RU2812784C1 - Method for obtaining phosphorus-containing fire-resistant agents and their application in polymer compositions - Google Patents

Abstract

FIELD: polymer compositions.

SUBSTANCE: group of inventions can be used for high-temperature processing of polymer compositions. The method for producing a phosphorus-containing fire-resistant agent involves interaction at a temperature of 105°C or higher of a metal compound with a stoichiometric excess of an alkyl-substituted phosphonic acid. The metal compound is an oxide or alkoxide of aluminium or iron. Alkyl-substituted phosphonic acid is in a molten state at the reaction temperature. The molar ratio of alkyl-substituted phosphonic acid and metal compound is above 4:1. A variant of the method for producing a phosphorus-containing fire-resistant agent, a phosphorus-containing fire-resistant agent and a fire-resistant material are also proposed.

EFFECT: group of inventions makes it possible to increase the thermal stability of a phosphorus-containing fire-resistant agent.

24 cl, 1 dwg, 5 tbl, 7 ex

Description

This application claims priority to U.S. Provisional Patent Application No. 62/782,948, filed December 20, 2018, and U.S. Provisional Patent Application No. 62/923,446, filed Oct. 18, 2019, both of which are in their entirety. are incorporated herein by reference.

A highly effective, thermally stable phosphorus-containing flame retardant is prepared by a process involving reacting a metal or a suitable metal compound with a stoichiometric excess of a phosphonic or pyrophosphonic acid. The chemical composition of the resulting flame retardant, which in many embodiments is provided as a single or predominantly single compound, results in excellent flame retardancy and exhibits high thermal stability. The flame retardants disclosed herein are useful, for example, in polymer compositions, especially thermoplastics processed at high temperatures, in a wide range of applications.

BACKGROUND OF THE INVENTION

Phosphonic acid salts, that is, compounds of the formula given immediately below, are known flame retardants in many polymer compositions:

where R is an optionally substituted alkyl, aryl, alkylaryl or arylalkyl group, p is typically a number from 1 to 4, M is a metal, and y is typically a number from 1 to 4, so that M ^(+)y is metal cation, where (+)y represents the charge formally assigned to the cation.

As disclosed in US patent application US 2007/0029532, decomposition of phosphonic acid salts at temperatures encountered during processing of polyesters and polyamides is known, damaging these polymers in the process, for example, temperatures above 260 or 270°C.

US Patent US 5,053,148 discloses that brittle, heat-resistant foams can be produced by heating phosphonic acid salts at elevated temperatures.

In comparative examples 1 and 2 from US patent US 9,745,449, glass fiber-filled polyamide compositions containing from 10 to 25% wt. aluminum salt of methylphosphonic acid were processed at elevated temperatures. During compounding, a reduction in torque was observed, indicating degradation of the polymer, producing a final product material that was brittle when cooled, dusty when crushed, and could not be molded. Analysis of the mixed material by gel permeation chromatography (GPC) and differential scanning calorimetry (DSC) provided further evidence of degradation. The observed loss of desired polymer properties is consistent with the degradation of polymers proposed in US Pat. No. 2007/0029532 and the brittle foam formed in US Pat. No. 5,053,148.

Thus, simple phosphonic acid salts are not suitable for use in many polymers that are processed or subsequently exposed to high temperatures, such as 250°C, 260°C, 270°C or higher, since they undergo chemical transformation at such temperatures through processes , which damage the polymer. This can occur during compounding, for example in an extruder, or when salt is present in the polymer, in high temperature applications.

On the other hand, US Pat. No. 9,745,449 discloses that heating a phosphonic acid salt at a sufficiently high temperature, typically in the absence of other materials, thermally converts the salt into another, more thermally stable material that exhibits superior flame retardant activity when incorporated into polymer substrates. These thermally converted materials do not decompose at high temperatures and do not cause polymer degradation when processed in polymer compositions at elevated temperatures, for example, 240°C, 250°C, 260°C, 270°C or higher, which is a great advantage over previously known phosphonate salts, which exhibit flame retardant activity but often destroy the polymer during processing. These thermally converted materials are described as containing one or more compounds represented by empirical formula (IV):

where R is alkyl or aryl, M is a metal, q is a number from 1 to 7, such as 1, 2 or 3, r is a number from 0 to 5, such as 0, 1 or 2, often 0 or 1, y represents a number from 1 to 7, such as 1 to 4, and n represents 1 or 2, provided that 2(q)+r=n(y).

However, difficulties encountered when using the method and materials of US Pat. No. 9,745,449 include obtaining the product as a solid mass requiring crushing, grinding, or other such physical processing before use, the formation of mixtures of products containing water-soluble or thermally unstable compounds, and difficulties in controlling ratio of phosphorus and metal in the resulting product. In addition, examples from US patent US 9,745,449 describe the preparation of a phosphorus-containing flame retardant in several stages in which an intermediate metal salt of phosphonic acid is prepared, and then the dried salt is heated at temperatures above 200°C.

The present invention is directed to solve the above problems, as well as to obtain a phosphorus-containing flame retardant without the need to obtain or use an intermediate salt, as described in US patent US 9,745,449.

BRIEF DESCRIPTION OF THE INVENTION

In accordance with the present invention, a phosphorus-containing flame retardant is prepared by a process comprising reacting, at a reaction temperature, a mixture containing a metal or a suitable metal compound and a stoichiometric excess, relative to the metal or a suitable metal compound, of an unsubstituted or alkyl- or aryl-substituted phosphonic acid, wherein:

a metal is capable of forming a polycation (that is, a metal represented in its corresponding cationic form by the formula M ^(+)y , where M is a metal, (+)y is the charge of the metal cation, and y is 2 or greater) or a suitable metal compound , represented by the formula M _p ^(+)y X _q , where M is a metal, (+)y is the charge of a metal cation, y is 2 or greater, X is an anion, and the p and q values provide a neutrally charged metal compound;

molar ratio of unsubstituted or alkyl- or aryl-substituted phosphonic acid and metal or suitable metal compound in the mixture is greater than 4:1;

the reaction temperature is 105°C or higher; And

unsubstituted or alkyl- or aryl-substituted phosphonic acid is in a molten state at the reaction temperature.

Also disclosed is a method for producing a phosphorus-containing flame retardant, comprising reacting at a reaction temperature a mixture containing a metal or a suitable metal compound and a stoichiometric excess of an unsubstituted or alkyl- or aryl-substituted pyrophosphonic acid, wherein:

a metal is capable of forming a polycation (that is, a metal represented in its corresponding cationic form by the formula M ^(+)y as above) or a suitable metal compound represented by the formula M _p ^(+)y X _q where M is a metal, ( +)y represents the charge of the metal cation, y is 2 or greater, X is an anion, and the p and q values provide a neutrally charged metal compound;

a molar ratio of unsubstituted or alkyl- or aryl-substituted pyrophosphonic acid and metal or suitable metal compound in the mixture is greater than 2:1, and

unsubstituted or alkyl- or aryl-substituted pyrophosphonic acid is in a molten state at the reaction temperature.

In the process of the present invention, the unsubstituted or alkyl- or aryl-substituted phosphonic or pyrophosphonic acid used in stoichiometric excess as described herein acts as a reactant and solvent for the reaction. Often the reaction product is formed in the form of a suspension when the resulting flame retardant agent according to the present invention precipitates from the reaction mixture. Excess phosphonic or pyrophosphonic acid remaining after the reaction can be removed, along with any possible by-products, by filtration and/or washing, for example with water. In many embodiments, a substantially pure flame retardant agent is prepared, for example, a flame retardant agent containing primarily a single compound with flame retardant activity or a substantially mixture of active compounds. Conversion as metal or metal compounds is usually high and the product can be easily isolated and optionally further purified if desired.

The present method overcomes the difficulties observed in processes such as those in US Pat. No. 9,745,449 because, for example, production of water-soluble or thermally unstable compounds is reduced or prevented, and a fire-resistant product that typically crystallizes as a powder or fine particles can be produced directly in an easily processable form, that is, without the requirement or need for grinding, granulating or other such physical processing. Additionally, in many embodiments, the resulting flame retardant material produced in accordance with the present invention has a higher phosphorus to metal ratio than is observed with simple metal phosphonates, as further explained herein. High ratios of phosphorus to metal in the resulting flame retardant result in greater efficiency and therefore can tolerate lower levels when the flame retardant is mixed with thermoplastics.

Additional embodiments of the present invention include, but are not limited to, a process for producing a phosphorus-containing flame retardant, comprising reacting, at a reaction temperature, a metal or a suitable metal compound with a molar excess of an unsubstituted or alkyl or aryl substituted phosphonic acid, wherein the reaction temperature is about 150° C. or higher , the unsubstituted or alkyl- or aryl-substituted phosphonic acid is in a molten state at the reaction temperature, and the molar ratio of the unsubstituted or alkyl- or aryl-substituted phosphonic acid and the metal or suitable metal compound is greater than 4:1. In one embodiment, the reaction temperature ranges from about 150°C to about 300°C, such as from about 150°C to about 280°C, from about 160°C to about 260°C, or from about 160°C to about 220°C. In one embodiment, the molar ratio of unsubstituted or alkyl- or aryl-substituted phosphonic acid and metal or suitable metal compound ranges from about 5:1 to about 30:1. In one embodiment, a suitable metal compound is a metal oxide, halide, alkoxide, hydroxide, carboxylate or phosphonate. In one embodiment, a suitable metal compound is aluminum oxide, aluminum trichloride, aluminum trihydroxide or aluminum isopropoxide.

Other embodiments include, but are not limited to, a phosphorus-containing flame retardant prepared in accordance with the method described herein, a flame retardant polymer composition comprising (i) a polymer and (ii) a phosphorus-containing flame retardant according to the present invention, a method of improving the flame retardancy of a polymer by incorporating a flame retardant agent according to the present invention therein; and a method of incorporating a flame retardant composition containing the flame retardant agent according to the present invention into a polymer.

The foregoing brief description is not intended to limit in any way the scope of the claimed invention. In addition, it is to be understood that both the foregoing general description and the following detailed description are by way of example and illustration only and are not intended to limit the claimed invention.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows the result of thermogravimetric analysis (TGA) of an exemplary fire-retardant material obtained in accordance with Example 1 of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Unless otherwise indicated, the singular word used in this application means “one or more.”

The term "alkyl" as used herein includes "arylalkyl" unless the context otherwise requires.

The term "aryl" as used herein includes "alkylaryl" unless the context otherwise requires.

As used herein, the term “phosphonic acid” refers to an unsubstituted or alkyl- or aryl-substituted phosphonic acid unless the context otherwise requires.

As used herein, the term “pyrophosphonic acid” refers to unsubstituted or alkyl- or aryl-substituted pyrophosphonic acid unless the context otherwise requires.

As used herein, the term "stoichiometric excess" of an unsubstituted or alkyl- or aryl-substituted phosphonic or pyrophosphonic acid with respect to a metal or suitable metal compound refers to an amount of phosphonic or pyrophosphonic acid that exceeds the amount stoichiometrically required for the reaction between the metal or suitable metal compound and phosphonic or pyrophosphonic acid. The stoichiometric excess is typically represented by the molar ratio of the phosphonic or pyrophosphonic acid and the metal or suitable metal compound in the reaction mixture as described herein.

According to one aspect of the present invention, a metal or a suitable metal compound and a stoichiometric excess of an unsubstituted or alkyl- or aryl-substituted phosphonic acid are reacted to form a phosphorus-containing flame retardant. The reaction temperature is 105°C or higher, the phosphonic acid is in a molten state at the reaction temperature, and the molar ratio of the phosphonic acid and the metal or suitable metal compound in the reaction mixture is higher than 4:1. In this reaction, the metal is oxidized and can be represented in its corresponding cationic form by the formula M ^(+)y , where M represents the metal, (+)y represents the charge of the metal cation, and y is 2 or greater. A suitable metal compound can be represented by the formula M _p ^(+)y X _q where M is a metal, (+)y is the charge of a metal cation, y is 2 or greater, X is an anion, and the values for p and q provide neutrally charged metal compound.

In another aspect, a metal or a suitable metal compound as defined above and a stoichiometric excess of an unsubstituted or alkyl- or aryl-substituted pyrophosphonic acid are reacted to form a phosphorus-containing flame retardant. Pyrophosphonic acid is in a molten state at the reaction temperature, and the molar ratio of pyrophosphonic acid and metal or suitable metal compound in the reaction mixture is greater than 2:1.

In many embodiments, the molar ratio of phosphonic acid to metal or suitable metal compound in the reaction mixture is 5:1 or greater, such as about 6:1 or greater, about 8:1 or greater, or about 10:1 or greater. Higher molar excesses of phosphonic acid relative to the metal or suitable metal compound may be used in the reaction mixture, such as about 12:1 or higher, about 15:1 or higher, about 20:1 or higher, about 25:1 or higher, about 30:1 or higher, or anywhere in between. A large molar excess of phosphonic acid relative to the metal or suitable metal compound may be used. For example, the molar ratio can be up to about 50:1, up to about 100:1, up to about 300:1, up to about 500:1, or anywhere in between. However, as will be appreciated, the efficiency of the process may be compromised at certain large molar excesses, for example precipitation of the product from the reaction mixture may be difficult. In many embodiments, the molar ratio ranges from about 8:1, about 10:1, about 12:1, or about 16:1 to about 100:1 or up to about 50:1, such as about 10:1 , from about 15:1, or about 20:1 to about 50:1, or up to about 40:1.

In many embodiments, the molar ratio of pyrophosphonic acid to metal or suitable metal compound in the reaction mixture is 3:1 or greater, such as about 4:1 or greater, about 6:1 or greater, or about 8:1 or greater. Often higher molar excesses of pyrophosphonic acid to metal or suitable metal compound are used in the reaction mixture, such as about 10:1 or higher, about 12:1 or higher, about 15:1 or higher, about 18:1 or higher , about 20:1 or higher, or anywhere in between. A large molar excess of pyrophosphonic acid relative to the metal or suitable metal compound may be used. For example, the molar ratio can be up to about 30:1, up to about 50:1, up to about 100:1, up to about 250:1, or any range therebetween. However, as will be appreciated, the efficiency of the process may be compromised at certain large molar excesses, for example precipitation of the product from the reaction mixture may be difficult. In many embodiments, the molar ratio ranges from about 4:1, about 5:1, about 6:1, or about 8:1 to about 50:1 or up to about 25:1, such as about 5:1, about from 8:1, or about 10:1, to about 25:1, or up to about 20:1.

The reaction temperature for producing the phosphorus-containing flame retardant agent according to the present invention should be selected such that the phosphonic or pyrophosphonic acid is in a molten state at the reaction temperature. For example, phosphonic and pyrophosphonic acids (eg, alkyl-substituted phosphonic or pyrophosphonic acids) are often solid at room temperature (eg, methylphosphonic acid melts at about 105°C and ethylphosphonic acid melts at about 62°C) and thus heating phosphonic or pyrophosphonic acid, resulting in a liquefied physical state (i.e., molten state), is usually suitable for the formation of a homogeneous reaction mixture. As one skilled in the art will appreciate, the desired reaction temperature at which the phosphonic or pyrophosphonic acid is in a molten state may vary depending on the reagents selected and thermodynamic conditions.

The reaction temperature should also be selected to facilitate the formation of monoanionic and/or dianionic pyrophosphonic acid ligands in the reaction product. For phosphonic acid, a reaction temperature of 105°C or higher is used. Without being limited to any particular theory, the reaction temperature is selected to produce pyrophosphonic acid ligands via dehydration reaction(s). In many embodiments, the metal or suitable metal compound and the phosphonic acid are reacted at temperatures above 105°C, for example, about 115°C or higher, about 120°C or higher, about 130°C or higher, about 140°C or higher, about 150°C or higher, about 160°C or higher, about 170°C or higher, about 180°C or higher, about 200°C or higher, about 220°C or higher, about 240°C or higher, about 260°C or higher, about 280°C or higher, or any range in between. The reaction temperature may be higher than those previously described, such as up to about 350° C., up to about 400° C. or higher, but generally does not match or exceed the boiling point of the phosphonic acid. For example, the reaction temperature may range from about 150°C to about 300°C, such as from about 150°C to about 280°C, from about 160°C to about 260°C, or from about 160°C to about 240°C WITH. In many embodiments, the reaction temperature ranges from about 110°C to about 350°C, from about 115°C to about 300°C, from about 125°C to about 280°C, or from about 140°C to about 260°C . The dehydration reaction(s) produces water, which can potentially lead to an undesirable reverse reaction (hydrolysis). Therefore, in some embodiments, the reaction system is designed to facilitate removal, such as continuous removal, of water from the reaction. For example, the reaction temperature may be selected above the boiling point of water to the extent necessary to boil off at least a portion or a desired amount (eg, most, substantially all, or all) of the water from the reaction. Additional means, such as gas purge, vacuum and/or other known means, can be used to facilitate the removal of water from the reaction system.

Since dehydration is not required for pyrophosphonic acid, the reaction temperature for pyrophosphonic acid can be lower than that described above for phosphonic acid. Generally, the limiting criterion for selecting a suitable reaction temperature when using pyrophosphonic acid is the requirement that the pyrophosphonic acid be in a molten state at the reaction temperature. Often the metal or a suitable metal compound and the pyrophosphonic acid are reacted at a temperature of 20° C. or higher. In many embodiments, the metal or a suitable metal compound and the pyrophosphonic acid are reacted at temperatures above 20°C, such as about 40°C or higher, about 60°C or higher, about 80°C or higher, about 100°C or higher, about 140°C or higher, about 180°C or higher, about 200°C or higher, or any range therebetween. The reaction temperature may be higher than those previously described, such as up to about 300° C., up to about 400° C. or higher, but generally does not correspond to or exceed the boiling point of pyrophosphonic acid. In many embodiments, the reaction temperature ranges from about 25°C to about 350°C, from about 25°C to about 280°C, from about 30°C to about 260°C, from about 40°C to about 260°C , from about 60°C to about 260°C, from about 80°C to about 240°C, from about 100°C to about 240°C, from about 110°C to about 240°C, or from about 120°C up to approximately 240°C. Depending, for example, on the metal compound used to react with the pyrophosphonic acid, the reaction may produce water. As described above, in some embodiments, the reaction system is designed to facilitate removal, such as continuous removal, of water from the reaction. For example, the reaction temperature may be selected above the boiling point of water to the extent necessary to boil off at least a portion or a desired amount (eg, most, substantially all, or all) of the water from the reaction. Additional means, such as gas purge, vacuum and/or other known means, can be used to facilitate the removal of water from the reaction system.

Often, as the reaction proceeds, the product forms as a suspension as the resulting fire retardant product precipitates from the reaction product mixture. Thus, the reaction usually proceeds for a time sufficient to achieve such precipitation. Generally, the amount of time required to achieve at least significant conversion to a fire-resistant product, expressed as a metal or suitable metal compound, will depend on the reaction temperature, with higher temperatures generally resulting in shorter reaction times. In many embodiments, the metal or suitable metal compound and the phosphonic or pyrophosphonic acid are heated at the reaction temperature for from about 0.1 to about 48 hours, such as from about 0.2 to about 36 hours, from about 0.5 to about 30 hours, from about 1 hour to about 24 hours, for example, from about 1 hour to about 12 hours, from about 1 hour to about 8 hours, or from about 2 hours to about 5 hours, although other lengths of time may be used.

The metal or suitable metal compound and a molar excess of phosphonic or pyrophosphonic acid can be combined in any manner suitable to form a reaction mixture. For example, a phosphonic or pyrophosphonic acid and a metal or metal compound may be mixed (eg, stirred) together, for example, to form a homogeneous reaction mixture. In some embodiments, a metal or suitable metal compound is added to a phosphonic or pyrophosphonic acid that has been preheated to reaction temperature. In some embodiments, the phosphonic or pyrophosphonic acid is preheated and melt-stirred, for example, under a nitrogen atmosphere or reduced pressure/vacuum. In other embodiments, the metal or metal compound is added as quickly as possible without causing a large change in the reaction temperature due to the exothermic nature of the reaction. In some embodiments, a phosphonic or pyrophosphonic acid and a metal or suitable metal compound are combined without preheating the phosphonic acid or without sufficient heating to liquefy the phosphonic or pyrophosphonic acid, and then the components are heated to reaction temperature. The entire amount of the metal or suitable metal compound or phosphonic or pyrophosphonic acid may be added to the reaction all at once or in portions. No additional solvents are required since the phosphonic or pyrophosphonic acid used in molar excess acts as a reagent and solvent, but additional solvent can be used if desired. In some embodiments, additional solvent is used when using molar ratios of phosphonic or pyrophosphonic acid and metal or suitable metal compound that are at or near the lower end of the molar ratios described herein.

In some embodiments, after the desired conversion is achieved, such as complete or substantially complete conversion to a flame retardant product, the product reaction mixture is cooled to a temperature above or below the melting point of the excess phosphonic or pyrophosphonic acid to retain the excess phosphonic or pyrophosphonic acid. liquid acids. Excess phosphonic or pyrophosphonic acid can be removed by filtration/washing and regenerated if desired. The recovered excess phosphonic or pyrophosphonic acid can be recycled, for example, back to a reactor in which the metal or suitable metal compound is reacted with the phosphonic or pyrophosphonic acid. Once converted to the reaction product, a solvent, such as water, alcohol, and/or other suitable (eg, polar) liquid, may optionally be added to dissolve or otherwise help remove excess phosphonic or pyrophosphonic acid. The fire retardant product is often isolated by filtration, optionally followed by additional processing (eg washing, drying, sifting, etc.). The resulting flame retardant product, which is typically in powder or fine particle form, is easily processed, that is, without the requirement or need for crushing, milling or other such physical processing prior to use. It should be understood that obtaining the flame retardant material "directly" in powder or fine particle form in accordance with the method disclosed herein allows for treatment of the reaction product, such as isolating the flame retardant product (e.g., separating the flame retardant product from excess phosphonic or pyrophosphonic acid or remaining solvent) such that may include, for example, treating the reaction product by filtering, sieving, washing, drying, and the like. After the reaction, the resulting reaction product mixture, often a slurry, can be cooled to or just above the melting point of the excess phosphonic acid, and the slurry can be combined with water. The water/slurry mixture can be stirred as needed to break up any large lumps that may have formed. The solid product can be isolated by filtration, optionally washed with water and dried to obtain the product in powder or fine particle form. In some cases, the product may be sieved to reduce particle size.

The method of the present invention provides a flame retardant agent containing one or more metals and one or more mono- and/or bidentate pyrophosphonic acid ligands. In some embodiments, compounds may be prepared that further contain phosphonate ligands, but in all embodiments, compounds containing a monoanionic pyrophosphonic acid ligand and/or a dianionic pyrophosphonic acid ligand are obtained.

This method can produce mixtures of fire retardant compounds, but in many embodiments the method produces the fire retardant material in the form of one or predominantly one compound with a high degree of conversion on a metal or metal compound basis, such as, for example, a conversion of at least 70%, 80 %, 85%, 90%, 95%, 98% or higher, or any range therebetween, as opposed to mixtures of compounds that are prepared by prior art methods involving heat treatment of metal phosphonate salts. In a general embodiment, in which phosphonate ligands may be present in the flame retardant product, the reaction typically proceeds as shown:

where M represents a metal cation and (+)y represents the charge of that cation, for example, M represents a di-, tri-, tetra-, pentacationic metal, X represents the anionic ligand or ligands attached to the metal, and the stoichiometric ratio of M and X (i.e., p and q) provides a neutrally charged compound, R is H, alkyl, aryl, alkylaryl, or arylalkyl, and a, b, c, and d represent the ratio of the components to which they correspond relative to each other in the reaction product , and y, a, b, c and d have values that provide a neutrally charged product, provided that y is 2 or greater and only one of a or c can be 0 (often c is not zero). In some embodiments, the above d-factor phosphonic acid ligand, if present, may be present as a dianion. In many embodiments, d is 0.

In another aspect, the flame retardant product prepared in accordance with the present invention, usually in the form of a powder or fine particles, contains a compound or mixture of various compounds of empirical formula (II)

where R represents an H, alkyl, aryl, alkylaryl or arylalkyl group, a, b, c and d represent the ratio of the components to which they correspond relative to each other in the compound, and a is usually a number from 0 to 8, for example, 0 to 6, 0 to 4 or 0 to 2, c is usually a number from 0 to 10, for example 0 to 8, 0 to 6, 0 to 4 or 0 to 2, d is usually a number from 0 to 6, such as 0 to 4 or 0 to 2, M represents a metal, y represents a number from 2 to 5, such as 2, 3 or 4, often 2 or 3, and M ^{(+) y} represents a metal cation, where (+)y represents the charge formally assigned to the cation. The values of a, b, c, d, and y may vary but will satisfy the charge balance equation 2(a)+c+d=b(y), and only one of a or c may be 0. In many embodiments, c not equal to zero. In cases where a dianionic phosphonic acid ligand is present in the compound, the charge balance equation takes the form 2(a)+c+d+2(d)=b(y). The value of b is limited only in that it must satisfy the previous equations, but in many embodiments, b is a number from 1 to 4, such as 1 or 2. In some embodiments, a is 0, 1, or 2 (for example, 0 or 1 ), c is 1 or 2, ad is 0, 1 or 2 (eg 0 or 1), and the product is neutrally charged.

In many embodiments, d is 0, as in:

where R, M, y, a, b and c are as described above, and the charge balance equation for the product becomes 2(a)+c=b(y).

Often in the above formulas (II) and (III), c is not equal to zero (for example, c is 1 to 10, 1 to 8, 1 to 6, 1 to 4, or 1 or 2).

In accordance with the method disclosed herein, in many embodiments, for example, when using dicationic or tricationic metals, it has surprisingly been found that a flame retardant compound is obtained where in the above formulas c is not equal to zero and the product has a more favorable ratio of phosphorus atoms and metal atoms (ie, P and M) to provide flame retardancy compared to phosphorus-containing flame retardants described in the art. For example, tricationic metals (eg aluminum) and dicationic metals (eg zinc) are known to form tricationic and disubstituted charge-neutral compounds, respectively. As can be seen from the prior art, trisphosphonate aluminum salts having a 3:1 ratio of phosphorus to aluminum and diphosphonate zinc salts having a 2:1 ratio of phosphorus to zinc are known as flame retardants. However, according to the formation of the pyrophosphonic acid ligand according to the present invention, and in particular when c in the above formulas is not zero, the ratio of phosphorus to metal in the flame retardant product is higher. For example, as shown in the examples herein, when using the method of the present invention, the ratio of phosphorus to aluminum or the ratio of phosphorus to iron in the resulting flame retardant product was 4:1. This higher phosphorus to metal ratio results in high efficiency and may allow lower levels when blended with thermoplastic polymers.

In some specific embodiments, y in formula (III) is 2 (that is, M ^(+)y is a dicationic metal such as described herein), a is 0, b is 1, and c is 2. In some embodiments In embodiments, the dicationic metal M is magnesium (Mg), calcium (Ca) or zinc (Zn). In other embodiments, y in formula (III) is 3 (that is, M ^(+)y is a tricationic metal such as described herein), a is 1, b is 1, and c is 1. In some embodiments the trication metal M is selected from aluminum (Al), gallium (Ga), antimony (Sb), iron (Fe), cobalt (Co), boron (B) and bismuth (Bi). In some embodiments, the tricationic metal M is Al, Fe, Ga, Sb, or B.

As is usually the case with inorganic coordination compounds, the reaction product in the reaction described above and the compounds of empirical formulas (II) and (III) are idealized, so that the reaction product or compounds may include coordination polymers, complex salts, salts in which certain atomic valences are common, etc.

For example, in many embodiments, empirical formula (II) or (III) represents a monomeric structural unit (ie, coordination unit) of a coordination polymer, wherein the flame retardant compound of the present invention forms an extended structure of the coordination polymer.

In one example, where M is Al and y is 3, the compound of empirical formula (III) is prepared according to the following empirical formula (IIIa):

(IIIa).

As shown herein, the absence of subscripts a, b, and c in the empirical formulas indicates that each subscript is 1, indicating a component ratio of 1:1:1 (which in the case of empirical formula (IIIa) is the dianionic ligand ratio pyrophosphonic acid, metal atom and monoanionic ligand of pyrophosphonic acid, making up 1:1:1). In this example, the empirical formula (IIIa) represents a repeating monomer structural unit (ie, a coordination unit) of a coordination polymer, so that the flame retardant compound of the present invention forms an extended structure of the coordination polymer.

Often, the compound of empirical formula (II) or (III), which in many embodiments is an extended coordination polymer as described herein, constitutes all, substantially all, or at least a major portion of the flame retardant product, such as at least 75 %, 85%, 90%, 95%, 98% by weight or greater of the flame retardant product, or any range in between.

The compound of empirical formula (II) or (III) (for example, (IIIa)) can be obtained with a high degree of conversion in terms of metal or metal compound, such as a degree of conversion of at least 70%, 80%, 85% , 90%, 95%, 98% or higher, for example, a conversion rate of at least 70 to 95%. In some of these embodiments, M is aluminum (that is, the reaction product is produced using aluminum or one or more aluminum compounds such as those described herein) or iron (that is, the reaction product is prepared using iron or one or more iron compounds, such as those described herein).

The phosphonic acid used in the present method may be represented by formula (I).

where R represents H, alkyl, aryl, alkylaryl or arylalkyl. In many embodiments, R is H, alkyl of 1-12 carbon atoms, aryl of 6-10 carbon atoms, C _7-18 alkylaryl, or C _7-18 arylalkyl, wherein said alkyl, aryl, alkylaryl, or arylalkyl is unsubstituted or substituted halogen, hydroxyl, amino group, alkylamine with 1-4 carbon atoms, di-C _1-4 -alkylamine, alkoxyl with 1-4 carbon atoms, carboxyl or alkoxycarbonyl with 2-5 carbon atoms in the alkoxyl. In some embodiments, said alkyl, aryl, alkylaryl, or arylalkyl is an unsubstituted 1-12 carbon alkyl, 6-carbon aryl, C _7-10 alkylaryl, or C _7-10 arylalkyl, such as 1-6 alkyl carbon atoms, phenyl or C _7-9 -alkylaryl. In some embodiments, R is substituted or unsubstituted C1-C6 alkyl, C6-aryl, _C7-10 -alkylaryl, or _C7-12- arylalkyl, e.g., C1-4C alkyl, C6-aryl 6 carbon atoms, C _7-9 -alkylaryl or C _7-10 -arylalkyl. In many embodiments, R is an unsubstituted alkyl of 1-12 carbon atoms, such as alkyl of 1-6 carbon atoms. In many embodiments, lower alkylphosphonic acids are used, such as methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, and the like.

R as alkyl may be a straight or branched chain alkyl group having a specified number of carbon atoms and includes, for example, straight alkyls such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl , undecyl, dodecyl, and branched alkyl such as isopropyl, isobutyl, sec-butyl, tert-butyl, ethylhexyl, tretoctyl and the like. For example, R as alkyl can be selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl and tert-butyl. In many embodiments, R is methyl, ethyl, propyl, or isopropyl, such as methyl or ethyl.

Often, when R is aryl, it is phenyl. Examples of R as alkylaryl include phenyl substituted with one or more alkyl groups, for example, groups selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl and the like. Examples of R as arylalkyl include, for example, benzyl, phenethyl, styryl, cumyl, phenpropyl and the like.

In many embodiments, R is selected from methyl, ethyl, propyl, isopropyl, butyl, phenyl, and benzyl.

The pyrophosphonic acid used in the present method can be represented by formula (Ia):

where R has the same meanings as described above for formula (I).

The general reaction scheme with pyrophosphonic acid and a suitable metal compound can be represented as:

where R, M, X, p, q, y, a, b and c have the meanings described herein.

More than one phosphonic acid, more than one pyrophosphonic acid, or a combination of phosphonic and pyrophosphonic acids can be used in the process of the present invention, provided that the mixture of phosphonic acids and/or pyrophosphonic acids is in a molten state at the reaction temperature. In some embodiments, the phosphonic acid or pyrophosphonic acid is produced in situ. For example, phosphonic or pyrophosphonic acid can be obtained, for example, by hydrolysis of starting materials of higher oligomers of phosphonic acid and/or cyclic phosphonic acid anhydride.

As used herein, the term "suitable metal compound" and the like refer to a compound of the formula M _p ^(+)y X _q where M is a metal capable of forming a polycation, for example a metal that forms a 2+, 3+, 4+ or 5+ is typically 2+, 3+ or 4+, and X is any anion that provides a neutrally charged compound with metal M. Suitable examples for X include, but are not limited to, anions that form oxides with metal M , halides, alkoxides, hydroxides, carbonates, carboxylates and phosphonates. The values for p and q provide a neutrally charged metal compound, such as aluminum oxide, Al ₂ O ₃ . In some embodiments, an unsubstituted metal M is used, as described herein. Examples of suitable metals (M) include, but are not limited to, Mg, Ca, Ba, Zn, Zr, Ge, B, Al, Si, Ti, Cu, Fe, Co, Ga, Bi, Mn, Sn or Sb. In some embodiments, M is selected from Mg, Ca, Ba, Zn, Zr, Ga, B, Al, Si, Ti, Cu, Fe, Sn or Sb. In some embodiments, M is selected from Mg, Ca, Ba, Zn, Zr, B, Al, Si, Ti, Fe, Sn or Sb, for example, M can be Mg, Zn, Ca, Fe or Al.

Suitable metal compounds include, but are not limited to, those having a metal-oxygen bond, a metal-nitrogen bond, a metal-halogen bond, a metal-hydrogen bond, a metal-phosphorus bond, a metal-sulfur bond, a metal-boron bond, etc. etc., for example, oxides, halides, alkoxides, hydroxides, carboxylates, carbonates, phosphonates, phosphinates, phosphonites, phosphates, phosphites, nitrates, nitrites, borates, hydrides, sulfonates, sulfates, sulfides, etc. Mg, Ca, Ba, Zn, Zr, Ge, B, Al, Si, Ti, Cu, Fe, Co, Ga, Bi, Mn, Sn or Sb, for example oxides, hydroxides, halides or alkoxides of Mg, Ca, Ba , Zn, Zr, Ga, B, Al, Si, Ti, Cu, Fe, Sn or Sb, such as oxides, hydroxides, halides or alkoxides of Mg, Ca, Ba, Zn, Zr, B, Al, Si, Ti , Fe, Sn or Sb, for example oxides, hydroxides, halides or alkoxides of Mg, Zn, Ca, Fe or Al.

In some embodiments, the metal M of the metal or suitable metal compound is aluminum or iron. In some embodiments, a suitable metal compound is selected from aluminum halides, oxides, hydroxides, alkoxides, carbonates, carboxylates and phosphonates. In some embodiments, a suitable metal compound is selected from aluminum halides, oxides, hydroxides and alkoxides. In some embodiments, a suitable metal compound is selected from aluminum oxide, aluminum trichloride, aluminum trihydroxide, aluminum isopropoxide, aluminum carbonate, and aluminum acetate. In other embodiments, a suitable metal compound is selected from iron halides, oxides, alkoxides, carbonates and acetates. In some embodiments, a suitable metal compound is selected from iron(III) oxide, iron(III) chloride, iron(III) isopropoxide, and iron(III) acetate.

In some embodiments, R is methyl, ethyl, propyl, isopropyl, or butyl and M is Al, Fe, Zn, or Ca. In other embodiments, X is oxygen, hydroxyl, alkoxy, or halogen.

The reaction described herein can, but does not necessarily, occur under reduced pressure or vacuum.

The reaction product mixture formed by the reaction described herein, often presented as a slurry, can be combined with a liquid (eg, water) and stirred as desired to break up any lumps that may have formed. The solid product can be isolated by filtration, optionally washed and dried to obtain the product in powder or fine particle form. In some cases, the product may be sieved to reduce particle size.

The reaction described herein can, if desired, be promoted using seed material. For example, the use of a seed material can reduce the time to achieve conversion to a flame retardant product and can result in increased consistency in the physical characteristics of the product. Often, the seed material is added to the reaction mixture while heating or after heating to the reaction temperature. In some embodiments, the seed material includes a flame retardant material prepared in accordance with the method of the present invention, such as a flame retardant compound of empirical formula (II), (III) or (IIIa), as described herein. The seed material can be selected or ground to the desired particle size.

In some embodiments, the suitable metal compound is aluminum oxide, and the flame retardant material is prepared as follows:

In one example, a phosphonic acid, such as C ₁ -C ₁₂ -alkylphosphonic acid (for example, methyl, ethyl, propyl, isopropyl, butyl or tert-butylphosphonic acid) is heated to or above its melting point, 105°C, as for example, up to 115°C, 125°C, 140°C, 150°C, 160°C, 180°C, 200°C, 220°C or 240°C or higher, with stirring (for example, under nitrogen atmosphere) when melting. An aluminum oxide, hydroxide, halide, alkoxide, carbonate or carboxylate, such as aluminum oxide, aluminum trichloride, aluminum trihydroxide, aluminum isopropoxide, aluminum carbonate or aluminum acetate, is added with stirring at a stoichiometric excess of phosphonic acid, such as the molar ratio of phosphonic acid and metal compounds as described herein, for example, 5:1 or higher, 10:1 or higher, or 15:1 or higher. Typically, a slurry is formed as the reaction proceeds, and the solid product of the flame retardant can be separated, for example, by filtration, washing, etc., to obtain the product in the form of a powder or fine particles. Prior to isolation of the solid product, further processing of the product reaction mixture may be performed, such as cooling the product reaction mixture to a temperature above or below the melting point of the excess phosphonic acid and combining with a liquid, such as water, and optionally stirring as described above. The solid fire retardant product can be isolated by filtration, washed with additional solvent if desired, and dried to obtain a powder or fine particulate product. The fire retardant product contains phosphorus and aluminum in a 4:1 ratio according to the following empirical formula:

In another example, the example described immediately above is carried out using iron or a suitable iron compound such as iron halides, oxides, alkoxides, carbonates or acetates, for example iron(III) oxide, iron(III) chloride, iron(III) isopropoxide or iron(III) acetate. This fire retardant product contains phosphorus and iron in a 4:1 ratio according to the following empirical formula:

Often, the compound of the above empirical formulas (which in many embodiments is an extended coordination polymer as described herein) constitutes all, substantially all, or at least a major portion of the flame retardant product, such as at least 75%, 85% , 90%, 95%, 98% by weight of the fire resistant product or higher, or any range in between.

In some embodiments, the suitable metal compound is a metal phosphonate salt. The metal in this metal phosphonate salt may be metal M, as described herein. A suitable metal compound may be a metal phosphonate salt of the following formula:

where R and M have the meanings as described above, p is a number from 2 to 5, such as 2, 3 or 4, and y is a number from 2 to 5,

for example, 2, 3 or 4, so that M(+)y represents a metal cation, where (+)y represents the charge formally assigned to the cation. Typically, a metal phosphonate salt has a neutral charge (that is, p=y). The metal phosphonate salt can be prepared by methods known in the art.

In some embodiments, a metal phosphonate salt is prepared by reacting the parent metal compound and phosphonic acid with a solvent (eg, water) for the phosphonic acid. The starting metal compound may be a compound corresponding to a suitable metal compound described herein. In some embodiments, the parent metal compound and the phosphonic acid are reacted at a temperature at or near room temperature, or at a temperature ranging from about 0 to about 20°C. The resulting metal phosphonate salt can then be used as a suitable metal compound in accordance with the method of the present invention.

For example, a phosphonic acid, such as an alkylphosphonic acid, eg methyl, ethyl, propyl, isopropyl, butyl or tert-butylphosphonic acid, and a solvent (eg water) can be mixed to form a homogeneous solution. Any convenient ratio of water to phosphonic acid can be used, for example 10:1 to 1:10 by weight, more typically 5:1 to 1:5, and good results have been achieved using mixtures of 2:1 to 1: 2. This solution may be cooled, for example, to a range of from about 0 to about 20° C., and a parent metal compound, such as a metal oxide, halide, alkoxide, or hydroxide, is added to react with the phosphonic acid. A metal phosphonate salt is formed, which is then used as a suitable metal compound in accordance with the method described herein. For example, in a separate reactor, a molar excess of phosphonic acid as described herein (e.g., a 5:1 molar ratio of phosphonic acid to metal phosphonate salt) is preheated to a molten state and reacted with the metal phosphonate salt to form a flame retardant product . In embodiments including an aluminum phosphonate salt as a suitable metal compound, the flame retardant product contains phosphorus and aluminum in a 4:1 ratio of phosphorus to aluminum according to the following rule of thumb:

Often, the compound of this empirical formula (which in many embodiments is an extended coordination polymer as described herein) constitutes all, substantially all, or at least a major portion of the flame retardant product, such as at least 75%, 85%, 90 %, 95%, 98% by weight of the fire resistant product or higher, or any range in between.

The flame retardant agent of the present invention can be used in conjunction with a variety of other flame retardants and/or flame retardant synergists or adjuvants that are known in the art. For example, the flame retardant agent of the invention may be formulated with one or more materials selected from: carbon black, graphite, carbon nanotubes, siloxanes, polysiloxanes, polyphenylene ether (PPE), phosphine oxides and polyphosphine oxides, for example benzylphosphine oxides, polybenzylphosphine oxides and the like. similar; melamine, melamine derivatives and melamine condensation products, melamine salts such as, but not limited to, melamine cyanurate, melamine borate, melamine phosphates, melamine metal phosphates, melam, melem, melon and the like; inorganic compounds including clays, metal salts such as hydroxides, oxides, oxide hydrates, borates, carbonates, sulfates, phosphates, phosphites, hypophosphites, silicates, mixed metal salts, etc., such as talc and other magnesium silicates, silicate calcium, aluminosilicate, hollow tube aluminosilicate (DRAGONITE), calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, HALLOYSITE or boron phosphate, calcium molybdate, expanded vermiculite, zinc stannate, zinc hydroxystannate, zinc sulfide and zinc borate, zinc molybdate (or complexes thereof, e.g. Kemgard 911B), calcium molybdate/magnesium hydroxide complex (e.g. Kemgard MZM), zinc molybdate/magnesium silicate complex (e.g. Kemgard 911C), calcium molybdate/zinc complex (e.g. Kemgard 911A), phosphate zinc (or its complexes, e.g. Kemgard 981), magnesium oxide or hydroxide, aluminum oxide, alumina hydroxide (boehmite), aluminum trihydrate, silicon dioxide, tin oxide, antimony (III and V) oxide and oxide hydrate, titanium oxide and zinc oxide or oxide hydrate, zirconium oxide and/or zirconium hydroxide, and the like.

Unless otherwise specified, as used herein, the term "phosphate" when used as a component in a "phosphate salt" such as metal phosphate, melamine phosphate, metal melamine phosphate, etc., refers to phosphate, hydrogen phosphate, dihydrogen phosphate, pyrophosphate, polyphosphate or anion or polyanion of condensation products of phosphoric acid.

Likewise, unless otherwise specified, as used herein, the term "phosphite" when used as a component in a "phosphite salt" such as metal phosphite, etc., refers to phosphite or hydrophosphite.

The flame retardant of the present invention may also be formulated with other flame retardants, such as halogenated flame retardants, alkyl or arylphosphine oxide flame retardants, alkyl or aryl phosphate flame retardants, alkyl or aryl phosphonates, alkyl or aryl phosphinates, and alkyl or aryl phosphinates. arylphosphinic acid. In some embodiments, the flame retardant agent comprises a mixture of a flame retardant agent in accordance with the present invention and a phosphine salt of the following formula (for example, aluminum tris(dialkylphosphinate),

R ₁ and R ₂ can each independently be a group corresponding to R as described herein, M is a metal as described herein (for example, Al or Ca), and n is a number from 2 to 7, for example, from 2 to 4, often 2 or 3.

In many embodiments, the flame retardant polymer composition of the present invention comprises (i) a polymer, (ii) a flame retardant material of the present invention, and (iii) one or more additional flame retardants and/or one or more flame retardant synergists or adjuvants.

For example, in some embodiments, the flame retardant polymer composition contains one or more additional flame retardants, e.g., halogenated flame retardants, phosphine oxide flame retardants, alkyl or aryl phosphonates, or salts of alkyl or aryl phosphinates, e.g., aluminum tris(dialkylphosphinate), such as tris( diethylphosphinate) aluminum.

In some embodiments, the flame retardant polymer composition contains one or more flame retardant synergists or adjuvants, such as melamine, melamine derivatives and melamine condensation products (e.g., melam, melem, melon), melamine salts, phosphine oxides and polyphosphine oxides, metal salts such as hydroxides , oxides, oxide hydrates, borates, phosphates, phosphonates, phosphites, silicates and the like, for example, aluminum hydrophosphite, melem or melamine metal phosphate, for example, melamine metal phosphate, where the metal includes aluminum, magnesium or zinc. In specific embodiments, the one or more additional flame retardants, synergists, or flame retardant adjuvants include aluminum tris(dialkylphosphinate), aluminum hydrophosphite, methylene diphenylphosphine oxide-substituted polyaryl ether, xylene bis(diphenylphosphine oxide), 4,4-bis(diphenylphosphinylmethyl)-1,1' -biphenyl, ethylenebis-1,2-bis(9,10-dihydro-9-hydroxy-10-phosphaphenanthrene-10-oxide)ethane, melem, melam, melon or dimelamine zinc pyrophosphate.

Some embodiments provide a halogen-free polymer composition. In such embodiments, halogen-containing flame retardants or synergists will be eliminated to the greatest extent possible.

The flame retardant material of the present invention can be combined with an additional flame retardant agent, synergist or adjuvant in the range of 100:1 to 1:100 by weight of the flame retardant agent of the invention relative to the total weight of the additional flame retardant agent, synergist and/or adjuvant. In some embodiments, the flame retardant material of the present invention is present in the range of 10:1 to 1:10 by weight of the flame retardant material of the invention relative to the total weight of the additional flame retardant, synergist, and/or adjuvant, for example, weight ratios ranging from 7:1 to 1 :7, 6:1 to 1:6, 4:1 to 1:4, 3:1 to 1:3 and 2:1 to 1:2. The flame retardant of the invention is often the main component in such a combination, for example in a ratio of 10:1 to 1.2:1 or 7:1 to 2:1 by weight of the flame retardant of the invention relative to the total weight of the additional flame retardant, synergist and /or adjuvant, but the material according to the invention can also be a minor component of the mixture, for example in a ratio of 1:10 to 1:1.2 or 1:7 to 1:2.

The thermally stable high temperature flame retardant of the present invention can be mixed with thermoplastic resins such as high temperature polyamides and polyterephthalate esters without decomposition or adversely affecting the physical properties of the polymer, and the flame retardant activity is excellent. The flame retardant agent according to the invention can be used in other polymers, with other synergists and with conventional polymer additives.

The polymer of the flame retardant composition according to the present invention can be any polymer known in the art, such as homopolymers and copolymers of polyolefins, rubbers, polyesters, including polyalkylene terephthalates, epoxy resins, polyurethanes, polysulfones, polyimides, polyphenylene ethers, styrene polymers and copolymers , polycarbonates, acrylic polymers, polyamides, polyacetals and biodegradable polymers. Blends of various polymers, such as polyphenylene ether/styrene resin, polyvinyl chloride/acrylonitrile, butadiene and styrene (ABS) blends, or other modified impact polymers such as methacrylonitrile and α-methylethyrene containing ABS, and polyester/ABS or polycarbonate /ABS and polyester or polystyrene, as well as some other impact modifiers can also be used. Such polymers are commercially available or prepared by methods well known in the art.

The flame retardant agent of the present invention is particularly useful in thermoplastic polymers that are processed and/or used at high temperatures, for example, styrene polymers, including high impact polystyrene (HIPS), polyolefins, polyesters, polycarbonates, polyamides, polyurethanes, polyphenylene ethers and the like. similar.

For example, the polymer may be a polyester resin, a styrene resin, a polyamide resin, a polycarbonate resin, a polyphenylene oxide resin, a vinyl resin, an olefin resin, an acrylic resin, an epoxy resin, or a polyurethane. This polymer may be a thermoplastic or thermoset resin and may be reinforced, such as glass fiber reinforced. In some embodiments, the polymer is a thermoplastic polyurethane. In some embodiments, the polymer is a thermosetting epoxy resin. More than one polymer resin may be present. In specific embodiments, the polymer is an engineering polymer, such as a thermoplastic or reinforced thermoplastic polymer, such as a glass fiber reinforced thermoplastic polymer, such as an optionally glass-filled polyester, epoxy resin, or polyamide, such as a glass-filled polyester, such such as glass-filled polyalkylene terephthalate, or glass-filled polyamide.

Polyester resins include homopolyesters and copolyesters made, for example, by the polycondensation of a dicarboxylic acid component and a diol component and the polycondensation of a hydroxycarboxylic acid or lactone component, for example, an aromatic saturated polyester resin such as polybutylene terephthalate or polyethylene terephthalate.

Resins from the polyamide (PA) series include polyamides derived from a diamine and a dicarboxylic acid, polyamides derived from an aminocarboxylic acid, optionally in combination with a diamine and/or dicarboxylic acid, and polyamides derived from a lactam, optionally in combination with a diamine and/or dicarboxylic acid. /or dicarboxylic acid. The polyamide also includes a copolyamide made from at least two different types of constituent polyamide components. Examples of polyamide resins include aliphatic polyamides such as PA 46, PA 6, PA 66, PA 610, PA 612, PA 11 and PA 12, polyamides derived from an aromatic dicarboxylic acid, such as terephthalic acid and/or isophthalic acid, and an aliphatic diamine, for example, hexamethylenediamine or nonamethylenediamine, and polyamides derived from both aromatic and aliphatic dicarboxylic acids, for example, both terephthalic acid and adipic acid, and an aliphatic diamine, for example, hexamethylenediamine, and others. These polyamides can be used individually or in combination. In some embodiments, the polymer contains PA 6. In some embodiments, the polymer contains PA 66. In some embodiments, the polymer contains polyphthalamide.

Polyamides with melting points of at least 280°C are widely used for the production of molding compositions, which make it possible to produce molded products, for example, for the electrical and electronics industry, with excellent dimensional stability at high temperatures and very good flame retardant properties. Molding compositions of this type are in demand, for example, in the electronics industry for the production of components that are mounted on printed circuit boards in accordance with the so-called surface mounting technology, SMT (surface mounting technology). In this application, these components must withstand temperatures up to 270°C for short periods of time without changing dimensions.

Such high temperature polyamides include certain polyamides derived from alkyl diamines and diacids, such as polyamide 4,6, however many high temperature polyamides are aromatic and semi-aromatic polyamides, that is, homopolymers, copolymers, terpolymers or higher order polymers that are derived from monomers containing aromatic groups. A single aromatic or semi-aromatic polyamide may be used, or mixtures of aromatic and/or semi-aromatic polyamides may be used. It is also possible for the above polyamides and polyamide blends to be blended with other polymers, including aliphatic polyamides.

Examples of these high temperature aromatic or semi-aromatic polyamides include polyamide 4T, poly(m-xylylene adipamide) (polyamide MXD,6), poly(dodecamethylene terephthalamide) (polyamide 12,T), poly(decamethylene terephthalamide) (polyamide 10,T), poly(nonamethylene terephthalamide) (polyamide 9,T), hexamethylene adipamide/hexamethylene terephthalamide copolyamide (polyamide 6,T/6,6), hexamethylene terephthalamide/2-methylpentamethylene terephthalamide copolyamide (polyamide 6,T/D,T), hexamethylene terephthalamide/hexamethylene terephthalamide/hexamethylene isophthalamide copolyamide yes (polyamide 6, 6/6,T/6,I), poly(caprolactamhexamethylene terephthalamide) (polyamide 6/6,T), hexamethylene terephthalamide/hexamethylene isophthalamide copolymer (6,T/6,I), and the like.

Thus, certain embodiments of the present invention are compositions containing a polyamide that melts at high temperatures, for example, 280°C or higher, 300°C or higher, in some embodiments, 320°C or higher, for example, 280 to 340°C, such as polyamide 4,6 and aromatic and semi-aromatic polyamide described above, articles containing high temperature polyamides and flame retardant material according to the present invention, methods for preparing these compositions and methods for molding these articles.

As described herein, in many embodiments of the present invention, the flame retardant polymer composition comprises (i) a polymer, (ii) a flame retardant agent of the present invention, and (iii) one or more additional flame retardants, and/or one or more flame retardant synergists or adjuvants. funds. Thus, although flame retardant (ii) alone exhibits excellent activity in polymer systems, it can be used in combination with (iii) one or more compounds selected from other flame retardants, synergists and adjuvants. Examples of compounds (iii) include halogenated flame retardants, alkyl or arylphosphine oxides, alkyl or aryl polyphosphine oxides, alkyl or aryl phosphates, alkyl or aryl phosphonates, alkyl or aryl phosphinates, alkyl or aryl phosphinic acid salts, carbon black, graphite, carbon nanotubes, siloxanes , polysiloxanes, polyphenylene ether, melamine, melamine derivatives, melamine condensation products, melamine salts, metal hydroxides, metal oxides, metal oxide hydrates, metal borates, metal carbonates, metal sulfates, metal phosphates, metal phosphonates, metal phosphites, metal hypophosphites, metal silicates and mixed metal salts. For example, one or more compounds (iii) may be selected from aluminum tris(dialkylphosphinate), aluminum hydrophosphite, benzylphosphine oxides, polybenzylphosphine oxides, melam, melem, melon, melamine phosphates, melamine metal phosphates, melamine cyanurate, melamine borate, talc, clays, calcium silicate , aluminosilicate, hollow tube aluminosilicate, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, boron phosphate, calcium molybdate, expanded vermiculite, zinc stannate, zinc hydroxystannate, zinc sulfide, zinc borate, zinc molybdate, zinc phosphate, magnesium oxide , magnesium hydroxide, aluminum oxide, aluminum oxide hydroxide, aluminum trihydrate, silicon dioxide, tin oxide, antimony (III and V) oxide, antimony (III and V) oxide hydrate, titanium oxide, zinc oxide, zinc oxide hydrate, zirconium oxide and zirconium hydroxide. For example, one or more compounds (iii) may be selected from aluminum tris(dimethylphosphinate), aluminum tris(diethylphosphinate), aluminum tris(dipropylphosphinate), aluminum tris(dibutylphosphinate), methylene diphenylphosphine oxide substituted polyaryl ether, xylene bis(diphenylphosphine oxide), 1. 2-bis(9,10-dihydro-9-hydroxy-10-phosphaphenanthrene-10-oxide)ethane, 4,4'-bis(diphenylphosphinylmethyl)-1,1'-biphenyl, melam, melem, melon and zinc dimelamine pyrophosphate.

In some embodiments, the flame retardant synergist comprises a material selected from melam, melem, melon, melamine cyanurate, melamine polyphosphate, and melamine poly(metal phosphate) (eg, melamine poly(zinc phosphate) (Safire 400)). In some embodiments, the synergist contains a triazine-based compound, such as the reaction product of trichlorotriazine, piperazine and morpholine, such as poly[2,4-(piperazin-1,4-yl)-6-(morpholin-4)-yl)-1 ,3,5-triazine]/piperazine (MCA® PPM Triazine HF). In some embodiments, the synergist includes a metal hypophosphite, such as aluminum hypophosphite (eg, Italmatch Phoslite® IP-A). In some embodiments, the synergist contains an organic phosphinate, such as an aluminum dialkyl phosphinate, such as diethyl aluminum phosphinate (Exolit OP).

In some embodiments, the flame retardant polymer composition contains one or more compounds selected from hydrotalcite clays, metal borates, metal oxides, and metal hydroxides, such as metal borates, metal oxides, or metal hydroxides, where the metal is zinc or calcium.

The concentration of the flame retardant of the invention in this polymer composition, of course, depends on the precise chemistry of the flame retardant, the polymer, and other components contained in the final polymer composition. For example, when used as the sole flame retardant component of a polymer composition, the flame retardant agent of the invention may be present in a concentration of from 1 to 50%, for example from 1 to 30% by weight, of the total weight of the final composition. Typically, when used as the sole flame retardant agent, at least 2% of the material of the invention will be present, for example, 3% or more, 5% or more, 10% or more, 15% or more, 20% or more, or 25% or more . In many embodiments, the flame retardant of the invention is present in an amount of up to 45%, while in other embodiments, the amount of the flame retardant of the invention is 40% of the polymer composition or less, such as 35% or less. When used in combination with other flame retardants or flame retardant synergists, less material of the invention may be required.

Any known formulation techniques can be used to prepare the flame retardant polymer composition of the present invention, for example, the flame retardant agent can be incorporated into the molten polymer by mixing, extrusion, fiber or film spinning, etc. In some cases, the flame retardant is incorporated into the polymer during formation or curing of the polymer, for example, the flame retardant may be added to the polyurethane prepolymer prior to polymer cross-linking, or it may be added to the polyamine or alkyl polycarboxyl compound prior to formation of the polyamide or to the epoxy mixture prior to curing.

The flame retardant polymer composition of the invention will often contain one or more conventional stabilizers or other additives commonly found in the art, such as phenolic antioxidants, hindered amine light stabilizers (HALS), ultraviolet light absorbers, phosphites, phosphonites, alkali metal salts with fatty acids, hydrotalcites, metal oxides, borates, epoxidized soybean oils, hydroxylamines, tertiary amine oxides, lactones, thermal reaction products of tertiary amine oxides, thiosynergists, basic co-stabilizers, e.g. melamine, melem, etc., polyvinylpyrrolidone, dicyandiamide, triallyl cyanurate, urea derivatives, hydrazine derivatives, amines, polyamides, polyurethanes, hydrotalcites, alkali metal salts and alkaline earth metal salts with higher fatty acids, e.g. calcium stearate, calcium stearoyl lactate, calcium lactate, zinc stearate, zinc octoate, magnesium stearate, sodium ricinoleate and potassium palmitate, antimony pyrocatecholate or zinc pyrocatecholate, nucleating agents, brightening agents, etc.

Other additives may also be present, such as plasticizers, lubricants, emulsifiers, pigments, dyes, optical brighteners, other flame retardants, antistatic agents, blowing agents, anti-drip agents such as PTFE, and the like.

If desired, the polymer may include fillers and reinforcing agents, such as calcium carbonate, silicates, fiberglass, talc, kaolin, mica, barium sulfate, metal oxides and hydroxides, carbon black and graphite. Such fillers and enhancing agents may often be present in relatively high concentrations, including compositions in which the filler or enhancing agent is present at concentrations greater than 50% by weight. in terms of the mass of the final composition. More typically, fillers and enhancing agents are present in an amount of from about 5 to about 50% by weight, for example, from about 10 to about 40% by weight. or from about 15 to about 30% of the mass. based on the weight of the entire polymer composition.

In some embodiments, the polymer composition of the present invention may be formulated with one or more materials selected from carbon black, graphite, carbon nanotubes, siloxanes, polysiloxanes, talc, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, calcium silicate , magnesium silicate, aluminosilicate hollow tubes (Dragonite), halloysite, boron phosphate, calcium molybdate, expanded vermiculite, zinc stannate, zinc hydroxystannate, zinc sulfide, zinc borate, zinc molybdate (or complexes thereof, e.g. Kemgard 911B), calcium molybdate complex /magnesium hydroxide (for example, Kemgard MZM), zinc molybdate/magnesium silicate complex (Kemgard 911C), calcium molybdate/zinc complex (for example, Kemgard 911A), zinc phosphate (or complexes thereof, for example, Kemgard 981) and the like, hydroxides , oxides and hydrates of (semi)metal oxides from groups 2, 4, 12, 13, 14, 15, e.g. oxides or hydroxides of magnesium, alumina, alumina hydroxide (boehmite), aluminum trihydrate, silicon dioxide, silicates, tin oxide , antimony (III and V) oxide and oxide hydrate, titanium oxide and zinc oxide oxide or hydrate, zirconium oxide and/or zirconium hydroxide and the like, melamine and urea resins such as melamine cyanurate, melamine borate, melamine polyphosphate, melamine pyrophosphate, polyphenylene ether (PPE) and the like, and clays including, for example, hydrotalcite, boehmite, kaolin, mica, montmorillonite, wollastonite, nanoclays or organically modified nanoclays, and the like.

In some embodiments, the flame retardant polymer composition of the present invention is formulated with any one or more materials selected from zinc borate, zinc stannate, polysiloxanes, kaolin, silica, magnesium hydroxide, zinc molybdate complex (e.g., Kemgard 911B), molybdate complex zinc/magnesium hydroxide (e.g. Kemgard MZM), zinc molybdate/magnesium silicate complex (Kemgard 911C), calcium molybdate/zinc complex (e.g. Kemgard 911A), zinc phosphate complex (e.g. Kemgard 981) and melamine poly(metal phosphate) ( e.g. melamine poly(zinc phosphate) (Safire 400)).

In some embodiments, in addition to the polymer (such as described herein) and the flame retardant agent of the present invention, the flame retardant polymer composition contains melam and any one or more materials selected from zinc borate, zinc stannate, zinc molybdate complex, molybdate complex zinc/magnesium hydroxide, zinc molybdate/magnesium silicate complex, calcium/zinc molybdate complex, zinc phosphate and zinc oxide complex, if desired with additional additives such as those described herein.

In some embodiments, in addition to the polymer (such as described herein) and the flame retardant agent of the present invention, the flame retardant polymer composition contains melon and any one or more materials selected from zinc borate, zinc stannate, zinc molybdate complex, molybdate complex zinc/magnesium hydroxide, zinc molybdate/magnesium silicate complex, calcium/zinc molybdate complex, zinc phosphate and zinc oxide complex, if desired with additional additives such as those described herein.

Further non-limiting disclosure is provided in the following examples.

EXAMPLES

Example 1

114.6 g of methylphosphonic acid was loaded into a 250 ml three-neck flask, which was then heated. At 105°C, methylphosphonic acid melts, and intensive stirring begins in an N ₂ atmosphere. Methylphosphonic acid was heated to 240°C and 7.78 g of alumina was added as quickly as possible without causing a strong exothermic effect. The slurry was cooled until it was just above the melting point of the excess methylphosphonic acid, ~110°C, and then 250 ml of H ₂ O was added, being careful that the rate of addition did not cause excessive steam production. The resulting mixture was stirred to break up any large lumps that may have formed, the product was isolated by filtration, washed with an additional 750 ml of H ₂ O and dried to obtain 45.08 g of product as fine colorless crystals with a yield of 87%. The above empirical product formula represents the repeating monomeric structural units (ie, coordination units) of the coordination polymer forming the pure crystalline product. Thermogravimetric analysis (TGA) of this product is shown in FIG. 1

Example 2

A 250 ml three-neck flask was charged with 149.8 g of ethylphosphonic acid, which was heated until melted, 62°C. Vigorous stirring was started under N ₂ atmosphere, the ethylphosphonic acid was heated to 240° C. and 6.9 g of alumina was added as quickly as possible without causing a strong exothermic effect. The slurry was cooled to ~80°C and then added to 250 ml H ₂ O, ensuring that the rate of addition did not cause excessive steam production. The resulting mixture was stirred to break up any large lumps that may have formed, the product was isolated by filtration, washed with an additional 750 ml of H ₂ O and dried to obtain 49.07 g of product as fine colorless crystals with a yield of 84%. The above empirical product formula represents the repeating monomeric structural units (ie, coordination units) of the coordination polymer forming the pure crystalline product.

Example 3

83 g of methylphosphonic acid was loaded into the resin reservoir and heated to 120°C. An intermediate material prepared from 50 g of methylphosphonic acid and 35.4 g of aluminum tris(isopropoxide) in the presence of water was added to this resin tank in the form of a syrup. The resulting solution, having a molar ratio of methylphosphonic acid: intermediate compound of methylphosphonic acid and aluminum of 5:1, was heated to 240°C with mechanical stirring. Stirring was continued at 240°C for approximately 30 minutes after a solid formed. 500 ml H ₂ O was added and the mixture was stirred for 16 hours until a homogeneous slurry was obtained. As above, the product was isolated by filtration, washed with an additional 750 ml of H ₂ O and dried, obtaining 64.3 g of product in the form of fine colorless crystals with a yield of 93%. The above empirical product formula represents the repeating monomeric structural units (ie, coordination units) of the coordination polymer forming the pure crystalline product.

Example 4

1305 g of methylphosphonic acid was loaded into a 1-liter three-neck flask, which was then heated. At 105°C, methylphosphonic acid melted and vigorous stirring was started under vacuum. This methylphosphonic acid was heated to 180° C. and 61 g of alumina was added as quickly as possible without causing severe exotherm or excessive foaming. The slurry was cooled until it was just above the melting point of excess methylphosphonic acid, ~110°C, and then added to 1 L of H ₂ O, being careful that the rate of addition did not cause excessive steam production. The resulting mixture was stirred to break up any large lumps that may have formed and the product was isolated by filtration, washed with an additional 1.5 L of H ₂ O and dried to give 408 g of product as fine colorless crystals in 84% yield. The above empirical product formula represents the repeating monomeric structural units (ie, coordination units) of the coordination polymer forming the pure crystalline product.

The products from each of Examples 1-4 had a P to Al ratio of 4:1 (ICP elemental analysis).

Example 5

1412.6 g of methylphosphonic acid was charged into a 1 L reaction vessel, which was then heated to 165 °C under a nitrogen atmosphere (4 L/min) with a stirring speed of 250 rpm. 78.2 g of iron oxide was added in portions without causing a strong exothermic effect. The reaction mixture was heated at 165°C for approximately 24 hours. The product reaction mixture containing the off-white slurry was then cooled to approximately 130°C and poured into 1.5 L of water in a beaker cooled in an ice water bath. The product was isolated by filtration, washed with an additional 3×500 ml of water and dried to obtain fine off-white crystals in 83% yield. The product had a phosphorus to iron ratio of 4:1 (ICP elemental analysis) according to the following empirical formula:

The above empirical product formula represents the repeating monomeric structural units (ie, coordination units) of the coordination polymer forming the pure crystalline product.

Example 6

Resin compositions have been formulated and evaluated for flame retardant performance in accordance with UL-94 testing. UL-94 V-0 ratings at 0.8 mm thickness were measured for glass fiber-filled polyamide 6,6, polyamide 6, polybutylene terephthalate (PBT) and high temperature polyamide polymer compositions containing a flame retardant prepared in accordance with Examples 1 above. 3 and 4 (shown below):

Additional polymer compositions containing the flame retardant prepared in accordance with Examples 1, 3 and 4 above, in combination with various synergists containing glass fiber filler PA 66, PBT and polyphthalamide, were prepared and evaluated in UL-94 tests at thickness 0.8 mm. The results are presented in Table 2 (PA 66), Table 3 (PBT) and Table 4 (polyphthalamide). Samples 15, 20 and 22, which did not contain the flame retardant of the invention, failed the UL-94 test.

Example 7

Polymer compositions containing the flame retardant prepared in accordance with Example 5 above in PA 66 were prepared and evaluated for fire resistance under UL-94 testing at a thickness of 0.8 mm. The results are presented in Table 5. Sample 24, which did not contain the flame retardant of the invention, failed the UL-94 test.

Although specific embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art from consideration of the description and practical portion of the present disclosure that various modifications and changes may be made without departing from the scope of the invention as claimed. Accordingly, it is intended that the description and examples are to be considered as illustrative only, with the true scope of the present invention being indicated by the following claims and their equivalents.

Claims (40)

1. A method for producing a phosphorus-containing fire-resistant agent, including interaction at a reaction temperature of a mixture containing a metal compound and a stoichiometric excess relative to the metal compound of an alkyl-substituted phosphonic acid, wherein - the metal compound is an oxide or alkoxide of Al or Fe; - the molar ratio of alkyl-substituted phosphonic acid and metal compound in the mixture is above 4:1; - the reaction temperature is 105°C or higher; And - alkyl-substituted phosphonic acid is in a molten state at the reaction temperature. 2. A method for producing a phosphorus-containing fire-resistant agent, including interaction at a reaction temperature of a mixture containing a metal compound and a stoichiometric excess relative to the metal compound of alkyl-substituted pyrophosphonic acid, wherein - the metal compound is an oxide or alkoxide of Al or Fe; - the molar ratio of alkyl-substituted pyrophosphonic acid and metal compound in the mixture is above 2:1; And - alkyl-substituted pyrophosphonic acid is in a molten state at the reaction temperature. 3. The method according to claim 1, wherein the reaction temperature is 150°C or higher. 4. Method according to claim 1, wherein the reaction temperature varies from 140 to 260°C. 5. The method according to claim 2, wherein the reaction temperature is 40°C or higher. 6. Method according to claim 2, wherein the reaction temperature varies from 60 to 260°C. 7. Method according to claim 1, wherein the molar ratio is 8:1 or higher. 8. Method according to claim 7, wherein the molar ratio varies from 10:1 to 50:1. 9. Method according to claim 2, wherein the molar ratio is 4:1 or higher. 10. Method according to claim 9, wherein the molar ratio varies from 5:1 to 25:1. 11. Method according to claim 1, wherein the alkyl-substituted phosphonic acid is represented by formula (I) where R represents a C1-12 alkyl or a _C7-18 alkylaryl which is unsubstituted or substituted with halogen, hydroxyl, amino, C1-4 alkylamine, di- _C1-4 alkylamine, alkoxyl -4 carbon atoms, carboxyl or alkoxycarbonyl with 2-5 carbon atoms in the alkoxyl. 12. Method according to claim 2, wherein the alkyl-substituted pyrophosphonic acid is represented by formula (Ia) where R represents a C1-12 alkyl or a _C7-18 alkylaryl which is unsubstituted or substituted with halogen, hydroxyl, amino, C1-4 alkylamine, di- _C1-4 alkylamine, alkoxyl -4 carbon atoms, carboxyl or alkoxycarbonyl with 2-5 carbon atoms in the alkoxyl. 13. The method according to claim 11 or 12, wherein R represents unsubstituted alkyl with 1-12 carbon atoms or C _7-10 -alkylaryl. 14. The method according to claim 13, wherein R represents unsubstituted alkyl with 1-6 carbon atoms. 15. The method according to claim 11 or 12, wherein R represents methyl, ethyl, propyl, isopropyl, butyl or tert-butyl. 16. Phosphorus-containing fire-resistant agent obtained in accordance with the method according to any one of paragraphs. 1-15, wherein this phosphorus-containing fire-retardant agent contains a compound of empirical formula (III), where R represents an alkyl or alkylaryl group, M represents a metal, and y is 2 or 3, so that M ^(+)y represents a metal cation, where (+)y represents the charge formally assigned to the cation, a, b and c represent the ratio of the components to which they correspond relative to each other in the compound and satisfy the charge balance equation 2(a)+c=b(y), and c is not equal to zero. 17. Phosphorus-containing fire-resistant agent according to claim 16, wherein y is 3, a is 1, b is 1 and c is 1. 18. Fire-resistant material containing a compound of empirical formula (IIIa) where R represents an alkyl or alkylaryl group. 19. The fire-resistant material according to claim 18, wherein R represents alkyl. 20. Fire-resistant material according to claim 18, wherein R represents alkyl with 1-6 carbon atoms. 21. The fire-resistant material according to claim 18, wherein R represents methyl or ethyl. 22. The fire-resistant material according to claim 18, wherein R represents methyl. 23. Fire-resistant material according to any one of paragraphs. 18-22, wherein the compound of empirical formula (IIIa) constitutes at least 75% by weight of the flame retardant material. 24. The fire-resistant material according to claim 23, wherein the compound of empirical formula (IIIa) constitutes at least 90% by weight of the fire-resistant material.

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