BACKGROUND [0001] For many flame retardant applications use of a particulate phosphorus flame retardant is desired. For example, while such liquid flame retardants might be of interest in production of flame retarded wire and cable products, such liquid products are difficult to handle and dose due to high volatility leading to evaporation or due to high viscosity causing problems with flow. Indeed, many polymer producers are equipped for, and accustomed to, using flame retardants in particulate form such as powders and granules.

[0002] While these shortcomings of liquid flame retardants may be circumvented by forming a masterbatch of the liquid phosphorus flame retardant in the polymer to be flame retarded, this necessitates subjecting the flame retardant to a temperature high enough to melt the polymer during the time the flame retardant is being blended with the polymer in forming the masterbatch. Such exposure to an extra heating step at high temperature is not desirable.

[0003] Additionally, handling of relatively volatile liquid phosphorus flame retardants and very viscous liquid phosphorus flame retardants such as in wire and cable applications and in the production of thermoset resins is difficult due to risk of losing material or imprecise dosing.

[0004] It would be very desirable if an economic ally- attractive way could be found of providing normally liquid phosphorus flame retardants in a less volatile, non-sticky dry form, especially if this could be accomplished without need for exposing the flame retardant to an extra heating step at high polymer melting temperature.

BRIEF NON-LIMITING SUMMARY OF THE INVENTION

[0005] This invention provides an effective way of providing normally liquid phosphorus flame retardants in a less volatile, non-sticky dry form, without exposing the flame retardant to an extra heating step at high polymer melting temperature. In addition, the particulate forms of the invention are in the form of powders which have excellent flowability properties and are thus readily handled in various types of commercially- available loading and blending equipment. Moreover, these desirable achievements can be accomplished in an economically-attractive manner. [0006] This invention thus provides, among other things, a flame retardant composition comprising at least one phosphorus-containing flame retardant that has been absorbed when in the liquid state by (i) a transition alumina, (ii) a boehmite, (iii) a pseudo boehmite, or (iv) a combination of any two or all three of (i), (ii), and (iii), which composition is in the form of a free-flowing powder. Surprisingly, a number of such compositions, if not all such compositions, have a greater flowability in the Vibrating Funnel Test (described hereinafter) than a separate untreated portion of the same transition alumina, boehmite, and/or pseudo boehmite used in forming the flame retardant in the form of a free-flowing powder. This was found to be the case even where the separate untreated portion of the flame retardant was a solid at room temperature and thus was heated to a temperature of about 100 ⁰ C in order to convert it into a liquid used in forming an absorbed flame retardant composition of this invention.

[0007] Also provided by this invention are particulate flame retardant compositions comprising a mixture of (A) a flame retardant composition in the form of a free-flowing powder as described above and (B) a particulate inorganic flame retardant selected from (a) aluminum trihydrate, (b) magnesium hydroxide, or (c) both of (a) and (b). Still further compositions of this invention are each of those described hereinabove which further comprise high bulk density, high flow particulate silica comprised of finely-divided spherical particles. These compositions have been shown to still further improve flowability characteristics of at least some of the particulate flame retardant compositions of this invention.

[0008] Methods of preparing a particulate flame retardant composition from at least one liquid phosphorus flame retardant are also provided by this invention. One such method comprises adding at least one phosphorus flame retardant in the liquid state portionwise to a finely-divided (i) transition alumina, (ii) boehmite, (iii) pseudo boehmite, or (iv) any two or all three of (i), (ii), and (iii). Alternatively, the liquid phosphorus flame retardant(s) and the finely-divided (i) transition alumina, (ii) boehmite, (iii) pseudo boehmite, or (iv) any two or all three of (i), (ii), and (iii) can be separately and concurrently introduced into the mixing vessel. [0009] Yet another aspect of this invention is a flame retarded composition which comprises at least one thermoplastic polymer, thermoset polymer, or elastomer (i.e., natural or synthetic rubber) with which has been blended a flame retardant composition of this invention in the form of a free-flowing powder. The amount of the flame retardant of this invention used in forming such flame retarded compositions is an amount at least sufficient to flame retard the at least one polymer or elastomer with which the free-flowing flame retardant composition of this invention is blended. Such amounts may range from about 5 to about 95 wt%, depending upon the type of composition being formed (e.g., finished polymer or masterbatch blend).

[0010] These and other embodiments, features, and advantages of this invention will become still further apparent from the ensuing description and appended claims.

FURTHER DETAILED DESCRIPTION OF EMBODIMENTS OF THIS INVENTION

Glossary

[0011] As used herein, including the claims, the term "powder" means that the specified substance is in the form of separate particles which can be in the form of a powder or small grains of a size up to about the size of smelter grade alumina that has a median particle size of about 100 μm. The exact size and spatial configuration of the particles is not critical, as long as the particles are freely flowable if subjected to the Vibrating Funnel Test (described hereinafter). Thus, the "powder" is a powder or small grains with a median particle size of about 100 μm which is in a flowable form in the Vibrating Funnel Test. [0012] As used herein, including the claims, the term "phosphorus-containing flame retardant" refers to organic phosphorus compounds that are in the liquid state at room temperature or that are in the solids state at room temperature but which can be converted into liquid form at an elevated temperature of up to about HO ⁰ C. [0013] As used herein, the term "carrier" refers to (i) a transition alumina, (ii) a boehmite, (iii) a pseudo boehmite, or (iv) a combination of any two or all three of (i), (ii), and (iii) in the form of a powder and having the ability to absorb at least one phosphorus flame retardant when the latter is in the liquid state.

[0014] As used herein, the terms "powdery blend" or "powdery blend of this invention", whether in the singular or plural, refer to a carrier which has absorbed a phosphorus flame retardant when the latter is in its liquid state, and which carrier plus absorbed phosphorus flame retardant appears and behaves as if it is dry.

[0015] As used herein, including the claims, the term "absorbed" means that the liquid phosphorus flame retardant is taken up into the body of the carrier and thus forms an apparently dry blend, i.e., a powder which appears and behaves as if it is dry. The free- flowing flame retardant powdery blends of this invention as formed may involve any of a number of different mechanisms such as absorption within spatial openings or pores within the boehmite, and/or surface absorption, infusion, permeation or other types of interactions between the liquid phosphorus flame retardant and the particles of the carrier. This invention is not intended to be limited to any particular mechanism by which the liquid phosphorus flame retardant becomes taken up by the carrier.

Carriers

[0016] The powdery carriers used in the practice of this invention will typically have a suitable volume of pores in their powdery particles. Typically, the specific pore volume of the carriers is at least about 500 mm ³ /g, and preferably at least about 700 mm ³ /g, as measured by mercury intrusion porosimetry. Details of such a procedure are set forth hereinafter under the heading "Test Methods". [0017] One preferred type of carrier used in forming the powdery blends of this invention is a transition alumina. Transition aluminas are dehydroxylation products formed when, for example, aluminum hydroxide or boehmite is thermally treated below 1000 ⁰ C. The structure depends on the starting material as well as on the temperature of the treatment. Transition aluminas (chi, eta, rho, gamma, kappa, delta and theta alumina) will be converted into alpha alumina once heated to or calcined at a temperature of at least about HOO ⁰ C. Methods for the preparation of transition aluminas are known and reported in the literature. See in this connection, Materials Research, 2000, Vol.3, No.4, 104-114, the full disclosure of which is incorporated herein by reference, which gives a good overview of transition aluminas and their preparation. [0018] Transition aluminas are available as articles of commerce. Non-limiting examples include: MARTOXID AN/I and MARTOXID AN/I-406 (gamma alumina) from Martinswerk GmbH.

[0019] Unless it has been established that the transition alumina to be used is essentially devoid of water, it is desirable to heat treat the transition alumina to one or more temperatures in the range of about 300 to about 900 ⁰ C to drive off any moisture that may be present in the product.

[0020] Another type of carrier used in forming the powdery blends of this invention is boehmite. Boehmite in general has the chemical structure AlO(OH) and can be seen as an aluminium hydroxide with less water (about 17%) compared to aluminum trihydroxide Al(OH) ₃ (about 34.5%), which is often designated as ATH. Boehmite has a thermal stability higher than that of ATH and can be produced by a hydrothermal process. A precursor to make boehmite via the hydrothermal process can be Al(OH) ₃ . [0021] One commercially-available boehmite is Condea ^® P-200 (Condea Chemie GmbH). Boehmite can also exist in the form of quasi-crystalline boehmites. For details relating to the preparation of quasi-crystalline boehmites, one may refer to U.S. Pat. No. 6,689,333 Bl, the full disclosure of which is incorporated herein by reference. Some typical, commercially- available quasi-crystalline boehmites are available under the trademarks Pural ^® , (CONDEA CHEMIE GmbH), Catapal ^® (Sasol North America Inc.), and Versal ^® (UOP LLC).

[0022] Nanoboehmite is another material worthy of discussion as another type of carrier for use in the practice of this invention. Nanoboehmite can be considered as a subcategory of boehmites because the crystal size of nanoboehmite is in the nano meter range and its thermal stability and its X-ray diffraction (XRD) pattern have sharp peaks which clearly distinguish it from pseudoboehmite. Therefore, unless expressly indicated to the contrary, the term "boehmite" as used herein, including the claims, is to be understood to include nanoboehmite as a type of boehmite. Consequently, another preferred type of boehmite substrate which can be used in forming the particulate phosphorus flame retardants of this invention is a particulate nanoboehmite. Such boehmite particles are generally characterized by (i) having a BET specific surface area, as determined by DIN-66132, in the range of from about 20 to about 300 m ² /g; (ii) exhibiting a maximum loss on ignition (LOI) of about 20% at a temperature of 1200 ⁰ C; (iii) exhibiting a 2% weight loss at a temperature equal or higher than about 25O ⁰ C and a 5% weight loss at a temperature equal or higher than about 33O ⁰ C; (iv) being at least partly peptizable; (v) having a crystallite size between 10 and 25 nm; (vi) having an aspect ratio of less than about 2:1; or (vii) any combination of two or more of (i)-(vi), and preferably all of (i)-(vi).

[0023] Another type of carrier used in forming the powdery blends of this invention is a pseudoboehmite. Like boehmite, pseudoboehmite also has the formal structure AlO(OH) but contains more water than boehmite AlO(OH). Boehmite contains 17% bound water but pseudoboehmite can contain more that this. The thermal stability of pseudoboehmite is less as compared to boehmite. Boehmites are synthesized by processes at temperature close to 100 ⁰ C and ambient atmospheric pressures. Usually, pseudoboehmites have very high surface areas, large pores and pore volume and smaller crystal sizes than boehmites. The X-Ray diffraction pattern of pseudoboehmites show quite broad peaks and their half- widths are indicative of the crystal size as well as the degree of crystal perfection. The thermal stability of pseudoboehmite is less as compared to boehmite. Pseudoboehmite starts to release water below 200 ⁰ C while boehmite is stable up to at least 300 ⁰ C. While boehmite can be natural and synthetic, pseudoboehmite is not found in nature. Methods for the preparation of pseudoboehmites are known and reported in the literature. A discussion relating to the general topic of pseudoboehmites is provided in U.S. Pat. No. 6,689,333 Bl and International Publication Number WO 01/12553 Al, the full disclosures of which are incorporated herein by reference. [0024] Pseudoboehmites are not usually generally available as articles of commerce. They are mainly used as intermediates, for instance for the production of catalyst carriers. One such material is G45, manufactured by Albemarle Catalysts. It is an intermediate product that is not currently sold on the open market. [0025] As noted above, there are a number of carriers that can be used in the practice of this invention. These are in powder form. What constitutes a powder is a matter of common experience and common sense. The precise particle size of the powder is not critical to the practice of this invention. What is required is that the specified carriers be in finely-divided powdery form as distinguished from irregular granular form and that the powder have sufficient porosity to absorb the liquid phosphorus-containing flame retardant. Thus, in general, the carrier should have a minimum porosity of at least about 700 mm3/g. Typically, at least 90 wt% of the powder will have a particle size of no more than about 100 microns, and preferably no more than about 75 microns.

Phosphorus Flame Retardants [0026] In the practice of this invention, any phosphorus flame retardant that is in the form of a liquid at room temperature or that can be converted into a liquid state at a temperature of up to about HO ⁰ C and that can be absorbed by one of the above carriers, can be used pursuant to this invention. Thus, many different phosphorus flame retardants are available for use in the practice of this invention. For example, they can be one or more liquid polyphosphate esters that respond to the formula:

(RO) ₂ P(=O)O-[Ar-OP(=O)(OR)O] _n R where each R is, independently, an aryl or alkyl-substituted aryl group; Ar is an arylene group of 6 to 20 carbon atoms, and n is a number in the range of 1 to 8 with the proviso that if the polyphosphate ester is a mixture in which n is not the same for each component in the mixture, n is an average number which can be a fractional number within said range. The number or total number of carbon atoms in the alkyl portion(s) of the alkyl-substituted aryl group(s) can be any number of carbon atoms that results in the compound remaining as a liquid under the conditions specified in the present specification.

[0027] Preferred liquid polyphosphate esters are those in which R in the above formula is phenyl or alkyl-substituted phenyl, such as tolyl, xylyl, ethylphenyl, isopropylphenyl, and mesityl. The R groups may be the same or different, but preferably are at least isomers of the same group (e.g., various tolyl isomers or various xylyl isomers, etc.) if not all the same isomer. Most preferably R is a phenyl group. Typical arylene groups, Ar, are such groups as 1,3-phenylene, 1,4-phenylene, 4,4'-biphenylene (i.e., -C ₆ H ₄ -CeH ₄ -), methylenebis(4,4'-diphenylene) (i.e., -C ₆ H ₄ -CH ₂ -C ₆ H ₄ -), isopropylidenebis(4,4'- diphenylene) (i.e., -C ₆ H ₄ -CMe ₂ -C ₆ H ₄ -), sulfonebis(4,4'-diphenylene) (i.e., -C ₆ H ₄ -S(=O) ₂ - C ₆ H ₄ -), and similar divalent aromatic hydrocarbyl groups. A preferred polyphosphate ester is bisphenol-A bis(diphenylphosphate). Another preferred polyphosphate ester is resorcinolbis(diphenyl phosphate). These products can be the monomeric form of the specified polyphosphate ester (i.e., n in the above formula is 1), or (b) an oligomeric form of the specified polyphosphate ester which may or may not contain the monomeric form of the specified polyphosphate ester and which may be a single oligomer (i.e., n of the above formula is the same for each molecule in the product), but which more often is a mixture of oligomers (i.e., n of the above formula is not the same number for each molecule of the product). Therefore in case (b), n is an average value for the overall product and is greater than 1 but less than about 8. Often these products contain a small amount of triphenylphosphate which can be regarded as an impurity in which n of the above formula is, of course, zero. Such products are regarded in the art as being closely related compositions which have sufficient similarities to be identified by the same chemical name. For example, Akzo Nobel N. V. offers several polyphosphate ester products under the trademark Fyrolflex. One of these is Fyrolflex RDP with a stated phosphorus content of 10.9-11.0 wt%, and another is Fyrolflex RDP-B with a stated phosphorus content of 10.6 wt%. In addition, these products have different specified viscosities, and pour points. Yet both are identified as "resorcinolbis(diphenyl phosphate)". In other words the chemical name is the same, thus signifying a close relationship between or among the products. Similar considerations apply in or among such commercial products as Reophos RDP (Great Lakes Chemical Corporation) and CR733 (Daihatchi Chemical Industry Co. Ltd.); and in or among such products as Fyrolflex BDP (Akzo Nobel N.V.), Reophos BDP (Great Lakes Chemical Corporation), CR741 (Daihatchi Chemical Industry Co. Ltd.), and CR741S (Daihatchi Chemical Industry Co. Ltd.). [0028] One group of preferred compounds of the above formula are those in which n of the above formula is a number in the range of 1 to 2. Of these preferred compounds, those formed from bisphenol-A and in which R of the above formula is phenyl are particularly preferred. [0029] Another desirable type of liquid phosphorus flame retardants are chlorinated and/or brominated organic esters of an acid of phosphorus such as chlorinated and/or brominated phosphate and polyphosphate esters, chlorinated and/or brominated phosphonate or polyphosphonate esters, chlorinated and/or brominated phosphite esters, and the sulfur analogs of the foregoing such as chlorinated and/r brominated thiophosphates, thiophosphonates, and thiophosphites. Of these materials, liquid phosphorus flame retardants in which the molecule contains only carbon, hydrogen, oxygen, and at least one phosphorus atom are preferred. A number of suitable liquid phosphorus flame retardants are available as articles of commerce.

[0030] In cases where the phosphorus flame retardant is of sufficiently highly viscosity at room temperature to be taken up by the carrier, often the flame retardant can be, and preferably is, heated to a suitable modest temperature, e.g., from about 5O ⁰ C to about 11O ⁰ C to reduce its viscosity and thereby facilitate its take up by the carrier. Alternatively, it may be possible to utilize the highly viscous phosphorus flame retardant in the form of a solution to facilitate take up by the carrier. In this situation, the phosphorus flame retardant should be sufficiently soluble in a suitable organic solvent to provide a solution of high enough concentration (and low enough viscosity) to yield a powdery blend having a sufficient content of phosphorus to provide adequate flame retardancy. Generally speaking, the phosphorus content (calculated as phosphorus) of the powdery blends of this invention should be about 0.05 wt% or more, and preferably about 3 wt% or more, based on the total weight of the powdery blend of this invention. [0031] Among highly preferred commercially- available liquid phosphorus flame retardants for us in the practice of this invention are ANTIB LAZE ^® V490 flame retardant, ANTIBLAZE ^® V6 Flame Retardant, ANTIBLAZE ^® V66 Flame Retardant, ANTIBLAZE ^® TL-10-ST Flame Retardant, ANTIBLAZE ^® WR-30-LV Flame Retardant, and NCENDX ^® P30 flame retardant. The ANTIB LAZE ^® flame retardants are hydrocarbyl phosphonates and phosphates or partly chlorinated hydrocarbyl phosphonates and phosphates. All such flame retardants are available from Albemarle Corporation. Typical properties of these products are given below.

Flame Retardant Additive Compositions

[0032] Among the various flame retardant additive compositions of this invention are the following:

A) A flame retardant composition comprising at least one liquid phosphorus flame retardant absorbed by a carrier selected from (i) a transition alumina, (ii) a boehmite, (iii) a pseudoboehmite, or (iv) a combination of any two or all three of (i), (ii), and (iii), which composition is in the form of a free-flowing powder.

B) A flame retardant composition as in A) further characterized in that the flame retardant composition has a greater flowability in the Vibrating Funnel Test (described hereinafter) than a separate untreated portion of the same carrier used in forming that flame retardant composition.

C) A flame retardant composition comprising a mixture of (i) a flame retardant composition as in A) or B) and (ii) a particulate inorganic flame retardant selected from (a) aluminum trihydrate, (b) magnesium hydroxide, (c) boehmite or (d) any two or all three of (a), (b), and (c).

D) A flame retardant composition as in any of A), B), or C) which further comprises high bulk density, high flow particulate silica comprised of spherical particles.

[0033] The flame retardant compositions described in A) and B) above are effective flame retardants that require no additional flame retardant component. However, as seen from C) above, reference is made to aluminum trihydrate and magnesium hydroxide as components of those compositions. Aluminum trihydrate and magnesium hydroxide in powdery form or in the form of finely divided granules are themselves useful flame retardants and thus either or both of them can be effectively utilized in combination with the particulate flame retardant compositions of this invention. As indicated, the resultant mixed flame retardant compositions constitute additional compositions of this invention. The proportions of (i) a particulate flame retardant composition of this invention and (ii) aluminum trihydrate and/or magnesium hydroxide flame retardant(s) can be varied. Generally speaking, the weight ratio of (i):(ii) is typically in the range of 1:100 to 100:1, and preferably in the range of 1:10 to 10:1. Blending of these components to form these flame retardant mixtures can be accomplished using any conventional powder blending equipment.

[0034] In D) above, reference is made to high bulk density, high flow particulate silica comprised of spherical particles. Typically, such materials have a bulk density in the range of 100 kg/m ³ or even less. The high flow characteristics of these silicas manifest themselves in the ability of the silica to even further increase the flowability of the flame retardant compositions of A), B), and C) above in the Vibrating Funnel Test (described hereinafter). In addition, these silicas, when subjected in the absence of any other component to the Vibrating Funnel Test, pass the test very readily. Microscopic examination of the particles reveals their general spherical configuration in shape. Among suitable types of silicas that can be used in the practice of this invention are pyrogenic silicas, precipitated silicas, and micronized silicas. [0035] The phosphorus content (calculated as phosphorus) of the powdery blends of this invention should be at least about 0.05 wt% based on the total weight of the powdery blend. From a cost effectiveness standpoint, the amount of the liquid phosphorus flame retardant(s) present in the resultant powdery blend of this invention should be such that the powdery blend has a phosphorus content of at least about 0.05 wt%, and more preferably at least about 3 wt%. [0036] In the practice of the methods of this invention for preparing the powdery blends, contact is established between the liquid phosphorus flame retardant and the carrier, so that the flame retardant can be taken up by the substrate and thus form an apparently dry blend, i.e., a finely-divided product which appears and behaves as if it is dry. Although other ways of establishing such contact may be used, for best results at least one phosphorus flame retardant in the liquid state is added portionwise to a carrier or mixture of carriers. Alternatively, the phosphorus flame retardant(s) and the carrier(s) can be separately and concurrently introduced into the mixing vessel. During the contacting, the components should be thoroughly mixed during such addition to ensure substantially uniform dispersal of the carrier(s) and the liquid phosphorus flame retardant(s). [0037] The particulate flame retardant compositions of this invention are free flowing compositions that can be readily handled in hoppers and other material transfer equipment. Nevertheless, in some instances the flowability characteristics of the particulate flame retardant compositions can be further enhanced by including therewith a particulate inorganic flame retardant selected from (a) aluminum trihydrate, (b) magnesium hydroxide, and (c) mixtures of (a) and (b). Flame Retarded Polymer Compositions

[0038] This invention further includes the provision of flame retarded polymer compositions, in which the polymer can be a thermoplastic polymer, a thermoset polymer, or an elastomer (e.g., natural and synthetic rubbers and blends thereof). Non-limiting examples of thermoplastic polymers (including resins) in which the flame retardant additive compositions of this invention find use include polyethylene, polypropylene, ethylene-propylene copolymer, polymers and copolymers of C ₂ to Cg olefins (α-olefin) such as polybutene, poly(4-methylpentene-l) or the like, copolymers of these olefins and diene, ethylene- acrylate copolymer, polystyrene, ABS resin, AAS resin, AS resin, MBS resin, ethylene-vinyl chloride copolymer resin, ethylene-vinyl acetate copolymer resin, ethylene-vinyl chloride-vinyl acetate graft polymer resin, vinylidene chloride, polyvinyl chloride, chlorinated polyethylene, chlorinated polypropylene, vinyl chloride-propylene copolymer, vinyl acetate resin, phenoxy resin, polyacetal, polyamide, polyimide, polycarbonate, polysulfone, polyphenylene oxide, polyphenylene sulfide, polyethylene terephthalate, polybutylene terephthalate, methacrylic resin and the like. Further examples of suitable synthetic resins include natural or synthetic rubbers such as EPDM, butyl rubber, isoprene rubber, SBR, NIR, urethane rubber, polybutadiene rubber, acrylic rubber, silicone rubber, fluoro-elastomer, NBR and chloro- sulfonated polyethylene are also included. Further included are polymeric suspensions (latices). [0039] Preferred uses of the flame retardants of this invention are as components of polyethylene and its copolymers or polypropylene and its copolymers for wire and cable applications or resins such as epoxy resins for printed circuit boards and unsaturated polyesters. [0040] The various flame retardant additive compositions of this invention are blended with the appropriate substrate polymer(s) or elastomer(s) in an amount that is at least sufficient to provide flame retardancy to the resultant composition. Generally speaking, the amount of any given flame retardant in the form of a flame retardant additive composition of this invention will typically fall in the range of about 10 to about 90 wt%, and preferably in the range of about 50 to about 85 wt%, based on the total weight of the resultant flame retarded polymer or elastomer composition. In this connection, in forming such blends of substrate polymer or elastomer and flame retarded additive composition of this invention in which more than one additive component is used, (e.g., a combination of a powdery blend and aluminum trihydrate, or magnesium hydroxide, with or without other additives) the individual components can be blended separately or in various subcombinations, or both. However, generally speaking, it is desirable to utilize a preformed blend of the powdery blend and other components to be used therewith as this simplifies the blending operation and minimizes the likelihood of blending errors. [0041] The flame retardant additive compositions of this invention (i.e., the flame retardant additive composition comprising at least one liquid phosphorus flame retardant absorbed by (i) a transition alumina, (ii) a boehmite, (iii) a pseudo boehmite, or (iv) a combination of any two or all three of (i), (ii), and (iii), which composition is in the form of a free-flowing powder) can be formed by any conventional blending procedure.

Other Additive Components

[0042] Any of a wide variety of other common polymer additives can be used either as (1) components of flame retardant additive powders of this invention comprised of a powdery blend and at least one flame retardant additive powder physically admixed or blended therewith or (2) components that are separately blended as a powdery blend and at least one other flame retardant additive powder into the polymer being molded along with a flame retardant additive composition of this invention. Non-limiting examples of the types of additives that can be utilized in this manner include extrusion aids, fatty acids; coupling agents such as amino-, vinyl- or alkyl silanes or maleic acid grafted polymers; sodium stearate or calcium stearate; organoperoxides; dyes; pigments; fillers; blowing agents; thermal stabilizers; antioxidants; antistatic agents; reinforcing agents; metal scavengers or deactivators; impact modifiers; processing aids; mold release aids, lubricants; anti-blocking agents; flame retardant synergists; other flame retardants, including, for example, other mineral flame retardants; UV stabilizers; plasticizers; flow aids; and the like. Suitable flame retardant synergists include antimony trioxide, antimony pentoxide, sodium antimonate, zinc borate, mixed oxides of boron and zinc, alkaline earth borate (preferably calcium borate), mixtures of alkaline earth metal oxide (preferably calcium oxide) and an oxide of boron and/or zinc borate, barium sulfate, zinc sulfide, and the like, or any other suitable flame retardant synergist, provided the synergist does not materially interfere with the performance of the additive system employed.

[0043] The proportions of the other optional additives, although typically relatively small on an individual basis, are nevertheless at least sufficient to provide the functional effect for which they are designed or provided, and thus the proportions can thus be varied to suit the needs of any given situation. The particular materials selected for use should not materially affect adversely the properties of the finished polymer composition for its intended utility.

Preparing Flame Retarded Polymer Compositions

[0044] Various known procedures can be used to prepare the blends or formulations used in forming the molded polymer. For example a powdery blend of this invention can be blended with such other components, including the dry polymer resin, and thereafter the blend can be molded by extrusion, compression, or injection molding. Likewise the components can be mixed together in a B anbury mixer, a Brabender mixer, a roll mill, a kneader, or other similar mixing device, and then formed into the desired form or configuration such as by extrusion followed by comminution into granules or pellets, or by other known methods. Alternatively, the powdery blends of this invention can be separately dry mixed with the polymer apart from any other additive(s) and thereafter the final dry blend, including other additive(s) if used, can be molded or extruded. Similarly, the powdery blends of this invention can be separately introduced into and mixed with the polymer in its molten condition, before and/or after the inclusion in the polymer of any other additive(s). [0045] The powdery blends of this invention can be utilized in the formation of useful articles of the type normally fabricated by molding or extrusion of conventional flame retarded polymers. Likewise it is possible to prepare foamed or expanded shapes and objects from the compositions of this invention. Molding and extrusion conditions such as temperatures and pressures are within conventional recommended limits. Conditions normally used for producing foamed or expanded shapes and objects from flame retarded polymers can be used with the compositions of this invention, with little or no modification.

Test Methods

[0046] The Vibrating Funnel Test for measuring flowability of solids involves use of the following test procedure: A 100 gram sample of the material to be tested is weighed into a plastic cup with an accuracy of 0.1 g. To measure flowability, this 100 gram test sample is put into a steel funnel with an upper diameter of 150 mm, an opening diameter of 16 mm, and an angle of 31.5°. This funnel is mounted on a sieving machine, AS 200 Control, from Retsch GmbH. Before putting the sample into the funnel the outlet should be closed with a finger. Once the sample is in the funnel the sieving machine can be switched on and the finger can be removed once the selected vibration amplitude (0.5 or 1.5 mm) is reached. The time necessary to fully discharge the funnel is to be measured with a stop watch. The discharged sample can be collected in the previously used plastic cup. It is to be noted that the Vibrating Funnel Test can be used for measuring the flowability of either the powdery blends of this invention or of the silica used for further increasing the flowability of the powdery blends. [0047] A description of the method for determining viscosity by use of a Brookfield viscometer is as follows: To measure the viscosity the sample needs to be homogeneously mixed with the resin that is usually Palapreg P17-02 from DSM. The mixing step is conducted by use of a high shear mixer, for instance a high shear mixer from VMA Getzmann GmbH. To mix properly, a 100 g portion of the resin is poured into a plastic beaker and stirred with a dissolver disc of ca. 5 cm diameter at 2.0 rpm. The sample should be added to the resin stepwise, and once the addition is completed the stirrer speed is increased to 4.000 rpm for 3 min. Before measuring of the viscosity, the mix should be maintained in a water bath for 3-4 hours at 23 ⁰ C to reach standard conditions and to release air bubbles. Viscosity measurement is conducted with a Brookfield viscometer DVII+. Depending on the viscosity level of the sample being tested, a spindle of suitable dimensional stability is selected for use. Prior to the viscosity measurement, the zero point of the viscosimeter (a.k.a. viscometer) needs to be adjusted, using the manufacturer's instructions. Once adjusted and equipped with a suitable spindle, the sample-resin-mix is measured in a 180 mL plastic beaker. A value for each oscillating speed of the rotating spindle can be read on the screen of the viscometer. To calculate the final viscosity value the measured value should be corrected. The correcting factor is determined on every resin lot supplied so that the appropriate correction can be applied to the measured values obtained using that resin. To determine the correcting factor, the viscosity of the neat resin is measured. The conditions used both in determining the correcting factor and in determining viscosities of samples using this test procedure are temperature: 23 ⁰ C; vessel used: plastic beaker with 180 mL volume; and spindle operation: rotated at 2 and at 50 rpm.

[0048] The UL 94 flammability test uses specimens with a size of 127 mm x 12.7 mm x thickness. The thickness can vary depending on final requirements and is usually 1.6 mm or 3.2 mm. Prior to the fire test the specimens are stored at 23 ⁰ C and at 50% relative humidity for 16 hours. To conduct the fire test the specimen is fixed on the upper end to be vertically mounted. The distance from the lower end of the sample to the table is 305 mm. A cotton wood sample (50 x 50 x 6.5 mm) is placed under the specimen. A natural gas fired laboratory scale burner is adjusted having a 19 mm high non-luminous flame; with this adjustment the sample is treated twice for 10 seconds each (the second treatment starts if/when the sample stops burning from first flame treatment). The burning time as well as the glowing time of each flaming is measured with a stop watch. Also, formation of burning droplets igniting the cotton wool needs to be observed and recorded. Classification is as follows: For a V-O rating:

• no combustion occurs for longer than 10 second after the burner flame has been removed;

• the sum of burning times after removal of the burner flame in 10 determinations is not more than 50 seconds;

• no dripping of burning droplets occurs during the test;

• no complete burn-off of the sample occurs;

• no afterglow occurs for longer than 30 seconds after application of the burner flame. For a V-I rating:

• no combustion occurs for longer than 10 second after the burner flame has been removed;

• the sum of burning times after removal of the burner flame in 10 determinations is not more than 250 seconds; • no dripping of burning droplets occurs during the test;

• no complete burn-off of the sample occurs;

• no afterglow occurs for longer than 60 seconds after application of the burner flame.

For a V-2 rating: • ignition of the cotton wool occurs due to dripping of burning droplets;

• no combustion occurs for longer than 30 second after the burner flame has been removed; • the sum of burning times after removal of the burner flame in 10 determinations is not more than 250 seconds;

• no complete burn-off of the sample occurs;

• no afterglow occurs for longer than 60 seconds after application of the burner flame.

If no classification is possible into one of these three classes, this is noted in the test report with an indication that the results do not meet the requirements of the test. [0049] The mercury intrusion porosimetry test procedure for measuring specific pore volume involves use of the Porosimeter Pascal 140/440 instrument. The Pascal 140 instrument is able to measure pore radii down to ca. 2 μm(400 kPa); the Pascal 440 instrument can determine pore radii down to ca. 2 nm (400 MPa). The measuring of the porosity involves sample preparation, filling with mercury, measurement, analysis and calibration. Sample preparation includes cleaning and drying of the porosimeter followed by filling with 1.5 to 2 mL of mercury. Then the predried sample of ATH, boehmite or other filler is weighted into the sample holder (dilatometer). After that the dilatometer is tightly connected to the porosimeter. The dilatometer is than evacuated for 15 minutes so that the final pressure is ca. 0.01 kPa. Afterwards the dilatometer should be checked again to be tightly connected to the porosimeter. Then the dilatometer is pressurized with atmospheric pressure and filled with mercury. To analyze the data the Pascal 140/440 software has to be started. To calibrate the porosimeter a measurement has to be conducted only with mercury.

[0050] The test method for measuring bulk density of substances such as silica powder involves use of equipment consisting of a metal funnel and a cylinder of defined geometry (for standard procedure: Volume = 50 mL). The funnel is fixed in such a way that between its lower opening and the top rim of the cylinder there is a distance of 27 mm.

[0051] First the opening of the funnel is sealed with a finger. Then the sample material is put on the sieve inside the funnel. By release of the outlet the sample is allowed to flow into a dry and weighed (ml) cylinder. To make flowing of the powder easier, it can be moved slightly with a spatula. When the cylinder is filled completely, the excess of material is carefully removed with a smooth spatula. Any pressing of the sample material and vibration of the cylinder are to be avoided. The mass of the filled cylinder (m2) is determined and the bulk density is calculated. (m2 - ml) d = x 1000 g/kg

V where: d = bulk density in kg/m ³ ml = mass of the cylinder in g m2 = mass of the cylinder and sample in g

V = Volume of the cylinder in mL (= 50 mL)

[0052] The following Examples are presented for purposes of illustration. They are not intended to limit the invention to only the materials and methods described therein.

EXAMPLE 1

[0053] 100 Parts of pseudo boehmite type G45 (intermediate product used for production of catalyst carrier) from ALB Catalysts were blended with 192 parts of ANTIBLAZE ^® V490 flame retardant in a Henschel mixer at 3000 rpm for about 10 minutes without steam heating. The pseudo boehmite was introduced into the Henschel mixer first and the liquid was dosed slowly within a period of 20 seconds once the mixer had reached 3000 rpm. The flowability was measured by determining the time necessary for 100 g of the powder to flow through a vibrating funnel (amplitudes of 0.5 and 1.5 mm, testing apparatus from the Retsch company). At 0.5 mm the flow time was 20 seconds and at 1.5 mm the flow time was 25 seconds. For comparison, the flowability of each of MAGNIFIN ^® H 10 and pseudo boehmite type G45 was determined under the same conditions. With MAGNIFIN ^® H 10 the following flow times were found:

Amplitude Time 0.5 mm 28 seconds

1.5 mm 34 seconds

G45 gave the following flow times:

Amplitude Time 0.5 mm 85 seconds 1.5 mm 43 seconds

EXAMPLE 2

[0054] 100 Parts of pseudo boehmite grade G45 from ALB Catalysts were blended with

192 parts of NcendX ^® P30 flame retardant in the steam-heated Henschel mixer at 3000 rpm for about 10 min. The pseudo boehmite was introduced into the Henschel mixer first and the liquid was dosed slowly within a period of time of 20 seconds once the mixer had reached 3000 rpm. The NcendX ^® P30 flame retardant was preheated to approx. 100 ⁰ C to obtain reduced viscosity prior to blending. The flowability was measured as described in Example 1. This provided the following flow times: Amplitude Time

0.5 mm 12 seconds

1.5 mm 18 seconds

For comparison, the flowabilities of MAGNIFIN ^® H 10 and of pseudo boehmite grade G45 are as provided in Example 1.

EXAMPLE 3

[0055] 100 Parts of nanoboehmite ETE 08211 from Martinswerk GmbH were blended with 50 parts of Antiblaze V490 flame retardant in the Henschel mixer at 3000 rpm for about 10 minutes without steam heating. The nanoboehmite was introduced into the Henschel mixer first and the liquid was dosed slowly within a period of time of 20 seconds once the mixer had reached 3000 rpm.

[0056] The flowability was measured as described in Example 1 using a vibrating funnel. The flowability times were as follows:

Amplitude Time 0.5mm 21 seconds

1.5mm 13 seconds

The bulk density of this blend was determined by weighing the powder in a 50 mL metal cylinder resulting in a value of 444 kg/m ³ . For comparison, the flowabilities of MAGNIFIN H 10 and of pseudo boehmite grade G45 are provided in Example 1.

EXAMPLE 4

[0057] 100 Parts of nanoboehmite ETE 08211 from Martinswerk GmbH were blended with 50 parts of NcendX P30 flame retardant in the steam-heated Henschel mixer at 3000 rpm for about 10 min. The nanoboehmite was introduced into the Henschel mixer first and the liquid was dosed slowly within a period of time of 20 seconds once the mixer had reached 3000 rpm. The NcendX P30 flame retardant was preheated to approximately 100 ⁰ C to obtain reduced viscosity prior to blending. The flowability was measured as described in Example 1. The flowability values were as follows: Amplitude Time

0.5mm 4 seconds

1.5mm 4 seconds

The bulk density of this blend was determined as described in Example 3 resulting in a value of 778 kg/m ³ . For comparison, the flowabilities of MAGNIFIN H 10 and of G45 are provided in Example 1.

EXAMPLE 5 [0058] In order to obtain a flame retardant for unsaturated polyester resins 10 parts of pseudo boehmite G45 was blended with 20 parts of Antiblaze V490 flame retardant in the Henschel mixer at 3000 rpm for about 10 minutes without steam heating. The pseudo boehmite was introduced into the Henschel mixer first and the liquid was dosed slowly within a time of 20 seconds once the mixer has reached 3000 rpm. The resulting powder was blended with additional 70 parts of MARTIN AL ^® OL- 104 LEO (Martins werk GmbH) also at 3000 rpm without heating for about 10 minutes to finally obtain a powder blend. The flowability of this powder blend was determined as described in Example 1. The flow times were as follows:

Amplitude Time

0.5mm 15 second 1.5mm 17 seconds

For comparison, the flowabilities of MAGNIFIN H 10 and of G45 are provided in Example 1.

[0059] To determine the viscosity in unsaturated polyester resin, 100 parts by weight of the powdery blend formed in this Example were dispersed in 100 parts by weight of unsaturated polyester resin (P17-02) from DSM using a high shear mixing equipment. The viscosity was measured with a Brookfield viscometer using spindle 3 at 23 ⁰ C. At 5 rpm the viscosity was found to be 4.4 pascal- seconds (Pa*s). To determine fire performance (flame retardancy), 100 parts by weight of the powdery blend formed in this Example were dispersed in 100 parts by weight of unsaturated polyester resin P 17-02 to which 2.5 parts of peroxide (Butanox M-50, indicated to be methyl ethyl ketone peroxide in dimethyl phthalate; Akzo Nobel) and 0.5 parts Byk A 555 air release additive (BYK- Chemie) were added. After curing of this formulation in metal frames pieces for UL 94 test were cut with a band saw. At a thickness of 3.4 mm, a UL 94 V 0 rating was achieved.

EXAMPLE 6 - (COMPARATIVE) [0060] For comparison with Example 5, 100 parts of MARTINAL OL- 104 LEO were dispersed in 100 g polyester resin P 17-02 using high shear mixing equipment. The viscosity was measured under the same conditions as in Example 5 and was of about 12.9 pascal- seconds (Pa*s). To determine fire performance (flame retardancy), 100 parts by weight of OL- 104 LEO were dispersed in 100 parts by weight of unsaturated polyester resin P 17-02 to which 2.5 parts by weight of peroxide (Butanox M-50) and 0.5 parts of Byk A 555 had been added. After curing this formulation in metal frames, pieces for the UL 94 test were cut with a band saw. At a thickness of 3.4 mm, no UL 94 rating was achieved. In other words, the product was unable to pass the UL 94 test criterion for flame retardancy. Accordingly, a higher level of OL- 104 LEO was then employed. In particular, 130 parts of OL-104 LEO were dispersed in 100 parts polyester resin P 17-02 to which 2.5 parts peroxide (Butanox M-50) and 0.5 parts Byk A 555 were added. After curing of this formulation in metal frames pieces for UL 94 test were cut with the band saw. At a thickness of 3.4 mm UL 94 V 0 was achieved.

EXAMPLE 7

[0061] In order to obtain a flame retardant for unsaturated polyester resins with an even lower viscosity than the powdery blend formed in Example 5, 10 parts of pseudo boehmite G45 was blended with 20 parts of Antiblaze V490 in the Henschel mixer at 3000 rpm for about 10 minutes. The resulting free flowing powder was blended with an additional 70 parts of MARTINAL ON-921, an aluminum hydroxide with low viscosity behavior, to obtain a powder blend.

[0062] To determine viscosity in an unsaturated polyester resin, 175 parts of the free flowing powder blend of this invention formed in this Example, were dispersed in 100 parts of polyester resin P17-02 (from DSM) using high shear mixing equipment. The viscosity was measured with a Brookfield viscometer using spindle 3 at 23 ⁰ C. At 5 rpm the viscosity was found to be 5.6 pascal-seconds (Pa*s). EXAMPLE 8 - (COMPARATIVE)

[0063] For comparison with the results of Example 7, 175 parts of MARTINAL ON-921 were dispersed in 100 g of unsaturated polyester resin P 17-02 using the high shear mixing equipment. The viscosity of this product was measured under the same conditions as in Example 7 and was found to be about 23.3 pascal-seconds (Pa*s).

[0064] Components referred to by chemical name or formula anywhere in the specification or claims hereof, whether referred to in the singular or plural, are identified as they exist prior to coming into contact with another substance referred to by chemical name or chemical type (e.g., another component, a solvent, or etc.). It matters not what chemical changes, transformations and/or reactions, if any, take place in the resulting mixture or solution as such changes, transformations, and/or reactions are the natural result of bringing the specified components together under the conditions called for pursuant to this disclosure. Thus the components are identified as ingredients to be brought together in connection with performing a desired operation or in forming a desired composition. Also, even though the claims hereinafter may refer to substances, components and/or ingredients in the present tense ("comprises", "is", etc.), the reference is to the substance, component or ingredient as it existed at the time just before it was first contacted, blended or mixed with one or more other substances, components and/or ingredients in accordance with the present disclosure. [0065] Each and every patent or publication referred to in any portion of this specification is incorporated in toto into this disclosure by reference, as if fully set forth herein.

[0066] Except as may be expressly otherwise indicated, the article "a" or "an" if and as used herein is not intended to limit, and should not be construed as limiting, a claim to a single element to which the article refers. Rather, the article "a" or "an" if and as used herein is intended to cover one or more such elements, unless the text taken in context clearly indicates otherwise.

[0067] The invention may comprise, consist or consist essentially of the materials and/or procedures recited herein. [0068] This invention is susceptible to considerable variation in its practice. Therefore the foregoing description is not intended to limit, and should not be construed as limiting, the invention to the particular exemplifications presented hereinabove.