Particle size-adjusted alkyl hypophosphite flame retardant and its manufacturing method

Abstract

The present invention relates to a hypophosphite flame retardant and a method for producing the same, and more particularly to a method for producing a particle-size-adjusted hypophosphite flame retardant by supplying a divalent to tetravalent metal salt through a nozzle. The particle-size-adjusted hypophosphite flame retardant of the present invention can impart excellent flame retardancy to adhesive compositions that require a thin thickness and flame-retardant compositions that require heat resistance, without impairing the physical properties of the product.

Description

[Technical Field]

[0001] The present invention relates to a hypophosphite flame retardant and a method for producing the same, and more particularly to a method for producing a particle-size-controlled hypophosphite flame retardant, which includes a step of supplying at least one raw material selected from alkyl hypophosphite metal salts and divalent to tetravalent metal salts via a nozzle, and to the particle-size-controlled hypophosphite flame retardant produced thereby. [Background technology]

[0002] Polymeric materials play an important role in human life. However, most thermoplastic polymeric materials are highly flammable, posing a fire hazard, and the need for flame retardants has long been growing. Traditionally, flame retardants have been achieved using halogen-based compounds containing bromine or chlorine, which offer excellent flame retardancy and heat resistance. Halogen-based flame retardants are widely used today due to their excellent flame retardancy. However, they are toxic to both humans and the environment because they emit toxic combustion gases and dioxins. Therefore, restrictions on the use of halogenated flame retardants have been tightened, particularly in Europe, and there is a strong demand for flame retardants with performance comparable to that of halogenated flame retardants.

[0003] Phosphorus-based compounds have been attracting attention as alternatives to halogen flame retardants, and research into them is being actively conducted. However, they have limitations, such as being significantly inferior to halogen-based compounds in terms of flame retardancy and heat resistance.

[0004] It goes without saying that flame retardants must have excellent flame retardancy and heat resistance. Depending on the application and environment, the particle size of the flame retardant can play a very important role. For example, adhesives used in flexible flat cables (FFCs), a type of electronic material, typically have a thickness of 40 μm or less, making it difficult to use flame retardants with large particle sizes. However, when flame retardants are blended with the materials used in electronic or automotive components, if the particle size of the flame retardant used is small, its apparent specific gravity will be low, forming bridges in the feeding hopper and preventing smooth feeding, leading to product defects.

[0005] In order to provide flame retardants with particle sizes suitable for such applications, various particle size adjustment methods have been proposed. For example, a method of adjusting the particle size of hypophosphite flame retardants using ultrasound has been proposed. However, the particle size of flame retardants produced by such particle size adjustment methods is too small. While suitable for adhesives, this method poses problems for use in compounds, limiting their application fields.

[0006] Therefore, there is a need for the development of a flame retardant that can replace halogen-based flame retardants, can easily adjust particle size to various sizes, and can provide a flame retardant with excellent flame retardancy in various fields. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Korean Patent Registration No. 10-2095283 [Patent Document 2] Korean Patent Publication No. 10-2019-0055821 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a hypophosphite-based flame retardant having an adjusted particle size distribution so as to impart excellent flame retardancy to articles for various uses without impairing the physical properties of the products containing the flame retardant.

[0009] An object of the present invention is to provide a hypophosphite-based flame retardant that is advantageous for various applications, such as adhesive compositions that require a thin thickness or flame-retardant compositions that require heat resistance.

[0010] Another object of the present invention is to provide a method for producing a hypophosphite-based flame retardant having excellent flame retardancy in a simple and economical manner. [Means for solving the problem]

[0011] In order to achieve the above object, the present invention provides a hypophosphite-based flame retardant that satisfies the following formulas 1 and 2 and is represented by the following chemical formula 1.

[0012] [Formula 1]0.1 <D 50 / (D 98 -D 50 )<0.6

[0013] [Formula 2] 250℃ <T CG <320℃

[0014] [Chemical formula 1] JPEG2026504902000002.jpg3159

[0015] In the above formula 1, when measured by a laser diffraction scattering method, the particle size corresponding to 50% of the cumulative volume of the particle size distribution is D 50 The particle size corresponding to 98% of the cumulative volume of the particle size distribution is D 98 is.

[0016] In the above formula 2, TCG means the first temperature at which a weight loss of 1.0% occurs under thermogravimetric analysis conditions of a heating rate of 10° C. / min and a nitrogen flow rate of 20 ml / min.

[0017] In the above Chemical Formula 1, R1 and R2 are hydrogen or, independently of each other, linear or branched (C1-C6) alkyl; M is a metal atom of Ca, Mg, Al, Zn, or Ti; and n is an integer selected from 2 to 4.

[0018] In one embodiment of the present invention, the hypophosphite-based flame retardant may satisfy the following formula 3:

[0019] [Formula 3]0.1 <D 50 / (D 98 -D 50 )<0.3

[0020] In the above formula 3, when measured by a laser diffraction scattering method, the particle size corresponding to 50% of the cumulative volume of the particle size distribution is D 50 The particle size corresponding to 98% of the cumulative volume of the particle size distribution is D 98 is.

[0021] In one embodiment of the present invention, the hypophosphite-based flame retardant may satisfy the following formulas 5 and 6:

[0022] [Formula 5] 0.35 <D 50 / (D 98 -D 50 )<0.6

[0023] [Formula 6] 290℃ <T CG <320℃

[0024] In the above formula 5, when measured by a laser diffraction scattering method, the particle size corresponding to 50% of the cumulative volume of the particle size distribution is D 50 The particle size corresponding to 98% of the cumulative volume of the particle size distribution is D 98 is.

[0025] In the above formula 6, T CG means the first temperature at which a weight loss of 1.0% occurs under thermogravimetric analysis conditions of a heating rate of 10°C / min and a nitrogen flow rate of 20 ml / min.

[0026] In one embodiment of the present invention, the flame retardant D 50 may be 30 μm or less.

[0027] In one embodiment of the present invention, the flame retardant D 98 may be 100 μm or less.

[0028] Another aspect of the present invention relates to a method for producing a hypophosphite-based flame retardant, comprising the steps of: a) stirring an alkali metal hypophosphite, a (C2-C4) alkene, a radical initiator, and water to produce an alkyl metal hypophosphite; b) reacting the alkyl metal hypophosphite produced in step a) with a divalent, trivalent, or tetravalent metal salt to produce a hypophosphite-based metal salt; c) washing the hypophosphite-based metal salt produced in step b) with distilled water; and d) drying the hypophosphite-based metal salt washed in step c) under vacuum conditions to produce a hypophosphite-based flame retardant represented by the following chemical formula 1, wherein in step b), at least one of the alkyl metal hypophosphite and the divalent, trivalent, or tetravalent metal salt is supplied via a nozzle.

[0029] [Chemical formula 1] JPEG2026504902000003.jpg3159

[0030] In the above Chemical Formula 1, R1 and R2 are hydrogen or, independently of each other, linear or branched (C1-C6) alkyl; M is a metal atom of Ca, Mg, Al, Zn, or Ti; and n is an integer selected from 2 to 4.

[0031] In one embodiment of the present invention, the method for producing a hypophosphite-based flame retardant may be such that the nozzle is a straight nozzle, a full cone nozzle, or a spray nozzle.

[0032] In one embodiment of the present invention, the method for producing a hypophosphite-based flame retardant may be such that raw materials are supplied through a straight nozzle and the flame retardant satisfies the following formula 3:

[0033] [Formula 3]0.1 <D 50 / (D 98 -D 50 )<0.3

[0034] In the above formula 3, when measured by a laser diffraction scattering method, the particle size corresponding to 50% of the cumulative volume of the particle size distribution is D 50 The particle size corresponding to 98% of the cumulative volume of the particle size distribution is D 98 is.

[0035] In one embodiment of the present invention, the method for producing a hypophosphite-based flame retardant may be such that raw materials are supplied through a full cone nozzle or a spray nozzle, and the flame retardant satisfies the following formulas 5 and 6.

[0036] [Formula 5]0.35 <D 50 / (D 98 -D 50 )<0.6

[0037] [Formula 6]290℃ <T CG <320℃

[0038] In the above formula 5, when measured by a laser diffraction scattering method, the particle size corresponding to 50% of the cumulative volume of the particle size distribution is D 50 The particle size corresponding to 98% of the cumulative volume of the particle size distribution is D 98 is.

[0039] In the above formula 6, T CG means the first temperature at which a weight loss of 1.0% occurs under thermogravimetric analysis conditions of a heating rate of 10°C / min and a nitrogen flow rate of 20 ml / min.

[0040] One embodiment of the present invention may be a method for producing a hypophosphite flame retardant, wherein the salt of a divalent to tetravalent metal is a hydrochloride, sulfate, or nitrate of a divalent to tetravalent metal.

[0041] One embodiment of the present invention may be a method for producing a hypophosphite flame retardant, wherein the reaction temperature in step b) is 60°C or lower.

[0042] Yet another aspect of the present invention relates to an adhesive composition comprising the above-mentioned hypophosphite-based flame retardant and an adhesive polymer, wherein the hypophosphite-based flame retardant satisfies the following formula 3:

[0043] [Formula 3]0.1 <D 50 / (D 98 -D 50 )<0.3

[0044] In the above formula 3, when measured by a laser diffraction scattering method, the particle size corresponding to 50% of the cumulative volume of the particle size distribution is D 50 The particle size corresponding to 98% of the cumulative volume of the particle size distribution is D 98 is.

[0045] In one embodiment of the present invention, the adhesive composition may be for use with a CCL (Copper Clad Laminate) or an FFC (Flexible Flat Cable).

[0046] Another aspect of the present invention relates to a flame-retardant composition comprising the aforementioned hypophosphite-based flame retardant and a resin, wherein the flame retardant satisfies the following formulas 5 and 6:

[0047] [Formula 5]0.35 <D 50 / (D 98 -D 50 )<0.6

[0048] [Formula 6]290℃ <T CG <320℃

[0049] In the above formula 5, when measured by a laser diffraction scattering method, the particle size corresponding to 50% of the cumulative volume of the particle size distribution is D 50 The particle size corresponding to 98% of the cumulative volume of the particle size distribution is D 98 is.

[0050] In the above formula 6, T CG means the first temperature at which a weight loss of 1.0% occurs under thermogravimetric analysis conditions of a heating rate of 10°C / min and a nitrogen flow rate of 20 ml / min.

[0051] In one embodiment of the present invention, the resin may be polybutylene terephthalate, polyethylene terephthalate, polybutalamide, or nylon 6,6. [Effects of the Invention]

[0052] The particle size-adjusted hypophosphite-based flame retardant according to the present invention can impart excellent flame retardancy to adhesive compositions that require a thin thickness and flame-retardant compositions that require heat resistance, without impairing the physical properties of the products.

[0053] The method for producing a hypophosphite-based flame retardant according to the present invention makes it easy to adjust the particle size of the hypophosphite-based flame retardant, and enables the production of a hypophosphite-based metal salt flame retardant having excellent flame retardancy in a simple and economical manner.

[0054] Since the present invention does not use organic solvents such as acetic acid, it can solve the problems of corrosion of the reactor and the problem of an unpleasant odor caused by organic solvents such as acetic acid remaining in the product. [Brief explanation of the drawings]

[0055] [Figure 1] 1 shows the results of 1H NMR measurement of sodium diethylphosphinate (SDP) produced in a production example of the present invention (600 MHz, DO solvent). [Figure 2] FIG. 1 is a schematic diagram of a batch reactor used in the production method of the present invention. [Figure 3] FIG. 1 is a schematic diagram of a continuous reactor used in the production method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0056] In the following, an example will be described to more specifically explain the present invention, but the present invention is not limited to the following example. In explaining the present invention, detailed descriptions of related publicly known functions or configurations will be omitted to avoid obscuring the gist of the present invention.

[0057] The embodiments of the inventive concepts may be variously modified and may have various forms, and it is not intended to limit the embodiments of the inventive concepts to the particular forms disclosed, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

[0058] Unless otherwise defined in the present invention, all technical and scientific terms have the meanings that are commonly understood by those of ordinary skill in the art to which this invention belongs. The terms used in the description of the present invention are merely for the purpose of effectively describing specific embodiments and are not intended to limit the present invention.

[0059] Furthermore, when a part "comprises" a certain element, this does not mean that it excludes other elements, but that it may further include other elements, unless otherwise specified. Furthermore, the singular expression includes the plural expression unless the context clearly indicates otherwise.

[0060] In the following, unless otherwise specified, units used are based on weight, and as an example, units of % or ratio mean weight % or weight ratio.

[0061] Furthermore, when describing the components of the present invention, terms such as first, second, (A), (B), (a), (b), etc. are used only to distinguish the component from other components, and the terms do not limit the essence, order, or sequence of the components.

[0062] The present inventors have found that particle size is a very important factor in improving flame retardancy and in the applications and usage environments of flame retardants, and as a result of extensive research to resolve this issue, have discovered that a particle size-adjusted hypophosphite-based flame retardant can impart excellent flame retardancy to adhesive compositions that require a thin thickness or compositions that require heat resistance, and that a hypophosphite-based metal salt flame retardant having such advantages can be produced by a simple and economical method, leading to the completion of the present invention.

[0063] The hypophosphite-based flame retardant and its production method according to the present invention will be described in detail below.

[0064] The hypophosphite-based flame retardant according to the present invention satisfies the following formulas 1 and 2 and is represented by chemical formula 1.

[0065] [Formula 1]0.1 <D 50 / (D 98 -D 50 )<0.6

[0066] [Formula 2] 250℃ <T CG <320℃

[0067] [Chemical formula 1] JPEG2026504902000004.jpg3159

[0068] In the above formula 1, when measured by a laser diffraction scattering method, the particle size corresponding to 50% of the cumulative volume of the particle size distribution is D 50 The particle size corresponding to 98% of the cumulative volume of the particle size distribution is D 98 is.

[0069] In the above formula 2, TCG means the first temperature at which a weight loss of 1.0% occurs under thermogravimetric analysis conditions of a heating rate of 10° C. / min and a nitrogen flow rate of 20 ml / min.

[0070] In the above Chemical Formula 1, R1 and R2 are hydrogen or, independently of each other, linear or branched (C1-C6) alkyl; M is a metal atom of Ca, Mg, Al, Zn, or Ti; and n is an integer selected from 2 to 4.

[0071] Specifically, R1 and R2 may be each independently (C1-C3) alkyl, M may be an Al metal atom from the viewpoint of ease of particle size adjustment and heat resistance, and n may be 2 to 3.

[0072] The formula 1 means the particle size distribution width of the hypophosphite-based flame retardant, and the particle size distribution width (D 50 / (D 98 -D 50 Preferably, the particle size distribution width (D 50 / (D 98 -D 50 )) may be 0.19 or more and 0.58 or less. In this case, the D50 of the flame retardant may be 30 μm or less and the D98 may be 100 μm or less, specifically, the D50 may be 29 μm or less and the D98 may be 80 μm or less, and, without limitation, the D50 may be 1 μm or more and the D98 may be 12 μm or more. The larger the D50 of the flame retardant, the more improved the heat resistance of the flame retardant. However, if the D50 of the flame retardant is outside the above range, it may not be suitable for the intended use.

[0073] The formula 2 relates to the thermal stability of hypophosphite flame retardants, and T CG The temperature satisfies the condition of more than 250°C and less than 320°C, and may be preferably 255°C or higher and 315°C or lower.

[0074] By adjusting the particle size, the hypophosphite-based flame retardant satisfying the above formulas 1 and 2 can impart excellent flame retardancy to adhesive compositions that require a thin thickness or compositions that require heat resistance, without impairing the physical properties of the product.

[0075] In one embodiment, the hypophosphite flame retardant according to the present invention may satisfy formula 3 and formula 4.

[0076] [Formula 3]0.1 <D 50 / (D 98 -D 50 )<0.3

[0077] [Formula 4] 250℃ <T CG <280°C

[0078] In the formulas 3 and 4, D 50 , D 98 , and T CG has the same meaning as explained in Equations 1 and 2, so a detailed explanation will be omitted.

[0079] By satisfying the above formulas 3 and 4, the particle size can be adjusted to suit an adhesive composition that requires a thin thickness, which can be advantageous in improving the thermal stability of the adhesive composition. Furthermore, because the average particle size of the flame retardant is small and it has excellent thermal stability, even when the flame retardant is contained in a product that requires a thin thickness, such as an adhesive for CCL (Copper Clad Laminate) or FFC (Flexible Flat Cable), it is possible to impart the required flame retardancy to the adhesive without impairing the physical properties of the adhesive.

[0080] Hypophosphite flame retardants that satisfy formulas 3 and 4 are D 50 is 6 μm or less and D 98 is 35 μm or less, or D 50 is 5.5 μm or less and D 98 may be 33 μm or less, and may be, but is not limited to, D 50 is 1 μm or more and D 98 is 12 μm or more, or D 50 is 2.5 μm or more and D 98 Specifically, D 50 may be 1 to 6 μm or 2.5 to 5.5 μm, and D 98 may be 12 to 35 μm, or 15 to 33 μm.

[0081] In one embodiment, the hypophosphite flame retardant of the present invention represented by Chemical Formula 1 may satisfy Formula 5 and Formula 6.

[0082] [Formula 5]0.35 <D 50 / (D 98 -D 50 )<0.6

[0083] [Formula 6]290℃ <T CG <320℃

[0084] Hypophosphite flame retardants satisfying the above formulas 5 and 6 can be adjusted to a large particle size, have excellent flowability during processing, and are easy to process. They are also easily crushed and exhibit excellent dispersibility when blended into resins. Surprisingly, satisfying formula 5 significantly improves heat resistance, enabling high-temperature processing of resins and preventing bridging in hoppers. Thus, hypophosphite flame retardants satisfying formulas 5 and 6 can be blended with resins having high decomposition temperatures to improve the heat resistance of the resins. The resins having high decomposition temperatures may be polyesters or polyamides, and specific examples include, but are not limited to, polybutylene terephthalate, polyethylene terephthalate, polyphthalamide, and nylon 6,6.

[0085] Hypophosphite flame retardants that satisfy formulas 5 and 6 are D 50 is 10 μm or more and D 98 is 40 μm or more, or D 50 is 13 μm or more and D 98 is 48 μm or more, and, non-limitingly, D 50 is 32 μm or less and D 98 is 100 μm or less, or D 50 is 30 μm or less and D 98 Specifically, D 50 may be 10 to 32 μm, 13 to 30 μm, or 23 to 30 μm, and D 98 The thickness may be 40 to 100 μm, 48 to 80 μm, or 70 to 80 μm.

[0086] A method for producing a hypophosphite flame retardant according to one aspect of the present invention includes the steps of: a) stirring an alkali metal hypophosphite, a (C2-C4) alkene, a radical initiator, and water to produce an alkyl metal hypophosphite; b) reacting the alkyl metal hypophosphite produced in step a) with a divalent to tetravalent metal salt to produce a hypophosphite metal salt; c) washing the hypophosphite metal salt produced in step b) with distilled water; and d) drying the washed hypophosphite metal salt in a vacuum to produce a hypophosphite flame retardant represented by the following chemical formula 1, wherein in step b), at least one of the alkyl metal hypophosphite and the divalent to tetravalent metal salt is supplied through a nozzle.

[0087] [Chemical formula 1] JPEG2026504902000005.jpg3159

[0088] In the above Chemical Formula 1, R1 and R2 are hydrogen or, independently of each other, linear or branched (C1-C6) alkyl; M is a metal atom of Ca, Mg, Al, Zn, or Ti; and n is an integer selected from 2 to 4.

[0089] When hypophosphite flame retardants are manufactured using hypophosphorous acid and metal hydroxide, aluminum hydroxide, which is commonly used in manufacturing flame retardants, is hardly soluble in water, so it is difficult to find a way to adjust the particle size other than pulverization. Furthermore, it is basically impossible to manufacture flame retardants with large particle sizes.

[0090] Another common method for producing hypophosphite-based flame retardants is to prepare an alkali metal hypophosphite salt using hypophosphorous acid and an alkali metal hydroxide, followed by reaction with a divalent to tetravalent metal salt. When hypophosphorous acid is used as a raw material, a step of reacting the intermediate alkyl hypophosphite with a metal hydroxide is unavoidable. If the metal hydroxide salt used in this step is not used in the correct proportions, the yield will decrease, and insoluble divalent to tetravalent metal hydroxide salts will be produced and remain as impurities. This not only hinders filtration, but also increases the amount of reaction by-products remaining in the final flame retardant. Remaining reaction by-products in the flame retardant can reduce the flame retardancy and heat resistance of the flame retardant.

[0091] However, in the present invention, since step a) does not use hypophosphorous acid as a raw material but uses an alkali metal hypophosphite as a raw material, the step of reacting with a metal hydroxide can be omitted, thereby reducing the amount of energy and water used in the manufacturing process. Furthermore, since the manufacturing method of the present invention does not include the step of reacting with a metal hydroxide, when a composition containing a hypophosphite-based flame retardant and a resin, or a hypophosphite-based flame retardant and an adhesive polymer is molded and processed, water is not generated due to the metal hydroxide, which has a low dehydration temperature, and product defects can be prevented in advance. Furthermore, since the manufacturing method of the present invention uses an alkali metal hypophosphite as a raw material, it has the advantage of easily adjusting the particle size of the flame retardant. The alkali metal hypophosphite may be sodium hypophosphite or potassium hypophosphite. The concentration of the alkali metal hypophosphite may be 5 to 70 wt %, more preferably 10 to 60 wt %, even more preferably 20 to 50 wt %, and most preferably 30 to 40 wt % of the total amount of the alkali metal hypophosphite, (C2-C4) alkene, radical initiator, and water used in step a), and when it is in such a range, excellent reaction efficiency can be exhibited.

[0092] The (C2-C4) alkene may be any one or more selected from alkenes having 2 to 4 carbon atoms, specifically ethylene, propene, 1-butene, or 2-butene, and is preferably ethylene in terms of improving flame retardancy.

[0093] The radical initiator is not limited, but specifically includes any one or a mixture of two or more selected from the group consisting of 2,2-azobis(2-amidinopropene) dihydrochloride, sodium persulfate, potassium persulfate, and ammonium persulfate. The content of the radical initiator is preferably 0.5 to 15 mol %, more preferably 1 to 10 mol %, based on the alkali metal hypophosphite, which is advantageous in terms of reaction rate and economy.

[0094] The water may be distilled or deionized water.

[0095] The reaction temperature in step a) may be maintained at 50 to 150° C., and the reaction pressure may be maintained at 5 to 10 atm.

[0096] The step b) is a step of substituting the metal of the alkyl hypophosphite metal salt with a divalent to tetravalent metal. For example, the following substitution reaction can occur:

[0097] JPEG2026504902000006.jpg22154

[0098] The step b) can improve the heat resistance and water resistance of the flame retardant.

[0099] The divalent to tetravalent metal salt may be a nitrate, hydrochloride, or sulfate of a divalent to tetravalent metal, and the divalent to tetravalent metal may be calcium (Ca), magnesium (Mg), aluminum (Al), zinc (Zn), titanium (Ti), etc. Considering the improvement of the heat resistance and water resistance of the flame retardant, the absence of halogen elements, and the low cost, it is advantageous to use an aluminum sulfate as the divalent to tetravalent metal salt.

[0100] The amount of the divalent to tetravalent metal salt added is preferably 3 times or more by mole, more preferably 4 to 8 times by mole, and even more preferably 5 to 7 times by mole, based on 1 mole of the alkyl metal hypophosphite. When the above range is satisfied, there is an advantage that no unreacted material that is not substituted with the divalent to tetravalent metal salt remains.

[0101] The reaction temperature in step b) may be room temperature, specifically 20 to 50° C., and preferably 25 to 45° C. When the reaction is carried out within the above temperature range, the particle size of the final flame retardant may not change significantly.

[0102] In step b), at least one of alkyl hypophosphite metal salt and divalent to tetravalent metal salt is supplied to the reactor through a nozzle, which may be a straight nozzle, a full cone nozzle, or a spray nozzle. The number of nozzles inserted into the reactor and through which the reactants are supplied may be 1 to 50, specifically 2 to 30, but is not limited thereto.

[0103] The method for producing the hypophosphite-based flame retardant may be carried out by a batch or continuous reaction.

[0104] According to one embodiment, in the batch reaction, when at least one raw material of alkyl hypophosphite metal salt and divalent to tetravalent metal salt is sprayed through a nozzle in step b), one of the two raw materials charged in the reactor can be sprayed onto the other raw material to produce a hypophosphite-based flame retardant.

[0105] According to one embodiment, in the continuous reaction, at least one raw material selected from alkyl hypophosphite metal salt and divalent to tetravalent metal salt in step b) is continuously injected into a reactor through a nozzle, and simultaneously an alkyl hypophosphite metal salt solution is continuously injected through a nozzle, whereby a hypophosphite-based flame retardant is produced in the reactor through a reaction between the injected droplets, and the product can be continuously discharged outside the reactor.

[0106] According to one embodiment, a flame retardant produced by supplying at least one raw material selected from alkyl metal hypophosphite and divalent to tetravalent metal salt through a straight nozzle may satisfy the following formulas 3 and 4.

[0107] [Formula 3]0.1 <D 50 / (D 98 -D 50 )<0.3

[0108] [Formula 4] 250℃ <T CG <280°C

[0109] When at least one of alkyl hypophosphite metal salt and divalent to tetravalent metal salt is supplied through the straight nozzle, the nozzle conduit is preferably formed vertically downward from the upper end. If the nozzle is sprayed on the wall of the reactor, the concentration of the two raw materials at the moment of contact will change, which is disadvantageous in obtaining a product with a uniform particle size.

[0110] The divalent to tetravalent metal salt may be supplied as a solution dissolved in water, and the concentration of the divalent to tetravalent metal salt may be 10 to 30% by weight, more preferably 15 to 25% by weight.

[0111] Furthermore, when at least one of alkyl hypophosphite metal salt and divalent to tetravalent metal salt is supplied through a straight nozzle, the surface area of ​​the supplied raw material that comes into contact with the liquid surface containing the raw materials in the reactor is not large, making it easy to adjust the particle size of the final flame retardant so that it satisfies Equation 3.

[0112] According to one embodiment, the raw material is supplied through a full cone nozzle or a spray nozzle, whereby a hypophosphite-based flame retardant satisfying the following formulas 5 and 6 can be produced.

[0113] [Formula 5]0.35 <D 50 / (D 98 -D 50 )<0.6

[0114] [Formula 6]290℃ <T CG <320℃

[0115] When the raw materials are fed into the reactor through the full cone nozzle or spray nozzle, fine droplets are introduced, so that the concentration at the moment of contact is extremely low and a flame retardant with large particle size is produced.

[0116] The divalent to tetravalent metal salt may be supplied as a solution dissolved in water, as in the case of supplying the salt through a straight nozzle, and in this case, the concentration can be applied in the same manner as in the case of supplying the salt through a straight nozzle.

[0117] In addition, step b) may be carried out by adding water. If water is further added in step b), which is a reaction step, the filtration time can be reduced, the yield of the final product can be increased, and the final T of the hypophosphite flame retardant can be improved. CG This has the advantage of improving the heat resistance of the flame retardant.

[0118] The amount of water added in step b) may be 0.5 to 5.0 times, more preferably 0.9 to 3.5 times, the weight of the resulting flame retardant, but it is advantageous not to exceed 4.0 times in terms of the amount of water used and wastewater generation.

[0119] In step c), the alkyl hypophosphite metal salt produced in step b) is washed with water to remove impurities such as the initiator, the reaction by-product sodium sulfate (Na2SO4), and unreacted raw materials, thereby improving purity. The washing method is not particularly limited, but high purity can be achieved by washing with distilled water at room temperature 2 to 4 times.

[0120] The method for producing a hypophosphite-based flame retardant of the present invention includes the step of: d) drying the hypophosphite-based metal salt washed with water in step c) under vacuum conditions to produce a hypophosphite-based flame retardant represented by the following Chemical Formula 1:

[0121] The step of drying under vacuum conditions is a step for removing water used as a solvent in the reaction and washing processes. The vacuum drying method is not particularly limited, but drying at a temperature of 100 to 150°C and under vacuum conditions of 1.0 mmHg or less is preferred because it can completely remove the moisture in the hypophosphite-based flame retardant to 1 wt% or less.

[0122] Another aspect of the present invention relates to an adhesive composition comprising the above-mentioned hypophosphite-based flame retardant and an adhesive polymer, wherein the hypophosphite-based flame retardant satisfies the following formula 3:

[0123] [Formula 3]0.1 <D 50 / (D 98 -D 50 )<0.3

[0124] Examples of the adhesive polymer include, but are not limited to, polyethylene terephthalate, vinyl acetate polymers, vinyl chloride polymers, epoxy polymers, urethane polymers, polyimide polymers, and acrylate polymers.

[0125] The hypophosphite-based flame retardant may be contained in an amount of 1 to 30 parts by weight, specifically 2 to 20 parts by weight, relative to 100 parts by weight of the adhesive polymer, but is not limited thereto.

[0126] The particle size of the hypophosphite-based flame retardant satisfying the above formula 3 is adjusted to be suitable for adhesive compositions requiring a thin thickness, i.e., compositions for CCL (Copper Clad Laminate) or FFC (Flexible Flat Cable), where the coating layer thickness is limited to 40 μm or less. Even when included in the adhesive composition, the hypophosphite-based flame retardant is advantageous in improving the thermal stability of the adhesive composition without deteriorating the physical properties of the adhesive composition.

[0127] Specifically, the numerical range according to formula 3 may be 0.15 to 0.3, and preferably 0.2 to 0.29.

[0128] The present invention can provide a flame-retardant composition comprising the above-mentioned hypophosphite-based flame retardant and a resin, wherein the hypophosphite-based flame retardant satisfies the following formulas 5 and 6.

[0129] [Formula 5]0.35 <D 50 / (D 98 -D 50 )<0.6

[0130] [Formula 6]290℃ <T CG <320℃

[0131] The hypophosphite flame retardants satisfying the above formulas 5 and 6 are adjusted to have larger particle sizes and higher heat resistance than hypophosphite flame retardants satisfying the above formula 3, and therefore can be used in combination with resins that require high-temperature processing and have high decomposition temperatures.

[0132] Specifically, the numerical range of formula 6 may be 0.38 to 0.6, preferably 0.45 to 0.6, and more preferably 0.47 to 0.58.

[0133] Specific examples of the resin having a high decomposition temperature include, but are not limited to, polybutylene terephthalate, polyethylene terephthalate, polyphthalamide, and nylon 6,6.

[0134] The present invention will be described in detail below with reference to the following Production Examples and Examples, but the following Production Examples and Examples are merely illustrative of the present invention and are not intended to limit the scope of the invention.

[0135] [Manufacturing Example] Synthesis of sodium diethyl hypophosphinate (SDP) JPEG2026504902000007.jpg2113350 wt% sodium hypophosphite (1,200 kg, 5660.4 mol) was added to a 3,000 L high-pressure reactor equipped with a stirrer, and ethylene was added at 6 kg / cm 2The vessel was filled to a pressure of 1000 kJ / s, then emptied, and further filled with ethylene until the same pressure was reached, removing the air from the gas phase. To maintain this pressure while the reaction was proceeding, the valve was opened while connected to an ethylene storage tank. 100 kg of ammonium persulfate (initiator) was dissolved in 400 kg of water in a separately prepared 1,000 L vessel, and the solution was continuously injected at a rate of approximately 20 L / h using a high-pressure plunger pump.

[0136] After 18 hours of reaction at 70°C, no further ethylene was consumed, and the ethylene substitution reaction was assumed to be complete. A 200 kg sample was taken, cooled to room temperature, and then the water was removed using a rotary evaporator. The precipitate was filtered and the resulting sample was analyzed using 600 MHz H-NMR. The pure SDP content in the reaction solution was 42.7 wt%.

[0137] Figure 1 shows the H-NMR measurement results for the SDP produced in the production example. The peaks around 6-8 ppm corresponding to the PH bond are barely visible, confirming that the reaction proceeded completely.

[0138] [Example 1] 1,892 kg (5.61 kmol) of the SDP solution prepared in the Preparation Example was charged into a 5-ton reactor, and the temperature of the reactor was adjusted to 25°C. 1,497 kg (1.03 kmol) of a 23.5 wt% aqueous aluminum sulfate solution was then pumped through straight nozzles (Daewoo Nozzle, 1 / 8MCP31, 25 pieces) attached to the end of a 40 mm pipe connected to a pump at a pressure of 3 kg / cm. 2 The solution was fed from the top of the reactor at a flow rate of 30 L / min for 50 minutes. After maintaining the temperature at 25°C for 60 minutes, it was transferred to a filter and filtered for 4 hours. The product was washed four times with 1,000 kg of room temperature distilled water and then vacuum dried at 114°C / 1.0 mmHg to obtain 715.1 kg of aluminum diethylphosphinate (ADP) (yield: 97.9%). The obtained ADP was subjected to thermogravimetric analysis and particle size distribution measurement, and the results are summarized in Table 1.

[0139] [Example 2] A 5-ton reactor was charged with 1,892 kg (5.61 kmol) of the SDP solution prepared in Preparation Example 1. The reactor temperature was then adjusted to 25°C. 1,497 kg (1.03 kmol) of a 23.5 wt. % aluminum sulfate aqueous solution was then added to the top of the reactor over 50 minutes via full-cone nozzles (Daewoo Nozzle, 1 / 8R2.8W (11 / 8RR2.8W), six nozzles, 120° spray angle per nozzle) attached to the end of a 40 mm pipe connected to a pump. After maintaining the temperature at 25°C for 60 minutes, the mixture was transferred to a filter and filtered for 4 hours. Water washing and drying were performed as in Example 1, yielding 715.1 kg of aluminum diethylphosphinate (ADP) (98.1% yield). The resulting ADP was subjected to thermogravimetric analysis and particle size distribution analysis, and the results are summarized in Table 1.

[0140] [Example 3] Into a 200 L reactor filled with 100 kg of distilled water, 1,892 kg (5.61 kmol) of the SDP solution prepared in the above Preparation Example and 1,497 kg (1.03 kmol) of a 23.5 wt % aqueous aluminum sulfate solution were added at a pressure of 3 kg / cm through seventeen 1.6 mm straight downward nozzles attached to the ends of 40 mm injection pipes connected to a pump. 2 , and 200 ml of water were simultaneously fed from the top of the reactor at a flow rate of 30 L / min for 50 minutes. The reaction liquid was continuously transferred to a filter via a transfer pipe connected to the top of the reactor. The transferred reaction liquid was transferred to the filter and filtered for 5 hours. Water washing and drying steps were carried out in the same manner as in Example 1, and 714.4 kg of aluminum diethylphosphinate (ADP) was obtained (yield 98.0%). The obtained ADP was subjected to thermogravimetric analysis and particle size distribution measurement, and the results are summarized in Table 1.

[0141] [Example 4] Into a 200 L reactor filled with 150 kg of distilled water, 1,892 kg (5.61 kmol) of the SDP solution prepared in the above Preparation Example and 1,497 kg (1.03 kmol) of a 23.5 wt % aqueous aluminum sulfate solution were injected at a pressure of 3 kg / cm through three sets of 25 1.5 mm spray nozzles (Daewoo Nozzle, 1 / 4" Fog-Jet, spray angle 60-70° per nozzle) attached to the end of a 40 mm injection pipe connected to a pump. 2 The resulting solution was fed from the top of the reactor at a flow rate of 22.5 L / min for 60 minutes. After maintaining the temperature at 25°C for 60 minutes, the solution was transferred to a filter and filtered for 1 hour. The water washing and drying steps were carried out in the same manner as in Example 1, yielding 719.8 kg of aluminum diethylphosphinate (ADP) (yield 98.5%). The obtained ADP was subjected to thermogravimetric analysis and particle size distribution measurement, and the results are summarized in Table 1.

[0142] [Example 5] The same procedure as in Example 1 was carried out, except that 1,892 kg (5.61 kmol) of the SDP solution prepared in Preparation Example was added, the temperature of the reactor was adjusted to 45°C, and the mixture was transferred to a filter and filtered for 15 hours. Aluminum diethylphosphinate (ADP) was obtained in a yield of 97.5%. The obtained ADP was subjected to thermogravimetric analysis and particle size distribution measurement, and the results are summarized in Table 1.

[0143] [Example 6] Into a 200 L reactor filled with 100 kg of distilled water, 1,892 kg (5.61 kmol) of the SDP solution prepared in the above Preparation Example and 1,497 kg (1.03 kmol) of a 23.5 wt % aqueous aluminum sulfate solution were added at a pressure of 3 kg / cm through seventeen 1.6 mm straight downward nozzles attached to the ends of 40 mm injection pipes connected to a pump. 2The reaction mixture was fed from the top of the reactor at a flow rate of 22.5 L / min for 50 minutes. The procedure was the same as in Example 3, except that the temperature was maintained at 45°C for 60 minutes, to obtain aluminum diethylphosphinate (ADP). The yield was 98.0%. The obtained ADP was subjected to thermogravimetric analysis and particle size distribution measurement, and the results are summarized in Table 1.

[0144] [Example 7] Into a 200 L reactor filled with 150 kg of distilled water, 1,892 kg (5.61 kmol) of the SDP solution prepared in the above Preparation Example and 1,497 kg (1.03 kmol) of a 23.5 wt % aqueous aluminum sulfate solution were injected at a pressure of 3 kg / cm through three sets of 25 1.5 mm spray nozzles (Daewoo Nozzle, 1 / 4" Fog-Jet, spray angle 60-70° per nozzle) attached to the end of a 40 mm injection pipe connected to a pump. 2 The reaction mixture was fed from the top of the reactor at a flow rate of 38 L / min for 50 minutes. The procedure was the same as in Example 4, except that the reactor was maintained at 45°C, to obtain aluminum diethylphosphinate (ADP). The yield was 98.5%. The obtained ADP was subjected to thermogravimetric analysis and particle size distribution measurement, and the results are summarized in Table 1.

[0145] [Example 8] 1,892 kg (5.61 kmol) of the SDP solution prepared in Preparation Example was mixed with 730 kg of distilled water to adjust the concentration of the reaction solution, and the solution was then charged into a reactor. The temperature of the reactor was adjusted to 25°C, and 1,497 kg (1.03 kmol) of a 23.5 wt% aqueous aluminum sulfate solution was pumped through straight nozzles (Dew Nozzle, 1 / 8MCP31, 25 pieces) attached to the tip of a 40 mm pipe connected to a pump at a pressure of 3 kg / cm. 2The same procedure as in Example 1 was carried out, except that the sintered body was fed from the top of the reactor at a flow rate of 38 L / min for 50 minutes, to obtain aluminum diethylphosphinate (ADP). The yield was 98.0%. The obtained ADP was subjected to thermogravimetric analysis and particle size distribution measurement, and the results are summarized in Table 1.

[0146] [Example 9] The same procedure as in Example 1 was carried out, except that 1,892 kg (5.61 kmol) of SDP solution was mixed with 2,190 kg of distilled water to adjust the concentration of the reaction solution, and filtration was carried out for 3 hours. Aluminum diethylphosphinate (ADP) was obtained in a yield of 98.3%. The obtained ADP was subjected to thermogravimetric analysis and particle size distribution measurement, and the results are summarized in Table 1.

[0147] [Example 10] The same procedure as in Example 2 was carried out, except that 1,892 kg (5.61 kmol) of SDP solution was mixed with 2,342 kg of distilled water to adjust the concentration of the reaction solution, and filtration was carried out for 2 hours. Aluminum diethylphosphinate (ADP) was obtained in a yield of 98.7%. The obtained ADP was subjected to thermogravimetric analysis and particle size distribution measurement, and the results are summarized in Table 1.

[0148] [Table 1]

[0149] As can be seen from Table 1, D 50 / (D 98 -D 50 ) value, T CG (℃) increases, and the heat resistance improves. In addition, when the reaction temperature and the type of nozzle used are the same, the T CG It can be seen that the temperature (°C) is higher than that produced by batch reaction.

[0150] When divalent to tetravalent metal salts are supplied through a straight nozzle (Examples 1, 3, 5, 6, 8, and 9) during batch or continuous reactions, D 50 / (D 98 -D 50 ) is greater than 0.1 and less than 0.3, and D 50 is 6 μm or less and D 98 Small size particles were produced, with a particle size of 35 μm or less.

[0151] During batch or continuous reactions, when divalent to tetravalent metal salts are supplied through a full cone nozzle (Examples 2 and 10) or a spray nozzle (Examples 4 and 7), D 50 / (D 98 -D 50 ) is greater than 0.35 and less than 0.6, and D 50 is 13 μm or more and less than 30 μm, D 98 The particle size was 40 μm or more and 80 μm or less, and large size particles were produced.

[0152] During the batch reaction (comparison of Example 1 with Examples 8 and 9) or the continuous reaction (comparison of Example 2 with Example 10), when no additional water was added to the reactor (Examples 1 and 2), and when additional water was added (Examples 8, 9 and 10), D 50 / (D 98 -D 50 ) in the same category as T CG (℃) value increased, the filtration time decreased, and the reaction yield increased. 50 / (D 98 -D 50 ) increases with T CG The (°C) value increases, indicating that adding water in the reaction step increases productivity and heat resistance.

[0153] When a spray nozzle is used during continuous reaction (Examples 4 and 7), D is 50 / (D 98 -D 50 ) value, reaction yield (%), and T CGThe (°C) value is larger, and the use of a spray nozzle in a continuous reaction is effective in terms of productivity and heat resistance of the hypophosphite flame retardant.

Claims

1. A hypophosphite-based flame retardant that satisfies the following formulas 1 and 2 and is represented by the following chemical formula 1: [Formula 1] 0.1<D ５０ / (D ９８ -D ５０ )<0.6 [Formula 2] 250℃<T ＣＧ <320℃ [Chemical formula 1] (In the above formula 1, when measured by a laser diffraction scattering method, the particle size corresponding to 50% of the cumulative volume of the particle size distribution is D ５０ The particle size corresponding to 98% of the cumulative volume of the particle size distribution is D ９８ is. In the formula 2, T ＣＧ means the first temperature at which a weight loss of 1.0% occurs under thermogravimetric analysis conditions of a heating rate of 10° C. / min and a nitrogen flow rate of 20 ml / min. In the above formula 1, R １ and R ２ are hydrogen or each independently a linear or branched (C １ -C ６ ) alkyl, M is a metal atom of Ca, Mg, Al, Zn, or Ti, and n is an integer selected from 2 to 4.

2. The hypophosphite-based flame retardant according to claim 1, which satisfies the following formula 3: [Formula 3] 0.1<D ５０ / (D ９８ -D ５０ )<0.3 (In the above formula 3, when measured by a laser diffraction scattering method, the particle size corresponding to 50% of the cumulative volume of the particle size distribution is D ５０ The particle size corresponding to 98% of the cumulative volume of the particle size distribution is D ９８ It is.)

3. The hypophosphite-based flame retardant according to claim 1, which satisfies the following formulas 5 and 6: [Formula 5] 0.35<D ５０ / (D ９８ -D ５０ )<0.6 [Formula 6] 290℃<T ＣＧ <320℃ (In the above formula 5, when measured by a laser diffraction scattering method, the particle size corresponding to 50% of the volume cumulative of the particle size distribution is D ５０ The particle size corresponding to 98% of the cumulative volume of the particle size distribution is D ９８ is. In the above formula 6, T ＣＧ means the first temperature at which a weight loss of 1.0% occurs under thermogravimetric analysis conditions of a heating rate of 10°C / min and a nitrogen flow rate of 20 ml / min.

4. D of the flame retardant ５０ The hypophosphite flame retardant according to claim 1, wherein the particle size is 30 μm or less.

5. D of the flame retardant ９８ The hypophosphite flame retardant according to claim 1, wherein the particle size is 100 μm or less.

6. a) stirring an alkali metal hypophosphite, a (C2-C4) alkene, a radical initiator, and water to produce an alkyl metal hypophosphite; b) reacting the alkyl hypophosphite metal salt prepared in step a) with a divalent to tetravalent metal salt to prepare a hypophosphite metal salt; c) washing the hypophosphite metal salt prepared in step b) with distilled water; d) drying the hypophosphite metal salt washed in step c) under vacuum conditions to prepare a hypophosphite flame retardant represented by the following Chemical Formula 1: In the step b), at least one raw material selected from the group consisting of the alkyl hypophosphite metal salt and the divalent to tetravalent metal salt is supplied through a nozzle. [Chemical formula 1] (In the above chemical formula 1, R １ and R ２ are hydrogen or each independently a linear or branched (C １ -C ６ ) alkyl, M is a metal atom of Ca, Mg, Al, Zn, or Ti, and n is an integer selected from 2 to 4.

7. The method for producing a hypophosphite-based flame retardant according to claim 6, wherein the nozzle is a straight nozzle, a full cone nozzle, or a spray nozzle.

8. The method for producing a hypophosphite-based flame retardant according to claim 7, wherein the raw material is supplied through the straight nozzle, and the flame retardant satisfies the following formula 3: [Formula 3] 0.1<D ５０ / (D ９８ -D ５０ )<0.3 (In the above formula 3, when measured by a laser diffraction scattering method, the particle size corresponding to 50% of the cumulative volume of the particle size distribution is D ５０ The particle size corresponding to 98% of the cumulative volume of the particle size distribution is D ９８ It is.)

9. The method for producing a hypophosphite-based flame retardant according to claim 7, wherein the raw material is supplied through the full cone nozzle or the spray nozzle, and the flame retardant satisfies the following formulas 5 and 6: [Formula 5] 0.35<D ５０ / (D ９８ -D ５０ )<0.6 [Formula 6] 290℃<T ＣＧ <320℃ (In the above formula 5, when measured by a laser diffraction scattering method, the particle size corresponding to 50% of the volume cumulative of the particle size distribution is D ５０ The particle size corresponding to 98% of the cumulative volume of the particle size distribution is D ９８ is. In the above formula 6, T ＣＧ means the first temperature at which a weight loss of 1.0% occurs under thermogravimetric analysis conditions of a heating rate of 10°C / min and a nitrogen flow rate of 20 ml / min.

10. 7. The method for producing a hypophosphite flame retardant according to claim 6, wherein the divalent to tetravalent metal salt is a hydrochloride, sulfate, or nitrate of a divalent to tetravalent metal.

11. The method for producing a hypophosphite-based flame retardant according to claim 6, wherein the reaction temperature in step b) is 60°C or less.

12. An adhesive composition comprising the hypophosphite flame retardant according to any one of claims 1 to 5 and an adhesive polymer, wherein the hypophosphite flame retardant satisfies the following formula 3: [Formula 3] 0.1<D ５０ / (D ９８ -D ５０ )<0.3 (In the above formula 3, when measured by a laser diffraction scattering method, the particle size corresponding to 50% of the cumulative volume of the particle size distribution is D ５０ The particle size corresponding to 98% of the cumulative volume of the particle size distribution is D ９８ It is.)

13. The adhesive composition according to claim 12, which is for use in CCL (Copper Clad Laminate) or FFC (Flexible Flat Cable).

14. A flame-retardant composition comprising the hypophosphite-based flame retardant according to any one of claims 1 to 5 and a resin, wherein the flame retardant satisfies the following formulas 5 and 6: [Formula 5] 0.35<D ５０ / (D ９８ -D ５０ )<0.6 [Formula 6] 290℃<T ＣＧ <320℃ (In the above formula 5, when measured by a laser diffraction scattering method, the particle size corresponding to 50% of the volume cumulative of the particle size distribution is D ５０ The particle size corresponding to 98% of the cumulative volume of the particle size distribution is D ９８ is. In the above formula 6, T ＣＧ means the first temperature at which a weight loss of 1.0% occurs under thermogravimetric analysis conditions of a heating rate of 10°C / min and a nitrogen flow rate of 20 ml / min.

15. 15. The flame retardant composition of claim 14, wherein the resin is polybutylene terephthalate, polyethylene terephthalate, polybutalamide, or nylon 6,6.

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