Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/32—Phosphorus-containing compounds
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B25/00—Phosphorus; Compounds thereof
  • C01B25/16—Oxyacids of phosphorus; Salts thereof
  • C01B25/18—Phosphoric acid
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B33/00—Silicon; Compounds thereof
  • C01B33/113—Silicon oxides; Hydrates thereof
  • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B33/00—Silicon; Compounds thereof
  • C01B33/20—Silicates
  • C01B33/32—Alkali metal silicates
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/34—Silicon-containing compounds
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K21/00—Fireproofing materials
  • C09K21/02—Inorganic materials
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K21/00—Fireproofing materials
  • C09K21/02—Inorganic materials
  • C09K21/04—Inorganic materials containing phosphorus
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/60—Particles characterised by their size
  • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer

Definitions

• ATH aluminum trihydroxide
• MDH magnesium hydroxide
• This invention is deemed to fulfill the foregoing advantage on an economically attractive basis.
• the crystal structures of the silicon-modified and/or phosphorus-modified compositions are related to hydrogarnet (i.e., M ⁇ 3M i ⁇ 2(OH)i2) and garnet (i.e., M ⁇ 3 M ⁇ i 2 (Si ⁇ 4 ) 3 ), but the flame retardants of this invention differ in composition and properties from both garnet and hydrogarnet.
• the silicon-modified and/or phosphorus- modified compositions have crystal shapes that are generally octahedral.
• the crystal shape of the hydrogarnet compounds of the invention that are not silicon-modified and/or phosphorus-modified is generally cubic. Hydrogarnet crystals produced by U.S. Pat. No. 3,912,671 were reported to spherical in shape; following the procedures disclosed therein yielded irregular isometric polyhedra.
• compositions of this invention have been found to have greater thermal stability than ordinary hydrogarnet.
• this invention provides, among other things, a flame retardant comprised of synthetic hydrogarnet optionally modified by inclusion of silicate and/or phosphate ions in its crystal structure. Also provided by this invention is a flame retardant as just described further characterized in that the crystal structure of the flame retardant is related to hydrogarnet, i.e., M ⁇ 3 M ra 2 (OH) 12 .
• Such synthetic flame retardants can be characterized by providing enhanced heat release characteristics when incorporated in suitable concentration in ethylene-vinyl acetate test pieces which are subjected to combustion in a cone calorimeter.
• time to reach a second heat release peak if a second heat release peak is even reached, is longer and the heat release of the second maximum (if present) is lower.
• the absence of a second peak or its lower maximum value is a consequence of a stronger char formation, preventing burnable gases to enter the gas phase and to feed the flame.
• this invention provides a synthetic inorganic modified hydrogarnet flame retardant characterized by (i) having the empirical formula M 11 S M 11 ⁇ O y (OH) i 2 - 5y - 4 ⁇ (P ⁇ 4 ) y (Si ⁇ 4 ) x wherein M 11 is one or a mixture of more than one alkaline earth metal, preferably Ca; and x and y are numbers in the range of 0 to about 1.5, with x + y in the range of 0 to about 1.5, preferably in the range of about 0.05 to about 1.5; a more preferred range is about 0.1 to about 1.5; even more preferred is about 0.05 to about 1.2; and (ii) having the following properties: a) a median particle size, dso, in the range of about 0.5 to about 10 ⁇ m as determined by laser diffraction; b) a surface area in the range of about 0.5 to about 30 m 2 /g as determined by BET, preferably between about 1 to about 30
• synthetic inorganic flame retardants as above that are further characterized by having a surface moisture content of ⁇ 0.7 wt%, preferably ⁇ 0.5 wt%, as determined by infrared moisture balance at 105 0 C, and a sodium oxide content of ⁇ 0.5 wt% as determined by flame photometry.
• this invention provides a process of preparing a synthetic inorganic hydrogarnet that is optionally modified with suitable amounts of silicate and/or phosphate, which process comprises: • agitating a mixture formed from
• a source of silicon especially an aqueous silicate solution, as for example, (i) one or more of the solutions of, e.g., NaSiO 3 or Na 2 Si 3 O 7 such as are commercially-available as "water glass” and/or (ii) amorphous or crystalline silicon dioxide in powder form), and/or
• a source of silicon especially an aqueous silicate solution, as for example, (i) one or more of the solutions of, e.g., NaSiO 3 or Na 2 Si 3 O 7 such as are commercially-available as "water glass” and/or (ii) amorphous or crystalline silicon dioxide in powder form), and/or
• a source of phosphorus especially an aqueous phosphate solution, e.g., phosphoric acid, alkali or ammonium phosphate salts such as Na 3 PO 4 , Na 2 HPO 4 , NaH 2 PO 4 , alkali or ammonium diphosphate salts such as Na 4 P 2 O 7 , and/or alkali or ammonium polyphosphate salts
• a source of phosphorus especially an aqueous phosphate solution, e.g., phosphoric acid, alkali or ammonium phosphate salts such as Na 3 PO 4 , Na 2 HPO 4 , NaH 2 PO 4 , alkali or ammonium diphosphate salts such as Na 4 P 2 O 7 , and/or alkali or ammonium polyphosphate salts
• the proportions of the Group IIIA metal source and the Group HA metal source used in forming the mixture are in a molar ratio of Group IIA metal:Group IIIA metal in the range of about 1:1 to about 2:1.
• the source of silicon used in forming the mixture provides silicate in amounts in the range of about 0.05 to about 1.5 moles of silicate per mole of modified synthetic inorganic hydrogarnet prepared, and/or when present, the source of phosphorus used in forming the mixture provides phosphate in amounts in the range of about 0.05 to about 1.5 moles of phosphate per mole of modified synthetic inorganic hydrogarnet prepared.
• Preferred proportions of the source of silicon used in forming the mixture and/or the source of phosphorus used in forming the mixture provide silicate and/or phosphate in amounts in the range of about 0.1 to about 1.5 moles, more preferably in the range of about 0.05 to about 1.2 moles, of silicate and/or phosphate per mole of modified synthetic inorganic hydrogarnet prepared.
• each atom of silicon from the silicon source forms one silicate ion in the modified synthetic inorganic hydrogarnet
• each atom of phosphorus from the phosphorus source forms one phosphate ion in the modified synthetic inorganic hydrogarnet.
• a preferred process of this invention relates to the production of a synthetic flame retardant, which is modified by the incorporation therein of suitable amounts of silicate and/or phosphate. This process comprises:
• the aluminum source being (i) aluminum hydroxide, boehmite, pseudo boehmite, aluminum oxide, or mixtures of any two or more of the foregoing, and (ii) in powder form
• the calcium source being (i) an inorganic salt, hydroxide, or oxide of calcium, including hydrates thereof, and (ii) in powder form;
• the proportions of aluminum source and calcium source used in forming the mixture provide a molar ratio of Ca:Al in the range of about 1:1 to about 2:1
• the source of silicon used in forming the mixture provides silicate in amounts in the range of about 0.05 to about 1.5 moles, preferably in the range of about 0.1 to about 1.5 moles, more preferably in the range of about 0.05 to about 1.2 moles, of silicate per mole of synthetic flame retardant produced, and/or the source of phosphorus used in forming the mixture provides phosphate in amounts in the range of about 0.05 to about 1.5 moles, preferably in the range of about 0.1 to about 1.5 moles, more preferably about 0.05 to about 1.2 moles, of phosphate per mole of synthetic flame retardant produced.
• Fig. 1 shows cone calorimeter heat release rate curves for Example 6 (inventive) and Example 9 (comparative).
• FIG. 2 shows cone calorimeter heat release rate curves for Examples 7 (inventive) and Example 9 (comparative).
• FIG. 3 shows cone calorimeter heat release rate curves for Example 8 (inventive) and Example 9 (comparative).
• Fig. 4 shows cone calorimeter heat release rate curves for Example 10 (inventive) and Example 12 (comparative).
• Fig. 5 shows cone calorimeter heat release rate curves for Example 11 (inventive) and Example 12 (comparative).
• Fig. 6 shows an SEM micrograph of a modified hydrogarnet made as in Example
• Fig. 7 shows an SEM micrograph of a hydrogarnet made as in Example 5.
• Fig. 8 shows an SEM micrograph of a hydrogarnet made as in U.S. 3,912,671.
• the structures of the compounds of the invention in which silicate and/or phosphate ions are present can be thought of as having the same arrangement of atoms as hydrogarnet, with some groupings of four hydroxide ions exchanged for a silicate or phosphate ion; in the crystal structures, the four oxygen atoms of the silicate or phosphate ion are believed to be in the same place as were the oxygen atoms of the four hydroxide ions.
• novel flame retardants of this invention can be represented by the following general formula (1):
• M 11 is a Group HA metal atom, typically Ca, Sr, or Ba, or a mixture of at least two of these, or a mixture of any one or more of these with a minor proportion (i.e., less than about 50% by weight) of Mg;
• M 111 is a Group IIIA metal atom, especially aluminum, but which may be in admixture with small amounts (e.g., less than about 20 % by weight) of B, Ga, In, or Tl, or a mixture of any two or more of these; and where x and y are numbers in the range of 0 to about 1.5, with x + y in the range of 0 to about 1.5, preferably in the range of about 0.05 to about 1.5, more preferably in the range of about 0.1 to about 1.5, even more preferred is about 0.05 to about 1.2.
• the product can be represented by the formula M ⁇ 3 M ra 2 (OH) 12 , where M 11 and M 111 are as in formula (1) above.
• the product can be represented by the following general empirical formula:
• M 11 and M 111 are as in formula (1) above, and x is in the range of about 0.05 to about 1.5, preferably in the range of about 0.1 to about 1.5, more preferably in the range of about 0.05 to about 1.2.
• the product can be represented by the following general empirical formula:
• M 11 and M 111 are as in formula (1) above, and y is in the range of about 0.05 to about 1.5, preferably in the range of about 0.1 to about 1.5, more preferably in the range of about 0.05 to about 1.2.
• Preferred flame retardants of this invention can be represented by the following general empirical formula (2):
• M 11 is a Group HA metal atom, typically Ca, Sr, or Ba, or a mixture of at least two of these, or a mixture of any one or more of these with a minor proportion (i.e., less than about 50% by weight) of Mg; and where x and y are numbers in the range of 0 to about 1.5, with x + y in the range of about 0 to about 1.5, preferably in the range of about 0.05 to about 1.5; more preferably in the range of about 0.1 to about 1.5, even more preferably in the range of about 0.05 to about 1.2.
• the presence of trace amounts of other metal atoms that do not adversely affect the flame retardant and thermal stability properties of the flame retardant can be present.
• the product When no silicon or phosphorus source is used in synthesizing the product, the product can be represented by the formula M ⁇ 3 Al 2 (OH)i 2 , where M 11 is as in formula (2) above. When no phosphorus source is used in synthesizing the product, the product can be represented by the following general empirical formula:
• M 11 is as in formula (2) above, and x is in the range of about 0.05 to about 1.5, preferably in the range of about 0.1 to about 1.5, more preferably in the range of about 0.05 to about 1.2.
• the product can be represented by the following general empirical formula:
• Especially preferred flame retardants of this invention can be represented by the following general empirical formula (3):
• x and y are numbers in the range of 0 to about 1.5, with x + y in the range of about 0 to about 1.5, preferably in the range of about 0.05 to about 1.5; more preferred ranges are about 0.1 to about 1.5 and about 0.05 to about 1.2.
• the presence of trace amounts of other metal atoms that do not adversely affect the flame retardant and thermal stability properties of the flame retardant can be present.
• the product can be represented by the formula Ca 3 Al 2 (OH) I2 .
• the product can be represented by the following general empirical formula:
• x is in the range of about 0.05 to about 1.5, preferably in the range of about 0.1 to about 1.5, more preferably in the range of about 0.05 to about 1.2.
• the product can be represented by the following general empirical formula:
• y is in the range of about 0.05 to about 1.5, preferably in the range of about 0.1 to about 1.5, more preferably in the range of about 0.05 to about 1.2.
• the flame retardants of this invention are flame retardants of increased effectiveness and are further characterized by having enhanced thermal stability. It is also believed that by virtue of the inclusion of silicate and/or phosphate in the crystal structure, the resultant crystal growth characteristics of the flame retardants of this invention can be influenced in a favorable manner. This in turn could have a beneficial influence on various characteristics of the flame retardants, such as purity.
• flame retardants of this invention flame retardants of formulas (1), (IA), (IB), (2), (2A), (2B), (3), (3A), or (3B) above
• at least about 98% by weight of M 11 is Ca
• at least about 98% by weight of M 111 is Al.
• the flame retardants of this invention are useful for a wide variety of flame retardant applications. For example they can be effectively utilized in a wide variety of polymers such as thermoplastic and thermosetting polymers and resins and in elastomers (e.g., natural and synthetic rubbers). 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 like epoxy resins for printed circuit boards. In some of these applications, the improved thermal stability provided by the incorporation of silicate and/or phosphate moieties into the flame retardant is of considerable importance, even though numerically, the number of degrees centigrade ( 0 C) of enhanced thermal stability relative to comparable conventional materials may appear relatively small.
• Group HA compounds include magnesium bromide, magnesium chloride, magnesium iodide, magnesium hydroxide, magnesium oxide, magnesium nitrate, magnesium phosphate, magnesium sulfate, calcium bromide, calcium chloride, calcium iodide, calcium hydroxide, calcium oxide, calcium nitrate, calcium phosphate, calcium sulfate, strontium bromide, strontium chloride, strontium iodide, strontium hydroxide, strontium oxide, strontium nitrate, strontium phosphate, strontium sulfate, barium bromide, barium chloride, barium iodide, barium hydroxide, barium oxide, barium nitrate, barium phosphate, barium sulfate, or mixtures of any two or more of the foregoing.
• the Group HA raw material(s) used can be one or more than one inorganic salt of a Group HA metal or mixtures of Group HA metals, or mixtures of one or more than one inorganic Group HA metal salt with a minor amount of another Group HA metal salt, e.g., calcium hydroxide or calcium oxide having therein magnesium hydroxide or oxide.
• another Group HA metal salt e.g., calcium hydroxide or calcium oxide having therein magnesium hydroxide or oxide.
• calcium compounds devoid of halogen are preferred; more preferred are calcium hydroxide and calcium oxide.
• the median particle size, dso, of the starting material is ⁇ 50 ⁇ m, preferably ⁇ 10 ⁇ m, and more preferably ⁇ 2 ⁇ m.
• Group MA compounds can be used as raw materials for the preparation of flame retardants of this invention.
• Non-limiting examples of such Group MA compounds include aluminum hydroxide, boehmite, pseudo boehmite, aluminum oxide, aluminum bromide hexahydrate, aluminum chloride hexahydrate, aluminum iodide hexahydrate, aluminum nitrate and its hydrate, aluminum sulfate and its hydrates, aluminum phosphate, gallium nitrate, gallium oxide, gallium oxychloride, gallium sulfate, gallium trichloride, gallium tribromide, indium trichloride, indium nitrate, indium sulfate, or mixtures of any two or more of the foregoing.
• the aluminum compounds devoid of halogen are preferred.
• the median particle size, dso, of the starting material is ⁇ 50 ⁇ m, preferably ⁇ 30 ⁇ m, and more preferably ⁇ 20 ⁇ m.
• the starting material is milled by any suitable dry or wet milling process known in the art to obtain the desired particle size distribution.
• the milling process can be applied to i) only the Group HA source; ii) only the Group MA source; iii) both the Group HA and Group MA source; or iv) a mixture of the Group HA source and Group MA source in the molar ratio desired for synthesis of the inventive product.
• the particle size of the product has been observed to be influenced by the particle size of the Group HA metal salt.
• larger particle sizes of the Group HA metal salt lead to larger particle sizes of the product.
• the product often also forms agglomerates. Milling of the Group HA metal salt is a preferred way to minimize or eliminate agglomeration.
• the source of silicon used in the preparation of the flame retardants of this invention can vary.
• an aqueous silicate solution as for example, (i) one or more of the solutions of, e.g., NaSiO 3 or Na 2 Si 3 O 7 such as are commercially- available as "water glass” and/or (ii) amorphous or crystalline silicon dioxide in powder form.
• the source of phosphorus can be an aqueous phosphate solution, e.g., phosphoric acid, alkali or ammonium phosphate salts such as Na 3 PO 4 , Na 2 HPO 4 , NaH 2 PO 4 , alkali or ammonium diphosphate salts such as Na 4 P 2 O 7 , and/or alkali or ammonium polyphosphate salts; all of these phosphorus compounds and their respective hydrates as solids or in aqueous solution.
• alkali or ammonium phosphate salts such as Na 3 PO 4 , Na 2 HPO 4 , NaH 2 PO 4
• alkali or ammonium diphosphate salts such as Na 4 P 2 O 7
• alkali or ammonium polyphosphate salts alkali or ammonium polyphosphate salts
• the reactor It is desirable to initially charge the reactor with at least some of the water that will form the aqueous phase, charge thereto the appropriate proportions of the Group II metal source and the Group M metal source (either separately or as a preformed mixture), and thereafter charge the silicon source and/or phosphorus source, if used. If desired, the silicon source and/or phosphorus source may be added before the Group II metal source and/or the Group M metal source.
• the mixture formed from a Group MA metal source, a Group IIA metal source, optional source of silicon and/or phosphorus, and an alkali metal hydroxide should be a substantially uniform mixture. Therefore, the mixture is thoroughly agitated and mixed so that a mixture of substantially uniform makeup is formed.
• This mixture is typically heated and agitated while at one or more elevated temperatures such as, for example, temperatures in the range of about 50 to about 100 0 C.
• the agitation and mixing of the components under these temperature conditions is conducted for a period of time at least sufficient to form a flame retardant product of this invention. Ordinarily, the length of this period of heating is not critical, since it can vary depending upon the temperature used and the extent of the uniformity of the mixture as it is being agitated.
• the mixture will be agitated or stirred and mixed while at such elevated temperature(s) for a total period of at least about 10 minutes, and in some cases at least about 30 minutes.
• Any suitable reaction temperature or sequence of reaction temperatures yielding an acceptable reaction rate can be used.
• the reaction is performed at temperatures in the range of about 50 to about 100 0 C. It should be noted that this reaction is not a precipitation reaction, but instead is a recrystallization via partially solution where at no time all of either calcium or aluminum is completely dissolved.
• the obtained suspension of the flame retardant according to the present invention is then filtered and washed to remove impurities therefrom, thus forming a filter cake.
• the filter cake is then dried by any method known in the art to dry a filter cake.
• the filter cake is dried using spin-flash dryers, other continuously operating flash dryers or cell mills techniques in the production of mineral fillers.
• the filter cake is transferred to the dryer using a, depending on the consistency of the filter cake, suitable feeding equipment, e.g., a screw conveyer, and dispersed with one or more rotors.
• Hot gas typically air, is induced to the dryer providing the energy for the fast evaporation of the water included in the filter cake.
• the hot gas stream carries the fine de- agglomerated particles further downstream.
• the gas stream can be led through a classifying device to return coarse particles to the dispersion zone for further processing.
• the filter cake is suspended with water to form a slurry.
• a dispersing agent is added to the filter cake to form a slurry.
• dispersing agents include polyacrylates, organic acids, naphthalensulfonate/formaldehyde condensate, fatty- alcohol-polyglycol-ether, polypropylene-ethyleneoxide, polyglycol-ester, polyamine- ethyleneoxide, sodium polyphosphate, sodium tripolyphosphate, and polyvinylalcohol.
• the slurry is then dried by any method known in the art to dry a slurry.
• This technique generally involves the atomization of a mineral filler feed through the use of nozzles and/or rotary atomizers.
• the atomized feed is then contacted with a hot gas, typically air, and the spray dried product is then recovered from the hot gas stream.
• the contacting of the atomized feed can be conducted in either a counter-current or co-current fashion, and the gas temperature, atomization, contacting, and flow rates of the gas and/or atomized feed can be controlled to produce filler particles having desired product properties.
• the recovery of the dried product can be achieved through the use of recovery techniques such as filtration, e.g., using fabric filters, or just allowing the dried particles to fall to collect in the drier where they can be removed, but any suitable recovery technique can be used.
• the product is recovered from the drier by using particle filters and allowing the product to settle at the bottom of the filter housing, using screw conveyors to recover it from there and subsequently convey it through pipes into a silo by means of compressed air.
• the drying conditions are conventional and are readily selected by one having ordinary skill in the art. Generally, these conditions include inlet air temperatures typically between 250 and 65O 0 C and outlet air temperatures typically between 105 and 15O 0 C.
• the flame retardants according to the present invention can be used as a flame retardant in a variety of synthetic resins.
• thermoplastic resins where the flame retardant according to the present invention find use include polyethylene, polypropylene, ethylene -propylene copolymer, polymers and copolymers of C 2 to Cs olefins ( ⁇ -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-propy
• 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 (lattices).
• the synthetic resin is a polyethylene-based resin such as high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultra low-density polyethylene, EVA (ethylene- vinyl acetate resin), EEA (ethylene-ethyl acrylate resin), EMA (ethylene-methyl acrylate copolymer resin), EAA (ethylene-acrylic acid copolymer resin) and ultra high molecular weight polyethylene; and polymers and copolymers of C 2 to Cs olefins ( ⁇ -olefin) such as polybutene and poly(4-methylpentene-l), polyvinyl chloride and rubbers.
• the synthetic resin is a polyethylene-based resin.
• the present invention relates to a flame retarded polymer formulation comprising at least one synthetic resin, selected from those described above, in some embodiments only one and a flame retarding amount of the flame retardant according to the present invention, and optionally other flame retardants, and finished articles made from the flame retarded polymer formulation, e.g., by extrusion or molding processes.
• a flame retarding amount of the flame retardant according to the present invention it is generally meant in the range of from about 5 wt% to about 90 wt%, based on the weight of the flame retarded polymer formulation, and more preferably from about 10 wt% to about 60 wt%, on the same basis. In a most preferred embodiment, a flame retarding amount is from about 30 wt% to about 60 wt% of the flame retardant according to the present invention, on the same basis.
• other flame retardants or combinations of different other flame retardants can be added to the polymer formulation.
• additional flame retardants are mineral flame retardants like aluminum hydroxides, magnesium hydroxides, boehmites, layered double hydroxides (LDH), organically modified LDHs, clays, organically modified nano-clays, zinc borates, zinc stannates and zinc hydroxy stannates, brominated flame retardants, phosphorus containing flame retardants, nitrogen containing flame retardants and the like.
• the combinations of (i) synthetic hydrogarnet, whether unmodified or modified by inclusion of silicate and/or phosphate ions in its crystal structure, and (ii) at least one other mineral flame retardant such as described in this paragraph are typically used in relative amounts such that the (i):(ii) weight ratio is in the range of 99:1 to 1:99, and preferably in the range of 95:5 to 5:95.
• the total amount of such flame retardant combination used in or with a polymer is an amount that is at least sufficient to flame retard the polymer being used.
• the flame retarded polymer formulation can also contain other additives commonly used in the art.
• Non-limiting examples of other additives that are suitable for use in the flame retarded polymer formulations of the present invention include extrusion aids such as polyethylene waxes, Si-based 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; antiblocking agents; other flame retardants; UV stabilizers; plasticizers; flow aids; and the like.
• extrusion aids such as polyethylene waxes, Si-based extrusion aids, fatty acids
• coupling agents such as amino-, vinyl- or alkyl silanes or maleic acid grafted polymers
• each of the above components, and optional additives if used can be mixed using a Buss Ko-kneader, internal mixers, Farrel continuous mixers or twin screw extruders or in some cases also single screw extruders or two roll mills.
• the flame retarded polymer formulation can then be molded or extruded in a subsequent processing step.
• apparatuses can be used that thoroughly mix the components to form the flame retarded polymer formulation and also mold an article out of the flame retarded polymer formulation.
• any extrusion technique known to be effective with the synthetic resins mixture described above can be used.
• the synthetic resin, the flame retardant according to the present invention, and optional components, if chosen are compounded in a compounding machine to form a flame-retardant resin formulation as described above.
• the flame -retardant resin formulation is then heated to a molten state in an extruder, and the molten flame-retardant resin formulation is then extruded through a selected die to form an extruded article or to coat for example a metal wire or a glass fiber used for data transmission.
• the flame retarded polymer formulation of the present invention also comprises at least one, in some cases more than one, synthetic resin selected from thermosetting resins.
• thermosetting resins include epoxy resins, novolac resins, phosphorus-containing resins like DOPO, modified epoxy resins such as, for examples, brominated epoxy resins, unsaturated polyester resins and vinyl esters.
• the flame retarded resin formulation can also contain other additives commonly used in the art.
• Non-limiting examples of other additives that are suitable for use in the flame retarded polymer formulations of the present invention in addition to those cited above, include solvents, curing agents such as hardeners or accelerators, dispersing agents or fine silica.
• thermosetting polymer formulation other flame retardants or combinations of different other flame retardants can be added to the thermosetting polymer formulation.
• additional flame retardants are mineral flame retardants like aluminum hydroxides, magnesium hydroxides, boehmites, layered double hydroxides (LDH), organically modified LDHs, clays, organically modified nano-clays, zinc borates, zinc stannates and zinc hydroxy stannates, brominated flame retardants, phosphorus containing flame retardants, nitrogen containing flame retardants and the like.
• thermosetting polymer formulation is an amount that is at least sufficient to flame retard the thermosetting polymer formulation being used.
• thermosetting polymer formulation The proportions of the other optional additives are conventional and can be varied to suit the needs of any given situation.
• the preferred method of incorporation and addition of the components of the thermosetting polymer formulation is by high shear mixing. For example, by using a high shear mixer manufactured for example by the Silverson company. Further processing of the resin-filler mix is common state of the art and described in the literature. For example, for cured laminates, further processing of the resin-filler mix to the "prepreg" stage and then to the cured laminate is described in the "Handbook of Epoxide Resins", published by the McGraw-Hill Book Company, which is incorporated herein in its entirety by reference.
• the flame retarded polymer formulation of the present invention also comprises at least one, in some cases more than one, polymer-modified bitumen.
• polymer-modified bitumens include those modified with polypropylene and those modified with styrene-butadiene- styrene rubber.
• the flame retarded bitumen formulation can also contain other additives commonly used in the art.
• Non-limiting examples of other additives that are suitable for use in the flame retarded polymer formulations of the present invention are the other additives described above.
• other flame retardants or combinations of different other flame retardants can be added to the polymer- modified bitumen formulation.
• FIG. 1 A flame retarded polymer formulation comprising at least one synthetic resin or rubber and in the range of from about 5 wt% to about 90 wt% of at least one flame retardant comprised of synthetic hydrogarnet optionally modified by inclusion of silicon atoms and/or phosphorus atoms in its crystal structure, wherein said synthetic hydrogarnet has a cubic crystal shape when not modified by inclusion of silicon atoms and/or phosphorus atoms, and, optionally, at least one other flame retardant additive.
• a flame retarded polymer formulation comprising at least one polymer- modified bitumen and in the range of from about 5 wt% to about 90 wt% of at least one flame retardant comprised of synthetic hydrogarnet optionally modified by inclusion of silicon atoms and/or phosphorus atoms in its crystal structure, wherein said synthetic hydrogarnet has a cubic crystal shape when not modified by inclusion of silicon atoms and/or phosphorus atoms, and, optionally, at least one other flame retardant additive.
• said flame retardant additive is selected from aluminum hydroxides, magnesium hydroxides, boehmites, layered double hydroxides, organically modified layered double hydroxides, clays, organically modified nano-clays, zinc borates, zinc stannates and zinc hydroxy stannates, brominated flame retardants, phosphorus containing flame retardants, nitrogen containing flame retardants.
• the resultant mixture in the form of a slurry is then filtered via a filter press and washed with distilled water until a conductivity of ⁇ 500 ⁇ S of the washing water is reached.
• the filter cakes are recombined and reslurried in water.
• the resultant slurry is then dried in a B ⁇ chi laboratory spray drier, type B-290, operated at 22O 0 C inlet temperature and about 8O 0 C outlet temperature.
• the rate of water evaporation is approximately one liter per hour.
• BET surface area was measured according to DIN-66132.
• the appropriate parameters for the sample i.e., the refractive index and measurement conditions including the PIDS detectors for the nano range. Thereafter, the size distribution data are collected at intervals of 90 seconds and analyzed according to Mie scattering theory.
• To prepare the water/dispersant solution used in these determinations it is convenient to initially prepare a concentrate from 500 grams of Calgon ® dispersant, available from KMF Laborchemie, and 3 liters of CAL Polysalt, available from BASF. This solution is made up to 10 liters with deionized water. Then, 100 ml of this original 10 liters is taken and in turn diluted further to 10 liters with deionized water, and this final solution is used as the water-dispersant solution described above.
• TGA Thermogravimetric analysis
• X-Ray powder diffraction is carried out on a Siemens D500 instrument equipped with Bragg-Brentano focusing, applying a copper anode with a nickel filter for monochromatization.
• the initial charges to the 20-liter vessel were 4 liters of water, followed by 324 g NaOH. This mixture was heated while stirring to 95 0 C at a rate of about 15 0 C per minute. At reaching the desired temperature, 413 grams of fine precipitated aluminum trihydrate, and then 587 grams of calcium hydroxide, then 93 g of water glass (Na 2 Si 3 O 7 ) sodium silicate solution, having a calculated SiO 2 concentration of 27 wt% (available from Riedel-de Haen), were added. This provides a theoretical amount of silicate equivalent to 0.15 mole per mole of synthetic flame retardant, giving the product Ca 3 Al 2 (OH) H 4 (SiO 4 ) O is.
• the initial charges to the 20-liter vessel were 4 liters of water, followed by 444 g NaOH. This mixture was heated while stirring to 95 0 C at a rate of about 15 0 C per minute. At reaching the desired temperature, 413 grams of fine precipitated aluminum trihydrate, and then 587 grams of calcium hydroxide, then 185 g of water glass (Na 2 Si 3 O 7 ) sodium silicate solution, having a calculated SiO 2 concentration of 27 wt% (available from Riedel-de Haen), were added. This provides a theoretical amount of silicate equivalent to 0.3 mole per mole of synthetic flame retardant, giving the product Ca 3 Al 2 (OH)io 8(SiO 4 )O 3 . The mixture was maintained at this temperature, while stirring, for two hours. Results of analytical determinations of this resultant synthetic inorganic modified flame retardant are summarized in Table 1.
• the initial charges to the 20-liter vessel were 14.2 liters of water, followed by 3.55 kg Solvay liquor with NaOH cone, of 50 wt.%. This mixture was heated while stirring to 95 0 C at a rate of about 15 0 C per minute. At reaching the desired temperature, 1850 grams of fine precipitated aluminum trihydrate, and then 2340 grams of calcium hydroxide, then 750 g of water glass (Na 2 Si 3 O ? ) sodium silicate solution, having a calculated SiO 2 concentration of 27 wt% (available from Riedel-de Haen), were added.
• the initial charges to the 20-liter vessel were 4 liters of water, followed by 705 g NaOH. This mixture was heated while stirring to 95 0 C at a rate of about 15 0 C per minute. At reaching the desired temperature, 413 grams of fine precipitated aluminum trihydrate, and then 587 grams of calcium hydroxide, then 92 g of phosphoric acid with a concentration of 85 wt% H 3 PO 4 were added. This provides a theoretical amount of phosphate equivalent to 0.3 mole per mole of synthetic flame retardant, giving the product Ca 3 Al 2 Oo 3 (OH)io 5 (P0 4 )o 3 . The mixture was maintained at this temperature, while stirring, for two hours. Results of analytical determinations of this resultant synthetic inorganic modified flame retardant are summarized in Table 1.
• Table 1 shows that the inventive flame retardant materials have a significantly higher thermal stability than Aluminium Trihydrate (ATH), represented by the commercially available ATH flame retardant Martinal OL- 104 LEO produced by Martinswerk GmbH. It further shows the enhanced thermal stability of silicate and phosphate modified hydrogarnet materials (Examples 1-4) when compared to the unmodified hydrogarnet (Example 5).
• ATH Aluminium Trihydrate
• EVA ethylene-vinyl acetate copolymer
• EscoreneTM Ultra ULOOl 19 from ExxonMobil was mixed for about 20 minutes on a two roll mill W150M from the Collin company with 150 phr (about 595.3 g) of the inventive flame retardant produced in Example 1, together with 1.2 phr (about 4.8 g) of the amino silane AMEO from Evonik and 0.75 phr (about 3.0 g) of pentaerythritol tetrakis(3-(3,5-di-tert- butyl-4-hydroxyphenyl)propionate) (Ethanox ® 310 antioxidant from Albemarle Corporation).
• EVA ethylene-vinyl acetate copolymer
• Fig. 1 shows the cone calorimeter heat release rate curve, measured at 35 kW/m 2 on 3 mm thick compression molded plates.
• Table 2 presents some characteristic values of the cone curve (i.e., PHRR, TTI, MARHE, and the heat release rate (HRR) and the time of the second maximum).
• EVA ethylene-vinyl acetate copolymer
• EscoreneTM Ultra ULOOl 19 from ExxonMobil was mixed for about 20 minutes on a two roll mill W150M from the Collin company with 150 phr (about 595.3 g) of the inventive flame retardant produced in Example 2, together with 1.2 phr (about 4.8 g) of the amino silane AMEO from Evonik and 0.75 phr (about 3.0 g) of pentaerythritol tetrakis(3-(3,5-di-tert- butyl-4-hydroxyphenyl) propionate) (Ethanox® 310 antioxidant from Albemarle Corporation).
• EVA ethylene-vinyl acetate copolymer
• Fig. 2 shows the cone calorimeter heat release rate curve, measured at 35 kW/m 2 on 3 mm thick compression molded plates. Table 2 presents some characteristic values of the cone curve (i.e., PHRR, TTI, MARHE, and the heat release rate (HRR) and the time of the second maximum).
• Fig. 3 shows the cone calorimeter heat release rate curve, measured at 35 kW/m 2 on 3 mm thick compression molded plates. Table 2 presents some characteristic values of the cone curve (i.e., PHRR, TTI, MARHE, and the heat release rate (HRR) and time of the second maximum).
• Figs. 1, 2, and 3 show the cone calorimeter heat release rate curve, measured at 35 kW/m 2 on 3 mm thick compression molded plates.
• Table 2 presents some characteristic values of the cone curve (i.e., PHRR, TTI, MARHE, and the heat release rate (HRR) and the time of the second maximum).
• Examples 6, 7, and 8 are Examples of the present invention, whereas Example 9 is a comparative Example.
• Table 2 shows that inventive Examples 6, 7, and 8 all show a significantly longer "time to second peak" than the comparative Example 9, which indicates the state of the art for mineral flame retardant fillers. Also, it should be noted that the heat release rate of the second peak is significantly lower for inventive Examples 6, 7, and 8 than for Example 9, both as regards the absolute value as well as the value in relation to the PHRR of the respective Example.
• Fig. 4 shows the cone calorimeter heat release rate curve, measured at 35 kW/m on 3 mm thick compression molded plates. Table 3 presents some characteristic values of the cone curve (i.e., PHRR, TTI, MARHE and the heat release rate (HRR) and the time of the second maximum).
• Fig. 5 shows the cone calorimeter heat release rate curve, measured at 35 kW/m on 3 mm thick compression molded plates. Table 3 presents some characteristic values of the cone curve (i.e., PHRR, TTI, MARHE and the heat release rate (HRR) and the time of the second maximum).
• Figs. 4 and 5 show the cone calorimeter heat release rate curve, measured at 35 kW/m 2 on 3 mm thick compression molded plates. Table 3 presents some characteristic values of the cone curve (i.e., PHRR, TTI, MARHE and the heat release rate (HRR) and the time of the second maximum).
• the time value corresponding to the second maximum of the cone curve is generally correlated with the char forming potential of a filler: the stronger the char, the longer it will take for this second peak to appear.
• Table 3 shows that inventive Examples 10 and 11 show a significantly longer "time to second peak" than comparative Example 12.
• Example 12 indicates the state of the art for mineral flame retardant fillers. Also, it should be noted that the heat release rate of the second peak is significantly lower for inventive Examples 10 and 11 than for comparative Example 12.
• the invention may comprise, consist or consist essentially of the materials and/or procedures recited herein.

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