Antibacterial nylon material as well as preparation method and application thereof

Abstract

The invention discloses an antibacterial nylon material as well as a preparation method and application thereof, and relates to the technical field of antibacterial high polymer materials.Firstly, a seven-membered cyclic lysine derivative monomer with a quaternary ammonium salt antibacterial group is obtained through lysine cyclization and functionalization; and realizing ring-opening copolymerization of quaternized cyclic lysine and a lactam monomer by using a novel catalytic system, and directly introducing a quaternary ammonium salt group into a side chain of copolyamide. Compared with the prior art, the novel catalytic system constructed by the method disclosed by the invention can directly realize ring-opening copolymerization of quaternization monomers, so that the working procedure of dissolving copolyamide with a solvent and then carrying out quaternization reaction is avoided; the preparation method is simple in process, high in production efficiency, low in cost and suitable for industrial production of the antibacterial nylon material, and an antibacterial agent is not required to be added, and complex operations such as melt blending are avoided. The material has a broad-spectrum, efficient and lasting antibacterial effect, can be formed by injection molding, blow molding, extrusion molding, spinning and the like, and can be widely applied to the fields of fabrics, plates, pipes, packaging, various panels and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of antibacterial polymer materials, and in particular relates to an antibacterial nylon material and a preparation method and application thereof. Background Art

[0002] Nylon (polyamide, PA), the first of the five major engineering plastics, is a long-chain polymer composed of repeating amide groups. It exhibits excellent mechanical properties, wear resistance, self-lubrication, and chemical stability. It has been widely used in personal care, textiles, automobiles, engineering plastics, and packaging, and is ubiquitous in our daily lives. However, traditional nylon materials lack antibacterial properties, making them susceptible to bacterial growth during storage and use, posing a threat to human life and property. Therefore, the development of new antibacterial nylon materials remains of great significance.

[0003] Currently commercialized antimicrobial nylon materials are primarily produced by melt-blending small molecule antimicrobial agents (such as copper ions and silver ions) with nylon. During use, the small molecule antimicrobial agents in these antimicrobial nylon materials easily migrate and dissipate, resulting in poorly sustained antimicrobial performance. Furthermore, these migrated small molecule antimicrobial agents can accumulate through skin contact or the food chain, potentially endangering human health, or enter the environment and cause environmental pollution. This presents numerous challenges regarding the durability, safety, and environmental friendliness of these antimicrobial materials.

[0004] Lysine is a natural renewable resource with abundant production and low price. A seven-membered cyclic lysine monomer can be obtained by lysine cyclization, which has the same cyclic structure as caprolactam. The copolymerization of the two provides a unique idea for the preparation of new antibacterial nylon materials. The document ACS Macro Lett.2022,11,46-52 and the Chinese patent document CN115707727A both report a method for obtaining a new antibacterial nylon 6 material by ring-opening copolymerization of cyclic lysine monomer and caprolactam, introducing a dimethylamine group into the nylon side chain, and further using a halogenated alkane for quaternization reaction. However, in this method, after the copolymerization is completed, expensive and moderately toxic trifluoroethanol must be used as a solvent. The quaternization reaction can only be carried out after the copolyamide is dissolved by long-term stirring, which greatly increases the production cost and the complexity of the preparation process and reduces production efficiency. If the cyclic lysine monomer can be quaternized first and then the ring-opening copolymerization is carried out, the above problems will be effectively solved. However, the use of ordinary catalysts usually requires a higher polymerization temperature, and the quaternary ammonium salt group is prone to Hofmann elimination reaction at high temperatures, making it difficult to exist stably and unable to polymerize. Summary of the Invention

[0005] In order to solve the problems of existing antibacterial nylon materials prepared by melt blending of small molecule antibacterial agents in terms of antibacterial durability, safety, and environmental friendliness, as well as the difficulties in industrial production of antibacterial nylon materials prepared by copolymerization of cyclic lysine and caprolactam, the present invention proposes an antibacterial nylon material, a preparation method and application thereof.

[0006] The technical solutions of the present invention are as follows:

[0007] A method for preparing an antibacterial nylon material comprises the following steps:

[0008] Step 1: mixing a raw material containing lysine with a solvent, and performing a dehydration cyclization reaction at 100° C. to 250° C. to obtain aminocaprolactam;

[0009] Step 2: The primary amine of the aminocaprolactam side chain is first reacted with the corresponding aldehyde and / or halogenated hydrocarbon compound containing the R1 group and / or R2 group, and then reacted with the halogenated alkane containing the R group to obtain a seven-membered cyclic lysine derivative monomer having the following structure:

[0010]

[0011] Wherein, R1 group and R2 group are each independently selected from substituted / unsubstituted linear / branched C 1～20 Aliphatic hydrocarbon, substituted / unsubstituted C 3～12 Any of alicyclic hydrocarbon groups, substituted / unsubstituted aryl groups, substituted / unsubstituted aralkyl groups, or R1 and R2 groups on the same nitrogen atom together with the connected nitrogen atom form a 5-7 membered saturated / unsaturated heterocyclic ring; R group is selected from substituted / unsubstituted linear / branched C 1～20 Aliphatic hydrocarbon, substituted / unsubstituted C 3～12 Any one of an alicyclic hydrocarbon group, a substituted / unsubstituted aryl group, and a substituted / unsubstituted aralkyl group;

[0012] Step 3: adding the seven-membered cyclic lysine derivative monomer and the lactam monomer into a polymerization kettle, adding a two-component catalyst system consisting of a strong base and urea / thiourea and an activator, and performing anionic ring-opening copolymerization at a certain temperature. After completion, washing with a solvent and drying, an antibacterial nylon material is obtained;

[0013] Among them, strong bases can efficiently extract protons from monomers to generate lactam anions to initiate polymerization; urea / thiourea can fully activate lactam monomers, reduce the reaction activation energy, achieve ring-opening copolymerization under mild conditions, and avoid the Hofmann elimination reaction of quaternary ammonium groups in monomers caused by high temperatures;

[0014] The structural formula of the activator is as follows:

[0015]

[0016] Wherein R3 is a substituted or unsubstituted straight chain or branched C 1-5 The aliphatic hydrocarbon group and the substituted or unsubstituted aryl group are more preferably one of methyl, ethyl, phenyl, tert-butylphenyl, p-methoxyphenyl, pentafluorophenyl and trifluoromethylphenyl.

[0017] Preferably, the raw material containing lysine is lysine, a lysine salt or an aqueous solution containing lysine.

[0018] Preferably, the structural formula of the lactam monomer is as follows:

[0019]

[0020] Wherein, n is any natural number selected from 1 to 8.

[0021] Preferably, the strong base is selected from one of 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, carbene reagents, guanidine reagents, amidine reagents, and phosphazene reagents;

[0022] Preferably, the strong base is selected from one of sodium, potassium, sodium hydride, potassium hydride, sodium methoxide, potassium methoxide, potassium tert-butoxide, nitrogen heterocyclic carbamate, organic phosphazene base (t-BuP4, t-BuP2, t-BuP1), TBD, DBU, LiHMDS, and KHMDS.

[0023] Preferably, the structural formula of the urea / thiourea is as follows:

[0024]

[0025] Wherein, X is oxygen or sulfur; R4 and R5 are independently selected from any one of cyclohexyl, phenyl, 3,5-bistrifluoromethylphenyl, and monotrifluoromethyl substituted phenyl.

[0026] Preferably, the molar feed ratio of the seven-membered cyclic lysine derivative monomer to the other lactam monomers in step 2 is 0.01 to 1:1; the ratio of the total molar amount of the seven-membered cyclic lysine derivative monomer and the other lactam monomers to the molar amount of the strong base, the molar amount of urea / thiourea, and the molar amount of the activator in the catalytic system is 100:0.1 to 5:0.1 to 5:0.1 to 5; the polymerization temperature is 80 to 140°C, and the polymerization time is 1 to 24 hours.

[0027] Preferably, the solvent is selected from one or more of water, methanol, ethanol, dichloromethane, acetone, and ethyl acetate; the washing time is 0.1 h to 24 h, and the washing temperature is 25° C. to 100° C.

[0028] The present invention also provides an antibacterial nylon material, which is prepared using the above-mentioned method for preparing the antibacterial nylon material. The structural formula of the antibacterial nylon material is as follows:

[0029]

[0030] Wherein, x and y represent the molar ratio of each part of the repeating unit respectively, x is selected from 0.01 to 0.50, y is selected from 0.50 to 0.99, and x+y=1.

[0031] The present invention also provides an application of the antibacterial nylon material, which is applied to the preparation of fabrics, plates, pipes, packaging or panels.

[0032] Compared with the prior art, the present invention has the following specific beneficial effects:

[0033] 1. In response to the problems existing in the existing antibacterial nylon materials prepared by melt blending of small molecule antibacterial agents in terms of antibacterial durability, safety and environmental friendliness, the present invention utilizes a seven-membered cyclic lysine derivative monomer with an antibacterial group to be ring-opened copolymerized with other lactam monomers, and introduces antibacterial groups into the side chains of nylon through covalent bonds, thereby avoiding the migration and loss of antibacterial agents, giving the nylon material long-lasting and efficient antibacterial properties, and improving its safety and environmental friendliness.

[0034] 2. Compared with the existing method of preparing antibacterial nylon 6 by ring-opening copolymerization of a seven-membered cyclic lysine monomer and caprolactam and then quaternization, the present invention constructs a strong base-urea / thiourea two-component catalytic system, which uses a strong base to efficiently capture the protons of the monomer to generate lactam anions to initiate polymerization. The urea / thiourea fully activates the lactam monomer, reduces the reaction activation energy, and achieves ring-opening copolymerization under mild conditions. Quaternary ammonium salt antibacterial groups are directly introduced into the copolyamide side chain without the use of expensive and moderately toxic solvents such as trifluoroethanol, and without the time-consuming copolyamide dissolution operation. The method has the advantages of low production cost, simple operation, high production efficiency, etc., and is suitable for the industrial production of antibacterial nylon materials.

[0035] 3. The antibacterial nylon material provided by the present invention has a broad-spectrum, high-efficiency and long-lasting antibacterial effect, and can be processed and formed through injection molding, blow molding, extrusion, spinning and other processes. It has a wide range of applications in fields where antibacterial effects are required, such as fabrics, plates, pipes, packaging, various panels, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the synthesis route of the antibacterial nylon material in the present invention. DETAILED DESCRIPTION

[0037] Any specific numerical value disclosed herein (including the endpoints of a numerical range) is not limited to the exact value of the numerical value, but should be understood to also include values ​​close to the exact value, such as all possible values ​​within ±5% of the exact value. Moreover, for a disclosed numerical range, any combination of the endpoints of the range, between the endpoints and the specific points in the range, and between the specific points can be used to generate one or more new numerical ranges, and these new numerical ranges should also be considered to be specifically disclosed herein.

[0038] Unless otherwise specified, the terms used herein have the same meaning as commonly understood by those skilled in the art. If a term is defined herein and its definition is different from the commonly understood meaning in the art, the definition herein shall prevail.

[0039] Except for the matters explicitly stated herein, any matters or items not mentioned herein are directly applicable 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 are considered part of the original disclosure or original description of the present invention and should not be considered as new content not disclosed or anticipated herein, unless a person skilled in the art considers that the combination is obviously unreasonable.

[0040] All patent and non-patent literature, including but not limited to textbooks and journal articles, mentioned herein are incorporated by reference in their entirety.

[0041] In order to make the technical solution of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the specification of the present invention. It should be noted that the following embodiments are only used to better understand the technical solution of the present invention and should not be understood as limiting the present invention.

[0042] Example 1.

[0043] (1) Preparation of aminocaprolactam:

[0044] 6 kg of lysine fermentation broth (lysine mass concentration of 60%) and 50 L of methanol were added to a 100 L reactor. The mixture was stirred and reacted at 220° C. for 2 h under a nitrogen atmosphere. After the reaction was completed, the mixture was cooled to room temperature, and the n-butanol was evaporated and recovered. The mixture was recrystallized from ethyl acetate to obtain aminocaprolactam with a yield of 95%. Its purity was 99% according to H-NMR analysis. 1 H NMR (300MHz, D2O) δ3.69-3.72 (dd, 1H), 3.22-3.26 (m, 2H), 1.26-1.99 (m, 6H).

[0045] (2) Preparation of a seven-membered cyclic lysine-derived monomer with a quaternary ammonium salt antibacterial group (in Formula I, R1 and R2 are methyl groups, and R3 is ethyl group):

[0046] 1 mol of aminocaprolactam prepared in step (1) was added to a 20 L reactor, and 2 mol of paraformaldehyde, 6 g of palladium carbon (5%) and 10 L of methanol were added. The mixture was replaced with nitrogen and hydrogen in sequence, and then filled with hydrogen (pressure 3.0 MPa). The mixture was stirred and reacted at 120° C. for 1 h. After the reaction was completed, the mixture was cooled to room temperature, filtered and the palladium carbon was recovered. 2 mol of bromoethane was added to the filtrate, and the mixture was stirred and reacted at 40° C. for 24 h. The reaction solution was concentrated and recrystallized from dichloromethane to obtain a seven-membered cyclic lysine derivative monomer with an antibacterial group. The yield was 85%, and its purity was 96% according to nuclear magnetic hydrogen spectrum analysis. 1 H NMR(300MHz D2O) δ5.99 (s, 1H), 3.46-3.60 (m, 3H), 3.36-3.40 (m, 1H), 3.24-3.33 (m, 7H), 2.55-2.67 (m, 1H), 1.41-1.75 (m, 5H), 1.32-1.37 (t, 3H).

[0047] (3) Preparation of antibacterial nylon materials:

[0048] 5.5 mmol of the seven-membered cyclic lysine derivative monomer prepared in step (2) and 100 mmol of caprolactam were weighed and added to a polymerization reactor. 3.2 mmol of sodium hydride, 3.2 mmol of thiourea (in Formula IV, X is sulfur, R4 and R5 are 3,5-bistrifluoromethylphenyl), and 3.2 mmol of N-benzoyl caprolactam activator were then added. After purging, the reaction was maintained at 140°C under a nitrogen atmosphere for 8 hours. After washing with water and drying, an antibacterial nylon material (structural formula shown in Formula V, R1 and R2 are methyl, and R3 is ethyl) was obtained with a yield of 93%. Nuclear magnetic resonance analysis showed that the molar percentage of the quaternized seven-membered cyclic lysine in the antibacterial nylon material was approximately 5%.

[0049] Example 2.

[0050] 14 mmol of the seven-membered cyclic lysine derivative monomer prepared in step (2) of Example 1 and 100 mmol of caprolactam were weighed and added to a polymerization reactor. 3.4 mmol of sodium hydride, 3.4 mmol of thiourea (in Formula IV, X is sulfur, R4 and R5 are 3,5-bistrifluoromethylphenyl), and 3.4 mmol of N-benzoylcaprolactam activator were then added. After purging, the reaction was maintained at 140°C under a nitrogen atmosphere for 8 hours. After washing with water and drying, an antibacterial nylon material (structural formula shown in Formula V, where R1 and R2 are methyl and R3 is ethyl) was obtained in a yield of 91%. Nuclear magnetic resonance analysis showed that the molar percentage of the quaternized seven-membered cyclic lysine in the antibacterial nylon material was approximately 10%.

[0051] Example 3.

[0052] 20 mmol of the seven-membered cyclic lysine derivative monomer prepared in step (2) of Example 1 and 100 mmol of caprolactam were weighed and added to a polymerization reactor. 3.6 mmol of sodium hydride, 3.6 mmol of thiourea (in Formula IV, X is sulfur, R4 and R5 are 3,5-bistrifluoromethylphenyl), and 3.6 mmol of N-benzoylcaprolactam activator were then added. After purging, the reaction was maintained at 140°C under a nitrogen atmosphere for 8 hours. After washing with water and drying, an antibacterial nylon material (structural formula shown in Formula V, where R1 and R2 are methyl and R3 is ethyl) was obtained in a 90% yield. Nuclear magnetic resonance analysis showed that the molar percentage of the quaternized seven-membered cyclic lysine in the antibacterial nylon material was approximately 15%.

[0053] Example 4.

[0054] 25 mmol of the seven-membered cyclic lysine derivative monomer prepared in step (2) of Example 1 and 100 mmol of caprolactam were weighed and added to a polymerization reactor. 3.8 mmol of sodium hydride, 3.8 mmol of thiourea (in Formula IV, X is sulfur, R4 and R5 are 3,5-bistrifluoromethylphenyl), and 3.8 mmol of N-benzoylcaprolactam activator were then added. After purging, the reaction was maintained at 140°C under a nitrogen atmosphere for 8 hours. After washing with water and drying, an antibacterial nylon material (structural formula shown in Formula V, where R1 and R2 are methyl and R3 is ethyl) was obtained in an 87% yield. Nuclear magnetic resonance analysis showed that the molar percentage of the quaternized seven-membered cyclic lysine in the antibacterial nylon material was approximately 19%.

[0055] Example 5.

[0056] (1) Preparation of aminocaprolactam

[0057] The preparation method is the same as that of step (1) in Example 1

[0058] (2) Preparation of a seven-membered cyclic lysine-derived monomer with a quaternary ammonium salt antibacterial group (in Formula I, R1 and R2 are methyl, and R3 is n-butyl)

[0059] 1 mol of aminocaprolactam prepared in step (1) was added to a 20 L reactor, and 2 mol of paraformaldehyde, 6 g of palladium carbon (5%) and 10 L of methanol were added. The mixture was replaced with nitrogen and hydrogen in sequence, and then filled with hydrogen (pressure 3.0 MPa). The mixture was stirred and reacted at 120° C. for 1 h. After the reaction was completed, the mixture was cooled to room temperature, filtered and the palladium carbon was recovered. 2 mol of n-butane bromide was added to the filtrate, and the mixture was refluxed and stirred for 12 h. The reaction solution was concentrated and washed with ether to obtain a seven-membered cyclic lysine derivative monomer with a quaternary ammonium salt antibacterial group. The yield was 89%, and its purity was 94% according to nuclear magnetic hydrogen spectrum analysis. 1 H NMR(300MHz D2O) δ5.99 (s, 1H), 3.68-3.72 (t, 1H), 3.47-3.55 (m, 1H), 3.36-3.43 (m, 2H), 3.23-3.3 2(m, 7H), 2.61-2.73(m, 1H), 1.34-1.76(m, 7H), 1.18-1.32(m, 2H), 0.86-0.91(t, 3H).

[0060] (3) Preparation of antibacterial nylon materials

[0061] 15 mmol of the seven-membered cyclic lysine derivative monomer prepared in step (2) and 100 mmol of caprolactam were weighed and added to a polymerization reactor. 5.8 mmol of sodium hydride, 5.8 mmol of thiourea (in Formula IV, X is sulfur, R4 and R5 are phenyl groups), and 5.8 mmol of N-benzoyl caprolactam activator were then added. After purging, the reaction was maintained at 130°C under a nitrogen atmosphere for 8 hours. After washing with water and drying, an antibacterial nylon material (structural formula shown in Formula V, R1 and R2 are methyl groups, and R3 is butyl) was obtained in a yield of 92%. Nuclear magnetic resonance analysis showed that the molar percentage of the quaternized seven-membered cyclic lysine in the antibacterial nylon material was approximately 9%.

[0062] Example 6.

[0063] (1) Preparation of aminocaprolactam

[0064] The preparation method is the same as that of step (1) in Example 1

[0065] (2) Preparation of a seven-membered cyclic lysine-derived monomer with a quaternary ammonium salt antibacterial group (in Formula I, R1 and R2 are methyl groups, and R3 is a benzyl group)

[0066] 1 mol of aminocaprolactam prepared in step (1) was added to a 20 L reactor, and 2 mol of paraformaldehyde, 6 g of palladium carbon (5%) and 10 L of methanol were added. After replacement with nitrogen and hydrogen in sequence, hydrogen was introduced (pressure 3.0 MPa). The reaction was stirred at 120 ° C for 1 h. After the reaction was completed, it was cooled to room temperature, filtered and the palladium carbon was recovered. 3 mol of benzyl bromide was added to the filtrate, and the reaction was refluxed and stirred for 36 h. The reaction solution was concentrated and washed with ether to obtain a seven-membered cyclic lysine derivative monomer with a quaternary ammonium salt antibacterial group. The yield was 78%, and its purity was 92% according to nuclear magnetic hydrogen spectrum analysis. 1 H NMR (300MHz DMSO-d6) δ7.21-7.31 (m, 5H) 6.06 (s, 1H), 4.80 (s, 2H), 3.48-3.61 (m, 2H), 3.29-3.38 (m, 7H), 2.56-2.69 (m, 1H), 1.38-1.80 (m, 5H).

[0067] (3) Preparation of antibacterial nylon materials

[0068] 20 mmol of the seven-membered cyclic lysine derivative monomer prepared in step (2) and 100 mmol of caprolactam were weighed and added to a polymerization reactor. 4.8 mmol of sodium hydride, 4.8 mmol of thiourea (in Formula IV, X is sulfur, R4 and R5 are phenyl groups), and 4.8 mmol of N-benzoyl caprolactam activator were then added. After purging, the reaction was maintained at 140°C under a nitrogen atmosphere for 6 hours. After washing with water and drying, an antibacterial nylon material (structural formula shown in Formula V, where R1 and R2 are methyl groups and R3 is benzyl) was obtained in a 90% yield. Nuclear magnetic resonance analysis showed that the molar percentage of the quaternized seven-membered cyclic lysine in the antibacterial nylon material was approximately 14%.

[0069] Example 7.

[0070] (1) Preparation of aminocaprolactam

[0071] The preparation method is the same as that of step (1) in Example 1

[0072] (2) Preparation of a seven-membered cyclic lysine-derived monomer with a quaternary ammonium salt antibacterial group (in Formula I, R1 and R2 are methyl groups, and R3 is methyl group)

[0073] 1 mol of aminocaprolactam prepared in step (1) was added to a round-bottom flask, and 2 L of methanol and 5 mol of iodomethane were added. The reaction was stirred at room temperature for 24 h. The reaction solution was concentrated and recrystallized from dichloromethane to obtain a seven-membered cyclic lysine derivative monomer with a quaternary ammonium salt antibacterial group. The yield was 90%, and its purity was 96% according to H-NMR analysis. 1H NMR (300MHz D2O) 6.00 (s, 1H), 3.45-3.54 (m, 1H), 3.25-3.36 (m, 11H), 2.57-2.69 (m, 1H), 1.38-1.77 (m, 5H).

[0074] (3) Preparation of antibacterial nylon materials

[0075] 15 mmol of the seven-membered cyclic lysine derivative monomer prepared in step (2) and 100 mmol of caprolactam were weighed and added to a polymerization reactor. 5.8 mmol of phosphazene base (t-BuP4), 5.8 mmol of urea (in Formula IV, X is oxygen, R4 and R5 are 3,5-bistrifluoromethylphenyl), and 5.8 mmol of N-benzoyl caprolactam activator were then added. After purging, the reaction was maintained at 130°C under a nitrogen atmosphere for 8 hours. After washing with water and drying, an antibacterial nylon material (structural formula shown in Formula V, R1 and R2 are methyl groups, and R3 is methyl) was obtained with a yield of 95%. Nuclear magnetic resonance analysis showed that the molar percentage of quaternized seven-membered cyclic lysine in the antibacterial nylon material was approximately 12%.

[0076] Example 8.

[0077] (1) Preparation of aminocaprolactam

[0078] The preparation method is the same as that of step (1) in Example 1

[0079] (2) Preparation of a seven-membered cyclic lysine-derived monomer with a quaternary ammonium salt antibacterial group (in Formula I, R1 and R2 are methyl groups, and R3 is an octyl group)

[0080] 1 mol of aminocaprolactam prepared in step (1) was added to a 20 L reactor, and 2 mol of paraformaldehyde, 6 g of palladium carbon (5%) and 10 L of methanol were added. The mixture was replaced with nitrogen and hydrogen in sequence, and then filled with hydrogen (pressure 3.0 MPa). The mixture was stirred and reacted at 120° C. for 1 h. After the reaction was completed, the mixture was cooled to room temperature, filtered and the palladium carbon was recovered. 3 mol of bromooctane was added to the filtrate, and the mixture was refluxed and stirred for 12 h. The reaction solution was concentrated and washed with ether to obtain a seven-membered cyclic lysine derivative monomer with a quaternary ammonium salt antibacterial group. The yield was 75%, and its purity was 93% according to nuclear magnetic hydrogen spectrum analysis. 1 H NMR (300MHz DMSO-d6) 5.98 (s, 1H), 3.24-3.52 (m, 5H), 3.19 (s, 6H), 2.64-2.76 (m, 1H), 1.22-1.84 (m, 17H), 0.85-0.93 (m, 3H).

[0081] (3) Preparation of antibacterial nylon materials

[0082] 20 mmol of the seven-membered cyclic lysine derivative monomer prepared in step (2) and 100 mmol of caprolactam were weighed and added to a polymerization reactor. 4.8 mmol of sodium methoxide, 4.8 mmol of thiourea (in Formula IV, X is sulfur, R4 and R5 are cyclohexyl groups), and 4.8 mmol of N-benzoyl caprolactam activator were then added. After purging, the reaction was maintained at 140°C under a nitrogen atmosphere for 6 hours. After washing with water and drying, an antibacterial nylon material (structural formula shown in Formula V, R1 and R2 are methyl groups, and R3 is octyl group) was obtained in a yield of 93%. Nuclear magnetic resonance analysis showed that the molar percentage of quaternized seven-membered cyclic lysine in the antibacterial nylon material was approximately 12%.

[0083] Example 9.

[0084] (1) Preparation of aminocaprolactam

[0085] The preparation method is the same as that of step (1) in Example 1

[0086] (2) Preparation of a seven-membered cyclic lysine derivative monomer with a quaternary ammonium salt antibacterial group (in Formula I, R1 and R2 are ethyl groups, and R3 is ethyl group)

[0087] 1 mol of aminocaprolactam prepared in step (1) was dissolved in 1.5 L of methanol, 3 mol of potassium carbonate and 5 mol of ethyl bromide were added, and the reaction was refluxed for 24 h. After cooling, the solution was concentrated, dissolved in dichloromethane, washed and concentrated with water, and washed with ether to obtain a seven-membered cyclic lysine derivative monomer with a quaternary ammonium salt antibacterial group. The yield was 80%, and its purity was 95% according to nuclear magnetic resonance spectroscopy analysis. 1 HNMR(300MHz DMSO-d6)6.00(s,1H),3.71-3.81(m,1H),3.60-3.67(m,6H),3.45-3.52(t,1H),3.14-3 .24(m, 1H), 2.42-2.55(m, 1H), 2.07-2.20(m, 1H), 1.40-1.67(m, 4H), 1.32-1.37(m, 9H).

[0088] (3) Preparation of antibacterial nylon materials

[0089] 15 mmol of the seven-membered cyclic lysine derivative monomer prepared in step (2) and 100 mmol of caprolactam were weighed and added to a polymerization reactor. 4.6 mmol of KHMDS, 4.6 mmol of urea (in Formula IV, X is oxygen, R4 and R5 are phenyl groups), and 4.6 mmol of N-benzoyl caprolactam activator were then added. After purging, the reaction was maintained at 140°C under a nitrogen atmosphere for 6 hours. After washing with water and drying, an antibacterial nylon material (structural formula shown in Formula V, where R1 and R2 are ethyl groups and R3 is ethyl) was obtained in a 90% yield. Nuclear magnetic resonance analysis showed that the molar percentage of the quaternized seven-membered cyclic lysine in the antibacterial nylon material was approximately 11%.

[0090] Example 10.

[0091] (1) Preparation of aminocaprolactam

[0092] The preparation method is the same as that of step (1) in Example 1

[0093] (2) Preparation of a seven-membered cyclic lysine-derived monomer with a quaternary ammonium salt antibacterial group (in Formula I, R1 and R2 are octyl groups, and R3 is ethyl)

[0094] 1 mol of aminocaprolactam prepared in step (1) was dissolved in 1.5 L of methanol, 3 mol of potassium carbonate and 3 mol of n-butane bromide were added, and the reaction was refluxed for 12 h. Then, 2 mol of ethyl bromide was added, and the reaction was refluxed for another 12 h. After cooling, the solution was concentrated, dissolved in dichloromethane, washed and concentrated with water, and washed with ether to obtain a seven-membered cyclic lysine derivative monomer with an antibacterial group. The yield was 75%, and its purity was 95% according to H-NMR spectrum analysis. 1 H NMR(300MHz DMSO-d6) 6.01 (s, 1H), 3.66-3.78 (m, 3H), 3.25-3.56 (m, 6H), 2.84-2.98 (m, 1H), 1.73-1.85 (m, 4H), 1.22-1.65 (m, 28H), 0.86-0.92 (m, 6H).

[0095] (3) Preparation of antibacterial nylon materials

[0096] 20 mmol of the seven-membered cyclic lysine derivative monomer prepared in step (2) and 100 mmol of caprolactam were weighed and added to a polymerization reactor. 4.8 mmol of LiHMDS, 4.8 mmol of urea (in Formula IV, X is oxygen, R4 and R5 are cyclohexyl groups), and 4.8 mmol of N-benzoyl caprolactam activator were then added. After purging, the reaction was maintained at 140°C under a nitrogen atmosphere for 6 hours. After washing with water and drying, an antibacterial nylon material (structural formula shown in Formula V, R1 and R2 are octyl groups, and R3 is ethyl) was obtained in an 86% yield. Nuclear magnetic resonance analysis showed that the molar percentage of the quaternized seven-membered cyclic lysine in the antibacterial nylon material was approximately 12%.

[0097] Example 11.

[0098] (1) Preparation of aminocaprolactam:

[0099] The preparation method is the same as that of step (1) in Example 1

[0100] (2) Preparation of a seven-membered cyclic lysine-derived monomer with a quaternary ammonium salt antibacterial group (in Formula I, R1 and R2 are benzyl groups, and R3 is ethyl):

[0101] 1 mol of aminocaprolactam prepared in step (1) was dissolved in 1.5 L of methanol, 2 mol of potassium carbonate and 3 mol of benzyl bromide were added, and the reaction was refluxed for 12 h. Then, 2 mol of ethyl bromide was added, and the reaction was refluxed for another 12 h. After cooling, the solution was concentrated, dissolved in dichloromethane, washed and concentrated with water, and washed with ether to obtain a seven-membered cyclic lysine derivative monomer with an antibacterial group. The yield was 70%, and its purity was 94% according to H-NMR spectrum analysis. 1 H NMR(300MHz DMSO-d6)7.19-7.26(m,10H),5.96(s,1H),5.06(s,4H),3.56-3.69(m,3H),3.19-3.2 3(m, 2H), 2.75-2.86(m, 1H), 1.86-1.87(m, 1H), 1.41-1.66(m, 4H), 1.31-1.36(m, 3H).

[0102] (3) Preparation of antibacterial nylon materials:

[0103] 20 mmol of the seven-membered cyclic lysine derivative monomer prepared in step (2) and 100 mmol of caprolactam were weighed and added to a polymerization reactor. 4.8 mmol of sodium hydride, 4.8 mmol of thiourea (in Formula IV, X is sulfur, R4 and R5 are 3,5-bisfluorophenyl), and 4.8 mmol of N-benzoyl caprolactam activator were then added. After purging, the reaction was maintained at 140°C under a nitrogen atmosphere for 6 hours. After washing with water and drying, an antibacterial nylon material (structural formula shown in Formula V, R1 and R2 are benzyl groups, and R3 is ethyl) was obtained with a yield of 88%. Nuclear magnetic resonance analysis showed that the molar percentage of quaternized seven-membered cyclic lysine in the antibacterial nylon material was approximately 10%.

[0104] Example 12.

[0105] (1) Preparation of aminocaprolactam:

[0106] The preparation method is the same as that of step (1) in Example 1

[0107] (2) Preparation of a seven-membered cyclic lysine-derived monomer with a quaternary ammonium salt antibacterial group (in Formula I, R1, R2 and the nitrogen atom form a hexahydropyridine group, and R3 is an ethyl group):

[0108] 1 mol of aminocaprolactam prepared in step (1) was dissolved in 1.5 L of methanol, 2 mol of potassium carbonate and 1 mol of 1,5-dibromopentane were added, and the reaction was refluxed for 12 h. Then, 2 mol of ethyl bromide was added, and the reaction was refluxed for another 12 h. After cooling, the solution was concentrated, dissolved in dichloromethane, washed and concentrated with water, and washed with ether to obtain a seven-membered cyclic lysine derivative monomer with an antibacterial group. The yield was 72%, and its purity was 94% according to H-NMR spectrum analysis. 1 H NMR(300MHz DMSO-d6)5.98(s, 1H), 4.09-4.17(m, 2H), 3.49-3.64(m, 2H), 3.25-3.40(m, 5H ), 2.66-2.78(m, 1H), 1.79-1.89(m, 4H), 1.41-1.65(m, 7H), 1.30-1.35(m, 3H).

[0109] (3) Preparation of antibacterial nylon materials:

[0110] 20 mmol of the seven-membered cyclic lysine derivative monomer prepared in step (2) and 100 mmol of caprolactam were weighed and added to a polymerization reactor. 4.8 mmol of sodium hydride, 4.8 mmol of thiourea (in Formula IV, X is sulfur, R4 and R5 are 3,5-bisfluorophenyl), and 4.8 mmol of N-benzoyl caprolactam activator were then added. After purging, the reaction was maintained at 140°C under a nitrogen atmosphere for 6 hours. After washing with water and drying, an antibacterial nylon material (structural formula shown in Formula V, where R1, R2 and the nitrogen atom form a hexahydropyridine group and R3 is an ethyl group) was obtained with a yield of 85%. Nuclear magnetic resonance analysis showed that the molar percentage of the quaternized seven-membered cyclic lysine in the antibacterial nylon material was approximately 9%.

[0111] Comparative Example 1.

[0112] 100 mmol of caprolactam was weighed and added to a polymerization reactor. 4.0 mmol of sodium hydride, 4.0 mmol of thiourea (in Formula IV, X is sulfur, R4 and R5 are 3,5-bisfluorophenyl), and 4.0 mmol of N-benzoylcaprolactam activator were also added. After purging, the reaction was maintained at 140°C under a nitrogen atmosphere for 8 hours. After washing with water and drying, standard nylon material was obtained with a yield of 96%.

[0113] Comparative Example 2.

[0114] 0.9 mmol of the seven-membered cyclic lysine derivative monomer prepared in step (2) of Example 1 and 100 mmol of caprolactam were weighed and added to a polymerization reactor. 4.0 mmol of sodium hydride, 4.0 mmol of thiourea (in Formula IV, X is sulfur, R4 and R5 are 3,5-bisfluorophenyl), and 4.0 mmol of N-benzoylcaprolactam activator were then added. After purging, the reaction was maintained at 140°C under a nitrogen atmosphere for 8 hours. After washing with water and drying, an antibacterial nylon material (structural formula shown in Formula V, R1 and R2 are methyl, and R3 is ethyl) was obtained in a yield of 94%. Nuclear magnetic resonance analysis showed that the molar percentage of quaternized seven-membered cyclic lysine in the antibacterial nylon material was approximately 0.8%.

[0115] Comparative Example 3.

[0116] 100 mmol of the seven-membered cyclic lysine derivative monomer prepared in step (2) of Example 1 and 80 mmol of caprolactam were weighed and added to a polymerization reactor. 7.2 mmol of sodium hydride, 7.2 mmol of thiourea (in Formula IV, X is sulfur, R4 and R5 are 3,5-bisfluorophenyl), and 7.2 mmol of N-benzoylcaprolactam activator were then added. After purging, the reaction was maintained at 140°C under a nitrogen atmosphere for 8 hours. After washing with water and drying, an antibacterial nylon material (structural formula shown in Formula V, where R1 and R2 are methyl and R3 is ethyl) was obtained in an 85% yield. Nuclear magnetic resonance analysis showed that the molar percentage of the quaternized seven-membered cyclic lysine in the antibacterial nylon material was approximately 52%.

[0117] Effect example.

[0118] 1. Antibacterial effect test:

[0119] The antibacterial effect test was carried out according to the method of Chinese national standard GB / T 31402-2023, and some conditions were adjusted according to actual conditions. The specific operation was as follows: the antibacterial nylon materials prepared in Examples 1-12 and the nylon materials prepared in Comparative Examples 1-3 were respectively pressed into 5 cm × 5 cm square sheets, sprayed with 75% alcohol and dried, and irradiated under ultraviolet light for 30 minutes for sterilization. Then, a concentration of 6×10 5 0.4 mL of bacterial solution with a CFU / mL was covered with PET film and cultured at 37°C for 24 hours. The bacterial solution was rinsed and diluted with 10 mL of SCDLP liquid culture medium, and then mixed with PCA culture medium after gradient dilution. The culture was cultured at 37°C for 48 hours. The colonies in the culture medium were counted using a fully automatic colony counter to estimate the bacterial concentration of the bacterial solution after culture. The conventional nylon material obtained in Comparative Example 1 was used as the control group. The test bacteria used were Staphylococcus aureus (S. aureus) ATCC6538 and Escherichia coli (E. coli) ATCC25922. The test results are shown in Table 1.

[0120] The antibacterial rate calculation formula is as follows:

[0121]

[0122] 2. Mechanical properties test:

[0123] The antibacterial nylon materials prepared in Examples 1-12 and the nylon materials prepared in Comparative Examples 1-3 were respectively injection molded into 5A-type specimens (with dimensions according to Chinese national standard GB / T 1040.2-2022), and tensile properties were tested. The results are shown in Table 1.

[0124] Table 1

[0125]

[0126] The data in the table above clearly demonstrate that the antibacterial nylon material of the present invention exhibits significant antibacterial efficacy and mechanical properties substantially comparable to those of conventional nylon materials. In contrast, the nylon material of Comparative Example 2 exhibits insufficient antibacterial performance, while the nylon material of Comparative Example 3 exhibits relatively poor mechanical properties. Compared to the conventional nylon material prepared in Comparative Example 1, the antibacterial nylon material of the present invention exhibits significant inhibitory effects against both Staphylococcus aureus and Escherichia coli.

[0127] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0128] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0129] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the spirit of the present invention, they should also be regarded as the content of the present invention.

[0130] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for preparing an antibacterial nylon material, characterized in that: The following steps are involved: Step 1: mixing a raw material containing lysine with a solvent, and performing a dehydration cyclization reaction at 100° C. to 250° C. to obtain aminocaprolactam; Step 2: aminocaprolactam is first reacted with the corresponding aldehyde and / or halogenated hydrocarbon compound containing R1 group and / or R2 group, and then reacted with the halogenated alkane containing R group to obtain a seven-membered cyclic lysine derivative monomer having the following structure: Wherein, R1 group and R2 group are each independently selected from substituted / unsubstituted linear / branched C 1～20 Aliphatic hydrocarbon, substituted / unsubstituted C 3～12 Any of alicyclic hydrocarbon groups, substituted / unsubstituted aryl groups, substituted / unsubstituted aralkyl groups, or R1 and R2 groups on the same nitrogen atom together with the connected nitrogen atom form a 5-7 membered saturated / unsaturated heterocyclic ring; R group is selected from substituted / unsubstituted linear / branched C 1～20 Aliphatic hydrocarbon, substituted / unsubstituted C 3～12 Any one of an alicyclic hydrocarbon group, a substituted / unsubstituted aryl group, and a substituted / unsubstituted aralkyl group; Step 3: adding the seven-membered cyclic lysine derivative monomer and the lactam monomer into a polymerization kettle, adding a two-component catalyst system consisting of a strong base and urea / thiourea and an activator to carry out anionic ring-opening copolymerization, and washing with a solvent and drying after completion to obtain an antibacterial nylon material; The structural formula of the activator is as follows: Wherein R3 is a substituted or unsubstituted straight chain or branched C 1-5 The aliphatic hydrocarbon group and the substituted or unsubstituted aryl group are more preferably one of methyl, ethyl, phenyl, tert-butylphenyl, p-methoxyphenyl, pentafluorophenyl and trifluoromethylphenyl.

2. The method for preparing the antibacterial nylon material according to claim 1, characterized in that: The raw material containing lysine is lysine, lysine salt or an aqueous solution containing lysine.

3. The method for preparing the antibacterial nylon material according to claim 1, characterized in that: The structural formula of the lactam monomer is as follows: Wherein, n is any natural number selected from 1 to 8.

4. The method for preparing the antibacterial nylon material according to claim 1, characterized in that: The strong base is selected from one of 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, carbene reagents, guanidine reagents, amidine reagents, and phosphazene reagents.

5. The method for preparing the antibacterial nylon material according to claim 4, characterized in that: The strong base is selected from one of sodium, potassium, sodium hydride, potassium hydride, sodium methoxide, potassium methoxide, potassium tert-butoxide, nitrogen heterocyclic carbamate, organic phosphazene base (t-BuP4, t-BuP2, t-BuP1), TBD, DBU, LiHMDS, and KHMDS.

6. The method for preparing the antibacterial nylon material according to claim 1, characterized in that: The structural formula of the urea / thiourea is shown below: Wherein, X is oxygen or sulfur; R4 and R5 are independently selected from any one of cyclohexyl, phenyl, 3,5-bistrifluoromethylphenyl, and monotrifluoromethyl substituted phenyl.

7. The method for preparing the antibacterial nylon material according to claim 1, characterized in that: The molar feed ratio of the seven-membered cyclic lysine derivative monomer to the other lactam monomers in step 2 is 0.01 to 1:1; the ratio of the total molar amount of the seven-membered cyclic lysine derivative monomer and the other lactam monomers to the molar amount of the strong base, the molar amount of urea / thiourea, and the molar amount of the activator in the catalytic system is 100:0.1 to 5:0.1 to 5:0.1 to 5; the polymerization temperature is 80 to 140°C, and the polymerization time is 1 to 24 hours.

8. The method for preparing the antibacterial nylon material according to claim 1, characterized in that: The solvent is selected from one or more of water, methanol, ethanol, dichloromethane, acetone, and ethyl acetate; the washing time is 0.1h to 24h, and the washing temperature is 25°C to 100°C.

9. An antibacterial nylon material, characterized in that: The antibacterial nylon material is prepared by the method for preparing the antibacterial nylon material according to any one of claims 1 to 8, and the structural formula of the antibacterial nylon material is as follows: Wherein, x and y represent the molar ratio of each part of the repeating unit respectively, x is selected from 0.01 to 0.50, y is selected from 0.50 to 0.99, and x+y=1.

10. An application of the antibacterial nylon material according to claim 9, characterized in that: Used in the preparation of fabrics, sheets, pipes, packaging or panels.

Images