Antibacterial copolymerized polyamide and preparation method thereof

Abstract

The invention relates to antibacterial copolymerized polyamide and a preparation method thereof. The antibacterial copolymerized polyamide comprises a polyamide A structure formed by hexamethylenediamine and dodecanedioic acid, at least one polyamide B structure except the polyamide A, and an antibacterial agent C structure, the polyamide B structure is formed by at least one binary acid b1 and at least one diamine b2, and / or lactam b3 through ring opening; the structure of the antibacterial agent C contains a quaternary phosphonium salt group and is formed by a quaternary phosphonium salt antibacterial agent containing a carboxylic acid group and diamine b2; the melting point of the antibacterial copolymerized polyamide is 180 DEG C to 210 DEG C. The antibacterial copolymerized polyamide disclosed by the invention is good in antibacterial stability and has an efficient and lasting antibacterial effect, and the transparency of the polyamide is not influenced.

Description

Technical Field

[0001] The invention belongs to the technical field of polyamide resins, and particularly relates to an antibacterial polyamide and a preparation method thereof. Background Art

[0002] With the increasing living standards and health awareness, antibacterial nylon fabrics with "self-cleaning" functions are becoming more and more interesting. These types of antibacterial fibers or fabrics can be used in many industries, including healthcare, hospitality services, military and sports. However, conventional antibacterial fibers or fabrics are difficult to meet the requirements of these applications in actual use. In many applications, repeated use and washing cycles are quite common. Unfortunately, it has been found that conventional nylon fabrics will deteriorate during repeated use or washing cycles, and a large proportion of antibacterial properties will be lost, which ultimately causes the existing antibacterial nylon fibers to be unable to effectively meet the actual application needs of the market and form large-scale production.

[0003] Chinese patent CN106633829A discloses an antibacterial nylon with attapulgite-nanosilver composite inorganic powder as an antibacterial agent additive and a preparation method thereof. Although the antibacterial agent has the advantages of small amount of high efficiency, low price and simple process, it does not take into account the lack of long-term stability of silver nanoparticle antibacterial agents, and is prone to agglomeration and oxidative discoloration, which affects its long-term antibacterial activity. Chinese patent CN107541054A discloses an antibacterial nylon with a mixture of polyguanidine salt and sodium hydroxypyrithione as an antibacterial agent and a preparation method thereof, and the antibacterial nylon material is prepared by melt blending nylon with an antibacterial agent and a dispersant, and extruding and granulating. However, the polyguanidine salt in the added antibacterial agent has a large water solubility, which is easy to cause compatibility problems and yellowing phenomenon with nylon materials under long-term use, and may affect the mechanical properties and chemical stability of nylon materials. Patent CN113502660A discloses a method of preparing modified polyamide fiber by polymerizing alkyl biguanide salt and polyamide, and then spraying a finishing agent on the fiber; this technology is complicated to operate, the antibacterial component is unevenly distributed and the amount added is large, and post-finishing is required to ensure the antibacterial effect. Patent CN101942759A discloses a method of adding fiber to a solution containing silver nitrate to absorb the silver nitrate in the solution, and then reducing the adsorbed fiber to obtain an antibacterial fiber or fabric with silver attached to the surface. This method cannot form a uniform and stable antibacterial coating, the antibacterial time is limited, and it cannot achieve long-lasting antibacterial effect.

[0004] In summary, the main methods to achieve the antibacterial function of nylon fibers are through surface modification technology or blending modification technology. However, these two technologies cannot solve the compatibility problem with the nylon bulk material and the precipitation failure problem under long-term use conditions. Therefore, the technical research on efficient and durable reactive antibacterial agents and long-lasting antibacterial polyamides is crucial. Summary of the invention

[0005] Technical problem: To overcome the above technical defects, the purpose of the present invention is to disclose an antibacterial copolymer polyamide and its preparation. The antibacterial copolymer polyamide of the invention has good antibacterial stability, has a high-efficiency and long-lasting antibacterial effect, and does not affect the transparency of the polyamide itself.

[0006] Technical solution: An antibacterial copolymer polyamide of the present invention comprises a polyamide A structure formed by hexamethylenediamine and dodecanedioic acid, at least one polyamide B structure other than polyamide A, and an antibacterial agent C structure;

[0007] The polyamide B structure is formed by at least one dibasic acid b1 and at least one diamine b2, and / or by ring-opening of lactam b3;

[0008] The structure of the antibacterial agent C contains a quaternary phosphonium salt group, and is formed by a quaternary phosphonium salt antibacterial agent containing a carboxylic acid group and a diamine b2.

[0009] The mass ratio of the polyamide A structure to the antibacterial copolymer polyamide is 70% to 95%;

[0010] The mass ratio of the polyamide B structure to the antibacterial copolymer polyamide is 4% to 29%;

[0011] The mass ratio of the antibacterial agent C structure to the antibacterial copolymer polyamide is 0.2% to 1%;

[0012] The melting point of the antibacterial copolymer polyamide is 180°C to 210°C.

[0013] The dibasic acid b1 includes aromatic dibasic acids, preferably, at least one of terephthalic acid, terephthalic acid, terephthalic acid, isophthalic acid, isophthalic acid, phthalic acid, and phthalic acid.

[0014] The diamine b2 independently includes C2-C14 diamines, preferably, one or more of pentamethylenediamine, hexamethylenediamine, octanediamine, decanediamine, and 1,12-diaminododecane.

[0015] The lactam b3 includes at least one of butyrolactam, valerolactam, caprolactam, capryllactam, lauryl lactam, N-methyl caprolactam, N-vinyl caprolactam and 4-tert-butyl caprolactam.

[0016] The quaternary phosphonium salt antibacterial agent containing a carboxylic acid group includes tributyl carboxymethyl phosphonium chloride and / or 2-(carboxyethyl) triphenyl phosphonium bromide.

[0017] A method for preparing an antibacterial copolymer polyamide of the present invention is:

[0018] In the presence of protective gas, a solution containing polyamide A salt, a solution containing polyamide B salt and / or lactam b3 and a solution containing antibacterial agent C salt are mixed to form a mixed solution, and the mixed solution is polymerized to form an antibacterial copolymer polyamide.

[0019] The solution containing polyamide A salt is prepared by dissolving hexamethylenediamine and dodecanedioic acid in a solvent to form a salt solution;

[0020] The solution containing the polyamide B salt is prepared by dissolving at least one dibasic acid b1, at least one diamine b2 and / or lactam b3 in a solvent to form a salt solution.

[0021] The antibacterial agent C salt solution is prepared by dissolving a quaternary phosphonium salt antibacterial agent containing a carboxylic acid group and a diamine b2 in a solvent to form a salt solution.

[0022] The protective gas includes one or more of nitrogen, carbon dioxide, argon and helium, and does not participate in the polymerization reaction; the polymerization temperature is 150° C. to 280° C., and the pressure is 0 to 2.0 MPa.

[0023] The solvent includes water.

[0024] The temperatures of the polyamide A salt solution, the polyamide B salt solution and the antibacterial agent C salt solution are respectively controlled at 50° C. to 80° C., and their mass percentages are respectively controlled at 20 to 60%.

[0025] Beneficial effects: Compared with polyamides using conventional additive antibacterial agents or metal ion antibacterial agents, the antibacterial copolymer polyamide of the present invention has good antibacterial stability, has a high-efficiency and lasting antibacterial effect, and does not affect the transparency of the polyamide itself. The specific quaternary phosphonium salt antibacterial agent C used as one of the structures of the polyamide not only plays an antibacterial role but also has a certain catalytic and end-capping effect, and can regulate the molecular weight of the polyamide; combined with the introduction of the polyamide B structure, it plays a role in destroying the regularity of the polyamide A to a certain extent, and on the basis of ensuring that the main polyamide A structure still has a relatively complete regularity, it effectively slows down the crystallinity of the polyamide A structure, and further enables the antibacterial effect to be effectively exerted. DETAILED DESCRIPTION

[0026] The antibacterial copolymer polyamide of the present invention comprises a polyamide A structure formed by hexamethylenediamine and dodecanedioic acid, at least one polyamide B structure other than polyamide A, and an antibacterial agent C structure;

[0027] The polyamide B structure is formed by at least one dibasic acid b1 and at least one diamine b2, and / or by ring-opening of lactam b3;

[0028] The diamine b1 includes C2-C14 diamines, preferably, one or more of pentamethylenediamine, hexamethylenediamine, octanediamine, decanediamine, and 1,12-diaminododecane;

[0029] The dibasic acid b2 includes aromatic dibasic acids, preferably, at least one of terephthalic acid, terephthalic acid, terephthalic acid, isophthalic acid, isophthalic acid, phthalic acid, and phthalic acid;

[0030] The lactam b3 includes at least one of butyrolactam, valerolactam, caprolactam, capryllactam, lauryl lactam, N-methyl caprolactam, N-vinyl caprolactam and 4-tert-butyl caprolactam;

[0031] The antibacterial agent C structure contains a quaternary phosphonium salt group, and is formed by a quaternary phosphonium salt antibacterial agent containing a carboxylic acid group and a diamine b2;

[0032] The carboxylic acid group-containing quaternary phosphonium salt antibacterial agent includes tributyl carboxylmethyl phosphonium chloride and / or 2-(carboxyethyl)triphenyl phosphonium bromide;

[0033] The diamine b2 includes C2-C14 diamines, preferably, one or more of pentamethylenediamine, hexamethylenediamine, octanediamine, decanediamine, and 1,12-diaminododecane;

[0034] The melting point (Tm) of the antibacterial polyamide is 180°C to 210°C, preferably 195°C to 205°C;

[0035] In the present invention, the polyamide B structure mainly plays a role in destroying the regularity of the polyamide A structure to a certain extent. On the basis of ensuring that the polyamide A structure still has a relatively complete regularity, it effectively slows down the crystallinity of the polyamide A structure, which is reflected in a slight decrease in the melting point and an increase in transparency on a macro scale.

[0036] The mass ratio of the polyamide A structure to the antibacterial copolymer polyamide is 70% to 95%;

[0037] The mass ratio of the polyamide B structure to the antibacterial copolymer polyamide is 4% to 29%;

[0038] The mass ratio of the antibacterial agent C structure to the antibacterial copolymer polyamide is 0.2% to 1%.

[0039] The invention discloses a method for preparing an antibacterial copolymer polyamide, comprising mixing a solution containing a polyamide A salt, a solution containing a polyamide B salt and / or a lactam b3, and a solution containing an antibacterial agent C salt to form a mixed solution, and polymerizing the mixed solution to form an antibacterial copolymer polyamide;

[0040] The preparation method is carried out in the presence of protective gas, the polymerization temperature is 150°C to 280°C, and the pressure is 0 to 2.0 MPa;

[0041] Preferably, the solvent can be removed by evaporation and concentration;

[0042] In some embodiments of the present invention, the method for preparing the antibacterial copolymer polyamide specifically comprises the following steps:

[0043] In the presence of a protective gas, a solution containing a polyamide A salt and a solution containing a polyamide B salt and / or a lactam b3 are mixed, and then polymerized and evaporated and concentrated to a mass percentage of 70% to 80% at a temperature of 120° C. to 160° C. and a pressure of 0.2 to 0.3 MPa;

[0044] Add a solution containing an antibacterial agent C salt and continue mixing, continue to fully polymerize at a temperature of 160° C. to 180° C. and a pressure of 1.5 to 2.0 MPa, and finally reduce the pressure to room temperature to obtain an antibacterial copolymer polyamide;

[0045] Preferably, the protective gas does not participate in the polymerization reaction and includes one or more of nitrogen, carbon dioxide, argon and helium;

[0046] In some embodiments of the present invention, the protective gas is nitrogen;

[0047] Further, the solution containing the polyamide A salt is prepared by dissolving hexamethylenediamine and dodecanedioic acid in a solvent to form a salt solution;

[0048] The solution containing the polyamide B salt is prepared by dissolving at least one dibasic acid b1 and at least one diamine b2 in a solvent to form a salt solution;

[0049] In some embodiments of the present invention, the polyamide B salt includes one or more of hexamethylenediamine terephthalate, hexamethylenediamine terephthalate, hexamethylenediamine terephthalate, and isophthalic acid pentamethylenediamine salt;

[0050] The solution containing lactam b3 is obtained by dissolving lactam b3 in a solvent;

[0051] In some examples of the present invention, the lactam b3 includes one or more of caprolactam, N-methyl caprolactam, N-vinyl caprolactam, 4-tert-butyl caprolactam, and lauryl lactam;

[0052] The solution containing the antibacterial agent C salt is prepared by dissolving a quaternary phosphonium salt antibacterial agent containing a carboxylic acid group and a diamine b2 in a solvent to form a salt solution;

[0053] The solvent includes water, and further, the water is desalinated;

[0054] In some examples of the present invention, the mass ratio of the polyamide A salt, the polyamide B salt and / or the lactam b3, and the antimicrobial agent C salt is 71-94: 5-28.5: 0.2-1.5;

[0055] The temperatures of the polyamide A salt solution, the polyamide B salt and / or lactam b3 solution, and the antibacterial C salt solution are controlled at 50°C to 80°C, and the mass percentages are controlled at 20 to 60% respectively.

[0056] In some examples of the present invention, the temperature of the polyamide A salt solution is controlled at 50°C to 80°C, and the mass percentage is controlled at 50-60%; the temperature of the solution containing polyamide B salt and / or lactam b3 is controlled at 50°C to 80°C, and the mass percentage is controlled at 50-60%; the temperature of the antibacterial agent C salt solution is controlled at 50°C to 80°C, and the mass percentage is controlled at 20-30%;

[0057] Preferably, the polymerization reaction can be accelerated in the presence of a catalyst in the above steps, and the catalyst includes one or more of sodium hypophosphite, sodium phosphite, and potassium hypophosphite;

[0058] Preferably, additives known in the art may be added, including antioxidants, light and heat stabilizers, end group regulators, flame retardants, and high temperature resistant additives;

[0059] The antioxidant is selected from hindered phenols, thioesters, phosphites and aromatic amine antioxidants;

[0060] The light and heat stabilizer is selected from hindered amine, benzotriazole or benzophenone light and heat stabilizers;

[0061] The end group regulator is selected from one or more of n-butylamine, n-pentylamine, n-hexylamine, benzylamine, phenylethylamine, acetic acid, propionic acid, butyric acid, benzoic acid, and phenylacetic acid;

[0062] The heat-resistant agent is selected from organic copper, inorganic copper salt and aromatic amine high temperature resistant additives;

[0063] The flame retardant is selected from organic phosphorus, organic aluminum and melamine flame retardants.

[0064] The principles and features of the present invention are described below in conjunction with implementation examples. The examples are provided to facilitate those skilled in the art to better understand the present invention. In addition, it should be understood that after reading the contents of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

[0065] Example 1

[0066] Antibacterial copolymer polyamide 1, comprising 84% by weight of a polyamide A structure, 15.5% by weight of a polyamide B structure, and 0.5% by weight of an antibacterial agent C structure;

[0067] Wherein, the polyamide A structure is formed by hexamethylenediamine and dodecanedioic acid;

[0068] The polyamide B structure is formed by ring opening of caprolactam;

[0069] The structure of antimicrobial agent C is formed by tributyl carboxymethyl phosphonium chloride containing a carboxylic acid group and hexamethylenediamine.

[0070] Example 2

[0071] Antimicrobial copolymer polyamide 2, comprising 75% by weight of a polyamide A structure, 24.7% by weight of a polyamide B structure, and 0.3% by weight of an antimicrobial agent C structure;

[0072] Wherein, the polyamide A structure is formed by hexamethylenediamine and dodecanedioic acid;

[0073] The polyamide B structure is formed from hexamethylenediamine and terephthalic acid;

[0074] The structure of antimicrobial agent C is formed by tributyl carboxymethyl phosphonium chloride containing a carboxylic acid group and hexamethylenediamine.

[0075] Example 3

[0076] Antimicrobial copolymer polyamide 3, comprising 86.2% by weight of a polyamide A structure, 13% by weight of a polyamide B structure, and 0.8% by weight of an antimicrobial agent C structure;

[0077] Wherein, the polyamide A structure is formed by hexamethylenediamine and dodecanedioic acid;

[0078] The polyamide B structure is formed by hexamethylenediamine and isophthalic acid;

[0079] The structure of antimicrobial agent C is formed by 2-(carboxyethyl)triphenylphosphonium bromide containing a carboxylic acid group and 1,12-diaminododecane.

[0080] Example 4

[0081] Antimicrobial copolymer polyamide 4, comprising 90% by weight of a polyamide A structure, 9% by weight of a polyamide B structure, and 1% by weight of an antimicrobial agent C structure;

[0082] Among them, the polyamide A structure is formed by the ring opening of caprolactam;

[0083] The polyamide B structure is formed by hexamethylenediamine and isophthalic acid;

[0084] The structure of antimicrobial agent C is formed by 2-(carboxyethyl)triphenylphosphonium bromide containing a carboxylic acid group and hexamethylenediamine.

[0085] Example 5

[0086] Antimicrobial copolymer polyamide 5, comprising 72.5% by weight of a polyamide A structure, 27% by weight of a polyamide B structure, and 0.5% by weight of an antimicrobial agent C structure;

[0087] Among them, the polyamide A structure is formed by the ring opening of caprolactam;

[0088] The polyamide B structure is formed from hexamethylenediamine and terephthalic acid;

[0089] The structure of antimicrobial agent C is formed by tributyl carboxymethyl phosphonium chloride containing a carboxylic acid group and hexamethylenediamine.

[0090] Example 6

[0091] Antimicrobial copolymer polyamide 6, comprising 75% by weight of a polyamide A structure, 24.7% by weight of a polyamide B structure, and 0.3% by weight of an antimicrobial agent C structure;

[0092] Wherein, the polyamide A structure is formed by hexamethylenediamine and dodecanedioic acid;

[0093] The polyamide B structure is formed by hexamethylenediamine and adipic acid;

[0094] The structure of antimicrobial agent C is formed by tributyl carboxymethyl phosphonium chloride containing a carboxylic acid group and hexamethylenediamine.

[0095] Example 7

[0096] Antimicrobial copolymer polyamide 7, comprising 84% by weight of a polyamide A structure, 15.5% by weight of a polyamide B structure, and 0.5% by weight of an antimicrobial agent C structure;

[0097] Wherein, the polyamide A structure is formed by hexamethylenediamine and dodecanedioic acid;

[0098] The polyamide B structure is formed by ring opening of caprolactam;

[0099] The structure of antimicrobial agent C is directly formed by dodecyl dimethyl phenoxyethyl ammonium bromide.

[0100] Example 8

[0101] Antimicrobial copolymer polyamide 8, comprising 84% by weight of a polyamide A structure, 15.5% by weight of a polyamide B structure, and 0.5% by weight of an antimicrobial agent C structure;

[0102] Wherein, the polyamide A structure is formed by hexamethylenediamine and dodecanedioic acid;

[0103] The polyamide B structure is formed by ring opening of caprolactam;

[0104] The antimicrobial agent C structure is formed directly by tributyl carboxymethyl phosphonium chloride.

[0105] Example 9

[0106] Antimicrobial copolymer polyamide 9, comprising 94% by weight of a polyamide A structure, 5% by weight of a polyamide B structure, and 1% by weight of an antimicrobial agent C structure;

[0107] Among them, the polyamide A structure is formed by the ring opening of caprolactam;

[0108] The polyamide B structure is formed by hexamethylenediamine and isophthalic acid;

[0109] The structure of antimicrobial agent C is formed by 2-(carboxyethyl)triphenylphosphonium bromide containing a carboxylic acid group and hexamethylenediamine.

[0110] Example 10

[0111] Antimicrobial copolymer polyamide 10, comprising 71% by weight of a polyamide A structure, 28.5% by weight of a polyamide B structure, and 0.5% by weight of an antimicrobial agent C structure;

[0112] Among them, the polyamide A structure is formed by the ring opening of caprolactam;

[0113] The polyamide B structure is formed from hexamethylenediamine and terephthalic acid;

[0114] The structure of antimicrobial agent C is formed by tributyl carboxymethyl phosphonium chloride containing a carboxylic acid group and hexamethylenediamine.

[0115] Embodiment 11

[0116] Antibacterial copolymer polyamide 11, comprising 75.2% by weight of a polyamide A structure, 24.7% by weight of a polyamide B structure, and 0.1% by weight of an antibacterial agent C structure;

[0117] Wherein, the polyamide A structure is formed by hexamethylenediamine and dodecanedioic acid;

[0118] The polyamide B structure is formed from hexamethylenediamine and terephthalic acid;

[0119] The structure of antimicrobial agent C is formed by tributyl carboxymethyl phosphonium chloride containing a carboxylic acid group and hexamethylenediamine.

[0120] Example 12

[0121] Antimicrobial copolymer polyamide 12, comprising 88.5% by weight of a polyamide A structure, 9% by weight of a polyamide B structure, and 1.5% by weight of an antimicrobial agent C structure;

[0122] Among them, the polyamide A structure is formed by the ring opening of caprolactam;

[0123] The polyamide B structure is formed by hexamethylenediamine and isophthalic acid;

[0124] The structure of antimicrobial agent C is formed by 2-(carboxyethyl)triphenylphosphonium bromide containing a carboxylic acid group and hexamethylenediamine.

[0125] Comparative Example 1

[0126] The difference from Example 1 is that the structure of polyamide A is formed by hexamethylenediamine and adipic acid, and the other parts remain unchanged.

[0127] Comparative Example 2

[0128] The difference from Example 1 is that the structure of polyamide A is formed by hexamethylenediamine and 1,10-sebacic acid, and the other parts remain unchanged.

[0129] Comparative Example 3

[0130] The difference from Example 1 is that the polyamide B structure is not contained, and the other parts remain unchanged.

[0131] Comparative Example 4

[0132] The difference from Example 1 is that the polyamide C structure is not contained, and the other parts remain unchanged.

[0133] The preparation method of the copolyamide of the above embodiment and comparative example specifically comprises the following steps:

[0134] (1) Salt solution preparation steps

[0135] The polyamide A salt solution is prepared by dissolving the diamine and diamine in a solvent according to the above examples and comparative examples. The solution temperature is controlled at 55° C. and the mass percentage is controlled at 40%.

[0136] A solution of polyamide B salt and / or lactam b3, wherein the embodiments and comparative examples of the polyamide B structure formed by dibasic acid and diamine are dissolved in desalted water to form a salt solution according to the dibasic acid and diamine of the above embodiments and comparative examples; wherein the embodiments and comparative examples of the polyamide b3 structure formed by lactam ring opening are dissolved in desalted water to form a lactam solution according to the above embodiments and comparative examples, wherein comparative examples 3 and 4 do not add a solution containing polyamide B salt and / or lactam b3; the solution temperature is controlled at 55°C, and the mass percentage is controlled at 40% respectively.

[0137] The solution containing the antibacterial agent C salt is prepared by dissolving the antibacterial agent and diamine in desalted water according to the above-mentioned embodiments and comparative examples to form a salt solution, wherein the antibacterial agent is directly dispersed in the desalted water in Embodiment 7 and Embodiment 8; the solution temperature is controlled at 55°C, and the mass percentage is controlled at 20%.

[0138] (2) Polymerization step

[0139] In the presence of nitrogen, a solution containing polyamide A salt and a solution containing polyamide B salt and / or lactam b3 are mixed, and then polymerized and evaporated and concentrated at a temperature of 145° C. and a pressure of 0.25 MPa to a mass percentage of 75% of the solution;

[0140] A solution containing the antibacterial agent C salt was added and continued to mix. The polymerization reaction was continued at a temperature of 170° C. and a pressure of 1.6 MPa. Finally, the pressure was reduced to room temperature to obtain copolymer polyamide.

[0141] Polyamide was prepared according to the above examples and comparative examples, and the performance of the polyamide samples was tested. The test methods and standards for various performance parameters are as follows:

[0142] 1. Melting point: ASTM D3418.

[0143] 2. Viscosity number: ISO 307.

[0144] 3. Mechanical properties: The tensile strength is tested according to ISO527 standard, and the simply supported beam impact strength is tested according to ISO 179 standard.

[0145] 4. Antibacterial performance: Refer to QB / T 2591-2003A "Test method and antibacterial effect of antibacterial plastics", use Escherichia coli ATCC 25922 to test the antibacterial rate after 24 hours; place the sample at 85% relative humidity and 85°C for 500 hours and then test its antibacterial rate.

[0146] The performance test results are as follows:

[0147]

[0148]

Claims

1. An antibacterial copolymer polyamide, characterized in that A polyamide A structure formed by hexamethylenediamine and dodecanedioic acid, at least one polyamide B structure other than polyamide A, and an antimicrobial agent C structure; The polyamide B structure is formed by at least one dibasic acid b1 and at least one diamine b2, and / or by ring-opening of lactam b3; The structure of the antibacterial agent C contains a quaternary phosphonium salt group, and is formed by a quaternary phosphonium salt antibacterial agent containing a carboxylic acid group and a diamine b2.

2. The antibacterial copolymer polyamide according to claim 1, characterized in that: The mass ratio of the polyamide A structure to the antibacterial copolymer polyamide is 70% to 95%; The mass ratio of the polyamide B structure to the antibacterial copolymer polyamide is 4% to 29%; The mass ratio of the antibacterial agent C structure to the antibacterial copolymer polyamide is 0.2% to 1%; The melting point of the antibacterial copolymer polyamide is 180°C to 210°C.

3. The antibacterial copolymer polyamide according to claim 1, characterized in that The dibasic acid b1 includes aromatic dibasic acids, preferably, at least one of terephthalic acid, terephthalic acid, terephthalic acid, isophthalic acid, isophthalic acid, phthalic acid, and phthalic acid.

4. The antibacterial copolymer polyamide according to claim 1, characterized in that The diamine b2 independently includes C2-C14 diamines, preferably, one or more of pentamethylenediamine, hexamethylenediamine, octanediamine, decanediamine, and 1,12-diaminododecane.

5. The antibacterial copolymer polyamide according to claim 1, characterized in that The lactam b3 includes at least one of butyrolactam, valerolactam, caprolactam, capryllactam, lauryl lactam, N-methyl caprolactam, N-vinyl caprolactam and 4-tert-butyl caprolactam.

6. The antibacterial copolymer polyamide according to claim 1, characterized in that The quaternary phosphonium salt antibacterial agent containing a carboxylic acid group includes tributyl carboxymethyl phosphonium chloride and / or 2-(carboxyethyl) triphenyl phosphonium bromide.

7. A method for preparing an antibacterial copolymer polyamide as claimed in claim 1 or 2, characterized in that: The preparation method is: In the presence of protective gas, a solution containing polyamide A salt, a solution containing polyamide B salt and / or lactam b3 and a solution containing antibacterial agent C salt are mixed to form a mixed solution, and the mixed solution is polymerized to form an antibacterial copolymer polyamide.

8. The method for preparing an antibacterial copolymer polyamide according to claim 7, characterized in that: The solution containing polyamide A salt is prepared by dissolving hexamethylenediamine and dodecanedioic acid in a solvent to form a salt solution; The solution containing the polyamide B salt is prepared by dissolving at least one dibasic acid b1, at least one diamine b2 and / or lactam b3 in a solvent to form a salt solution. The antibacterial agent C salt solution is prepared by dissolving a quaternary phosphonium salt antibacterial agent containing a carboxylic acid group and a diamine b2 in a solvent to form a salt solution.

9. The method for preparing an antibacterial copolymer polyamide according to claim 7, characterized in that: The protective gas includes one or more of nitrogen, carbon dioxide, argon and helium, and does not participate in the polymerization reaction; the polymerization temperature is 150° C. to 280° C., and the pressure is 0 to 2.0 MPa.

10. The method for preparing an antibacterial copolymer polyamide according to claim 7, characterized in that: The solvent includes water.

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