcing additive will be selected from glass fiber, wollastonite, talc, mica, magnesium oxysulfate, carbon fiber, hydrous kaolin having a shape factor greater than 20 (or optionally 60 or greater), calcined kaolin, and combinations thereof.

[0015] In another embodiment, there is an article comprising the above-mentioned substrate material and the flame retardant polymer composition. For example, the substrate material may be an electrical cable, an electrical or electronic component, or an automotive component, and the substrate material is made of or coated with the flame retardant polymer composition.

[0016] For example, a flame retardant polymer composition coated on a substrate may include a polymer, a flame retardant, and metakaolin, and the flame retardant polymer composition may be coated on a substrate to form a layer. When the flame retardant polymer is formed into a layer having a thickness of about 1 / 8 inch or less and about 1 / 128 inch or more, the flame retardant rating is V0 as determined by United Laboratories Standard Test 94, 6th Edition. When the flame retardant polymer is formed into a layer having a thickness of about 1 / 16 inch or less and about 1 / 64 inch or more, the flame retardant rating is V0 as determined by United Laboratories Standard Test 94, 6th Edition. When the flame retardant polymer is formed into a layer having a thickness of about 1 / 32 inch or less and about 1 / 64 inch or more, the flame retardant rating of the composition is V0 as determined by United Laboratories Standard Test 94, 6th Edition.

[0017] For example, the metakaolin used in the flame retardant polymer composition of the article may have a shape factor of less than 20, optionally not greater than 10, or not greater than 8, or not greater than 5. In addition to or separate from the shape factor, the metakaolin may have a soluble alumina content of from about 10 wt% to about 30 wt% by weight of the metakaolin, optionally from about 14 wt% to about 28 wt%, or from about 18 wt% to about 26 wt%, or from about 20 wt% to about 26 wt% by weight of the metakaolin.

[0018] For example, the polymer may be a polyamide and / or the flame retardant may be an intumescent flame retardant, which may optionally be an organic phosphinate. Further, the flame retardant may be present in an amount of greater than about 10 or 12 or 13 or 14 or 15 wt% and not more than 20 or 18 or 17.5 or 16.5 or 16 wt% based on the total weight of the flame retardant polymer composition. The metakaolin may be in an amount of at least about 1 or 3 or 5 or 7 wt% and not more than 20 or 15 or 12 or 10 or 8 wt% based on the total weight of the flame retardant polymer composition.

[0019] For example, when the flame retardant polymer composition is coated on an article, the total burn time may be less than 50 seconds, or more typically less than 40 seconds, or less than 30 seconds, as determined by United Laboratories Standard Test 94, 6th Edition, when formed into a layer having a thickness of about 1 / 32 inch or less and about 1 / 64 inch or more, or for a thickness of about 1 / 64 inch, less than 50 seconds or more typically less than 40 seconds.

[0020] For example, the described flame retardant polymer compositions may have an average molecular weight that is at least 3%, or optionally at least 5% or at least about 10% or at least about 15% or at least about 20% or at least about 30% or at least about 40% greater than the average molecular weight of an otherwise identical flame retardant polymer composition that contains the same amount of a mineral additive or reinforcing additive different from metakaolin.

[0021] For example, the described flame retardant polymer compositions may have an intrinsic viscosity that is at least 3 ml / g, or optionally at least 4 ml / g or at least about 5 ml / g or at least about 7 ml / g greater than the intrinsic viscosity number of an otherwise identical flame retardant polymer composition that contains the same amount of a mineral additive or reinforcing additive different from metakaolin.

[0022] For example, an article incorporating the flame retardant polymer composition may have improved corrosion resistance when compared to an otherwise identical flame retardant polymer composition that contains the same amount of a mineral additive or reinforcing additive different from metakaolin.

[0023] In the described articles, the flame retardant polymer composition may include a reinforcing additive present in an amount of about 10 wt% to about 40 wt%. For these embodiments, the combined amount of metakaolin and reinforcing additive in the composition may be up to 20 wt%, or 30 wt%, or 40 wt%, or 50 wt%, based on the total weight of the composition. In some of these embodiments, the reinforcing additive will be selected from glass fiber, wollastonite, talc, mica, magnesium oxysulfate, carbon fiber, hydrous kaolin having a shape factor greater than 20 (or optionally 60 or greater), calcined kaolin, and combinations thereof. [Brief description of the drawings]

[0024] The present disclosure and various aspects are illustrated in the following detailed description and accompanying figures.

[0025] [Figure 1] FIG. 1 is a graph showing the Flexural Modulus of various compositions defined in Example 1.

[0026] [Diagram 2] FIG. 2 is a graph showing the Flexural Strength of various compositions defined in Example 1.

[0027] [Diagram 3] FIG. 3 is a graph showing the Notched Izod Impact at 23° C. of various compositions defined in Example 1.

[0028] [Figure 4] FIG. 4 is a graph showing the Tensile Modulus of various compositions defined in Example 1.

[0029] [Diagram 5] FIG. 5 is a graph showing the tensile strength of various compositions defined in Example 1.

[0030] [Figure 6] FIG. 6 is a graph showing the Tensile Elongation of various compositions defined in Example 1.

[0031] [Figure 7] FIG. 7 is a graph showing the UL94 FR Rating of various compositions as defined in Example 1.

[0032] [Figure 8] FIG. 8 is a graph showing the UL94 FR - Total Flame Time for various compositions as defined in Example 1.

[0033] [Figure 9] FIG. 9 contains photographs showing a visual comparison of the corrosion effects for the various formulations defined in Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Certain embodiments and / or disclosures of the present invention are described in more detail below. In case of conflict with terms and / or definitions incorporated by reference, the terms and definitions provided herein control.

[0035] As used herein, the terms "comprises," "comprising," or any other variations thereof, are intended to include a non-exclusive inclusion, such that a process, method, composition, article, or device that includes a list of elements not only includes those elements, but may also include other elements not expressly recited or inherent to such process, method, composition, article, or device. The term "exemplary" is used in the sense of "example" rather than "ideal."

[0036] As used herein, the singular forms "a," "an," and "the" include plural references unless the context dictates otherwise. The terms "approximately" and "about" refer to being approximately the same as a referenced numerical value or value. As used herein, the terms "approximately" and "about" should be understood to include ±5% of the stated amount or value.

[0037] Disclosed herein is a flame retardant polymer composition comprising a polymer, a flame retardant, metakaolin, and optionally a reinforcing additive. The flame retardant polymer composition may, for example, consist of or essentially consist of a polymer, a flame retardant, metakaolin, and optionally a reinforcing additive. The term "consisting essentially of" excludes additional elements, steps, or ingredients not expressly mentioned, unless the additional elements, steps, or ingredients materially affect the basic and novel properties of the invention. For example, "consisting essentially of" does not exclude trace amounts of materials that do not affect the properties of the claimed compound.

[0038] Each of the components of the flame retardant polymer composition disclosed herein can be present in any amount within the ranges specified herein, provided that the total wt% of the flame retardant polymer composition is 100 wt%.

[0039] The polymer may be, for example, a thermoplastic polymer. The polymer may be, for example, present in the form of a polymer matrix. The other components of the flame retardant polymer composition (e.g., flame retardant, high aspect ratio particulate mineral, optional reinforcing additives) are dispersed in the polymer matrix. The polymer may be, for example, a thermoplastic olefin, polyamide (including, but not limited to, Nylon PA6, Nylon 66, Nylon 46, Nylon 4T, Nylon 6T, Nylon 6 / 10, Nylon 9T, Nylon 10T, Nylon 11T, and Nylon 12), polyester (including, but not limited to, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polylactic acid, and polybutylene succinate), acrylonitrile butadiene styrene (ABS), polymethyl methacrylate (PMMA), thermoplastic elastomer (TPE), thermoplastic polyurethane (TPU), polyphthalamide (PPA), polyoxymethylene (POM), polyvinyl chloride (PVC), polystyrene (PS), polyphenylene ether (PPE - also known as polyphenylene oxide (PPO)), and blends thereof. The polymer may be, for example, a polyalkylene (e.g., polyethylene, polypropylene, or polybutylene), a polyvinyl ester (of the general formula -[RCOOCHCH2]-), a polystyrene, polyvinyl chloride, polyvinyl acetate, polyvinyl alcohol, polyacrylonitrile, acrylonitrile butadiene styrene, a polyamide, polylactic acid, polybutylene terephthalate, polyethylene terephthalate, polycarbonate, polyvinyl acetate (e.g., ethylene vinyl acetate or poly(meth methacrylate)), or a combination of two or more thereof. In certain embodiments, the polymer is one or more polyamides.

[0040] Broadly, the polymer may be present in the flame retardant polymer composition in an amount of about 30 wt% to about 80 wt%, based on the total weight of the flame retardant polymer composition. More typically, the polymer may be present in the flame retardant polymer composition in an amount of at least about 35 wt%, or at least about 40 wt%, or at least about 55 wt%, based on the total weight of the flame retardant polymer composition. Still more typically, the polymer may be present in the flame retardant polymer composition in an amount of up to about 75 wt%, or up to about 70 wt%, or up to about 65 wt%, or up to about 60 wt%, or up to about 55 wt%, or up to about 50 wt%, based on the total weight of the flame retardant polymer composition. As will be understood, the range of the amount of the polymer in the flame retardant polymer composition may be any combination of lower and upper limits, for example, the polymer may be present in the flame retardant polymer composition in an amount ranging from about 40 wt% to about 80 wt%, or from about 40 wt% to about 50 wt%, based on the total weight of the flame retardant polymer composition.

[0041] The term "flame retardant" refers to a chemical that, when added to a polymer, can prevent fire, inhibit or slow the spread of fire, and / or limit the damage caused by fire. Flame retardants may work, for example, by one or more of endothermic degradation, thermal shielding, gas phase dilution, and gas phase radical quenching. Flame retardants that work by endothermic degradation remove heat from the substrate, thereby cooling the material. Flame retardants that work by thermal shielding create an insulating barrier between the burning and non-burning parts of the material, for example by forming char, which separates the flame from the material and slows the transfer of heat to the non-burning material. Flame retardants that work by gas phase dilution produce inert gases (e.g., carbon dioxide and / or water) by pyrolysis, thus diluting the flammable gases, thereby reducing the partial pressure of the flammable gases and oxygen and slowing the reaction rate. Flame retardants that work by gas-phase radical quenching release substances that react with H and OH radicals in flames, such as hydrogen chloride and hydrogen bromide, to form less reactive radicals (such as Cl and Br radicals), making them much less capable of enhancing radical oxidation reactions. In certain embodiments, the flame retardant used in the flame-retardant polymer composition disclosed herein is an intumescent flame retardant. This refers to a flame retardant that can expand as a result of heat exposure, thus increasing its volume and decreasing its density. Intumescent flame retardants may produce char during combustion, which can act as a thermal barrier between burning and non-burning materials.

[0042] Although the benefits of the present invention can be achieved with compositions using other flame retardants, typically the compositions will hereinafter use intumescent flame retardants, and more typically the compositions will hereinafter use organic phosphinate flame retardants.

[0043] The flame retardant may be a halogenated or non-halogenated composition, such as tetrabromobisphenol A (TBBA), dodecahlorepentacyclooctadecadiene (Dechlorane), decabromodiphenyl ether (Deca), hexabromocyclododecane (HBCD), tetrabromophthalic anhydride and synergist (antimony trioxide), and combinations thereof. For example, the flame retardant may be a non-halogenated composition, such as polyphosphates, phosphinic acid derivatives, red phosphorus, ammonium polyphosphate (APP) and triaryl phosphate, melamine cyanurate, melamine polyphosphate, magnesium hydroxide and aluminum hydroxide, and combinations thereof.

[0044] The intumescent flame retardant useful in the composition may be a phosphorus and / or nitrogen-containing compound; for example, red phosphorus, a phosphate, a polyphosphate (e.g., melamine polyphosphate), a phosphonate (e.g., dimethyl methylphosphonate (DMMP)), a phosphinate (e.g., aluminum diethylphosphinate), a halogenated organic phosphate (e.g., tris(1,3-dichloro-2-propyl)phosphate, tetrakis(2-chloroethyl)dichloroisoentyl diphosphate), a phosphazene, a polyphosphazene, a triazine (e.g., melamine cyanurate), an organic phosphate (e.g., triphenyl phosphate (TPP), resorcinol bis(diphenyl phosphate) (RDP), bisphenol A diphenyl phosphate (BADP), tricresyl phosphate (TCP)), or one or more combinations thereof. In certain embodiments, the phosphorus-containing compound is an organic phosphate, an organic phosphinate, a halogenated organic phosphate, or one or more combinations thereof.

[0045] The flame retardant may be present in the flame retardant polymer composition in an amount of at least about 10 wt%, for example, based on the total weight of the flame retardant polymer composition. For example, the flame retardant may be present in the flame retardant polymer composition in an amount of at least about 10 wt%, or at least about 12 wt%, or at least about 13 wt%, or at least about 14 wt%, or at least about 15 wt%, or at least about 16 wt%, based on the total weight of the flame retardant polymer composition.

[0046] The flame retardant may be present in the flame retardant polymer composition in an amount of up to about 40 wt%, but more typically in an amount of up to about 20 wt%, based on the total weight of the flame retardant polymer composition. For example, the flame retardant may be present in the flame retardant polymer composition in an amount of up to about 20 wt%, or up to about 18 wt%, or up to about 17.5 wt%, or up to about 16.5 wt%, or up to about 16 wt%, based on the total weight of the flame retardant polymer composition.

[0047] The flame retardant polymer composition includes metakaolin herein. Metakaolin may be produced from kaolin (Al2Si2O5(OH)4), hereafter referred to as hydrous kaolin. Hydrous kaolin includes the minerals kaolinite, dickite, nacrite and halloysite. Hydrous kaolin clay may be a processed material derived from natural sources, i.e., unrefined natural kaolin clay minerals. Processed kaolin clay may typically contain at least about 50% by weight kaolinite. For example, most commercially available processed kaolin clays contain more than about 75% by weight kaolinite, and may contain more than about 90% by weight, and in some cases more than about 95% by weight kaolinite.

[0048] Methods of making metakaolin may include calcining hydrous kaolin (typically in the form of kaolin clay) at a suitable temperature for a suitable time. The temperature and time may be sufficient to remove some of the moisture content from the kaolin. In some examples, methods of making metakaolin include calcining the kaolin at a temperature ranging from about 500° C. to about 900° C., e.g., from about 550° C. to about 850° C., from about 600° C. to about 800° C., from about 650° C. to about 750° C., or from about 680° C. to about 720° C. In some examples, methods of making metakaolin may include calcining the kaolin for a time ranging from about 30 minutes to about 120 minutes, from about 40 minutes to about 110 minutes, from about 50 minutes to about 100 minutes, from about 60 minutes to about 90 minutes, from about 50 minutes to about 70 minutes, or from about 80 minutes to about 110 minutes. Such conditions may result in a metakaolin having a shape factor of 50 or less, and a soluble alumina content of about 10 wt% to about 30 wt%, based on the total weight of the metakaolin. More typically, however, such conditions may be used to result in a metakaolin having a shape factor of less than 20, or about 10 or less, or about 8 or less, or about 5 or less. Such conditions may also be used to result in a metakaolin having any of the aforementioned shape factors, and a soluble alumina content of about 10% to about 30%, or about 14 wt% to about 30 wt%, or about 14 wt% to about 28 wt%, or about 18 wt% to about 30 wt%, or about 18 wt% to about 28 wt%, or about 18 wt% to about 26 wt%, or about 20 wt% to about 26 wt%, based on the total weight of the metakaolin. Both the shape factor and the soluble alumina content are discussed further below.

[0049] Calcining hydrous kaolin at temperatures above 900°C, and perhaps for longer periods (>120 minutes) below 900°C, produces what may be referred to as "calcined kaolin" or "spinel kaolin." Essentially, further heating causes conversion to an aluminum-silicon spinel, which is sometimes referred to as a gamma-alumina type structure. Furthermore, heating at even higher temperatures may nucleate the spinel phase, which transforms into platelet mullite and highly crystalline cristobalite. This nucleated phase is also included herein under the term "calcined kaolin." Metakaolin, although calcined, is not included in the term "calcined kaolin."

[0050] As will be appreciated, metakaolin is a different phase than either hydrous kaolin or calcined kaolin, for example, metakaolin has a different shape factor and a higher soluble alumina content than hydrous kaolin, and a higher soluble alumina content than calcined kaolin.

[0051] As used herein, the term "shape factor" refers to a measurement of the average ratio (based on a weight average) of the average particle diameter to particle thickness for a population of particles of various sizes and shapes. Shape factor can be measured using the electrical conductivity method and apparatus described in U.S. Pat. No. 5,576,617 (also called PANACEA (Particle Assessment by Natural Alignment (and) Conductivity Effect Analysis)). In this method, the electrical conductivity of a fully dispersed aqueous suspension of particles is measured as they flow through an elongated tube.

[0052] Conductivity measurements are made between (a) a pair of electrodes separated from each other along the long axis of the tube, and (b) a pair of electrodes separated from each other across the transverse width of the tube. The difference between these two conductivity measurements determines the shape factor of the particulate material. A higher shape factor generally indicates a more plate-like material.

[0053] Metakaolin, as used herein, will have a smaller shape factor than the hydrous kaolin from which it is formed. Typically, metakaolin, as used herein, may have a shape factor of less than about 20. However, in more typical embodiments, metakaolin may have a shape factor of 10 or less, and may have a shape factor of 8 or less, or 5 or less. Generally, a lower limit for the shape factor need not be stated, but for completeness, metakaolin may have a shape factor of at least 1. Metakaolin is generally not considered a high aspect ratio or high shape factor material; whereas plate-like hydrous kaolin may take the form of what is considered a high aspect ratio or high shape factor material.

[0054] The use of metakaolin has advantages over the use of other mineral additives (e.g., hydrotalcite, wollastonite, mica, talc, hydrous kaolin, and / or calcined kaolin), but is particularly preferred over the use of such other mineral additives having high aspect ratios, such as hydrous kaolins having shape factors of about 20, and more typically 60 or greater.

[0055] Soluble alumina content is an indicator of the reactivity of a material. The present disclosure recognizes the discovery that materials having higher soluble alumina contents yield different properties when used in flame retardant polymer compositions than materials having lower soluble alumina contents.

[0056] The amount of soluble alumina content may be measured using nitric acid. In an exemplary method, 100 milligrams of sample are measured using an analytical balance and transferred to a 16 mm x 150 mm test tube with a screw-on cap. 10 mL of concentrated nitric acid is added to the test tube, which is loosely capped. The test tube is then heated in a water bath (temperature of 100°C ± 2°C) for 4 hours and allowed to cool. The top portion of the test tube is filled with deionized water, and the solution in the test tube is then filtered with ashless filter paper into a 100 mL volumetric flask. A control sample is also prepared using concentrated nitric acid. The flask is then filled to the 100 mL mark, and the solution is analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-AES) using various dilutions of a 1000 ppm aluminum standard solution as the standard. The soluble alumina content is then calculated using the following equation:

number

[0057] The metakaolin used in the composition generally has a soluble alumina content of at least about 10% by weight based on the total weight of the metakaolin. In some embodiments, the soluble alumina content is at least about 12% by weight, or at least about 14% by weight, or at least about 16% by weight, or at least about 18% by weight based on the total weight of the metakaolin. Generally, the soluble alumina content may be up to 30% by weight based on the total weight of the metakaolin, but may be up to 28%, or up to 26%, or up to 24%. For example, the soluble alumina content ranges from about 10% to about 30%, or from about 114% to about 30%, or from about 14% to about 28%, or from about 18% to about 30%, or from 18% to 28%, or from about 18% to about 26%, or from about 20% to about 26% by weight based on the total weight of the metakaolin.

[0058] For comparison, typical hydrous kaolin and calcined kaolin contain less than 10 wt% soluble alumina content, with a typical amount being about 0.5 wt% to 6 wt%, based on the total hydrous or calcined kaolin. Thus, as will be understood, metakaolin is distinct from either hydrous or calcined kaolin. While several embodiments of the present disclosure include the addition of hydrous or calcined kaolin to the flame retardant polymer composition, such embodiments require the presence of metakaolin. Thus, any hydrous or calcined kaolin in the flame retardant polymer composition disclosed herein is in addition to metakaolin, and not a replacement for metakaolin.

[0059] According to some embodiments of the present disclosure, the flame retardant composition comprises at least about 1 wt%, or at least about 3 wt%, or at least about 7 wt% metakaolin based on the total weight of the composition. Typically, the metakaolin is present in an amount of less than 40 wt%, but more typically, the metakaolin is present in an amount of less than 20 wt%, based on the total weight of the composition. In some embodiments, the metakaolin is present in an amount of less than 15 wt%, or less than 12 wt%, or less than 10 wt%, or less than 8 wt%, based on the total weight of the composition. The above upper and lower limits may be any combination, such as 1 wt% to 15 wt%, or 1 wt% to 12 wt%, or 1 wt% to 10 wt%, or 1 wt% to 8 wt%, or 3 wt% to 15 wt%, etc.

[0060] As indicated above, the flame retardant polymer composition may optionally include a reinforcing additive. The terms "reinforcing additive" and "reinforcing material" are used interchangeably herein and refer to any material that can reinforce (e.g., improve) the tensile and flexural modulus and / or tensile and flexural strength of the polymer composition.

[0061] The reinforcing material or additive may be, for example, wollastonite, talc, mica, hydrous kaolin, calcined kaolin, magnesium oxysulfate, and / or reinforcing fiber. The reinforcing fiber may be, for example, glass fiber, carbon fiber, aramid fiber (e.g., Kelvar®, Nomex®, Technora®), wood fiber, basalt fiber, or one or more combinations thereof. In certain embodiments, the reinforcing material is selected from glass fiber, wollastonite, talc, mica, carbon fiber, or combinations thereof. In certain embodiments, the reinforcing material is selected from glass fiber, carbon fiber, or combinations thereof.

[0062] Hydrous kaolin or calcined kaolin reinforced materials will typically have a shape factor (as discussed above) of greater than 20, more typically greater than or equal to 60. Additionally, talc, mica and wollastonite are also well-known high aspect ratio materials.

[0063] The reinforcing fibers may, for example, be wound into threads having a larger diameter than the fibers before being incorporated into the flame retardant polymer composition. The reinforcing fibers (e.g., glass fibers or carbon fiber filaments) may, for example, have a diameter in the range of about 6 μm to about 20 μm. For example, the reinforcing fibers (e.g., glass fibers) may have a diameter in the range of about 6 μm to about 19 μm, or about 6 μm to about 18 μm, or about 6 μm to about 17 μm, or about 6 μm to about 16 μm, or about 6 μm to about 15 μm, or about 6 μm to about 14 μm. For example, the reinforcing fibers (e.g., glass fibers) may have a diameter in the range of about 6.5 μm to about 13.5 μm, or about 7 μm to about 13 μm, or about 7.5 μm to about 12.5 μm, or about 8 μm to about 12 μm, or about 8.5 μm to about 11.5 μm, or about 9 μm to about 11 μm. The reinforcing fibers (e.g., glass fibers or carbon fiber filaments) may have a length in the range of, for example, about 3 mm to about 8 mm. For example, the reinforcing fibers (e.g., glass fibers) may have a length in the range of about 3 mm to about 5 mm, or about 3.5 mm to about 7.5 mm, or about 4 mm to about 7 mm, or about 4.5 mm to about 6.5 mm, or about 5 mm to about 6 mm.

[0064] The carbon fibers may be bundled such that each bundle contains about 1000 to about 100,000 carbon fiber filaments. For example, each bundle may contain about 2000 to about 80,000, or about 3000 to about 50,000, or about 4000 to about 25,000, or about 5000 to about 20,000 carbon fiber filaments.

[0065] If present, the reinforcing material may be present in the flame retardant polymer composition in an amount of, for example, at least about 1 wt%, based on the total weight of the flame retardant polymer composition. For example, the reinforcing material may be present in the flame retardant polymer composition in an amount of at least about 5 wt%, or at least about 10 wt%, or at least about 12 wt%, or at least about 15 wt%, or at least about 18 wt%, or at least about 20 wt%, or at least about 22 wt%, or at least about 25 wt%, or at least about 28 wt%, based on the total weight of the flame retardant polymer composition.

[0066] When present, the reinforcing material may be present in the flame retardant polymer composition in an amount of, for example, up to about 50 wt%, based on the total weight of the flame retardant polymer composition. For example, the reinforcing material may be present in the flame retardant polymer composition in an amount of up to about 45 wt%, or up to about 40 wt%, or up to about 38 wt%, or up to about 36 wt%, or up to about 35 wt%, or up to about 34 wt%, or up to about 32 wt%, based on the total weight of the flame retardant polymer composition.

[0067] For example, the reinforcing material may be present in the flame retardant polymer composition in an amount ranging from about 1 wt% to about 50 wt%, or from about 5 wt% to about 45 wt%, or from about 10 wt% to about 40 wt%, or from about 15 wt% to about 35 wt%, or from about 28 wt% to about 32 wt%, based on the total weight of the flame retardant polymer composition.

[0068] Generally, when a reinforcing additive is used, the total amount of metakaolin and reinforcing additive in the composition will be up to 50 wt%, based on the total weight of the flame retardant polymer composition. For example, the total amount of metakaolin and reinforcing additive may be up to 40 wt%, or up to 30 wt%, or up to 20 wt%, based on the total weight of the flame retardant polymer composition. Furthermore, the total amount of metakaolin and reinforcing additive will generally be at least 2 wt%, based on the total weight of the flame retardant polymer composition. More typically, the total amount will be at least 11 wt%, or at least 13 wt%, or at least 15 wt%, based on the total weight of the flame retardant polymer composition. For example, the total amount may be 11 wt% to 50 wt%, or 15 wt% to 40 wt%.

[0069] The flame retardant polymer composition may, for example, include further additives. For example, the flame retardant polymer composition may further include one or more of coupling agents (e.g., maleic anhydride grafted polyolefins), compatibilizers (e.g., maleic anhydride grafted polyolefins), opacifiers, pigments, colorants, antioxidants, anti-fog agents, antistatic agents, moisture barrier additives, gas barrier additives, dispersants, hydrocarbon waxes, stabilizers, co-stabilizers, lubricants, agents for improving tenacity, agents for improving heat-and-form stability, agents for improving processing performance, process aids (e.g., Polybatch® AMF-705), mold release agents (e.g., fatty acids, zinc salts, calcium salts, magnesium salts, lithium salts of fatty acids, organic phosphate esters, stearic acid, zinc stearate, calcium stearate, magnesium stearate, lithium stearate, calcium oleate, zinc palmiate), antioxidants, and plasticizers.

[0070] Each of the additional additives may be present independently in the flame retardant polymer composition. Each of the additional additives may be present in the flame retardant polymer composition in an amount ranging from more than 0 wt%, more typically more than 0.1 wt%, or at least 0.2 wt%, or at least 0.5 wt%, or at least 1 wt%, or at least 1.5 wt%, or at least 2 wt%, based on the total weight of the flame retardant polymer composition. The flame retardant polymer composition may, for example, comprise about 10 wt% or less, or about 5 wt% or less, or 4 wt% or less, or 3 wt% or less of the additional additive based on the total weight of the flame retardant polymer composition.

[0071] Typically, the mineral additive in the flame retardant polymer composition causes a decrease in the intrinsic viscosity (as measured by the ISO 307 standard) compared to an otherwise identical flame retardant polymer composition without the mineral additive ("neat composition"). However, it has been found that the use of metakaolin advantageously results in a smaller decrease in the intrinsic viscosity than other mineral additives, such as hydrotalcite, mica, hydrous kaolin. Thus, a flame retardant polymer composition containing metakaolin may have an intrinsic viscosity that is at least about 7 ml / g, or at least about 5 ml / g, or at least 4 ml / g, or at least 3 ml / g greater than the intrinsic viscosity of an otherwise identical flame retardant polymer composition containing a similar or the same amount of a different mineral additive, such as hydrotalcite, wollastonite, mica, talc, hydrous kaolin, and / or calcined kaolin.

[0072] Furthermore, the use of metakaolin can improve the average MW (molecular weight as measured by gel permeation chromatography). For example, the average MW can be similar or higher for a similar formulation using hydrotalcite instead of metakaolin. A flame-retardant polymer composition containing metakaolin can have an average MW that is at least about 40%, or at least about 30%, or at least about 20%, or at least about 15%, or at least about 10%, or at least about 5%, or at least about 3% higher than the average MW of an otherwise identical flame-retardant polymer composition that does not contain metakaolin or contains a similar amount of a different mineral additive, such as hydrotalcite, wollastonite, mica, talc, hydrous kaolin, and / or calcined kaolin. Without wishing to be bound by theory, it is currently believed that metakaolin slows the decomposition of the resin / polymer during processing; thus helping to maintain a higher MW. This can also help to produce a higher viscosity number.

[0073] Furthermore, the flame retardant polymer composition retains excellent mechanical properties. For example, the flame retardant polymer composition may have a flexural modulus in the range of about 5000 MPa to about 15,000 MPa. The flexural modulus may be measured, for example, by ISO 178 (at 64 mm span and 2 mm / min speed). For example, the flame retardant polymer composition may have a tensile modulus in the range of about 5000 MPa to about 16,000 MPa. The tensile modulus may be measured, for example, by ISO 527 (type 1A) (at 5 mm / min speed). For example, the flame retardant polymer composition may have a tensile strength in the range of about 50 MPa to about 200 MPa. The tensile strength may be measured, for example, by ISO 527 (type 1A) (at 5 mm / min speed). For example, the flame retardant polymer composition may have a tensile elongation in the range of about 1% to about 15%. The tensile elongation may be measured, for example, by ISO 527 (Type 1A) (at a rate of 5 mm / min). For example, the flame retardant polymer composition has a tensile elongation of about 3 kJ / m 2 ~about 20 kJ / m 2The ISO notched Izod impact is measured at 23°C according to ISO 180. The flame retardant polymer composition may have an ISO notched Izod impact in the range of about 30 J / m 2 ~about 200 J / m 2 The material may have an ASTM notched Izod impact in the range of 0.1 to 0.5 mm, as measured at 23° C. by ASTM D256.

[0074] Further provided herein is an article made from or including the flame retardant polymer composition according to any aspect or embodiment disclosed herein. The article may include a substrate material and a flame retardant polymer composition. For example, the substrate material may be made from the flame retardant polymer composition, or optionally, the substrate may be coated with the flame retardant polymer composition. For example, the flame retardant polymer composition may be formed or deposited as a layer on at least a portion of the substrate material. The article may be, for example, an automobile part, such as an automobile body part, a bumper, a door panel, a pipe, a dashboard, a wheel cover, an instrument housing, a display panel, or an engine cover. For example, a metal pipe may be coated with the flame retardant polymer composition, or a metal bumper may be coated with the flame retardant polymer composition. The article may be, for example, a cable (e.g., an electrical cable) coated with the flame retardant polymer composition disclosed herein. The article may be an electrical or electronic component. The article may be, for example, an electrical connector. The article may be, for example, a housing for autonomous driving and / or electronic applications.

[0075] When the flame retardant polymer composition is formed into a layer on an article such as those described herein, the flame retardant polymer composition may have a flame retardant rating of V2 or V1 or higher when measured using United Laboratories Standard Test 94, 6th Edition (UL94). For example, the flame retardant polymer composition may have a flame retardant rating of V0 or higher when measured using the UL94 standard. The flame retardant rating may be measured, for example, using a composition having a thickness of 1 / 8 inch (about 3 mm), 1 / 16 inch (about 1.5 mm), and / or 1 / 32 inch (about 0.8 mm).

[0076] When the flame retardant polymer composition is formed into a layer having a thickness of 1 / 8 inch (about 3 mm) or less and about 1 / 128 inch (0.2 mm) or more, the flame retardant polymer composition may have a flame retardant rating of, for example, V0, where the flame retardant rating of the composition is V0 as determined by United Laboratories Standard Test 94, 6th Edition. For example, when the flame retardant polymer is formed into a layer having a thickness of about 1 / 16 inch (1.5 mm) or less and about 1 / 64 inch (0.4 mm) or more, the flame retardant rating of the composition is V0 as determined by United Laboratories Standard Test 94, 6th Edition. For example, when the flame retardant polymer is formed into a layer having a thickness of 1 / 32 inch (0.8 mm) or less and about 1 / 64 inch or more, the flame retardant rating of the composition is V0 as determined by United Laboratories Standard Test 94, 6th Edition.

[0077] When the flame retardant polymer composition comprises about 10 wt% or more of a flame retardant and about 1 wt% or more of metakaolin, and is measured using the UL94 standard at a thickness of at least 1 / 64 inch (0.4 mm), and optionally 1 / 8 inch (3 mm) or less, or 1 / 16 inch (1.5 mm) or less, 1 / 32 (0.8 mm) or less, the flame retardant polymer composition may have a flame retardant rating of, for example, V0. The flame retardant polymer composition may comprise, for example, about 10 wt% to about 20 wt% of a flame retardant and 1 wt% to 20 wt% of metakaolin. Optionally, the polymer composition may comprise, for example, about 10 wt% to about 40 wt% of a reinforcing material (e.g., glass fiber).

[0078] When the flame retardant polymer composition comprises about 12 wt% or more of a flame retardant and about 5 wt% or more of metakaolin, and is measured using the UL94 standard at a thickness of at least 1 / 64 inch (0.4 mm), and optionally 1 / 8 inch (3 mm) or less, or 1 / 16 inch (1.5 mm) or less, 1 / 32 (0.8 mm) or less, the flame retardant polymer composition may have a flame retardant rating of, for example, V0. The flame retardant polymer composition may comprise, for example, about 12 wt% to about 18 wt% of a flame retardant and 5 wt% to about 15 wt% of metakaolin. Optionally, the polymer composition may comprise, for example, about 10 wt% to about 40 wt% of a reinforcing material (e.g., glass fiber).

[0079] When the flame retardant polymer composition comprises about 15 wt% or more of a flame retardant and about 7 wt% or more of metakaolin, and is measured using the UL94 standard at a thickness of at least 1 / 64 inch (0.4 mm), and optionally 1 / 8 inch (3 mm) or less, or 1 / 16 inch (1.5 mm) or less, 1 / 32 (0.8 mm) or less, the flame retardant polymer composition may have a flame retardant rating of, for example, V0. The flame retardant polymer composition may comprise, for example, about 15 wt% to about 17.5 wt% of a flame retardant and about 7 wt% to about 12 wt% of metakaolin. Optionally, the polymer composition may comprise, for example, about 10 wt% to about 40 wt% of a reinforcing material (e.g., glass fiber).

[0080] The flame retardant polymer compositions disclosed herein, when formed into a layer having a thickness of about 1 / 32 inch or less, about 1 / 64 inch or more, such as on a substrate as described herein, will typically have a total flame time of the composition as determined by United Laboratories Standard Test 94, 6th Edition, of less than 50 seconds, or more typically less than 40 seconds, or less than 30 seconds, or for a thickness of about 1 / 64 inch, less than 50 seconds, or more typically less than 40 seconds.

[0081] The flame retardant polymer composition may have, for example, a limiting oxygen index (LOI) in the range of about 24% to about 38%. For example, the flame retardant polymer composition may have a LOI in the range of about 23% to about 37%, or about 24% to about 36%, or about 25% to about 35%, or about 26% to about 34%, or about 27% to about 34%, or about 28% to about 33%. The limiting oxygen index (LOI) may be measured, for example, by ISO 4589 and / or ASTM D2863 testing.

[0082] The flame retardant polymer composition may have a flame retardant rating equal to or greater than the flame retardant rating of a comparative composition that is identical except that it does not contain metakaolin, as may be measured, for example, by the UL 94 standard.

[0083] A flame retardant polymer composition may, for example, have a flame retardant rating equal to or greater than the flame retardant rating of a comparative composition that is identical except that it contains a similar or equal amount of hydrous kaolin or calcined kaolin instead of metakaolin.

[0084] Furthermore, the flame retardant composition has improved corrosion resistance when compared to a comparative composition that is otherwise identical but does not contain metakaolin. Furthermore, the flame retardant polymer composition has improved corrosion resistance when compared to a comparative composition that is otherwise identical but contains a similar or the same amount of hydrous kaolin, calcined kaolin, reinforcing additives, or combinations thereof, instead of metakaolin. For example, as described herein, when deposited on a substrate material to produce an article, a substrate material having a layer of the flame retardant polymer composition will exhibit less corrosion over time than an identical substrate material having a layer of the flame retardant polymer composition that is otherwise identical but contains the same amount of mineral additives (e.g., hydrotalcite, wollastonite, mica, talc, hydrous kaolin, and / or calcined kaolin) different from metakaolin.

[0085] Further provided herein is a method of making a flame retardant polymer composition according to any aspect or embodiment disclosed herein, which may include, for example, mixing a polymer, a flame retardant, metakaolin, and optional additives.

[0086] The flame retardant polymer composition described herein can be made, for example, by compounding a polymer containing a flame retardant, metakaolin, and optional additives, such as reinforcing materials. Compounding itself is a technique well known to those skilled in the art of polymer processing and manufacturing, and consists of preparing a plastic compound by mixing and / or blending a polymer and optional additives in a molten state. In the art, compounding is understood to be different from a blending or mixing process that is carried out at a temperature below the melting of the components. Compounding can be used, for example, to form a masterbatch composition. Compounding can involve, for example, adding a masterbatch composition to a polymer to form a further polymer composition.

[0087] The flame retardant polymer composition described herein may be extruded, for example. Compounding may be performed, for example, using a screw compounder, such as a twin screw compounder, for example, a Baker Perkins 25 mm twin screw compounder. Compounding may be performed, for example, using a multi-roll mill, for example, a two-roll mill. Compounding may be performed, for example, using a co-kneader or an internal mixer. The method disclosed herein may include, for example, compression molding or injection molding. The polymer and / or the flame retardant and / or the high aspect ratio particulate mineral and / or other additives (e.g., reinforcing materials) may be premixed and fed from a single hopper or fed from different hoppers to different zones of the extruder.

[0088] The resulting melt may be, for example, cooled, for example in a water bath, and then pelletized. The resulting melt may be calendered to form a sheet or film.

[0089] The flame retardant polymer compositions described herein may, for example, be molded into a desired shape or article. Molding the flame retardant polymer compositions may involve, for example, heating the composition to soften it. The polymer compositions described herein may, for example, be molded by molding (e.g., compression molding, injection molding, stretch blow molding, injection blow molding, overmolding), extrusion, casting, or thermoforming.

[0090] The foregoing describes broadly, but without limitation, certain aspects and / or embodiments of the present invention. Variations and modifications that are readily apparent to one of ordinary skill in the art are intended to be within the scope of the invention, as defined in or by the accompanying claims. EXAMPLES

[0091] Example 1 Various formulations shown in Tables 1, 2, 3 and 4 were prepared and tested for physical properties. The results are shown in Figures 1-8. In the example using metakaolin, the metakaolin had a shape factor of 8.7 and a soluble alumina content of 22.2%. For the data in Figure 7, NR indicates sample results that did not meet the V2 standard; furthermore, the lack of results in Figure 7 means that testing at such thicknesses was not performed (e.g., thicker samples of the same formulation failed to meet the V0 standard). [Table 1] [Table 2] [Table 3] [Table 4]

[0092] Example 2 Corrosion Testing: Various formulations shown in Table 5 were prepared and tested for corrosion potential. The results are shown in Figure 9. In the example using metakaolin, the metakaolin had a shape factor of 8.7 and a soluble alumina content of 22.2%.

[0093] A known difficulty with phosphinate-based flame retardant additives, such as Clariant's Exolit product line (including Exolit OP 1314 used in this study), is that they tend to increase the corrosion potential of plastic compounds (including the glass-fiber-filled polyamide 66 compound used in this study) to processing equipment, including extruder screws, barrels, and other metal parts that come into contact with the molten resin. Exolit OP 1314 is a non-halogenated flame retardant based on an organic phosphinate.

[0094] To evaluate and compare the corrosion potential of the different formulations used in this study, an internal test method was developed that simulates the high shear processing conditions these formulations experience inside plastic compounding extruders and injection molding machines, although any such method or equipment that includes removable metal inserts may be used.

[0095] Testing uses a standard laboratory size injection molding machine (e.g., the Arburg Allrounder 370E 600-170 used in this study) with a mold specifically designed to allow a removable metal insert to be mounted in the mold cavity on the fixed side of the injection molding press. The mold setup allows the injection molding shots to be made directly on the removable metal insert. The insert will come into contact with the injection molding shots many times (a minimum of approximately 100 shots is required) before being removed for corrosion testing. Due to the limited number of shots made on the metal insert, corrosion testing is often qualitative, but with a larger number of shots for more corrosive materials it is possible to make it quantitative. Quantitative analysis will be done using the weight loss of the metal insert (after appropriate corrosion cleaning).

[0096] To compare the corrosion potential of the different formulations used in this study, the injection molding conditions (operating parameters) used were kept constant for all the formulations. Table 5 shows the three different formulations used to evaluate the effect of metakaolin and hydrotalcite on the corrosivity of these formulations.

[0097] The "control" formulation 7 contains only Exolit Op1314, PA66 resin and glass fiber. The other two formulations 8 and 9 contain either hydrotalcite or metakaolin as a corrosion inhibitor. Hydrotalcite is generally used in this type of application as an acid scavenger at about 0.75 wt% loading, which is the loading used in formulation 8. Metakaolin was used at a higher loading (7.5 wt%) (in formulation 9) because it is desirable / necessary in these formulations to function as a flame retardant synergist.

[0098] A visual comparison of the results in Figure 9 shows that the control formulation 7, which does not contain a corrosion inhibitor, has the deepest corrosion effect as evidenced by the darker color at the top of the insert that is first exposed to the molten plastic compound. The insert used with formulation 8, which contains hydrotalcite, also shows significant corrosion, but the effect is spread over a larger area. It does not show the deep / dark spots evident in the control sample. The best performance appears to be formulation 9, which contains metakaolin, as both the spread of the corroded area and the depth / darkness of the corroded spots appear to be less pronounced.

[0099] Table 5: Formulations used for comparative comparison of the corrosion potential of Exolit-based flame retardants PA66 [Table 5]

[0100] FIG. 9 shows a clear reduction in the visual appearance of the corroded inserts in injection molding tests indicating the effectiveness of metakaolin in reducing the corrosion potential of PA66 formulations containing phosphinate flame retardants such as Exolit OP 1314.

[0101] The present invention and / or disclosed aspects are further illustrated by reference to the following non-limiting numbered paragraphs that describe exemplary embodiments.

[0102] 1. A flame retardant polymer composition comprising a polymer, a flame retardant, and metakaolin; wherein when the flame retardant polymer is formed into a layer having a thickness of about 1 / 8 inch or less and about 1 / 128 inch or more, the composition has a flame retardant rating of V0 as determined by United Laboratories Standard Test 94, 6th Edition.

[0103] 2. A flame-retardant polymer composition of paragraph 1, wherein when the flame-retardant polymer is formed into a layer having a thickness of about 1 / 16 inch or less and about 1 / 64 inch or more, the flame-retardant rating of the composition is V0 as determined by United Laboratories Standard Test 94, 6th Edition.

[0104] 3. A flame-retardant polymer composition of paragraph 1, wherein when the flame-retardant polymer is formed into a layer having a thickness of about 1 / 32 inch or less and about 1 / 64 inch or more, the flame-retardant rating of the composition is V0 as determined by United Laboratories Standard Test 94, 6th Edition.

[0105] 4. The flame retardant polymer composition of any of paragraphs 1-3, wherein the metakaolin has a shape factor of less than 20, optionally 10 or less, or 8 or less, or 5 or less.

[0106] 5. The flame retardant polymer composition of any of paragraphs 1-4, wherein the metakaolin has a soluble alumina content of about 10 wt% to about 30 wt% by weight of the metakaolin, optionally about 14 wt% to about 28 wt%, or about 18 wt% to about 26 wt%, or about 20 wt% to about 26 wt% by weight of the metakaolin. Optionally, the metakaolin has a soluble alumina content of at least about 10 wt%, or at least about 12 wt%, or at least about 14 wt%, or at least about 18 wt%, or at least about 20 wt%, based on the total weight of the metakaolin, and / or the soluble alumina content will be up to 30 wt%, or up to 28 wt%, or up to 26 wt%, or up to 24 wt%, by weight based on the total weight of the metakaolin.

[0107] 6. The flame retardant polymer composition of any of paragraphs 1-5, wherein the polymer is selected from a polyalkylene (e.g., polyethylene, polypropylene, or polybutylene), a polyvinyl ester (of the general formula -[RCOOCHCH2]-), a polystyrene, a polyvinyl chloride, a polyvinyl acetate, a polyvinyl alcohol, a polyacrylonitrile, an acrylonitrile butadiene styrene, a polyamide, a polylactic acid, a polybutylene terephthalate, a polyethylene terephthalate, a polycarbonate, a polyvinyl acetate (e.g., ethylene vinyl acetate or poly(meth methacrylate)), a copolymer of two of the enumerated polymers, a terpolymer of three of the enumerated polymers, or a combination of two or more thereof. Optionally, the polymer is a polyamide.

[0108] 7. The flame retardant polymer composition of any of paragraphs 1 to 6, wherein the flame retardant is an intumescent flame retardant.

[0109] 8. The flame retardant polymer composition of any of paragraphs 1-7, wherein the flame retardant is a phosphorus and / or nitrogen containing compound; for example, red phosphorus, a phosphate, a polyphosphate (e.g., melamine polyphosphate), a phosphonate (e.g., dimethyl methylphosphonate (DMMP)), a phosphinate (e.g., aluminum diethylphosphinate), a halogenated organic phosphate (e.g., tris(1,3-dichloro-2-propyl)phosphate, tetrakis(2-chloroethyl)dichloroisoentyl diphosphate), a phosphazene, a polyphosphazene, a triazine (e.g., melamine cyanurate), an organic phosphate (e.g., triphenyl phosphate (TPP), resorcinol bis(diphenyl phosphate) (RDP), bisphenol A diphenyl phosphate (BADP), tricresyl phosphate (TCP)), or one or more combinations thereof. Optionally, the flame retardant is an organic phosphate, an organic phosphinate, a halogenated organic phosphate, or one or more combinations thereof. Optionally, the flame retardant is an organic phosphinate.

[0110] 9. The flame retardant polymer composition of any of paragraphs 1 through 8, wherein the flame retardant is present in an amount of greater than about 10 or 12 or 13 or 14 or 15 wt% and less than or equal to 20 or 18 or 17.5 or 16.5 or 16 wt%, based on the total weight of the flame retardant polymer composition.

[0111] 10. The flame retardant polymer composition of any of paragraphs 1 through 9, wherein the metakaolin is present in an amount of at least about 1 wt%, or 3 wt%, or 5 wt%, or 7 wt%, and less than 40 wt%, or not more than 20 wt%, or 15 wt%, or 12 wt%, or 10 wt%, or 8 wt%, based on the total weight of the flame retardant polymer composition.

[0112] 11. The flame retardant polymer composition of any of paragraphs 1 through 10, when formed into a layer having a thickness of about 1 / 32 inch or less and about 1 / 64 inch or more, having a total flame time of the composition, as determined by United Laboratories Standard Test 94, 6th Edition, of less than 50 seconds, or optionally less than 40 seconds, or optionally less than 30 seconds, or for a thickness of about 1 / 64 inch, less than 50 seconds or optionally less than 40 seconds.

[0113] 12. The flame retardant polymer composition of any of paragraphs 1-11, wherein the composition has an average molecular weight that is at least 3%, or optionally at least 5%, or at least about 10%, or at least about 15%, or at least about 20%, or at least about 30%, or at least about 40% greater than the average molecular weight of an otherwise identical flame retardant polymer composition, except that the composition contains the same amount of a mineral additive different from metakaolin and / or a strengthening additive different from metakaolin, such as hydrotalcite, wollastonite, mica, talc, hydrous kaolin, or calcined kaolin.

[0114] 13. The flame retardant polymer composition of any of paragraphs 1-12, wherein the composition has an intrinsic viscosity that is at least 3 ml / g, or optionally at least 4 ml / g or at least about 5 ml / g or at least about 7 ml / g greater than the intrinsic viscosity number of an identical flame retardant polymer composition except that the composition contains the same amount of a mineral additive different from metakaolin and / or a mineral additive different from metakaolin, such as hydrotalcite, wollastonite, mica, talc, hydrous kaolin, or calcined kaolin.

[0115] 14. The flame retardant polymer composition of any of paragraphs 1 through 13, wherein the flame retardant polymer composition has improved corrosion resistance when compared to an identical flame retardant polymer composition except that the flame retardant polymer composition contains the same amount of a mineral additive other than metakaolin and / or a mineral additive other than metakaolin, such as hydrotalcite, wollastonite, mica, talc, hydrous kaolin, or calcined kaolin.

[0116] 15. The flame retardant polymer composition of any of paragraphs 1-14, further comprising a reinforcing additive present in an amount of about 10 wt% to about 40 wt%. The reinforcing additive may be, for example, wollastonite, talc, mica, hydrous kaolin, calcined kaolin, magnesium oxysulfate, and / or reinforcing fibers. The reinforcing fibers may be, for example, glass fibers, carbon fibers, aramid fibers (e.g., Kelvar®, Nomex®, Technora®), wood fibers, basalt fibers, or combinations of one or more thereof.

[0117] 16. The flame retardant polymer composition of paragraph 15, wherein the combined amount of metakaolin and reinforcing additive in the composition is up to 20 wt%, or 30 wt%, or 40 wt%, or 50 wt%, based on the total weight of the composition.

[0118] 17. The flame retardant polymer composition of paragraph 15 or paragraph 16, wherein the reinforcing additive is selected from glass fibers, wollastonite, talc, mica, magnesium oxysulfate, carbon fibers, hydrous kaolin having a shape factor greater than 20 (or preferably greater than or equal to 60), calcined kaolin, and combinations thereof.

[0119] 18. An article comprising a substrate material of any of paragraphs 1 to 17 and a flame retardant polymer composition.

[0120] 19. The article of paragraph 18, wherein the substrate material is an electrical cable, or an electrical or electronic component, or an automotive component, and the substrate material is made of or coated with the flame retardant polymer composition.

Claims

1. a polymer; a flame retardant; metakaolin A flame-retardant polymer composition comprising: when the flame-retardant polymer is formed in a layer having a thickness of about 1 / 8 inch or less and about 1 / 128 inch or more, the flame-retardant rating of the composition is V0 as determined by United Lab oratories Standard Test 94, 6th Edition, flame-retardant polymer.

2. When the flame-retardant polymer is formed in a layer having a thickness of about 1 / 16 inch or less and about 1 / 64 inch or more, the flame-retardant rating of the composition is V0 as determined by United Laboratories Standard Test 94, 6 th Edition, the flame-retardant polymer composition according to claim 1.

3. When the flame-retardant polymer is formed in a layer having a thickness of about 1 / 32 inch or less and about 1 / 64 inch or more, the flame-retardant rating of the composition is V0 as determined by United Laboratories Standard Test 94, 6 th Edition, the flame-retardant polymer composition according to claim 1.

4. The metakaolin has a shape factor of less than 20, optionally 10 or less, or 8 or less, or 5 or less, the flame-retardant polymer composition according to any one of claims 1 to 3 above.

5. The metakaolin has a soluble alumina content of about 10 wt% to about 30 wt% of the weight of the metakaolin, optionally about 14 to about 28 wt% of the weight of the metakaolin, or about 18% to about 26%, or about 20% to about 26% of the weight of the metakaolin, the flame-retardant polymer composition according to any one of claims 1 to 3 above.

6. 。 The polymer is a polyamide, the flame-retardant polymer composition according to any one of claims 1 to 3 above.

7. The flame retardant is an intumescent flame retardant, the flame-retardant polymer composition according to any one of claims 1 to 3 above.

8. The flame retardant is an organic phosphinate, the flame-retardant polymer composition according to any one of claims 1 to 3 above.

9. The flame retardant is present in an amount greater than about 10 or 12 or 13 or 14 or 15 wt% and less than or equal to 20 or 18 or 17.5 or 16.5 or 16 wt% based on the total weight of the flame-retardant polymer composition, the flame-retardant polymer composition according to any one of claims 1 to 3 above.

10.

10.

10.

10.

10.

10. The metakaolin is at least about 1 or 3 or 5 or 7 wt% and is present in an amount of 20 or 15 or 12 or 10 or 8 wt% or less based on the total weight of the flame-retardant polymer composition according to any one of claims 1 to 3.

11. The flame-retardant polymer composition has improved corrosion resistance when compared with a flame-retardant polymer composition that is identical except that it contains a mineral additive different from metakaolin in the same amount. The flame-retardant polymer composition according to any one of claims 1 to 3.

12. The flame-retardant polymer composition according to any one of claims 1 to 3, further comprising a reinforcing additive present in an amount of about 10 wt% to about 40 wt%.

13. The total amount of metakaolin and the reinforcing additive in the composition is at most 20 wt%, or 30 wt%, or 40 wt% or 50 wt% based on the total weight of the composition according to claim 12.

14. The flame-retardant polymer composition according to claim 12, wherein the reinforcing additive is selected from glass fiber, wollastonite, talc, mica, magnesium oxysulfate, carbon fiber, hydrated kaolin having a shape factor greater than 20 (or preferably 60 or more), calcined kaolin, and combinations thereof.

15. An article comprising a substrate material and the flame-retardant polymer composition according to any one of claims 1 to 3.

16. The substrate material is an electrical cable, an electrical or electronic component, or an automotive component, and the substrate material is made of the flame-retardant polymer composition or coated with the flame-retardant polymer composition. The article of claim 15. ​ ​ ​ ​ ​ ​ ​

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