Aluminium trihydroxide compositions

Abstract

This invention relates to aluminum trihydroxide compositions. This invention also relates to methods for forming aluminum trihydroxide compositions.

Description

Technical Field

[0001] This invention relates to aluminum trihydroxide compositions. This invention also relates to methods for forming aluminum trihydroxide compositions. Prior Technology

[0002] Aluminum trioxide (ATH) compositions are commonly used as flame retardants in a wide range of materials, including, but not limited to, wires, cables, furniture, transportation equipment, electronics, and building materials. Essentially, ATH acts as a thermally conductive filler in a polymer matrix (i.e., in a composite with a polymer) derived from polysiloxanes, epoxides, polyesters, and / or polyols.

[0003] Because ATH is a white powder with desirable heat dissipation, good density (basically 2.42 g / cm3 plus or minus 0.2 g / cm3) and non-conductive nature related to electric current, it is a good flame retardant.

[0004] ATH compositions may include ATH particles having two or more different physical properties (e.g., two or more different particle sizes, two or more different particle size distributions, and / or two or more different morphologies). When the resulting ATH composition is used in a polymer matrix, i.e., included in a polymer composite, the combination of ATH particles having two or more different physical properties provides excellent properties regarding thermal conductivity and viscosity.

[0005] The known ATH composition is APYRAL™ 20X, produced by Nabaltec AG. APYRAL™ 20X is believed to be a combination of milled and precipitated ATH particles. When used in polymer composites, APYRAL™ 20X exhibits favorable viscosity and thermal conductivity.

[0006] There is a demand for ATH compositions with favorable thermal conductivity and viscosity properties. Summary of the Invention

[0007] This invention relates to ATH compositions that can be used to replace, in whole or in part, known ATH compositions.

[0008] The ATH composition of the present invention advantageously has the same or similar physical properties as known ATH compositions.

[0009] This invention relates to an ATH composition comprising a combination of milled ATH particles having at least two different physical properties. This new ATH composition advantageously possesses superior thermal conductivity compared to known ATH compositions, and advantageously maintains the same or similar physical properties as known ATH compositions.

[0010] The representative features of the present invention are set forth in the following clauses, which may stand alone or may be combined in any combination with one or more features disclosed in the text and / or figures of the specification.

[0011] A first feature of the present invention is that an aluminum hydroxide composition is provided, wherein the aluminum hydroxide composition comprises (or is composed of): The first plurality of milled aluminum hydroxide particles, ranging from 50 wt% to 85 wt%, have a maximum size of 50 to 500 µm; A second plurality of milled aluminum hydroxide particles, ranging from 15% to 50% by weight, having a maximum size of less than 50 µm; and, optionally, Impurities that cannot be avoided.

[0012] Preferably, the maximum size of the first plurality of milled aluminum hydroxide particles is: from 50 to 300 µm; or, from 75 to 250 µm; or, from 100 to 150 µm (plus or minus 50 µm).

[0013] More preferably, the maximum size of the second plurality of milled aluminum hydroxide particles is: less than 40 µm; or, less than 30 µm (plus or minus 5 µm).

[0014] Advantageously, wherein the first plurality of milled ATH particles have: D10 of 25 to 40 µm; or 25 to 35 µm; or 31 to 33 µm; or 32 µm; and / or, D50 of 90 to 110 µm; or 100 to 104 µm; or 102 µm; and / or, D97 ranging from 200 to 300 µm; or from 200 to 220 µm; or 210 µm.

[0015] Preferably, the second plurality of milled ATH particles have: D10 of 1.0 to 4.0 µm; or 1.0 to 2.0 µm; or 1.5 µm; and / or, D50 of 6 to 12 µm; or 8 µm; and / or, D97 ranging from 25 to 40 µm; or from 30 to 34 µm; or 32 µm.

[0016] More preferably, the aluminum hydroxide composition has: D10 of 1 to 3 µm; or 2 µm; and / or, D50 of 20 to 24 µm; or 21.86 µm; and / or, D97 ranges from 180 to 220 µm; or 198 µm.

[0017] Preferably, the total cumulative volume of the first plurality of milled aluminum hydroxide particles is: 76 mm3 / g or less; or, from 76 mm3 / g to 50 mm3 / g; or, from 76 mm3 / g to 65 mm3 / g.

[0018] More preferably, the specific surface area of ​​the first plurality of ground aluminum hydroxide particles is: 3 m2 / g or less; or 2.95 m2 / g or less; or from 3 m2 / g to 1 m2 / g; or from 2.95 m2 / g to 2.8 m2 / g.

[0019] Advantageously, the aluminum hydroxide composition comprises the first plurality of milled aluminum hydroxide particles in an amount of: 60 to 85% by weight; or, 65 to 80% by weight; or, 70 to 80% by weight; or, 55 to 65% by weight.

[0020] Preferably, the aluminum hydroxide composition contains the second plurality of milled ATH particles in an amount of 15 to 40% by weight; or 20 to 35% by weight; or 20 to 30% by weight; or 35 to 45% by weight.

[0021] More preferably, in which: The maximum size of the first plurality of milled aluminum hydroxide particles is 300 µm; and, The maximum size of the second plurality of milled aluminum hydroxide particles is 30µm.

[0022] Advantageously, the ratio of the first plurality of ground aluminum hydroxide particles to the second plurality of ground aluminum hydroxide particles in the aluminum hydroxide composition is (in weight %): 12.5 (first): 3.5 (second), each plus or minus 2.5; or, 8 (first): 1.5 (second), each plus or minus 0.5; or, 10 (first): 5 (second), each plus or minus 1; or, 4 (first): 2.2 (second), each plus or minus 0.5.

[0023] Preferably, the ratio of the first plurality of milled aluminum hydroxide particles to the second plurality of milled aluminum hydroxide particles results in: the aluminum hydroxide composition having 40 volume / volume% or less of voids (or pores); or, the aluminum hydroxide composition having 34 volume / volume% or less of voids (or pores).

[0024] More preferably, the density of the aluminum hydroxide composition is 2.42 g / cm3 (plus or minus 0.2 g / cm3).

[0025] Advantageously, the first plurality of milled ATH particles and the second plurality of milled ATH particles in the aluminum hydroxide composition have a uniform particle distribution.

[0026] Preferably, the maximum particle size distribution in the aluminum hydroxide composition ranges from 0.1 to 305 µm.

[0027] According to another feature of the present invention, a method for manufacturing an aluminum hydroxide composition is provided, the method comprising the following steps: Provided are first plurality of milled aluminum hydroxide particles, the maximum size of which is from 50 to 500 µm in 50% to 85% by weight; and Provided a second plurality of milled aluminum hydroxide particles, the maximum size of which is less than 50 µm in a range of 15 wt% to 50 wt%; and The first plurality of ground aluminum hydroxide particles and the second plurality of ground aluminum hydroxide particles are mixed.

[0028] Preferably, the aluminum hydroxide composition, the first plurality of milled aluminum hydroxide particles and / or the second plurality of milled aluminum hydroxide particles are any one of claims 1 to 14.

[0029] More preferably, the mixing step is carried out as follows: from 0.1 to 8 hours at 25°C; or, from 0.3 to 4 hours at 25°C; or, from 0.5 to 2 hours at 25°C; or, until a mixture with uniform particle distribution is formed at 25°C.

[0030] Advantageously, the ratio of the first plurality of ground aluminum hydroxide particles to the second plurality of ground aluminum hydroxide particles in the mixture is (in weight %): 12.5 (first): 3.5 (second), each plus or minus 2.5; or, 8 (first): 1.5 (second), each plus or minus 0.5; or, 10 (first): 5 (second), each plus or minus 1; or, 4 (first): 2.2 (second), each plus or minus 0.5.

[0031] According to another feature of the invention, the aluminum trioxide composition is used as a flame retardant and / or as a thermal management filler.

[0032] According to another feature of the present invention, a polymer composite is provided, comprising a polymer and the aluminum hydroxide composition of the present invention.

[0033] Preferably, the polymer is a polymer formed from polysiloxane, epoxide, polyester, polyethylene wax and / or polyol; optionally, the polymer is a thermosetting polymer or a thermoplastic polymer.

[0034] More preferably, the polymer composite comprises (in weight %): 50 to 90% by weight of aluminum hydroxide composition as claimed in any one of items 1 to 14; and, 10 to 50% by weight of polymer; or 60 to 80% by weight of aluminum hydroxide composition as claimed in any one of items 1 to 14; and, 20 to 40% by weight of polymer.

[0035] Advantageously, the thermal conductivity of the polymer composite is: from 2 to 7 W / mK; or from 2 to 4 W / mK; or from 2.5 to 3 W / mK; or from 2.6 to 2.9 W / mK; or from 2.8 to 2.9 W / mK.

[0036] Preferably, the viscosity of the polymer composite is: 13 Pa·s or less; or, 11 Pa·s or less; or, 9 Pa·s or less.

[0037] The embodiments of this disclosure will be described more fully below with reference to the accompanying drawings, in which similar numbers in several figures represent similar elements and illustrative embodiments are given. However, embodiments of the claims may be embodied in many different forms and should not be limited to the embodiments set forth herein.

[0038] The accompanying drawings illustrate various embodiments of the system, method, and various other features of this disclosure. Those skilled in the art will understand that the element boundaries (e.g., boxes, groups of boxes, or other shapes) shown in the figures represent an example of a boundary. In some instances, one element may be designed as multiple elements or multiple elements may be designed as one element. In some instances, an element shown as an internal component of one element may be an external component of another element, and vice versa. Furthermore, elements may not be drawn to scale. A non-limiting and non-exhaustive description is described with reference to the following drawings. Components in the drawings are not necessarily drawn to scale, but are emphasized to illustrate principles. Simple Explanation of the Diagram

[0039] [Figure 1] is a scanning electron microscope (SEM) image showing the morphology of the first (coarse-grained) plurality of ground ATH particles.

[0040] [Figure 2] is a SEM image showing the morphology of the second (fine-grained) multiple milled ATH particles.

[0041] [Figure 3] shows the pore size distribution of the first (coarse) plurality of ground ATH particles (the first (coarse) plurality of ground ATH particles contained in the composition of ATHE1, ATHE2 and ATHE3; referred to as coarse particles A).

[0042] [Figure 4] shows the pore size distribution of the first (coarse) plurality of ground ATH particles (the first (coarse) plurality of ground ATH particles contained in the BORATHERMTMSG-200LVS composition; referred to as coarse particles B).

[0043] [Figure 5] is a SEM image showing the morphology of multiple ground ATH particles (coarse particles A) in the first (coarse) layer of Figure 3.

[0044] [Figure 6] is a SEM image showing the morphology of multiple ground ATH particles (coarse particles B) in the first (coarse) layer of Figure 4.

[0045] [Figure 7] is a graph showing the particle size distribution of the exemplary ATH composition as a cumulative curve (summing up to 100).

[0046] [Figure 8] is a plot of the particle size distribution of the same ATH composition as in Figure 7, shown as a relative distribution.

[0047] [Figure 9] is a viscosity diagram of three different ATH compositions of the present invention, which contain different proportions of a first (coarse) plurality of ground ATH particles and a second (fine) plurality of ground ATH particles. Implementation

[0048] The terms “comprising,” “having,” “containing,” and “including,” and their other forms, are intended to be equivalent in meaning and are open-ended. The one or more items following any of these terms are not an exhaustive list of those items, or are limited to the one or more items listed. Terms should not be construed as excluding the presence of other features, steps, or components. It must also be noted that, unless the context clearly specifies otherwise, as used herein and in the claims of the appended patent applications, the singular forms “a,” “an,” and “the” include the plural forms. While any systems and methods similar to or equivalent to those described herein may be used for implementation or testing of the embodiments disclosed herein, preferred systems and methods are described hereafter.

[0049] The following lists some terms used to describe this invention:

[0050] Aluminum trihydride (ATH) is an inorganic mineral with the chemical formula Al(OH)3. It exists naturally primarily as gibbsite and in three rare polymorphs: bayerite, doyleite, and nordstrandite. Aluminum trihydride is also commonly referred to as aluminum hydroxide.

[0051] "APYRAL™ 20X" refers to a product currently sold by Nabaltec AG. APYRAL™ 20X is a combination of ground aluminum hydroxide and precipitated aluminum hydroxide. When used in polymer composites, APYRAL™ 20X has usable viscosity and thermal conductivity.

[0052] The "Bayer method" refers to the process of forming aluminum trioxide from bauxite and sodium hydroxide. This method involves dissolving bauxite in sodium hydroxide at a temperature of up to 270°C. The waste solids, known as bauxite tailings, are removed, and aluminum trioxide is precipitated from the remaining sodium aluminate solution.

[0053] Bauxite refers to rocks formed from reddish clay. Bauxite mainly consists of aluminum oxide, silicon oxide, iron oxide, and titanium oxide.

[0054] "BORATHERMTMSG-200LVS" refers to an ATH product manufactured by Sibelco™. BORATHERMTMSG-200LVS contains a mixture of two different types of milled ATH particles.

[0055] "D10" refers to the maximum particle size at 10% of the cumulative distribution of maximum particle size in a mixture of particles.

[0056] "D50" refers to the maximum particle size at 50% of the cumulative distribution of maximum particle sizes in a mixture of particles. D50 sometimes refers to the median maximum size in the particle size distribution.

[0057] "D97" refers to the maximum particle size at 97% of the cumulative distribution of maximum particle size in a mixture of particles.

[0058] "Flame retardancy" refers to the ability of a component to prevent ignition or to slow the spread of fire.

[0059] "Grinded aluminum hydroxide" refers to aluminum hydroxide powder obtained from bauxite tailings sedimentation and subsequent grinding and / or sieving operations. Grinded aluminum hydroxide is typically formed by grinding particles to a maximum size of less than 300 µm. Grinding mills include jet mills, ball mills, and roller mills.

[0060] "Maximum size" refers to the longest cross-sectional dimension of any particular particle. The aluminum hydroxide particles, a component of the present invention, can have various shapes, including but not limited to: general (though not perfect) spherical, elongated, cylindrical, conical, cubic, cuboid, tetrahedral, or irregular three-dimensional shapes.

[0061] "OCTEO" refers to the product currently sold by Evonik Operations GmbH. Dynasylan®OCTEO is a monomeric medium-chain N-octyltriethoxysilane. Dynasylan®OCTEO is a surface modifier used to create hydrophobicity on inorganic fillers to improve compatibility.

[0062] "Precipitated aluminum hydroxide" refers to ATH that has undergone two precipitation processes. First, it is precipitated from bauxite tailings; then, it is precipitated again to control particle size and morphology. Precipitated ATH is more difficult to form and more expensive than ground ATH.

[0063] “SEM” refers to a scanning electron microscope. A non-limiting example of a scanning electron microscope is the JEOLTM JSM-IT800.

[0064] Specific surface area refers to the area of ​​a solid surface per unit mass of material. Specific surface area can be measured by mercury porosimetry, optionally using a Pascal 100 Series (sold by Thermo Electron) and / or a Pascal 240 Series (sold by Thermo Electron).

[0065] "Total cumulative volume" refers to the total cumulative pore volume occupied by a substance (e.g., mercury) per unit mass as pressure increases. Total cumulative volume can be measured by mercury porosimetry, optionally using a Pascal 100 Series (sold by Thermo Electron) and / or a Pascal 240 Series (sold by Thermo Electron).

[0066] "Unavoidable impurities" refer to components that are present in the composition but do not affect the properties of the composition. The amount of unavoidable impurities present in the composition is: less than 5% by weight; or, less than 4% by weight; or, less than 3% by weight; or, less than 2% by weight; or, less than 1% by weight; or, less than 0.5% by weight; or, less than 0.1% by weight.

[0067] "Volume / Volume%" refers to the volume / volume ratio. For example, if the composition contains 40% or less volume / volume, then there are 40 mL or less of voids (or pores) per 100 mL of composition.

[0068] "Weight %" refers to the percentage by weight of a component in 100 grams of the composition. For example, if the composition contains 10% by weight of component A, then 10 grams of component A are present in every 100 grams of the composition.

[0069] The composition of this aluminum hydroxide (ATH) composition

[0070] In an example of this invention, the aluminum trioxide (ATH) composition is formed from milled ATH. The preparation of milled ATH is less complex than that of precipitated ATH. Previously, both milled ATH and precipitated ATH were used because precipitated ATH could be formed by controlling the morphology of the ATH particles. The inventors have surprisingly discovered that milled ATH (that is, ATH without any precipitated particles) can be used to manufacture advantageous ATH compositions.

[0071] In this embodiment of the invention, the ATH composition comprises a first (coarse) plurality of milled ATH particles and a second (fine) plurality of milled ATH particles.

[0072] Optionally, the first (coarse) plurality of milled ATH particles may contain a coating, the second (fine) plurality of milled ATH particles may contain a coating, or both the first (coarse) plurality of milled ATH particles and the second (fine) plurality of milled ATH particles may contain a coating. The coating may include one or more of the following: fatty acids and / or organosilanes. The coating may be included to provide favorable dispersibility, morphology, and / or interfacial compatibility.

[0073] In some embodiments of the present invention, the maximum size of the first (coarse) plurality of milled ATH particles is from 50 to 500 µm, from 50 to 300 µm, or from 75 to 200 µm, or from 100 to 150 µm (plus or minus 50 µm).

[0074] In some embodiments of the present invention, the maximum size of the second (fine-grained) plurality of milled ATH particles is less than 50 µm, or less than 40 µm, or less than 30 µm (plus or minus 5 µm). The maximum size of the second (fine-grained) plurality of milled ATH particles may be greater than 0.5 µm or greater than 1 µm.

[0075] In some embodiments of the present invention, the ATH composition contains a first (coarse-grained) plurality of milled ATH particles with a maximum size of 200µm (plus or minus 50µm) and a second (fine-grained) plurality of milled ATH particles with a maximum size of 30µm (plus or minus 5µm).

[0076] In some embodiments of the present invention, the first (coarse) plurality of milled ATH particles have the following characteristics: D10 is from 25 to 40 µm, or from 25 to 35 µm, or from 31 to 33 µm, or 32 µm; and D50 is from 90 to 110 µm, or from 100 to 104 µm, or 102 µm; and D97 is from 200 to 300 µm, or from 200 to 220 µm, or 210 µm.

[0077] In some embodiments of the present invention, the second (fine-grained) plurality of milled ATH particles have the following dimensions: D10 is from 1.0 to 4.0 µm, or from 1.0 to 2.0 µm, or 1.5 µm; and D50 is from 6 to 12 µm, or 8 µm; and D97 is from 25 to 40 µm, or from 30 to 34 µm, or 32 µm.

[0078] In some embodiments of the present invention, the D10 of the ATH composition is from 1 to 3 µm, or 2 µm; and, the D50 is from 20 to 24 µm, or 21.86 µm; and, the D97 is from 180 to 220 µm, or 198 µm.

[0079] In some embodiments of the present invention, the ATH composition comprises ATH particles with a maximum size distribution ranging from 0.1 to 305 µm.

[0080] In some embodiments of the present invention, the content of the first (coarse) plurality of milled ATH particles in the ATH composition is from 50 to 85% by weight, or from 60 to 85% by weight, or from 65 to 80% by weight, or from 70 to 75% by weight.

[0081] In some embodiments of the present invention, the content of the second (fine) plurality of milled ATH particles in the ATH composition is from 15 to 50% by weight, or from 15 to 40% by weight, or from 20 to 35% by weight, or from 25 to 30% by weight.

[0082] In some embodiments of the present invention, the ratio (by weight) of the first (coarse) plurality of ground ATH particles to the second (fine) plurality of ground ATH particles in the ATH composition is: 12.5 (coarse): 3.5 (fine), or 8 (coarse): 1.5 (fine), or 10 (coarse): 5 (fine), or 4 (coarse): 2.2 (fine), each plus or minus 0.5.

[0083] In some embodiments of the present invention, the ratio of the first (coarse) plurality of ground ATH particles to the second (fine) plurality of ground ATH particles results in a void (or pore) volume / volume % of the ATH composition being 40 or lower; or, the void (or pore) volume / volume % of the ATH composition being 34 or lower.

[0084] Advantageously, the ATH composition of the present invention has the same or similar physical properties as known ATH compositions.

[0085] In some embodiments of the invention, when in a polymer matrix, the ATH composition advantageously possesses beneficial thermal conductivity compared to known ATH compositions. Preferably, the thermal conductivity of the ATH composition (in a polymer matrix having a linear non-reactive polydimethylsiloxane; the ATH composition loading in the polymer is 87.5 wt% ATH composition and 12.5 wt% polymer) is from 2.6 to 2.9 W / mK (or 2.8 to 2.9 W / mK). Advantageously, the improved thermal conductivity contributes to the rheological and thermal properties of the ATH composition (i.e., improved heat dissipation). For example, the more favorable thermal conductivity allows the ATH composition to conduct more heat energy and thus serves as an advantageous flame retardant or heat inhibitor.

[0086] In some embodiments of the present invention, when in a polymer matrix, the ATH composition advantageously possesses a beneficial viscosity compared to known ATH compositions. Optionally, the viscosity of the ATH composition is 13 Pa·s or less, or 11 Pa·s or less, or 9 Pa·s or less, or from 8 to 9 Pa·s. Advantageously, the improved viscosity results in better flowability of the ATH composition of the present invention, such as self-homogenizing behavior.

[0087] In some embodiments of the present invention, the ATH composition has a beneficial density of 2.42 g / cm3 (plus or minus 0.2 g / cm3).

[0088] Formation of aluminum trioxide composition (ATH composition)

[0089] In some instances of this invention, ATH is derived from bauxite that has undergone the Bayer process.

[0090] This ATH composition is formed from different ground ATH particles.

[0091] The ATH composition comprises a first (coarse) plurality of ground ATH particles and a second (fine) plurality of ground ATH particles. Prior to mixing, the first (coarse) plurality of ground ATH particles and the second (fine) plurality of ground ATH particles are sieved separately (to the desired size) to remove any unwanted impurities. The first (coarse) plurality of ground ATH particles and the second (fine) plurality of ground ATH particles are then mixed.

[0092] The mixing of the first (coarse) plurality of ground ATH particles and the second (fine) plurality of ground ATH particles is performed as follows: from 0.1 to 8 hours at 25°C; from 0.3 to 4 hours at 25°C; from 0.5 to 2 hours at 25°C; or, until a mixture with uniform particle distribution is formed at 25°C.

[0093] The ratio of the first (coarse) plurality of ground ATH particles to the second (fine) plurality of ground ATH particles in the mixture is: 12.5 (fine): 3.5 (coarse); or 8 (coarse): 1.5 (fine); or 10 (fine): 5 (coarse); or 4 (coarse): 2.2 (fine).

[0094] This mixing step uses any known mixing method. For example, mixing can be performed using low-shear mixing in a horizontal axis mixer. In some cases, mixing occurs in a horizontal ribbon mixer sold by Gebrüder Lödige Maschinenbau GmbH.

[0095] The resulting mixture contains both the first (coarse) plurality of ground ATH particles and the second (fine) plurality of ground ATH particles with a uniform particle distribution. This uniform particle distribution ensures thorough mixing of ATH particles of all sizes.

[0096] Advantageously, the mixing results in an ATH composition composed of particles with a broad particle size distribution ranging from 0.1 to 500 μm. This is attributed to the fragility of the second (fine-grained) plurality of milled ATH particles, so that during the mixing step, the first (coarse-grained) plurality of milled ATH particles assist in the de-aggregation of the second (fine-grained) plurality of milled ATH particles. It is not intended to be theoretically limited, but it is believed that including the first (coarse-grained) plurality of milled ATH particles and the second (fine-grained) plurality of milled ATH particles results in a beneficial packaging of different particle sizes, leading to beneficial viscosity, density, and thermal conductivity.

[0097] Advantageously, this mixing action yields a dense ATH composition with a void (or pore) volume percentage of 40 or less; or, a void (or pore) volume percentage of 34 or less. Therefore, this ATH composition is capable of forming a high filler loading within a polymer matrix.

[0098] Advantageously, this mixing action results in an ATH composition with a viscosity of 13 Pa·s or less in a specified polymer matrix; or, 11 Pa·s or less; or, 9 Pa·s or less. The resulting ATH composition is free-flowing.

[0099] Example

[0100] The following are non-limiting examples, in which the advantages of the invention are discussed with reference to the accompanying tables and figures. The examples listed herein are non-limiting and are merely examples among other possible examples.

[0101] Example 1: Comparison of starting materials

[0102] The following non-limiting examples compare the morphology of the first (coarse-grained) plurality of milled ATH particles and the second (fine-grained) plurality of milled ATH particles included in the ATH composition of the present invention.

[0103] Figure 1 is an SEM image showing the morphology of a first (coarse-grained) plurality of ground ATH particles in a non-limiting example. As shown in Figure 1, the morphology of the first (coarse-grained) plurality of ground ATH particles is dense, compact, and has few pores on the surface.

[0104] Figure 2 is an SEM image showing the morphology of a second (fine-grained) plurality of ground ATH particles in a non-limiting example. As shown in Figure 2, the morphology of the second (fine-grained) plurality of ground ATH particles is a small-sized aggregate containing particles.

[0105] Comparing Figures 1 and 2, it was observed that the morphology of the first (coarse-grained) plurality of ground ATH particles was significantly denser and / or more uniform than that of the second (fine-grained) plurality of ground ATH particles.

[0106] Advantageously, by forming an ATH composition from the first (coarse) plurality of milled ATH particles and the second (fine) plurality of milled ATH particles, the volume / volume % of the voids (or pores) in the formed ATH composition of the aluminum hydroxide is 40 or lower.

[0107] Example 2: Comparison of coarse-grained materials

[0108] The following non-limiting examples compare the morphologies of two coarse-grained materials (coarse-grained A and coarse-grained B) that may be included in the ATH compositions of the present invention. The first coarse-grained material (coarse-grained A) is included in the compositions ATHE1, ATHE2 and ATHE3, while the second coarse-grained material (coarse-grained B) is included in the composition BORATHERMTMSG-200LVS.

[0109] Figure 3 shows the pore size distribution of the first (coarse) plurality of ground ATH particles (the first (coarse) plurality of ground ATH particles contained in the ATHE1, ATHE2 and ATHE3 compositions; coarse particles A).

[0110] Figure 4 shows the pore size distribution of the first (coarse) plurality of ground ATH particles (the first (coarse) plurality of ground ATH particles contained in the BORATHERMTMSG-200LVS composition; coarse particles B).

[0111] As shown in Figures 3 and 4, the pore size distribution of coarse particles B is larger than that of coarse particles A. The pore size distributions in Figures 3 and 4 were obtained using mercury porosimetry with Pascal 100 Series and Pascal 240 Series (sold by Thermo Electron).

[0112] Advantageously, the ATH composition produced can be formed from an aluminum hydroxide composition with a volume / volume % of pores (or voids) of 40 or less by forming an ATH composition containing coarse-grained A.

[0113] Figure 5 is a SEM image showing the morphology of coarse-grained A.

[0114] Figure 6 is a SEM image showing the morphology of coarse-grained B.

[0115] Advantageously, coarse particles A (composed of larger particles compared to coarse particles B) exhibit a less dense and less uniform morphology, composed of both small and large particles. Furthermore, coarse particles B exhibit a morphology characterized by more edge damage, creating more porosity and a higher surface area. Not wishing to be limited by theory, it is believed that the aluminum hydroxide composition comprises a first (coarse-grained) plurality of milled aluminum hydroxide particles with a total cumulative volume of 76 mm³ / g or less, and the provided ATH composition is an aluminum hydroxide composition with a pore (or void) volume / volume % of 40 or less. Furthermore, not wishing to be limited by theory, it is believed that the aluminum hydroxide composition comprises a first (coarse-grained) plurality of milled aluminum hydroxide particles with a specific surface area of ​​3 m² / g or less, and the provided ATH composition is an aluminum hydroxide composition with a pore (or void) volume / volume % of 40 or less.

[0116] Advantageously, by forming an ATH composition comprising the first (coarse) plurality of coarse particles A, and a polymer composite comprising these ATH compositions, a relatively high thermal conductivity value can be obtained.

[0117] Example 3: Maximum particle size distribution in this ATH composition

[0118] The following non-limiting examples compare the maximum particle size distribution in the ATH composition of the present invention.

[0119] Figure 7 shows the maximum size distribution of particles in the example ATH composition (referred to as ATHE2), expressed as a cumulative distribution function summing to 100. In ATHE2, the ratio of the first (coarse) plurality of milled ATH particles to the second (fine) plurality of milled ATH particles is (in weight %): 70 (coarse): 30 (fine). Figure 8 shows the maximum size distribution of particles in ATHE2 as a function of relative distribution. The maximum size distributions in Figures 7 and 8 were measured using a HELOS laser diffraction instrument (sold by Sympatec GmbH).

[0120] Each sample was dispersed in water (using stirring and ultrasonic treatment), and the maximum particle size distribution was measured using laser diffraction. Measurements were taken using a HELOS laser diffraction instrument (sold by Sympatec GmbH). Mie's scattering theory was applied to the scattering data to determine the maximum particle size in ATHE2.

[0121] As shown in Figures 7 and 8, a unique maximum size distribution was obtained, in which the particles in ATHE2 have a maximum size distribution ranging from 0.1 to 305 µm. This result can be attributed to the disintegration of the first (coarse) plurality of milled ATH particles and the deaggregation of the second (fine) plurality of milled ATH particles during the mixing step.

[0122] Example 4: Analysis of the effect of the ratio of the first (coarse) plurality of ground ATH particles to the second (fine) plurality of ground ATH particles on the physical properties of the ATH composition. []

[0123] The following non-limiting example analysis stems from the change in physical properties caused by the change in the ratio of the first (coarse) plurality of ground ATH particles to the second (fine) plurality of ground ATH particles.

[0124] Three different ATH compositions were prepared. The ratio of the first (coarse) plurality of milled ATH particles to the second (fine) plurality of milled ATH particles in each composition was (in weight %): 60 (coarse): 40 (fine) (ATHE1); 70 (coarse): 30 (fine) (ATHE2); and 80 (coarse): 20 (fine) (ATHE3).

[0125] The known components of ATH are APYRALTM20X and BORATHERMTMSG-200LVS.

[0126] This invention involves the individual addition of three different ATH components (ATHE1, ATHE2, and ATHE3) and the known ATH components APYRALTM20X and BORATHERMTMSG-200LVS to a silicate to form a complex (each separately). The complex comprises 70% by weight of each of the ATH components, with the remainder being a silicate. The silicate used is polydimethylsiloxane, with a viscosity of approximately 500 mm² / s at 30°C and a shear rate of 10 m / s. Before viscosity measurement, the ATH components are thoroughly dispersed in the silicate matrix by high-speed double asymmetric centrifugation at 3000 rpm for 1 minute, followed by deposition in an oven at 30°C for 10 minutes. Before viscosity measurement, any accumulated structures are removed by manual stirring with a spatula.

[0127] The viscosity of each solution (siloxane and ATH composition) was measured using a Brookfield cone / plate viscometer with an NR-52 rotating shaft.

[0128] Figure 9 illustrates the viscosity of three different ATH compositions (ATHE1, ATHE2, and ATHE3) of the present invention and the known ATH composition, APYRALTM20X, in the siloxane. As shown in Figure 9, the viscosity of the ATH compositions of the present invention at ratios of 70:30 (ATHE2) and 80:20 (ATHE3) is lower than that of the known ATH composition APYRALTM20X. Advantageously, with respect to the ATH compositions of the present invention (in siloxane media), the lower viscosity results in better flowability, such as self-homogenizing behavior.

[0129] Tables 2A and 2B compare the density and heat capacity of the three example ATH compositions of the present invention (ATHE1, ATHE2, and ATHE3) with those of the known ATH compositions APYRALTM20X and BORATHERMTMSG-200LVS.

[0130] As shown in Tables 2A and 2B, when in complexes with silicone polymers, the ATH composition of the present invention has similar density and heat capacity to the known ATH composition.

[0131] Example 5: Comparison of the thermal conductivity of the ATH composition of the present invention with known ATH compositions.

[0132] The following non-limiting examples compare the thermal conductivity of the ATH composition of the present invention with that of known ATH compositions.

[0133] Three different ATH compositions were prepared. The ratio (in weight %) of the first (coarse) plurality of milled ATH particles to the second (fine) plurality of milled ATH particles in each composition were 60:40 (ATHE1); 70:30 (ATHE2); and 80:20 (ATHE3).

[0134] The known ATH components used are APYRALTM20X and BORATHERMTMSG-200LVS.

[0135] Three different ATH components (ATHE1, ATHE2, and ATHE3) of the present invention, along with known ATH components, were added to a silicate to form a complex. The complex comprised 87.5% by weight of each of the ATH components, with the remainder being silicate. Prior to thermal conductivity measurements, the ATH components were thoroughly dispersed in the silicate matrix by high-speed double asymmetric centrifugation at 3000 rpm for 1 minute, and then cooled before measurement.

[0136] The thermal effusivity of each composite was measured using a modified transient planar source conductor (sold by C-Therm Technologies Ltd.) connected to a Trident™ thermal conductivity meter. These thermal effusivity values, along with density and heat capacity, were then used to obtain the thermal conductivity of the composite. The thermal effusivity values ​​are listed in Table 1. The thermal conductivity of each composite was calculated using the following equation: Where e is the thermal ejection rate of the composite, λ is the thermal conductivity of the composite, ρ is the density of the composite, and Cp is the specific heat capacity of the composite at a specified temperature.

[0137] Table 3 lists the thermal conductivity of the ATH composition of the present invention in the siloxane matrix (i.e., in the complex with the siloxane polymer) and the known ATH compositions APYRALTM20X and BORATHERMTMSG-200LVS.

[0138] The ATH composition of this invention has an improved (higher) thermal conductivity value, which advantageously contributes to the rheological and thermal properties of the ATH composition. Higher thermal conductivity of the example ATH composition means that the filler content in the polymer matrix can be kept to a minimum, resulting in a lower density of the polymer composite.

[0139] Example 6: Comparison of the maximum particle size distribution of the ATH composition of the present invention with that of known ATH compositions. []

[0140] The following non-restrictive examples compare the particle maximum size distribution of components in the example ATH composition with those in known ATH compositions.

[0141] The known ATH component is BORATHERMTMSG-200LVS.

[0142] Each sample was dispersed in water (using stirring and ultrasonic treatment), and the maximum size distribution of ATH particles was measured using laser diffraction. Measurements were taken using a HELOS laser diffraction instrument (sold by Sympatec GmbH). Mie's scattering theory was applied to the scattering data to determine the maximum particle size of the components in ATHE1, ATHE2, and ATHE3.

[0143] The maximum particle size distribution is shown in Table 4.

[0144] As shown in Table 4, the components of the ATH composition of the present invention have different maximum particle size distributions. This different maximum particle size distribution provides an advantageous filling of ATH particles in the ATH composition of the present invention.

[0145] Example 7: Comparison of the thermal conductivity of the ATH composition of the present invention and known ATH compositions in a thermoplastic polymer matrix. []

[0146] The following non-limiting examples compare the thermal conductivity changes of the 70:30 (ATHE2) ATH composition of the present invention and the known ATH composition APYRALTM20X after mixing in different polymer matrices. Each sample was coated with 1% OCTEO. Then, each sample was added to a polyethylene wax (PE wax) matrix to form a composite. The composite contained 87.5% by weight of various ATH compositions.

[0147] Before thermal conductivity measurements, each ATH component was fully dispersed in polyethylene wax. For the polyethylene composite, the ATH component was dispersed in the molten polymer. The mixture was then fully dispersed by high-speed double asymmetric centrifugation at 3000 rpm for 1 minute. Both systems were then cooled before the measurement.

[0148] The thermal ejection rate of the compound was measured using the same method as in Example 5.

[0149] Table 5 compares the density and heat capacity of the ATH composition 70:30 (ATHE2) of the present invention and the known ATH composition APYRALTM20X in polyethylene wax.

[0150] As shown in Table 5, when in a compound with polyethylene wax, the ATH composition of the present invention has a slightly lower density and a slightly higher heat capacity compared to known ATH compositions.

[0151] Table 6 shows the thermal conductivity of the ATH composition 70:30 (ATHE2) of the present invention and the known ATH composition APYRALTM20X in the polyethylene wax.

[0152] When blended with polyethylene wax, the ATH composition 70:30 (ATHE2) and APYRALTM20X of this invention exhibit relatively high thermal conductivity.

[0153] When used in this specification and the claims, the terms "comprising" and "including," and variations thereof, mean to include the specified feature, step, or whole. This use of the terms is not intended to exclude the presence of other features, steps, or components.

[0154] The features disclosed in the preceding description, or in the subsequent claims, or in the accompanying drawings, either in their particular form or in the manner of implementing the disclosed function, or in the method or procedure for achieving the disclosed result, may suitably be used, individually or in any combination of these features, to implement the invention in various forms.

Claims

1. An aluminum hydroxide composition comprising (or composed of): 50% to 85% by weight of a first plurality of milled aluminum hydroxide particles having a maximum size of 50 to 500 µm; 15% to 50% by weight of a second plurality of milled aluminum hydroxide particles having a maximum size of less than 50 µm, wherein the first plurality of milled ATH particles have: a D10 of 25 to 40 µm, a D50 of 90 to 110 µm; and a D97 of 200 to 300 µm; wherein the second plurality of milled ATH particles have: a D10 of 1.0 to 4.0 µm, a D50 of 6 to 12 µm; and a D97 of 25 to 40 µm.

2. The aluminum hydroxide composition of claim 1, wherein the first plurality of milled ATH particles have: D10 of 25 to 35 µm, D50 of 100 to 104 µm; and D97 of 200 to 220 µm.

3. The aluminum hydroxide composition of claim 1, wherein the second plurality of milled ATH particles have: D10 of 1.0 to 2.0 µm, D50 of 8 µm; and D97 of 30 to 34 µm.

4. The aluminum hydroxide composition of claim 1, wherein the aluminum hydroxide composition has: D10 from 1 to 3 µm, D50 from 20 to 24 µm; and D97 from 180 to 220 µm.

5. The aluminum hydroxide composition of claim 1, wherein the total cumulative volume of the first plurality of milled aluminum hydroxide particles is 76 mm³ / g or less.

6. The aluminum hydroxide composition of claim 1, wherein the specific surface area of ​​the first plurality of milled aluminum hydroxide particles is 3 m² / g or less.

7. The aluminum hydroxide composition of claim 1, wherein the aluminum hydroxide composition comprises the first plurality of milled aluminum hydroxide particles in an amount of 60 to 85 by weight.

8. The aluminum hydroxide composition of claim 1, wherein the aluminum hydroxide composition comprises the second plurality of milled ATH particles in an amount of 15 to 40 by weight.

9. The aluminum hydroxide composition of claim 1, wherein: the first plurality of milled aluminum hydroxide particles have a maximum size of 300 µm; and the second plurality of milled aluminum hydroxide particles have a maximum size of 30 µm.

10. The aluminum hydroxide composition of claim 1, wherein the ratio of the first plurality of aluminum hydroxide particles to the second plurality of aluminum hydroxide particles in the aluminum hydroxide composition is (in weight %): 12.5 (first): 3.5 (second).

11. The aluminum hydroxide composition of claim 1, wherein the ratio of the first plurality of milled aluminum hydroxide particles to the second plurality of milled aluminum hydroxide particles results in the aluminum hydroxide composition having 40 volume / volume% or less of voids (or pores).

12. The aluminum hydroxide composition of claim 1, wherein the density of the aluminum hydroxide composition is 2.42 g / cm3.

13. The aluminum hydroxide composition of claim 1, wherein the first plurality of milled ATH particles and the second plurality of milled ATH particles of the aluminum hydroxide composition have a uniform particle distribution.

14. The aluminum hydroxide composition of claim 1, wherein the maximum particle size distribution in the aluminum hydroxide composition is from 0.1 to 305 µm.

15. A method for manufacturing an aluminum hydroxide composition, the method comprising the steps of: providing a first plurality of milled aluminum hydroxide particles having a maximum size of 50 to 500 µm in 50% to 85% by weight; And, provide a second plurality of milled aluminum hydroxide particles, the maximum size of which is less than 50 µm in 15 wt% to 50 wt%; And, the first plurality of ground aluminum hydroxide particles and the second plurality of ground aluminum hydroxide particles are mixed, wherein the aluminum hydroxide composition, the first plurality of ground aluminum hydroxide particles and / or the second plurality of ground aluminum hydroxide particles are any one of claims 1 to 14.

16. The method of claim 15, wherein the mixing step is performed at 25°C for 0.1 to 8 hours.

17. The method of claim 15, wherein the ratio of the first plurality of ground aluminum hydroxide particles to the second plurality of ground aluminum hydroxide particles in the mixture is (in weight %): 12.5 (first): 3.5 (second).

18. The aluminum hydroxide composition as requested in claim 1, which is used as a flame retardant and / or as a thermal management filler.

19. A polymer complex comprising a polymer and an aluminum hydroxide composition as claimed in any one of claims 1 to 14.

20. The polymer composite of claim 19, wherein the polymer is a polymer formed from polysiloxane, epoxide, polyester, polyethylene wax and / or polyol.

21. The polymer complex of claim 19 or 20, wherein the polymer complex comprises (in weight percent): 50 to 90 weight percent of an aluminum trioxide composition of any one of claims 1 to 14; and 10 to 50 weight percent of a polymer.

22. The polymer composite of claim 19 or 20, wherein the thermal conductivity of the polymer composite is from 2 to 7 W / mK.

23. The polymer composite of claim 19 or 20, wherein the viscosity of the polymer composite is 13 Pa·s or less.

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