Hydroxyl-containing organic phosphonate as well as preparation method and application thereof

Abstract

The dialkyl phosphinic acid / dialkyl phosphinate is used as the initiator to prepare the organic phosphonate containing hydroxyl, the preparation process is simple, the raw materials are easy to synthesize, the risk of aldol condensation is avoided, the situation that the thermal stability of the flame retardant is reduced by unreacted P-H bonds is avoided, the thermal stability is remarkably improved, the risk of decomposition during high-temperature processing is avoided, and the flame retardant is suitable for industrial production. The phenomenon that the resin is foamed due to release of aldehyde is avoided, and meanwhile, the influence on the machining performance of the resin is small, and the influence on the production environment is low. And the flame-retardant effect is good when the flame-retardant agent is independently used, and the flame-retardant agent has the characteristics of no precipitation, small dosage and high flame-retardant efficiency. Meanwhile, due to the introduction of hydroxyl, the flame retardant has better compatibility with a polar polymer, and meanwhile, the hydroxyl can react with some specific functional groups, so that the compatibility of the flame retardant and resin is improved, the use effect is better when the flame retardant is compounded with other synergistic flame retardants, and the flame retardant can be widely applied to the technical field of flame retardants.

Description

Technical Field

[0001] The invention relates to the technical field of flame retardants, and in particular to an organic phosphonate containing a hydroxyl group and a preparation method and application thereof. Background Art

[0002] The existing organic phosphorus halogen-free flame retardants are mainly aluminum diethylphosphinate (ADP) and phosphate esters, and aluminum diethylphosphinate is the main one in thermoplastic resins / thermosetting resins. ADP itself has average flame retardant properties, and only when it is compounded with other synergistic flame retardants can it have excellent flame retardant properties.

[0003] After the organic phosphorus flame retardant introduces hydroxyl groups, the compatibility of the flame retardant and the resin is improved. However, the existing organic phosphonate flame retardants containing alkylhydroxy groups are synthesized by the reaction of hypophosphorous acid / hypophosphite with aldehyde. After testing, it was found that when aldehyde is used to react with hypophosphorous acid / hypophosphite, an aldehyde condensation reaction is likely to occur, resulting in an increase in aldehyde consumption, and some PH bonds will fail to undergo addition reactions with aldehydes, resulting in low thermal stability of the product, with a 1% thermal weight loss of less than 300°C. This leads to the application scenarios containing alkylhydroxy organic phosphonates, especially in high-temperature scenarios, such as nylon, polyester resin and other resins with higher processing temperatures cannot be used; at the same time, due to the presence of acetal or hemiacetal, aldehyde will be released when the temperature is high, which will also cause foaming of the resin, poor resin processability and the generation of organic waste gas at the production site. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of the above-mentioned technology and provide an organic phosphonate containing a hydroxyl group and a preparation method and application thereof. The preparation method not only makes the raw materials easy to synthesize, but also has no risk of aldol condensation, and no unreacted PH bonds to reduce the thermal stability of the flame retardant.

[0005] To this end, the present invention provides a method for preparing an organic phosphonate containing a hydroxyl group, comprising the following steps:

[0006] (1) reacting a dialkylphosphinic acid / dialkylphosphinic salt solution with a halogen element under ultraviolet light to obtain a halogenated dialkylphosphinic acid / halogenated dialkylphosphinic salt;

[0007] The reaction formula is:

[0008]

[0009] Alternatively, a dialkylphosphinic acid / dialkylphosphinic acid salt solution is reacted with a hydrogen halide or a halogen salt under the action of an oxidant and ultraviolet light to obtain a halogenated dialkylphosphinic acid / halogenated dialkylphosphinic acid salt;

[0010] The reaction formula is:

[0011]

[0012] (2) The halogenated dialkyl phosphinic acid / halogenated dialkyl phosphinic acid salt obtained by the reaction is azeotropically hydrolyzed in an excess of a strong alkali aqueous solution to obtain a hydroxyl-containing organic phosphonate solution, which is then reacted with a soluble salt of the M metal to obtain the hydroxyl-containing organic phosphonate flame retardant.

[0013] The reaction formula is:

[0014]

[0015] Preferably, a method for preparing an organic phosphonate containing a hydroxyl group comprises the following steps:

[0016] (1) reacting a dialkylphosphinic acid / dialkylphosphinic acid salt solution with a halogen element or with a hydrogen halide or a halogen salt and a hypohalite or a perhalide salt under acidic conditions under ultraviolet light to obtain a halogenated dialkylphosphinic acid / halogenated dialkylphosphinic acid salt;

[0017] (2) The halogenated dialkyl phosphinic acid / halogenated dialkyl phosphinic acid salt obtained by the reaction is azeotropically hydrolyzed in an excess of a strong alkali aqueous solution to obtain a hydroxyl-containing organic phosphonate solution, which is then reacted with a soluble salt of the M metal to obtain the hydroxyl-containing organic phosphonate flame retardant.

[0018] More preferably, the halogenate, hypohalite or perhalogenate is the corresponding alkali metal salt thereof.

[0019] Preferably, the halogen element in step (1) is chlorine or bromine, and the halogen salt is any one of the water-soluble metal salts of chlorine or bromine.

[0020] Preferably, the molar ratio of the halogen in the halogen element, hydrogen halide or halogen salt to the phosphorus in the dialkylphosphinic acid / dialkylphosphinic acid salt solution is 1:1-4:1.

[0021] Preferably, the dialkylphosphinic acid / dialkylphosphinic acid salt has the following structure:

[0022]

[0023] Wherein, R3 and R4 are selected from C1-C18 alkyl, cycloalkyl or C7-C18 benzyl structures; n is 1, and N is selected from Group IA metal elements.

[0024] Preferably, the reaction time of step (1) is 0.5-24 hours, and in step (2), the hydrolysis reaction time with the strong alkaline aqueous solution is 0.1-24 hours, and the reaction time with the soluble salt of the M metal is 1-24 hours.

[0025] An organic phosphonate containing an olefin structure is prepared by the method.

[0026] Preferably, the organic phosphonate containing a hydroxyl group has the following structure:

[0027]

[0028] In the structural formula I, R1 and R2 may be the same or different, and at least one of R1 and R2 is a C1-C18 alkyl, cycloalkyl or C7-C18 benzyl structure containing not less than one hydroxyl group; m is an integer of 2-4; and M is a metal element of Groups ⅡA-ⅢA and transition metals ⅢB and IVB.

[0029] Preferably, R1 and R2 are selected from any one of hydroxymethyl, hydroxyethyl, hydroxypropyl, hydroxybutyl, 2-hydroxy-2-phenyl-ethyl, 3-hydroxy-3-phenyl-propyl, 3-hydroxy-2 phenyl-isopropyl, 3-hydroxy-1-cyclopentyl, 2-hydroxy-1-cyclopentyl, 2-hydroxy-1-cyclohexyl, 3-hydroxy-1-cyclohexyl, methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopentyl, cyclohexyl, octyl, phenethyl, and naphthylethyl, and at least one of R1 and R2 is a functional group containing a hydroxyl group.

[0030] Preferably, M is any one of calcium, magnesium, aluminum, zinc, copper, iron, gallium, vanadium, nickel, cobalt, lanthanum, samarium, and rhodium.

[0031] Preferably, when dialkyl hypophosphorous acid or dialkyl hypophosphite is used as the initiator, the dialkyl phosphinic acid / dialkyl phosphite is selected from any one of dimethyl phosphinic acid, dimethyl phosphinic acid alkali metal salt, methyl ethyl phosphinic acid, methyl ethyl phosphinic acid alkali metal salt, methyl propyl phosphinic acid, methyl propyl phosphinic acid alkali metal salt, methyl isopropyl phosphinic acid, methyl isopropyl phosphinic acid alkali metal salt, methyl (1-butyl) phosphinic acid, methyl isobutyl phosphinic acid, methyl isobutyl phosphinic acid alkali metal salt, methyl benzyl phosphinic acid, methyl benzyl phosphinic acid alkali metal salt, diethyl phosphinic acid, diethyl phosphinic acid alkali metal salt, ethyl butyl phosphinic acid, ethyl butyl phosphinic acid alkali metal salt, ethyl cyclohexyl phosphinic acid alkali metal salt, ethyl cyclopentyl phosphinic acid, ethyl cyclopentyl hypophosphite alkali metal salt, dicyclopentyl phosphinic acid, and dicyclopentyl hypophosphite alkali metal salt.

[0032] Preferably, the soluble salt of the M metal is selected from the sulfate or nitrate of the metal.

[0033] The above-mentioned organic phosphonate containing hydroxyl group can be compounded with red phosphorus flame retardant, organic phosphorus flame retardant, silicon flame retardant, phosphorus silicon flame retardant, nitrogen flame retardant, phosphorus nitrogen flame retardant and boron flame retardant for synergistic use.

[0034] The above organic phosphonate containing hydroxyl group can be added into thermoplastic resin or thermosetting resin or thermoplastic reinforced resin or thermosetting reinforced resin or fiber or film in an amount of 1%-50% to provide flame retardant property thereto.

[0035] Preferably, the thermoplastic reinforcing resin is selected from at least one of thermoplastic polyurethane (TPU), thermoplastic elastomer (TPE), polyolefin elastomer (TPE-O), dynamic vulcanized rubber (TPV), polyamide (PA), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyolefin.

[0036] Preferably, the thermosetting reinforcing resin is selected from at least one of epoxy resin, silicone resin, saturated polyester resin, unsaturated polyester resin, thermosetting polyurethane and thermosetting acrylic resin.

[0037] Preferably, the fiber reinforcement material is selected from any one of glass fiber, basalt fiber, whisker, carbon fiber, aramid fiber, ultra-high molecular weight polyethylene fiber, and rock wool fiber.

[0038] Preferably, the organophosphorus flame retardant is selected from at least one of aluminum diethylphosphinate (ADP), zinc diethylphosphinate (ZDP), calcium diethylphosphinate, iron diethylphosphinate, nickel diethylphosphinate, magnesium diethylphosphinate, aluminum methylethylphosphinate, zinc methylethylphosphinate, aluminum methylphosphate, zinc methylphosphinate, iron methylphosphinate, nickel methylphosphinate, lanthanum methylphosphinate, aluminum diethylphosphinate ethylphosphinate (MADP), calcium diethylphosphinate ethylphosphinate, magnesium diethylphosphinate ethylphosphinate, zinc diethylphosphinate ethylphosphinate, nickel diethylphosphinate ethylphosphinate, lanthanum diethylphosphinate ethylphosphinate, aluminum ethylphosphinate, zinc ethylphosphinate, iron ethylphosphinate, and magnesium ethylphosphinate.

[0039] Preferably, the silicon-based flame retardant is selected from phenyl silicone resin.

[0040] Preferably, the phosphorus-silicon flame retardant is selected from copolymers or blends of organic phosphorus and organic silicon.

[0041] Preferably, the nitrogen-based flame retardant is selected from any one of melamine salt, ammonium polyacrylate and ammonium polymethacrylate.

[0042] Preferably, the phosphorus-nitrogen flame retardant is selected from polyphosphate melamine salt and ammonium polyphosphate.

[0043] Preferably, the boron-based flame retardant is selected from zinc borate and its hydrate.

[0044] The present invention provides an organic phosphonate containing a hydroxyl group and a preparation method and application thereof, which have the following beneficial effects:

[0045] (1) The preparation process of the present invention is simple, the raw materials are easy to synthesize, and there is no risk of aldol condensation, and there is no unreacted PH bond to reduce the thermal stability of the flame retardant. The thermal stability is significantly improved, there is no risk of decomposition during high-temperature processing, and no aldehyde release will occur to cause the resin to foam. At the same time, the mechanical processing performance of the resin is slightly affected, and the impact on the production environment is low.

[0046] (2) The hydroxyl-containing organic phosphate prepared by the present invention can also remain in the emulsion without breaking, has little effect on adhesion, and can pass the hundred-grid test.

[0047] (3) The organic phosphate containing hydroxyl prepared by the present invention has a good flame retardant effect when used alone without compounding. It has good flame retardancy in nylon and polyester resins, and has the characteristics of no precipitation, small amount and high flame retardant efficiency. At the same time, due to the introduction of hydroxyl groups, the flame retardant has better compatibility with polar polymers. At the same time, hydroxyl groups can also react with some specific functional groups, such as transesterification with ester groups and addition reaction with isocyanates, which improves the compatibility of flame retardants with resins, making it more effective when used in combination with other synergistic flame retardants. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a comparison diagram of infrared spectra of the hydroxy salt flame retardant prepared by the present invention and diethyl aluminum phosphinate.

[0049] Figure 2 It is a thermogravimetric comparison curve of the hydroxy salt flame retardant prepared in Example 4 of the present invention and the organic phosphate synthesized using acetaldehyde. DETAILED DESCRIPTION

[0050] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments to help understand the content of the present invention. The methods used in the present invention are all conventional methods unless otherwise specified; the raw materials and devices used are all conventional commercial products unless otherwise specified.

[0051] Example 1

[0052] Dissolve 1 mol of dimethylphosphinic acid in 1L deionized water, add 0.1 mol of sodium bromide, transfer to a 5L four-necked flask, and raise the temperature to 60°C. At the same time, dissolve 1 mol of sodium hypobromite in 1L water, use a peristaltic pump to drop the sodium hypobromite aqueous solution into the dimethylphosphinic acid mixed solution at a rate of 6 hours, and use ultraviolet light to irradiate the four-necked flask to accelerate the reaction. Continue to react for 2 hours after the addition is completed, remove the ultraviolet light lamp after the reaction is completed, and use sodium hydroxide to neutralize first, then add 1.5 mol of sodium hydroxide, and boil and reflux the solution for 6 hours. After the reflux is completed, reduce the temperature to 40°C, use a peristaltic pump to drop a 20% aqueous solution containing 0.33 mol of aluminum sulfate into the four-necked flask at a rate of 8 hours. After the addition is completed, continue stirring for 2 hours, filter, wash, dry and crush to obtain hydroxymethyl methyl phosphinate aluminum flame retardant.

[0053] Example 2

[0054] Dissolve 1 mol of methylethylphosphinic acid in 1L deionized water, add 1 mol of sodium bromide, transfer to a 5L four-necked flask, and raise the temperature to 60°C. At the same time, dissolve 0.2 mol of potassium permanganate in 1L of water, use a peristaltic pump to drop the potassium permanganate aqueous solution into the methylethylphosphinic acid mixed solution at a rate of 6 hours, and use ultraviolet light to irradiate the four-necked flask to accelerate the reaction. After the addition is completed, continue to react for 4 hours, remove the ultraviolet light lamp after the reaction is completed, and use sodium hydroxide to neutralize first, then add 1.5 mol of sodium hydroxide, and boil and reflux the solution for 6 hours. After the reflux is completed, reduce the temperature to 40°C, and use a peristaltic pump to drop a 20% aqueous solution containing 0.33 mol of aluminum sulfate into the four-necked flask at a rate of 8 hours. Continue stirring for 2 hours after the addition is completed, filter, wash, dry and crush to obtain hydroxymethylethylphosphinic acid aluminum flame retardant.

[0055] Example 3

[0056] Dissolve 1 mol of methylethylphosphinic acid in 1L deionized water, add 1 mol of sodium bromide, transfer to a 5L four-necked flask, and raise the temperature to 60°C. At the same time, dissolve 0.2 mol of potassium permanganate in 1L of water, use a peristaltic pump to drop the potassium permanganate aqueous solution into the methylethylphosphinic acid mixed solution at a rate of 6 hours, and use ultraviolet light to irradiate the four-necked flask to accelerate the reaction. After the addition is completed, continue to react for 4 hours, remove the ultraviolet light after the reaction is completed, and use sodium hydroxide to neutralize first, then add 1.5 mol of sodium hydroxide, and boil and reflux the solution for 6 hours. After the reflux is completed, reduce the temperature to 60°C, and use a peristaltic pump to drop a 20% aqueous solution containing 0.33 mol of aluminum sulfate into the four-necked flask at a rate of 0.1 hours. After the addition is completed, filter, wash, dry and crush to obtain a hydroxymethylethylphosphinic acid aluminum flame retardant.

[0057] Example 4

[0058] 1mol of methylpropylphosphinic acid was dissolved in 1.5L deionized water, 10g of 37% concentrated hydrochloric acid was added, and the mixture was transferred to a 5L four-necked flask, and the temperature was raised to 40°C. At the same time, 2mol of sodium hypobromite was dissolved in 1L water, and a peristaltic pump was used to drop an aqueous solution of sodium hypobromite into the methylpropylphosphinic acid mixed solution at a speed of 8 hours of dropwise addition, and a four-necked flask was irradiated with ultraviolet light to accelerate the reaction. After the dropwise addition was completed, the reaction was continued for 1 hour, and the ultraviolet light was removed and sodium hydroxide was used to neutralize the mixture first, and then 3.5mol of sodium hydroxide was added, and the solution was boiled and refluxed for 6 hours. After the reflux was completed, the temperature was lowered to 40°C, and a 20% aqueous solution containing 0.33mol of aluminum sulfate was added to the four-necked flask at a speed of 8 hours of dropwise addition. After the dropwise addition was completed, stirring was continued for 2 hours, and the 2-hydroxypropyl hydroxymethyl phosphinic acid aluminum flame retardant was obtained by filtering, washing, drying and crushing.

[0059] Example 5

[0060] Dissolve 1 mol of methylpropylphosphinic acid in 1.5L deionized water, pass 1 mol of chlorine gas within 4 hours, and use ultraviolet light to irradiate the four-necked flask to accelerate the reaction. Continue to react for 1 hour after the addition of chlorine. After the reaction is completed, remove the ultraviolet light and use sodium hydroxide to neutralize it first, then add 3.5 mol of sodium hydroxide, and boil and reflux the solution for 6 hours. After the reflux is completed, lower the temperature to 40°C, and use a peristaltic pump to drip a 20% aqueous solution containing 0.33 mol of aluminum sulfate into the four-necked flask at a speed of 8 hours. Continue stirring for 2 hours after the addition is completed, filter, wash, dry and crush to obtain 2-hydroxypropyl hydroxymethyl aluminum phosphinic acid flame retardant.

[0061] Example 6

[0062] Dissolve 1 mol of diethylphosphinic acid in 1.5L deionized water, add 1 mol of hydrogen bromide, and transfer to a 5L four-necked flask. At the same time, dissolve 1 mol of hydrogen peroxide in 1L water, use a peristaltic pump to drop the hydrogen peroxide solution into the diethylphosphinic acid aqueous solution at a speed of 6 hours, and use ultraviolet light to irradiate the four-necked flask to accelerate the reaction. After the addition is completed, continue to react for 8 hours, remove the ultraviolet light lamp after the reaction is completed, and use sodium hydroxide to neutralize first, then add 1.1 mol of sodium hydroxide, and boil the solution at reflux for 12 hours. After the reflux is completed, use a peristaltic pump to drop a 20% aqueous solution containing 0.33 mol of aluminum sulfate into the four-necked flask at a speed of 10 hours. Continue stirring for 2 hours after the addition is completed, filter, wash, dry and crush to obtain hydroxyethyl ethyl phosphinate aluminum flame retardant.

[0063] Example 7

[0064] 1mol of methylphenylphosphinic acid was dissolved in 1.5L deionized water, 1mol of hydrogen bromide was added, and transferred to a 5L four-necked flask. At the same time, 1mol of hydrogen peroxide was dissolved in 1L of water, and a peristaltic pump was used to drop the hydrogen peroxide solution into the methylphenylphosphinic acid mixed solution at a speed of 6 hours of dropwise addition, and ultraviolet light was used to irradiate the four-necked flask to accelerate the reaction. After the addition was completed, the reaction continued for 8 hours, and after the reaction was completed, the ultraviolet light was removed and sodium hydroxide was used to neutralize it first, and then 1mol of sodium hydroxide was added, and the solution was boiled and refluxed for 12 hours. After the reflux was completed, a 20% aqueous solution containing 0.33mol of ferric sulfate was added dropwise to the four-necked flask at a speed of 10 hours of dropwise addition. After the addition was completed, stirring was continued for 2 hours, and the hydroxymethylphenylphosphinic acid iron flame retardant was obtained by filtering, washing, drying and crushing.

[0065] Example 8

[0066] 1 mol of methylphenylphosphinic acid was dissolved in 1.5L deionized water, 1 mol of hydrogen bromide was added, and transferred to a 5L four-necked flask. At the same time, 1 mol of hydrogen peroxide was dissolved in 1L of water, and a peristaltic pump was used to drop the hydrogen peroxide solution into the methylphenylphosphinic acid mixed solution at a speed of 6 hours of dropwise addition, and ultraviolet light was used to irradiate the four-necked flask to accelerate the reaction. After the dropwise addition was completed, the reaction was continued for 8 hours, and after the reaction was completed, the ultraviolet light was removed and sodium hydroxide was used to neutralize it first, and then 1 mol of sodium hydroxide was added, and the solution was boiled and refluxed for 12 hours. After the reflux was completed, a 20% aqueous solution containing 0.5 mol of zinc sulfate was added dropwise to the four-necked flask at a speed of 10 hours of dropwise addition. After the dropwise addition was completed, stirring was continued for 2 hours, and the hydroxymethylphenylphosphinic acid zinc flame retardant was obtained by filtering, washing, drying and crushing.

[0067] Example 9

[0068] 1 mol of ethylcyclohexylphosphinic acid was dissolved in 1.5L deionized water, 1 mol of hydrogen bromide was added, and the mixture was transferred to a 5L four-necked flask. At the same time, 1 mol of hydrogen peroxide was dissolved in 1L of water, and a peristaltic pump was used to drop the hydrogen peroxide solution into the ethylcyclohexylphosphinic acid mixed solution at a speed of 6 hours of dropwise addition, and ultraviolet light was used to irradiate the four-necked flask to accelerate the reaction. After the dropwise addition was completed, the reaction was continued for 8 hours, and after the reaction was completed, the ultraviolet light was removed and sodium hydroxide was used to neutralize it first, and then 1 mol of sodium hydroxide was added, and the solution was boiled and refluxed for 12 hours. After the reflux was completed, a 20% aqueous solution containing 0.33 mol of nickel nitrate was added to the four-necked flask at a speed of 10 hours of dropwise addition. After the dropwise addition was completed, stirring was continued for 2 hours, and the hydroxyethylcyclohexylphosphinic acid nickel flame retardant was obtained by filtering, washing, drying and crushing.

[0069] Example 10

[0070] 1mol of sodium ethyl isopropyl phosphinate was dissolved in 1.5L deionized water, 4mol of hydrogen chloride was added, and the mixture was transferred to a 5L four-necked flask. Meanwhile, 4mol of hydrogen peroxide was dissolved in 1L of water, and a peristaltic pump was used to drop the hydrogen peroxide solution into the mixed solution of sodium ethyl isopropyl phosphinate at a speed of 6 hours of dropwise addition, and a four-necked flask was irradiated with ultraviolet light to accelerate the reaction. After the dropwise addition was completed, the reaction was continued for 8 hours, and after the reaction was completed, the ultraviolet light was removed and sodium hydroxide was used to neutralize the mixture, and then 1mol of sodium hydroxide was added, and the solution was boiled and refluxed for 12 hours. After the reflux was completed, a 20% aqueous solution containing 0.33mol of cobalt nitrate was added to the four-necked flask at a speed of 10 hours of dropwise addition. After the dropwise addition was completed, stirring was continued for 2 hours, and 1,2-dihydroxyethyl-1,2-dihydroxyisopropylphosphinate cobalt flame retardant was obtained by filtering, washing, drying and crushing.

[0071] Example 11 Group

[0072] The hydroxymethyl ethyl phosphinate aluminum flame retardant obtained in Example 2 was blended and extruded with PA66, with the flame retardant accounting for 13wt%, to obtain non-reinforced flame retardant PA66, and the performance data are shown in Table 1; it meets the UL94-V0@1.6mm flame retardant grade.

[0073] Example 12 Group

[0074] The hydroxymethyl ethyl phosphinate aluminum flame retardant obtained in Example 2 was blended with PA66 and glass fiber and extruded, with the flame retardant accounting for 15wt% and the glass fiber accounting for 30wt%, to obtain enhanced flame retardant PA66, and the performance data are shown in Table 1; it meets the UL94-V0@1.6mm flame retardant rating.

[0075] Example 13 Group

[0076] The 2-hydroxypropyl hydroxymethyl aluminum phosphinate flame retardant obtained in Example 4 was mixed with a polyol in a weight ratio of 1:1, and then reacted with an equivalent amount of isocyanate to obtain a thermosetting flame retardant polyurethane. The performance data are shown in Table 1; it meets the UL94-V0@1.6mm flame retardant rating.

[0077] Example 14 Group

[0078] The 2-hydroxypropyl hydroxymethyl aluminum phosphinate flame retardant obtained in Example 4 was mixed with 50% acrylic emulsion in an addition amount of 20%. The performance data after drying are shown in Table 1.

[0079] Comparative Example 1

[0080] 1 mol of sodium hypophosphite was dissolved in 1 L of deionized water, and then 2 mol of acetaldehyde was added and transferred to a 5 L four-necked flask, heated to 80 ° C and refluxed, 10-3 mol of ammonium persulfate was added in batches to initiate the reaction, and the reaction was carried out for 6 hours. After the reaction, a peristaltic pump was used to add a 50% aqueous solution of aluminum sulfate containing 0.33 mol, and the addition time was 6 hours. After the addition was completed, the reaction was continued for 2 hours, and then filtered, washed and dried to obtain dihydroxyethyl aluminum phosphinate. The performance data are shown in Table 1.

[0081] Comparative Example 2

[0082] Compared with Example 14, the dihydroxyethyl aluminum phosphinate obtained in Comparative Example 1 was mixed with 50% acrylic emulsion and added in an amount of 20%, which directly caused the acrylic emulsion to demulsify and could not be used further. The performance data are shown in Table 1.

[0083] Comparative Example 3

[0084] Compared with Example 12, the aluminum dihydroxyethyl phosphinate obtained in Comparative Example 1 was blended and extruded with PA66 and glass fiber, with the flame retardant accounting for 15wt% and the glass fiber accounting for 30wt% to obtain enhanced flame retardant PA66. The performance data are shown in Table 1; the flame retardant rating of UL94-V0@1.6mm is not reached.

[0085] In the accompanying drawings, Figure 1 It is a comparison diagram of infrared spectra of the hydroxy salt flame retardant prepared by the present invention and diethyl phosphinate aluminum, and neither shows the infrared characteristic peak of the PH bond. Figure 2 It is a thermogravimetric comparison curve of the hydroxy salt flame retardant prepared in Example 4 of the present invention and the organic phosphate synthesized using acetaldehyde.

[0086] The experimental performance comparison is as follows:

[0087] Table 1

[0088]

[0089] The experimental results show that the 1% thermal weight loss temperature of the organic phosphate synthesized by acetaldehyde is only 270°C, while the 1% thermal weight loss temperature of the organic phosphate containing hydroxyl prepared by the present invention is about 410°C, and the thermal stability is significantly improved. The organic phosphate containing hydroxyl prepared by the present invention can also remain in the emulsion without demulsification, has little effect on adhesion, and can pass the Baige test. In addition, the organic phosphate containing hydroxyl prepared by the present invention has a good flame retardant effect when used alone without compounding, has good flame retardancy in nylon and polyester resins, and the organic phosphate containing hydroxyl has the characteristics of no precipitation, small dosage, and high flame retardant efficiency. At the same time, due to the introduction of hydroxyl, the flame retardant has better compatibility with polar polymers. At the same time, the hydroxyl can also react with some specific functional groups, such as transesterification reaction with ester groups and addition reaction with isocyanate, which improves the compatibility of the flame retardant with the resin, so that it can be used in combination with other synergistic flame retardants for better effect.

[0090] In summary, the preparation process of the present invention is simple, the raw materials are easy to synthesize, there is no risk of aldol condensation, and there is no unreacted PH bond to reduce the thermal stability of the flame retardant. There is no risk of decomposition during high-temperature processing, and no aldehyde release will cause the resin to foam. At the same time, the mechanical processing performance of the resin is slightly affected, and the impact on the production environment is low.

[0091] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement modes and shall be included in the protection scope of the present invention.

Claims

1. A method for preparing an organic phosphonate containing a hydroxyl group, characterized in that: The following steps are involved: (1) reacting a dialkyl phosphinic acid / dialkyl phosphinic salt solution with a halogen element under ultraviolet light to obtain a halogenated dialkyl phosphinic acid / halogenated dialkyl phosphinic salt; Alternatively, a dialkylphosphinic acid / dialkylphosphinic acid salt solution is reacted with a hydrogen halide or a halogen salt under the action of an oxidant and ultraviolet light to obtain a halogenated dialkylphosphinic acid / halogenated dialkylphosphinic acid salt; (2) The halogenated dialkyl phosphinic acid / halogenated dialkyl phosphinic acid salt obtained by the reaction is azeotropically hydrolyzed in an excess of a strong alkali aqueous solution to obtain a hydroxyl-containing organic phosphonate solution, which is then reacted with a soluble salt of the M metal to obtain the hydroxyl-containing organic phosphonate.

2. The method for preparing an organic phosphonate containing a hydroxyl group according to claim 1, characterized in that: In step (1), the halogen element is chlorine or bromine, and the halogen salt is any one of the water-soluble metal salts of chlorine or bromine.

3. The method for preparing an organic phosphonate containing a hydroxyl group according to claim 1, characterized in that: The molar ratio of the halogen in the halogen element, hydrogen halide or halogen salt to the phosphorus in the dihydrocarbylphosphinic acid / dihydrocarbylphosphinic acid salt solution is 1:1-4:

1.

4. The method for preparing an organic phosphonate containing a hydroxyl group according to claim 1, characterized in that: Dialkylphosphinic acid / dialkylphosphinic acid salt has the following structure: Wherein, R3 and R4 are selected from C1-C18 alkyl, cycloalkyl or C7-C18 benzyl structures; n is 1, and N is selected from Group IA metal elements.

5. The method for preparing an organic phosphonate containing a hydroxyl group according to claim 1, characterized in that: The reaction time of step (1) is 0.5-24 hours. In step (2), the hydrolysis reaction time with the strong alkaline aqueous solution is 0.1-24 hours, and the reaction time with the soluble salt of the M metal is 1-24 hours.

6. An organic phosphonate containing a hydroxyl group, characterized in that: The organic phosphonate containing hydroxyl group is prepared by the method according to any one of claims 1 to 5.

7. An organic phosphonate containing a hydroxyl group according to claim 6, characterized in that: The organic phosphonate containing a hydroxyl group has the following structure: In the structural formula I, R1 and R2 may be the same or different, and at least one of R1 and R2 is a C1-C18 alkyl, cycloalkyl or C7-C18 benzyl structure containing not less than one hydroxyl group; m is an integer of 2-4; and M is a metal element of Groups ⅡA-ⅢA and transition metals ⅢB and IVB.

8. An application of an organic phosphonate containing a hydroxyl group, characterized in that: The hydroxyl-containing organic phosphonate described in any one of claims 1 to 7 can be compounded and used synergistically with red phosphorus flame retardants, organic phosphorus flame retardants, silicon flame retardants, phosphorus silicon flame retardants, nitrogen flame retardants, phosphorus nitrogen flame retardants, and boron flame retardants.

9. An application of an organic phosphonate containing a hydroxyl group, characterized in that: The organic phosphonate containing hydroxyl groups as claimed in any one of claims 1 to 7 can be added to thermoplastic resins, thermosetting resins, thermoplastic reinforced resins, thermosetting reinforced resins, fibers or films in an amount of 1% to 50% to provide flame retardant properties thereto.

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