Intrinsically flame-retardant high-temperature polyamide copolymer and preparation method thereof

Abstract

The present invention relates to an intrinsically flame-retardant high-temperature polyamide copolymer and its preparation method. A flame retardant prepolymer and a high-temperature polyamide are copolymerized to form a copolymer. This copolymer not only meets flame retardancy requirements but also significantly improves drip resistance, achieving flame retardancy levels up to UL94V0. The mechanical properties, particularly toughness, of the high-temperature polyamide remain unchanged.

Description

Technical Field

[0001] The invention belongs to the technical field of high-temperature polyamide materials and relates to an intrinsic flame-retardant high-temperature polyamide copolymer and a preparation method thereof. Background Art

[0002] As electric vehicles increasingly demand high temperature resistance from materials and electronic appliances become increasingly miniaturized and multifunctional, the materials industry is accelerating the industrialization of high-temperature polyamides to meet these demands. However, due to their flammability, high-temperature polyamides require the addition of flame retardants to achieve the required flame retardancy. Currently, high-temperature polyamides typically use additive flame retardants, particularly halogen flame retardants, to achieve flame retardancy. However, halogen flame retardants produce large amounts of toxic and harmful gases, including some that are highly carcinogenic, during combustion, limiting their use. Therefore, halogen-free flame retardants have become a research hotspot for high-temperature polyamide flame retardancy.

[0003] Finding suitable halogen-free flame retardants for high-temperature polyamides (HPAMs) is challenging. High-temperature polyamides have high melting points, and processing temperatures typically range from 310°C to 350°C. This makes halogen-free flame retardants like MCA insufficient due to their insufficient thermal stability. Alkyl hypophosphites, especially aluminum diethylphosphinate, can meet these processing conditions and are therefore commonly used as flame retardants for these materials (e.g., US7294661B2, PCT / US2008 / 068971, US20100261818A1, US20120029124A1, PCT / US2013 / 049040, and US20140011925A1). However, aluminum diethylphosphinate is corrosive, especially at high temperatures, causing significant corrosion to equipment during processing. Furthermore, these additives significantly reduce the mechanical properties, especially toughness, of HPAMs. This results in mechanical properties failing to meet required standards despite achieving flame retardancy.

[0004] Therefore, the study of adding a halogen-free reactive flame retardant to the high-temperature polyamide polymerization process to copolymerize to form a halogen-free intrinsically flame-retardant high-temperature polyamide has become a hot topic. JP2001270993A describes DiDOPO, a derivative of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO). The DiDOPO described in this patent has a longer bridge chain than the vinyl bridge chain and good flame retardancy, but it will cause the heat deformation temperature of the product to decrease. WO2010135398A1 reports a derivative of DOPO (DiDOPO), which contains two phosphorus centers in each molecule and has good thermal stability and flame retardancy. However, no matter which reactive flame retardant is added, it will inevitably lead to a decrease in the mechanical properties of the high-temperature polyamide, and the phenomenon of molten droplets cannot be well solved. Summary of the Invention

[0005] To address the above technical issues, the present invention provides an intrinsically flame-retardant high-temperature polyamide copolymer, its preparation method, and its application. This copolymer exhibits excellent flame retardancy, thermal stability, and chemical stability. It overcomes the shortcomings of existing DiDOPO flame retardants, such as insufficient heat resistance and dripping resistance, without compromising the mechanical properties of high-temperature polyamide. The halogen-free, intrinsically flame-retardant high-temperature polyamide prepared by the present invention achieved a UL94 V-0 rating in a vertical combustion test with a thickness of 0.8 mm.

[0006] 1. Intrinsically flame retardant high temperature polyamide copolymer

[0007] In one aspect, the present invention provides an intrinsically flame-retardant high-temperature polyamide copolymer, which can be represented by the following structural formula:

[0008] -[AB] n -

[0009] in,

[0010] A represents a high-temperature polyamide segment;

[0011] B represents a flame retardant prepolymer segment;

[0012] n represents the number of polymer segments,

[0013] The mass ratio of the high temperature polyamide segment to the flame retardant prepolymer segment may be 19:1-3:1, more preferably 9:1-4:1.

[0014] High temperature polyamide segment

[0015] Polyamide, also known as nylon or nylon, is a general term for polymers containing the amide group -NH-C(O)- in their structural units. They are synthesized through the condensation or ring-opening reaction of one or more dicarboxylic acids and one or more diamines, and / or one or more amino acids, and / or one or more lactams. Based on the composition of their backbone, polyamides are generally classified as aliphatic, aromatic, and semi-aromatic.

[0016] High temperature polyamide (HTPA) is a heat-resistant polyamide and an engineering plastic that can be used in an environment of 150°C for a long time.

[0017] There is no particular restriction on the type of high temperature polyamide segment, including but not limited to PA 6T, PA 9T, PA 8T, PA10T, PA 12T, PA 6I, PA 8I, PA 9I, PA 10I, PA 12I, PA 6T / 6, PA 6T / 12, PA 6T / 6I, PA 6T / 8T, PA 6T / 9T, PA 6T / 12T, PA 12T / 6T, PA 6T / 6I / 6, PA 6T / 6I / 12, PA 6T / 6I / 610, PA 6T / 6I / 612, PA 6T / 66, PA 6T / 610, PA 6T / 612, PA 10T / 6, PA 10T / 12, PA 8T / 6T, PA 8T / 66, PA 8T / 8I, PA 8T / 86, PA PA 8T / 6I, PA 10T / 6T, PA 10T / 66, PA 10T / 10I, PA 10T / 6I, PA 4T / 4I / 46, PA4T / 4I / 66, PA 5T / 5I, PA 5T / 5I / 56, PA 5T / 5I / 66, PA 6T / 6I / 66, PA MXDA6 and their copolymers and mixtures.

[0018] In an embodiment, the high temperature polyamide segment can be represented by the following structural formula:

[0019] or

[0020] wherein the P1 unit is derived from at least one aromatic dibasic acid (preferably an aromatic dibasic acid having 2 to 12 carbon atoms), and optionally at least one aliphatic dibasic acid (preferably an aliphatic dibasic acid having 2 to 12 carbon atoms);

[0021] The P2 unit is derived from at least one aromatic diamine (preferably an aromatic diamine having 2 to 12 carbon atoms), or at least one aliphatic diamine (preferably an aliphatic diamine having 2 to 12 carbon atoms);

[0022] The L unit is derived from a lactam (preferably a lactam having 4 to 12 carbon atoms);

[0023] n1 represents the degree of polymerization.

[0024] In an embodiment, the weight average molecular weight of the high temperature polyamide segment may be 10,000-40,000, preferably 25,000-35,000.

[0025] In an embodiment, the molar ratio of P1 units to P2 units is 1:1-1.1, preferably 1:1.01-1.08; or

[0026] The molar ratio of the P1 unit, the P2 unit and the L unit is 1:1-1.1:0.8-1.1, preferably 1:1.01-1.08:0.8-1.0.

[0027] Flame retardant prepolymer segment

[0028] In an embodiment, the flame retardant prepolymer segment can be represented by the following structural formula:

[0029] or

[0030] The A1 unit is derived from the structure shown in formula (1):

[0031]

[0032] wherein R1 and R2 are each independently selected from -O- or -NH-;

[0033] Unit D1 is derived from:

[0034] The F1 unit is derived from: an aliphatic diamine or aromatic diamine having 2 to 12 carbon atoms, and / or an aliphatic dibasic acid or aromatic dibasic acid having 2 to 12 carbon atoms;

[0035] n2 represents the degree of polymerization.

[0036] In an embodiment, the weight average molecular weight of the flame retardant prepolymer segment may be 10,000-30,000, preferably 15,000-20,000.

[0037] In an embodiment, the molar ratio of A1 unit to D1 unit is 2:1-1.1, preferably 2:1; or

[0038] The molar ratio of the A1 unit, the D1 unit and the F1 unit is 2:1-1.1:0.8-1.1, preferably 2:1:1.

[0039] 2. Preparation method of intrinsic flame retardant high temperature polyamide copolymer

[0040] Another aspect of the present invention provides a method for preparing the intrinsically flame-retardant high-temperature polyamide copolymer, comprising the following steps:

[0041] (a1) providing a high temperature polyamide and a flame retardant prepolymer;

[0042] (a2) copolymerizing the high-temperature polyamide and the flame retardant prepolymer to obtain an intrinsically flame-retardant high-temperature polyamide copolymer.

[0043] 2.1 Flame retardant prepolymer

[0044] Except for the -NH2 and -COOH groups at both ends of the prepolymer, the general description of the flame retardant prepolymer is the same as that of the aforementioned flame retardant prepolymer segment section and will not be repeated here.

[0045] In some embodiments, the flame retardant prepolymer is obtained by salification and prepolymerization of a flame retardant monomer composition, wherein the flame retardant monomer composition includes a diamine and a dibasic acid, the diamine includes 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and optionally other diamines, and the dibasic acid includes flame retardant A and optionally other dibasic acids.

[0046] The structure of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane is as follows:

[0047]

[0048] There is no particular limitation on the source of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, which can be commercially available or prepared according to a known method.

[0049] The flame retardant A has a structure as shown in formula (1):

[0050]

[0051] wherein R1 and R2 are each independently selected from -O- or -NH-.

[0052] In some embodiments, the flame retardant A is selected from one or more of the following compounds:

[0053]

[0054] There is no particular limitation on the source of flame retardant A, which can be commercially available or prepared according to existing known methods.

[0055] In some embodiments, the other diamines are aliphatic diamines having 2-12 carbon atoms (such as butanediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octanediamine, nonanediamine) or aromatic diamines, and the other dibasic acids are aliphatic dibasic acids having 2-12 carbon atoms (such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid) or aromatic dibasic acids.

[0056] In some embodiments, the molar ratio of the dibasic acid to the diamine in the flame retardant monomer composition is 1:1.001-1.1, more preferably 1:1.005-1.05; the molar ratio of flame retardant A in the flame retardant monomer composition is not less than 50%, and the molar ratio of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane in the flame retardant monomer composition is not less than 20%.

[0057] In some embodiments, the flame retardant prepolymer is prepared by a method comprising the following steps:

[0058] The flame retardant monomer composition, catalyst, antioxidant and water are added into a polymerization kettle to carry out salt-forming reaction to obtain a flame retardant salt; the flame retardant salt is heated to carry out prepolymerization reaction to obtain a flame retardant prepolymer.

[0059] There are no particular limitations on the catalyst and antioxidant; any known additive for acid-amine salt polycondensation reactions can be used. The catalyst can be selected from one or a combination of sodium phosphate, magnesium phosphate, calcium phosphate, magnesium phosphite, calcium phosphite, zinc phosphite, and sodium hypophosphite. Preferably, the catalyst is sodium hypophosphite. The antioxidant can be selected from one or a combination of 1098, 168, 1010, 1076, and copper salts. Preferably, the antioxidant is 1098.

[0060] Preferably, the mass ratio of the flame retardant monomer composition, the catalyst, the antioxidant and water is 1:0.001-0.01:0.002-0.01:3-6, more preferably 1:0.002-0.005:0.003-0.005:4-5.

[0061] Preferably, the salt-forming reaction temperature is 40-80° C., more preferably 55-70° C.; the salt-forming reaction time is 0.5-2 h, more preferably 1-1.5 h.

[0062] Preferably, the prepolymerization temperature is 160-220° C., more preferably 180-200° C.; the prepolymerization time is 1-3 h, more preferably 1.5-2 h; and the prepolymerization pressure is 1.0-2.0 MPa, more preferably 1.3-1.5 MPa.

[0063] 2.2 High temperature polyamide

[0064] Except for the -NH2 and -COOH at both ends of the prepolymer, the general description of the high-temperature polyamide is the same as that of the aforementioned high-temperature polyamide segment section and will not be repeated here.

[0065] In some embodiments, the method for preparing high temperature polyamide comprises the following steps:

[0066] (1) subjecting the high-temperature polyamide monomer composition to a salt-forming reaction to obtain a high-temperature polyamide salt;

[0067] (2) heating the high-temperature polyamide salt to perform a prepolymerization reaction to obtain a high-temperature polyamide prepolymer;

[0068] (3) The high-temperature polyamide salt prepolymer continues to heat up to undergo a condensation reaction.

[0069] In some embodiments, the high temperature polyamide monomer in the high temperature polyamide monomer composition in step (1) comprises a mixture of a dibasic acid and a diamine or a mixture of a dibasic acid, a diamine and a lactam; wherein the dibasic acid comprises at least one aromatic dibasic acid and optionally at least one aliphatic dibasic acid.

[0070] In some embodiments, aromatic dibasic acids include but are not limited to terephthalic acid, isophthalic acid, 2-methylterephthalic acid, 2,5-dimethylterephthalic acid, 5-methylisophthalic acid, etc.; aliphatic dibasic acids include but are not limited to 1,4-butanedioic acid, 1,5-pentanedioic acid, 1,6-hexanedioic acid, 1,7-pimelic acid, 1,8-octanedioic acid, 1,9-nonanedioic acid, 1,10-decanedioic acid, 1,11-undecanedioic acid, 1,12-dodecanedioic acid, etc.

[0071] In some embodiments, the molar ratio of the aromatic dibasic acid to the aliphatic dibasic acid is between 35 / 65 and 99 / 1, preferably within the range of 40 / 60 to 95 / 5.

[0072] In some embodiments, the diamine includes but is not limited to 1,4-butanediamine, 1,5-pentanediamine, 2-methyl-1,5-pentanediamine, 1,6-hexanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, p-phenylenediamine, m-phenylenediamine, and the like.

[0073] In some embodiments, lactams include butyrolactam, caprolactam, laurolactam, and the like.

[0074] In some embodiments, the molar ratio of diamine to dibasic acid in the high-temperature polyamide monomer composition is between 1-1.1, preferably 1.01-1.08. Since diamine has a low boiling point and is easily lost with the discharge of water during the reaction, diamine is often excessive during the prepolymerization reaction to compensate for the loss of diamine.

[0075] Preferably, the mass proportion of lactam in the high-temperature polyamide monomer composition is 0-80%, preferably 20-70%, more preferably 30-60%.

[0076] The high-temperature polyamide monomer composition generally further comprises a catalyst and an antioxidant, but does not contain an end-capping agent. The catalyst and antioxidant are not particularly limited, and any additive known in the art for acid and amine condensation reactions can be used.

[0077] For example, the catalyst can be selected from one or a combination of sodium phosphate, magnesium phosphate, calcium phosphate, magnesium phosphite, calcium phosphite, zinc phosphite, and sodium hypophosphite. Preferably, the catalyst is sodium hypophosphite.

[0078] For example, the antioxidant can be selected from one or a combination of 1098, 168, 1010, 1076, copper salt, and preferably, the antioxidant is a combination of 1098 and 168.

[0079] In some embodiments, the mass ratio of the high temperature polyamide monomer, catalyst, antioxidant and water in the high temperature polyamide monomer composition is 1:0.001-0.01:0.002-0.01:0.3-0.6, preferably 1:0.002-0.005:0.003-0.006:0.4-0.5.

[0080] In some embodiments, the salt-forming reaction temperature in step (1) is 40-100° C., preferably 55-70° C., the salt-forming reaction time is 1-2 h, preferably 1-1.5 h, and the salt-forming reaction pressure is 0.1-0.3 MPa, preferably 0.1-0.2 MPa.

[0081] In some embodiments, the prepolymerization reaction temperature in step (2) is 180-250° C., preferably 190-230° C., the prepolymerization reaction time is 1-4 h, preferably 2-3 h, and the prepolymerization reaction pressure is 1.2-2.5 MPa, preferably 1.4-2.0 MPa.

[0082] In some embodiments, the polycondensation reaction temperature in step (3) is 290-330° C., preferably 295-320° C., the polycondensation reaction time is 1-4 h, preferably 2-3 h, and the polycondensation reaction pressure is 1.8-2.6 MPa, preferably 2.0-2.4 MPa.

[0083] 2.3 Copolymerization of high temperature polyamide and flame retardant prepolymer

[0084] In step (a2), the high temperature polyamide and the flame retardant prepolymer are copolymerized to obtain the intrinsic flame retardant high temperature polyamide copolymer of the present invention.

[0085] In some embodiments, the mass ratio of the flame retardant prepolymer to the high temperature polyamide is 5-25:100, preferably 10-20:100.

[0086] In some embodiments, the copolymerization temperature is 290-330° C., preferably 310-320° C.; the copolymerization time is 5-60 min, preferably 0.3-1.0 h; and the absolute pressure of the copolymerization vacuum is <1000 Pa, preferably <500 Pa.

[0087] In some embodiments, the method for preparing the intrinsically flame-retardant high-temperature polyamide comprises the following steps:

[0088] Step (b1) Preparation of flame retardant prepolymer

[0089] Add the flame retardant monomer composition, catalyst, antioxidant and water in a mass ratio of 1:0.001-0.01:0.002-0.01:3-6 into the polymerization kettle, and react at 40-80°C for 0.5-2h to form salt.

[0090] Then, the temperature is raised to 160-220°C, the pressure is controlled at 1.0-2.0 MPa, and the reaction is carried out for 1-3 hours to form a flame retardant prepolymer;

[0091] Step (b2) Preparation of high-temperature polyamide

[0092] The high-temperature polyamide monomer, catalyst, antioxidant and water are mixed in a mass ratio of 1:0.001-0.01:0.002-0.01:0.3-0.6, and then kept warm for 1-2 hours at a temperature of 40-100°C and a pressure of 0.1-0.3 MPa to perform a salt-forming reaction;

[0093] Then, the temperature is raised to 180-250°C, the pressure is controlled at 1.2-2.5 MPa, and the reaction is carried out for 1-4 hours for prepolymerization;

[0094] Continue to raise the temperature to 290-330°C, maintain the pressure in the autoclave at 1.8-2.6 MPa, and carry out polycondensation at constant pressure for 1-4 hours to obtain high-temperature polyamide;

[0095] Step (b3) final polymerization

[0096] Add the flame retardant prepolymer prepared in step (b1) to the high-temperature polyamide obtained in step (b2), with the mass ratio of the flame retardant prepolymer to the high-temperature polyamide being 5-25:100. Maintain the temperature at 290-330°C, evacuate for 5-60 minutes, control the vacuum degree at an absolute pressure of <1000Pa, observe until the current reaches the specified value, discharge, pelletize, and dry to obtain a halogen-free intrinsically flame-retardant high-temperature polyamide copolymer.

[0097] The intrinsic flame-retardant high-temperature polyamide copolymer prepared by the present invention has the advantages of good mechanical properties, stable thermal properties, and excellent flame-retardant properties, and can be applied to fields with high requirements for temperature resistance and flame-retardant properties.

[0098] Another aspect of the present invention relates to the use of the intrinsically flame-retardant high-temperature polyamide copolymer according to the present invention in the preparation of electrical and electronic components or in automotive materials.

[0099] Beneficial effects

[0100] (1) The present invention adopts a new type of high-efficiency reactive N-Si synergistic flame retardant, and adopts a copolymerization method to form a copolymer of the flame retardant prepolymer and the high-temperature polyamide. While meeting the flame retardancy, it significantly improves the anti-dripping property, so that the flame retardancy reaches the UL94V0 level, and the mechanical properties of the high-temperature polyamide, especially the toughness, do not change significantly.

[0101] (2) The present invention adopts a method of prepolymerizing the flame retardant composition salt and then copolymerizing it with high-temperature polyamide, which avoids the disadvantage of high-temperature polyamide reaction temperature, which leads to insufficient thermal stability of the flame retardant, and ensures the excellent flame retardant properties and mechanical properties of the intrinsic flame retardant high-temperature polyamide copolymer.

[0102] The present invention has been described in detail above, but the above embodiments are merely illustrative in nature and are not intended to limit the present invention. In addition, the present invention is not limited by any theory described in the above prior art or invention summary or the following examples.

[0103] Unless otherwise expressly stated, the numerical ranges throughout the application include any subranges therein and any numerical values incremented by the smallest subunit of a given value therein. Unless otherwise expressly stated, the numerical values throughout the application represent approximate measurements or limitations of the range of embodiments including slight deviations from the given values and having approximately the values mentioned as well as having the exact values mentioned. Except for the working examples provided at the end of the detailed description, all numerical values of the parameters (e.g., quantities or conditions) in this application (including the appended claims) should be understood in all cases to be modified by the term "approximately", regardless of whether "approximately" actually appears before the numerical value. "Approximately" means that the numerical value described allows for slight imprecision (there is some close accuracy in the value; approximately or reasonably close to the value; approximately). If the imprecision provided by "approximately" is not understood in this art with this common meaning, then the "approximately" used herein at least represents the variation that can be produced by ordinary methods of measuring and using these parameters. For example, “about” can include a variation of less than or equal to 10%, less than or equal to 5%, less than or equal to 4%, less than or equal to 3%, less than or equal to 2%, less than or equal to 1%, or less than or equal to 0.5%, and in some aspects, a variation of less than or equal to 0.1%. DETAILED DESCRIPTION

[0104] The present invention will be further described below with reference to the examples. It should be noted that the following examples are provided for illustrative purposes only and do not constitute a limitation on the scope of protection claimed in the present invention.

[0105] Unless otherwise specified, the raw materials, reagents, methods, etc. used in the examples are conventional raw materials, reagents, and methods in the art.

[0106] Preparation Example 1 Preparation of flame retardant compound 1

[0107]

[0108] In a 1000 mL round-bottom flask, add a stirring magnet, a thermometer, and a reflux condenser. 92 g (0.50 mol) of cyanuric chloride and 100 mL of anhydrous acetonitrile were added to a round-bottom flask, and 150 g (1.5 mol) of anhydrous triethylamine was added as an acid binding agent. The mixture was stirred thoroughly and the temperature of the system was lowered to -5°C. Subsequently, 0.50 mol of an acetonitrile solution of p-hydroxybenzoic acid (100 mL) was slowly added dropwise. After the addition was complete, the temperature of the system was gradually raised to 60°C, and the reaction was continued with stirring for 4-6 hours. Subsequently, 0.50 mol of p-hydroxybenzoic acid was added to the system, and the temperature was maintained and stirred for 2-3 hours. Finally, 100 mL of concentrated aqueous ammonia was slowly added dropwise to the system to stop the reaction. Most of the organic solvent was distilled off under reduced pressure, and 1.0 mol / L dilute hydrochloric acid was subsequently added to the system to adjust the aqueous phase to a pH of 3.0 or less. The mixture was filtered, and the filter cake was washed with saturated brine and deionized water. The crude product was recrystallized from ethyl acetate-petroleum ether to obtain 113 g of a light yellow solid powder (i.e., compound 1) in a yield of 49.1%. 1 H-NMR(400MHz,DMSO-d6,D2O)δ(ppm):7.88(d,4H),7.03(d,4H); MS:m / z391.28([M+Na] + ).

[0109] Example 1

[0110] Step (1) Preparation of flame retardant prepolymer

[0111] 1000 g, 5 g, 10 g, and 4000 g of a flame retardant monomer composition, sodium hypophosphite, antioxidant 1098, and water, respectively, were added to a 10 L polymerization kettle, wherein the flame retardant monomer composition was a composition consisting of compound 1, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, and hexamethylenediamine in a molar ratio of 2:1:1. The polymerization kettle was filled with nitrogen to 0.1 MPa, and then vacuumed for 3 times to exhaust the air in the kettle. The temperature was then raised to 50° C. and reacted for 1 hour. The temperature was further raised to 190-200° C., the pressure was controlled at 1.2-1.5 MPa, and the reaction was carried out for 1.5 hours to form a flame retardant prepolymer.

[0112] Step (2) Preparation of high temperature polyamide

[0113] A high-temperature polyamide monomer, sodium hypophosphite, an antioxidant 1098 and water (2000 g, 10 g, 20 g and 1000 g, respectively) are mixed and added into a 5-L polymerization kettle, wherein the high-temperature polyamide monomer is a composition of terephthalic acid, hexamethylenediamine and caprolactam in a molar ratio of 1:1.02:0.90. The polymerization kettle is filled with nitrogen to 0.1 MPa, and then vacuumed three times to exhaust the air in the kettle. The kettle is then kept warm at 50° C. for 1 hour to perform a salt-forming reaction. The temperature is then raised to 200° C., the pressure is controlled at 1.5 MPa, and the reaction is performed for 2 hours to perform prepolymerization. The temperature is further raised to 310-320° C., the pressure in the kettle is maintained at 2.0-2.4 MPa by exhausting the steam in the kettle, the kettle is reacted at constant pressure for 2 hours to perform condensation, and the pressure is continuously released to normal pressure to obtain a high-temperature polyamide.

[0114] Step (3) Preparation of intrinsic flame-retardant high-temperature polyamide copolymer

[0115] Add 400 g of the flame retardant prepolymer prepared in step (1) to the high-temperature polyamide obtained in step (2), maintain the temperature at 310-320°C, evacuate for 30 minutes, control the vacuum degree at an absolute pressure of <500 Pa, observe the current to reach the specified value, discharge, pelletize, and dry to obtain a nylon copolymer.

[0116] Example 2

[0117] The difference between this embodiment and embodiment 1 is that the vacuuming time in step (3) is 10 minutes, and the rest is the same as embodiment 1.

[0118] Comparative Example 1

[0119] High temperature polyamide preparation

[0120] A high-temperature polyamide monomer, sodium hypophosphite, an antioxidant 1098 and water are mixed in amounts of 1000 g, 5 g, 10 g and 500 g respectively, wherein the high-temperature polyamide monomer is a composition of terephthalic acid, hexamethylenediamine and adipic acid in a molar ratio of 0.5:1.02:0.5. The mixture is kept at 50° C. for 1 hour for salt-forming reaction. The mixture is then heated to 200° C., the pressure is controlled at 1.5 MPa, and the mixture is reacted for 2 hours for prepolymerization. The mixture is further heated to 310-320° C., the pressure in the kettle is maintained at 2.0-2.4 MPa by discharging steam in the kettle, the mixture is reacted at constant pressure for 2 hours for condensation, and the pressure is continuously released to normal pressure to obtain the high-temperature polyamide.

[0121] Comparative Example 2

[0122] The difference between this comparative example and Example 1 is that the flame retardant monomer composition is a composition consisting of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and adipic acid in a molar ratio of 1:1, and the rest is the same as Example 1.

[0123] Comparative Example 3

[0124] Preparation of flame retardant high temperature polyamide

[0125] High-temperature polyamide monomer, flame retardant monomer composition, sodium hypophosphite, antioxidant 1098 and water are mixed in a mass of 2000g, 430g, 12.15g, 24.3g and 3150g respectively, wherein the high-temperature polyamide monomer is a composition of terephthalic acid, hexamethylenediamine and caprolactam in a molar ratio of 1:1.02:0.90, and the mixture is kept at a temperature of 50°C for 1-2h to perform salt formation reaction; then the temperature is raised to 200°C and the pressure is controlled. The prepolymerization is carried out at 1.5 MPa for 2 hours; the temperature is continuously raised to 310-320°C, the pressure in the autoclave is maintained at 2.0-2.4 MPa by discharging the steam in the autoclave, the polycondensation is carried out at constant pressure for 2 hours, and then the pressure is continuously released to normal pressure; for the final polymerization, the temperature is maintained at 310-320°C, vacuuming is carried out for 15 minutes, the vacuum degree is controlled at an absolute pressure of less than 500 Pa, the current is observed to reach a specified value, the material is discharged, pelletized, and dried to obtain an intrinsically flame-retardant high-temperature nylon copolymer.

[0126] Experimental example

[0127] The performance tests of the polyamide resins of the examples and comparative examples were performed, and the results are shown in the following table.

[0128] Test method:

[0129] Vertical combustion (UL-94) test: refer to GB / T8333-2008 "Test method for combustion performance of rigid foam plastics - Vertical combustion method".

[0130] Limiting Oxygen Index (LOI) testing: Tested at room temperature using an HC-2CZ LOI tester, in accordance with GB / T 2406.2-2009, "Plastics - Determination of Combustion Behavior by Oxygen Index Method." Sample size: 130 mm × 6.5 mm × 3.0 mm. Top-side ignition method used.

[0131] Tensile strength: Refer to ISO572-1 / -2.

[0132] Impact strength: Refer to ISO11357.

[0133] Melting point: Refer to JBT8630-1997 "Test method for heat of fusion, melting point, heat of crystallization and crystallization temperature of electrical insulating materials by differential scanning calorimetry".

[0134]

[0135] From the data in the table, it can be seen that when no flame retardant or compound 1 is added, the flame retardancy level of the high-temperature polyamide is V2, while the flame retardancy level of the intrinsic flame-retardant polyamide copolymers to which the flame retardant compound 1 and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane are added reaches V0. At the same time, in the embodiment where compound 1 and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane are added, the mechanical properties of the product copolymerized in the form of a flame retardant prepolymer and a high-temperature polyamide prepolymer are significantly higher than those of the product directly copolymerized in the form of a monomer, and there is no significant difference in mechanical properties from the high-temperature polyamide to which no flame retardant is added. The mechanical properties of the product with a short negative pressure polymerization time are slightly worse, indicating that the preparation method of the present invention can prepare an intrinsic flame-retardant high-temperature nylon copolymer with excellent mechanical properties.

[0136] The above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced with equivalents, without departing from the spirit and substance of the claims of the present invention; and such modifications or replacements remain within the scope of the claims of the present invention.

Claims

1. An intrinsically flame-retardant high-temperature polyamide copolymer, wherein the intrinsically flame-retardant high-temperature polyamide copolymer is represented by the following structural formula: -[A-B] n - in, A represents a high-temperature polyamide segment; B represents a flame retardant prepolymer segment; n represents the number of polymer segments, The high temperature polyamide segment is represented by the following structural formula: or wherein the P1 unit is derived from at least one aromatic dibasic acid, and optionally at least one aliphatic dibasic acid; The P2 unit is derived from at least one aromatic diamine, or at least one aliphatic diamine; The L unit is derived from a lactam; n1 represents the degree of polymerization; The weight average molecular weight of the high temperature polyamide segment is 10,000-40,000; The molar ratio of P1 unit to P2 unit is 1:1-1.1; or The molar ratio of P1 unit, P2 unit and L unit is 1:1-1.1:0.8-1.1; The flame retardant prepolymer segment is used Indicates, or The flame retardant prepolymer segment is obtained by polymerizing monomers corresponding to the A1 unit, the D1 unit and the F1 unit, wherein the molar ratio of the A1 unit, the D1 unit and the F1 unit is 2:1-1.1:0.8-1.1; The A1 unit is derived from the structure shown in formula (1): （1） wherein R1 and R2 are each independently selected from -O- or -NH-; Unit D1 is derived from: ; The F1 unit is derived from: a diamine having 2 to 12 carbon atoms; n2 represents the degree of polymerization; The weight average molecular weight of the flame retardant prepolymer chain segment is 10,000-30,000; The mass ratio of the high temperature polyamide chain segment to the flame retardant prepolymer chain segment is 19:1-3:

1.

2. The intrinsic flame retardant high temperature polyamide copolymer according to claim 1, wherein The weight average molecular weight of the high temperature polyamide segment is 25,000-35,000.

3. The intrinsic flame retardant high temperature polyamide copolymer according to claim 1, wherein The molar ratio of P1 unit to P2 unit is 1:1.01-1.08; or The molar ratio of the P1 unit, the P2 unit and the L unit is 1:1.01-1.08:0.8-1.

0.

4. The intrinsic flame retardant high temperature polyamide copolymer according to claim 1, wherein The weight average molecular weight of the flame retardant prepolymer chain segment is 15,000-20,000.

5. The intrinsic flame retardant high temperature polyamide copolymer according to claim 1, wherein The flame retardant prepolymer chain segment is obtained by polymerizing monomers corresponding to the A1 unit, the D1 unit and the F1 unit, and the molar ratio of the A1 unit, the D1 unit and the F1 unit is 2:1:

1.

6. The intrinsic flame retardant high temperature polyamide copolymer according to claim 1, wherein The mass ratio of the high temperature polyamide chain segment to the flame retardant prepolymer chain segment is 9:1-4:

1.

7. The method for preparing the intrinsic flame retardant high temperature polyamide copolymer according to any one of claims 1 to 6, comprising the following steps: (a1) providing a high-temperature polyamide and a flame retardant prepolymer, wherein the mass ratio of the flame retardant prepolymer to the high-temperature polyamide is 5-25:100; (a2) copolymerizing the high-temperature polyamide and the flame retardant prepolymer to obtain an intrinsically flame-retardant high-temperature polyamide copolymer; The flame retardant prepolymer is prepared by a method comprising the following steps: adding a flame retardant monomer composition, a catalyst, an antioxidant and water into a polymerization kettle for salt formation reaction to obtain a flame retardant salt; heating the flame retardant salt for prepolymerization reaction to obtain a flame retardant prepolymer; The flame retardant monomer composition includes a diamine and a dibasic acid, the diamine includes 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and optionally other diamines, and the dibasic acid includes flame retardant A; The molar ratio of the dibasic acid to the diamine in the flame retardant monomer composition is 1:1.001-1.1; the molar ratio of the flame retardant A in the flame retardant monomer composition is not less than 50%, and the molar ratio of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane in the flame retardant monomer composition is not less than 20%; The flame retardant A has a structure as shown in formula (1): （1） wherein R1 and R2 are each independently selected from -O- or -NH-.

8. The preparation method according to claim 7, wherein The molar ratio of the dibasic acid to the diamine in the flame retardant monomer composition is 1:1.005-1.

05.

9. The preparation method according to claim 7, wherein Flame retardant A is selected from one or more of the following compounds: 。 10. The preparation method according to claim 7, wherein The mass ratio of the flame retardant monomer composition, the catalyst, the antioxidant and water is 1:0.001-0.01:0.002-0.01:3-6.

11. The preparation method according to claim 7, wherein The mass ratio of the flame retardant monomer composition, the catalyst, the antioxidant and water is 1:0.002-0.005:0.003-0.005:4-5.

12. The preparation method according to claim 7, wherein The salt-forming reaction temperature is 40-80° C.; the salt-forming reaction time is 0.5-2 h.

13. The preparation method according to claim 7, wherein The salt-forming reaction temperature is 40-80° C.; the salt-forming reaction time is 1-1.5 h.

14. The preparation method according to claim 7, wherein The prepolymerization reaction temperature is 160-220° C.; the prepolymerization reaction time is 1-3 hours; and the prepolymerization reaction pressure is 1.0-2.0 MPa.

15. The preparation method according to claim 7, wherein The prepolymerization reaction temperature is 180-200° C.; the prepolymerization reaction time is 1.5-2 hours; and the prepolymerization reaction pressure is 1.3-1.5 MPa.

16. The preparation method according to claim 7, wherein The preparation method of high temperature polyamide comprises the following steps: (1) subjecting a high-temperature polyamide monomer, a catalyst, an antioxidant and water to a salt-forming reaction to obtain a high-temperature polyamide salt; the high-temperature polyamide monomer comprises a mixture of a dibasic acid and a diamine, or a mixture of a dibasic acid, a diamine and a lactam; wherein the dibasic acid comprises at least one aromatic dibasic acid and, optionally, at least one aliphatic dibasic acid; (2) The high-temperature polyamide salt is heated to perform a prepolymerization reaction to obtain a high-temperature polyamide prepolymer; (3) The high-temperature polyamide salt prepolymer continues to heat up to undergo a condensation reaction.

17. The preparation method according to claim 16, wherein The mass ratio of the high-temperature polyamide monomer, the catalyst, the antioxidant and water is 1:0.001-0.01:0.002-0.01:0.3-0.

6.

18. The preparation method according to claim 16, wherein The mass ratio of the high-temperature polyamide monomer, the catalyst, the antioxidant and water is 1:0.002-0.005:0.003-0.006:0.4-0.

5.

19. The preparation method according to claim 16, wherein In step (1), the salt-forming reaction temperature is 40-100° C., the salt-forming reaction time is 1-2 h, and the salt-forming reaction pressure is 0.1-0.3 MPa.

20. The preparation method according to claim 16, wherein In step (1), the salt-forming reaction temperature is 55-70° C., the salt-forming reaction time is 1-1.5 h, and the salt-forming reaction pressure is 0.1-0.2 MPa.

21. The preparation method according to claim 16, wherein In step (2), the prepolymerization temperature is 180-250° C., the prepolymerization time is 1-4 h, and the prepolymerization pressure is 1.2-2.5 MPa.

22. The preparation method according to claim 16, wherein In step (2), the prepolymerization temperature is 190-230° C., the prepolymerization time is 2-3 h, and the prepolymerization pressure is 1.4-2.0 MPa.

23. The preparation method according to claim 16, wherein In step (3), the polycondensation reaction temperature is 290-330° C., the polycondensation reaction time is 1-4 h, and the polycondensation reaction pressure is 1.8-2.6 MPa.

24. The preparation method according to claim 16, wherein In step (3), the polycondensation reaction temperature is 295-320° C., the polycondensation reaction time is 2-3 h, and the polycondensation reaction pressure is 2.0-2.4 MPa.

25. The preparation method according to claim 7, wherein The mass ratio of the flame retardant prepolymer to the high-temperature polyamide is 10-20:

100.

26. The preparation method according to claim 7, wherein The copolymerization temperature is 290-330° C.; the copolymerization time is 5-60 min; and the absolute pressure of the copolymerization vacuum is less than 1000 Pa.

27. The preparation method according to claim 7, wherein The copolymerization temperature is 310-320°C; the copolymerization time is 0.3-1.0h; and the absolute pressure of the copolymerization vacuum is less than 500Pa.

28. The preparation method according to claim 7, wherein The preparation method of the intrinsic flame-retardant high-temperature polyamide comprises the following steps: Step (b1) Preparation of flame retardant prepolymer Add the flame retardant monomer composition, catalyst, antioxidant and water in a mass ratio of 1:0.001-0.01:0.002-0.01:3-6 into the polymerization kettle, and react at 40-80°C for 0.5-2h to form salt. Then, the temperature is raised to 160-220°C, the pressure is controlled at 1.0-2.0 MPa, and the reaction is carried out for 1-3 hours to form a flame retardant prepolymer; Step (b2) Preparation of high-temperature polyamide The high-temperature polyamide monomer, catalyst, antioxidant and water are mixed in a mass ratio of 1:0.001-0.01:0.002-0.01:0.3-0.6, and then kept warm for 1-2 hours at a temperature of 40-100°C and a pressure of 0.1-0.3 MPa to perform a salt-forming reaction; Then, the temperature is raised to 180-250°C, the pressure is controlled at 1.2-2.5 MPa, and the reaction is carried out for 1-4 hours for prepolymerization; Continue to raise the temperature to 290-330°C, maintain the pressure in the autoclave at 1.8-2.6 MPa, and carry out polycondensation at constant pressure for 1-4 hours to obtain high-temperature polyamide; Step (b3) Final polymerization Add the flame retardant prepolymer prepared in step (b1) to the high-temperature polyamide obtained in step (b2), with the mass ratio of the flame retardant prepolymer to the high-temperature polyamide being 5-25:

100. Maintain the temperature at 290-330°C, evacuate for 5-60 minutes, control the vacuum degree at an absolute pressure of <1000 Pa, observe until the current reaches the specified value, discharge, pelletize, and dry to obtain a halogen-free intrinsically flame-retardant high-temperature polyamide copolymer.

29. Use of the intrinsically flame-retardant high-temperature polyamide copolymer according to any one of claims 1 to 6 in the preparation of electrical and electronic components or in automotive materials.

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