1. The composite antimony-series flame retardant is characterized in that the composite antimony-series flame retardant is coated with oleic acid, and the composite antimony-series flame retardant consists of an inorganic antimony-series flame retardant, an organic phosphinic acid metal salt and metal-MOFs.

2. The antimony-based composite flame retardant according to claim 1, wherein the mass ratio of the inorganic antimony-based flame retardant, the organic phosphinic acid metal salt and the metal-MOFs is 2 to 2.5: 1: 5-8.

3. The antimony-based composite flame retardant according to claim 1, wherein the inorganic antimony-based flame retardant is antimony trioxide, antimony pentoxide, antimony oxychloride or sodium antimonate.

4. The antimony-based composite flame retardant according to claim 1, wherein the metal salt of organic phosphinic acid is a metal dialkylphosphinate, a metal alkylaryl phosphinate or a metal diarylphosphinate.

5. The antimony-based composite flame retardant according to claim 4, wherein the metal salt of organic phosphinic acid is any one or a combination of plural kinds of metal salts of dimethyl phosphinic acid, metal salt of methyl ethyl phosphinic acid, metal salt of diethyl phosphinic acid, metal salt of methyl cyclohexyl phosphinic acid, metal salt of ethyl cyclohexyl phosphinic acid, metal salt of dicyclohexylphosphinic acid, metal salt of methyl propionic acid, metal salt of ethyl propionic acid, metal salt of methyl phenyl phosphinic acid, metal salt of ethyl phenyl phosphinic acid, and metal salt of diphenyl phosphinic acid.

6. The antimony-based composite flame retardant according to claim 5, wherein the organic phosphinic acid metal salt is an aluminum salt, a magnesium salt or a calcium salt of dimethylphosphinic acid; aluminum, magnesium or calcium salts of methylethylphosphinic acid; aluminum, magnesium or calcium salts of diethylphosphinic acid; aluminum, magnesium or calcium salts of methylcyclohexylphosphinic acid; aluminum, magnesium or calcium salts of ethylcyclohexylphosphinic acid; aluminum, magnesium or calcium salts of dicyclohexylphosphinic acid; aluminum, magnesium or calcium salts of methylpropionatephosphinic acid; aluminum, magnesium or calcium salts of ethylpropionylphosphinic acid; aluminum, magnesium or calcium salts of methylphenylphosphinic acid; aluminum, magnesium or calcium salts of ethylphenylphosphinic acid; any one or more of aluminum, magnesium or calcium salts of diphenylphosphinic acid.

7. The antimony-based composite flame retardant of claim 1, wherein the metal-MOFs is Co-MOFs, Zn-MOFs or Ni-MOFs.

8. The antimony-based composite flame retardant of claim 1, wherein the metal-MOFs is prepared by the following method:

adding metal salt and terephthalic acid into a DMF/ethanol/water solution, performing ultrasonic dispersion, then mechanically stirring at room temperature for 1-3h, placing the reaction solution in a reaction kettle, reacting at 160-200 ℃ for 40-60h, cooling the reaction solution, performing suction filtration, washing the solid with absolute ethyl alcohol, and then drying in vacuum.

9. The method for preparing an antimony-based composite flame retardant according to any one of claims 1 to 8, comprising the steps of:

adding metal-MOFs and an auxiliary agent into water, stirring for 30-50min at the speed of 150r/min for 100-.

10. The method for preparing an antimony-based composite flame retardant according to claim 9, wherein the auxiliary agent is composed of glucose, sodium lauryl sulfate, and polyvinylpyrrolidone.

Background

Flame retardants are substances that increase the flame resistance of polymeric materials, primarily polymeric materials such as plastics, rubbers, fibers, etc., most of which are combustible. In particular, in order to apply the plastic to transportation, construction, electrical equipment, aviation, space flight and the like, the problem of combustion resistance is urgently needed to be solved. The flame retardant is generally used under the following conditions: the physical properties of the high polymer material, such as heat resistance, mechanical strength and electrical performance, are not reduced; the decomposition temperature is not too high, and the decomposition is not carried out at the processing temperature; the durability is good; the weather resistance is good; it is cheap.

Among them, inorganic flame retardants have been favored in flame retardants because of their characteristics of simple production process, little environmental pollution, abundant and easily available raw materials, low production cost, and the like. Among them, antimony-based flame retardants have a very good synergistic effect with halogen flame retardants, and thus occupy a very important position in inorganic flame retardants. On one hand, the halogen flame retardant can release toxic gas while retarding flame of the polymer, and the halogen flame retardant is harmful to the environment and the human health, and on the other hand, the antimony flame retardant is mainly antimony trioxide which is unevenly dispersed in a high polymer material and can influence the physical mechanical property and the optical property of the material when being added into the high polymer material, so that the application range of the antimony flame retardant is greatly limited. Therefore, it is an urgent need in the art to re-compound the antimony-based flame retardant and improve the dispersibility of the antimony-based flame retardant in the polymer material.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the defects or improvement requirements of the prior art, the invention provides an antimony composite flame retardant and a preparation method thereof.

The technical scheme adopted by the invention is as follows:

an antimony-based composite flame retardant is coated with oleic acid on the outside and comprises an inorganic antimony-based flame retardant, an organic phosphinate metal salt and metal-MOFs on the inside.

Further, the mass ratio of the inorganic antimony flame retardant, the organic phosphinic acid metal salt and the metal-MOFs is 2-2.5: 1: 5-8.

Furthermore, the inorganic antimony flame retardant is antimony trioxide, antimony pentoxide, antimony oxychloride or sodium antimonate, is the flame retardance of the antimony flame retardant, improves the surface smoothness of molded products, extruded products and film products, reduces the using amount and smoke generation amount of the antimony flame retardant, and preferably has the grain diameter of less than or equal to 0.1 mu m, wherein the antimony trioxide can be selected in a nanometer level.

Further, the metal salt of organic phosphinic acid is a metal salt of dialkylphosphinic acid, a metal salt of alkylaryl phosphinic acid, or a metal salt of diarylphosphinic acid.

Further, the organic phosphinic acid metal salt is any one or a combination of plural kinds of a dimethyl phosphinic acid metal salt, a methyl ethyl phosphinic acid metal salt, a diethyl phosphinic acid metal salt, a methyl cyclohexyl phosphinic acid metal salt, an ethyl cyclohexyl phosphinic acid metal salt, a dicyclohexyl phosphinic acid metal salt, a methyl propionic acid group phosphinic acid metal salt, an ethyl propionic acid group phosphinic acid metal salt, a methyl phenyl phosphinic acid metal salt, an ethyl phenyl phosphinic acid metal salt and a diphenyl phosphinic acid metal salt.

Further, the metal salt of organic phosphinic acid is an aluminum salt, a magnesium salt or a calcium salt of dimethyl phosphinic acid; aluminum, magnesium or calcium salts of methylethylphosphinic acid; aluminum, magnesium or calcium salts of diethylphosphinic acid; aluminum, magnesium or calcium salts of methylcyclohexylphosphinic acid; aluminum, magnesium or calcium salts of ethylcyclohexylphosphinic acid; aluminum, magnesium or calcium salts of dicyclohexylphosphinic acid; aluminum, magnesium or calcium salts of methylpropionatephosphinic acid; aluminum, magnesium or calcium salts of ethylpropionylphosphinic acid; aluminum, magnesium or calcium salts of methylphenylphosphinic acid; aluminum, magnesium or calcium salts of ethylphenylphosphinic acid; any one or more of aluminum, magnesium or calcium salts of diphenylphosphinic acid.

The organic phosphinic acid metal salt is preferably aluminum diethylphosphinate, aluminum methylcyclohexylphosphinate or aluminum methylethylphosphinate.

Further, the metal-MOFs is Co-MOFs, Zn-MOFs or Ni-MOFs.

Preferably Co-MOFs or Ni-MOFs, more preferably Co-MOFs.

Further, the preparation method of the metal-MOFs is as follows:

adding metal salt and terephthalic acid into a DMF/ethanol/water solution, performing ultrasonic dispersion, then mechanically stirring at room temperature for 1-3h, placing the reaction solution in a reaction kettle, reacting at 160-200 ℃ for 40-60h, cooling the reaction solution, performing suction filtration, washing the solid with absolute ethyl alcohol, and then drying in vacuum.

The preparation method of the antimony compound flame retardant comprises the following steps:

adding metal-MOFs and an auxiliary agent into water, stirring for 30-50min at the speed of 150r/min for 100-.

Furthermore, the auxiliary agent consists of glucose, sodium dodecyl sulfate and polyvinylpyrrolidone.

Furthermore, the auxiliary agent consists of glucose, sodium dodecyl sulfate and polyvinylpyrrolidone in a mass ratio of 1-3:1-3: 1-3.

The invention has the beneficial effects that:

the invention provides an antimony-based composite flame retardant, the exterior of which is coated by oleic acid, the interior of which consists of an inorganic antimony-based flame retardant, an organic metal phosphinate and metal-MOFs, wherein the organic metal phosphinate forms a coke layer through polymer combustion, so that the heat conductivity of the polymer is weakened, the heat obtained on the surface of the polymer is effectively prevented, the further decomposition of the polymer is slowed down, a P-O-C bond in the organic metal phosphinate generates a cross-linking reaction at high temperature to generate a net-shaped compound, active free radicals supporting combustion are captured, so that the combustion is inhibited, after the inorganic antimony-based flame retardant is compounded with the inorganic antimony-based flame retardant, a synergistic effect can be exerted, the flame-retardant and smoke-suppression efficiency is improved, the MOFs are inorganic-organic porous materials with periodic network structures formed by organic ligands and metal ions or clusters through coordination bonds, the specific surface area is large, the interaction force between the organic ligands and polymer molecular chains in the MOFs is strong, the flame retardant has good affinity with a polymer chain, can generate metal oxide after being coordinated with metal and is favorable for reducing smoke emission and promoting carbon formation, and when the flame retardant is prepared, the amphiphilic auxiliary agent is added, so that the inorganic antimony flame retardant, the organic metal phosphinate and the metal-MOFs are tightly combined into an organic whole, and the oleic acid coating is also favorable for improving the dispersibility of the organic whole.

Detailed Description

The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

Example 1:

the composite antimony-series fire retardant is coated with oleic acid and consists of nanometer antimony trioxide, aluminum diethylphosphinate and Co-MOFs.

Wherein the mass ratio of the nano antimony trioxide, the aluminum diethylphosphinate and the Co-MOFs is 2.5: 1: 6.

the preparation method of the Co-MOFs comprises the following steps:

mixing Co (NO)₃)₂And terephthalic acid is mixed according to the mass ratio of 1.6: 1, adding the mixture into a sufficient amount of DMF/ethanol/water solution (the volume ratio of DMF to ethanol to water is 3:1:1), ultrasonically dispersing the mixture for 30min at 400W, mechanically stirring the mixture for 2h at room temperature of 200r/min, transferring the reaction solution into a sealed high-pressure reaction kettle, heating the reaction solution to 165 ℃ for reacting for 45h, cooling the reaction solution, performing suction filtration, washing the solid with absolute ethanol for 3 times, and then performing vacuum drying at 60 ℃.

The preparation method of the antimony compound flame retardant comprises the following steps:

adding Co-MOFs and an auxiliary agent (composed of glucose, sodium dodecyl sulfate and polyvinylpyrrolidone in a mass ratio of 1:1: 1) into water, stirring for 50min at 100r/min to obtain a dispersion A, adding nano antimony trioxide into the water, stirring for 50min at 100r/min to obtain a dispersion B, adding aluminum diethylphosphinate into the water, stirring for 50min at 100r/min to obtain a dispersion C, dropwise adding the dispersion B into the dispersion A, stirring for 50min at 250r/min, dropwise adding the dispersion C, stirring for 50min at 250r/min, adjusting the rotation speed to 800r/min, stirring vigorously for 15h, adding oleic acid, adjusting the pH of the system to 10 by using ammonia water, heating to 50 ℃ for reaction for 1h, recovering the room temperature, carrying out suction filtration, washing the solid by using ethanol, and carrying out vacuum drying.

Example 2:

the composite antimony-series fire retardant is coated with oleic acid and consists of nanometer antimony trioxide, methyl cyclohexyl aluminum phosphinate and Co-MOFs.

Wherein the mass ratio of the nano antimony trioxide to the methyl cyclohexyl aluminum phosphinate to the Co-MOFs is 2:1: 5.

the preparation method of the Co-MOFs comprises the following steps:

mixing Co (NO)₃)₂And terephthalic acid is mixed according to the mass ratio of 1.6: 1, adding the mixture into a sufficient amount of DMF/ethanol/water solution (the volume ratio of DMF to ethanol to water is 3:1:1), ultrasonically dispersing the mixture for 30min at 400W, mechanically stirring the mixture for 2h at room temperature of 200r/min, transferring the reaction solution into a sealed high-pressure reaction kettle, heating the reaction solution to 165 ℃ for reacting for 45h, cooling the reaction solution, performing suction filtration, washing the solid with absolute ethanol for 3 times, and then performing vacuum drying at 60 ℃.

The preparation method of the antimony compound flame retardant comprises the following steps:

adding Co-MOFs and an auxiliary agent (composed of glucose, sodium dodecyl sulfate and polyvinylpyrrolidone in a mass ratio of 1:1: 2) into water, stirring for 50min at 150r/min to obtain a dispersion A, adding nano antimony trioxide into water, stirring for 50min at 150r/min to obtain a dispersion B, adding methyl cyclohexyl aluminum phosphinate into water, stirring for 50min at 150r/min to obtain a dispersion C, dropwise adding the dispersion B into the dispersion A, stirring for 50min at 250r/min, dropwise adding the dispersion C, stirring for 50min at 250r/min, adjusting the rotation speed to 600r/min, stirring vigorously for 15h, adding oleic acid, adjusting the pH of the system to 10 with ammonia water, heating to 55 ℃ for reaction for 1h, recovering the room temperature, carrying out suction filtration, washing the solid with ethanol, and carrying out vacuum drying.

Example 3:

the composite antimony-series fire retardant is coated with oleic acid and consists of nanometer antimony trioxide, aluminum diethylphosphinate and Ni-MOFs.

Wherein the mass ratio of the nano antimony trioxide, the aluminum diethylphosphinate and the Ni-MOFs is 2.5: 1: 8.

the preparation method of the Ni-MOFs comprises the following steps:

mixing Ni (NO)₃)₂And terephthalic acid is mixed according to the mass ratio of 1.6: 1, adding the mixture into a sufficient amount of DMF/ethanol/water solution (the volume ratio of DMF to ethanol to water is 3:1:1), ultrasonically dispersing the mixture for 30min at 400W, mechanically stirring the mixture for 2h at room temperature of 200r/min, transferring the reaction solution into a sealed high-pressure reaction kettle, heating the reaction solution to 165 ℃ for reacting for 45h, cooling the reaction solution, performing suction filtration, washing the solid with absolute ethanol for 3 times, and then performing vacuum drying at 60 ℃.

The preparation method of the antimony compound flame retardant comprises the following steps:

adding Ni-MOFs and an auxiliary agent (composed of glucose, sodium dodecyl sulfate and polyvinylpyrrolidone in a mass ratio of 3:1:1) into water, stirring for 30min at 100r/min to obtain a dispersion A, adding nano antimony trioxide into the water, stirring for 30min at 100r/min to obtain a dispersion B, adding aluminum diethylphosphinate into the water, stirring for 30min at 100r/min to obtain a dispersion C, dropwise adding the dispersion B into the dispersion A, stirring for 50min at 200r/min, dropwise adding the dispersion C, stirring for 30min at 250r/min, adjusting the rotation speed to 600r/min, stirring vigorously for 15h, adding oleic acid, adjusting the pH of the system to 10 by using ammonia water, heating to 50 ℃ for reaction for 1h, recovering the room temperature, carrying out suction filtration, washing the solid by using ethanol, and carrying out vacuum drying.

Example 4:

the composite antimony-series fire retardant is coated with oleic acid and consists of nanometer antimony trioxide, methyl ethyl aluminum phosphinate and Co-MOFs.

Wherein the mass ratio of the nano antimony trioxide, the methyl ethyl aluminum phosphinate and the Co-MOFs is 2:1: 8.

the preparation method of the Co-MOFs comprises the following steps:

mixing Co (NO)₃)₂And terephthalic acid is mixed according to the mass ratio of 2:1 adding the mixture into a sufficient amount of DMF/ethanol/water solution (the volume ratio of DMF to ethanol to water is 3:1:1), ultrasonically dispersing the mixture for 30min at 400W, mechanically stirring the mixture for 2h at room temperature of 200r/min, transferring the reaction solution into a sealed high-pressure reaction kettle, heating the reaction solution to 165 ℃ for reaction for 45h, cooling the reaction solution, performing suction filtration, washing the solid with absolute ethanol for 3 times, and then drying the solid in vacuum at 60 ℃.

The preparation method of the antimony compound flame retardant comprises the following steps:

adding Co-MOFs and an auxiliary agent (composed of glucose, sodium dodecyl sulfate and polyvinylpyrrolidone in a mass ratio of 1:1: 1) into water, stirring for 30min at 150r/min to obtain a dispersion A, adding nano antimony trioxide into water, stirring for 30min at 150r/min to obtain a dispersion B, adding methyl ethyl aluminum phosphinate into water, stirring for 30min at 150r/min to obtain a dispersion C, dropwise adding the dispersion B into the dispersion A, stirring for 30min at 200r/min, dropwise adding the dispersion C, stirring for 30min at 200r/min, adjusting the rotation speed to 600r/min, stirring vigorously for 12h, adding oleic acid, adjusting the pH of the system to 10 by using ammonia water, heating to 50 ℃ for reaction for 1h, recovering the room temperature, carrying out suction filtration, washing the solid by using ethanol, and carrying out vacuum drying.

Example 5:

the composite antimony-series fire retardant is coated with oleic acid and consists of nanometer antimony trioxide, aluminum diethylphosphinate and Co-MOFs.

Wherein the mass ratio of the nano antimony trioxide, the aluminum diethylphosphinate and the Co-MOFs is 2.7: 1: 5.5.

the preparation method of the Co-MOFs comprises the following steps:

mixing Co (NO)₃)₂And terephthalic acid is mixed according to the mass ratio of 1.8: 1 adding the mixture into a sufficient amount of DMF/ethanol/water solution (the volume ratio of DMF to ethanol to water is 3:1:1), ultrasonically dispersing the mixture for 30min at 400W, mechanically stirring the mixture for 2h at room temperature of 200r/min, transferring the reaction solution into a sealed high-pressure reaction kettle, heating the reaction solution to 165 ℃ for reaction for 45h, cooling the reaction solution, performing suction filtration, washing the solid with absolute ethanol for 3 times, and then drying the solid in vacuum at 60 ℃.

The preparation method of the antimony compound flame retardant comprises the following steps:

adding Co-MOFs and an auxiliary agent (composed of glucose, sodium dodecyl sulfate and polyvinylpyrrolidone in a mass ratio of 2:1: 2) into water, stirring for 50min at 150r/min to obtain a dispersion A, adding nano antimony trioxide into water, stirring for 50min at 150r/min to obtain a dispersion B, adding aluminum diethylphosphinate into water, stirring for 50min at 150r/min to obtain a dispersion C, dropwise adding the dispersion B into the dispersion A, stirring for 50min at 200r/min, dropwise adding the dispersion C, stirring for 50min at 250r/min, adjusting the rotation speed to 800r/min, stirring vigorously for 10h, adding oleic acid, adjusting the pH of the system to 10 by using ammonia water, heating to 50 ℃ for reaction for 1h, recovering the room temperature, carrying out suction filtration, washing the solid with ethanol, and carrying out vacuum drying.

Comparative example 1

Comparative example 1 is essentially the same as example 1 except that no nano antimony trioxide was added.

Comparative example 2

Comparative example 2 is essentially the same as example 1 except that aluminum diethylphosphinate was not added.

Comparative example 3

Comparative example 3 is essentially the same as example 1 except that no Co-MOFs were added.

Comparative example 4

Comparative example 4 is essentially the same as example 1 except that no oleic acid coating was added as prepared.

Comparative example 5

Comparative example 5 is essentially the same as example 1 except that no adjuvant was added during the preparation.

And (3) performance test:

the flame retardants prepared in examples 1-5 and comparative examples 1-4 of the invention, PA-6 and an auxiliary agent are uniformly mixed (the dosage of the flame retardant is 1% of the mass of the PA-6), and then the mixture is added into a double-screw extruder for extrusion granulation to obtain flame-retardant nylon, and the flame-retardant nylon is subjected to injection molding to prepare sample strips with various sizes and then is placed at normal temperature for 24 hours for testing.

The blank was not flame retardant added, and the rest was the same as above.

The impact performance is tested according to GB/T1043-2008, the size of the sample strip is 80mm multiplied by 10mm multiplied by 4mm, and the gap is a V-shaped gap with the depth of 2 mm;

the tensile property is tested according to GB/T1040-2006, the size of a standard sample strip is a 1A type dumbbell-shaped standard sample strip with the thickness of 4mm, and the testing speed is 50 mm/min;

the bending property is tested according to GB/T9341-2008, the size of a sample strip is 80mm multiplied by 10mm multiplied by 4mm, and the testing speed is 2 mm/min;

the mechanical properties of the blank sample bars were tested and compared with those of the flame retardant sample bars prepared by adding examples 1-5 and comparative examples 1-5, and the rate of change in mechanical properties was calculated, wherein "+" is an increase and "-" is a decrease, and the results are shown in Table 1 below.

Table 1:

as shown in the table 1, the flame retardant can play a role in toughening and reinforcing PA-6 after being added, and the mechanical property of the PA-6 is improved to a certain extent, and the comparison of a comparative example 4 and examples 1-5 shows that the dispersion uniformity between the flame retardant and a PA-6 material is improved after the flame retardant is coated by oleic acid, and the mechanical property of the PA-6 material is improved by introducing second-phase flame retardant particles into a PA-6 material matrix.

Performance test 2:

and (3) testing the smoke suppression and flame retardant properties: the horizontal and vertical combustion is tested according to GB/T2408-2008, the oxygen index is tested according to GB/T2406.1-2008, the cone calorimetric property is tested according to ISO5660-12007, and the sample heat radiation power is 50kW/m²The results are shown in table 2 below:

table 2:

as shown in the table 2, the flame retardant can play a role in inhibiting smoke and retarding flame for PA-6 after being added, the LOI is more than or equal to 36 percent, the smoke-inhibiting flame-retarding grade is V-0, no molten drop exists during combustion, the ignition time is more than or equal to 43s, and the smoke-inhibiting effect is good.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.