Polyamide compositions with mineral additives

Abstract

The present disclosure provides a flame retardant polyamide composition comprising a polyamide, a flame retardant package, and a reinforcing agent. The flame retardant package includes from 5 wt.% to 30 wt.% of a first mineral flame retardant, based on the total weight of the flame retardant polyamide composition, and from 5 wt.% to 30 wt.% of a second mineral flame retardant, based on the total weight of the flame retardant polyamide composition. The flame retardant package comprises less than 5 wt.% halogens, less than 5 wt.% phosphorous, and less than 5 wt.% nitrogen; the total mineral content of the flame retardant polyamide composition is greater than 30 wt.%.

Description

POLYAMIDE COMPOSITIONS WITH MINERAL ADDITIVESTECHNICAL FIELD

[0001] The present disclosure relates to flame retardant polyamide compositions in which the flame retardant package contains very low amounts of or no non-mineral components, such as carbon, a halogen, phosphorous, and / or nitrogen.BACKGROUND

[0002] Conventional flame retardant polyamide compositions often rely upon toxic and / or environmentally damaging components, such as halogen-containing compounds and phosphorous-containing compounds, to provide flame retardancy. Further, conventional compositions tend to have a large carbon footprint due to the inclusion of fossil / fossil fuel-based components in their flame retardant packages. While attempts have been made to use more environmentally-friendly flame retardants, such formulations suffer from decreased mechanical properties, such as reduced impact strength and ductility.

[0003] U.S. Patent No. 7,294,661 B2 describes certain flame resistant aromatic polyamide resin molding compositions employing a non-halogenated flame retardant. More particularly, the document describes such aromatic polyamide resin molding compositions containing selected phosphinates as flame retardants.

[0004] WO2021128964A1 describes an electroplated nylon material and a preparation method thereof. Components of the electroplated nylon material contain, by weight, 50-80 parts polyamide, 20-50 parts modified minerals, and 2-8 parts compatibilizer. The modified minerals are obtained after minerals have gone through coupling agent processing and rare earth ion processing.

[0005] EP3183293B1 describes a housing element for electrical equipment including a flame-retardant composite composition containing a combination of at least one polymer belonging to the polyamide category, at least two specific types of filler, and at least one flame-retardant agent. Specifically, this composition provides favorable mechanical and flame retardant properties. The composition also presents low humidity recovery, strong resistance to arc tracking, high fire resistance, an absence of corrosiveness towards the tools with which the composition is brought into contact during its shaping, and harmlessness with respect to the environment and the health of people intended to be in contact with the constituent composition of the housing element.

[0006] Even in view of these documents, the need exists for environmentally friendly polyamide compositions capable of achieving both flame retardancy and mechanical performance, while limitingcontent of non-mineral components, such as components containing carbon, halogens, phosphorous, and nitrogen.SUMMARY

[0007] Embodiments described herein relate to a flame retardant polyamide composition containing (for example, from 5 weight percent (wt.%) to 85 wt.%) of a polyamide, such as PA-6, PA-66, PA-6 / PA-66 copolymers, PA-6,6 / 61, PA-6I / 6T, PA-6,6 / 6T, PA- 12, PA-610, or PA-612, or combinations thereof. In some embodiments, the polyamide includes PA-6, PA-66, or a PA-6 / 66 copolymer. In some embodiments, the polyamide includes PA-6 in an amount ranging from 10 wt.% to 50 wt.% of the total flame retardant polyamide composition and / or PA-66 in an amount ranging from 10 wt.% to 50 wt.% of the total flame retardant polyamide composition. The flame retardant polyamide composition further includes a flame retardant package containing from 5 wt.% to 30 wt.% of a first mineral flame retardant (for example, magnesium hydroxide) based on the total weight of the flame retardant polyamide composition. The first mineral flame retardant may be an amino silane treated mineral flame retardant (for example, amino silane treated magnesium hydroxide). The flame retardant polyamide composition further includes from 5 wt.% to 30 wt.% of a second mineral flame retardant (for example, aluminum oxide hydroxide (boehmite)) based on the total weight of the flame retardant polyamide composition. The second mineral flame retardant may be an amino silane treated mineral flame retardant (for example, amino silane treated boehmite). The flame retardant package may contain less than 5 wt.% (for example, less than 2 wt.%, less than 0.1 wt.%) halogens, less than 5 wt.% (for example, less than 2 wt.%, less than 0.1 wt.%) phosphorous, and / or less than 5 wt.% (for example, less than 2 wt.%, less than 0.1 wt.%) nitrogen. In some embodiments, the flame retardant package contains less than 5 wt.% carbon. The flame retardant polyamide composition further contains a reinforcing agent, for example, glass fibers, wollastonite, talc, mica, clay, or combinations thereof. The reinforcing agent may be an amino silane treated reinforcing agent (for example, amino silane treated wollastonite). In some embodiments, the reinforcing agent is needle-shaped. In some embodiments, the total mineral content of the flame retardant polyamide composition (for example, from the flame retardant package and the reinforcing agent) is greater than 30 wt.%. In some embodiments, the flame retardant polyamide composition further contains additives, such as stabilizers, colorants, lubricants, antioxidants, or light stabilizers, or combinations thereof.

[0008] In certain embodiments, the flame retardant polyamide composition demonstrates an ultimate tensile strength greater than 1.8%, as measured by ISO Test No. 527:2012, and an impact resistance of greater than 30 kilojoules per square meter (kJ / m2), as measured using Charpy unnotched resistancedescribed in TSO 179-1 (2010). In some embodiments, the flame retardant polyamide composition demonstrates a passing value for a glow wire flammability index test, as measured by TEC 60695-2-12 at a temperature of at least 850 °C and at a width of 1.6 mm. In some embodiments, the flame retardant polyamide composition demonstrates a passing value of at least V2 (rating) for UL94 performance at a width of 1.6 mm and 3.2 mm.

[0009] Embodiments described herein include a flame retardant polyamide composition containing a polyamide; a flame retardant package that includes from 5 wt.% to 30 wt.% of a first mineral flame retardant, based on the total weight of the flame retardant polyamide composition, and from 5 wt.% to 30 wt.% of a second mineral flame retardant, based on the total weight of the flame retardant polyamide composition; and a mineral reinforcing agent. The flame retardant package contains less than 5 wt.% halogens, less than 5 wt.% phosphorous, and less than 5 wt.% nitrogen. The total mineral content of the flame retardant polyamide composition is greater than 30 wt.%. In certain embodiments, the flame retardant polyamide composition has a tensile strength at break greater than 1.8%, as measured by ISO Test No. 527:2012, and an impact resistance greater than 30 kJ / m2, as measured using Charpy unnotched resistance described in ISO 179-1 (2010).

[0010] In some embodiments, the flame retardant package contains less than 0.1 wt.% halogens, less than 0.1 wt.% phosphorous, and / or less than 0.1 wt.% nitrogen. In some embodiments, the flame retardant package contains less than 5 wt.% carbon. In some embodiments, the first mineral flame retardant includes magnesium hydroxide. In some embodiments, the magnesium hydroxide is an amino silane treated magnesium hydroxide. In some embodiments, the second mineral flame retardant includes boehmite. In some embodiments, the reinforcing agent includes glass fibers, wollastonite, talc, mica, or clay, or any combination thereof. In some embodiments, the reinforcing agent is an amino silane treated reinforcing agent. In some embodiments, the flame retardant polyamide composition contains from 5 wt.% to 85 wt.% polyamide, based on the total weight of the flame retardant polyamide composition. In some embodiments, the polyamide includes PA-6. PA-66, PA-6 / PA-66 copolymers, PA-6.6 / 61, PA-6I / 6T, PA-6.6 / 6T, PA-12, PA-610, or PA-612, or any combination thereof. In some embodiments, the polyamide includes polyamide 6 (PA-6), or polyamide 6,6 (PA-66), or any combination thereof. In some embodiments, the polyamide includes PA-6 in an amount ranging from 10 wt.% to 50 wt.% of the total flame retardant polyamide composition. In some embodiments, the polyamide includes PA-66 in an amount ranging from 10 wt.% to 50 wt.% of the total flame retardant polyamide composition. In some embodiments, the reinforcing agent includes needle-shaped reinforcing agents. In some embodiments, the flame retardant polyamidecomposition demonstrates a passing value for a glow wire flammability test, as measured by IEC 60695-2-12 at a temperature of at least 850 °C and at a width of 1.6 mm. In some embodiments, the flame retardant polyamide composition demonstrates a passing value of at least V2 (rating) for UL94 performance at a width of 1.6 mm and 3.2 mm. In some embodiments, the flame retardant polyamide contains an additive, in which the additive includes stabilizers, colorants, lubricants, antioxidants, or light stabilizers, or any combination thereof.

[0011] Embodiments described herein include a flame retardant polyamide composition consisting of a polyamide; a flame retardant package including from 5 wt.% to 30 wt.% of a treated magnesium hydroxide, based on the total weight of the flame retardant polyamide composition, and from 5 wt.% to 30 wt.% boehmite, based on the total weight of the flame retardant polyamide composition; and a wollastonite reinforcing agent. In certain embodiments, the flame retardant polyamide composition has a tensile strength at break greater than 1.8%, as measured by ISO Test No. 527:2012, and an impact resistance of greater than 30 kJ / m2, as measured using Charpy unnotched resistance described in ISO 179-1 (2010).

[0012] Embodiments described herein include a flame retardant polyamide composition containing a polyamide; a flame retardant package including from 5 wt.% to 30 wt.% of an amino silane treated magnesium hydroxide, based on the total weight of the flame retardant polyamide composition, and from 5 wt.% to 30 wt.% boehmite, based on the total weight of the flame retardant polyamide composition; and a wollastonite reinforcing agent. The flame retardant package contains less than 2 wt.% halogens, less than 2 wt.% phosphorous, less than 2 wt.% nitrogen, and less than 2 wt.% carbon. The total mineral content of the flame retardant polyamide composition is greater than 30 wt.%. In certain embodiments, the flame retardant polyamide composition has a tensile strength at break greater than 1.8%, as measured by ISO Test No. 527:2012, and an impact resistance of greater than 30 kJ / m2, as measured using Charpy unnotched resistance described in ISO 179-1 (2010). In some embodiments, the boehmite of the flame retardant package, the wollastonite reinforcing agent, or both, are amino silane treated materials.

[0013] Aspects and advantages of these exemplary embodiments and other embodiments, are discussed in detail herein. Moreover, both the foregoing information and the following detailed description provide merely illustrative examples of various aspects and embodiments, and are intended to provide an overview or framework for understanding the nature and character of the claimed aspects and embodiments. Accordingly, these and other objects, along with advantages and features of the present disclosure, will become apparent through reference to the following description and the accompanying drawings.Furthermore, the features of the various embodiments described herein are not mutually exclusive and may exist in various combinations and permutations.DETAILED DESCRIPTION

[0014] The present disclosure describes various embodiments related to flame retardant polyamide compositions. The description may use the phrases “in certain embodiments,” “in various embodiments,” “in an embodiment,” or “in embodiments,” which may each refer to one or more of the same or different embodiments. Furthermore, the terms “comprising,” “including,” “having,” and the like, as used with respect to embodiments of the present disclosure, are synonymous. The term “plurality” as used herein refers to two or more items or components. The terms “about” or “approximately” are defined as being close to as understood by one of ordinary skill in the art. In one non-limiting embodiment, these terms are defined to be within 10%, preferably within 5%, more preferably within 1%, and most preferably within 0.5%.

[0015] As noted above, many conventional polyamide compositions use environmentally-unfriendly chemicals (for example, halogen-containing, phosphorous-containing, nitrogen-containing, and / or carbon-containing chemicals) to provide flame retardancy. In addition, conventional compositions have been found to have a large carbon footprint due to the inclusion of carbon-based components in their flame retardant packages.

[0016] Applicant recognized that polyamide compositions that employ the disclosed mineral-based formulations / additives are surprisingly able to demonstrate a synergistic combination of performance features, such as mechanical performance (for example, tensile strength and impact resistance) along with flame retardant performance, while also being environmentally friendly. Mineral flame retardants, as disclosed herein, may be considered more environmentally friendly / sustainable in comparison to conventional flame retardants, which rely on components that may be toxic or damaging to the environment, such as compounds containing halogens, carbon, and phosphorous, among others. However, the addition of mineral flame retardants has been known to negatively impact the properties of polymers / polymer compositions, particularly polyamides. Specifically, it is conventionally believed mechanical properties, such as impact strength and ductility, may be negatively affected by mineral flame retardants. Further, high loadings of mineral flame retardants may be required for flame retardant performance. This high loading may lead to difficulties in processing due to increased viscosity and poor flow properties.

[0017] Unlike conventional flame retardant packages (and the resulting polymer compositions), the flame retardant packages disclosed herein contain inorganic minerals. These inorganic minerals contain low amounts or are substantially free of halogens, phosphorous, nitrogen, and / or carbon. Advantageously, the disclosed mineral flame retardants have been found to provide performance advantages, particularly in certain applications, such as circuit breakers and / or other electrical applications, in which excellent electrical insulation and arc quenching are needed.

[0018] Applicant determined that the use of the disclosed mineral components and reinforcing agents increases flame retardancy without loss of mechanical properties. Without wishing to be bound by theory, it is postulated that boehmite contributes to ceramization (as well as water release and an endothermic decomposition mechanism), while magnesium hydroxide contributes to increased water release. Thus, mechanical and flame retardant properties are surprisingly both improved in the disclosed compositions, contrary to conventional wisdom in the art.

[0019] Further, in some cases, due to the disclosed flame retardant packages and filler materials, the flame retardant compositions provide for a notably smaller carbon footprint, as compared to conventional compositions that employ more carbon-containing components. The flame retardant compositions disclosed herein do not demonstrate the deficiencies in mechanical properties noted in known polyamide compositions that include mineral flame retardants and / or a high total mineral content.

[0020] Polyamide Composition

[0021] The embodiments described herein relate to flame retardant polyamide compositions including a polyamide, a flame retardant package, and a reinforcing agent. In some embodiments, the flame retardant package is a mineral flame retardant package containing a first mineral flame retardant and a second mineral flame retardant. In some embodiments, the first mineral flame retardant is magnesium hydroxide. In some embodiments, the second mineral flame retardant is aluminum oxide hydroxide (boehmite). In some embodiments, the reinforcing agent is a mineral reinforcing agent. In some embodiments, the reinforcing agent is wollastonite.

[0022] In some embodiments, the first mineral flame retardant and / or the second mineral flame retardant may be treated with an amino silane to provide a surface treated (for example, an aminopoly siloxane coated) mineral flame retardant. In some embodiments, the reinforcing agent may be treated with an amino silane to provide a surface treated (for example, an aminopolysiloxane coated) reinforcing agent. The aminopolysiloxane coating is substantially free of other additives, such as rare earth elements. Specifically, the aminopolysiloxane coating contains less than 1 wt.% rare earth elements. For example,the aminopolysiloxane coating contains less than 0.5 wt.%, or less than 0.1 wt.%, or less than 500 ppm, or less than 250 ppm, or less than 100 ppm rare earth elements.

[0023] Importantly, in some cases, the flame retardant package contains very low amounts, if any, of halogens, phosphorous, nitrogen, and / or carbon. The low amounts, if any, of these components contribute to the aforementioned environmental advantages and other performance features described herein. In addition to being more environmentally friendly, the disclosed flame retardant polyamide compositions demonstrate excellent flame retardant capability, as well as superior mechanical properties, as compared to conventional compositions that employ higher amounts of the conventional, non-environmentally friendly flame retardant and / or reinforcing agent components.

[0024] In some cases, the flame retardant polyamide composition may have a high mineral content, for example, greater than 30 wt.%. Conventionally, mineral content has been relegated to lower amounts for performance reasons, including those discussed herein. However, Applicant recognized that, with the specific mineral components disclosed herein, a high overall mineral content contributes to the aforementioned synergistic combination of performance features.

[0025] In some cases, total mineral content (i.e., the combined amount of mineral flame retardants, mineral reinforcing agents, and optionally mineral additives) of the flame retardant polyamide composition may range from 30 wt.% to 95 wt.% of the total polyamide composition. For example, the total mineral content of the flame retardant polyamide composition may range from 35 wt.% to 90 wt.%, from 40 wt.% to 85 wt.%, from 45 wt.% to 80 wt.%, from 50 wt.% to 75 wt.%, from 55 wt.% to 70 wt.%, or from 60 wt.% to 65 wt.% of the total polyamide composition. In terms of upper limits, the total mineral content of the flame retardant polyamide composition may be less than 95 wt.%. For example, the total mineral content of the flame retardant polyamide composition may be less than 90 wt.%. less than 85 wt.%, less than 80 wt.%, less than 75 wt.%, less than 70 wt.%, or less than 65 wt.%. In terms of lower limits, the total mineral content of the flame retardant polyamide composition may be greater than 35 wt.%. greater than 40 wt.%. greater than 45 wt.%. greater than 50 wt.%. or greater than 55 wt.%. In some embodiments, the aforementioned ranges correspond to the combined weight contribution of the mineral flame retardants and the mineral reinforcing agents within the total polyamide composition.

[0026] Flame Retardant Package

[0027] The flame retardant package contains first and second mineral flame retardants. As used herein, the term “mineral” refers to an inorganic compound that lacks carbon, other than a small amount of carbon that may be present in an aminopolysiloxane coating of certain amino silane treated inorganic compoundsdescribed herein. Example inorganic compounds include, but are not limited to, metal or metalloid compounds, including oxides, hydroxides, carbonates, silicates, and sulfates. Importantly, the flame retardant package does not contain or contains only small amounts of the non-mineral components discussed herein.

[0028] It has surprisingly been found a mineral flame retardant package containing a combination of magnesium-based flame retardants and aluminum-based flame retardants (for example, a first mineral flame retardant and a second mineral flame retardant) is not only compatible with polyamides, but provides increases in performance. Specifically, it has been found that the mineral flame retardant packages disclosed herein demonstrate flame retardant efficiency, without the unfavorable environmental and health impacts of conventional flame retardants.

[0029] The flame retardant package may contain the first mineral flame retardant and the second mineral flame retardant in a ratio ranging from 1:6 to 6:1, e.g., from 1:5.5 to 5.5:1, from 1:5 to 5:1, from 1:4.5 to 4.5:1, from 1:4 to 4:1, from 1:3.5 to 3.5:1, from 1:3 to 3:1, from 1:2.5 to 2.5:1, from 1:2 to 2:1, or from 1:1.5 to 1.5:1. In terms of upper limits, the ratio of the first mineral flame retardant to the second mineral flame retardant in the flame retardant package may be less than 6:1, e.g., less than 5.5:1, less than 4.5:1, less than 4:1, less than 3.5:1, less than 3:1, less than 2.5:1, less than 2:1, less than 1.5:1, or 1:1. In terms of lower limits, the ratio of the first mineral flame retardant to the second mineral flame retardant in the flame retardant package may be greater than 1:6, e.g., greater than 1:5.5, greater than 1:5, greater than 1:4.5, greater than 1:4, greater than 1:3.5, greater than 1:3, greater than 1:2.5, greater than 1:2, or greater than 1:1.5.

[0030] The flame retardant package may contain the first mineral flame retardant in an amount ranging from 5 wt.% to 30 wt.% of the total flame retardant polyamide composition, e.g., from 6 wt.% to 29 wt.%, from 7 wt.% to 28 wt.%, from 8 wt.% to 27 wt.%, from 9 wt.% to 26 wt.%, from 10 wt.% to 25 wt.%, from 11 wt.% to 24 wt.%, from 12 wt.% to 23 wt.%, from 13 wt.% to 22 wt.%, from 14 wt.% to 21 wt.%, from 15 wt.% to 20 wt.%, from 16 wt.% to 19 wt.%, or from 17 wt.% to 18 wt.%. In terms of upper limits, the flame retardant package may contain the first mineral flame retardant in an amount less than 30 wt.% of the total flame retardant polyamide composition, e.g., less than 29 wt.%, less than 28 wt.%, less than 27 wt.%, less than 26 wt.%, less than 25 wt.%, 24 wt.%, less than 23 wt.%, less than 22 wt.%, less than 21 wt.%, less than 20 wt.%, less than 19 wt.%, or less than 18 wt.%. In terms of lower limits, the flame retardant package may contain the first mineral flame retardant in an amount greater than 5 wt.% of the total flame retardant polyamide composition, e.g., greater than 6 wt.%, greater than 7 wt.%, greater than8 wt.%, greater than 9 wt.%, greater than 10 wt.%, greater than 11 wt.%, greater than 12 wt.%, greater than 13 wt.%, greater than 14 wt.%, greater than 15 wt.%, greater than 16 wt.%, or greater than 17 wt.%.

[0031] Suitable first mineral flame retardants include magnesium compounds. For example, suitable magnesium compounds include magnesium hydroxide (Mg(OH)2, MDH). In some embodiments, the minerals used as the first mineral flame retardant, the second mineral flame retardant, and / or the reinforcing agent are treated with amino silane to alter the surface chemistry of these minerals. For example, in some embodiments, the first mineral flame retardant may include magnesium hydroxide that is treated with an amino silane to provide a surface treated (for example, aminopolysiloxane coated) magnesium hydroxide mineral flame retardant. That is, Applicant recognized that certain of the minerals contemplated herein (for example, magnesium hydroxide, boehmite, wollastonite), in their unmodified or untreated state, expose a large number of polar hydroxyl groups and / or oxide moieties, resulting in a polar or hydrophilic surface that may be less compatible with less polar polymers. This incompatibility may lead to poor dispersion of the mineral(s) in the polymer, which in turn may lead to lessened flame retardancy and / or undesirable effects on mechanical properties. To overcome these challenges, in some embodiments, these minerals may undergo an amino silane surface treatment (for example, to provide an aminopolysiloxane coating) that lessens the polar or hydrophilic character of the mineral, leading to improved dispersion and concomitant improvement in flame retardancy and / or mechanical properties.

[0032] During an amino silane surface treatment, the silicon-functional side of the silane molecule may undergo hydrolysis with the polar surface hydroxyl and / or oxide moieties of the mineral. The hydrolyzed silane molecules may form hydrogen bonds with the polar surface moieties and / or undergo condensation reactions resulting in siloxane oligomers. Condensation reactions with surface hydroxyls or oxides are also possible, leading to grafting of siloxane oligomers to the mineral surface. The organic-functional end of the silane molecule allows the surface treated minerals to interact with the polymer. Non-coupling silanes may improve wetting of the treated inorganic surface with the resin, as well as the quality of dispersion. Coupling silanes may form a chemical bond with the polymer, thereby significantly improving physical properties of the mineral-filled compounds. After amino silane treatment of the minerals described herein, from about 0.2 wt.% to about 2 wt.% (for example, from 0.3 wt.% to 1.5 wt.%) of the treated mineral may contain aminosiloxane monomers, oligomers, and / or polymers coated on or bonded to the mineral surface. These aminosiloxane monomers, oligomers, and / or polymers are collectively referred to herein as aminopolysiloxane or an aminopolysiloxane coating. Minerals that have receivedsuch amino silane treatment may be interchangeably referred to herein as amino silane treated minerals or aminopoly siloxane coated minerals.

[0033] In some embodiments, the first mineral flame retardant may be a commercially-available magnesium hydroxide product. For example, suitable commercial products include magnesium hydroxide products in the MAGNIFIN® MDH product line, available from Huber Advanced Materials, including uncoated standard grades (for example, MAGNIFIN® H-5, MAGNIFIN® H-7, MAGNIFIN® H-10) and aminopolysiloxane coated grades (for example, MAGNIFIN® H-5 IV, MAGNIFIN® H-10 IV). In some embodiments, the first mineral flame retardant is MAGNIFIN® H-5 IV.

[0034] Applicant recognized that that magnesium hydroxide (Mg(OH)2), when used as disclosed herein, particularly in conjunction with polyamide compounds, unexpectedly contributes to overall performance. When heated to temperatures greater than 320 °C, magnesium hydroxide releases water, thereby cooling the material and diluting flammable gases. This reduces the risk of ignition and slows the spread of a fire.

[0035] The flame retardant package may contain the second mineral flame retardant in an amount ranging from 5 wt.% to 30 wt.% of the total flame retardant polyamide composition, e.g., from 6 wt.% to 29 wt.%, from 7 wt.% to 28 wt.%, from 8 wt.% to 27 wt.%, from 9 wt.% to 26 wt.%, from 10 wt.% to 25 wt.%, from 11 wt.% to 24 wt.%, from 12 wt.% to 23 wt.%, from 13 wt.% to 22 wt.%, from 14 wt.% to 21 wt.%, from 15 wt.% to 20 wt.%, from 16 wt.% to 19 wt.%, or from 17 wt.% to 18 wt.%. In terms of upper limits, the flame retardant package may contain the second mineral flame retardant in an amount less than 30 wt.% of the total flame retardant polyamide composition, e.g., less than 29 wt.%, less than 28 wt.%, less than 27 wt.%, less than 26 wt.%, less than 25 wt.%, 24 wt.%, less than 23 wt.%, less than 22 wt.%, less than 21 wt.%, less than 20 wt.%, less than 19 wt.%, or less than 18 wt.%. In terms of lower limits, the flame retardant package may contain the second mineral flame retardant in an amount greater than 5 wt.% of the total flame retardant polyamide composition, e.g., greater than 6 wt.%, greater than 7 wt.%, greater than 8 wt.%, greater than 9 wt.%, greater than 10 wt.%, greater than 11 wt.%, greater than 12 wt.%, greater than 13 wt.%, greater than 14 wt.%, greater than 15 wt.%, greater than 16 wt.%, or greater than 17 wt.%.

[0036] Suitable second mineral flame retardants include compounds that contain aluminum. For example, suitable aluminum compounds include aluminum oxide hydroxide (boehmite). In some embodiments, the boehmite may be treated with an amino silane to provide a surface treated (for example, an aminopolysiloxane coated) boehmite mineral flame retardant, as described above.

[0037] In some embodiments, the second mineral flame retardant may be a commercially-available boehmite product. Examples of suitable commercial products include certain boehmite products in theAPYRAL® or ACTILOX® product lines, available from Nabaltec AG, such as APYRAL® AOH 30, APYRAL® AOH 60, ACTILOX® B30, ACTILOX® B60, ACTILOX® 200SM, ACTILOX® PA 14, ACTILOX® PA-B2, ACTILOX® 200 ASL ACTILOX® B60 AS1, and ACTILOX® AOH Battery. It is noted that certain of these materials, such as ACTILOX® 200 AS1, ACTILOX® B60 AS1, ACTILOX® PA 14, and ACTILOX® PA-B2, contain amino silane treated boehmite.

[0038] Other mineral flame retardants, such as aluminum trihydroxide (Al(OH)s) may release more water than magnesium hydroxide, making it a desirable flame retardant; however, aluminum trihydroxide decomposes at 200 °C, which may make it unsuitable for use in polyamide-based compositions. Certain aluminum-based flame retardants, such as aluminum oxide hydroxide (boehmite) are more thermally stable than aluminum trihydroxide; however, these aluminum-based flame retardants may be less efficient.

[0039] The flame retardant package disclosed herein may be substantially free of halogens or halogencontaining compounds. Specifically, the flame retardant package may contain less than 0.1 wt.% halogens, e.g., less than 500 ppm, less than 250 ppm, less than 100 ppm, less than 50 ppm, or less than 10 ppm halogens. For example, the flame retardant package may have a halogen content that ranges from 0 wt.% to 0.1 wt.%, e.g., from 0 ppm to 500 ppm, from 0 ppm to 250 ppm, from 0 ppm to 100 ppm, from 0 ppm to 50 ppm, or from 0 ppm to 10 ppm.

[0040] The flame retardant package may also be substantially free of phosphorous or phosphorus-containing compounds. Specifically, the flame retardant package may contain less than 0.1 wt.% phosphorous, e.g., less than 500 ppm, less than 250 ppm, less than 100 ppm, less than 50 ppm, or less than 10 ppm phosphorous. For example, the flame retardant package may have a phosphorous content that ranges from 0 wt.% to 0.1 wt.%, e.g., from 0 ppm to 500 ppm, from 0 ppm to 250 ppm, from 0 ppm to 100 ppm, from 0 ppm to 50 ppm, or from 0 ppm to 10 ppm.

[0041] The flame retardant package may be substantially free of nitrogen or nitrogen-containing compounds. Specifically, the flame retardant package may contain less than 0.1 wt.% nitrogen, e.g., less than 500 ppm, less than 250 ppm, less than 100 ppm, less than 50 ppm, or less than 10 ppm nitrogen. For example, the flame retardant package may have a nitrogen content that ranges from 0 wt.% to 0.1 wt.%, e.g., from 0 ppm to 500 ppm, from 0 ppm to 250 ppm, from 0 ppm to 100 ppm, from 0 ppm to 50 ppm, or from 0 ppm to 10 ppm.

[0042] The flame retardant package disclosed herein is substantially free of carbon or carbon-containing compounds. The flame retardant package may contain less than 5 wt.% carbon, e.g., less than 4 wt.%, less than 3 wt.%, less than 2 wt.%, less than 1 wt.%, less than 1000 ppm, less than 500 ppm, 100 ppm, lessthan 50 ppm, or less than 1 ppm carbon. For example, the flame retardant package may have a carbon content that ranges from 0 wt.% to 5 wt.%, e.g., from 0 wt.% to 4 wt.%, from 0 wt.% to 3 wt.%, from 0 wt.% to 2 wt.%, from 0 wt.% to 1 wt.%. from 0 ppm to 1000 ppm, from 0 ppm to 500 ppm, from 0 ppm to 100 ppm, from 0 ppm to 50 ppm, or from 0 ppm to 1 ppm.

[0043] Reinforcing Agent(s)

[0044] The flame retardant polyamide composition disclosed herein further contains a reinforcing agent. The reinforcing agent may include glass fibers, particulate fillers, wollastonite, talc, mica, silicate, quartz, titanium dioxide, wollastonite, kaolin, amorphous silicic acids, magnesium carbonate, magnesium hydroxide, chalk, lime, feldspar, barium sulfate, KEVLAR® fiber, basalt fiber, solid or hollow glass balls or ground glass, permanently magnetic or magnetizable metal compounds or alloys, and also combinations thereof.

[0045] The reinforcing agent may be treated with an amino silane to provide a surface treated (for example, aminopolysiloxane coated) reinforcing agent, as described above. In some cases, the reinforcing agent may be an amino silane treated (for example, aminopolysiloxane coated) acicular wollastonite. In some embodiments, the reinforcing material may be a commercially-available wollastonite product. An example of a suitable commercially-available reinforcing material includes WICROLL® 10PA, available from Nordkalk.

[0046] The reinforcing agent may be in the form of fibers, particles (for example, spheres or powders), flakes, platelets, cylinders, or needles. In some cases, the reinforcing agent is a needle-shaped (acicular) reinforcing agent.

[0047] The flame retardant polyamide composition may contain the reinforcing agent in an amount ranging from 5 wt.% to 30 wt.% of the total flame retardant polyamide composition, e.g., from 10 wt.% to 25 wt.%, or from 15 wt.% to 20 wt.%. In terms of upper limits, the flame retardant polyamide composition may contain the reinforcing agent in an amount less than 30 wt.%, e.g., less than 25 wt.%, or less than 20 wt.%. In terms of lower limits, the flame retardant polyamide composition may contain the reinforcing agent in an amount greater than 5 wt.%, e.g., greater than 10 wt.%, or greater than 15 wt.%.

[0048] Polyamides

[0049] The polyamide polymers of the composition can include aliphatic polyamides, such as polymeric E-caprolactam (PA-6), polyhexamethylene adipamide (referred to herein as PA-6,6, or PA-66), polyhexamethylene sebacamide (referred to herein as PA-6,10 or PA-610), polyhexamethylene dodecanediamde (PA-6,12 or PA-612), or other aliphatic nylons, polyamides with aromatic components,such as paraphenylenediamine and terephthalic acid, and copolymers such as adipate with 2-methyl pentmethylene diamine and 3,5-diacarboxybenzenesulfonic acid or sulfoisophthalic acid in the form of its sodium sultanate salt. The polyamides can include polyaminoundecanoic acid and polymers of bis-paraaminocyclohexyl methane and undecanoic acid. Other polyamides include poly(aminododecanoamide), polyhexamethylene sebacamide, poly(p-xylyleneazeleamide), poly(m-xylylene adipamide), and polyamides from bis(p-aminocyclohexyl)methane and azelaic. sebacic and homologous aliphatic dicarboxylic acids. As used herein, the terms “PA-6 polymer” and “PA-6 polyamide polymer” also include copolymers in which PA-6 is the major component. As used herein the terms “PA-66 polymer” and “PA-66 polyamide polymer” also include copolymers in which PA-66 is the major component. In some embodiments, copolymers such as PA-6,6 / 61; PA-6I / 6T; or PA-6,6 / 6T, or combinations thereof are contemplated for use as the polyamide polymer. In some cases, physical blends, e.g., melt blends, of these polymers are contemplated. In one embodiment, the polyamide polymer contains or consists of PA-6, or PA-6,6, or a combination thereof.

[0050] The polyamide compositions can include polyamides produced through the ring-opening polymerization or polycondensation, including the copolymerization and / or copolycondensation, of lactams. These polyamides can include, for example, those produced from propriolactam, butyrolactam, valerolactam, and caprolactam. For example, in some embodiments, the composition includes a polyamide polymer derived from the polymerization of caprolactam.

[0051] The polyamide compositions can include semi-aromatic polyamides, which are known for high strength, high temperature resistance, as well as adequate resistance to long term heat exposure and dielectric strength. The polyamide compositions can include polyphthalamides, such as PA-6T / 66, PA-6T / 6I. and PA-6T / DT. Polyphthalamides are defined as semi-aromatic polyamides in which the residues of terephthalic acid and / or isophthalic acid account for at least 55 molar percent (mol.%) of the repeat units, as determined in accordance with ASTM D5336. For example, the polyamide may contain polyphthalamides chosen from PA-4T / 4I; PA-4T / 6I; PA-5T / 5I; PA-6; PA-6,6; PA-6,6 / 6; PA-6.6 / 6T; PA-6T / 6I; PA-6T / 6P6; PA-6T / 6; PA-6T / 6V66; PA-6T / MPDMT (where MPDMT is polyamide based on a mixture of hexamethylene diamine and 2-methylpentamethylene diamine as the diamine component and terephthalic acid as the diacid component); PA-6T / 66; PA-6T / 610; PA-10T / 612; PA-10T / 106; PA-6T / 612; PA-6T / 10T; PA-6T / 10I; PA-9T; PA-10T; PA-12T; PA-10T / 10I; PA-10T / 12; PA-10T / 11; PA-6T / 9T; PA-6T / 12T; PA-6T / 10T / 6I: PA-6T / 6P6: PA-6T / 61 / 12; and combinations thereof.

[0052] The polyamides of the flame retardant composition may include, for example, PA-66; PA-6; PA-66 / 6; PA-66 / 6T; PA-66 / 61; PA-66 / 6C; PA-9T; PA-10T; PA-12T; or PA-6T / 9T; or combinations or copolymers thereof. Particularly suitable polyamides for use in the flame retardant polyamide composition may include PA-6, PA-66, PA-6 / PA-66 copolymers, PA-6,6 / 61, PA-6I / 6T, PA-6,6 / 6T, PA- 12, PA-610, or PA-612, or combinations thereof. In some embodiments, the polyamides of the flame retardant composition do not contain aromatic components.

[0053] The flame retardant polyamide composition may contain from 5 wt.% to 85 wt.% polyamide, based on the total weight of the flame retardant polyamide composition, for example, from 10 wt.% to 80 wt.%, from 15 wt.% to 75 wt.%, from 20 wt.% to 70 wt.%, from 25 wt.% to 65 wt.%, from 30 wt.% to 60 wt.%, from 35 wt.% to 55 wt.%, or from 40 wt.% to 50 wt.%. In terms of upper limits, the flame retardant polyamide composition may contain less than 85 wt.% polyamide, e.g., less than 80 wt.%, less than 75 wt.%, less than 70 wt.%, less than 65 wt.%, less than 60 wt.%, less than 55 wt.%, less than 50 wt.%, or less than 45 wt.%. In terms of lower limits, the flame retardant polyamide composition may contain greater than 5 wt.% polyamide, e.g., greater than 10 wt.%, greater than 15 wt.%, greater than 20 wt.%. greater than 25 wt.%, greater than 30 wt.%, greater than 35 wt.%, or greater than 40 wt.%.

[0054] In some cases, the flame retardant polyamide composition may contain PA-6 in an amount ranging from 10 wt.% to 50 wt.% of the total flame retardant polyamide composition, for example, from 15 wt.% to 45 wt.%, from 20 wt.% to 40 wt.%, or from 25 wt.% to 35 wt.%. In terms of upper limits, the flame retardant polyamide composition may contain PA-6 in an amount less than 50 wt.%, e.g., less than 45 wt.%, less than 40 wt.%, less than 35 wt.%, or less than 30 wt.%. In terms of lower limits, the flame retardant polyamide composition may contain PA-6 in an amount greater than 10 wt.%, e.g., greater than 15 wt.%, greater than 20 wt.%, or greater than 25 wt.%.

[0055] In some cases, the flame retardant polyamide composition may contain PA-66 in an amount ranging from 10 wt.% to 50 wt.% of the total flame retardant polyamide composition, for example, from 15 wt.% to 45 wt.%. from 20 wt.% to 40 wt.%, or from 25 wt.% to 35 wt.%. In terms of upper limits, the flame retardant polyamide composition may contain PA-66 in an amount less than 50 wt.%, e.g., less than 45 wt.%, less than 40 wt.%, less than 35 wt.%, or less than 30 wt.%. In terms of lower limits, the flame retardant polyamide composition may contain PA-66 in an amount greater than 10 wt.%, e.g., greater than 15 wt.%, greater than 20 wt.%, or greater than 25 wt.%.

[0056] Other additives

[0057] In some embodiments, the polyamide composition can optionally include one or more additive(s). In some embodiments, the additives include one or more of catalyst, polymers other than polyamide, adhesion promoters, ions, compounds, preservatives such as heat stabilizers and antioxidants, lubricants, flow enhancers, or other ingredients as known in the art. The additive(s) may include at least one of: inorganic stabilizers, organic stabilizers, lubricants, dyes, pigments, nucleating agents, metal flakes, impact modifiers, antistatic agents, conductivity additives, mold-release agents, optical brighteners, adhesion promoters, ageing inhibitors, antioxidants, antiozonants, light stabilizers, ultraviolet (UV) stabilizers, UV absorbers, UV blockers, inorganic heat stabilizers, organic heat stabilizers, processing aids, crystallization accelerators, crystallization retarders, and flow aids.

[0058] In some embodiments, the polyamide composition includes one or more lubricants selected to serve as processing aids. The type and relative amount of lubricant can be selected to improve processing of the polyamide composition, and to contribute to the high strength of the material. In some embodiments, the lubricant includes a wax. In some embodiments, the lubricant consists of a wax. In some embodiments, the wax includes a fatty acid. In some embodiments, the lubricant consists of a fatty acid. In some embodiments, the wax includes a saturated fatty acid. In some embodiments, the lubricant consists of a saturated fatty acid. In some embodiments, the wax includes stearic acid, behenic acid, or salts or combinations thereof. In some embodiments, the lubricant consists of stearic acid, behenic acid, or salts or combinations thereof. The stearate lubricant can include, for example, zinc stearate calcium stearate, aluminum distearate, zinc stearate, and / or calcium stearate.

[0059] In some embodiments, the combined concentration of the one or more lubricants of the polyamide composition ranges from 0.1 wt.% to 2 wt.%, e.g., from 0.1 wt.% to 0.6 wt.%, from 0.13 wt.% to 0.81 wt.%, from 0.18 wt.% to 1.1 wt.%, from 0.25 wt.% to 1.5 wt.%, or from 0.33 wt.% to 2 wt.%. In terms of upper limits, the lubricant concentration can be less than 2 wt.%, e.g., less than 1.5 wt.%, less than 1.1 wt.%, less than 0.81 wt.%. less than 0.6 wt.%, less than 0.45 wt.%. less than 0.33 wt.%, less than 0.25 wt.%, less than 0.18 wt.%, or less than 0.13 wt.%. In terms of lower limits, the lubricant concentration can be greater than 0.1 wt.%, e.g., greater than 0.13 wt.%, greater than 0.18 wt.%, greater than 0.25 wt.%, greater than 0.33 wt.%, greater than 0.45 wt.%, greater than 0.6 wt.%, greater than 0.81 wt.%, greater than 1.1 wt.%, or greater than 1.5 wt.%. Higher concentrations, e.g., greater than 2 wt.%, and lower concentrations, e.g., less than 0.1 wt.%, are also contemplated.

[0060] In some embodiments, the polyamide composition is free of additives. For example, in some embodiments, the polyamide composition consists essentially of the polyamide, the first mineral flame retardant, the second mineral flame retardant, and the reinforcing agent. In some embodiments, the polyamide composition consists of the polyamide, the first mineral flame retardant, the second mineral flame retardant, and the reinforcing agent.

[0061] Unlike conventional polyamide compositions, present embodiments do not require exogenous nucleating agents. Instead, Applicant recognized that the high loading of minerals in the formulations described herein may be used to control the crystallization kinetics of the polyamide resins, thereby negating the need for exogenous nucleating agents.

[0062] Performance Characteristics

[0063] As discussed above, the flame retardant polyamide compositions disclosed herein surprisingly demonstrate both flame retardancy and superior mechanical properties. One measurement of flame retardancy is the UL94 standard, in which a specimen is supported in a vertical position and a flame is applied to the bottom of the specimen. The flame is applied for ten seconds and then removed until flaming stops, at which time the flame is reapplied for another ten seconds and then removed. Two sets of five specimens are tested. The samples are generally tested at different widths, for example, 0.4 mm, 0.8 mm, and 1.6 mm. The two sets are conditioned before and after aging. For unaged testing, each thickness is tested after conditioning for 48 hours at 23 °C and 50% relative humidity. For aged testing, five samples of each thickness are tested after conditioning for 7 days at 70 °C. The disclosed compositions may demonstrate a V0 or VI or V2 score. Specifically, the flame retardant polyamide composition described herein may demonstrate a passing value of V2 for UL94 performance at both 1.6 mm and 3.2 mm.

[0064] Glow Wire Flammability Index Test (“GWFI”)

[0065] In the GWFI test, a glowing wire is used at temperatures of 550 °C to 960 °C to determine, on 3 test specimens of different widths (for example, 0.4 mm, 0.8 mm, and 1.6 mm), at which an afterflame time of 30 seconds is not exceeded and no flaming drops come from the specimen. This test is performed in accordance with IEC 60695-2-12. The disclosed compositions may demonstrate a passing GWFI score at the desired temperature.

[0066] Comparative Tracking Index (“CTI”)

[0067] The comparative tracking index may be determined in accordance with International Standard IEC 60112-2003 to provide a quantitative indication of the ability of a composition to perform as an electrical insulating material under wet and / or contaminated conditions. In determining the CTI rating ofa composition, two electrodes are placed on a molded test specimen. A voltage differential is then established between the electrodes while a 0.1 % aqueous ammonium chloride solution is dropped onto a test specimen. The maximum voltage at which five specimens withstand the test period for 50 drops without failure is determined. The test voltages range from 100 volts (V) to 600 V in 25 V increments. The numerical value of the voltage that causes failure with the application of fifty (50) drops of the electrolyte is the CTI. The value provides an indication of the relative track resistance of the material. An equivalent method for determining the CTI is ASTM D-3638-12.

[0068] Mechanical Properties

[0069] In addition to flame retardancy, the compositions disclosed herein may demonstrate desirable mechanical properties, such as impact resistance and tensile strength. Specifically, the flame retardant polyamide composition may demonstrate a tensile strength at break greater than 1.8%, e.g., greater than 1.9%, greater than 2.0%, greater than 2.1%, greater than 2.2%, greater than 2.3%, greater than 2.4%, or greater than 2.5%, as measured by ISO Test No. 527:2012.

[0070] The flame retardant polyamide composition may demonstrate a tensile stress at break (at 5 millimeters per minute (mm / min)) of greater than 86 megapascal (MPa), e.g., greater than 87 MPa, greater than 88 MPa, greater than 89 MPa, greater than 90 MPa, greater than 91 MPa, greater than 92 MPa, greater than 93 MPa, greater than 94 MPa, or greater than 95 MPa, as measured by ISO Test No. 527:2012.

[0071] The flame retardant polyamide composition may demonstrate an elasticity modulus (at 1 mm / min) of greater than 8400 MPa. e.g., greater than 8450 MPa, greater than 8500 MPa, greater than 8550 MPa, greater than 9000 MPa, or greater than 9500 MPa, as measured by ISO Test No. 527:2012.

[0072] The flame retardant polyamide composition may demonstrate flexural stress (at 2 mm / min) of greater than 145 MPa. e.g., greater than 146 MPa, greater than 147 MPa, greater than 148 MPa. greater than 149 MPa, greater than 150 MPa, greater than 151 MPa, greater than 152 MPa, greater than 153 MPa, greater than 154 MPa, or greater than 155 MPa, as measured by ISO Test No. 178.

[0073] The flame retardant polyamide composition may further demonstrate a flexural modulus (at 2mm / min) of greater than 7500 MPa, e.g., greater than 7550 MPa, greater than 8000 MPa, greater than 8500 MPa, or greater than 9000 MPa, as measured by ISO Test No. 178.

[0074] The impact resistance may be demonstrated by Charpy notched and unnotched tests, as well as the Izod notched test. The flame retardant polyamide composition may demonstrate an impact resistance of greater than 30 kJ / m2, e.g., greater than 31 kJ / m2, greater than 32 kJ / m2, greater than 33 kJ / m2, greater than34 kJ / m2, greater than 35 kJ / m2, greater than 36 kJ / m2, greater than 37 kJ / m2, greater than 38 kJ / m2,greater than 39 kJ / m2, greater than 40 kJ / m2, greater than 41 kJ / m2, greater than 42 kJ / m2, greater than 43 kJ / m2, greater than 44 kJ / m2, greater than 45 kJ / m2, greater than 46 kJ / m2, greater than 47 kJ / m2, greater than 48 kJ / m2, greater than 49 kJ / m2, greater than 50 kJ / m2, greater than 51 kJ / m2, greater than 52 kJ / m2, greater than 53 kJ / m2, greater than 54 kJ / m2, or greater than 55 kJ / m2, as measured using Charpy unnotched resistance described in ISO 179-1 (2010).

[0075] As used herein, “greater than” and “less than” limits may also include the number associated therewith. Stated another way, “greater than” and “less than” may be interpreted as “greater than or equal to” and “less than or equal to.” It is contemplated that this language may be subsequently modified in the claims to include “or equal to.” For example, “greater than 4.0” may be interpreted as, and subsequently modified in the claims as “greater than or equal to 4.0.”

[0076] In some embodiments, any or some of the components or steps disclosed herein may be considered optional. In some cases, the disclosed compositions may expressly exclude any or some of the aforementioned components or steps in this description, for example, via claim language. For example, claim language may be modified to recite that the disclosed compositions, materials processes, etc., do not utilize or comprise one or more of the aforementioned components. For example, the claim language may be modified to recite that the disclosed materials do not comprise a reinforcing agent. Such negative limitations are contemplated, and this text serves as support for negative limitations for components, steps, and / or features.

[0077] Examples

[0078] The present disclosure will be better understood in view of the following non-limiting examples. The following examples are intended for illustrative purposes only and do not limit in any way the scope of the present disclosure.

[0079] Examples 1 -5 and Comparative Example A

[0080] Five flame retardant polyamide compositions according to the present disclosure (Examples 1-5) having to components shown below in Table 1 were prepared. All polyamide compositions were prepared on a laboratory scale co-rotating twin screw extruder BC-21 (available from Clextral) and subsequently molded into ISO specimens via an injection molding process.

[0081] In Example 1, the boehmite (i.e., ACTILOX® 200SM) was not treated with amino silane. Examples 2-5 contained amino silane treated boehmite (i.e., ACTILOX® 200AS1). The magnesium hydroxide (i.e., MAGNIFIN® H-5 IV) and wollastonite (i.e., WICROLL® 10PA) were amino silane treated minerals in Examples 1-5 and Comparative Example A. Comparative Example A was preparedwithout a second mineral flame retardant, as shown below in Table 1. The flame retardant minerals used in these examples (with or without amino silane treatment) contained less than 5 wt.% halogens, less than 5 wt.% phosphorous, less than 5 wt.% nitrogen, and less than 5 wt.% carbon. More specifically, the flame retardant minerals used in these examples (with or without amino silane treatment) contained less than 0.1 wt.% halogens, less than 0.1 wt.% phosphorous, less than 0.1 wt.% nitrogen, and less than 5 wt.% carbon.

[0082] Table 1. Composition of Examples 1-5 and Comparative Example A.

[0083] All compositions were then tested for various mechanical properties. The results are shown below in Table 2.

[0084] Table 2. Material Properties of Examples 1-5 and Comparative Example A.

[0085] The compositions were further tested for combustibility according to the UL94 standard and GWFI tests, as described above. Electrical properties were evaluated according to CTI testing, as described above. The results are shown below in Table 3.

[0086] Table 3. Flame retardancy, GWFI, and CTI Properties of Examples 1-5 and Comparative Example A.> > > > > >

[0087] Example 7

[0088] The properties of the components were then examined for their contribution to flame retardancy, mechanical properties (elongation at break), and electrical properties (CTI). The results are shown below in Table 4, in which ratings were determined on a scale from very detrimental (— ) to very desirable (+++), with a score of 0 showing no effect.

[0089] Table 4. Effects of Components on Properties of Polyamide Compositions.

[0090] As shown in the above examples, the flame retardant polyamide compositions described herein provide excellent flame retardancy while maintaining or exceeding the mechanical properties of conventional formulations, without the need for toxic or environmentally harmful components. Further, the use of two surface treated mineral flame retardants in conjunction with acicular wollastonite demonstrates a synergistic effect, improving mechanical performance even over compositions containing only one mineral flame retardant, as demonstrated by impact resistance using the Charpy unnotched test.

[0091] Embodiments

[0092] The following embodiments are contemplated. All combinations of features and embodiments are contemplated.

[0093] Embodiment 1 is a flame retardant polyamide composition comprising: a polyamide; a flame retardant package comprising: from 5 wt.% to 30 wt.% of a first mineral flame retardant, based on the total weight of the flame retardant polyamide composition, and from 5 wt.% to 30 wt.% of a second mineral flame retardant, based on the total weight of the flame retardant polyamide composition; and areinforcing agent; wherein the flame retardant package comprises less than 5 wt.% halogens, less than 5 wt.% phosphorous, and less than 5 wt.% nitrogen; and wherein the total mineral content of the flame retardant polyamide composition is greater than 30 wt.%.

[0094] Embodiment 2 is the flame retardant polyamide composition has a tensile strength at break greater than 1.8%, as measured by ISO Test No. 527:2012, and an impact resistance greater than 30 kJ / m2, as measured using Charpy unnotched resistance described in ISO 179-1 (2010).

[0095] Embodiment 3 is the flame retardant polyamide composition of either Embodiment 1 or Embodiment 2, wherein the flame retardant package comprises less than 5 wt.% carbon, less than 0.1 wt.% halogens, less than 0.1 wt.% phosphorous, and / or less than 0.1 wt.% nitrogen.

[0096] Embodiment 4 is the flame retardant polyamide composition of any of Embodiments 1-3, wherein the first mineral flame retardant comprises magnesium hydroxide.

[0097] Embodiment 5 is the flame retardant polyamide composition of Embodiment 4, wherein the magnesium hydroxide is an amino silane treated magnesium hydroxide.

[0098] Embodiment 6 is the flame retardant polyamide composition of any of Embodiments 1-5, wherein the second mineral flame retardant comprises boehmite.

[0099] Embodiment 7 is the flame retardant polyamide composition of any of Embodiments 1-6, wherein the reinforcing agent comprises glass fibers, wollastonite, talc, mica, or clay, or any combination thereof.

[0100] Embodiment 8 is the flame retardant polyamide composition of Embodiment 7, wherein the reinforcing agent is an amino silane treated reinforcing agent.

[0101] Embodiment 9 is the flame retardant polyamide composition of any of Embodiments 1-8, comprising from 5 wt.% to 85 wt.% polyamide, based on the total weight of the flame retardant polyamide composition.

[0102] Embodiment 10 is the flame retardant polyamide composition of any of Embodiments 1-9, wherein the polyamide comprises PA-6, PA-66, PA-6 / PA-66 copolymers. PA-6,6 / 61, PA-6I / 6T, PA-6,6 / 6T, PA- 12, PA-610, or PA-612, or any combination thereof.

[0103] Embodiment 11 is the flame retardant polyamide composition of Embodiment fO, wherein the polyamide comprises polyamide 6 (PA-6), or polyamide 6,6 (PA-66), or any combination thereof.

[0104] Embodiment 12 is the flame retardant polyamide composition of Embodiment 11, wherein the polyamide comprises PA-6 in an amount ranging from 10 wt.% to 50 wt.% of the total flame retardant polyamide composition.

[0105] Embodiment 13 is the flame retardant polyamide composition of Embodiment 11 , wherein the polyamide comprises PA-66 in an amount ranging from 10 wt.% to 50 wt.% of the total flame retardant polyamide composition.

[0106] Embodiment 14 is the flame retardant polyamide composition of Embodiment 8, wherein the reinforcing agent comprises needle-shaped reinforcing agents.

[0107] Embodiment 15 is the flame retardant polyamide composition of any of Embodiments 1-14, wherein the flame retardant polyamide composition demonstrates a passing value for a glow wire flammability test as measured by IEC 60695-2-12 at a temperature of at least 850 °C and at a width of 1.6 mm.

[0108] Embodiment 16 is the flame retardant polyamide composition of any of Embodiments 1-15, wherein the flame retardant polyamide composition demonstrates a passing value of at least V2 (rating) for UL94 performance at a width of 1.6 mm and 3.2 mm.

[0109] Embodiment 17 is the flame retardant polyamide composition of any of Embodiments 1-16, further comprising an additive, wherein the additive comprises stabilizers, colorants, lubricants, antioxidants, or light stabilizers, or any combination thereof.

[0110] Embodiment 18 is a flame retardant polyamide composition consisting of: a polyamide; a flame retardant package comprising: from 5 wt.% to 30 wt.% of a treated magnesium hydroxide, based on the total weight of the flame retardant polyamide composition, and from 5 wt.% to 30 wt.% boehmite, based on the total weight of the flame retardant polyamide composition; and a wollastonite reinforcing agent; wherein the flame retardant polyamide composition has a tensile strength at break greater than 1.8%, as measured by ISO Test No. 527:2012, and an impact resistance of greater than 30 kJ / m2, as measured using Charpy unnotched resistance described in ISO 179-1 (2010).

[0111] Embodiment 19 is a flame retardant polyamide composition comprising: a polyamide; a flame retardant package comprising: from 5 wt.% to 30 wt.% of a treated magnesium hydroxide, based on the total weight of the flame retardant polyamide composition and from 5 wt.% to 30 wt.% boehmite, based on the total weight of the flame retardant polyamide composition; and a wollastonite reinforcing agent; wherein the flame retardant package contains less than 2 wt.% halogens; less than 2 wt.% phosphorous; less than 2 wt.% nitrogen; less than 2 wt.% carbon; wherein the total mineral content of the flame retardant polyamide composition is greater than 30 wt.%; and wherein the flame retardant polyamide composition has a tensile strength at break greater than 1.8%, as measured by ISO Test No. 527:2012, and an impactresistance of greater than 30 kJ / m2, as measured using Charpy unnotched resistance described in TSO 179-1 (2010).

[0112] Embodiment 20 is the flame retardant polyamide composition of Embodiment 19, wherein the boehmite of the flame retardant package, the wollastonite reinforcing agent, or both, are amino silane treated materials.

[0113] Other objects, features, and advantages of the disclosure will become apparent from the foregoing figures, detailed description, and examples. The figures, detailed description, and examples, while indicating specific embodiments of the disclosure, are given by way of illustration only and are not meant to be limiting. Additionally, it is contemplated that changes and modifications within the spirit and scope of the disclosure will become apparent to those skilled in the art from the detailed description. In further embodiments, features from specific embodiments may be combined with features from other embodiments. For example, features from one embodiment may be combined with features from any of the other embodiments. In further embodiments, additional features may be added to the specific embodiments described herein.

Claims

CLAIMSWhat is claimed is:

1. A flame retardant polyamide composition comprising:a polyamide;a flame retardant package comprising:from 5 wt.% to 30 wt.% of a first mineral flame retardant, based on the total weight of the flame retardant polyamide composition, andfrom 5 wt.% to 30 wt.% of a second mineral flame retardant, based on the total weight of the flame retardant polyamide composition; anda mineral reinforcing agent,wherein the flame retardant package comprises less than 5 wt.% halogens, less than 5 wt.% phosphorous, and less than 5 wt.% nitrogen, andwherein the total mineral content of the flame retardant polyamide composition is greater than 30 wt.%.

2. The flame retardant polyamide composition of claim 1, wherein the flame retardant polyamide composition has a tensile strength at break greater than 1.8%, as measured by ISO Test No.527:2012, and an impact resistance greater than 30 kJ / m2, as measured using Charpy unnotched resistance described in ISO 179-1 (2010).

3. The flame retardant polyamide composition of claim 1, wherein the flame retardant package comprises less than 5 wt.% carbon, less than 0.1 wt.% halogens, less than 0.1 wt.% phosphorous, and / or less than 0.1 wt.% nitrogen.

4. The flame retardant polyamide composition of claim 1, wherein the first mineral flame retardant comprises magnesium hydroxide.

5. The flame retardant polyamide composition of claim 4, wherein the magnesium hydroxide is an amino silane treated magnesium hydroxide.

6. The flame retardant polyamide composition of claim 1, wherein the second mineral flame retardant comprises boehmite.

7. The flame retardant polyamide composition of claim 1, wherein the reinforcing agent comprises glass fibers, wollastonite, talc, mica, or clay, or any combination thereof.

8. The flame retardant polyamide composition of claim 7, wherein the reinforcing agent is an amino silane treated reinforcing agent.

9. The flame retardant polyamide composition of claim 1 , comprising from 5 wt.% to 85 wt.% polyamide, based on the total weight of the flame retardant polyamide composition.

10. The flame retardant polyamide composition of claim 1, wherein the polyamide comprises PA-6, PA-66, PA-6 / PA-66 copolymers. PA-6,6 / 61. PA-6U6T. PA-6.6 / 6T, PA- 12, PA-610, or PA-612, or any combination thereof.

11. The flame retardant polyamide composition of claim 10, wherein the polyamide comprises polyamide 6 (PA-6), or polyamide 6,6 (PA-66), or any combination thereof.

12. The flame retardant polyamide composition of claim 11, wherein the polyamide comprises PA-6 in an amount ranging from 10 wt.% to 50 wt.% of the total flame retardant polyamide composition.

13. The flame retardant polyamide composition of claim 11, wherein the polyamide comprises PA-66 in an amount ranging from 10 wt.% to 50 wt.% of the total flame retardant polyamide composition.

14. The flame retardant polyamide composition of claim 8. wherein the reinforcing agent comprises needle-shaped reinforcing agents.

15. The flame retardant polyamide composition of claim 1 , wherein the flame retardant polyamide composition demonstrates a passing value for a glow wire flammability test, as measured by IEC 60695-2-12 at a temperature of at least 850 °C and at a width of 1.6 mm.

16. The flame retardant polyamide composition of claim 1 , wherein the flame retardant polyamide composition demonstrates a passing value of at least V2 (rating) for UL94 performance at a width of 1.6 mm and 3.2 mm.

17. The flame retardant polyamide composition of claim 1, further comprising an additive, wherein the additive comprises stabilizers, colorants, lubricants, antioxidants, or light stabilizers, or any combination thereof.

18. A flame retardant polyamide composition consisting of:a polyamide;a flame retardant package comprising:from 5 wt.% to 30 wt.% of a treated magnesium hydroxide, based on the total weight of the flame retardant polyamide composition, andfrom 5 wt.% to 30 wt.% boehmite, based on the total weight of the flame retardant polyamide composition; anda wollastonite reinforcing agent,wherein the flame retardant polyamide composition has a tensile strength at break greater than 1.8%, as measured by ISO Test No. 527:2012, and an impact resistance of greater than 30 kJ / m2, as measured using Charpy unnotched resistance described in ISO 179-1 (2010).

19. A flame retardant polyamide composition comprising:a polyamide;a flame retardant package comprising:from 5 wt.% to 30 wt.% of an amino silane treated magnesium hydroxide, based on the total weight of the flame retardant polyamide composition, andfrom 5 wt.% to 30 wt.% boehmite, based on the total weight of the flame retardant polyamide composition; anda wollastonite reinforcing agent,wherein the flame retardant package contains less than 2 wt.% halogens, less than 2 wt.% phosphorous, less than 2 wt.% nitrogen, and less than 2 wt.% carbon,wherein the total mineral content of the flame retardant polyamide composition is greater than 30 wt.%, andwherein the flame retardant polyamide composition has a tensile strength at break greater than 1.8%, as measured by ISO Test No. 527:2012, and an impact resistance of greater than 30 kJ / m2, as measured using Charpy unnotched resistance described in ISO 179-1 (2010).

20. The flame retardant polyamide composition of claim 19, wherein the boehmite of the flame retardant package, the wollastonite reinforcing agent, or both, are amino silane treated materials.

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