Dialkylphosphinate composition, method of preparation thereof, and use

Abstract

Dialkyl phosphate composition, its preparation method and use. The dialkyl phosphate composition includes diethyl phosphate having a chemical formula represented by formula (I) and long-chain dialkyl phosphate having a chemical formula represented by formula (II). The dialkyl phosphate composition is easy to prepare, has a small addition amount, high flame retardancy efficiency for polymer materials, and excellent thermal stability. It overcomes the disadvantage of low flame retardancy efficiency of diethyl phosphate for polymer materials, and also overcomes the disadvantages of low thermal stability and a large amount of smoke during combustion of long-chain dialkyl phosphate, and can be widely used for flame retardancy of polymer materials that require high-temperature processing.

Description

[Technical Field]

[0001] The present invention relates to a method for preparing and using dialkylphosphinate compositions, and belongs to the field of preparation of flame-retardant polymer materials. [Background technology]

[0002] Dialkylphosphinates, particularly aluminum diethylphosphinate, are widely used as halogen-free flame retardants for polymer materials. However, among conventional dialkylphosphinates, those other than the highly volatile diisobutylphosphinate and dipropylphosphinate have limited flame retardancy in polymer materials, and synergistic agents are necessary for the polymer material to reach UL-94 V0 grade.

[0003] U.S. Patents such as US6207736, US6255371, and US6547992 disclose that diethylphosphinate and inorganic compounds such as ammonium polyphosphate, melamine polyphosphate, and / or zinc stannate synergistically result in flame-retardant glass fiber-reinforced polyamides and polyesters. However, the amount of flame retardant is high, ammonium polyphosphate does not have high thermal stability, and melamine polyphosphate is prone to migration in polymer materials.

[0004] U.S. Patent US7420007 discloses aluminum diethylphosphinate containing 6% or less telomeric dialkylphosphonate. Here, the short-chain polymerized phosphinate is C4-C 10 These are dialkylphosphinates containing long-chain alkyl groups. Chinese patent CN104072537B discloses a method for removing long-chain dialkylphosphinates during the preparation process of diethylphosphinate. Both patents emphasize avoiding the generation and use of long-chain dialkylphosphinates with high content.

[0005] Dialkylphosphinate hybrid salts, prepared by reacting two or more alkenes in the same reaction system as disclosed in another application of the present applicant, exhibit high flame retardancy and high thermal stability, but are not convenient in terms of preparation and precise control of the content of each component, and there is room for improvement.

[0006] Surprisingly, dialkylphosphinate compositions, which consist of long-chain dialkylphosphinates and diethylphosphinates in relatively high concentrations, are easy to prepare, allow for easy control of the content of each component, exhibit high reproducibility, have extremely high flame retardancy efficiency, do not require the use of synergistic agents, and can achieve flame retardancy of polymer materials with the composition alone. It is unexpected that compositions consisting of two or more dialkylphosphinates, which have low flame retardancy efficiency and cannot achieve a good flame retardancy grade for polymer materials, can achieve a high flame retardancy grade for polymer materials. [Overview of the project]

[0007] To solve the above technical problems, the present invention provides a method for preparing and using a dialkylphosphinate composition. The dialkylphosphinate composition comprises component A and component B. This composition is easy to prepare, the component content is easy to control, the amount of flame retardant added is small, the flame retardancy for polymer materials is high, and it is economical.

[0008] According to a first aspect of the present invention, a dialkylphosphinate composition is provided. The dialkylphosphinate composition comprises component A and component B. Component A is at least one compound selected from compounds having the chemical formula represented by formula (I). Component B is at least one compound selected from compounds having the chemical formula represented by formula (II). JPEG0007869883000001.jpg41170 Here, M and N are central atoms, and R1 and R2 are independently C4-C 12 R1 and R2 are selected from alkyl groups, and they may be the same or different, and R1 and R2 may not be isobutyl groups at the same time.

[0009] M and N are each independently selected from metallic elements, and the metallic element is at least one selected from the IIA, IIIA, IVA, VA group metallic elements, transition metal elements, and lanthanide metallic elements.

[0010] Selectively, R1 and R2 are each independently selected from C4-C6 alkyl groups.

[0011] m and n are the valencies of metals M and N, respectively, and m and n are independently selected from 2, 3, or 4.

[0012] Selectively, the dialkylphosphinate composition is composed of component A and component B.

[0013] Selectively, the molar ratio of component A to component B is 1-4.5:4.5-1.

[0014] In this invention, R1 and R2 are each independently C4-C 12 Selected from alkyl groups, which may be the same or different, but which may not all be isobutyl groups at the same time. C4-C 12 The alkyl group may be linear or branched alkyl, and may be n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, sec-pentyl group, tert-pentyl group, n-hexyl group, isohexyl group, sec-hexyl group, tert-hexyl group, n-heptyl group, isoheptyl group, sec-heptyl group, tert-heptyl group, n-octyl group This includes, but is not limited to, tyl groups, isooctyl groups, sec-octyl groups, tert-octyl groups, n-nonyl groups, sec-nonyl groups, tert-nonyl groups, n-decyl groups, isodecyl groups, sec-decyl groups, tert-decyl groups, n-undecyl groups, isoundecyl groups, sec-undecyl groups, tert-undecyl groups, n-dodecyl groups, isododecyl groups, sec-dodecyl groups, and tert-dodecyl groups.

[0015] Optionally, each of R1 and R2 is independently at least one selected from an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group, an n-heptyl group, an n-octyl group, an isooctyl group, a sec-octyl group, and a tert-octyl group, provided that they are not both isobutyl groups at the same time.

[0016] Optionally, each of R1 and R2 is independently at least one selected from an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-hexyl group, an isohexyl group, a sec-hexyl group, and a tert-hexyl group, provided that they are not both isobutyl groups at the same time.

[0017] Optionally, each of R1 and R2 is independently at least one selected from an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group, provided that they are not both isobutyl groups at the same time.

[0018] Optionally, the Group IIA metal element is at least one selected from Be, Mg, Ca, Sr, and Ba.

[0019] The Group IIIA metal element is Al.

[0020] The Group IVA metal element is Sn.

[0021] The Group VA metal element is Sb.

[0022] The transition metal element is at least one selected from Fe, Zn, Cu, Ti, Zr, and Mn.

[0023] The lanthanoid metal element is Ce.

[0024] Optionally, the metal element is at least one selected from Al, Zn, Ca, and Fe.

[0025] Optionally, the metal element is at least one selected from Al, Zn, and Ca.

[0026] Optionally, the metal element is Al, and m = n = 3.

[0027] In the present invention, component A is at least one diethylphosphinate having a chemical formula represented by formula (I). Here, component A may be pure diethylphosphinate, for example, aluminum diethylphosphinate, or a mixture of diethylphosphinates composed of different metal ions, for example, a mixture composed of aluminum diethylphosphinate and zinc diethylphosphinate or iron diethylphosphinate. Optionally, component A is a single diethylphosphinate. Optionally, component A is aluminum diethylphosphinate.

[0028] In the actual preparation process, the diethylphosphinate contains a small amount of oligomers, for example, ethylbutylphosphinate and ethylhexylphosphinate. However, if the molar number of these oligomers is less than 10 mol% with respect to the total molar number of the diethylphosphinate, there is no visible effect on the flame retardant function of the diethylphosphinate. Therefore, in the present invention, the diethylphosphinate containing oligomers of 10 mol% or less is regarded as pure diethylphosphinate. When calculating the molar number of the diethylphosphinate, the molecular weight of the diethylphosphinate is used.

[0029] In the present invention, component B is at least one long-chain dialkylphosphinate having the chemical formula represented by formula (II). Here, component B may be a single long-chain dialkylphosphinate, for example, di-n-butylphosphinate, or a mixture of dialkylphosphinates consisting of different long-chain alkyl groups, for example, a mixture of di-n-butylphosphinate and di-n-hexylphosphinate. Furthermore, it may be a mixture of long-chain dialkylphosphinates consisting of different metal ions, for example, a mixture of aluminum di-n-butylphosphinate and iron di-n-butylphosphinate, or a mixture of dialkylphosphinates having the same chemical formula but different isomer structures, for example, a mixture of aluminum di-n-butylphosphinate and aluminum n-butylsec-butylphosphinate.

[0030] In the composition of the present invention, the molar ratio of component A to component B is 1-4.5:4.5-1. If the ratio is greater than 4.5:1 or less than 1:4.5, the resulting composition will not have high flame retardancy, and if the proportion of diethylphosphinate is too low, the thermal stability of the composition will decrease.

[0031] Selectively, the molar ratio of component A to component B is 1-4.5:4-1.

[0032] Selectively, the molar ratio of component A to component B is 1-4.5:3-1.

[0033] Selectively, the molar ratio of component A to component B is 1-4.5:2-1.

[0034] Selectively, the molar ratio of component A to component B is 1-4.5:1.

[0035] Selectively, the molar ratio of component A to component B is 1-4.3:1.

[0036] Selectively, the molar ratio of component A to component B is 1-4:1.

[0037] In the embodiments of the present invention, when long-chain dialkylphosphinate and diethylphosphinate are used individually, neither can achieve an effective flame retardant grade, such as UL-94 V0 grade, as a polymer material at the same dose. However, compositions composed of them can achieve excellent flame retardancy, such as UL-94 V0, as a polymer material. This is quite surprising.

[0038] The composition described in the present invention can be obtained by physically mixing component A and component B, respectively, i.e., diethylphosphinate and long-chain dialkylphosphinate, according to a specific molar ratio. This physical mixing process may be carried out before processing the flame-retardant polymer material or during the preparation process of the flame-retardant polymer material. For convenience, the composition of component A and component B obtained by this method will be abbreviated as the physical composition.

[0039] A second aspect of the present invention provides a method for preparing the dialkylphosphinate composition. The method involves carrying out reaction I in an aqueous phase with a starting material having a diethylphosphinic acid and / or an alkali metal salt thereof having an anion in the chemical formula of formula (I), a dialkylphosphinic acid and / or an alkali metal salt thereof having an anion in the chemical formula of formula (II), a metal element M source and a metal element N source to obtain the dialkylphosphinate composition, or Component A and component B are mixed to obtain the dialkylphosphinate composition. Component A is selected from component A, and component B is selected from component B.

[0040] In the present invention, the particle size of the composition obtained by coprecipitation (i.e., reaction I carried out in the aqueous phase) is much larger than that of pure aluminum dibutylphosphinate. This overcomes the drawback of large amounts of dust being produced during the physical mixing process.

[0041] In this invention, the amount of water in the coprecipitation reaction is not limited; any amount sufficient to precipitate the product is acceptable.

[0042] Selectively, the preparation method involves carrying out reaction I in an aqueous phase with raw materials comprising diethylphosphinic acid and / or its alkali metal salt having the anion in the chemical formula of formula (I), at least one R1R2 group phosphinic acid and / or its alkali metal salt having the anion in the chemical formula of formula (II), and metal element M and N sources, to obtain a dialkylphosphinate precipitate, which is separated and dried to obtain a dialkylphosphinate composition consisting of the chemical formulas represented by formulas (I) and (II). For convenience, the composition prepared by this method is abbreviated as a coprecipitation composition.

[0043] In the present invention, the molar ratio of diethylphosphinic acid and / or its alkali metal salt having the anion in the chemical formula of formula (I), dialkylphosphinic acid and / or its alkali metal salt having the anion in the chemical formula of formula (II), the metal element M source, and the metal element N source is the same as or close to the molar ratio of the corresponding components in the dialkylphosphinic acid composition.

[0044] Selectively, the conditions for reaction I are a temperature of 0-250°C, a pressure of 0.1 MPa-10 MPa, and a time of 0.01-20 h.

[0045] Selectively, reaction I is carried out under conditions of pH 0-4.

[0046] Selectively, the metal element is Al, i.e., M=N=Al. The pH of reaction I is 0-4, preferably 1-3.5, and more preferably 2.3-3.3.

[0047] Specifically, if the pH of reaction I is too low, no precipitate will form. If the pH is too high, metal ion hydroxides will be generated, introducing impurities.

[0048] Selectively, the metal element M source is at least one selected from salts of the metal element M.

[0049] The aforementioned metal element N source is at least one selected from salts of the metal element N.

[0050] Selectively, the salt of the metal element M is at least one selected from the nitrates, sulfates, hydrochlorides, acetates, and oxides of the metal element M.

[0051] Selectively, the salt of the metal element N is at least one selected from nitrates, sulfates, hydrochlorides, acetates, and oxides of the metal element N.

[0052] Selectively, the molar ratio of diethylphosphinic acid and / or its alkali metal salt, R1R2 group phosphinic acid and / or its alkali metal salt, to the metal element M and N sources is equal to or close to the theoretical equivalent calculated based on equations (I) and (II).

[0053] The dialkylphosphinate precipitate is separated using conventional methods, such as filtration, centrifugation, and removal of the liquid phase leaving the solid phase. Drying is performed using common methods such as baking.

[0054] Selectively, the order in which the reactants are added during reaction I can be arbitrarily adjusted. For example, diethylphosphinic acid and / or its alkali metal salt may be homogeneously mixed with R1R2 group phosphinic acid and / or its alkali metal salt, and then reacted with the metal element M and N source raw materials in the aqueous phase.

[0055] When selectively carrying out reaction I, diethylphosphinic acid and / or its alkali metal salt, and R1R2 group phosphinic acid and / or its alkali metal salt are added to an aqueous phase containing metal element M and N raw materials, respectively, and reacted.

[0056] In the dialkylphosphinate composition obtained by reaction I, the content of components A and B can be determined by conventional means such as the initial input amounts, the molar ratio of dialkylphosphinate ions, and elemental analysis. In simple cases, for example, if component A is aluminum diethylphosphinate and component B is aluminum dibutylphosphinate, the resulting composition is dissolved in alkaline or acidic water. Then, the molar ratio of diethylphosphinate ions to dibutylphosphinate ions is determined by the peak area of ​​the phosphorus NMR spectrum, and this molar ratio of the two becomes the molar ratio of component A to component B. In more complex cases, for example, if different metal ions are used, the molar ratio of component A to component B can be calculated by further methods such as elemental analysis.

[0057] Diethylphosphinic acid and / or its alkali metal salts and R1R2 group phosphinic acid and / or its alkali metal salts can be prepared by known methods. For example, diethylphosphinic acid and / or its alkali metal salts can be obtained by an addition reaction of ethylene and phosphinic acid and / or its alkali metal salt in aqueous solution in the presence of a free radical initiator.

[0058] In the preparation of diethylphosphinic acid and / or its alkali metal salts and R1R2 group phosphinic acid and / or its alkali metal salts, the reaction process may produce at least one of phosphate ions, phosphite ions, alkylphosphonate ions, and alkylphosphinate ions. These acid ions may be incorporated into the composition by forming corresponding metal salt precipitates under certain conditions. Therefore, selectively, dialkylphosphinate compositions comprising compounds having structures represented by formulas (I) and (II) may also include metal salts formed from M or N metal ions with at least one of phosphate ions, phosphite ions, alkylphosphonate ions, and alkylphosphinate ions. The molar content of these phosphorus-containing metal salts in the dialkylphosphinate composition is 10% or less. The molar number is calculated from the number of moles of phosphorus element contained. Selectively, the molar content of these phosphorus-containing metal salts in the dialkylphosphinate composition is 5% or less.

[0059] Preferably, the dialkylphosphinate composition comprising component A and component B is a coprecipitation composition. This coprecipitation composition has the advantage of having a large particle size and producing less dust during use, thus overcoming the disadvantage of having small particle sizes and large dust in physical compositions due to components A and / or B.

[0060] A third aspect of the present invention provides a flame retardant. The flame retardant is at least one selected from the dialkylphosphinate composition and the dialkylphosphinate composition prepared by the method described above.

[0061] According to a fourth aspect of the present invention, a flame-retardant material is provided. The flame-retardant material comprises a flame retardant P and a thermoplastic polymer material. The flame retardant P is at least one selected from the flame retardants.

[0062] Selectively, the flame retardant P has a mass content of 1-35% in the flame retardant material.

[0063] Selectively, the upper limit of the mass content of the flame retardant P in the flame retardant material is independently selected from 35%, 30%, 25%, 20%, 15%, 10%, and 5%, and the lower limit is independently selected from 1%, 30%, 25%, 20%, 15%, 10%, and 5%.

[0064] Selectively, the flame retardant material comprises 1-35 wt% of a flame retardant P and 65-99 wt% of a thermoplastic polymer material.

[0065] In this invention, the term "thermoplastic polymer material" refers to a plastic that has the property of softening when heated and hardening when cooled.

[0066] Specifically, the amount of flame retardant P used depends on the thermoplastic polymer material.

[0067] Selectively, the flame retardant P is present in a mass content of 3-20% in the flame retardant material.

[0068] Selectively, the flame retardant material further contains functional additives.

[0069] The functional additive comprises at least one selected from reinforcing agents, anti-dropping agents, stabilizers, pigments, dyes, carbon generation catalysts, dispersants, nucleating agents, inorganic fillers, and antioxidants.

[0070] Preferably, the functional additive is present in the flame retardant material at a mass content of 5-40%.

[0071] Selectively, the functional additive is selected from an upper limit of 40%, 35%, 30%, 25%, 20%, 15%, and 10% by mass content in the flame retardant material, and from a lower limit of 5%, 35%, 30%, 25%, 20%, 15%, and 10%.

[0072] Selectively, the reinforcing agent is selected from glass fibers.

[0073] The drip-preventing agent is selectively selected from Teflon.

[0074] Selectively, the inorganic filler is at least one selected from mica, calcium carbonate, calcium oxide, and silica.

[0075] Selectively, the flame retardant further contains flame retardant Q.

[0076] The flame retardant Q is at least one selected from nitrogen-based flame retardants and boron-based flame retardants.

[0077] Selectively, the nitrogen-based flame retardant is at least one selected from melamine cyanurate, melamine polyphosphate, and ammonium polyphosphate.

[0078] The boron-based flame retardant is selected from zinc borate.

[0079] Selectively, the flame retardant Q has a mass content of 0.5-20% in the flame retardant material.

[0080] Selectively, the upper limit of the mass content of the flame retardant Q in the flame retardant material is independently selected from 20%, 15%, 10%, 5%, and 1%, and the lower limit is independently selected from 0.5%, 15%, 10%, 5%, and 1%.

[0081] Selectively, the thermoplastic polymer material is at least one selected from polyamide and polyester.

[0082] Selectively, the polyamide is at least one selected from aliphatic polyamides, aromatic polyamides, semi-aromatic polyamides, and copolymers of semi-aromatic polyamides and aliphatic polyamides.

[0083] According to the ordinary knowledge of the art, polyamides, also known as nylon, are a general term for polymers containing an -NH-C(O)-amide group in their structural units, and are synthesized by condensation or ring-opening reactions of one or more dicarboxylic acids and one or more diamines, and / or one or more amino acids, and / or one or more lactams. Based on the composition of their main chain, polyamides are usually classified into aliphatic polyamides, aromatic polyamides, and semi-aromatic polyamides. Semi-aromatic polyamides are those in which at least one monomer structure of the synthetic monomer contains an aromatic group.

[0084] Selectively, the aliphatic polyamide is a copolymer of polyamide 6 and polyamide 66, or a mixture of one or more polyamides arbitrarily selected from polyamide 6 and polyamide 66.

[0085] Selectively, the semi-aromatic polyamide can be prepared using any one or more aromatic dicarboxylic acids and any one or more aliphatic diamines, or using any one or more aromatic diamines and any one or more aliphatic dicarboxylic acids. A polyamide copolymer having the corresponding properties can be prepared by further adding one or more selected from dicarboxylic acids, diamines, lactams, and amino acids to the reaction system. The added dicarboxylic acid is an aromatic dicarboxylic acid and / or an aliphatic dicarboxylic acid. The added diamine is an aromatic diamine and / or an aliphatic diamine. The added lactam may be an aliphatic or aromatic lactam. The added amino acid may be an aromatic or aliphatic amino acid.

[0086] Selectively, the semi-aromatic polyamide is prepared using one or more aromatic dicarboxylic acids selected from terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, and one or more aliphatic diamines selected from butanediamine, hexamethylenediamine, octanediamine, decanediamine, and 2-methylpentanediamine.

[0087] Selectively, the semi-aromatic polyamides are prepared using aliphatic diamines, aromatic dicarboxylic acids, and aliphatic dicarboxylic acids.

[0088] Selectively, the semi-aromatic polyamide is prepared using an aliphatic diamine and an aromatic dicarboxylic acid. Selectively, an aliphatic dicarboxylic acid may be further added. The mole fraction of the aliphatic dicarboxylic acid is 0-45% of the total amount of dicarboxylic acid. That is, the number of moles of aliphatic dicarboxylic acid / (number of moles of aliphatic dicarboxylic acid + number of moles of aromatic dicarboxylic acid) = 0-45%.

[0089] Selectively, the aromatic dicarboxylic acid is one or more selected from terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid. The aliphatic diamine is one or more selected from butanediamine, hexamethylenediamine, octanediamine, decanediamine, and 2-methylpentanediamine. The aliphatic dicarboxylic acid is one or more selected from adipic acid, succinic acid, sebacic acid, and suberic acid.

[0090] Selectively, the polyamides include polyhexamethylene terephthalamide (abbreviated as PA6T), polyhexamethylene isophthalamide (abbreviated as PA6I), terephthalic acid / hexamethylenediamine / caprolactam copolymer (abbreviated as PA6T / 6), terephthalic acid / hexamethylenediamine / adipic acid copolymer (abbreviated as PA6T / 66), terephthalic acid / hexamethylenediamine / adipic acid / isophthalic acid copolymer (abbreviated as PA6T / 6I / 66), polynonameethylene terephthalamide (abbreviated as PA9T), and polydecanediamine. It is one or more selected from terephthalamide (abbreviated as PA10T), polidodecylterephthalamide (abbreviated as PA12T), terephthalic acid / hexamethylenediamine / deuterolactam copolymer (abbreviated as PA6T / 12), poly(m-xylyleneadipamide) (abbreviated as MXD6), terephthalic acid / hexamethylenediamine / 2-methylpentanediamine copolymer (abbreviated as PA6T / 2-MPMDT), and terephthalic acid / 2,2,4-trimethylhexamethylenediamine / 2,4,4-trimethylhexamethylenediamine copolymer.

[0091] Selectively, the aliphatic polyamide is at least one selected from polyamide 6, polyamide 66, and a copolymer of polyamide 6 and polyamide 66.

[0092] The semi-aromatic polyamide is selectively selected from polyphthalamides (PPAs).

[0093] Selectively, the polyester is selected from polybutylene terephthalate (PBT).

[0094] The present invention has the following beneficial effects. (1) The dialkylphosphinate composition provided in the present invention, comprising components A and B, requires a small amount of additive, has high flame retardancy efficiency for polymer materials, and is highly economical. The drawback of diethylphosphinate and long-chain dialkylphosphinate having low flame retardancy efficiency for polymer materials is overcome, and the drawback of low thermal stability when long-chain dialkylphosphinate is used alone is resolved, making it widely applicable for flame retardation of polymer materials requiring high-temperature processing. (2) The dialkylphosphinate composition provided in the present invention, comprising component A and component B, is easy to prepare, allows for precise control of the proportions of the different components, and can guarantee the physical performance and stability of the flame retardant material. [Brief explanation of the drawing]

[0095] [Figure 1] This is the 31P-NMR spectrum of the aluminum dialkylphosphinate composition prepared in Example 2 after alkaline hydrolysis. [Figure 2] This is the XRD spectrum of the aluminum dialkylphosphinate compositions prepared in Examples 1-3. [Modes for carrying out the invention]

[0096] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0097] Unless otherwise specified, all raw materials used in the embodiments of this invention were purchased through commercial channels.

[0098] The raw materials used in the examples are as follows: PA66 (also known as polyamide 66 or nylon 66): Zytel 70G35 HSL NC010 from DuPont, USA, with a glass fiber content of 35% by weight.

[0099] PA6 (also known as polyamide 6 or nylon 6): Zytel 73G30L NC010 from DuPont, USA, with a glass fiber content of 30% by weight.

[0100] Aluminum diethylphosphinate: Exolit OP1230, D from Clariant GmbH, Germany. 50 = 30.80 μm.

[0101] Zinc diethylphosphinate: Clariant GmbH, Germany.

[0102] Antioxidant 1010: Tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] pentaerythritol ester, Shanghai Macklin Biochemical Co.,Ltd.

[0103] Antioxidant 168: Tri[2,4-di-tert-butylphenyl]phosphite, Strem, USA.

[0104] Combined antioxidant: A mixture of antioxidant 1010 (tetra[β-(3,5-di-tert-butyl-4-hydroxyphenylpropionic acid]pentaerythritol ester) and antioxidant 168 (tri[2,4-di-tert-butylphenyl]phosphite) in a 1:1 weight ratio.

[0105] Combustion test standard: GB / T 2408-2008 standard.

[0106] Nuclear Magnetic Resonance (NMR) Test: Instrument model AVANCE III 400MHz, Bruker GmbH, Germany.

[0107] Nuclear magnetic resonance - phosphorus 31 P-NMR) Test method: Preliminary delay D1 = 10 seconds, Bruker GmbH, Germany. The ratio of peak areas is defined as the ratio of the number of moles of each phosphonate ion.

[0108] Instrument model used for X-ray diffraction (XRD) testing: D8 ADVANCE DAVINCI, Bruker GmbH, Germany.

[0109] Particle size D50: Dry test using Sympatec Heloise-oasis HELOS (H3938) laser particle size analyzer in Germany.

[0110] Example 1 Preparation of aluminum dialkylphosphinate composition The molar ratio of aluminum diethylphosphinate having the chemical formula (I) to aluminum dibutylphosphinate having the chemical formula (II) is 1.2:1. Preparation of sodium diethylphosphinate: 100 g of sodium phosphinate monohydrate was dissolved in 500 g of water and placed in a 1 L stainless steel pressure vessel. The vessel was purged twice with nitrogen gas, evacuated, and then ethylene was introduced to 0.8 MPa. After heating the reaction mixture to approximately 90°C, a 4% sodium persulfate aqueous solution was introduced at a constant rate of 10 ml / h, and ethylene was continuously introduced into the reaction vessel. The amount of ethylene introduced was measured using a gas flow meter. After 8 hours, the pressure in the system stopped decreasing, so the reaction was stopped, the system was cooled to release the pressure, purged with N2, and the materials were discharged to obtain a clear reaction solution.

[0111] Preparation of sodium dibutylphosphinate: 100 g of sodium phosphinate monohydrate was dissolved in 500 g of water and placed in a 1 L stainless steel pressure vessel. The vessel was purged twice with nitrogen gas, and after vacuuming, butene was introduced until the pressure stopped rising. After heating the reaction mixture to approximately 90°C, a 4% sodium persulfate aqueous solution was added at a constant rate of 10 ml / h, continuing to introduce butene into the reaction vessel, and the amount of butene introduced was measured using a gas flow meter. After 25.5 hours, the pressure of the system stopped decreasing, so the reaction was stopped, the system was cooled to release the pressure, purged with N2, and the materials were discharged to obtain a clear reaction solution.

[0112] Preparation of dialkylphosphinate aluminum composition: 135.37 g (containing 0.18 mol of phosphorus) of the diethylphosphinate sodium solution and 164.52 g (containing 0.18 mol of phosphorus) of the dibutylphosphinate sodium solution were taken and mixed uniformly. Then, these were slowly mixed at atmospheric pressure with a 10% mass concentration aqueous solution containing 39.99 g of aluminum sulfate 18 hydrate. The reaction temperature was controlled to 70°C, and the pH value was adjusted to 3.0 or less to obtain a large amount of precipitate. After adding the raw materials and mixing, the mixture was kept warm for 0.5 hours. The mixture was thermally filtered, the filtered cake was washed with clean water, and then dried at 120°C to obtain 50.06 g of a white solid dialkylphosphinate aluminum composition.

[0113] The aluminum dialkylphosphinate composition obtained in this test was dissolved in an aqueous solution of sodium hydroxide, and phosphorus nuclear magnetic resonance was performed. The result showed that the content of diethylphosphinate ions was 54.55%, and the total content of dibutylphosphinate ions was 45.45%. In other words, in the aluminum dialkylphosphinate composition, the molar ratio of aluminum diethylphosphinate having the chemical formula (I) to aluminum dibutylphosphinate having the chemical formula (II) was 1.2:1.

[0114] The prepared aluminum dialkylphosphinate composition was subjected to XRD analysis. The interlayer distances corresponding to the two characteristic peaks with the highest relative intensity obtained from the XRD analysis were 11.835 angstroms (100%) and 9.680 angstroms (45.1%), respectively.

[0115] The particle size of the prepared aluminum dialkylphosphinate composition was measured, and the result was D 50 The value was 17.78 μm.

[0116] Note: Diethylphosphinate ions include 98% molar diethylphosphinate ions and 2% molar short-chain polymerized diethylphosphinate ions. Dibutylphosphinate ions include n-butylsec-butylphosphinate ions (R1≠R2, where n-butyl and sec-butyl groups are respectively), di-n-butylphosphinate ions (R1=R2=n-butyl group), di-sec-butylphosphinate ions (R1=R2=sec-butyl group), and short-chain polymerized dibutylphosphinate ions. The same applies to the following.

[0117] Example 2 Preparation of aluminum dialkylphosphinate composition The molar ratio of aluminum diethylphosphinate having the chemical formula (I) to aluminum dibutylphosphinate having the chemical formula (II) is 2.4:1. Preparation of dialkylphosphinate aluminum composition: 180.49 g of sodium diethylphosphinate solution (containing 0.24 mol of phosphorus) and 109.68 g of sodium dibutylphosphinate solution (containing 0.12 mol of phosphorus), prepared by the method of Example 1, were uniformly mixed. Then, a 10% by mass aqueous solution containing 39.99 g of aluminum sulfate 18-hydrate was slowly mixed at atmospheric pressure. The reaction temperature was controlled to 70°C, and the pH value was adjusted to 3.0 or less to obtain a large amount of precipitate. After adding the raw materials and mixing, the mixture was kept warm for 0.5 hours. The mixture was thermally filtered, the filtered cake was washed with clean water, and then dried at 120°C to obtain 48.56 g of a white solid dialkylphosphinate aluminum composition.

[0118] The aluminum dialkylphosphonate composition obtained in this test was dissolved in an aqueous solution of sodium hydroxide, and phosphorus nuclear magnetic resonance was performed. As a result, the content of diethylphosphonate ion mole was 69.98%, the total content of dibutylphosphonate ion mole was 29.17%, and the content of other phosphorus-containing impurities, for example, the content of ethylphosphonate ion mole was 0.10%, the content of ethylphosphonate ion mole was 0.13%, the content of butylphosphonate ion mole was 0.43%, and the content of butylphosphonate ion mole was 0.19%. That is, in the aluminum dialkylphosphonate composition, the molar ratio of aluminum diethylphosphonate having the chemical formula represented by formula (I) to aluminum dibutylphosphonate having the chemical formula represented by formula (II) was 2.4:1. The phosphorus nuclear magnetic resonance spectrum ( 31 P-NMR) is shown in Figure 1.

[0119] The prepared aluminum dialkylphosphonate composition was subjected to XRD measurement. The interlayer distances corresponding to the two characteristic peaks with the highest relative intensities obtained by XRD measurement were 11.867 angstroms (78.7%) and 9.681 angstroms (100%), respectively.

[0120] As a result of measuring the particle size of the prepared aluminum dialkylphosphonate composition, D 50 = 23.27 μm.

[0121] Example 3 Preparation of Aluminum Dialkylphosphonate Composition The molar ratio of aluminum diethylphosphonate having the chemical formula represented by formula (I) to aluminum dibutylphosphonate having the chemical formula represented by formula (II) is 3.6:1. Preparation of dialkylphosphinate aluminum composition: 203.05 g of sodium diethylphosphinate solution (containing 0.27 mol of phosphorus) and 82.26 g of sodium dibutylphosphinate solution (containing 0.09 mol of phosphorus), prepared by the method of Example 1, were uniformly mixed. Then, a 10% aqueous solution containing 39.99 g of aluminum sulfate 18-hydrate was slowly mixed at atmospheric pressure. The reaction temperature was controlled to 70°C, and the pH value was adjusted to 3.0 or less to obtain a large amount of precipitate. After adding the raw materials and mixing, the mixture was kept warm for 0.5 hours. The mixture was thermally filtered, the filtered cake was washed with clean water, and then dried at 120°C to obtain 47.72 g of a white solid dialkylphosphinate aluminum composition.

[0122] The aluminum dialkylphosphinate composition obtained in this test was dissolved in an aqueous solution of sodium hydroxide, and phosphorus nuclear magnetic resonance was performed. The result showed that the content of diethylphosphinate ions was 78.36%, and the total content of dibutylphosphinate ions was 21.64%. In other words, in the aluminum dialkylphosphinate composition, the molar ratio of aluminum diethylphosphinate having the chemical formula (I) to aluminum dibutylphosphinate having the chemical formula (II) was 3.6:1.

[0123] The prepared aluminum dialkylphosphinate composition was subjected to XRD analysis. The interlayer distances corresponding to the two characteristic peaks with the highest relative intensity obtained from the XRD analysis were 11.701 angstroms (27.2%) and 9.659 angstroms (100%), respectively.

[0124] The particle size of the prepared aluminum dialkylphosphinate composition was measured, and the result was D 50 The value was 49.20 μm.

[0125] Figure 2 shows the XRD spectra of the aluminum dialkylphosphinate compositions prepared in Examples 1-3. As can be seen from Figure 2, in the region of strongest absorption peaks, there are two independent peaks with essentially constant peak values ​​(d values), belonging to aluminum diethylphosphinate and aluminum dibutylphosphinate, respectively, indicating that the compositions obtained in the present invention are a physical mixture of diethylphosphinate and long-chain dialkylphosphinate.

[0126] Comparative Example 1: Preparation of aluminum dibutylphosphinate 100g of sodium phosphinate monohydrate was dissolved in 500g of water and placed in a 1L stainless steel pressure vessel. The vessel was purged twice with nitrogen gas, and after vacuuming, butene was introduced until the pressure stopped rising. After heating the reaction mixture to approximately 90°C, a 4% sodium persulfate aqueous solution was added at a constant rate of 10ml / h, continuing to introduce butene into the reaction vessel, and the amount of butene introduced was measured with a gas flow meter. After 25.5 hours, the pressure of the system stopped decreasing, so the reaction was stopped, the system was cooled to release the pressure, N2 purged, and the materials were discharged to obtain a clear reaction solution. 394g of the above solution (containing 0.3996 moles of phosphorus) was slowly mixed with a 10% aqueous solution containing 44.38g of aluminum sulfate 18-hydrate. The reaction temperature was controlled to 70°C, the pH was adjusted to 3.0 or less, and a large amount of precipitate was obtained. After adding the raw materials and mixing, the mixture was kept warm for 0.5 hours. The solution was thermally filtered, the filtered cake was washed with clean water, and then dried at 120°C to obtain 67.28 g of aluminum dibutylphosphinate, which is a white solid.

[0127] The particle size of the prepared aluminum dibutylphosphinate was measured, and the result was D 50 The value was 2.27 μm.

[0128] Comparative Example 2: Preparation of aluminum dihexylphosphinate Referring to Comparative Example 1, aluminum dihexylphosphinate was prepared using 1-hexene instead of 1-butene. The product was sticky, therefore D 50 It was not possible to measure it accurately.

[0129] Comparative Example 3: Preparation of iron dihexylphosphinate Referring to Comparative Example 1, iron dihexylphosphinate was prepared using 1-hexene instead of 1-butene and iron(III) chloride hexahydrate instead of aluminum sulfate 18-hydrate. The product was sticky, therefore D 50 It was not possible to measure it accurately.

[0130] Example 4 Polyamide PA66, the aluminum dialkylphosphinate composition prepared in Example 1, and a composite antioxidant were mixed in a mixer at a rotation speed of 50 rpm in a weight ratio of 79.6:20:0.4. The temperature was set to 280°C, and after 5 minutes, the mixture was removed, cooled, and dried. The mixture was then filled into a mold, preheated in a flat vulcanizer at 280°C for 10 minutes, held at 10 MPa for 5 minutes, and then cold-pressed. After cooling, a sample was cut and tested. The flame retardancy grade of the 1.6 mm sample was UL94 V-0.

[0131] Example 5 Polyamide PA6, the aluminum dialkylphosphinate composition prepared in Example 1, and a composite antioxidant were mixed in a mixer at a rotation speed of 50 rpm in a weight ratio of 79.6:20:0.4. The temperature was set to 260°C, and after 5 minutes, the mixture was removed, cooled, and dried. The mixture was then filled into a mold, preheated in a flat vulcanizer at 260°C for 10 minutes, held at 10 MPa for 5 minutes, and then cold-pressed. After cooling, a sample was cut and tested. The flame retardancy grade of the 1.6 mm sample was UL94 V-0.

[0132] Example 6 Polyamide PA66, the aluminum dialkylphosphinate composition prepared in Example 2, and a composite antioxidant were mixed in a mixer at a weight ratio of 79.6:20:0.4 at a rotation speed of 50 rpm. The temperature was set to 280°C, and after 5 minutes, the mixture was removed, cooled, and dried. The mixture was then filled into a mold, preheated in a flat vulcanizer at 280°C for 10 minutes, held at 10 MPa for 5 minutes, and then cold-pressed. After cooling, a sample was cut and tested. The flame retardancy grade of the 1.6 mm sample was UL94 V-0.

[0133] Example 7 Polyamide PA6, the aluminum dialkylphosphinate composition prepared in Example 2, and a composite antioxidant were mixed in a mixer at a rotation speed of 50 rpm in a weight ratio of 79.6:20:0.4. The temperature was set to 260°C, and after 5 minutes, the mixture was removed, cooled, and dried. The mixture was then filled into a mold, preheated in a flat vulcanizer at 260°C for 10 minutes, held at 10 MPa for 5 minutes, and then cold-pressed. After cooling, a sample was cut and tested. The flame retardancy grade of the 1.6 mm sample was UL94 V-0.

[0134] Example 8 Polyamide PA66, the aluminum dialkylphosphinate composition prepared in Example 3, and a composite antioxidant were mixed in a mixer at a weight ratio of 79.6:20:0.4 at a rotation speed of 50 rpm. The temperature was set to 280°C, and after 5 minutes, the mixture was removed, cooled, and dried. The mixture was then filled into a mold, preheated in a flat vulcanizer at 280°C for 10 minutes, held at 10 MPa for 5 minutes, and then cold-pressed. After cooling, a sample was cut and tested. The flame retardancy grade of the 1.6 mm sample was UL94 V-0.

[0135] Example 9 Polyamide PA6, the aluminum dialkylphosphinate composition prepared in Example 3, and a composite antioxidant were mixed in a mixer at a rotation speed of 50 rpm in a weight ratio of 79.6:20:0.4. The temperature was set to 260°C, and after 5 minutes, the mixture was removed, cooled, and dried. It was then filled into a mold, preheated in a flat vulcanizer at 260°C for 10 minutes, held at 10 MPa for 5 minutes, and then cold-pressed. After cooling, a sample was cut and tested. The flame retardancy grade of the 1.6 mm sample was UL94 V-0.

[0136] Example 10 Polyamide PA66, aluminum diethylphosphinate, aluminum dibutylphosphinate prepared in Comparative Example 1, and a composite antioxidant were mixed in a mixer at a rotation speed of 50 rpm in a weight ratio of 79.6:10:10:0.4 (where the molar ratio of aluminum diethylphosphinate to aluminum dibutylphosphinate is 1.43:1). The mixture was set to a temperature of 280°C, removed after 5 minutes, cooled, and dried. The mixture was then filled into a mold, preheated in a flat vulcanizer at 280°C for 10 minutes, held at 10 MPa for 5 minutes, and then cold-pressed. After cooling, samples were cut and tested. The flame retardancy grade of the 1.6 mm sample was UL94 V-0.

[0137] Example 11 Polyamide PA66, aluminum diethylphosphinate, aluminum dibutylphosphinate prepared in Comparative Example 1, and a composite antioxidant were mixed in a mixer at a rotation speed of 50 rpm in a weight ratio of 79.6:15:5:0.4 (where the molar ratio of aluminum diethylphosphinate to aluminum dibutylphosphinate is 4.3:1). The mixture was set to a temperature of 280°C, removed after 5 minutes, cooled, and dried. The mixture was then filled into a mold, preheated in a flat vulcanizer at 280°C for 10 minutes, held at 10 MPa for 5 minutes, and then cold-pressed. After cooling, samples were cut and tested. The flame retardancy grade of the 1.6 mm sample was UL94 V-0.

[0138] Example 12 Polyamide PA66, aluminum diethylphosphinate, aluminum dibutylphosphinate prepared in Comparative Example 1, and a composite antioxidant were mixed in a mixer at a rotation speed of 50 rpm in a weight ratio of 79.6:3:17:0.4 (where the molar ratio of aluminum diethylphosphinate to aluminum dibutylphosphinate is 1:4). The mixture was set to a temperature of 280°C, removed after 5 minutes, cooled, and dried. The mixture was then filled into a mold, preheated in a flat vulcanizer at 280°C for 10 minutes, held at 10 MPa for 5 minutes, and then cold-pressed. After cooling, samples were cut and tested. The flame retardancy grade of the 1.6 mm sample was UL94 V-1.

[0139] Example 13 Polyamide PA66, zinc diethylphosphinate, aluminum dibutylphosphinate prepared in Comparative Example 1, and a composite antioxidant were mixed in a mixer at a rotation speed of 50 rpm in a weight ratio of 79.6:4.3:15.7:0.4 (where the molar ratio of zinc diethylphosphinate to aluminum dibutylphosphinate is 1:2). The mixture was set to a temperature of 280°C, removed after 5 minutes, cooled, and dried. The mixture was then filled into a mold, preheated in a flat vulcanizer at 280°C for 10 minutes, held at 10 MPa for 5 minutes, and then cold-pressed. After cooling, samples were cut and tested. The flame retardancy grade of the 3.2 mm sample was UL94 V-1.

[0140] Example 14 Polyamide PA66, aluminum diethylphosphinate, aluminum dihexylphosphinate prepared in Comparative Example 2, and a composite antioxidant were mixed in a mixer at a rotation speed of 50 rpm in a weight ratio of 79.6:13.65:6.35:0.4 (where the molar ratio of aluminum diethylphosphinate to aluminum dihexylphosphinate is 4:1). The mixture was then set to a temperature of 280°C, removed after 5 minutes, cooled, and dried. The mixture was then filled into a mold, preheated in a flat vulcanizer at 280°C for 10 minutes, held at 10 MPa for 5 minutes, and then cold-pressed. After cooling, samples were cut and tested. The flame retardancy grade of the 1.6 mm sample was UL94 V-0.

[0141] Example 15 Polyamide PA6, aluminum diethylphosphinate, iron dihexylphosphinate prepared in Comparative Example 3, and a composite antioxidant were mixed in a mixer at a rotation speed of 50 rpm in a weight ratio of 79.6:13.5:6.5:0.4 (where the molar ratio of aluminum diethylphosphinate to iron dihexylphosphinate is 4:1). The mixture was set to a temperature of 260°C, removed after 5 minutes, cooled, and dried. The mixture was then filled into a mold, preheated in a flat vulcanizer at 260°C for 10 minutes, held at 10 MPa for 5 minutes, and then cold-pressed. After cooling, samples were cut and tested. The flame retardancy grade of the 1.6 mm sample was UL94 V-0.

[0142] Comparative Example 4 Polyamide PA66, aluminum diethylphosphinate, and a composite antioxidant were mixed in a weight ratio of 79.6:20:0.4 in a mixer at a rotation speed of 50 rpm. The temperature was set to 280°C, and after 5 minutes, the mixture was removed, cooled, and dried. It was then filled into a mold and preheated in a flat vulcanizer at 280°C for 10 minutes, held at 10 MPa for 5 minutes, and then cold-pressed. After cooling, samples were cut and tested. The flame retardancy grade of the 1.6 mm and 3.2 mm samples was UL94 grade or lower.

[0143] Comparative Example 5 Polyamide PA66, zinc diethylphosphinate, and a composite antioxidant were mixed in a weight ratio of 79.6:20:0.4 in a mixer at a rotation speed of 50 rpm. The temperature was set to 280°C, and after 5 minutes, the mixture was removed, cooled, and dried. It was then filled into a mold and preheated in a flat vulcanizer at 280°C for 10 minutes, held at 10 MPa for 5 minutes, and then cold-pressed. After cooling, samples were cut and tested. The flame retardancy grade of the 1.6 mm and 3.2 mm samples was UL94 grade or lower.

[0144] Comparative Example 6 Polyamide PA66, aluminum dibutylphosphinate prepared in Comparative Example 1, and a composite antioxidant were mixed in a mixer at a weight ratio of 79.6:20:0.4 at a rotation speed of 50 rpm. The temperature was set to 280°C, and after 5 minutes, the mixture was removed, cooled, and dried. The mixture was then filled into a mold, preheated in a flat vulcanizer at 280°C for 10 minutes, held at 10 MPa for 5 minutes, and then cold-pressed. After cooling, samples were cut and tested. Neither the 1.6 mm nor the 3.2 mm samples had a UL94 flame retardancy grade.

[0145] Comparative Example 7 Polyamide PA66, aluminum dihexylphosphinate prepared in Comparative Example 2, and a composite antioxidant were mixed in a weight ratio of 79.6:20:0.4 in a mixer at a rotation speed of 50 rpm. The temperature was set to 280°C, and after 5 minutes, the mixture was removed, cooled, and dried. It was then filled into a mold, preheated in a flat vulcanizer at 280°C for 10 minutes, held at 10 MPa for 5 minutes, and then cold-pressed. After cooling, samples were cut and tested. The flame retardancy grades of the 1.6 mm and 3.2 mm samples were neither UL94 grade nor any other.

[0146] Comparative Example 8 Polyamide PA66, iron dihexylphosphinate prepared in Comparative Example 3, and a composite antioxidant were mixed in a weight ratio of 79.6:20:0.4 in a mixer at a rotation speed of 50 rpm. The temperature was set to 280°C, and after 5 minutes, the mixture was removed, cooled, and dried. It was then filled into a mold, preheated in a flat vulcanizer at 280°C for 10 minutes, held at 10 MPa for 5 minutes, and then cold-pressed. After cooling, samples were cut and tested. The flame retardancy grades of the 1.6 mm and 3.2 mm samples were neither UL94 grade nor any other.

[0147] Comparative Example 9 Polyamide PA66, aluminum diethylphosphinate, aluminum dibutylphosphinate prepared in Comparative Example 1, and a composite antioxidant were mixed in a mixer at a rotation speed of 50 rpm in a weight ratio of 79.6:17.3:2.7:0.4 (where the molar ratio of aluminum diethylphosphinate to aluminum dibutylphosphinate is 9:1). The mixture was then set to a temperature of 280°C, removed after 5 minutes, cooled, and dried. The mixture was then filled into a mold, preheated in a flat vulcanizer at 280°C for 10 minutes, held at 10 MPa for 5 minutes, and then cold-pressed. After cooling, samples were cut and tested. The flame retardancy grade of the 1.6 mm sample was UL94 grade none.

[0148] Comparative Examples 4-8 show that when used individually, aluminum diethylphosphinate, zinc diethylphosphinate, aluminum dibutylphosphinate, aluminum dihexylphosphinate, and iron dihexylphosphinate exhibit low flame retardancy efficiency with respect to polyamides, and Comparative Example 6 shows that it generates a large amount of dust, making it unfavorable to use. Comparative Example 9 shows that if the molar ratio of aluminum diethylphosphinate to aluminum dibutylphosphinate is too high, the flame retardancy efficiency of the composition with respect to polyamides decreases.

[0149] Examples 4-15 demonstrate that the dialkylphosphinate composition described in the present invention exhibits excellent flame retardancy for polyamides, overcoming the drawback of low flame retardancy for polymer materials when diethylphosphinate and long-chain dialkylphosphinate are used individually. During use, Examples 10-12 produced significantly more dust than Examples 4-9, indicating that the co-precipitation composition ratio is more environmentally friendly compared to the physical composition.

[0150] The above description represents only some embodiments of the present invention and does not limit it. While the present invention has been disclosed in the above preferred embodiments, this does not limit it. Modifications or alterations made by those skilled in the art based on the above technical content within the scope of the technical means of the present invention are equivalent to those in the equivalent embodiments and are all included within the scope of the present invention.

Claims

1. A dialkylphosphinate composition, The dialkylphosphinate composition comprises component A and component B, The aforementioned component A is at least one compound selected from compounds having the chemical formula represented by formula (I), The aforementioned component B is at least one compound selected from compounds having the chemical formula represented by formula (II), In the formula, M and N are central atoms, and R １ , R ２ Each is independently C ４ -C １２ Selected from alkyl groups, and R １ , R ２ It is never simultaneously an isobutyl group. M and N are each independently selected from metallic elements, and the metallic element is at least one selected from group IIA, IIIIA, IVA, VA metallic elements, transition metal elements, and lanthanide metallic elements. m and n are the valencies of metals M and N, respectively. m and n are each independently selected from 2, 3, or 4. A dialkylphosphinate composition characterized in that the molar ratio of component A to component B is 1-4.5:4.5-1.

2. The aforementioned Group IIA metallic element is at least one selected from Be, Mg, Ca, Sr, and Ba. The aforementioned Group IIIA metallic element is Al, The aforementioned IVA group metallic element is Sn, The aforementioned VA group metallic element is Sb, The transition metal element is at least one selected from Fe, Zn, Cu, Ti, Zr, and Mn. The dialkylphosphinate composition according to claim 1, characterized in that the lanthanide metal element is Ce.

3. The dialkylphosphinate composition according to claim 1, characterized in that both M and N are Al, and m = n = 3.

4. A method for preparing a dialkylphosphinate composition according to any one of claims 1 to 3, A material containing diethylphosphinic acid and / or its alkali metal salt having the anion in the chemical formula of formula (I), dialkylphosphinic acid and / or its alkali metal salt having the anion in the chemical formula of formula (II), a metal element M source, and a metal element N source is subjected to reaction I in the aqueous phase to obtain the dialkylphosphinate composition, or The dialkylphosphinate composition is obtained by mixing component A and component B. A preparation method characterized in that the component A is selected from the component A described in claim 1, and the component B is selected from the component B described in claim 1.

5. The preparation method according to claim 4, characterized in that the reaction I is carried out under conditions of pH 0-4.

6. The preparation method according to claim 4, characterized in that the conditions for reaction I are a temperature of 0-250°C, a pressure of 0.1 MPa-10 MPa, and a time of 0.01-20 h.

7. The metal element M source is at least one selected from salts of the metal element M. The preparation method according to claim 4, characterized in that the metal element N source is at least one selected from salts of the metal element N.

8. The salt of the metal element M is at least one selected from nitrates, sulfates, hydrochlorides, acetates, and oxides of the metal element M. The preparation method according to claim 7, characterized in that the salt of the metal element N is at least one selected from nitrate, sulfate, hydrochloride, acetate, and oxide of the metal element N.

9. A flame-retardant material containing a flame retardant P and a polyamide, The flame retardant P is characterized in that it is a dialkylphosphinate composition according to any one of claims 1 to 4.

10. The flame retardant material according to claim 9, characterized in that the flame retardant P has a mass content of 1-35% in the flame retardant material.

11. The aforementioned flame-retardant material further contains a functional additive, The functional additive is at least one selected from reinforcing agents, anti-dropping agents, stabilizers, pigments, dyes, dispersants, nucleating agents, inorganic fillers, and antioxidants. The flame retardant material according to claim 9, characterized in that the functional additive is present in a mass content of 5-40% in the flame retardant material.

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