Flame-retardant polyamide 66 resin and preparation method thereof

Abstract

The invention provides flame-retardant polyamide 66 resin and a preparation method thereof. The flame-retardant polyamide 66 resin is prepared from the following raw materials in parts by weight: 85-98 parts of hexamethylenediamine and adipic acid, 2-8 parts of a phosphorus flame retardant, 1-4 parts of a nitrogen flame retardant, 2-5 parts of a silicon flame retardant and 0.1-2 parts of a third monomer, the molar ratio of the hexamethylenediamine to the adipic acid is (1-1.05): 1. The specific composition of the flame-retardant polyamide 66 resin is designed, and further through the synergistic effect of the phosphorus flame retardant, the nitrogen flame retardant and the silicon flame retardant, the flame-retardant polyamide 66 resin with high flame retardance and good mechanical properties is prepared; meanwhile, the preparation method of the flame-retardant polyamide 66 resin provided by the invention is simple to operate, and the application market of the flame-retardant polyamide 66 resin is expanded.

Description

Technical Field

[0001] The invention belongs to the technical field of flame-retardant polyamide materials, and particularly relates to a flame-retardant polyamide 66 resin and a preparation method thereof. Background Art

[0002] Polyamide 66 has good mechanical properties, wear resistance and chemical corrosion resistance, and is widely used in the fields of engineering plastics and chemical fibers. However, the limiting oxygen index LOI of polyamide 66 material is 22%-24%, which is not a flame retardant material. It also has severe dripping phenomenon during combustion, which can easily expand the fire. Its flammable properties limit its application range.

[0003] Flame retardant polyamide 66 is usually prepared by adding flame retardants to the polyamide system. From the addition mechanism of flame retardants, it can be divided into reactive flame retardants and additive flame retardants. From the chemical composition of flame retardants, it can be divided into halogen flame retardants, phosphorus flame retardants, silicon flame retardants, inorganic flame retardants, and nano-added flame retardants. At the same time, different flame retardants can also be added to the system synergistically to achieve better flame retardant effects. Common synergistic flame retardant systems include antimony-halogen flame retardant systems, phosphorus-halogen flame retardant systems, and phosphorus-nitrogen flame retardant systems. The flame retardant mechanism can be mainly divided into condensed phase flame retardancy, free radical capture, cooling, non-flammable gas, and synergistic effects.

[0004] Halogen flame retardants include bromine and chlorine flame retardants. They are one of the largest organic flame retardants in the world and come in a wide variety. Among them, bromine flame retardants are quite popular due to their excellent performance and moderate price. Halogen flame retardants can effectively reduce the spread of fire when a fire occurs, but the smoke and toxic and corrosive gases produced by their combustion and decomposition will cause secondary damage. Moreover, after halides enter the atmosphere, they are difficult to remove and exist for a long time, destroying the ozone layer.

[0005] Phosphorus-based flame retardants can decompose to generate phosphoric acid during combustion, forming a non-flammable liquid film. At the same time, phosphoric acid is further dehydrated to generate metaphosphoric acid, which is further polymerized to generate polymetaphosphoric acid. In this process, not only does the generated phosphoric acid liquid film have a covering effect, but also because the generated polymetaphosphoric acid is a strong acid and a strong dehydrating agent, it dehydrates the polymer and carbonizes it, changing the mode of the polymer combustion process and forming a carbon film on its surface to isolate the air, thereby exerting a stronger flame retardant effect. Generally, phosphorus-based flame retardants are most effective on oxygen-containing polymers and are mainly used in hydroxyl-containing polymers such as cellulose, polyurethane, and polyester. For hydrocarbon polymers that do not contain oxygen, the effect of phosphorus-based flame retardants is relatively small.

[0006] Silicon flame retardant is an important halogen-free environmentally friendly flame retardant with good thermal stability, water resistance and low toxicity. Silicon flame retardants can be divided into two types: organic silicon and inorganic silicon. Organic silicon flame retardants mainly include silicone oil, silicone resin and silicone rubber, while inorganic silicon flame retardants mainly include silicate and aluminum silicate. Silicon flame retardants can improve the processing performance and mechanical strength of polymers while giving them excellent flame retardancy and smoke suppression.

[0007] The phosphorus-nitrogen system can achieve a synergistic flame retardant effect. At high temperatures, it will synergistically form an expandable coke layer on the surface of the object, which acts as a heat-insulating and oxygen-barrier protective layer. Among them, the nitride acts as a foaming agent and a coke enhancer, and the phosphide provides an acid source, which reacts with the resin to promote the formation of carbonized products. In addition, the nitride can also provide a gas source to expand and foam the system, which also promotes the formation of the carbonized layer, forming a porous foam carbon layer. Moreover, the silicon-based flame retardant can promote the formation of carbon during combustion, forming a dense silicon-carbon layer.

[0008] CN106987117A discloses a technical solution for preparing flame-retardant polyamide by compounding phosphorus-nitrogen flame retardants, which increases the glow-wire ignition temperature of the melamine cyanurate system to above 750°C and greatly improves the flame retardant effect. However, the flame retardant is added by melt blending, the uniformity of the flame retardant is questionable, and secondary processing is required, which is complicated.

[0009] In the prior art, the addition of flame retardants may reduce the mechanical properties of polyamide materials. Therefore, how to provide a polyamide material with both high flame retardancy and good mechanical properties has become a technical problem that needs to be solved urgently. Summary of the invention

[0010] In view of the deficiencies of the prior art, the purpose of the present invention is to provide a flame retardant polyamide 66 resin and a preparation method thereof. The present invention designs the specific composition of the flame retardant polyamide 66 resin, and further prepares a flame retardant polyamide 66 resin having both high flame retardancy and good mechanical properties through the synergistic effect of phosphorus flame retardants, nitrogen flame retardants and silicon flame retardants; at the same time, the preparation method of the flame retardant polyamide 66 resin provided by the present invention is simple to operate, which expands the application market of the flame retardant polyamide 66 resin.

[0011] To achieve this object, the present invention adopts the following technical solutions:

[0012] In a first aspect, the present invention provides a flame retardant polyamide 66 resin, wherein the raw materials for preparing the flame retardant polyamide 66 resin include the following components in parts by weight:

[0013] 85-98 parts of hexamethylenediamine and adipic acid, 2-8 parts of phosphorus flame retardant, 1-4 parts of nitrogen flame retardant, 2-5 parts of silicon flame retardant and 0.1-2 parts of the third monomer;

[0014] The molar ratio of hexamethylenediamine to adipic acid is (1-1.05):1.

[0015] The present invention designs the specific composition of the flame-retardant polyamide 66 resin, and further improves the flame retardancy of the polyamide 66 resin through the synergistic effect of a phosphorus-based flame retardant, a nitrogen-based flame retardant and a silicon-based flame retardant, so that the flame retardancy grade of the polyamide 66 resin reaches V-0, and improves the droplet problem of the polyamide 66 resin, while retaining the original good mechanical properties of the polyamide 66 resin, thereby preparing a flame-retardant polyamide 66 resin with both high flame retardancy and good mechanical properties.

[0016] In the present invention, the comprehensive performance of the flame retardant polyamide 66 resin is optimized through the synergistic effect of phosphorus-based flame retardants, nitrogen-based flame retardants and silicon-based flame retardants in a specific dosage range.

[0017] In the present invention, the mechanical properties of the flame retardant polyamide 66 resin are improved by using the third monomer and controlling the amount of the third monomer within a specific range. If the amount of the third monomer is too small, it cannot improve the material performance; if the amount of the third monomer is too large, the third monomer is likely to form oligomers and become plasticizers, reducing the mechanical strength of the material.

[0018] In the present invention, in the raw materials for preparing the flame retardant polyamide 66 resin, the sum of the weight parts of hexamethylenediamine and adipic acid can be 85 parts, 86 parts, 87 parts, 88 parts, 89 parts, 90 parts, 91 parts, 92 parts, 93 parts, 94 parts, 95 parts, 96 parts, 97 parts or 98 parts, etc.

[0019] In the raw materials for preparing the flame retardant polyamide 66 resin, the weight proportion of the phosphorus-based flame retardant can be 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts or 8 parts, etc.

[0020] In the raw materials for preparing the flame-retardant polyamide 66 resin, the weight proportion of the nitrogen-based flame retardant can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts or 4 parts.

[0021] In the raw materials for preparing the flame retardant polyamide 66 resin, the weight proportion of the silicon-based flame retardant can be 2 parts, 2.2 parts, 2.5 parts, 2.7 parts, 3 parts, 3.3 parts, 3.5 parts, 3.8 parts, 4 parts, 4.2 parts, 4.4 parts, 4.6 parts or 5 parts, etc.

[0022] In the raw materials for preparing the flame retardant polyamide 66 resin, the weight proportion of the third monomer can be 0.1 parts, 0.2 parts, 0.4 parts, 0.6 parts, 0.8 parts, 1 parts, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts or 2 parts, etc.

[0023] The molar ratio of hexamethylenediamine to adipic acid is (1-1.05):1, for example, 1:1, 1.01:1, 1.02:1, 1.03:1, 1.04:1 or 1.05:1.

[0024] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0025] As a preferred technical solution of the present invention, the phosphorus-based flame retardant is selected from 3-hydroxyphenylphosphoryl propionic acid and / or aminotrimethylene phosphonic acid aluminum (NYP3).

[0026] As a preferred technical solution of the present invention, the nitrogen-based flame retardant is selected from melamine cyanurate (MCA) and / or melamine, preferably melamine cyanurate (MCA).

[0027] As a preferred technical solution of the present invention, the silicon-based flame retardant is selected from silicone resin powder and / or silicone oil, preferably silicone resin powder.

[0028] In the present invention, the flame retardancy of the polyamide 66 resin is improved by the synergistic effect of the specific phosphorus-based flame retardant, the nitrogen-based flame retardant and the silicon-based flame retardant.

[0029] The present invention further optimizes the comprehensive performance of polyamide 66 resin, further improves the flame retardant property of polyamide 66 resin, and improves the droplet problem of polyamide 66 resin by using 3-hydroxyphenylphosphoryl propionic acid and / or aminotrimethylene phosphonic acid aluminum, melamine cyanurate, and silicone resin micropowder as components.

[0030] As a preferred technical solution of the present invention, the third monomer is selected from any one of caprolactam, sebacic acid or dodecanedioic acid, or a combination of at least two thereof.

[0031] The present invention further optimizes the comprehensive performance of polyamide 66 resin by using a specific third monomer.

[0032] As a preferred technical solution of the present invention, the raw materials for preparing the flame retardant polyamide 66 resin also include 0.1-1 parts by weight of antioxidant, for example, 0.1 parts by weight, 0.2 parts by weight, 0.3 parts by weight, 0.4 parts by weight, 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight or 1 part by weight.

[0033] Preferably, the antioxidant is selected from any one of antioxidant H10, antioxidant AO3349, antioxidant H161, antioxidant H3373, antioxidant H1010, antioxidant H1098 or dilauryl thiodipropionate, or a combination of at least two thereof.

[0034] Preferably, the raw materials for preparing the flame retardant polyamide 66 salt also include 0.2-1 parts by weight of a heat stabilizer, for example, 0.2 parts by weight, 0.3 parts by weight, 0.4 parts by weight, 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight or 1 part by weight.

[0035] Preferably, the heat stabilizer is selected from any one of copper acetate-potassium iodide, copper acetate-cuprous iodide-potassium iodide, copper acetate-potassium bromide or copper acetate-cuprous bromide-potassium bromide, or a combination of at least two thereof.

[0036] It should be noted that, in the present invention, cupric acetate-potassium iodide represents a combination of cupric acetate and potassium iodide. Similarly, cupric acetate-cuprous iodide-potassium iodide represents a combination of cupric acetate, cuprous iodide and potassium iodide. Cupric acetate-potassium bromide represents a combination of cupric acetate and potassium bromide. Cupric acetate-cuprous bromide-potassium bromide represents a combination of cupric acetate, cuprous bromide and potassium bromide.

[0037] Preferably, the raw materials for preparing the flame retardant polyamide 66 salt also include 0.01-0.1 parts by weight of a catalyst, for example, 0.01 parts by weight, 0.05 parts by weight, 0.1 parts by weight, 0.2 parts by weight, 0.3 parts by weight, 0.4 parts by weight, 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight or 1 part by weight.

[0038] Preferably, the catalyst is selected from any one or a combination of at least two of phosphoric acid, phosphorous acid, hypophosphorous acid-based organic matter or hypophosphite.

[0039] It should be noted that the present invention does not have any special restrictions on the specific selection of hypophosphorous acid-based organic substances and hypophosphites. Hypophosphorous acid-based organic substances and hypophosphites commonly used in the art are applicable, and exemplary examples include but are not limited to sodium hypophosphite.

[0040] In a second aspect, the present invention provides a method for preparing the flame retardant polyamide 66 resin as described in the first aspect, wherein the method for preparing the flame retardant polyamide 66 resin comprises the following steps:

[0041] (1) hexamethylenediamine and adipic acid react to form a salt, and adjust the pH to obtain a polyamide 66 salt solution;

[0042] (2) The polyamide 66 salt solution and other raw materials for preparing the flame-retardant polyamide 66 are mixed and reacted to obtain the flame-retardant polyamide 66 resin.

[0043] As a preferred technical solution of the present invention, the temperature of the salt-forming reaction is 50°C to 80°C (for example, it can be 50°C, 52°C, 55°C, 57°C, 60°C, 63°C, 66°C, 68°C, 70°C, 72°C, 75°C, 77°C or 80°C), and the time is 20min to 30min (for example, it can be 20min, 21min, 22min, 23min, 24min, 25min, 26min, 27min, 28min, 29min or 30min, etc.).

[0044] Preferably, the salt-forming reaction is carried out in a protective gas atmosphere and in the presence of a solvent, and the solvent includes water.

[0045] In the present invention, the protective gas atmosphere can be an argon atmosphere or a nitrogen atmosphere.

[0046] Preferably, after pH adjustment, the pH of the polyamide 66 salt solution is 7.00-7.80, for example, 7.00, 7.10, 7.20, 7.30, 7.40, 7.50, 7.60, 7.70 or 7.80.

[0047] In the present invention, adipic acid or hexamethylenediamine can be added to the reaction system as in step (1) to adjust the pH of the reaction system.

[0048] Preferably, the mass percentage of the polyamide 66 salt solution is 40% to 60%, for example, it can be 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58% or 60%.

[0049] As a preferred technical solution of the present invention, the mixing temperature in step (2) is 50°C to 80°C, for example, it can be 50°C, 52°C, 55°C, 57°C, 60°C, 63°C, 66°C, 68°C, 70°C, 72°C, 75°C, 77°C or 80°C.

[0050] Preferably, the reaction in step (2) comprises the following steps: heating the reaction system until the pressure of the reaction system reaches 0.15MPa to 0.20MPa (for example, 0.15MPa, 0.155MPa, 0.16MPa, 0.165MPa, 0.17MPa, 0.175MPa, 0.18MPa, 0.185MPa, 0.19MPa, 0.195MPa or 0.20MPa, etc.), concentrating the mass concentration of the polyamide 66 salt solution to 60% to 70% (for example, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, 101%, 102%, 103%, 104%, 105%, 106%, 107%, 108%, 109%, 110%, 111%, 112%, 113%, 114%, 115%, 116%, 117%, 118%, 119%, 120%, 121%, 122%, 123%, 124%, 125%, 126%, 127%, 128%, 129%, 130%, 131%, 132%, 133%, 134%, 135%, 67%, 68%, 69% or 70%, etc.); continue to heat up until the pressure of the reaction system is 0.8MPa-1.3MPa (for example, it can be 0.8MPa, 0.85MPa, 0.9MPa, 0.95MPa, 1MPa, 1.05MPa, 1.1MPa, 1.15MPa, 1.2MPa, 1.25MPa or 1.3MPa, etc.), and the mass of the polyamide 66 salt solution is concentrated to 70%-90% (for example, it can be 70%, 72%, 74%, 76%, 78%, 80%, 82%, 84%, 86%, 88% or 90%, etc.); continue to heat up until the reaction system is After the pressure reaches 1.6 MPa to 2.0 MPa (for example, 1.6 MPa, 1.65 MPa, 1.7 MPa, 1.75 MPa, 1.8 MPa, 1.85 MPa, 1.9 MPa, 1.95 MPa or 2.0 MPa, etc.), the mass concentration of the polyamide 66 salt solution is concentrated to 92% to 97% (for example, 92%, 93%, 94%, 95%, 96% or 97%, etc.), the temperature is increased, the pressure is reduced, and the water is discharged, and the pressure of the reaction system is reduced to normal pressure, and the reaction mixture is heated at 260° C. to 290° C. (for example, 260° C., 265° C., 270° C., 275° C., 280° C., 285° C.) The polymerization reaction is carried out for 5 min to 30 min (for example, 5 min, 7 min, 10 min, 12 min, 15 min, 18 min, 20 min, 23 min, 25 min, 27 min or 30 min) under the conditions of 290°C and 290°C) and a pressure of -0.01 MPa to -0.1 MPa (for example, it can be -0.01 MPa, -0.02 MPa, -0.03 MPa, -0.04 MPa, -0.05 MPa, -0.06 MPa, -0.07 MPa, -0.08 MPa, -0.09 MPa or -0.1 MPa, etc.).

[0051] As a preferred technical solution of the present invention, the preparation method of the flame retardant polyamide 66 resin specifically comprises the following steps:

[0052] (1) In a protective gas atmosphere, hexamethylenediamine, adipic acid and water are mixed, and a salt-forming reaction is carried out at 50° C. to 80° C. for 20 min to 30 min, and the pH is adjusted to 7.00 to 7.80 to obtain a polyamide 66 salt solution with a mass concentration of 40% to 60%;

[0053] (2) at 50°C to 80°C, a polyamide 66 salt solution and other raw materials for preparing flame-retardant polyamide 66 are mixed, and the temperature is increased. When the pressure of the reaction system reaches 0.15MPa to 0.20MPa, the mass concentration of the polyamide 66 salt solution is concentrated to 60% to 70%; the temperature is further increased until the pressure of the reaction system reaches 0.8MPa to 1.3MPa, and the mass of the polyamide 66 salt solution is concentrated to 70% to 90%; the temperature is further increased until the pressure of the reaction system reaches 1.6MPa to 2.0MPa, and after the mass concentration of the polyamide 66 salt solution is concentrated to 92% to 97%, the temperature is increased, the pressure is reduced, and the water is drained, and the pressure of the reaction system is reduced to normal pressure. A polymerization reaction is carried out at 260°C to 290°C and a pressure of -0.01MPa to -0.1MPa for 5min to 30min to obtain the flame-retardant polyamide 66 resin.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] The present invention designs the specific composition of the flame retardant polyamide 66 resin, and further prepares the flame retardant polyamide 66 resin having both high flame retardancy and good mechanical properties through the synergistic effect of phosphorus flame retardants, nitrogen flame retardants and silicon flame retardants; at the same time, the preparation method of the flame retardant polyamide 66 resin provided by the present invention is simple to operate, thereby expanding the application market of the flame retardant polyamide 66 resin. DETAILED DESCRIPTION

[0056] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0057] The sources of some components in the embodiments and comparative examples are as follows:

[0058] Silicone resin powder: Ningbo Jinlei Nanomaterial Technology Co., Ltd., JL-SiO2-GY300;

[0059] Silicone oil: Momentive High-Tech Materials Group, TSF4708;

[0060] Antioxidant H10: Shanghai Newo Chemical Technology Co., Ltd., BRUGGOLEN H10.

[0061] Example 1

[0062] This embodiment provides a flame retardant polyamide 66 resin and a preparation method thereof. The raw materials for preparing the flame retardant polyamide 66 resin include the following components in parts by weight:

[0063] 87 parts of hexamethylenediamine and adipic acid, 6 parts of 3-hydroxyphenylphosphoryl propionic acid, 2 parts of melamine cyanurate, 4 parts of silicone resin powder, 0.15 parts of antioxidant H10, 0.6 parts of caprolactam, 0.2 parts of potassium iodide, 0.02 parts of cupric acetate, and 0.03 parts of sodium hypophosphite;

[0064] The molar ratio of hexamethylenediamine to adipic acid is 1:1.

[0065] The preparation method of the flame retardant polyamide 66 resin is as follows:

[0066] (1) putting hexamethylenediamine and adipic acid into a salting kettle, adding pure water, and performing salting at 60° C. in a nitrogen atmosphere, and adjusting the pH value to 7.30 after salting to obtain a polyamide 66 salt solution with a mass concentration of 50%;

[0067] (2) the polyamide 66 salt solution obtained in step (1) is put into a polymerization kettle, and then 3-hydroxyphenylphosphoryl propionic acid, melamine cyanurate, silicone resin powder, antioxidant H10, caprolactam, potassium iodide, copper acetate, and sodium hypophosphite are sequentially put into the polymerization kettle for nitrogen replacement. After the nitrogen replacement is completed, the polymerization kettle is heated up, and when the pressure in the kettle reaches 0.20 MPa, the concentrated salt solution is drained and the mass concentration of the polyamide 66 salt solution is concentrated to 65%; the temperature is continued to be raised, and when the pressure in the polymerization kettle reaches 1 .1MPa, drain and concentrate to concentrate the mass concentration of polyamide 66 salt solution to 80%; continue to heat up, and when the pressure in the polymerization kettle reaches 1.8MPa, drain and concentrate to concentrate the mass concentration of polyamide 66 salt solution to 95%; then increase the temperature and reduce the pressure to drain, and when the temperature in the kettle reaches 280°C and the pressure in the polymerization kettle drops to normal pressure, start negative pressure polymerization, pump the system to -0.05MPa, continue the reaction for 10 minutes, and then discharge the material through the discharge port to obtain the flame retardant polyamide 66 resin.

[0068] Example 2

[0069] This embodiment provides a flame retardant polyamide 66 resin and a preparation method thereof. The raw materials for preparing the flame retardant polyamide 66 resin include the following components in parts by weight:

[0070] 92 parts of hexamethylenediamine and adipic acid, 3 parts of 3-hydroxyphenylphosphorylpropionic acid, 1 part of melamine cyanurate, 2 parts of silicone resin powder, 0.45 parts of antioxidant H10, 1 part of sebacic acid, 0.4 parts of potassium iodide, 0.05 parts of cupric acetate, and 0.1 parts of sodium hypophosphite;

[0071] The molar ratio of hexamethylenediamine to adipic acid is 1:1.

[0072] The preparation method of the flame retardant polyamide 66 resin is the same as that of Example 1.

[0073] Example 3

[0074] This embodiment provides a flame retardant polyamide 66 resin and a preparation method thereof. The raw materials for preparing the flame retardant polyamide 66 resin include the following components in parts by weight:

[0075] 85 parts of hexamethylenediamine and adipic acid, 6 parts of 3-hydroxyphenylphosphoryl propionic acid, 4 parts of melamine cyanurate, 4 parts of silicone resin powder, 0.15 parts of antioxidant H10, 0.6 parts of dodecanedioic acid, 0.2 parts of potassium iodide, 0.02 parts of cupric acetate, and 0.03 parts of sodium hypophosphite;

[0076] The molar ratio of hexamethylenediamine to adipic acid is 1:1.

[0077] The preparation method of the flame retardant polyamide 66 resin is the same as that of Example 1.

[0078] Example 4

[0079] This embodiment provides a flame retardant polyamide 66 resin and a preparation method thereof, which is different from Embodiment 1 only in that:

[0080] Replacing melamine cyanurate with an equal weight portion of melamine;

[0081] Other conditions are the same as in Example 1.

[0082] Example 5

[0083] This embodiment provides a flame retardant polyamide 66 resin and a preparation method thereof, which is different from Embodiment 1 only in that:

[0084] Replace the silicone resin powder with an equal amount of silicone oil by weight;

[0085] Other conditions are the same as in Example 1.

[0086] Example 6

[0087] This embodiment provides a flame retardant polyamide 66 resin and a preparation method thereof, which is different from Embodiment 1 only in that:

[0088] The 3-hydroxyphenylphosphatopropionic acid is replaced by an equal amount of aminotrimethylene aluminum phosphate;

[0089] Other conditions are the same as in Example 1.

[0090] Example 7

[0091] This embodiment provides a flame retardant polyamide 66 resin and a preparation method thereof, which is different from Embodiment 1 only in that:

[0092] Step (1): after salt formation, adjusting the pH value to 7.10;

[0093] Other conditions are the same as in Example 1.

[0094] Example 8

[0095] This embodiment provides a flame retardant polyamide 66 resin and a preparation method thereof, which is different from Embodiment 1 only in that:

[0096] Step (1): after salt formation, adjusting the pH value to 7.60;

[0097] Other conditions are the same as in Example 1.

[0098] Example 9

[0099] This embodiment provides a flame retardant polyamide 66 resin and a preparation method thereof, which is different from Embodiment 1 only in that:

[0100] Step (2): After the system is pumped down to -0.05 MPa, the reaction is continued for 20 min;

[0101] Other conditions are the same as in Example 1.

[0102] Example 10

[0103] This embodiment provides a flame retardant polyamide 66 resin and a preparation method thereof. The raw materials for preparing the flame retardant polyamide 66 resin include the following components in parts by weight:

[0104] 87.5 parts of hexamethylenediamine and adipic acid, 6 parts of 3-hydroxyphenylphosphorylpropionic acid, 2 parts of melamine cyanurate, 4 parts of silicone resin powder, 0.15 parts of antioxidant H10, 0.1 parts of caprolactam, 0.2 parts of potassium iodide, 0.02 parts of cupric acetate, and 0.03 parts of sodium hypophosphite;

[0105] The molar ratio of hexamethylenediamine to adipic acid is 1:1.

[0106] The preparation method of the flame retardant polyamide 66 resin is the same as that of Example 1.

[0107] Embodiment 11

[0108] This embodiment provides a flame retardant polyamide 66 resin and a preparation method thereof. The raw materials for preparing the flame retardant polyamide 66 resin include the following components in parts by weight:

[0109] 85.6 parts of hexamethylenediamine and adipic acid, 6 parts of 3-hydroxyphenylphosphorylpropionic acid, 2 parts of melamine cyanurate, 4 parts of silicone resin powder, 0.15 parts of antioxidant H10, 2 parts of caprolactam, 0.2 parts of potassium iodide, 0.02 parts of cupric acetate, and 0.03 parts of sodium hypophosphite;

[0110] The molar ratio of hexamethylenediamine to adipic acid is 1:1.

[0111] The preparation method of the flame retardant polyamide 66 resin is the same as that of Example 1.

[0112] Example 12

[0113] This embodiment provides a flame retardant polyamide 66 resin and a preparation method thereof, which is different from Embodiment 1 only in that:

[0114] Replace caprolactam with an equal amount of sebacic acid by weight;

[0115] Other conditions are the same as in Example 1.

[0116] Comparative Example 1

[0117] This comparative example provides a flame retardant polyamide 66 resin and a preparation method thereof. The raw materials for preparing the flame retardant polyamide 66 resin include the following components in parts by weight:

[0118] 87.6 parts of hexamethylenediamine and adipic acid, 6 parts of 3-hydroxyphenylphosphoryl propionic acid, 2 parts of melamine cyanurate, 4 parts of silicone resin powder, 0.15 parts of antioxidant H10, 0.2 parts of potassium iodide, 0.02 parts of copper acetate, and 0.03 parts of sodium hypophosphite;

[0119] The molar ratio of hexamethylenediamine to adipic acid is 1:1.

[0120] The preparation method of the flame retardant polyamide 66 resin is the same as that of Example 1.

[0121] Comparative Example 2

[0122] This comparative example provides a flame retardant polyamide 66 resin and a preparation method thereof. The raw materials for preparing the flame retardant polyamide 66 resin include the following components in parts by weight:

[0123] 85.1 parts of hexamethylenediamine and adipic acid, 6 parts of 3-hydroxyphenylphosphoryl propionic acid, 2 parts of melamine cyanurate, 4 parts of silicone resin powder, 0.15 parts of antioxidant H10, 2.5 parts of caprolactam, 0.2 parts of potassium iodide, 0.02 parts of cupric acetate, and 0.03 parts of sodium hypophosphite;

[0124] The molar ratio of hexamethylenediamine to adipic acid is 1:1.

[0125] The preparation method of the flame retardant polyamide 66 resin is the same as that of Example 1.

[0126] Comparative Example 3

[0127] This comparative example provides a flame retardant polyamide 66 resin and a preparation method thereof. The raw materials for preparing the flame retardant polyamide 66 resin include the following components in parts by weight:

[0128] 98 parts of hexamethylenediamine and adipic acid, 0.15 parts of antioxidant H10, 2.5 parts of caprolactam, 0.2 parts of potassium iodide, 0.02 parts of copper acetate, and 0.03 parts of sodium hypophosphite;

[0129] The molar ratio of hexamethylenediamine to adipic acid is 1:1.

[0130] The preparation method of the flame retardant polyamide 66 resin is as follows:

[0131] (1) putting hexamethylenediamine and adipic acid into a salting kettle, adding pure water, and performing salting at 60° C. in a nitrogen atmosphere, and adjusting the pH value to 7.30 after salting to obtain a polyamide 66 salt solution with a mass concentration of 50%;

[0132] (2) The polyamide 66 salt solution obtained in step (1) is put into a polymerization kettle and replaced with nitrogen. After the nitrogen replacement is completed, the polymerization kettle is heated. When the pressure in the kettle reaches 0.20 MPa, the saline solution is concentrated by draining water to 65% by mass concentration. The temperature is continued to be raised. When the pressure in the polymerization kettle reaches 1.1 MPa, the saline solution is concentrated by draining water to 80% by mass concentration. The temperature is continued to be raised. When the pressure in the polymerization kettle reaches 1.8 MPa, the saline solution is concentrated by draining water to 95% by mass concentration. The temperature is then raised and the pressure is reduced. When the temperature in the kettle reaches 280° C. and the pressure in the polymerization kettle drops to normal pressure, negative pressure polymerization is started. The system is pumped to −0.05 MPa and the reaction is continued for 10 min. The material is then discharged through the feed port to obtain the flame retardant polyamide 66 resin.

[0133] Comparative Example 4

[0134] This comparative example provides a flame retardant polyamide 66 resin and a preparation method thereof. The raw materials for preparing the flame retardant polyamide 66 resin include the following components in parts by weight:

[0135] 87 parts of hexamethylenediamine and adipic acid, 4 parts of melamine cyanurate, 8 parts of silicone resin powder, 0.15 parts of antioxidant H10, 0.6 parts of caprolactam, 0.2 parts of potassium iodide, 0.02 parts of copper acetate, and 0.03 parts of sodium hypophosphite;

[0136] The molar ratio of hexamethylenediamine to adipic acid is 1:1.

[0137] The preparation method of the flame retardant polyamide 66 resin is the same as that of Example 1.

[0138] Comparative Example 5

[0139] This comparative example provides a flame retardant polyamide 66 resin and a preparation method thereof. The raw materials for preparing the flame retardant polyamide 66 resin include the following components in parts by weight:

[0140] 87 parts of hexamethylenediamine and adipic acid, 9 parts of 3-hydroxyphenylphosphorylpropionic acid, 3 parts of melamine cyanurate, 0.15 parts of antioxidant H10, 0.6 parts of caprolactam, 0.2 parts of potassium iodide, 0.02 parts of cupric acetate, and 0.03 parts of sodium hypophosphite;

[0141] The molar ratio of hexamethylenediamine to adipic acid is 1:1.

[0142] The preparation method of the flame retardant polyamide 66 resin is the same as that of Example 1.

[0143] Comparative Example 6

[0144] This comparative example provides a flame retardant polyamide 66 resin and a preparation method thereof. The raw materials for preparing the flame retardant polyamide 66 resin include the following components in parts by weight:

[0145] 87 parts of hexamethylenediamine and adipic acid, 7.2 parts of 3-hydroxyphenylphosphoryl propionic acid, 0.15 parts of antioxidant H10, 0.6 parts of caprolactam, 0.2 parts of potassium iodide, 0.02 parts of cupric acetate, and 0.03 parts of sodium hypophosphite;

[0146] The molar ratio of hexamethylenediamine to adipic acid is 1:1.

[0147] The preparation method of the flame retardant polyamide 66 resin is the same as that of Example 1.

[0148] The properties of the flame retardant polyamide 66 resin provided in the above embodiments and comparative examples were tested, and the specific testing method is as follows:

[0149] (1) Relative viscosity test: The test was conducted using the concentrated sulfuric acid method using an Ubbelohde viscometer. The specific steps were as follows: 0.30±0.0002 g of the dried flame-retardant polyamide 66 resin sample was weighed, 30 mL of concentrated sulfuric acid (mass concentration of 96%) was added, and the sample solution was dissolved at 60°C to obtain a sample solution. The concentrated sulfuric acid flow time t0 and the sample solution flow time t were weighed and recorded in a 25°C constant temperature water bath.

[0150] Relative viscosity η r =t / t0.

[0151] (2) Melting point: The samples were tested at an ambient temperature of 23±2°C and a humidity of 50±5% RH using a differential scanning calorimeter (DSC) according to the test standard “IS0 11357-3:2011 Plastics Differential Scanning Calorimetry (DSC) Part 3: Melting and Solidification Temperature and Enthalpy”.

[0152] (3) Tensile strength: measured according to ISO 527-2 method, the tensile speed during the test is 50 mm / min.

[0153] (4) Flexural strength: measured according to ISO 178 method, test condition is 2 mm / min.

[0154] (5) Notched impact strength: The notched impact strength of the material was tested using a cantilever pendulum impact tester. The impact strength was measured according to the IS0180-2001 method, with a notch depth of 2 mm and a pendulum energy of 2.75 J.

[0155] (6) Flame retardant grade test: The center of the flame is placed at the midpoint of the lower edge of the sample, with the distance from the top of the burner to the lower end of the sample being 10 mm. This is maintained for 10 seconds. If the shape and position of the sample change during the combustion process, the burner should be adjusted accordingly. If molten material drips during the test, the burner can be tilted to 45°. After burning for 10±0.5 seconds, move away from the burner at least 150 mm at a speed of 300 mm / min. At the same time, start recording the afterflame time t1 (seconds). When the afterflame stops, immediately burn again for 10±0.5 seconds. After moving away, record the afterflame time t2 (seconds) and afterburning time t3 (seconds), and record the number of molten droplets. The flame retardant grade is determined based on whether the molten droplets ignite the absorbent cotton.

[0156]

[0157] Each example provides 5 samples for testing and recording.

[0158] The performance test results are shown in Table 1 and Table 2

[0159] Table 1

[0160]

[0161] Table 2

[0162]

[0163]

[0164]

[0165] As can be seen from Table 1, the present invention designs the raw materials for preparing the flame-retardant polyamide 66 resin. Compared with the polyamide 66 resin without any flame retardant, the mechanical properties of the polyamide 66 resin containing phosphorus flame retardant, nitrogen flame retardant and silicon flame retardant provided by the present invention are not significantly reduced, and the relative viscosity is 2.62-2.76, the melting point is 261°C or 262°C, the tensile strength is 74-79MPa, the flexural strength is 90-94MPa, and the notched impact strength is 4.3-5.1KJ / m 2 .

[0166] It can be seen from Table 2 that, compared with the polyamide 66 resin without any flame retardant, the flame retardant grade of the polyamide 66 resin containing phosphorus flame retardant, nitrogen flame retardant and silicon flame retardant provided by the present invention is improved from V2 to V0, and the number of droplets is also significantly reduced (the number of droplets is ≤11), and the flame retardant effect of the group with nitrogen flame retardant, silicon flame retardant and phosphorus flame retardant added is better than that of the group without flame retardant and the group with only two flame retardants added, and the flame retardant effect of the system can be regulated by adjusting the ratio of the flame retardant.

[0167] The present invention further optimizes the comprehensive performance of polyamide 66 resin by using 3-hydroxyphenylphosphoryl propionic acid and / or aminotrimethylene phosphonic acid aluminum, melamine cyanurate, and silicone resin micropowder as components, further improves the flame retardant performance of polyamide 66 resin, and improves the droplet problem of polyamide 66 resin, wherein the droplet number is ≤7.

[0168] The present invention further optimizes and improves the comprehensive performance of the flame retardant polyamide 66 resin by using a specific third monomer and controlling the amount of the third monomer within a specific range.

[0169] In summary, the present invention designs the specific composition of the flame-retardant polyamide 66 resin, and further prepares the flame-retardant polyamide 66 resin having both high flame retardancy and good mechanical properties through the synergistic effect of phosphorus-based flame retardants, nitrogen-based flame retardants and silicon-based flame retardants; at the same time, the preparation method of the flame-retardant polyamide 66 resin provided by the present invention is simple to operate, which expands the application market of the flame-retardant polyamide 66 resin.

[0170] The applicant declares that the present invention illustrates the detailed process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A flame retardant polyamide 66 resin, characterized in that: The raw materials for preparing the flame retardant polyamide 66 resin include the following components in parts by weight: 85-98 parts of hexamethylenediamine and adipic acid, 2-8 parts of phosphorus flame retardant, 1-4 parts of nitrogen flame retardant, 2-5 parts of silicon flame retardant and 0.1-2 parts of the third monomer; The molar ratio of hexamethylenediamine to adipic acid is (1-1.05):

1.

2. The flame retardant polyamide 66 resin according to claim 1, characterized in that: The phosphorus-based flame retardant is selected from 3-hydroxyphenylphosphoryl propionic acid and / or aminotrimethylene aluminum phosphonate.

3. The flame retardant polyamide 66 resin according to claim 1 or 2, characterized in that: The nitrogen-based flame retardant is selected from melamine cyanurate and / or melamine, preferably melamine cyanurate.

4. The flame retardant polyamide 66 resin according to any one of claims 1 to 3, characterized in that: The silicon-based flame retardant is selected from silicone resin powder and / or silicone oil, preferably silicone resin powder.

5. The flame retardant polyamide 66 resin according to any one of claims 1 to 4, characterized in that: The third monomer is selected from any one of caprolactam, sebacic acid or dodecanedioic acid, or a combination of at least two thereof.

6. The flame retardant polyamide 66 resin according to any one of claims 1 to 5, characterized in that: The raw materials for preparing the flame retardant polyamide 66 resin also include 0.1 to 1 parts by weight of an antioxidant; Preferably, the raw materials for preparing the flame retardant polyamide 66 resin further include 0.2 to 1 parts by weight of a heat stabilizer; Preferably, the heat stabilizer is selected from any one or a combination of at least two of copper acetate-potassium iodide, copper acetate-cuprous iodide-potassium iodide, copper acetate-potassium bromide or copper acetate-cuprous bromide-potassium bromide; Preferably, the raw materials for preparing the flame retardant polyamide 66 resin further include 0.01 to 0.1 parts by weight of a catalyst; Preferably, the catalyst is selected from any one or a combination of at least two of phosphoric acid, phosphorous acid, hypophosphorous acid-based organic matter or hypophosphite.

7. A method for preparing the flame retardant polyamide 66 resin according to any one of claims 1 to 6, characterized in that: The preparation method of the flame retardant polyamide 66 resin comprises the following steps: (1) hexamethylenediamine and adipic acid react to form a salt, and adjust the pH to obtain a polyamide 66 salt solution; (2) The polyamide 66 salt solution and other raw materials for preparing the flame-retardant polyamide 66 are mixed and reacted to obtain the flame-retardant polyamide 66 resin.

8. The preparation method according to claim 7, characterized in that: The temperature of the salt-forming reaction is 50°C to 80°C, and the time is 20min to 30min; Preferably, the salt-forming reaction is carried out in a protective gas atmosphere and in the presence of a solvent, wherein the solvent includes water; Preferably, after adjusting the pH, the pH of the polyamide 66 salt solution is 7.00 to 7.80; Preferably, the mass percentage of the polyamide 66 salt solution is 40% to 60%.

9. The preparation method according to claim 7 or 8, characterized in that: The mixing temperature in step (2) is 50° C. to 80° C.; Preferably, the reaction in step (2) comprises the following steps: heating the reaction system until the pressure of the reaction system reaches 0.15MPa-0.20MPa, concentrating the mass concentration of the polyamide 66 salt solution to 60%-70%; continuing to heat the reaction system until the pressure reaches 0.8MPa-1.3MPa, concentrating the mass of the polyamide 66 salt solution to 70%-90%; continuing to heat the reaction system until the pressure reaches 1.6MPa-2.0MPa, concentrating the mass concentration of the polyamide 66 salt solution to 92%-97%, then heating and reducing the pressure to drain the water, reducing the pressure of the reaction system to normal pressure, and carrying out a polymerization reaction at 260°C-290°C and a pressure of -0.01MPa--0.1MPa for 5min-30min.

10. The preparation method according to any one of claims 7 to 9, characterized in that: The preparation method of the flame retardant polyamide 66 resin specifically comprises the following steps: (1) In a protective gas atmosphere, hexamethylenediamine, adipic acid and water are mixed, and a salt-forming reaction is carried out at 50° C. to 80° C. for 20 min to 30 min, and the pH is adjusted to 7.00 to 7.80 to obtain a polyamide 66 salt solution with a mass concentration of 40% to 60%; (2) at 50°C to 80°C, a polyamide 66 salt solution and other raw materials for preparing flame-retardant polyamide 66 are mixed, and the temperature is increased. When the pressure of the reaction system reaches 0.15MPa to 0.20MPa, the mass concentration of the polyamide 66 salt solution is concentrated to 60% to 70%; the temperature is further increased until the pressure of the reaction system reaches 0.8MPa to 1.3MPa, and the mass of the polyamide 66 salt solution is concentrated to 70% to 90%; the temperature is further increased until the pressure of the reaction system reaches 1.6MPa to 2.0MPa, and after the mass concentration of the polyamide 66 salt solution is concentrated to 92% to 97%, the temperature is increased, the pressure is reduced, and the water is drained, and the pressure of the reaction system is reduced to normal pressure. A polymerization reaction is carried out at 260°C to 290°C and a pressure of -0.01MPa to -0.1MPa for 5min to 30min to obtain the flame-retardant polyamide 66 resin.

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