An antibacterial and aging-resistant PA-based composite masterbatch and its preparation method

Abstract

This invention discloses an antibacterial and aging-resistant PA-based composite masterbatch and its preparation method, belonging to the field of masterbatch preparation technology. It addresses the technical problem that the comprehensive adaptability of existing PA-based composite masterbatches to various factors such as wear, surface damage, bio-erosion, and corrosive environments needs further improvement during subsequent product preparation and use. This invention introduces amidated triazine powder, zinc-silicon-silver antibacterial powder, and phosphazene-phosphotungstic acid composite powder during masterbatch preparation, and synergistically controls their dispersion state and structural construction, enabling the resulting PA-based composite masterbatch to form a stable composite structure system during subsequent processing and molding. The resulting boards exhibit a coordinated improvement in wear resistance, scratch resistance, antibacterial and antifungal properties, and corrosion resistance, making them suitable for various working conditions.

Description

Technical Field

[0001] This invention relates to the field of masterbatch preparation technology, specifically to an antibacterial and aging-resistant PA-based composite masterbatch and its preparation method. Background Technology

[0002] In recent years, PA engineering plastics have been widely used in sheet materials and structural components in fields such as building decoration, public facilities, transportation, and industrial equipment due to their good mechanical properties, heat resistance, and processing adaptability. With the increasing complexity of application environments, related products are often affected by humid and hot conditions, chemical media, and corrosive environments during service. During long-term use, the materials are prone to changes in properties related to corrosion aging, which affects their structural stability and service life. At the same time, the attention to the surface hygiene performance of materials in public environments and high-contact application scenarios is constantly increasing, and antibacterial and antifungal functions are gradually becoming important research directions in the design and modification of PA materials.

[0003] Currently, PA-based composite masterbatches are mostly modified with single or small amounts of functional additives. Their processes focus on improving initial performance indicators. However, during the material preparation and molding process, the dispersion state and structural participation mode of different functional components in the system lack synergistic control. In actual use, when the material is subjected to friction, external force contact or surface scratches, the surface state is prone to change due to local structural differences. The wear resistance fluctuates with the extension of the service time, and micro-defects are also prone to form in the surface area, thus affecting the surface durability of the material.

[0004] Meanwhile, the antibacterial function in traditional processes often relies on surface treatment or unstable antibacterial components. When the material is repeatedly exposed to moisture, pollutants, or in a humid or slightly corrosive environment, its effectiveness is easily affected by changes in the material structure. Furthermore, under long-term environmental conditions, the internal structure of some PA materials is quite sensitive to the response of humid heat or corrosive media, and the performance stability changes with the service time, which limits the reliability and consistency of the material under complex usage conditions. Summary of the Invention

[0005] The purpose of this invention is to provide an antibacterial and aging-resistant PA-based composite masterbatch and its preparation method, which solves the technical problem that the comprehensive adaptability of PA-based composite masterbatches to various factors such as wear, surface damage, bio-erosion and corrosive environment in the subsequent product preparation and use process in the prior art needs to be further improved.

[0006] The objective of this invention can be achieved through the following technical solution: a method for preparing an antibacterial and aging-resistant PA-based composite masterbatch, comprising the following steps:

[0007] Step 1: Using carboxylated triazine covalent framework powder as raw material, the carboxyl group is activated and reacted with an amino-containing compound to introduce a polyamide reactive structure on its surface, thus obtaining amidated triazine powder;

[0008] Step 2: Hydrolysis and condensation are performed using a silicon source as a precursor to form a silicon-oxygen network structure, and a zinc component is introduced to form a zinc-silicon hybrid system. On this basis, a silver component is loaded and its immobilization is achieved to obtain zinc-silicon-silver antibacterial powder.

[0009] Step 3: Using hexachlorocyclotriphosphazene as raw material, an aminosilane structure is introduced through substitution, and it undergoes an ion hybridization reaction with phosphotungstic acid to form phosphazene-phosphotungstic acid composite powder.

[0010] Step 4: Weigh out the following by weight: 60 parts polyamide resin, 8-10 parts amidated triazine powder, 2-3 parts zinc-silicon-silver antibacterial powder, 6-8 parts phosphazene-phosphotungstic acid composite powder, and 2 parts processing aid. Add these to a twin-screw extruder, melt extrude, and granulate to obtain PA-based composite masterbatch.

[0011] The reaction principle for preparing PA-based composite masterbatch is as follows:

[0012] Polyamide resin transforms from a solid state to a continuous molten phase under heating conditions, providing a matrix environment for the dispersion of various inorganic and organic functional powders. The amide groups on the surface of amidated triazine powder and the polyamide molecular chains form a stable interface structure through polar interactions. Zinc-silicon-silver antibacterial powder and phosphazene-phosphotungstic acid composite powder are uniformly embedded in the continuous polyamide phase under melt shearing. The lubricating components, stabilizing components and epoxy structure in the processing aid coexist synergistically in the molten system, thereby constructing a multiphase composite system with polyamide as the continuous phase and various powders as the dispersed phase in the molten state, and finally preparing PA-based composite masterbatch.

[0013] The processing aid is prepared by mixing ethylene bis-stearamide, antioxidant 1098, antioxidant 168 and 1,3,5-triglycidyl-S-triazine trione in a ratio of 1g:0.4g:0.2g:0.4g.

[0014] Furthermore, the twin-screw extruder has six temperature zones of 225℃, 235℃, 240℃, 245℃, 245℃, and 250℃, and a screw speed of 150 rpm.

[0015] Furthermore, the granulation particle size is 2-3 mm and the particle length is 3-5 mm.

[0016] Further, in step one, the preparation method of the amidated triazine powder is as follows: carboxylated triazine covalent framework powder and anhydrous tetrahydrofuran are added to a reaction vessel and stirred. After being evenly dispersed, thionyl chloride and N,N-dimethylformamide are added. Under nitrogen protection, the reaction vessel is heated to 65-75℃ and stirred for 3-5 hours. After the reaction is completed, the reaction vessel is cooled to 0-5℃, 6-aminohexanoic acid and triethylamine are added, and then the temperature is raised to 55-65℃ and stirred for 3-5 hours. The amidated triazine powder is obtained by post-treatment.

[0017] The reaction principle for preparing amidated triazine powder is as follows:

[0018] The carboxyl groups on the surface of the carboxylated triazine covalent framework powder are activated by acyl chloride in the system of thionyl chloride and N,N-dimethylformamide, generating an acyl chloride structure with high reactivity. Subsequently, under alkaline conditions, the amino group in the 6-aminohexanoic acid molecule acts as a nucleophile to attack the carbonyl carbon atom in the acyl chloride functional group, forming a stable amide bond, thereby realizing the covalent grafting of the amino-containing chain segment onto the surface of the triazine covalent framework. Triethylamine is used to capture the acidic substances generated during the reaction and maintain the stability of the reaction system, finally preparing the amidated triazine powder.

[0019] Furthermore, in the preparation of amidated triazine powder, the ratio of the carboxylated triazine covalent framework powder, anhydrous tetrahydrofuran, thionyl chloride, N,N-dimethylformamide, 6-aminohexanoic acid and triethylamine is 6-8g:100mL:12-16mL:0.8mL:5-7g:10mL. The post-treatment includes: filtration after the reaction, washing and drying to obtain amidated triazine powder.

[0020] Furthermore, the carboxylated triazine covalent framework powder is prepared by the following method:

[0021] Step I: Add 2,6-pyridinedicarboxynitrile, terephthalonitrile and zinc chloride to the reaction vessel and mix evenly. Seal the reaction vessel and heat it to 380-420℃. Keep the temperature for 18-22h and then process it to obtain triazine covalent framework matrix powder.

[0022] Step II: Add the triazine covalent framework matrix powder, 65wt% nitric acid aqueous solution and deionized water to the reaction vessel and stir. After the mixture is uniform, heat the reaction vessel to 75-85℃ and keep it at that temperature for 5-7 hours. Post-processing yields carboxylated triazine covalent framework powder.

[0023] The reaction principle for preparing carboxylated triazine covalent framework powder is as follows:

[0024] 2,6-Pyridinedicarboxynitrile and terephthalonitrile undergo a condensation reaction under high-temperature melting conditions and the action of zinc chloride. The nitrile group undergoes cyclization rearrangement in a Lewis acid environment, gradually forming a covalent organic framework with triazine structure as the basic unit. Zinc chloride acts as both a molten salt medium and a structure guide during the reaction, thereby constructing a triazine covalent framework structure with regular framework characteristics. In the subsequent nitric acid system, the strong oxidizing environment acts on the active sites in the framework, causing some aromatic structures to undergo oxidative transformation, introducing oxygen-containing functional groups and forming stable carboxyl-substituted structures. This achieves functionalization modification while maintaining the original covalent framework structure, and finally prepares carboxylated triazine covalent framework powder.

[0025] Furthermore, in step I, the ratio of 2,6-pyridinedicarboxynitrile, terephthalonitrile, and zinc chloride is 10-12g:10g:150g. The post-treatment includes: natural cooling after the reaction is completed, taking out the obtained solid and crushing it through a 100-mesh sieve, washing and drying it to obtain triazine covalent framework matrix powder.

[0026] Furthermore, in step II, the ratio of triazine covalent framework matrix powder, 65wt% nitric acid aqueous solution, and deionized water is 8-10g:60-80mL:40mL. The post-treatment includes: filtration and washing after the reaction, followed by drying to obtain carboxylated triazine covalent framework powder.

[0027] Further, in step two, the preparation method of the zinc-silicon-silver antibacterial powder is as follows: tetraethyl orthosilicate, 3-aminopropyltriethoxysilane, deionized water and anhydrous ethanol are added to a reaction vessel and stirred. After mixing evenly, glacial acetic acid is added and the reaction vessel is heated to 30-35°C. After stirring at this temperature for 1.5-2.5 hours, zinc acetate dihydrate is added and stirred for 40-60 minutes. Then, silver nitrate is added and stirred in the dark for 20-40 minutes. After cooling the reaction vessel to 0-5°C, a reducing agent is added and stirred at this temperature for 30-60 minutes. The zinc-silicon-silver antibacterial powder is then obtained through post-treatment.

[0028] The reaction principle for preparing zinc-silicon-silver antibacterial powder is as follows:

[0029] Tetraethyl orthosilicate undergoes controlled hydrolysis and condensation under acidic conditions to form an inorganic network structure dominated by silicon-oxygen bonds. An amino-containing organosilicon reagent introduces amino coordination sites through co-condensation. Zinc acetate coordinates with the silicon-oxygen framework and amino groups in this system to construct a composite structure involving zinc. Silver ions in silver nitrate are transformed and stabilized in the silicon-oxygen network and coordination structure under a reducing environment, thus forming a composite powder system in which zinc, silicon, and silver coexist, and finally, zinc-silicon-silver antibacterial powder is prepared.

[0030] Furthermore, in the preparation of zinc-silicon-silver antibacterial powder, the ratio of tetraethyl orthosilicate, 3-aminopropyltriethoxysilane, deionized water, anhydrous ethanol, glacial acetic acid, zinc acetate dihydrate, silver nitrate, and reducing agent is 20-24 mL:10 mL:10 mL:100 mL:1 mL:3-5 g:0.8-1.0 g:20-30 mL, wherein the reducing agent is a 1-2 wt% sodium borohydride aqueous solution. The post-treatment includes: after stirring, heating the reaction vessel to 20-30°C, aging and stirring for 1.5-2.5 h, filtering after the reaction, washing and drying to obtain zinc-silicon-silver antibacterial powder.

[0031] Furthermore, in step three, the preparation method of the phosphazene-phosphotungstic acid composite powder is as follows: hexachlorocyclotriphosphazene and anhydrous acetonitrile are added to a reaction vessel and stirred. After complete dissolution, 3-aminopropyltriethoxysilane and triethylamine are added. The reaction vessel is heated to 55-65℃ and stirred for 7-9 hours. After stirring, the reaction vessel is cooled to 20-30℃, a modifier is added, and the mixture is stirred for 1.5-2.5 hours. The phosphazene-phosphotungstic acid composite powder is obtained after post-treatment.

[0032] The reaction principle for preparing phosphazene-phosphotungstic acid composite powder is as follows:

[0033] The P-Cl bond in the hexachlorocyclotriphosphazene molecule has high nucleophilic substitution activity. In organic solvent systems, it can undergo stepwise substitution reactions with amino-containing organosilicon reagents to form an organic-inorganic hybrid system with a phosphazene ring as the backbone and aminopropylsiloxane structures as side links. Triethylamine acts as an acid scavenger to suppress side reactions and stabilize the reaction environment. The introduced phosphotungstic acid combines with the aminophosphazene structure through ionic interactions, thereby constructing a composite system of phosphazene and heteropolyacid coexisting at the molecular scale. Finally, phosphazene-phosphotungstic acid composite powder is prepared.

[0034] Furthermore, in the preparation of phosphazene-phosphotungstic acid composite powder, the ratio of hexachlorocyclotriphosphazene, anhydrous acetonitrile, 3-aminopropyltriethoxysilane, triethylamine, and the modifier is 6-8g:100mL:18-20mL:18-21mL:20-30mL. The modifier is obtained by mixing phosphatungstic acid and anhydrous ethanol at a ratio of 3-5g:20-30mL. The post-treatment includes: filtration after stirring, washing, and drying to obtain phosphazene-phosphotungstic acid composite powder.

[0035] The present invention also discloses an antibacterial and aging-resistant PA-based composite masterbatch, which is prepared by the above-mentioned method for preparing an antibacterial and aging-resistant PA-based composite masterbatch.

[0036] The present invention has the following beneficial effects:

[0037] 1. During the material preparation and molding process, the introduction of amidated triazine powder makes the material exhibit a more stable surface state when subjected to frictional loads. Under long-term use conditions, it is not prone to rapid wear or surface damage. On this basis, the phosphazene-phosphotungstic acid composite powder enhances the overall stability of the material, enabling this wear resistance to be maintained continuously in various usage environments, avoiding performance fluctuations due to structural changes. At the same time, the presence of zinc-silicon-silver antibacterial powder improves the uniformity of the material surface, making it less likely to form local defects when the surface is subjected to external force contact or scratching. The synergistic effect of the above-mentioned multifunctional powders in the same material system enables the material to improve wear resistance while simultaneously improving surface damage resistance, thus exhibiting higher surface durability in actual use.

[0038] 2. During the use of the material, the zinc-silicon-silver antibacterial powder prepared by this invention is uniformly distributed in the near-surface area of ​​the material as a continuous action unit, maintaining a long-term coupling relationship with the material surface contact environment. In actual use, when the material surface is repeatedly exposed to media such as water vapor, pollutants, or human skin, the microbial attachment process is interfered with, and the continuity of surface biofilm formation is interrupted. At the same time, the stabilizing effect of amidated triazine powder on the microstructure of the material restricts the formation of surface micropores and retention sites, thereby reducing the geometric conditions for microbial aggregation. Furthermore, the phosphazene-phosphotungstic acid composite powder plays a buffering role against structural fluctuations in humid and mildly corrosive environments, making the above-mentioned inhibitory effect less susceptible to weakening due to material state drift during environmental changes.

[0039] 3. When the material is exposed to a humid or corrosive environment, the introduction of the phosphazene-phosphotungstic acid composite powder prepared in this invention enables the material to maintain a relatively stable state under the action of the external medium, thereby reducing the impact of environmental factors on the material performance. In this process, the amidated triazine powder enhances the overall structural stability of the material, making it less prone to performance degradation under long-term environmental action and helping to maintain normal performance. At the same time, the zinc-silicon-silver antibacterial powder indirectly improves the service conditions of the material in complex environments by inhibiting microbial-related activities. By utilizing the synergistic effect of multiple functional powders in terms of corrosion resistance and environmental adaptability, the material exhibits high stability and reliability during long-term use. Detailed Implementation

[0040] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] In this application, the polyamide resin used was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., with the product number P723205; the antioxidant 1098 used was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., with the product number N864872; and the antioxidant 168 used was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., with the product number T822863.

[0042] Example 1

[0043] This embodiment provides a method for preparing amidated triazine powder, including the following steps:

[0044] Step 1: Preparation of triazine covalent framework matrix powder

[0045] Weigh out 10.0g of 2,6-pyridinedicarboxynitrile, 10.0g of terephthalonitrile and 150.0g of zinc chloride and add them to the reaction vessel. Mix them evenly, seal the reaction vessel and heat it to 380℃. Keep the temperature for 18h and let it cool naturally after the reaction is complete. Take out the obtained solid and crush it through a 100-mesh sieve. Wash and dry it to obtain triazine covalent framework matrix powder.

[0046] Step 2: Preparation of carboxylated triazine covalent framework powder

[0047] Weigh out 8.0 g of triazine covalent framework matrix powder, 60.0 mL of 65 wt% nitric acid aqueous solution and 40.0 mL of deionized water and add them to the reaction vessel. Stir until the mixture is homogeneous, then heat the reaction vessel to 75 °C and keep it at that temperature for 5 h. After the reaction is complete, filter, wash and dry to obtain carboxylated triazine covalent framework powder.

[0048] Step 3: Preparation of amidated triazine powder

[0049] Weigh 6.0 g of carboxylated triazine covalent framework powder and 100.0 mL of anhydrous tetrahydrofuran and add them to a reaction vessel. Stir until the mixture is evenly dispersed. Then add 12.0 mL of thionyl chloride and 0.8 mL of N,N-dimethylformamide. Under nitrogen protection, heat the reaction vessel to 65 °C and stir for 3 h. After the reaction is complete, cool the reaction vessel to 0 °C and add 5.0 g of 6-aminohexanoic acid and 10.0 mL of triethylamine. Then heat the mixture to 55 °C and stir for 3 h. After the reaction is complete, filter, wash and dry to obtain amidated triazine powder.

[0050] Example 2

[0051] This embodiment provides a method for preparing amidated triazine powder, including the following steps:

[0052] Step 1: Preparation of triazine covalent framework matrix powder

[0053] Weigh out 12.0g of 2,6-pyridinedicarboxynitrile, 10.0g of terephthalonitrile and 150.0g of zinc chloride and add them to the reaction vessel. Mix them evenly, seal the reaction vessel and heat it to 420℃. Keep the temperature for 22h and allow it to cool naturally after the reaction is complete. Take out the obtained solid and crush it through a 100-mesh sieve. Wash and dry it to obtain triazine covalent framework matrix powder.

[0054] Step 2: Preparation of carboxylated triazine covalent framework powder

[0055] Weigh out 10.0g of triazine covalent framework matrix powder, 80.0mL of 65wt% nitric acid aqueous solution and 40.0mL of deionized water and add them to the reaction vessel. Stir until the mixture is homogeneous, then heat the reaction vessel to 85℃ and keep it at that temperature for 7h. After the reaction is complete, filter, wash and dry to obtain carboxylated triazine covalent framework powder.

[0056] Step 3: Preparation of amidated triazine powder

[0057] Weigh 8.0 g of carboxylated triazine covalent framework powder and 100.0 mL of anhydrous tetrahydrofuran and add them to a reaction vessel. Stir until the mixture is evenly dispersed. Then add 16.0 mL of thionyl chloride and 0.8 mL of N,N-dimethylformamide. Under nitrogen protection, heat the reaction vessel to 75 °C and stir for 5 h. After the reaction is complete, cool the reaction vessel to 5 °C and add 7.0 g of 6-aminohexanoic acid and 10.0 mL of triethylamine. Then heat the mixture to 65 °C and stir for 5 h. After the reaction is complete, filter, wash and dry to obtain amidated triazine powder.

[0058] Example 3

[0059] This embodiment provides a method for preparing amidated triazine powder, including the following steps:

[0060] Step 1: Preparation of triazine covalent framework matrix powder

[0061] Weigh out 11.0g of 2,6-pyridinedicarboxynitrile, 10.0g of terephthalonitrile and 150.0g of zinc chloride and add them to the reaction vessel. Mix them evenly, seal the reaction vessel and heat it to 400℃. Keep the temperature for 20h and let it cool naturally after the reaction is complete. Take out the obtained solid and crush it through a 100-mesh sieve. Wash and dry it to obtain triazine covalent framework matrix powder.

[0062] Step 2: Preparation of carboxylated triazine covalent framework powder

[0063] Weigh out 9.0 g of triazine covalent framework matrix powder, 70.0 mL of 65 wt% nitric acid aqueous solution and 40.0 mL of deionized water and add them to the reaction vessel. Stir until the mixture is uniform, then heat the reaction vessel to 80 °C and keep it at that temperature for 6 h. After the reaction is complete, filter, wash and dry to obtain carboxylated triazine covalent framework powder.

[0064] Step 3: Preparation of amidated triazine powder

[0065] Weigh 7.0 g of carboxylated triazine covalent framework powder and 100.0 mL of anhydrous tetrahydrofuran and add them to a reaction vessel. Stir until the mixture is evenly dispersed. Then add 14.0 mL of thionyl chloride and 0.8 mL of N,N-dimethylformamide. Under nitrogen protection, heat the reaction vessel to 70 °C and stir for 4 h. After the reaction is complete, cool the reaction vessel to 3 °C and add 6.0 g of 6-aminohexanoic acid and 10.0 mL of triethylamine. Then heat the mixture to 60 °C and stir for 4 h. After the reaction is complete, filter, wash and dry to obtain amidated triazine powder.

[0066] Example 4

[0067] This embodiment provides a method for preparing an antibacterial and aging-resistant PA-based composite masterbatch, including the following steps:

[0068] Step S1: Preparation of zinc-silicon-silver antibacterial powder

[0069] Weigh out 20.0 mL of tetraethyl orthosilicate, 10.0 mL of 3-aminopropyltriethoxysilane, 10.0 mL of deionized water, and 100.0 mL of anhydrous ethanol and add them to a reaction vessel. Stir until the mixture is homogeneous, then add 1.0 mL of glacial acetic acid and heat the reaction vessel to 30°C. Keep the mixture warm and stir for 1.5 h. Add 3.0 g of zinc acetate dihydrate and stir for 40 min. Then add 0.8 g of silver nitrate and stir in the dark for 20 min. Cool the reaction vessel to 0°C and add 20.0 mL of 1 wt% sodium borohydride aqueous solution. Keep the mixture warm and stir for 30 min. After stirring, heat the reaction vessel to 20°C and age and stir for 1.5 h. After the reaction is complete, filter, wash, and dry to obtain zinc-silicon-silver antibacterial powder.

[0070] Step S2: Preparation of phosphazene-phosphotungstic acid composite powder

[0071] Weigh out 3.0 g of phosphotungstic acid and mix it with 20.0 mL of anhydrous ethanol to obtain the modifier;

[0072] Weigh 6.0 g of hexachlorocyclotriphosphazene and 100.0 mL of anhydrous acetonitrile and add them to the reaction vessel. Stir until completely dissolved. Then add 18.0 mL of 3-aminopropyltriethoxysilane and 18.0 mL of triethylamine. Heat the reaction vessel to 55 °C and keep it at that temperature for 7 h. After stirring, cool the reaction vessel to 20 °C and add 20.0 mL of the modifier. Stir for 1.5 h. After stirring, filter, wash and dry to obtain phosphazene-phosphotungstic acid composite powder.

[0073] Step S3: Preparation of PA-based composite masterbatch

[0074] Weigh out 2.0g of ethylene bis-stearamide, 0.8g of antioxidant 1098, 0.4g of antioxidant 168 and 0.8g of 1,3,5-triglycidyl-S-triazine trione and mix them to obtain a processing aid;

[0075] By weight, 60 parts of polyamide resin, 8 parts of amidated triazine powder prepared in Example 1, 2 parts of zinc-silicon-silver antibacterial powder, 6 parts of phosphazene-phosphotungstic acid composite powder, and 2 parts of processing aid were weighed and added to a twin-screw extruder. The six temperature zones of the twin-screw extruder were 225°C, 235°C, 240°C, 245°C, 245°C, and 250°C, and the screw speed was 150 rpm. The mixture was melt-extruded and granulated to obtain PA-based composite masterbatch with a particle size of 2 mm and a particle length of 3 mm.

[0076] Example 5

[0077] This embodiment provides a method for preparing an antibacterial and aging-resistant PA-based composite masterbatch, including the following steps:

[0078] Step S1: Preparation of zinc-silicon-silver antibacterial powder

[0079] Weigh out 24.0 mL of tetraethyl orthosilicate, 10.0 mL of 3-aminopropyltriethoxysilane, 10.0 mL of deionized water, and 100.0 mL of anhydrous ethanol and add them to a reaction vessel. Stir until the mixture is homogeneous, then add 1.0 mL of glacial acetic acid and heat the reaction vessel to 35°C. Keep the mixture warm and stir for 2.5 h. Add 5.0 g of zinc acetate dihydrate and stir for 60 min. Then add 1.0 g of silver nitrate and stir in the dark for 40 min. Cool the reaction vessel to 5°C and add 30.0 mL of 2 wt% sodium borohydride aqueous solution. Keep the mixture warm and stir for 60 min. After stirring, heat the reaction vessel to 30°C and age and stir for 2.5 h. After the reaction is complete, filter, wash, and dry to obtain zinc-silicon-silver antibacterial powder.

[0080] Step S2: Preparation of phosphazene-phosphotungstic acid composite powder

[0081] Weigh out 5.0 g of phosphotungstic acid and mix it with 30.0 mL of anhydrous ethanol to obtain the modifier;

[0082] Weigh 8.0 g of hexachlorocyclotriphosphazene and 100.0 mL of anhydrous acetonitrile and add them to the reaction vessel. Stir until completely dissolved, then add 20.0 mL of 3-aminopropyltriethoxysilane and 21.0 mL of triethylamine. Heat the reaction vessel to 65 °C and keep it at that temperature for 9 h. After stirring, cool the reaction vessel to 30 °C, add 30.0 mL of the modifier, and stir for 2.5 h. After stirring, filter, wash and dry to obtain phosphazene-phosphotungstic acid composite powder.

[0083] Step S3: Preparation of PA-based composite masterbatch

[0084] Weigh out 2.0g of ethylene bis-stearamide, 0.8g of antioxidant 1098, 0.4g of antioxidant 168 and 0.8g of 1,3,5-triglycidyl-S-triazine trione and mix them to obtain a processing aid;

[0085] By weight, 60 parts of polyamide resin, 10 parts of amidated triazine powder prepared in Example 2, 3 parts of zinc-silicon-silver antibacterial powder, 8 parts of phosphazene-phosphotungstic acid composite powder, and 2 parts of processing aid were weighed and added to a twin-screw extruder. The six temperature zones of the twin-screw extruder were 225°C, 235°C, 240°C, 245°C, 245°C, and 250°C, and the screw speed was 150 rpm. The mixture was melt-extruded and granulated to obtain PA-based composite masterbatch with a particle size of 3 mm and a particle length of 5 mm.

[0086] Example 6

[0087] This embodiment provides a method for preparing an antibacterial and aging-resistant PA-based composite masterbatch, including the following steps:

[0088] Step S1: Preparation of zinc-silicon-silver antibacterial powder

[0089] Weigh out 21.0 mL of tetraethyl orthosilicate, 10.0 mL of 3-aminopropyltriethoxysilane, 10.0 mL of deionized water, and 100.0 mL of anhydrous ethanol and add them to a reaction vessel. Stir until the mixture is homogeneous, then add 1.0 mL of glacial acetic acid and heat the reaction vessel to 35°C. Keep the mixture warm and stir for 2.0 h. Add 4.0 g of zinc acetate dihydrate and stir for 50 min. Then add 0.9 g of silver nitrate and stir in the dark for 30 min. Cool the reaction vessel to 3°C and add 25.0 mL of 2wt% sodium borohydride aqueous solution. Keep the mixture warm and stir for 45 min. After stirring, heat the reaction vessel to 25°C and age and stir for 2.0 h. After the reaction is complete, filter, wash, and dry to obtain zinc-silicon-silver antibacterial powder.

[0090] Step S2: Preparation of phosphazene-phosphotungstic acid composite powder

[0091] Weigh out 4.0 g of phosphotungstic acid and mix it with 25.0 mL of anhydrous ethanol to obtain the modifier;

[0092] Weigh 7.0 g of hexachlorocyclotriphosphazene and 100.0 mL of anhydrous acetonitrile and add them to the reaction vessel. Stir until completely dissolved, then add 19.0 mL of 3-aminopropyltriethoxysilane and 20.0 mL of triethylamine. Heat the reaction vessel to 60 °C and keep it at that temperature for 8 h. After stirring, cool the reaction vessel to 25 °C, add 25.0 mL of the modifier, and stir for 2.0 h. After stirring, filter, wash and dry to obtain phosphazene-phosphotungstic acid composite powder.

[0093] Step S3: Preparation of PA-based composite masterbatch

[0094] Weigh out 2.0g of ethylene bis-stearamide, 0.8g of antioxidant 1098, 0.4g of antioxidant 168 and 0.8g of 1,3,5-triglycidyl-S-triazine trione and mix them to obtain a processing aid;

[0095] By weight, 60 parts of polyamide resin, 9 parts of amidated triazine powder prepared in Example 3, 3 parts of zinc-silicon-silver antibacterial powder, 7 parts of phosphazene-phosphotungstic acid composite powder and 2 parts of processing aid were weighed and added to a twin-screw extruder. The six temperature zones of the twin-screw extruder were 225℃, 235℃, 240℃, 245℃, 245℃ and 250℃, and the screw speed was 150 rpm. The mixture was melt-extruded and granulated to obtain PA-based composite masterbatch with a particle size of 2 mm and a particle length of 4 mm.

[0096] Comparative Example 1

[0097] The difference between this comparative example and Example 6 is that, in the preparation process of the amidated triazine powder used in step S3, step (3) is omitted, and the carboxylated triazine covalent framework powder prepared in step (2) is used to replace the amidated triazine powder in an equal amount.

[0098] Comparative Example 2

[0099] The difference between this comparison and Example 6 is that the zinc-silicon-silver antibacterial powder is omitted in step S3.

[0100] Comparative Example 3

[0101] The difference between this comparison and Example 6 is that the phosphazene-phosphotungstic acid composite powder is omitted in step S3.

[0102] Performance testing:

[0103] By weight, 90 parts of polyamide resin and 10 parts of PA-based composite masterbatch prepared in Examples 4-6 and Comparative Examples 1-3 were weighed and mixed evenly. After drying at 85°C for 8 hours, the mixture was added to an extruder for melt plasticizing and extrusion. The temperatures of the six zones of the extruder were 225°C, 235°C, 240°C, 245°C, 245°C, and 250°C, respectively. The die temperature was 250°C, and the screw speed was 120 rpm. The melt was extruded into sheets through a T-die and then calendered to a fixed thickness using a three-roll calender. The temperatures of the three rolls were 80°C, 70°C, and 50°C, respectively. After cooling and traction, the sheets were cut to length to obtain artificial boards with a thickness of 4 mm, a width of 600 mm, and a length of 1200 mm. Artificial boards were also prepared using polyamide resin alone in the same process, which was recorded as a blank control group.

[0104] The mass abrasion of the artificial boards prepared in the blank control group and the artificial boards prepared using PA-based composite masterbatches prepared in Examples 4-6 and Comparative Examples 1-3 were tested in accordance with the standard GB / T 5478-2008 "Test Method for Rolling Abrasion of Plastics".

[0105] The scratch resistance ratings of engineered wood panels prepared in the blank control group and engineered wood panels prepared using PA-based composite masterbatches prepared in Examples 4-6 and Comparative Examples 1-3 were determined in accordance with the standard GB / T 17657-2022 "Test Methods for Physical and Chemical Properties of Engineered Wood Panels and Decorative Engineered Wood Panels".

[0106] The antibacterial performance grades of the artificial boards prepared in the blank control group and the artificial boards prepared using PA-based composite masterbatches prepared in Examples 4-6 and Comparative Examples 1-3 were determined in accordance with the standard LY / T 1926-2020 "Test and Grading of Antibacterial Properties of Wood-based Panels and Wood (Bamboo) Products".

[0107] The anti-mildew properties of the artificial boards prepared in the blank control group and the artificial boards prepared using PA-based composite masterbatches prepared in Examples 4-6 and Comparative Examples 1-3 were determined in accordance with the standard LY / T 2230-2013 "Evaluation of Anti-mildew Performance of Wood-based Panels".

[0108] The corrosion resistance of the artificial boards prepared in the blank control group and the artificial boards prepared using PA-based composite masterbatches prepared in Examples 4-6 and Comparative Examples 1-3 were determined according to the standard LY / T 3044-2018 "Evaluation of Corrosion Resistance of Artificial Boards". The specific data are shown in Table 1.

[0109] Table 1 - Performance Test Data for Each Sample

[0110]

[0111] Data Analysis:

[0112] A comparative analysis of the data in Table 1 reveals that the mass abrasion loss of the material prepared using the PA-based composite masterbatch obtained by this invention is 1.1 g·1000 r. -1 The sample exhibits a scratch resistance rating of 4, an antibacterial rate of 96.4%, and a mildew resistance rating of 1, while also showing a mass loss rate of only 0.8% after corrosion. All these data are superior to the comparative example and the blank control group, indicating that:

[0113] In Comparative Example 1, the triazine powder used did not undergo an amidation construction step during the preparation process, and its structural state differed significantly from that of the corresponding powder in the examples. This difference altered the way the powder participated in the material structure construction during the composite masterbatch preparation stage, thereby affecting its dispersion state in the matrix and its synergistic relationship with other functional units. During material operation, when external loads and environmental factors act together, the synergistic response path originally formed based on a specific structural state is difficult to establish completely, and the interaction between functional units tends to be dispersed and staged, resulting in a weakening of the consistency of the composite system during the overall operation process, thus reflecting a decrease in the overall response level under multi-performance superposition test conditions.

[0114] In Comparative Example 2, a type of functional unit involved in structural construction during the melt blending stage was reduced during the preparation of the composite masterbatch, causing an adjustment in the structural configuration of the material system in the initial molding stage. Due to this change, when the material is exposed to external media and environmental disturbances during subsequent use, the original synergistic operation relationship between different functional units is partially weakened, and the response path formed during operation tends to be simplified. When the material is under long-term operation or multiple factors superimposed, some functional units are difficult to obtain synergistic support from other units in the system, which reduces the overall coordination of the operating state and thus shows different response characteristics in the composite performance test compared to the example.

[0115] In Comparative Example 3, no composite-modified functional powder was introduced during the composite masterbatch preparation stage. This resulted in the material system lacking a key synergistic link for coordinating environmental effects during the structural configuration stage. This structural difference caused the material's response to external environmental factors to change during operation. When damp heat, medium immersion, or environmental fluctuations coexist with the operating load, the internal structural state of the material is more prone to adjustment, which in turn affects the stable operation of other functional units. Since the original multi-unit collaborative sharing mechanism was not effectively established, the material showed a trend of reduced coordination during overall operation, thus reflecting a decrease in response capability in composite performance-related tests.

[0116] In the blank control group, the material system did not introduce multifunctional structural units for collaborative construction, resulting in a lack of composite structure configuration in the initial molding stage. During actual operation, when the material is subjected to the combined effects of external loads, environmental media, and changes in usage conditions, its internal response mainly depends on the physical properties of the matrix itself, and the operating path is relatively simple, making it difficult to form a multi-factor collaborative response mechanism. Under the superposition of multiple conditions, the internal stress transmission, structural stability, and interface state adjustment processes of the material lack effective coordination, making the overall operating state more sensitive to external disturbances. As a result, it exhibits different response characteristics from the composite system in composite performance related tests.

[0117] Ultimately, this demonstrates that the response characteristics exhibited by the material system during use are directly related to the structural configuration and operational path established during the molding stage. When only a polyamide resin matrix is ​​used, the system operation mainly relies on a single material property, and the response path is relatively concentrated. When some structural construction steps or synergistic units in the composite masterbatch are adjusted, the coordination relationship between the functional units within the system changes accordingly. The multi-factor synergistic response path formed during operation is weakened or reconstructed to varying degrees. These changes cause differences in the coordination and consistency of the overall operating state of the material under the combined effects of external loads, environmental media, and usage conditions, resulting in different response trends in relevant performance tests. Thus, it can be seen that the changes in material properties do not stem from the simple superposition of component quantities, but are closely related to the synergistic operational relationship formed by each unit in the composite system during the structural construction stage.

[0118] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing an antibacterial and aging-resistant PA-based composite masterbatch, characterized in that, Includes the following steps: Step 1: Using carboxylated triazine covalent framework powder as raw material, the carboxyl group is activated and reacted with an amino-containing compound to introduce a polyamide reactive structure on its surface, thus obtaining amidated triazine powder; Step 2: Hydrolysis and condensation are performed using a silicon source as a precursor to form a silicon-oxygen network structure, and a zinc component is introduced to form a zinc-silicon hybrid system. On this basis, a silver component is loaded and its immobilization is achieved to obtain zinc-silicon-silver antibacterial powder. Step 3: Using hexachlorocyclotriphosphazene as raw material, an aminosilane structure is introduced through substitution, and it undergoes an ion hybridization reaction with phosphotungstic acid to form phosphazene-phosphotungstic acid composite powder. Step 4: Weigh out the following by weight: 60 parts polyamide resin, 8-10 parts amidated triazine powder, 2-3 parts zinc-silicon-silver antibacterial powder, 6-8 parts phosphazene-phosphotungstic acid composite powder, and 2 parts processing aid. Add these to a twin-screw extruder, melt extrude, and granulate to obtain PA-based composite masterbatch.

2. The method for preparing an antibacterial and aging-resistant PA-based composite masterbatch according to claim 1, characterized in that, In step one, the preparation method of the amidated triazine powder is as follows: carboxylated triazine covalent framework powder and anhydrous tetrahydrofuran are added to a reaction vessel and stirred. After uniform dispersion, thionyl chloride and N,N-dimethylformamide are added. Under nitrogen protection, the reaction vessel is heated to 65-75℃ and stirred for 3-5 hours. After the reaction is completed, the reaction vessel is cooled to 0-5℃, 6-aminohexanoic acid and triethylamine are added, and then the temperature is raised to 55-65℃ and stirred for 3-5 hours. The amidated triazine powder is obtained after post-treatment.

3. The method for preparing an antibacterial and aging-resistant PA-based composite masterbatch according to claim 3, characterized in that, In the preparation of amidated triazine powder, the ratio of the carboxylated triazine covalent framework powder, anhydrous tetrahydrofuran, thionyl chloride, N,N-dimethylformamide, 6-aminohexanoic acid and triethylamine is 6-8g:100mL:12-16mL:0.8mL:5-7g:10mL.

4. The method for preparing an antibacterial and aging-resistant PA-based composite masterbatch according to claim 1, characterized in that, The carboxylated triazine covalent framework powder was prepared by the following method: Step I: Add 2,6-pyridinedicarboxynitrile, terephthalonitrile and zinc chloride to the reaction vessel and mix evenly. Seal the reaction vessel and heat it to 380-420℃. Keep the temperature for 18-22h and then process it to obtain triazine covalent framework matrix powder. Step II: Add the triazine covalent framework matrix powder, 65wt% nitric acid aqueous solution and deionized water to the reaction vessel and stir. After the mixture is uniform, heat the reaction vessel to 75-85℃ and keep it at that temperature for 5-7 hours. Post-processing yields carboxylated triazine covalent framework powder.

5. The method for preparing an antibacterial and aging-resistant PA-based composite masterbatch according to claim 4, characterized in that, In step I, the ratio of 2,6-pyridinedicarboxynitrile, terephthalonitrile, and zinc chloride is 10-12g:10g:150g; in step II, the ratio of triazine covalent framework matrix powder, 65wt% nitric acid aqueous solution, and deionized water is 8-10g:60-80mL:40mL.

6. The method for preparing an antibacterial and aging-resistant PA-based composite masterbatch according to claim 1, characterized in that, In step two, the preparation method of the zinc-silicon-silver antibacterial powder is as follows: tetraethyl orthosilicate, 3-aminopropyltriethoxysilane, deionized water and anhydrous ethanol are added to a reaction vessel and stirred. After mixing evenly, glacial acetic acid is added and the reaction vessel is heated to 30-35℃. After stirring at this temperature for 1.5-2.5h, zinc acetate dihydrate is added and stirred for 40-60min. Then, silver nitrate is added and stirred in the dark for 20-40min. After cooling the reaction vessel to 0-5℃, a reducing agent is added and stirred at this temperature for 30-60min. The zinc-silicon-silver antibacterial powder is obtained after post-processing.

7. The method for preparing an antibacterial and aging-resistant PA-based composite masterbatch according to claim 6, characterized in that, In the preparation of zinc-silicon-silver antibacterial powder, the ratio of tetraethyl orthosilicate, 3-aminopropyltriethoxysilane, deionized water, anhydrous ethanol, glacial acetic acid, zinc acetate dihydrate, silver nitrate, and reducing agent is 20-24 mL:10 mL:10 mL:100 mL:1 mL:3-5 g:0.8-1.0 g:20-30 mL, wherein the reducing agent is a 1-2 wt% sodium borohydride aqueous solution.

8. The method for preparing an antibacterial and aging-resistant PA-based composite masterbatch according to claim 1, characterized in that, In step three, the preparation method of the phosphazene-phosphotungstic acid composite powder is as follows: hexachlorocyclotriphosphazene and anhydrous acetonitrile are added to a reaction vessel and stirred. After complete dissolution, 3-aminopropyltriethoxysilane and triethylamine are added. The reaction vessel is heated to 55-65℃ and stirred for 7-9 hours. After stirring, the reaction vessel is cooled to 20-30℃, a modifier is added, and the mixture is stirred for 1.5-2.5 hours. The phosphazene-phosphotungstic acid composite powder is obtained after post-treatment.

9. The method for preparing an antibacterial and aging-resistant PA-based composite masterbatch according to claim 8, characterized in that, In the preparation of phosphazene-phosphotungstic acid composite powder, the ratio of hexachlorocyclotriphosphazene, anhydrous acetonitrile, 3-aminopropyltriethoxysilane, triethylamine and the modifier is 6-8g:100mL:18-20mL:18-21mL:20-30mL, wherein the modifier is obtained by mixing phosphotungstic acid and anhydrous ethanol in a ratio of 3-5g:20-30mL.

10. An antibacterial and aging-resistant PA-based composite masterbatch, characterized in that, The antibacterial and aging-resistant PA-based composite masterbatch is prepared using the preparation method of the antibacterial and aging-resistant PA-based composite masterbatch as described in any one of claims 1-9.

Images