KR102095283B1 - Manufacturing Method of Hypophosphorous Type Flame Retardants - Google Patents

Abstract

The present invention relates to a method for producing a hypophosphite-based flame retardant. More specifically, it relates to a method for manufacturing a hypophosphite-based flame retardant that can finely control particle size and solve discoloration and heat resistance problems, including reacting a hypophosphite salt and an aluminum salt under conditions where ultrasonic energy is applied.

Description

Manufacturing Method of Hypophosphorous Type Flame Retardants

The present invention relates to a method for producing a hypophosphite-based flame retardant. More specifically, it relates to a method for manufacturing a hypophosphite-based flame retardant that can finely control particle size and solve discoloration and heat resistance problems, including reacting a hypophosphite salt and an aluminum salt under conditions where ultrasonic energy is applied.

In general, since the thermoplastic polymer material is easily burned and has a fire risk, there has been a demand for a flame retardant technology. Conventional flame retardant has used a halogen-based compound containing bromine or chlorine having flame retardancy and heat resistance. However, these halogen-based flame retardants have a problem that is harmful to the human body and the environment by generating toxic substances such as toxic gases and dioxin during combustion. Accordingly, restrictions on use of halogen flame retardants are being strengthened, and development of non-halogen flame retardants having excellent flame retardancy and heat resistance to replace halogen flame retardants is urgently required.

Among the alternatives of halogen-based flame retardants, phosphorus-based compounds have superior flame retardancy compared to inorganic-based flame retardants or nitrogen-based flame retardants, but do not have a significant flame retardant and heat-resistant performance compared to halogen-based compounds. In addition, the heat resistance, corrosion resistance and discoloration resistance are not good, the smoke density is high in the combustion process, and the productivity is low due to the filtration washing process for by-product treatment in the manufacturing process.

In addition, inorganic flame retardants such as aluminum hydroxide and magnesium hydroxide are difficult to simultaneously improve flame retardancy and mechanical properties, and nitrogen-based flame retardants such as melamine cyanurate are used in most applications except nitrogen-containing resins such as polyamide or polyurethane. It is mainly used as a flame retardant supplement due to its lack of flame retardancy.

On the other hand, since adhesives used in FFC (Flexible Flat Cable), which is one field of electronic materials, generally have a thickness within 30 µm, it is difficult to use flame retardants with large particle sizes, so it is also necessary to finely control the particle size of flame retardants. .

The present invention has been devised to solve the above problems, and provides a hypophosphite-based flame retardant and a method for manufacturing the same, which has excellent heat resistance, discoloration resistance and corrosion resistance, and excellent flame retardancy while finely adjusting the particle size. The purpose.

In order to achieve the above object, an aspect of the present invention,

(a) a hypophosphite-based metal salt reaction step of reacting an alkali metal hypophosphite with a 2-4 tetravalent metal salt, (b) a washing step of washing the hypophosphite-based metal salt prepared in step (a) and (c) the (b) ) A drying step of vacuum drying the hypophosphite-based metal salt washed in step, wherein at least one of the steps (a) and (b) is carried out by applying ultrasonic energy. It is to provide a method for producing a hypophosphite-based flame retardant represented by.

[Formula 1]

(In the above formula 1, R ₁ and R ₂ are independently of each other hydrogen, straight chain or pulverized (C ₁ -C ₆ ) alkyl, M is any metal atom selected from Ca, Mg, Al, Zn and Ti , N represents an integer selected from 2 to 4.)

In the method for producing a hypophosphite-based flame retardant according to an embodiment of the present invention, the divalent or tetravalent metal salt is any one selected from the group consisting of nitrate, hydrochloride, sulfate and mixtures of divalent or tetravalent metals You can.

In the method for producing a hypophosphite-based flame retardant according to an embodiment of the present invention, the application of the ultrasonic energy may be performed within a wavelength range of 500 to 20,000 W and 10 to 100 KHz per 1,000 L of the reaction solution. .

In the method for manufacturing a hypophosphite-based flame retardant according to an embodiment of the present invention, the application time of the ultrasonic energy may be 30 minutes to 360 minutes.

In the method for producing a hypophosphite-based flame retardant according to an embodiment of the present invention, the alkali metal hypophosphite in step (a) is prepared by adding a metal hydroxide to (C ₂ -C ₄ ) alkyl hypophosphorous acid and stirring it. You can.

In the method for producing a hypophosphite-based flame retardant according to an embodiment of the present invention, the metal hydroxide may be any one or more selected from the group consisting of aluminum hydroxide, calcium hydroxide and magnesium hydroxide.

In the method for producing a hypophosphite-based flame retardant according to an embodiment of the present invention, the (C ₂ -C ₄ ) alkyl hypophosphite is prepared by stirring hypophosphorous acid, (C ₂ -C ₄ ) alkene, radical initiator and water It can be.

Further, another aspect of the present invention relates to a flame retardant produced by the above-described manufacturing method.

Flame retardant according to an embodiment of the present invention may satisfy the following relational expression 1.

[Relationship 1]

300 ℃ ≤ T _CG ≤ 400 ℃

(In the above relational expression 1, T _CG is the first temperature at which a weight loss of 1.0% appears under a thermogravimetric analysis condition of a heating rate of 10 ° C / min and a nitrogen flow rate of 20 mL / min.)

Another aspect of the present invention relates to a molded article manufactured by including the flame retardant. The molded body may be a flexible flat cable or a flexible copper clad laminate.

The present invention can lower the content of impurities by applying ultrasonic energy during the reaction and water washing process, and has the advantage of finely controlling the particle size. In addition, it has the advantage of being capable of producing a hypophosphite-based flame retardant capable of realizing excellent flame retardant performance while having excellent heat resistance, discoloration resistance and corrosion resistance. Moreover, it can realize excellent performance in the use of adhesives for manufacturing FFC and FCCL, and has the advantage of providing a non-halogen-based eco-friendly flame retardant.

1 shows the results of H-NMR analysis of diethylhypophosphorous acid (DEPA) according to Preparation Example 1.
Figure 2 shows a photograph measured to determine whether the flame retardant particles according to Comparative Example 3 (a), Example 12 (b) and Example 13 (c) yellowing and aggregation occurred.

Hereinafter, a method for manufacturing the hypophosphite-based flame retardant of the present invention and a flame retardant prepared therefrom will be described in detail. The present invention can be better understood by the following examples. The following examples are for illustrative purposes of the present invention and are not intended to limit the scope of protection defined by the appended claims. At this time, the technical terms and scientific terms used have a meaning that is understood by a person having ordinary knowledge in the technical field to which this invention belongs, unless otherwise defined.

The inventors of the present invention have problems of high smoke density in the case of phosphorus-based flame retardants to improve flame retardancy, and poor physical properties such as heat resistance and discoloration resistance, while deepening research to improve them, applying ultrasonic energy Impurity content can be lowered by providing a hypophosphite-based flame retardant manufacturing method comprising performing a reaction or water washing process under conditions, and in addition to excellent flame retardant performance, discoloration resistance, heat resistance, and corrosion resistance can be improved. Discovered to complete the present invention.

Hereinafter, a method for manufacturing a hypophosphite-based flame retardant according to an aspect of the present invention and a flame retardant prepared therefrom will be described in more detail.

Method for producing a hypophosphite-based flame retardant represented by the following formula (1) according to an aspect of the present invention

(a) a hypophosphite-based metal salt production step of reacting an alkali metal hypophosphite with a 2-4 tetravalent metal salt,

(b) a washing step of washing the hypophosphite-based metal salt prepared in the step (a);

(c) a drying step of vacuum drying the hypophosphite-based metal salt washed in step (b).

It includes,

Any one or more of the steps (a) and (b) is performed including applying ultrasonic energy.

[Formula 1]

(In the above formula 1, R ₁ and R ₂ are independently of each other hydrogen, straight chain or pulverized (C ₁ -C ₆ ) alkyl, M is any metal atom selected from Ca, Mg, Al, Zn and Ti , N represents an integer selected from 2 to 4.)

The method for producing a hypophosphite-based flame retardant according to an aspect of the present invention includes a method using hypophosphite as a raw material or using a metal hypophosphite.

As a specific aspect, a method using hypophosphorous acid as a raw material

Iv) preparing (C ₂ -C ₄ ) alkyl hypophosphorous acid by stirring hypophosphorous acid, (C ₂ -C ₄ ) alkene, radical initiator and water,

Ii) preparing an alkali metal hypophosphite by adding a metal hydroxide to the (C ₂ -C ₄ ) alkyl hypophosphorous acid of step iii),

Iii) a hypophosphite-based metal salt production step of reacting the alkali metal hypophosphite of step ii) with a metal salt of 2 to 4 valent,

Iii) a washing step of washing the hypophosphite-based metal salt prepared in step iii) with water;

Iii) a drying step of vacuum drying the hypophosphite-based metal salt washed in step iii),

At least one of the steps iii) and iii) is characterized in that it is performed under conditions for applying ultrasonic energy.

However, in the case where a hypophosphite-based flame retardant in which hydrogen is substituted instead of an alkyl group by using hypophosphorous acid is directly prepared, the process of step iii) is omitted.

As another aspect, the method using the alkali metal hypophosphite as a raw material

Ⅰ ′) preparing an alkali metal salt of (C ₂ -C ₄ ) alkyl hypophosphite by stirring the alkali metal hypophosphite, (C ₂ -C ₄ ) alkene, a radical initiator and water,

Ii ′) the step (C ₂ -C ₄ ) of the step ⅰ ′) wherein the alkali metal hypoalkyl salt is reacted with a metal salt of 2 to 4 valent hypophosphorous acid metal salt,

Ⅲ ′) a washing step of washing the hypophosphite-based metal salt prepared in step ii ′) with water;

Ⅳ ′) a drying step of vacuum drying the hypophosphite-based metal salt washed in step ⅲ ′),

At least one of the steps ii ′) and ⅲ ′) is characterized in that it is performed under conditions for applying ultrasonic energy.

However, in the case of preparing a hypophosphite-based flame retardant in which hydrogen is substituted instead of an alkyl group by directly using an alkali metal hypophosphite, the process of step ′ ′) is omitted.

According to an aspect of the present invention, the conditions for applying the ultrasonic energy are not greatly limited within a range capable of achieving the desired effect of the present invention, preferably 500 W to 20,000 W per 1,000 L of the reaction solution, More preferably, the output power of 1,000 W to 15,000 W and 10 to 100 KHz, and more preferably 20 to 80 KHz, may be performed within a wavelength range. In addition, the application time of the ultrasonic energy may be 30 minutes to 360 minutes, preferably 60 minutes to 300 minutes. It is possible to increase the purity of the flame retardant in the above range, it is effective in improving productivity and process efficiency, and further, it is more effective in terms of improving physical properties of heat resistance, corrosion resistance and discoloration resistance.

According to an aspect of the present invention, the (C ₂ -C ₄ ) alkene includes at least one selected from alkenes having 2 to 4 carbon atoms, and specifically, ethylene is effective in improving flame retardancy.

According to an aspect of the present invention, the radical initiator is not particularly limited, for example, 2,2-azobis (2-amidinopropene) dihydrochloride, sodium persulfate, potassium persulfate and ammonium persulfate Any one or two or more mixtures selected from the group consisting of can be used. The content of the radical initiator may be 0.5 to 15 mol% compared to hypophosphorous acid, preferably 1 to 10 mol%. Although it is effective in terms of being able to increase the reaction rate in the above range and reduce the cost, this is only a non-limiting example, and is not limited to the above numerical range.

The step iii) is a process for producing (C ₂ -C ₄ ) alkyl hypophosphorous acid, in terms of improving reaction speed and purity, and efficiency of manufacturing equipment, the reaction temperature is 50 to 150 ° C and the reaction pressure is 2 to 10 atm. Good to be maintained, but not necessarily limited to this.

The step ii) is a process of manufacturing a (C ₂ -C ₄ ) alkyl hypophosphite prepared from the hypophosphorous acid or the step iv) with an alkali metal salt to improve the yield of the flame retardant by including the process. It is more effective in terms of finely controlling the particle size.

The step iii) is a (C ₂ -C ₄ ) alkyl hypophosphite alkali metal salt for use as a flame retardant, specifically from a group consisting of nitrates, hydrochlorides, sulfates and mixtures of 2 to 4 metals. It is a process to react with any one component selected. Through this, it is more effective in improving the water resistance together with the synergistic effect of the flame retardant. The 2-4 tetravalent metal salt is, in one embodiment, any one or two or more mixtures selected from the group consisting of aluminum chloride, calcium chloride, magnesium chloride, aluminum sulfate, calcium sulfate, magnesium sulfate, aluminum nitrate, calcium nitrate and magnesium nitrate However, it is not necessarily limited thereto. Preferably, aluminum chloride, aluminum sulfate or aluminum nitrate is more effective in terms of improving heat resistance and water resistance. Aluminum sulfate is more preferably mentioned.

The step iii) is a process for purifying and removing impurities, impurities, and unreacted components contained in the hypophosphite-based metal salt, thereby purifying them. The process may be carried out including washing with distilled water several times, specifically 2 to 4 times, in a temperature range of 50 ° C or higher, specifically 50 to 150 ° C, but is not limited thereto.

According to an aspect of the present invention, the process may be performed under conditions that apply ultrasonic energy. This can increase the removal efficiency of impurities, and can reduce the number of washing cycles, thereby improving the process efficiency and productivity, such as reducing the amount of waste water generated.

Specifically, a metal salt of 2 to 4 of the impurities, for example, sodium sulfate has high hygroscopicity when remaining, thereby increasing the moisture content in the flame retardant product, and the aluminum salt of hypophosphite has the property of being separated from water, and is included inside the non-polar flame retardant crystal As sodium hypophosphite is difficult to access, it is difficult to remove impurities including these components. Thus, by including a water washing process performed under the condition of applying the ultrasonic energy, it is possible to increase the kinetic energy of the water powder to enable penetration into the crystal, and further increase the removal efficiency of the impurities.

In addition, it has properties that can finely control the particle size of the flame retardant. Specifically, sodium hypophosphite itself has a property of agglomerating flame retardant particles, and thus prevents agglomeration of particles through a water washing process performed under conditions to apply the ultrasonic energy, and refines the average particle size of the product by minimizing the particle size. It can be lowered and has the effect of expanding the application to the adhesive field where use is limited due to particle size.

The step iii) is a process of removing water used in the reaction and washing process, and vacuum drying is performed. The conditions for vacuum drying are not particularly limited, but may be specifically performed at 100 to 150 ° C. and 10 mmHg or less. The vacuum drying condition is effective in the above range, but is not particularly limited as long as it can remove moisture to 1% by weight or less.

The hypophosphorous flame retardant according to an aspect of the present invention is represented by the following formula (1).

[Formula 1]

(In the above formula 1, R ₁ and R ₂ are independently of each other hydrogen, straight chain or pulverized (C ₁ -C ₆ ) alkyl, M is any metal atom selected from Ca, Mg, Al, Zn and Ti , N represents an integer selected from 2 to 4.)

In addition, the hypophosphite-based flame retardant according to an aspect of the present invention may satisfy the following relational expression 1.

[Relationship 1]

300 ℃ ≤ T _CG ≤ 400 ℃

(In the above relational expression 1, T _CG is the first temperature at which a weight loss of 1.0% appears under a thermogravimetric analysis condition of a heating rate of 10 ° C / min and a nitrogen flow rate of 20 mL / min.)

The hypophosphite-based flame retardant according to an aspect of the present invention is very excellent in corrosion resistance, heat resistance and discoloration resistance, and can finely control the particle size, so that it is possible to realize excellent physical properties when applied to a thinner adhesive layer. It has the advantage of expanding the scope of application.

It can provide a molded body comprising a hypophosphite-based flame retardant according to an aspect of the present invention, for example, it can be applied to a flexible flat cable (Flexible Flat Cable) or a flexible copper clad laminate (Flexible Copper Clad Laminate), but is necessarily limited to this It is not. Specifically, the hypophosphite-based flame retardant can be applied to the adhesive field. As a specific example, the thickness of the coating layer in the flexible flat cable (FFC) used for electronic materials is limited to use of a flame retardant having a large particle size of about 20 μm. According to an aspect of the present invention, it is applied by easily miniaturizing the particle size. It has easy characteristics.

Hereinafter, a method for manufacturing a hypophosphite-based flame retardant according to the present invention and a hypophosphite-based flame retardant prepared therefrom will be described in more detail through examples. However, the following examples are only one reference for explaining the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

[Production Example 1]

Synthesis of diethyl hypophosphite

1,200 kg (9089.5 mol) of 50% by weight hypophosphite was added to a 3,000 liter high pressure reactor equipped with a stirrer, ethylene was filled to a pressure of 6 Kg / cm 2, then emptied and filled again with ethylene until the same pressure to supply air in the gas phase. Removed. The valve was opened with the ethylene storage tank connected to maintain the pressure during the reaction. 100 kg of ammonium persulfate was dissolved in 400 kg of water in a separately prepared 1,000 L container and continuously injected at a rate of 20 L / hour using a high pressure plunger pump. After the reaction at 70 ° C. for 12 hours, ethylene was no longer consumed, and assuming that the ethylene substitution reaction was completed in this state, the reaction was terminated to obtain a diethyl hypophosphorous acid solution. 200 g of the sample was collected from the solution, cooled to 20 ° C., and water was removed by a rotary evaporator. The sample obtained by filtering the precipitate was subjected to 300 MHz H-NMR analysis to confirm that diethylhypophosphorous acid (DEPA) was synthesized (FIG. 1). The pure DEPA content in the reaction solution was 56.3% by weight.

[Production Example 2]

Synthesis of sodium diethylphosphinate

A diethyl hypophosphite solution (1301.2 kg, 6,000 mol) prepared in Preparation Example 1 in a 5,000 liter stainless steel reactor equipped with a jacket to which steam or cold and hot water can be introduced and equipped with an ultrasonic oscillator (16.2 kW) Was added. Sodium hydroxide (727.3 kg of 33% aqueous solution, 6,000 mol) was slowly added at 25 ° C while stirring the solution. The temperature of the reactor rose to 78 ° C, and cooling water was added to the reactor jacket to cool to 25 ° C.

[Comparative Example 1]

Synthesis of aluminum diethylphosphinate

The temperature of the reactor containing sodium diethylphosphinate prepared in Preparation Example 2 was adjusted to 35 ° C., and aluminum sulfate (Aluminum sulfate, 27 wt% aqueous solution 1,394 kg, 1,100 mol) was slowly added for 60 minutes to react. After carrying out, it was maintained for 60 minutes and then transferred to a filter to perform filtration. 940 kg of distilled water was added, followed by washing with water 4 times, and then 10 kg of undried samples were collected, and the rest was vacuum dried under the conditions of 114 ° C./1.0 mmHg to obtain 727 kg of aluminum diethylphosphinate (yield 94 %).

[Example 1]

50 g of the sample taken in Comparative Example 1 was placed in a 500 mL beaker and 200 g of distilled water was added, followed by sonication with varying output time of 90% in an 800 W Bench Top Sonicator. Examples 1 to 5 are 1 hour, 2 hours, 3 hours, 4 hours and 5 hours ultrasonic treatment, respectively. Then, a part of the sample was taken and compared by measuring the particle size using a laser scattering method (Bettersize Instrument Ltd, model: BT-9300S). As a result, as shown in Table 1 below, the longer the ultrasonic treatment time, the smaller the particle size, and the larger the ultrasonic output, the higher the effect.

division ultrasonic wave
Authorization time
(minute) Ultrasonic power (90%) Ultrasonic power (10%) Particle size (D50%) Granularity (D98%) Particle size (D50%) Granularity (D98%) Comparative Example 1 0 19.20 41.39 19.20 41.39 Example 1 60 13.59 22.16 18.89 40.76 Example 2 120 12.64 28.36 18.53 38.92 Example 3 180 9.50 22.72 17.50 37.98 Example 4 240 8.11 17.61 16.94 37.25 Example 5 300 7.46 16.74 16.62 36.66

[Example 6]

After completion of the input of the aluminum sulfate solution in Comparative Example 1, the output of the ultrasonic oscillator of 16.2 kW was set to 80%, and the same method as in Comparative Example 1 was performed except that the reaction was performed for 1 hour while applying ultrasonic energy. 729 kg of ammonium diethylphosphinate was obtained (yield 93%). As a result, as shown in Table 2 below, it was confirmed that the particle size can be finely adjusted in the case of Example 6 subjected to ultrasonic treatment.

division Particle size (D50%) Granularity (D98%) Remark Comparative Example 1 19.20 41.39 Ultrasonic not applied Example 6 8.90 20.70 Ultrasound application

[Comparative Example 2] Production of aluminum phosphinate

In a 5,000L stainless steel reactor equipped with a jacket that can insert steam or cold / hot water and an ultrasonic oscillator (16.2kW), 1,500kg of distilled water is added and stirred while sodium hypophosphite (Sodium hypophosphite ( SHP) monohydrate) 1,500 kg (14,150 mol) was added, and then the temperature of the reactor was raised to 60 ° C. using steam. After SHP was completely dissolved, 3,260 kg (2,358 mol) of 27 wt% aluminum sulfate was slowly added over 100 minutes, and then the temperature of the reactor was raised to 80 ° C. to react for 6 hours. After the reaction was completed, it was transferred to a filter and filtered. After the filtration was completed, 1050 kg of distilled water was added, followed by washing with water three times, and then 10 kg of undried samples were collected, and the rest was vacuum dried under the condition of 114 ° C./1.0 mmHg to obtain 985 kg of aluminum phosphinate. Obtained (yield about 94%).

[Example 7]

Ultrasonic treatment of aluminum phosphinate (1)

50 g of the sample taken in Comparative Example 2 was placed in a 500 mL beaker, and 200 g of distilled water was added, followed by sonication with varying output time of 90% in an 800 W Bench Top Sonicator. Examples 7 to 11 are 1 hour, 2 hours, 3 hours, 4 hours and 5 hours ultrasonic treatment, respectively. Part of the sample was taken and compared by measuring the particle size using a laser scattering method (Bettersize Instrument Ltd, model: BT-9300S). As a result, as can be seen in Table 3 below, the longer the ultrasonic treatment time, the smaller the particle size, and the higher the ultrasonic output, the higher the effect.

division ultrasonic wave
Application time (minutes) D50 D98 Comparative Example 2 0 103.95 177.34 Example 7 60 92.07 150.18 Example 8 120 89.87 148.56 Example 9 180 89.33 148.29 Example 10 240 88.56 147.81 Example 11 300 70.28 144.09

[Example 12]

Ultrasonic treatment of aluminum phosphinate (2)

After completing the injection of the aluminum sulfate solution in Comparative Example 2, the output of the ultrasonic oscillator of 16.2 kW was set to 80%, and aluminum force was applied in the same manner as in Comparative Example 2, except that the reaction was performed for 1 hour while applying ultrasonic energy. 1,051 kg of aluminate phosphinate was obtained (yield 96%). The apparent specific gravity of the obtained sample was measured (KS M-3002), and the grinding speed by ACM (Air Current Mill) with a rotor diameter of 500 mm and a blow motor capacity of 7.5 kW was measured and compared. As a result, as shown in Table 4 below, in the case of Example 12 sonicated, it was confirmed that the particle size can be finely adjusted and the grinding performance is also improved.

division D50 D98 Apparent weight
(kg / M3) Grinding speed
(kg / hr) Comparative Example 2 87.92 188.41 188.41 35 Example 12 58.54 135.69 135.69 110

[Comparative Example 3 and Examples 12 to 13]

Ultrasonic washing of aluminum diethylphosphinate

100 g of the slurry sample taken in Comparative Example 1 was diluted in 200 g of distilled water, stirred for 20 minutes, and then washed with water. A part of the total 4 times washing process was sonicated with an output of 90% in an 800W Bench Top Sonicator. The sample washed with water 4 times was dried in a drying oven at 115 ° C for 14 hours. The dried sample was subjected to thermogravimetric analysis to compare heat resistance. In addition, each sample was put in an alumina crucible, placed in an electric furnace, left at 300 ° C for 30 minutes, and then taken out. The occurrence of clumping was observed and compared through appearance and touch. As a result, as shown in Table 5, it was confirmed that in Examples 12 and 13 in which ultrasonic treatment was performed during water washing, discoloration prevention was possible and heat resistance was improved. In addition, as shown in FIG. 2, in the case of Comparative Example 3, some yellowing occurred and the entire surface became hard due to aggregation of particles, but in the case of Examples 12 and 13, discoloration did not occur and aggregation did not occur. Did. In addition, as shown in Figure 3, there was a large difference in heat resistance.

division Comparative Example 3 Example 12 Example 13 Ultrasonic washing frequency 0 1st (4th) 2 (1st, 4th) Particle size (D50%) 19.20 14.20 10.20 Granularity (D98%) 41.39 29.36 25.86 Furnace test
(300 ℃, 20 minutes) Some yellowing No discoloration (white) No discoloration (white) Cohesive No aggregation No aggregation TGA heat resistance
(1% loss, ℃) 288 301 351

Although the preferred embodiments of the present invention have been described above, it is clear that the present invention can use various changes, modifications, and equivalents, and can be equally applied by appropriately modifying the above embodiments. Therefore, the above description is not intended to limit the scope of the present invention as defined by the following claims.

Claims (11)

(a) a hypophosphite-based metal salt production step of reacting an alkali metal hypophosphite with a 2-4 tetravalent metal salt,
(b) a washing step of washing the hypophosphite-based metal salt prepared in the step (a);
(c) a drying step of vacuum drying the hypophosphite-based metal salt washed in step (b).
As a method for producing a hypophosphite-based flame retardant of the formula (1) to be prepared, including,
The manufacturing method is a method for producing a hypophosphite-based flame retardant of Chemical Formula 1, which is produced by applying ultrasonic waves in any one or more of steps (a) and (b).
[Formula 1]

(In the formula 1, R ₁ and R ₂ are independently of each other hydrogen, straight chain or pulverized (C ₁ -C ₆ ) alkyl, M is any metal atom selected from Ca, Mg, Al, Zn and Ti , N represents an integer selected from 2 to 4.) According to claim 1,
The divalent tetravalent metal salt is a method for producing a hypophosphite-based flame retardant which is any one selected from the group consisting of nitrate, hydrochloride, sulfate and mixtures of divalent tetravalent metals. According to claim 1,
The ultrasonic energy is applied to the output of 500 to 20,000 W per 1,000 L of the reaction solution and a method for producing a hypophosphite-based flame retardant is performed within a wavelength range of 10 to 100 KHz. According to claim 3,
The application time of the ultrasonic energy is 30 minutes to 360 minutes hypophosphite flame retardant manufacturing method. According to claim 1,
The hypophosphite-based alkali metal salt of step (a) is prepared by adding a metal hydroxide to (C ₂ -C ₄ ) alkyl hypophosphite and stirring the hypophosphite-based flame retardant. The method of claim 5,
The metal hydroxide is a method of manufacturing a hypophosphite-based flame retardant at least one selected from the group consisting of aluminum hydroxide, calcium hydroxide and magnesium hydroxide. The method of claim 5,
The (C ₂ -C ₄ ) alkyl hypophosphorous acid is hypophosphite, (C ₂ -C ₄ ) alkene, a radical initiator and a method for producing a hypophosphorous flame retardant that is prepared by stirring water. delete delete delete delete

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