Antibacterial nylon 6 material as well as preparation method and application thereof

Abstract

The invention discloses an antibacterial nylon 6 material as well as a preparation method and application thereof, relates to the technical field of nylon materials, and solves the problem that the antibacterial property and the mechanical property of nylon are difficult to consider at the same time. The material has a structure shown as a formula (I), R1 and R2 are independently selected from one of C1-24 linear chain / branched chain aliphatic groups, substituted / unsubstituted C3-12 alicyclic hydrocarbon groups / C6-18 aryl groups / C7-30 aralkyl groups, or R1 and R2 on the same N and connected N form 5-7-membered saturated / unsaturated heterocyclic rings; and each E-group is independently selected from the structural general formula (II). Each R3 is independently selected from one of C1-24 linear chain / branched chain aliphatic groups, substituted / unsubstituted C3-12 alicyclic hydrocarbon groups, C6-18 aryl groups and C7-30 aralkyl groups; x is an integer selected from 1 to 18; m is equal to 0.01-0.50, and m + n is equal to 1. The antibacterial nylon 6 material has a broad-spectrum and efficient antibacterial effect, is lasting in antibacterial effect and excellent in mechanical property, and can be used for preparing textiles, daily necessities, building materials, packaging materials or panels. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to the technical field of functional nylon materials, and particularly relates to an antibacterial nylon 6 material, its preparation method and application. Background Art

[0002] Nylon is a type of synthetic polymer material with repeating amide groups (-CONH-) in its molecular main chain. Due to its excellent comprehensive properties, it is widely used in multiple industrial fields. This type of polymer has outstanding characteristics such as light weight, high strength and toughness, and wear resistance. At the same time, it exhibits good chemical corrosion resistance, barrier properties and thermal stability. Coupled with its excellent processability, it has become an indispensable engineering material in fields such as automotive manufacturing, textile industry, aerospace, construction, electrical and electronics, and industrial machinery.

[0003] Among many nylon varieties, nylon 6 has long dominated the market due to its excellent mechanical properties and relatively low production cost. However, due to the limitation of the molecular main chain structure, nylon 6 usually shows high hygroscopicity, and a slightly wet environment is easily formed on the surface, thus providing favorable conditions for the growth of microorganisms such as bacteria and fungi. This problem of microorganism growth not only accelerates material aging and reduces the service life of products, but more seriously, it may cause microbial contamination, posing a potential threat to the health and safety of users, especially prominent in sensitive application fields such as medical and food packaging.

[0004] To address this technical problem, the research and development of antibacterial modified nylon 6 has become an important research direction in the field of nylon materials. Currently, the antibacterial nylon products on the market mainly adopt the physical blending method, in which small molecule antibacterial agents (such as silver ions, copper ions, etc.) are compounded with the nylon matrix. However, these traditional antibacterial materials have obvious limitations. On the one hand, metal ions may migrate and precipitate, bringing safety and environmental risks; on the other hand, the antibacterial components are easily lost, resulting in the difficulty of maintaining long-term antibacterial efficacy. Therefore, the development of new nylon materials with high safety, environmental friendliness and long-term antibacterial performance has important scientific significance and application value.

[0005] Recent research has reported innovative chemical modification methods. ACS Macro Lett. 2022, 11, 46 - 52 first proposed introducing dimethylamino functional groups into the side chains of nylon 6 through ring - opening copolymerization of seven - membered cyclic lysine monomers and caprolactam, and then generating a quaternary ammonium cation structure with antibacterial activity through quaternization reaction with ethyl bromide. Similarly, Chinese patent document CN115707727A also discloses a technical method for preparing antibacterial nylon 6 by quaternization after ring - opening copolymerization of seven - membered cyclic lysine monomers and caprolactam. Although these methods have successfully endowed the materials with excellent broad - spectrum antibacterial properties, the introduction of quaternary ammonium cation side groups often disrupts the regularity of the nylon molecular chain, resulting in a decrease in the crystallinity of the material and thus affecting its mechanical properties. This trade - off relationship between antibacterial performance and mechanical properties severely restricts the practical application effect of antibacterial nylon 6.

[0006] Based on the above - mentioned technical status quo, developing a new quaternization modification method has become the key breakthrough point in current research. An ideal solution should achieve two goals: on the one hand, it is necessary to ensure that the material obtains efficient and durable antibacterial ability; on the other hand, it is necessary to maintain or even improve the original mechanical properties of nylon 6. The breakthrough of this technical problem will significantly expand the application prospects of antibacterial nylon 6 in fields with high - performance requirements. Summary of the Invention

[0007] In order to solve the technical problem that it is difficult to balance the antibacterial performance and mechanical properties of existing nylon materials, the present invention proposes an antibacterial nylon material, its preparation method and application.

[0008] The technical solution of the present invention is as follows:

[0009] An antibacterial nylon 6 material having the structure shown in the following formula (I):

[0010]

[0011] Wherein, each R1 group and R2 group are independently selected from one of a straight - chain / branched - chain aliphatic hydrocarbon group, a substituted / unsubstituted C 1～24 alicyclic hydrocarbon group, a substituted / unsubstituted C 3～12 aryl group, a substituted / unsubstituted C 6～18 aralkyl group, or the R1 and R2 groups on the same N atom and the connected N atom together form a 5 - 7 - membered saturated / unsaturated heterocycle; 7～30 Each E

[0012] group is independently selected from one or more of the following anion structure general formulas (II): - Wherein

[0013]

[0014] Wherein represents a bonding site; each R3 group is independently selected from C 1～24 a linear / branched aliphatic hydrocarbon group, a substituted / unsubstituted C 3～12 alicyclic hydrocarbon group, a substituted / unsubstituted C 6～18 aryl group, a substituted / unsubstituted C 7～30 aralkyl group;

[0015] x represents the number of CH2 repeating units in formula (I) and is selected from any integer from 1 to 18; m and n represent the molar ratio of the repeating unit having the structure to the total repeating units and the molar ratio of the repeating unit having the structure to the total repeating units, m = 0.01 - 0.50, n = 0.50 - 0.99, and m + n = 1;

[0016] The substitution means that the group is substituted by one or more substituents, and the substituent is C 1～18 a linear or branched alkyl group.

[0017] Preferably, each R1 group and R2 group are independently selected from C 1～12 a linear / branched aliphatic hydrocarbon group, a substituted / unsubstituted C 3～6 alicyclic hydrocarbon group, a substituted / unsubstituted C 6～10 aryl group, a substituted / unsubstituted C 7～16 aralkyl group, or the R1 and R2 groups on the same N atom together with the connected N atom form a 5 - 6 membered saturated / unsaturated heterocycle;

[0018] Each R3 group is independently selected from C 1～12 a linear / branched aliphatic hydrocarbon group, a substituted / unsubstituted C 3～6 alicyclic hydrocarbon group, a substituted / unsubstituted C 6～10 aryl group, a substituted / unsubstituted C 7～16 aralkyl group.

[0019] Preferably, each R1 group and R2 group are independently selected from one of methyl, ethyl, propyl, butyl, hexyl, octyl, dodecyl, allyl, phenyl, benzyl, or the R1 and R2 groups on the same N atom together with the connected N atom form a pyrrolidinyl or piperidinyl group;

[0020] Each R3 group is independently selected from one of methyl, ethyl, propyl, butyl, hexyl, octyl, dodecyl, cyclohexyl, phenyl, benzyl.

[0021] Preferably, the total number of each repeating unit in formula (I) is from 10 to 2500, more preferably from 20 to 1000, and most preferably from 20 to 500.

[0022] Preferably, the antibacterial nylon 6 material has a number-average molecular weight of 1,000 to 500,000, more preferably 5,000 to 200,000, and most preferably 5,000 to 50,000.

[0023] The present invention also provides a method for preparing the above antibacterial nylon 6 material, comprising the following steps:

[0024] S1. React 6-aminocaprolactam shown in the structural formula (Ⅲ) with one or more of aldehydes and / or halogenated hydrocarbons having R1 and / or R2 groups to obtain a cyclic lysine monomer having the structure shown in the following formula (Ⅳ):

[0025]

[0026] S2. Carry out ring-opening polymerization reaction on the cyclic lysine monomer and caprolactam monomer in a molar ratio of 1:1 to 99 under the action of a catalyst and an activator to obtain a copolymer having the structure shown in the following formula (V):

[0027]

[0028] S3. React the copolymer with an electrophilic reagent having a heterocycle shown in the following formula (Ⅵ), and the reaction product is sedimented, centrifuged and dried in ethyl acetate / ether to obtain the antibacterial nylon 6 material:

[0029]

[0030] The structure of the electrophilic reagent having a heterocycle shown in the formula (Ⅵ) is preferably one or more of propiolactone, 1,3-propane sultone, ethylene carbonate, and ethoxyphospholane-2-one.

[0031] Preferably, the catalyst in step S2 is selected from one or more of carbene reagents, guanidine reagents, amidine reagents, phosphazene reagents, alkali metals, alkali metal oxides, alkali metal hydroxides, alkali metal hydrides, alkali metal alkoxides, alkaline earth metals, alkaline earth metal oxides, alkaline earth metal hydroxides, alkaline earth metal hydrides, and alkaline earth metal alkoxides; more preferably one or more of sodium hydride, potassium hydride, t-BuP4, potassium tert-butoxide, sodium methoxide, potassium methoxide, DBU, TBD, sodium, and potassium.

[0032] Preferably, the activator in step S2 has the structure shown in the following formula (Ⅶ):

[0033]

[0034] Among them, R4 is selected from one of methyl, ethyl, phenyl, tert-butylphenyl, and trifluoromethylphenyl.

[0035] Preferably, the total amount of the cyclic lysine monomer and the caprolactam monomer, and the molar ratio of the catalyst to the activator is (10 - 50):1:1; more preferably (10 - 30):1:1.

[0036] Preferably, the reaction conditions for the ring-opening polymerization reaction in step S2 are: the reaction temperature is 140 - 180 °C, and the reaction time is 3 - 6 h.

[0037] Preferably, the reaction in step S3 is carried out in one or more of the solvents methanol, ethanol, isopropanol, n-butanol, trifluoroethanol, hexafluoroisopropanol, perfluorotert-butanol, benzyl alcohol, ethylene glycol, cyclohexanol; the reaction conditions for the reaction are: the reaction temperature is 40 - 70 °C, and the reaction time is 10 - 12 h.

[0038] The present invention also provides an application of the above antibacterial nylon 6 material, specifically applied to the preparation of textiles, daily necessities, building materials, packaging materials or panels.

[0039] Compared with the prior art, the specific beneficial effects of the present invention are:

[0040] The present invention adopts an innovative molecular design strategy, and through the specific reaction of a heterocyclic compound as an electrophilic reagent with the side-chain amino group of the copolyamide, an antibacterial nylon material with a unique quaternary ammonium inner salt structure is successfully constructed. Different from the technical route in the prior art where quaternization with halogenated hydrocarbons leads to the free halogen counterions in the polymer system, the effects of the present invention are mainly reflected in the following aspects:

[0041] 1. Through precise molecular design, the present invention enables the counteranion of the quaternary ammonium group to be firmly bonded to the main chain of the copolyamide through a covalent bond, forming a stable quaternary ammonium inner salt structure. This unique molecular configuration significantly improves the stability of the charged groups, avoids the loss of antibacterial components; promotes the orderly aggregation of the side-chain charged groups through electrostatic interaction; forms a physical cross-linked network structure, which produces a synergistic effect with the hydrogen bond network of the main-chain amide groups.

[0042] 2. Antibacterial performance: It exhibits broad-spectrum and high-efficiency antibacterial activity, and has a significant inhibitory effect on Gram-positive bacteria, Gram-negative bacteria and fungi; long-term stability: the inner salt structure ensures the long-term stability of the antibacterial performance, and still maintains excellent antibacterial effects after multiple washes or long-term use; mechanical properties: the formation of the physical cross-linked network brings an enhancement effect to the material, and its key mechanical indexes such as tensile strength, modulus and impact toughness are superior to those of conventional quaternized nylon materials.

[0043] 3. The present invention maintains the excellent processing performance of nylon materials and can be formed by conventional processing methods such as injection molding, blow molding, extrusion molding, and spinning. It is suitable for preparing various forms of products such as fibers, films, sheets, and pipes, and has broad application prospects in the fields of textiles (such as medical protective clothing, antibacterial socks, etc.), daily necessities (kitchen utensils, bathroom products), building materials (antibacterial floors, wall panels), packaging materials (food packaging, medical packaging), and electronic device panels.

[0044] 4. The raw materials of the present invention are easily available and the cost is controllable. The preparation process is simple, has good compatibility with the existing nylon production line, is easy to realize large-scale production, and has significant economic benefits and market competitiveness.

[0045] The present invention successfully solves the technical problem that it is difficult to balance the antibacterial performance and mechanical properties in traditional antibacterial nylon materials, and provides a new technical route for the development of high-performance antibacterial polymer materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a schematic diagram of the synthesis route of the antibacterial nylon 6 material of the present invention;

[0047] Figure 2 is a schematic diagram of the antibacterial effect of the nylon 6 materials prepared in Example 1 and Comparative Example 1 against Staphylococcus aureus. DETAILED DESCRIPTION OF THE INVENTION

[0048] To make the technical solutions of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the specification drawings of the present invention. It should be noted that the following embodiments are only used to better understand the technical solutions of the present invention and should not be construed as a limitation of the present invention.

[0049] Any specific numerical value (including the endpoints of the numerical range) disclosed in this article is not limited to the exact value of the numerical value, but should be understood to also cover values close to the exact value, such as all possible numerical values within ±5% of the exact value. And for the disclosed numerical range, any combination can be made between the endpoint values of the range, between the endpoint values and the specific point values within the range, and between the specific point values to obtain one or more new numerical ranges, and these new numerical ranges should also be regarded as specifically disclosed in this article.

[0050] Unless otherwise specified, the terms used in this article have the same meaning as those generally understood by those skilled in the art. If the terms are defined in this article and their definitions are different from the general understanding in the art, the definitions in this article shall prevail.

[0051] In this article, except for what is clearly stated, any matters or things not mentioned shall directly apply to those known in the art without any changes. Moreover, any embodiment described herein can be freely combined with one or more other embodiments described herein, and the technical solutions or technical ideas formed thereby shall be regarded as part of the original disclosure or original record of the present invention, and shall not be regarded as new content not disclosed or anticipated herein, unless those skilled in the art consider such combination to be obviously unreasonable.

[0052] Example 1.

[0053] (1) Preparation of dimethyl-protected aminocaprolactam (DMCL)

[0054] Weigh 600 g (4.68 mol) of aminocaprolactam and dissolve it in 10 L of methanol. Add 840 g (10.28 mol) of formaldehyde solution (mass fraction 37%) and 60 g of 10% palladium on carbon, and react under a hydrogen atmosphere for 24 h. Filter by suction, concentrate, and recrystallize to obtain dimethyl-protected aminocaprolactam with a yield of 95%, and its purity is greater than 99% according to 1H NMR analysis.

[0055] (2) Preparation of copolyamide

[0056] Weigh 1.0 g (6.4 mmol) of the dimethyl-protected aminocaprolactam (DMCL) prepared in step (1), 13.7 g (121.6 mmol) of caprolactam (CL), and 0.74 g (3.4 mmol) of N-benzoylcaprolactam activator into a 25 ml round-bottom flask. After evacuating and replacing the gas at 40 °C for 30 min, add 140 mg (3.4 mmol) of sodium hydride, protect with nitrogen, and react in an oil bath at 180 °C for 6 h. Add 100 ml of trifluoroethanol to dissolve the polymer, precipitate it in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain 14.6 g (about 95%) of the copolymer.

[0057] Results of NMR characterization: 1 1H NMR (500 MHz, TFA / DMSO-d6, 5:95, v:v) δ 3.70 - 3.61, 3.13 - 3.02, 2.76 - 2.72, 2.21 - 2.00, 1.81 - 1.18. The inserted molar ratio of dimethylaminocyclohexyl lysine in the obtained copolymer was calculated to be about 4% by comparing the proton integral areas of the chemical shifts 3.70 - 3.61 and 2.21 - 2.00.

[0058] (3) Preparation of antibacterial nylon 6 material

[0059] Weigh 2.5 g of copolyamide (containing 4% DMCL), dissolve it in 50 mL of trifluoroethanol, add 0.24 g of propiolactone, and reflux it under heating for 24 h. After the reaction is complete, the solution is precipitated in a mixed solvent of ethyl acetate / ether, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-1, with a yield of 90%, a number-average molecular weight of 30.5 kDa, and the molar content of the quaternary ammonium inner salt side group being about 4%.

[0060] Weigh 2.5 g of copolyamide (containing 4% DMCL), dissolve it in 50 mL of trifluoroethanol, add 0.40 g of 1,3-propanesultone, and reflux it under heating for 24 h. After the reaction is complete, the solution is precipitated in a mixed solvent of ethyl acetate / ether, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-2, with a yield of 91%, a number-average molecular weight of 31.2 kDa, and the molar content of the quaternary ammonium inner salt side group being about 4%.

[0061] Weigh 2.5 g of copolyamide (containing 4% DMCL), dissolve it in 50 mL of trifluoroethanol, add 0.29 g of ethylene carbonate, and reflux it under heating for 24 h. After the reaction is complete, the solution is precipitated in a mixed solvent of ethyl acetate / ether, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-3, with a yield of 89%, a number-average molecular weight of 29.2 kDa, and the molar content of the quaternary ammonium inner salt side group being about 4%.

[0062] Weigh 2.5 g of copolyamide (containing 4% DMCL), dissolve it in 50 mL of trifluoroethanol, add 0.49 g of ethoxyphospholene oxide, and reflux it under heating for 24 h. After the reaction is complete, the solution is precipitated in a mixed solvent of ethyl acetate / ether, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-4, with a yield of 90%, a number-average molecular weight of 35.0 kDa, and the molar content of the quaternary ammonium inner salt side group being about 4%.

[0063] Example 2.

[0064] Weigh 10 mmol of the prepared dimethyl-protected aminocaprolactam (DMCL) in step (1) of Example 1, 90 mmol of caprolactam (CL), and 5 mmol of N-benzoylcaprolactam activator into a 25 ml round-bottom flask. After evacuating and replacing the gas at 40 °C for 30 min, add 5 mmol of sodium hydride, and react it under nitrogen protection in an oil bath at 180 °C for 6 h. Add 100 ml of trifluoroethanol to dissolve the polymer, precipitate it in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the copolymer product, with a yield of about 92%.

[0065] NMR characterization results: 11H NMR (500 MHz, TFA / DMSO-d6, 5:95, v:v) δ 3.70 - 3.61, 3.13 - 3.02, 2.76 - 2.72, 2.21 - 2.00, 1.81 - 1.18. The insertion molar ratio of dimethylamino-cyclic lysine in the obtained copolymer was calculated by comparing the proton integration area at chemical shift 3.70 - 3.61 with that at 2.21 - 2.00, and it was approximately 8%.

[0066] Weighed 2.5 g of copolyamide (containing 8% DMCL), dissolved it in 50 mL of trifluoroethanol, added 0.48 g of propiolactone, and refluxed it for 24 h. After the reaction was complete, the solution was precipitated in a mixed solvent of ethyl acetate / ether, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-5, with a yield of 90%, a number-average molecular weight of 28.5 kDa, and the molar content of the quaternary inner salt side group was approximately 8%.

[0067] Weighed 2.5 g of copolyamide (containing 8% DMCL), dissolved it in 50 mL of trifluoroethanol, added 0.80 g of 1,3-propanesultone, and refluxed it for 24 h. After the reaction was complete, the solution was precipitated in a mixed solvent of ethyl acetate / ether, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-6, with a yield of 89%, a number-average molecular weight of 28.8 kDa, and the molar content of the quaternary inner salt side group was approximately 8%.

[0068] Weighed 2.5 g of copolyamide (containing 8% DMCL), dissolved it in 50 mL of trifluoroethanol, added 0.60 g of ethylene carbonate, and refluxed it for 24 h. After the reaction was complete, the solution was precipitated in a mixed solvent of ethyl acetate / ether, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-7, with a yield of 91%, a number-average molecular weight of 30.8 kDa, and the molar content of the quaternary inner salt side group was approximately 8%.

[0069] Weighed 2.5 g of copolyamide (containing 8% DMCL), dissolved it in 50 mL of trifluoroethanol, added 1.00 g of ethoxyphospholene oxide, and refluxed it for 24 h. After the reaction was complete, the solution was precipitated in a mixed solvent of ethyl acetate / ether, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-8, with a yield of 92%, a number-average molecular weight of 33.4 kDa, and the molar content of the quaternary inner salt side group was approximately 8%.

[0070] Example 3.

[0071] Weigh 20 mmol of the dimethyl-protected aminocaprolactam (DMCL) prepared in step (1) of Example 1, 80 mmol of caprolactam (CL), and 5 mmol of N-benzoylcaprolactam activator into a 25 ml round-bottom flask. After purging with gas at 40 °C for 30 min, add 5 mmol of sodium hydride, and react under nitrogen protection in an oil bath at 180 °C for 6 h. Add 100 ml of trifluoroethanol to dissolve the polymer, precipitate it in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the copolymer product with a yield of about 92%.

[0072] NMR characterization results: 1 H NMR (500 MHz, TFA / DMSO-d6, 5:95, v:v) δ 3.70 - 3.61, 3.13 - 3.02, 2.76 - 2.72, 2.21 - 2.00, 1.81 - 1.18. The insertion molar ratio of dimethylamino-cyclic lysine in the obtained copolymer was calculated to be about 18% by comparing the proton integral area at chemical shift 3.70 - 3.61 with the proton integral area at 2.21 - 2.00.

[0073] Weigh 2.5 g of the copolyamide (containing 18% DMCL) and dissolve it in 50 mL of trifluoroethanol. Add 1.08 g of propiolactone and reflux for 24 h. After the reaction is complete, precipitate the solution in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the quaternized antibacterial nylon 6 material CP-9 with a yield of 90%, a number-average molecular weight of 25.3 kDa, and a molar content of quaternary inner salt side groups of about 18%.

[0074] Weigh 2.5 g of the copolyamide (containing 18% DMCL) and dissolve it in 50 mL of trifluoroethanol. Add 2.0 g of 1,3-propane sultone and reflux for 24 h. After the reaction is complete, precipitate the solution in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the quaternized antibacterial nylon 6 material CP-10 with a yield of 88%, a number-average molecular weight of 27.6 kDa, and a molar content of quaternary inner salt side groups of about 18%.

[0075] Weigh 2.5 g of the copolyamide (containing 18% DMCL) and dissolve it in 50 mL of trifluoroethanol. Add 1.5 g of ethylene carbonate and reflux for 24 h. After the reaction is complete, precipitate the solution in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the quaternized antibacterial nylon 6 material CP-11 with a yield of 90%, a number-average molecular weight of 28.2 kDa, and a molar content of quaternary inner salt side groups of about 18%.

[0076] Weigh 2.5 g of copolyamide (containing 18% DMCL), dissolve it in 50 mL of trifluoroethanol, add 2.5 g of ethoxyphospholane-2-one, and reflux under heating for 24 h. After the reaction is complete, the solution is precipitated in an ethyl acetate / ethyl ether mixed solvent, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-12, with a yield of 87%, a number-average molecular weight of 27.4 kDa, and a molar content of the quaternary inner salt side group of about 18%.

[0077] Example 4.

[0078] Weigh 30 mmol of the prepared dimethyl-protected aminocaprolactam (DMCL) from step (1) of Example 1, 70 mmol of caprolactam (CL), and 5 mmol of N-benzoylcaprolactam activator into a 25 ml round-bottom flask. After evacuating and replacing the gas at 40 °C for 30 min, add 5 mmol of sodium hydride, protect with nitrogen, and react in an oil bath at 180 °C for 6 h. Add 100 ml of trifluoroethanol to dissolve the polymer, precipitate it in an ethyl acetate / ethyl ether mixed solvent, centrifuge, and dry to obtain the copolymer product, with a yield of about 90%.

[0079] NMR characterization results: 1 H NMR (500 MHz, TFA / DMSO-d6, 5:95, v:v) δ 3.70 - 3.61, 3.13 - 3.02, 2.76 - 2.72, 2.21 - 2.00, 1.81 - 1.18. By comparing the proton integration area at 3.70 - 3.61 with the proton integration area at 2.21 - 2.00, the insertion molar ratio of dimethylaminocyclolysine in the obtained copolymer is calculated to be about 27%.

[0080] Weigh 2.5 g of copolyamide (containing 27% DMCL), dissolve it in 50 mL of trifluoroethanol, add 1.50 g of propiolactone, and reflux under heating for 24 h. After the reaction is complete, the solution is precipitated in an ethyl acetate / ethyl ether mixed solvent, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-13, with a yield of 89%, a number-average molecular weight of 22.3 kDa, and a molar content of the quaternary inner salt side group of about 27%.

[0081] Weigh 2.5 g of copolyamide (containing 27% DMCL), dissolve it in 50 mL of trifluoroethanol, add 3.0 g of 1,3-propanesultone, and reflux under heating for 24 h. After the reaction is complete, the solution is precipitated in an ethyl acetate / ethyl ether mixed solvent, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-14, with a yield of 90%, a number-average molecular weight of 24.6 kDa, and a molar content of the quaternary inner salt side group of about 27%.

[0082] Weigh 2.5 g of the copolyamide (containing 27% DMCL) and dissolve it in 50 mL of trifluoroethanol. Add 2.5 g of ethylene carbonate and reflux for 24 h. After the reaction is complete, precipitate the solution in an ethyl acetate / ethyl ether mixed solvent, centrifuge, and dry to obtain the quaternized antibacterial nylon 6 material CP-15 with a yield of 90%, a number-average molecular weight of 23.2 kDa, and the molar content of the inner salt side group of the quaternary ammonium being approximately 27%.

[0083] Weigh 2.5 g of the copolyamide (containing 27% DMCL) and dissolve it in 50 mL of trifluoroethanol. Add 4.0 g of ethoxyphospholane-2-one and reflux for 24 h. After the reaction is complete, precipitate the solution in an ethyl acetate / ethyl ether mixed solvent, centrifuge, and dry to obtain the quaternized antibacterial nylon 6 material CP-16 with a yield of 92%, a number-average molecular weight of 25.4 kDa, and the molar content of the inner salt side group of the quaternary ammonium being approximately 27%.

[0084] Example 5.

[0085] (1) Preparation of diethyl-protected aminohexanolactam (DECL)

[0086] Weigh 300 g (2.34 mol) of aminohexanolactam and dissolve it in 5 L of methanol. Add 566 g (5.14 mol) of an acetaldehyde solution (mass fraction 40%) and 30 g of 10% palladium on carbon, and react under a hydrogen atmosphere for 24 h. Filter by suction, concentrate, and recrystallize to obtain diethyl-protected aminohexanolactam with a yield of 92%, and its purity is greater than 99% according to 1H NMR analysis.

[0087] (2) Preparation of copolyamide

[0088] Weigh 5 mmol of the diethyl-protected aminohexanolactam (DECL) prepared in step (1), 95 mmol of caprolactam (CL), and 5 mmol of N-benzoylcaprolactam activator in a 25 ml round-bottom flask. After purging with gas at 40 °C for 30 min, add 5 mmol of sodium hydride, protect with nitrogen, and react in an oil bath at 180 °C for 6 h. Add 100 ml of trifluoroethanol to dissolve the polymer, precipitate in an ethyl acetate / ethyl ether mixed solvent, centrifuge, and dry to obtain the copolymer product with a yield of approximately 90%.

[0089] 1H NMR characterization results: 1 H NMR (500 MHz, TFA / DMSO-d6, 5:95, v:v) δ 3.80 - 3.71, 3.23 - 3.12, 2.86 - 2.82, 2.21 - 2.00, 1.81 - 1.15. The inserted molar ratio of diethylamino-cyclic lysine in the obtained copolymer was calculated by comparing the proton integral area of chemical shift 3.80 - 3.71 with the proton integral area of 2.21 - 2.00 to be approximately 4%.

[0090] (3) Preparation of Antibacterial Nylon 6 Material

[0091] Weigh 2.0 g of copolyamide (containing 4% DECL) and dissolve it in 50 mL of trifluoroethanol. Add 1.00 g of propiolactone and reflux for 24 h. After the reaction is complete, the solution is precipitated in a mixed solvent of ethyl acetate / ether, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-17 with a yield of 88%, a number-average molecular weight of 24.3 kDa, and the molar content of the quaternary inner salt side group is about 4%.

[0092] Weigh 2.0 g of copolyamide (containing 4% DECL) and dissolve it in 50 mL of trifluoroethanol. Add 1.20 g of 1,3-propane sultone and reflux for 24 h. After the reaction is complete, the solution is precipitated in a mixed solvent of ethyl acetate / ether, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-18 with a yield of 92%, a number-average molecular weight of 25.6 kDa, and the molar content of the quaternary inner salt side group is about 4%.

[0093] Weigh 2.0 g of copolyamide (containing 4% DECL) and dissolve it in 50 mL of trifluoroethanol. Add 0.9 g of ethylene carbonate and reflux for 24 h. After the reaction is complete, the solution is precipitated in a mixed solvent of ethyl acetate / ether, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-19 with a yield of 92%, a number-average molecular weight of 22.2 kDa, and the molar content of the quaternary inner salt side group is about 4%.

[0094] Weigh 2.0 g of copolyamide (containing 4% DECL) and dissolve it in 50 mL of trifluoroethanol. Add 1.08 g of ethoxyphospholane-2-one and reflux for 24 h. After the reaction is complete, the solution is precipitated in a mixed solvent of ethyl acetate / ether, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-20 with a yield of 91%, a number-average molecular weight of 26.4 kDa, and the molar content of the quaternary inner salt side group is about 4%.

[0095] Example 6.

[0096] (1) Preparation of Dipropyl-Protected Aminohexanolactam (DPCL)

[0097] Weigh 300 g (2.34 mol) of aminohexanolactam and dissolve it in 5 L of methanol. Add 299 g (5.14 mol) of propionaldehyde and 30 g of 10% palladium on carbon, and react under a hydrogen atmosphere for 24 h. Filter by suction, concentrate, perform column chromatography, and recrystallize to obtain dipropyl-protected aminohexanolactam with a yield of 90%. According to 1H NMR analysis, its purity is greater than 99%.

[0098] (2) Preparation of Copolyamide

[0099] Weigh 5 mmol of the dipropyl-protected amino-caprolactam (DPCL) prepared in step (1), 95 mmol of caprolactam (CL), and 5 mmol of N-benzoylcaprolactam activator into a 25 ml round-bottom flask. After purging with gas at 40 °C for 30 min, add 5 mmol of sodium hydride, and react under nitrogen protection in an oil bath at 180 °C for 6 h. Add 100 ml of trifluoroethanol to dissolve the polymer, precipitate it in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the copolymer product with a yield of about 90%.

[0100] NMR characterization results: 1 1H NMR (500 MHz, TFA / DMSO-d6, 5:95, v:v) δ 3.85 - 3.71, 3.25 - 3.12, 2.96 - 2.72, 2.21 - 2.00, 1.91 - 1.15. By comparing the proton integral areas of the chemical shifts 3.85 - 3.71 and 2.21 - 2.00, the insertion molar ratio of dipropylamino-cyclic lysine in the obtained copolymer was calculated to be approximately 5%.

[0101] (3) Preparation of antibacterial nylon 6 material

[0102] Weigh 2.2 g of the copolyamide (containing 5% DPCL) and dissolve it in 50 mL of trifluoroethanol. Add 1.00 g of propiolactone and reflux for 24 h. After the reaction is complete, precipitate the solution in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the quaternized antibacterial nylon 6 material CP-21 with a yield of 88%, a number-average molecular weight of 21.3 kDa, and a molar content of quaternary ammonium inner salt side groups of approximately 5%.

[0103] Weigh 2.2 g of the copolyamide (containing 5% DPCL) and dissolve it in 50 mL of trifluoroethanol. Add 1.20 g of 1,3-propane sultone and reflux for 24 h. After the reaction is complete, precipitate the solution in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the quaternized antibacterial nylon 6 material CP-22 with a yield of 92%, a number-average molecular weight of 22.6 kDa, and a molar content of quaternary ammonium inner salt side groups of approximately 5%.

[0104] Weigh 2.2 g of the copolyamide (containing 5% DPCL) and dissolve it in 50 mL of trifluoroethanol. Add 0.9 g of ethylene carbonate and reflux for 24 h. After the reaction is complete, precipitate the solution in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the quaternized antibacterial nylon 6 material CP-23 with a yield of 92%, a number-average molecular weight of 23.2 kDa, and a molar content of quaternary ammonium inner salt side groups of approximately 5%.

[0105] Weigh 2.2 g of copolyamide (containing 5% DPCL), dissolve it in 50 mL of trifluoroethanol, add 1.08 g of ethoxyphospholane-2-one, and reflux it for 24 h. After the reaction is complete, the solution is precipitated in a mixed solvent of ethyl acetate / ether, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-24 with a yield of 91%, a number-average molecular weight of 24.4 kDa, and a molar content of the quaternary ammonium inner salt side group of about 5%.

[0106] Example 7.

[0107] (1) Preparation of dibenzyl-protected aminocaprolactam (DBCL)

[0108] Weigh 300 g (2.34 mol) of aminocaprolactam, dissolve it in 5 L of acetonitrile, add 560 mL (4.91 mol) of benzyl chloride and 468 g (3.51 mol) of potassium carbonate, and stir and react at 80 °C for 6 h. Wash it with 1 M HCl until neutral, extract it with dichloromethane, dry it with anhydrous sodium sulfate, filter it by suction, concentrate it, perform column chromatography, and recrystallize it to obtain dibenzyl-protected aminocaprolactam with a yield of 85%, and its purity is 95% according to 1H NMR analysis.

[0109] (2) Preparation of copolyamide

[0110] Weigh 5 mmol of the dibenzyl-protected aminocaprolactam (DBCL) prepared in step (1), 95 mmol of caprolactam (CL), and 5 mmol of N-benzoylcaprolactam activator in a 25 ml round-bottom flask. After evacuating and replacing the gas at 40 °C for 30 min, add 5 mmol of sodium hydride, protect it with nitrogen, and react in an oil bath at 180 °C for 6 h. Add 100 ml of trifluoroethanol to dissolve the polymer, precipitate it in a mixed solvent of ethyl acetate / ether, centrifuge it, and dry it to obtain the copolymer with a yield of about 90%.

[0111] NMR characterization results: 1 1H NMR (500 MHz, TFA / DMSO-d6, 5:95, v:v) δ 7.00 - 7.50, 3.85 - 2.8, 2.21 - 2.00, 1.91 - 1.20. The insertion molar ratio of dibenzylamino-cyclic lysine in the obtained copolymer was calculated to be about 5% by comparing the proton integral area at 7.00 - 7.50 with the proton integral area at 2.21 - 2.00.

[0112] (3) Preparation of antibacterial nylon 6 material

[0113] Weigh 3.0 g of copolyamide (containing 5% DBCL) and dissolve it in 50 mL of trifluoroethanol. Add 1.00 g of propiolactone and reflux for 24 h. After the reaction is complete, the solution is precipitated in a mixed solvent of ethyl acetate / ether, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-25 with a yield of 88%, a number-average molecular weight of 28.3 kDa, and the molar content of the inner quaternary salt side group is about 5%.

[0114] Weigh 3.0 g of copolyamide (containing 5% DBCL) and dissolve it in 50 mL of trifluoroethanol. Add 1.20 g of 1,3-propanesultone and reflux for 24 h. After the reaction is complete, the solution is precipitated in a mixed solvent of ethyl acetate / ether, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-26 with a yield of 92%, a number-average molecular weight of 29.6 kDa, and the molar content of the inner quaternary salt side group is about 5%.

[0115] Weigh 3.0 g of copolyamide (containing 5% DBCL) and dissolve it in 50 mL of trifluoroethanol. Add 0.9 g of ethylene carbonate and reflux for 24 h. After the reaction is complete, the solution is precipitated in a mixed solvent of ethyl acetate / ether, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-27 with a yield of 92%, a number-average molecular weight of 28.2 kDa, and the molar content of the inner quaternary salt side group is about 5%.

[0116] Weigh 3.0 g of copolyamide (containing 5% DBCL) and dissolve it in 50 mL of trifluoroethanol. Add 1.08 g of ethoxyphospholene oxide and reflux for 24 h. After the reaction is complete, the solution is precipitated in a mixed solvent of ethyl acetate / ether, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-28 with a yield of 91%, a number-average molecular weight of 34.4 kDa, and the molar content of the inner quaternary salt side group is about 5%.

[0117] Example 8.

[0118] (1) Preparation of diallyl-protected aminocaprolactam (DACL)

[0119] Weigh 300 g (2.34 mol) of aminocaprolactam and dissolve it in 5 L of acetonitrile. Add 594 g (4.91 mol) of allyl bromide and 468 g (3.51 mol) of potassium carbonate, and stir and react at 80 °C for 6 h. Wash with 1 M HCl until neutral, extract with dichloromethane, dry with anhydrous sodium sulfate, filter by suction, concentrate, perform column chromatography, and recrystallize to obtain diallyl-protected aminocaprolactam with a yield of 88% and a purity of 96% according to 1H NMR analysis.

[0120] (2) Preparation of copolyamide

[0121] Weigh 5 mmol of the diallyl-protected aminocaprolactam (DACL) prepared in step (1), 95 mmol of caprolactam (CL), and 5 mmol of N-benzoylcaprolactam activator into a 25 ml round-bottom flask. After purging with gas at 40 °C for 30 min, add 5 mmol of sodium hydride, protect with nitrogen, and react in an oil bath at 180 °C for 6 h. Add 100 ml of trifluoroethanol to dissolve the polymer, precipitate it in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the copolymer product with a yield of about 90%.

[0122] NMR characterization results: 1 1H NMR (500 MHz, TFA / DMSO-d6, 5:95, v:v) δ 6.00 - 5.80, 5.30 - 5.10, 3.90 - 2.6, 2.21 - 2.00, 1.91 - 1.20. By comparing the proton integral areas of 6.00 - 5.80 and 2.21 - 2.00 in chemical shifts, the insertion molar ratio of diallylamino-cyclic lysine in the obtained copolymer is calculated to be about 5%.

[0123] (3) Preparation of antibacterial nylon 6 material

[0124] Weigh 2.0 g of the copolyamide (containing 5% DACL) and dissolve it in 50 mL of trifluoroethanol. Add 1.20 g of propiolactone and reflux for 24 h. After the reaction is complete, precipitate the solution in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the quaternized antibacterial nylon 6 material CP-29 with a yield of 90%, a number-average molecular weight of 22.6 kDa, and the molar content of the quaternary inner salt side group is about 5%.

[0125] Weigh 2.0 g of the copolyamide (containing 5% DACL) and dissolve it in 50 mL of trifluoroethanol. Add 1.40 g of 1,3-propane sultone and reflux for 24 h. After the reaction is complete, precipitate the solution in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the quaternized antibacterial nylon 6 material CP-30 with a yield of 91%, a number-average molecular weight of 24.6 kDa, and the molar content of the quaternary inner salt side group is about 5%.

[0126] Weigh 2.0 g of the copolyamide (containing 5% DACL) and dissolve it in 50 mL of trifluoroethanol. Add 1.30 g of ethylene carbonate and reflux for 24 h. After the reaction is complete, precipitate the solution in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the quaternized antibacterial nylon 6 material CP-31 with a yield of 93%, a number-average molecular weight of 23.8 kDa, and the molar content of the quaternary inner salt side group is about 5%.

[0127] Weigh 2.0 g of copolyamide (containing 5% DACL) and dissolve it in 50 mL of trifluoroethanol. Add 1.50 g of ethoxyphospholane-2-one and reflux for 24 h. After the reaction is complete, the solution is precipitated in a mixed solvent of ethyl acetate / ether, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-32 with a yield of 90%, a number-average molecular weight of 24.5 kDa, and the molar content of the inner quaternary salt side group is about 5%.

[0128] Example 9.

[0129] (1) Preparation of N,N-hexahydropyridylamino-caprolactam (HPCL)

[0130] Weigh 300 g (2.34 mol) of amino-caprolactam and dissolve it in 5 L of acetonitrile. Add 807 g (3.51 mol) of 1,5-dibromopentane and 468 g (3.51 mol) of potassium carbonate, and stir and react at 80 °C for 6 h. Wash with 1 M HCl until neutral, extract with dichloromethane, dry with anhydrous sodium sulfate, filter by suction, concentrate, perform column chromatography, and recrystallize to obtain N,N-hexahydropyridylamino-caprolactam with a yield of 80% and a purity of 96% according to 1H NMR analysis.

[0131] (2) Preparation of copolyamide

[0132] Weigh 5 mmol of diallyl-protected amino-caprolactam (HPCL) prepared in step (1), 95 mmol of caprolactam (CL), and 5 mmol of N-benzoylcaprolactam activator in a 25 ml round-bottom flask. After purging with gas at 40 °C for 30 min, add 5 mmol of sodium hydride, protect with nitrogen, and react in an oil bath at 180 °C for 6 h. Add 100 ml of trifluoroethanol to dissolve the polymer, precipitate in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the copolymer with a yield of about 90%.

[0133] NMR characterization results: 1 1H NMR (500 MHz, TFA / DMSO-d6, 5:95, v:v) 3.90 - 3.73, 3.60 - 2.6, 2.21 - 2.00, 1.91 - 1.20. The inserted molar ratio of N,N-hexahydropyridylamino-caprolactam in the obtained copolymer is calculated to be about 5% by comparing the proton integration area of 3.90 - 3.73 with the proton integration area of 2.21 - 2.00.

[0134] (3) Preparation of antibacterial nylon 6 material

[0135] Weigh 2.5 g of copolyamide (containing 5% HPCL) and dissolve it in 50 mL of trifluoroethanol. Add 1.00 g of propiolactone and reflux for 24 h. After the reaction is complete, precipitate the solution in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the quaternized antibacterial nylon 6 material CP-33 with a yield of 93%, a number-average molecular weight of 21.7 kDa, and a molar content of quaternary ammonium inner salt side groups of approximately 5%.

[0136] Weigh 2.5 g of copolyamide (containing 5% HPCL) and dissolve it in 50 mL of trifluoroethanol. Add 1.20 g of 1,3-propanesultone and reflux for 24 h. After the reaction is complete, precipitate the solution in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the quaternized antibacterial nylon 6 material CP-34 with a yield of 90%, a number-average molecular weight of 22.1 kDa, and a molar content of quaternary ammonium inner salt side groups of approximately 5%.

[0137] Weigh 2.5 g of copolyamide (containing 5% HPCL) and dissolve it in 50 mL of trifluoroethanol. Add 1.00 g of ethylene carbonate and reflux for 24 h. After the reaction is complete, precipitate the solution in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the quaternized antibacterial nylon 6 material CP-35 with a yield of 92%, a number-average molecular weight of 24.9 kDa, and a molar content of quaternary ammonium inner salt side groups of approximately 5%.

[0138] Weigh 2.5 g of copolyamide (containing 5% HPCL) and dissolve it in 50 mL of trifluoroethanol. Add 1.20 g of ethoxyphospholene oxide and reflux for 24 h. After the reaction is complete, precipitate the solution in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the quaternized antibacterial nylon 6 material CP-36 with a yield of 91%, a number-average molecular weight of 23.7 kDa, and a molar content of quaternary ammonium inner salt side groups of approximately 5%.

[0139] Comparative Example 1.

[0140] Weigh 40 mmol of caprolactam and 4 mmol of N-benzoylcaprolactam activator in a 25 ml round-bottom flask. After evacuating and replacing the gas at 40 °C for 30 min, add 4 mmol of sodium hydride and react under nitrogen protection in an oil bath at 180 °C for 6 h. Obtain the conventional nylon 6 material CP-37 with a number-average molecular weight of 30.0 kDa.

[0141] Comparative Example 2.

[0142] Weigh 1 mmol of dimethyl-protected amino-caprolactam, 99 mmol of caprolactam, and 5 mmol of N-benzoylcaprolactam activator into a 25 ml round-bottom flask. After purging with gas at 40 °C for 30 min, add 5 mmol of sodium hydride, and react under nitrogen protection in an oil bath at 180 °C for 6 h. Add 100 ml of trifluoroethanol to dissolve the polymer, precipitate it in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the copolymer product with a yield of about 90%. The results of NMR characterization are as follows: 1 H NMR (500 MHz, TFA / DMSO-d6, 5:95, v:v) δ 3.70 - 3.61, 3.13 - 3.02, 2.76 - 2.72, 2.21 - 2.00, 1.81 - 1.18. By comparing the proton integral areas of chemical shifts 3.70 - 3.61 and 2.21 - 2.00, the insertion molar ratio of dimethylamino-cyclic lysine in the obtained copolymer is calculated to be about 0.5%.

[0143] Weigh 2.5 g of the copolyamide (containing 0.5% DMCL) and dissolve it in 50 mL of trifluoroethanol. Add 1.00 g of propiolactone and reflux for 24 h. After the reaction is complete, precipitate the solution in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the quaternized antibacterial nylon 6 material CP-38 with a yield of 90%, a number-average molecular weight of 21.7 kDa, and the molar content of the quaternary inner salt side group is about 0.5%.

[0144] Comparative Example 3.

[0145] Weigh 50 mmol of dimethyl-protected amino-caprolactam, 50 mmol of caprolactam, and 5 mmol of N-benzoylcaprolactam activator into a 25 ml round-bottom flask. After purging with gas at 40 °C for 30 min, add 5 mmol of sodium hydride, and react under nitrogen protection in an oil bath at 180 °C for 6 h. Add 100 ml of trifluoroethanol to dissolve the polymer, precipitate it in a mixed solvent of ethyl acetate / ether, centrifuge, and dry to obtain the copolymer product with a yield of about 90%. The results of NMR characterization are as follows: 1 H NMR (500 MHz, TFA / DMSO-d6, 5:95, v:v) δ 3.70 - 3.61, 3.13 - 3.02, 2.76 - 2.72, 2.21 - 2.00, 1.81 - 1.18. By comparing the proton integral areas of chemical shifts 3.70 - 3.61 and 2.21 - 2.00, the insertion molar ratio of dimethylamino-cyclic lysine in the obtained copolymer is calculated to be about 55%.

[0146] Weigh 2.5 g of copolyamide (containing 45% DMCL), dissolve it in 50 mL of trifluoroethanol, add 10.00 g of propiolactone, and heat under reflux for 24 h. After the reaction is complete, the solution is precipitated in a mixed solvent of ethyl acetate / ether, centrifuged, and dried to obtain the quaternized antibacterial nylon 6 material CP-39 with a yield of 90%, a number-average molecular weight of 27.9 kDa, and a molar content of quaternary inner salt side groups of about 55%.

[0147] The characteristics of the nylon materials in the above examples and comparative examples are summarized in Table 1 as follows.

[0148] Table 1

[0149]

[0150]

[0151] Effect Example 1.

[0152] Antibacterial effect test:

[0153] The antibacterial effect test was carried out with reference to the method of Chinese national standard GB / T 31402-2023, and some conditions were adjusted according to the actual situation. The specific operations are as follows:

[0154] The antibacterial nylon materials prepared in Examples 1-9 and the nylon materials prepared in Comparative Examples 1-3 were respectively pressed into square thin slices of 5 cm×5 cm, sprayed with 75% alcohol and then dried, irradiated under ultraviolet light for 30 min for sterilization treatment, and then 0.4 mL of bacterial liquid with a concentration of 6×10 5 CFU / mL was dropped on the thin slice, covered with a PET film, and cultured at 37℃ for 24 h. The thin slice was rinsed with 10 mL of SCDLP liquid medium to dilute the bacterial liquid, and after gradient dilution, it was mixed with PCA medium respectively, cultured at 37℃ for 48 h, and the colonies in the medium were counted using an automatic colony counter to calculate the bacterial concentration of the bacterial liquid after culture. The conventional nylon material obtained in Comparative Example 1 was used as the control group.

[0155] Figure 2 The comparative photos of the antibacterial effects of the nylon materials prepared from CP-2 in Example 1 and CP-37 in Comparative Example 1 against Staphylococcus aureus are shown, and the dilution ratio is 100 times. The spots shown are the surviving colonies. It can be clearly seen from the figure that compared with the conventional nylon material prepared in Comparative Example 1, the antibacterial nylon material of the present invention has a significant inhibitory effect on Staphylococcus aureus.

[0156] The test bacteria used were Staphylococcus aureus (S. aureus) ATCC6538 and Escherichia coli (E. coli) ATCC25922.

[0157] The calculation formula for the antibacterial rate is as follows:

[0158]

[0159] The test results are shown in Table 2.

[0160] Effect Example 2.

[0161] Mechanical property test:

[0162] The antibacterial nylon materials prepared in Examples 1-9 and the nylon materials prepared in Comparative Examples 1-3 were respectively injection-molded into 5A type specimens (for dimensions, see Chinese national standard GB / T 1040.2-2022), and tensile property tests were carried out. The results are shown in Table 2.

[0163] Table 2

[0164]

[0165]

[0166]

[0167] The test results can prove that the antibacterial nylon 6 material provided by the present invention has a significant antibacterial effect, and its mechanical properties are basically equivalent to or even better than those of conventional nylon materials (Comparative Example 1). In contrast, due to the too low insertion molar ratio of cyclic lysine, the nylon material in Comparative Example 2 has insufficient antibacterial performance; when the insertion molar ratio is too high, the nylon material in Comparative Example 3 has poor mechanical properties.

[0168] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0169] In addition, it should be noted that, among the various specific technical features described in the above specific embodiments, they can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0170] In addition, any combination can be made between various different embodiments of the present invention, as long as it does not violate the idea of the present invention, and it should also be regarded as the content protected by the present invention.

Claims

1. An antibacterial nylon 6 material, characterized in that, It has the structure shown in the following formula (I): Wherein, each R1 group and each R2 group are independently selected from C 1～24 linear / branched aliphatic hydrocarbon group, substituted / unsubstituted C 3～12 alicyclic hydrocarbon group, substituted / unsubstituted C 6～18 aryl group, substituted / unsubstituted C 7～30 aralkyl group, or the R1 and R2 groups on the same N atom together with the connected N atom form a 5- to 7-membered saturated / unsaturated heterocycle; Each E - group independently selects one or more of the following anion structural general formulas (II): Among them represents a bonding site; each R3 group is independently selected from C 1～24 linear / branched aliphatic hydrocarbon group, substituted / unsubstituted C 3～12 alicyclic hydrocarbon group, substituted / unsubstituted C 6～18 aryl group, substituted / unsubstituted C 7～30 one of aralkyl groups; x is any integer selected from 1 to 18; m = 0.01 - 0.50, n = 0.50 - 0.99, and m + n = 1; The substitution means that the group is substituted by one or more substituents, and the substituents are C 1～18 linear or branched alkyl groups.

2. The antibacterial nylon 6 material according to claim 1, wherein Each R1 group and R2 group are independently selected from C 1～12 a linear / branched aliphatic hydrocarbon group, a substituted / unsubstituted C 3～6 alicyclic hydrocarbon group, a substituted / unsubstituted C 6～10 aryl group, a substituted / unsubstituted C 7～16 aralkyl group, or the R1 and R2 groups on the same N atom together with the connected N atom form a 5- to 6-membered saturated / unsaturated heterocycle; Each R3 group is independently selected from C 1～12 a linear / branched aliphatic hydrocarbon group, a substituted / unsubstituted C 3～6 alicyclic hydrocarbon group, a substituted / unsubstituted C 6～10 aryl group, a substituted / unsubstituted C 7～16 aralkyl group.

3. The antibacterial nylon 6 material according to claim 1, characterized in that, Each R1 group and R2 group are independently selected from one of methyl, ethyl, propyl, butyl, hexyl, octyl, dodecyl, allyl, phenyl, benzyl, or the R1 and R2 groups on the same N atom together with the connected N atom form a pyrrolidinyl group or a piperidinyl group; Each R3 group is independently selected from one of methyl, ethyl, propyl, butyl, hexyl, octyl, dodecyl, cyclohexyl, phenyl, benzyl.

4. A method for preparing the antibacterial nylon 6 material according to any one of claims 1 to 3, characterized in that, It includes the following steps: S1. React 6 - aminocaprolactam shown in the structural formula (Ⅲ) with one or more of aldehydes and / or halogenated hydrocarbons having R1 and / or R2 groups to obtain a cyclic lysine monomer shown in the following formula (Ⅳ): S2. Carry out ring - opening polymerization reaction on the cyclic lysine monomer and caprolactam monomer in a molar ratio of 1:1 - 99 under the action of a catalyst and an activator to obtain a copolymer shown in the following formula (V): S3. React the copolymer with an electrophilic reagent having a heterocycle shown in the following formula (Ⅵ), and the reaction product is sedimented, centrifuged and dried in ethyl acetate / ether to obtain the antibacterial nylon 6 material:

5. The preparation method of the antibacterial nylon 6 material according to claim 4, characterized in that, The catalyst in step S2 is selected from one or more of carbene reagents, guanidine reagents, amidine reagents, phosphazene reagents, alkali metals, alkali metal oxides, alkali metal hydroxides, alkali metal hydrides, alkali metal alkoxides, alkaline earth metals, alkaline earth metal oxides, alkaline earth metal hydroxides, alkaline earth metal hydrides, alkaline earth metal alkoxides.

6. The preparation method of the antibacterial nylon 6 material according to claim 4, characterized in that, The activator in step S2 has the structure shown in the following formula (Ⅶ): Wherein, R4 is selected from one of methyl, ethyl, phenyl, tert - butylphenyl, trifluoromethylphenyl.

7. The preparation method of the antibacterial nylon 6 material according to claim 4, wherein, The total amount of the cyclic lysine monomer and caprolactam monomer, and the molar ratio of the catalyst to the activator is (10 - 50):1:1; the reaction conditions of the ring - opening polymerization reaction in step S2 are: the reaction temperature is 140 - 180 °C, and the reaction time is 3 - 6 h.

8. The preparation method of the antibacterial nylon 6 material according to claim 4, characterized in that, The electrophilic reagent in step S3 is selected from one or several of propiolactone, 1,3 - propane sultone, ethylene carbonate, ethoxyphospholane - 2 - one.

9. The preparation method of the antibacterial nylon 6 material according to claim 4, characterized in that, The reaction in step S3 is carried out in one or more of solvents methanol, ethanol, isopropanol, n - butanol, trifluoroethanol, hexafluoroisopropanol, perfluorotert - butanol, benzyl alcohol, ethylene glycol, cyclohexanol; the reaction conditions of the reaction are: the reaction temperature is 40 - 70 °C, and the reaction time is 10 - 12 h.

10. Use of the antibacterial nylon 6 material according to any one of claims 1-3, characterized in that, It is applied to the preparation of textiles, daily necessities, building materials, packaging materials or panels.

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