Preparation method of pet mat capable of releasing negative ions

Abstract

The invention discloses a preparation method of a pet mat capable of releasing negative ions, belongs to the technical field of pet mat preparation, and aims to solve the technical problem that the antibacterial property and wear resistance of a negative ion type pet mat in the prior art need to be further improved. The invention relates to a preparation method of a pet mat capable of releasing negative ions. The preparation method comprises the following steps: preparing the pet mat by using antibacterial fiber spinning; modified diamine is used as an inlaid chain segment to react with terephthaloyl chloride to obtain long-chain polyamide, carboxyl terminated at the tail end of the long-chain polyamide reacts with sulfydryl on modified tourmaline with titanium dioxide particles loaded on the surface for chain extension, and chain extension polyamide is obtained; finally, a fluorine group and a silane coupling agent structure are introduced on the surface through reaction of secondary amino groups on the surface and aldehyde ketone, composite polyamide is obtained, the composite polyamide is further mixed with auxiliary materials, melt spinning is conducted, antibacterial fibers are obtained, and the high-performance pet mat is finally prepared after antibacterial fiber spinning is conducted.

Description

Technical Field

[0001] The invention relates to the technical field of pet mat preparation, and in particular to a method for preparing a pet mat capable of releasing negative ions. Background Art

[0002] Prior art CN118835342B discloses a negative ion antibacterial polyester fiber fabric and a preparation method thereof. The preparation method comprises the following steps: adding a hyperdispersant Solsperse 32500, a dispersant DISPERS 655, and a negative ion powder to ethylene glycol, and stirring uniformly to obtain a negative ion slurry; uniformly mixing terephthalic acid, ethylene glycol, and a catalyst, adding the mixture to an esterification and polycondensation reactor, and esterifying for 30-60 minutes; then uniformly adding the negative ion slurry and N,N-dihydroxyethyl-3-aminopropionic acid methyl ester over 60 minutes; removing excess ethylene glycol, increasing the temperature, reacting under low vacuum conditions, cooling and granulating to obtain polyester chips; drying the polyester chips and then spinning them, and weaving the obtained fibers to obtain a negative ion textile fabric. The polyester fiber fabric obtained by this invention has a high negative ion release amount and good spinning performance.

[0003] However, the above invention prepares a negative ion textile product by adding negative ion slurry into the esterification and polycondensation reaction system, granulating and spinning, but the release of negative ions depends on the physical dispersion of opal and tourmaline, lacks chemical bonding, and easily leads to uneven distribution of negative ion powder in the fiber matrix, reducing the release efficiency and durability, and limiting the negative ion generation efficiency. Secondly, the antibacterial effect mainly depends on negative ions, lacks multi-mechanism synergy, and is difficult to effectively inhibit bacteria and mites. The antibacterial functional groups introduced by the amino additives have weak binding force with the polyester main chain, and may degrade after long-term use, affecting the antibacterial stability. The overall design lacks interface optimization of negative ions and antibacterial components, and the synergy between functional components is insufficient, making it difficult to achieve long-lasting and efficient antibacterial and negative ion release performance.

[0004] In view of the technical defects in this aspect, a solution is now proposed. Summary of the Invention

[0005] The object of the present invention is to provide a method for preparing a pet mat that releases negative ions, so as to solve the technical problem in the prior art that the antibacterial performance and wear resistance of negative ion pet mats need to be further improved.

[0006] The purpose of the present invention can be achieved through the following technical solutions: A method for preparing a pet mat that releases negative ions comprises the following steps: S1, extruding the molten polyamide through a spinneret and transferring it to a side-blowing chamber, and then solidifying it through air cooling to obtain an antibacterial fiber; S2. Using antibacterial fiber to weave and prepare a pet mat; The molten polyamide comprises the following raw materials in parts by weight: 80-100 parts of composite polyamide, 5-8 parts of heat stabilizer, 2-4 parts of lubricant, 5-8 parts of antioxidant and 10-12 parts of filler; The preparation method of the composite polyamide comprises the following steps: after mixing and stirring a chain-extended polyamide, triethoxysilylbutyraldehyde, 4,4,4-trifluoro-2-butanone, γ-alumina and dimethyl sulfoxide, raising the temperature of the reactant system to 60-80°C, keeping the temperature for reaction for 2-3 hours, and performing post-treatment to obtain the modified polyamide; and under the protection of nitrogen, after mixing and stirring the modified polyamide and dimethyl sulfoxide, raising the temperature of the reactant system to 50-60°C, keeping the temperature for reaction for 20-25 minutes, adding triethylamine to the reactant system, continuing the keeping temperature for reaction for 5-8 minutes, dripping an ethyl bromide solution into the reactant system, continuously dripping for 1-2 hours, keeping the temperature for reaction for 3-4 hours, and performing post-treatment to obtain the composite polyamide.

[0007] The reaction equation for preparing composite polyurethane is: Where: ; .

[0008] The reaction principle for preparing composite polyurethane is as follows: under acidic conditions, the carbonyl oxygen of triethoxysilylbutyraldehyde is preferentially protonated to form an oxonium ion (the oxygen atom is connected to three substituents, including two carbon groups and one hydrogen atom, and carries a positive charge), which significantly enhances the electrophilicity of the carbonyl carbon. The lone pair of electrons of the nitrogen atom of the secondary amine attacks the carbonyl carbon of the triethoxysilylbutyraldehyde to form a tetrahedral intermediate, and then a molecule of water is removed to form an iminium ion. In an acidic environment, the carbonyl oxygen of 4,4,4-trifluoro-2-butanone is protonated to form an oxonium ion, which in turn activates α-hydrogen. The α-hydrogen of the protonated 4,4,4-trifluoro-2-butanone is abstracted by the adjacent carboxyl proton to form an enol structure. The double bond carbon carries a negative charge and becomes a strong nucleophilic site. The α-carbon of the enol form acts as a nucleophile to attack the electrophilic carbon of the iminium cation to form a new carbon-carbon bond. The intermediate stabilizes the charge through proton transfer and eventually removes the proton to generate a β-amino ketone product, thereby obtaining a modified polyamide. The nitrogen atom of the tertiary amine group on the modified polyamide has a lone pair of electrons. As a nucleophile, it attacks the α-carbon atom of bromoethane under the catalysis of triethylamine, resulting in an SN2 nucleophilic substitution reaction. The bromine atom falls off as a leaving group to generate a quaternary ammonium salt. Triethylamine maintains the alkalinity of the reaction system by accepting the generated hydrobromic acid, preventing the amine group from protonating or side reactions, and promoting the reaction to proceed in the forward direction, thereby finally preparing a composite polyamide.

[0009] Furthermore, in the preparation process of the modified polyamide, the amount ratio of the chain-extended polyamide, triethoxysilylbutyraldehyde, 4,4,4-trifluoro-2-butanone, γ-alumina and dimethyl sulfoxide is 20-24 g: 2.1-2.5 g: 1.0-1.5 g: 1-2 g: 80-100 mL, and the post-treatment includes: after the reaction is completed, the temperature of the reactant system is lowered to room temperature, the reactant system is transferred to a rotary evaporator with a salt bath temperature of 80-100° C., and reduced pressure distillation is performed until no liquid is extracted to obtain the modified polyamide; Furthermore, in the preparation process of the composite polyamide, the amount ratio of the modified polyamide, dimethyl sulfoxide, triethylamine and bromoethane solution is 5-8g:30-32mL:0.1-0.3g:10-12mL, wherein the bromoethane solution is obtained by mixing bromoethane and dimethyl sulfoxide in an amount ratio of 1-2g:10-12mL. The post-treatment includes: after the reaction is completed, the temperature of the reactant system is lowered to room temperature, the reactant system is transferred to a rotary evaporator with a salt bath temperature of 80-100°C, and reduced pressure distillation is performed until no liquid is extracted to obtain the composite polyamide.

[0010] Furthermore, the heat stabilizer is triphenyl phosphate; the lubricant is one or both of zinc stearate and polyethylene wax; the antioxidant is one or both of triphenyl phosphite and dilauryl sulfide; and the filler is one or both of white carbon black and calcium carbonate.

[0011] Furthermore, in step S1, the preparation method of the molten polyamide is as follows: after mixing and stirring the composite polyamide, the heat stabilizer, the lubricant, the antioxidant and the filler, the system temperature is increased to 240-260° C., and the mixture is stirred at the same temperature until the system is completely mixed, thereby obtaining the molten polyamide; Furthermore, in step S1, the spinneret has a circular hole shape, 36-40 holes, a hole diameter of 0.1-0.2 mm, and a spinning pressure of 80-100 bar. The atmosphere in the side-blowing chamber is air, with a relative humidity of 30-36%, a temperature of 20-25° C., and a flow rate of 5-8 m / s. Furthermore, in step S2, the textile process is as follows: the antibacterial fiber is spun into yarn by ring spinning, with a yarn count of 20-40 and a twist of 600-800 twists / m, a spinning environment temperature of 20-25°C, a relative humidity of 55-65%, a drafting multiple of 25-35 times, and a spindle speed of 8000-12000 rpm; the weaving adopts a plain weave method, with a warp density of 30-40 yarns / cm, a weft density of 20-30 yarns / cm, a weaving speed of 400-600 rpm, and a warp tension of 0.2-0.3 N / root. Finally, a rapier loom is used to make a single-layer structure with a thickness of 1-2 mm to obtain a pet pad.

[0012] Furthermore, the preparation method of the chain-extended polyamide comprises the following steps: A1. Modified diamine and deionized water were mixed and stirred, and the pH of the reaction system was adjusted to 8-10 using a saturated sodium hydroxide aqueous solution. Then, a terephthaloyl chloride solution was added to the reaction system, and the mixture was reacted at room temperature for 1-2 hours. After post-treatment, a long-chain polyamide was obtained. A2. Long-chain polyamide and N,N-dimethylformamide were mixed and stirred. The temperature of the reactant system was raised to 70-80° C. and stirred for 10-15 minutes. Trifluoromethanesulfonic acid was added to the reactant system, and modified tourmaline was added three times, each with an interval of 10-15 minutes. After the addition was completed, the mixture was kept warm for 40-60 minutes, and the chain-extended polyamide was obtained by post-treatment.

[0013] The reaction equation for preparing chain-extended polyamide is: Where: ;" ” indicates modified tourmaline.

[0014] The reaction principle for preparing the chain-extended polyamide is as follows: under alkaline conditions, the generated hydrogen chloride is neutralized to promote the amidation polycondensation reaction of the modified diamine and terephthaloyl chloride to proceed in the positive direction; during the post-treatment process, the terminal acyl chloride group is converted into a carboxyl group to obtain a modified polyamide with a long-chain structure; the terminal carboxyl group of the long-chain polyamide is catalyzed by trifluoromethanesulfonic acid to enhance its electrophilicity, promote the nucleophilic attack of the thiol group modified on the surface of the modified tourmaline, form a thioester bond, achieve chain extension, and finally prepare the chain-extended polyamide.

[0015] Furthermore, in step A1, the amount ratio of modified diamine, deionized water and terephthaloyl solution is 3-4g:20-30mL:20-25mL, wherein the terephthaloyl chloride solution is obtained by mixing terephthaloyl chloride and o-xylene in an amount ratio of 1-2g:20-25mL, and the post-treatment includes: after the reaction is completed, the temperature of the reactant system is lowered to room temperature, the reactant system is transferred to a rotary evaporator with a salt bath temperature of 80-100°C, and reduced pressure distillation is performed until no liquid is extracted to obtain a long-chain polyamide; Furthermore, in step A2, the usage ratio of long-chain polyamide, N,N-dimethylformamide, trifluoromethanesulfonic acid and modified tourmaline is 4-6g:20-30mL:0.2-0.3g:0.5-0.8g, and the post-treatment includes: after the reaction is completed, after the temperature of the high-pressure reactor is reduced to room temperature, the reaction liquid is transferred to a rotary evaporator with a salt bath temperature of 80-100°C, and distilled under reduced pressure until no liquid is extracted to obtain extended chain polyamide.

[0016] Furthermore, the preparation method of the modified diamine is as follows: under the protection of nitrogen, dimethyldichlorosilane, anhydrous ethanol and deionized water are mixed and stirred, and the pH of the reaction system is adjusted to 8-10 using a saturated sodium hydroxide aqueous solution. The temperature of the reaction system is raised to 40-50°C, and the reaction is kept warm for 40-60 minutes. Then, an ethanolamine solution is added to the reaction system, and the reaction is kept warm for 10-15 minutes. The modified diamine is obtained by post-processing.

[0017] The reaction equation for preparing modified diamine is: The reaction principle for preparing modified diamine is as follows: dimethyldichlorosilane is hydrolyzed in water to form dimethylsilanediol. Dimethylsilanediol is unstable and undergoes further condensation reaction. The hydroxyl groups dehydrate to form siloxane bonds, forming a linear oligomeric siloxane structure. The hydroxyl groups of ethanolamine may dehydrate and condense with the silanol groups of siloxane to prepare modified diamine.

[0018] Furthermore, the amount ratio of dimethyldichlorosilane, anhydrous ethanol, deionized water and ethanolamine is 6-8g:20-25mL:10-12mL:10-12mL, wherein the ethanolamine solution is obtained by mixing ethanolamine and anhydrous ethanol in an amount ratio of 1-2mL:10-12mL. The post-treatment includes: after the reaction is completed, the temperature of the reactant system is lowered to room temperature, the reactant system is transferred to a rotary evaporator with a salt bath temperature of 80-100°C, and reduced pressure distillation is performed until no liquid is recovered to obtain modified diamine.

[0019] Furthermore, the preparation method of modified tourmaline comprises the following steps: B1. After mixing titanium tetrachloride and deionized water, tourmaline is added to the reactant system, and the reactant system is transferred to a reflux device, which is heated to reflux and kept at reflux for 2-3 hours, and then post-processed to obtain loaded tourmaline; B2. The loaded tourmaline, deionized water and anhydrous ethanol are mixed and stirred, and the pH value of the reaction system is adjusted to 8-10 with a saturated sodium hydroxide aqueous solution. Then, mercaptopropyltrimethoxysilane is added to the reaction system. The temperature of the reaction system is raised to 30-40° C. and the reaction is kept warm for 1-2 hours. The modified tourmaline is obtained by post-processing.

[0020] The reaction principle for preparing the modified diamine is as follows: titanium tetrachloride is hydrolyzed in the presence of water, titanium-chloride bonds are attacked by water molecules, titanium hydrate or titanium dioxide precursor is generated, the tourmaline surface provides active sites, titanium dioxide particles are loaded by adsorption or chemical bonding, the deposition and crystallization of titanium dioxide hydrolysis products are promoted by reflux, titanium dioxide is attached to the tourmaline surface in the form of nanoparticles, forming loaded tourmaline, mercaptopropyltrimethoxysilane is hydrolyzed under alkaline conditions, siloxy groups are attacked by water molecules, silanol is generated, the hydrolysis products are cross-linked with the loaded tourmaline surface through a condensation reaction, and the modified tourmaline is finally prepared.

[0021] Furthermore, in step B1, the ratio of titanium tetrachloride, deionized water and tourmaline is 2-3g:80mL:10-12g, and the post-treatment includes: after the reaction is completed, the temperature of the reactant system is lowered to room temperature, the reactant system is filtered to collect the filter cake, and the filter cake is washed 3-5 times with anhydrous ethanol and deionized water. After that, the filter cake is transferred to a vacuum drying oven at a temperature of 80°C and vacuum dried to constant weight to obtain loaded tourmaline; Furthermore, in step B2, the amount ratio of loaded tourmaline, deionized water, anhydrous ethanol and mercaptopropyltrimethoxysilane is 6-8g:20-24mL:10-12mL:1-2g, and the post-treatment includes: after the reaction is completed, the temperature of the reactant system is lowered to room temperature, the reactant system is filtered to collect the filter cake, the filter cake is washed 3-5 times with anhydrous ethanol and deionized water, and the filter cake is transferred to a vacuum drying oven at a temperature of 80°C, and vacuum dried to constant weight to obtain modified tourmaline.

[0022] The present invention has the following beneficial effects: 1. The long-chain polyamide prepared by the present invention forms a highly regular molecular chain through the reaction of modified diamine and terephthaloyl chloride, which gives the fiber excellent molecular orientation and crystallinity, thereby improving its intrinsic toughness and tensile strength. The terminal carboxyl group reacts with the thiol group of the titanium dioxide particles loaded on the surface of the modified tourmaline to extend the chain, forming a stable chemical cross-linking network, further enhancing the intermolecular bonding force of the fiber, reducing the tendency of chain segment slippage, and effectively resisting the wear caused by mechanical friction; the tourmaline particles are used as hard fillers and are evenly dispersed in the fiber matrix, increasing the surface hardness and scratch resistance, and slowing down the wear; the surface is introduced with titanium dioxide particles. fluorine groups; significantly reduce the friction coefficient of the fiber surface, forming a lubricating effect, reducing friction resistance when in contact with the outside world, thereby extending the service life of the fiber; silane coupling agent optimizes the interface bonding between the fiber and tourmaline and titanium dioxide, preventing the particles from falling off during friction and ensuring the durability of the wear resistance. The fiber structure prepared by the melt spinning process is dense and the molecular chains are arranged in an orderly manner. The surface functional groups and hard particles work together to form a tough wear-resistant layer, so that the pet pad can maintain its structural integrity under frequent use and mechanical stress, showing excellent wear resistance and providing a long-lasting and comfortable environment for pets.

[0023] 2. The long-chain polyamide prepared by the present invention forms a thioester bond through the reaction of the terminal carboxyl group with the thiol group of the titanium dioxide particles loaded on the surface of the modified tourmaline, thereby achieving chain extension, significantly improving the mechanical strength and chemical stability of the fiber, and ensuring the long-term binding of the antibacterial component. Secondly, the titanium dioxide particles trigger a photocatalytic reaction under light to generate active oxygen free radicals. These free radicals destroy the cell membranes, proteins and DNA of bacteria and mites through oxidation, effectively killing microorganisms. Moreover, the crystal structure of the modified tourmaline interferes with the metabolic process of microorganisms through a weak electric field effect, reducing their survival rate. The fluorine groups introduced on the fiber surface are generated by the reaction of secondary amino groups with aldehydes and ketones, significantly reducing the surface energy, reducing the attachment of bacteria and mites, and preventing the accumulation of dirt and the breeding of microorganisms. The silane coupling agent optimizes the interfacial compatibility between the fiber and the antibacterial component, promotes the uniform dispersion of titanium dioxide and tourmaline particles, and constructs an efficient antibacterial network. The synergistic effect of this multifunctional component, combined with hydrophobicity and structural stability, enables the pet mat to exhibit excellent antibacterial and mite removal properties, providing a healthy and hygienic use environment for pets.

[0024] 3. The surface of the modified tourmaline prepared by the present invention is loaded with titanium dioxide particles, and its crystal structure has natural electric polarization characteristics. It can stimulate the ionization of air molecules through pyroelectric and piezoelectric effects and continuously release negative ions. Secondly, the long-chain polyamide is formed by the siloxane structure generated by the hydrolysis of dimethyldichlorosilane and the end-modified diamine of ethanolamine, which enhances the chemical stability and flexibility of the fiber. The terminal carboxyl group of the polyamide reacts with the thiol group on the surface of the tourmaline to extend the chain, and the tourmaline particles are evenly anchored in the fiber matrix to ensure the stability of the negative ion release. The fluorine group and silane coupling agent structure introduced by the reaction of the secondary amino group on the surface with aldehydes and ketones improve the hydrophobicity of the fiber and the interfacial compatibility with tourmaline, reduce moisture interference, and optimize the electric polarization efficiency of the tourmaline. Moreover, the melt spinning process makes the fiber structure dense, the tourmaline particles are evenly distributed, and the negative ion release points are increased. The negative ions on the fiber surface improve the surrounding air quality through diffusion, creating an environment beneficial to the health of pets, thereby achieving excellent negative ion release performance. DETAILED DESCRIPTION

[0025] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] The white carbon black used in the present invention was purchased from Shanghai Jizhi Biochemical Technology Co., Ltd., with the product number S23920-1kg; The zinc stearate used in the present invention was purchased from Shanghai Haohong Biopharmaceutical Technology Co., Ltd., with product number 1066274; The tourmaline powder used in the present invention was purchased from Shanghai Huzheng New Materials Co., Ltd. with the product number RT-P30000.

[0027] Example 1 This embodiment provides a method for preparing modified tourmaline for preparing pet mats that release negative ions, comprising the following steps: Step I: Preparation of loaded tourmaline Weigh: 20.0g titanium tetrachloride and 800.0mL deionized water are added to the reactor and stirred. After adding 100.0g tourmaline to the reactor, the reactant system is transferred to a reflux device, the reflux device is heated to reflux, and the reflux is continued for 2h. After the reaction is completed, after the temperature of the reflux device is lowered to room temperature, the reaction liquid is filtered to collect the filter cake, and the filter cake is washed 3 times with anhydrous ethanol and deionized water. The filter cake is transferred to a vacuum drying oven at a temperature of 80°C and vacuum dried to constant weight to obtain loaded tourmaline.

[0028] Step II: Preparation of modified tourmaline Weigh: 60.0g loaded tourmaline, 200.0mL deionized water and 100.0mL anhydrous ethanol were added to the reactor and stirred, and the pH of the reaction system was adjusted to 8 with saturated sodium hydroxide aqueous solution, and then 10.0g mercaptopropyltrimethoxysilane was added to the reactor. The temperature of the reactor was raised to 30°C and kept warm for 2h. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction liquid was filtered to collect the filter cake, and the filter cake was washed 3 times with anhydrous ethanol and deionized water. The filter cake was transferred to a vacuum drying oven at a temperature of 80°C and vacuum dried to constant weight to obtain modified tourmaline.

[0029] Example 2 This embodiment provides a method for preparing modified tourmaline for preparing pet mats that release negative ions, comprising the following steps: Step I: Preparation of loaded tourmaline Weigh: 30.0g titanium tetrachloride and 800.0mL deionized water are added to the reactor and stirred. After adding 120.0g tourmaline to the reactor, the reactant system is transferred to a reflux device, the reflux device is heated to reflux, and the reflux is continued for 3 hours. After the reaction is completed, after the temperature of the reflux device is lowered to room temperature, the reaction liquid is filtered to collect the filter cake, and the filter cake is washed 5 times with anhydrous ethanol and deionized water. The filter cake is transferred to a vacuum drying oven at a temperature of 80°C and vacuum dried to constant weight to obtain loaded tourmaline.

[0030] Step II: Preparation of modified tourmaline Weigh: 80.0g loaded tourmaline, 240.0mL deionized water and 120.0mL anhydrous ethanol are added to the reactor and stirred, and the pH of the reaction system is adjusted to 10 with a saturated sodium hydroxide aqueous solution, and then 20.0g of mercaptopropyltrimethoxysilane is added to the reactor. The temperature of the reactor is raised to 40°C and kept warm for 2h. After the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is filtered to collect the filter cake, and the filter cake is washed 5 times with anhydrous ethanol and deionized water. The filter cake is transferred to a vacuum drying oven at a temperature of 80°C and vacuum dried to constant weight to obtain modified tourmaline.

[0031] Example 3 This embodiment provides a method for preparing modified diamine for preparing pet bedding that releases negative ions, comprising the following steps: Step I: Preparation of loaded tourmaline Weigh: 25.0g titanium tetrachloride and 800.0mL deionized water are added to the reactor and stirred. After adding 100.0g tourmaline to the reactor, the reactant system is transferred to a reflux device, the reflux device is heated to reflux, and the reflux is continued for 3 hours. After the reaction is completed, after the temperature of the reflux device is lowered to room temperature, the reaction liquid is filtered to collect the filter cake, and the filter cake is washed 5 times with anhydrous ethanol and deionized water. The filter cake is transferred to a vacuum drying oven at a temperature of 80°C and vacuum dried to constant weight to obtain loaded tourmaline.

[0032] Step II: Preparation of modified tourmaline Weigh: 80.0g loaded tourmaline, 240.0mL deionized water and 120.0mL anhydrous ethanol are added to the reactor and stirred, and the pH of the reaction system is adjusted to 9 with a saturated sodium hydroxide aqueous solution, and then 16.0g mercaptopropyltrimethoxysilane is added to the reactor. The temperature of the reactor is raised to 35°C and kept warm for 2h. After the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is filtered to collect the filter cake, and the filter cake is washed 4 times with anhydrous ethanol and deionized water. The filter cake is transferred to a vacuum drying oven at a temperature of 80°C and vacuum dried to constant weight to obtain modified tourmaline.

[0033] Example 4 This embodiment provides a method for preparing modified tourmaline for preparing pet mats that release negative ions, comprising the following steps: Weigh: 10.0 mL of ethanolamine and 100.0 mL of anhydrous ethanol and mix to obtain an ethanolamine solution; Under the protection of nitrogen, 60.0 g of dimethyldichlorosilane, 200.0 mL of anhydrous ethanol and 100.0 mL of deionized water were weighed and added to a reactor with stirring. After adjusting the pH of the reactant system to 8 with a saturated sodium hydroxide aqueous solution, the temperature of the reactor was raised to 40°C and kept warm for 40 minutes. Then, 100.0 mL of ethanolamine solution was added to the reactor and kept warm for 10 minutes. After the reaction was completed, the temperature of the reactor was lowered to room temperature, and the reactor was transferred to a rotary evaporator with a salt bath temperature of 80°C. It was distilled under reduced pressure until no liquid was extracted to obtain modified diamine.

[0034] Example 5 This embodiment provides a method for preparing modified diamine for preparing pet bedding that releases negative ions, comprising the following steps: Weigh: 20.0 mL of ethanolamine and 120.0 mL of anhydrous ethanol and mix to obtain an ethanolamine solution; Under the protection of nitrogen, 80.0 g of dimethyldichlorosilane, 250.0 mL of anhydrous ethanol and 120.0 mL of deionized water were weighed and added to a reactor with stirring. After adjusting the pH of the reactant system to 10 with a saturated sodium hydroxide aqueous solution, the temperature of the reactor was raised to 50° C. and kept warm for 60 minutes. Then, 120.0 mL of ethanolamine solution was added to the reactor and kept warm for 15 minutes. After the reaction was completed, the temperature of the reactor was lowered to room temperature, and the reactor was transferred to a rotary evaporator with a salt bath temperature of 100° C. and distilled under reduced pressure until no liquid was extracted to obtain modified diamine.

[0035] Example 6 This embodiment provides a method for preparing modified diamine for preparing pet bedding that releases negative ions, comprising the following steps: Weigh: 16.0 mL of ethanolamine and 120.0 mL of anhydrous ethanol to mix to obtain an ethanolamine solution; Under the protection of nitrogen, 72.0 g of dimethyldichlorosilane, 240.0 mL of anhydrous ethanol and 120.0 mL of deionized water were weighed and added to a reactor with stirring. After adjusting the pH of the reactant system to 9 with a saturated sodium hydroxide aqueous solution, the temperature of the reactor was raised to 45°C and kept warm for 50 minutes. Then, 120.0 mL of ethanolamine solution was added to the reactor and kept warm for 15 minutes. After the reaction was completed, the temperature of the reactor was lowered to room temperature, and the reactor was transferred to a rotary evaporator with a salt bath temperature of 90°C. The mixture was distilled under reduced pressure until no liquid was extracted to obtain modified diamine.

[0036] Example 7 This embodiment provides a method for preparing a composite polyamide for preparing a pet mat that releases negative ions, comprising the following steps: Step 1: Preparation of long-chain polyamide Weigh: 10.0 g of terephthaloyl chloride and 200.0 mL of o-xylene and mix to obtain a terephthaloyl chloride solution; Weigh: 35.0 g of the modified diamine prepared in Example 4 and 200.0 mL of deionized water were added to the reactor and stirred. After adjusting the pH of the reaction system to 8 with a saturated sodium hydroxide aqueous solution, 200.0 mL of phthaloyl chloride solution was added to the reactor and reacted at room temperature for 1 hour. After the reaction was completed, the temperature of the reactor was lowered to room temperature, and the reaction liquid was transferred to a rotary evaporator with a salt bath temperature of 80°C, and distilled under reduced pressure until no liquid was extracted to obtain a long-chain polyamide.

[0037] Step ②, preparation of chain-extended polyamide Weigh: 40.0g long-chain polyamide and 200.0mL N,N-dimethylformamide are added to the reactor and stirred. The temperature of the reactor is raised to 70°C. After stirring for 10 minutes, 2.0g of trifluoromethanesulfonic acid is added to the reactor, and 5.0g of the modified tourmaline prepared in Example 1 is added three times, each time with an interval of 10 minutes. After the addition is completed, the reaction is kept warm for 40 minutes. After the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction solution is transferred to a rotary evaporator with a salt bath temperature of 80°C, and distilled under reduced pressure until no liquid is extracted to obtain a long-chain polyamide.

[0038] Step ③, preparation of modified polyamide Weigh: 20.0g of extended chain polyamide, 2.1g of triethoxysilylbutyraldehyde, 1.0g of 4,4,4-trifluoro-2-butanone, 1.0g of γ-alumina and 80.0mL of dimethyl sulfoxide, add them into the reactor and stir, raise the temperature of the reactor to 60°C, keep the reaction for 2h, after the reaction is completed, lower the temperature of the reactor to room temperature, transfer the reaction liquid to a rotary evaporator with a salt bath temperature of 80°C, and distill under reduced pressure until no liquid is extracted to obtain modified polyamide.

[0039] Step ④: Preparation of composite polyamide Weigh: 1.0 g of ethyl bromide and 10.0 mL of dimethyl sulfoxide to obtain an ethyl bromide solution; Under the protection of nitrogen, 5.0 g of modified polyamide and 30.0 mL of dimethyl sulfoxide were weighed and added to a reactor with stirring. The temperature of the reactor was raised to 50°C. After stirring for 20 minutes, 0.1 g of triethylamine was added to the reactor. After stirring for 5 minutes, 10.0 mL of bromoethane solution was added dropwise to the reactor. The addition was continued for 1 hour. The reactor was stirred for 3 hours. After the reaction was completed, the temperature of the reactor was lowered to room temperature. The reactor was transferred to a rotary evaporator with a salt bath temperature of 80°C and distilled under reduced pressure until no liquid was extracted to obtain a composite polyamide.

[0040] Example 8 This embodiment provides a method for preparing a composite polyamide for preparing a pet mat that releases negative ions, comprising the following steps: Step 1: Preparation of long-chain polyamide Weigh: 20.0 g of terephthaloyl chloride and 250.0 mL of o-xylene are mixed to obtain a terephthaloyl chloride solution; Weigh: 40.0 g of the modified diamine prepared in Example 5 and 300.0 mL of deionized water were added to the reactor and stirred. After adjusting the pH of the reaction system to 10 with a saturated sodium hydroxide aqueous solution, 250.0 mL of phthaloyl chloride solution was added to the reactor and reacted at room temperature for 2 h. After the reaction was completed, the temperature of the reactor was lowered to room temperature, and the reaction solution was transferred to a rotary evaporator with a salt bath temperature of 100 ° C. and distilled under reduced pressure until no liquid was extracted to obtain a long-chain polyamide.

[0041] Step ②, preparation of chain-extended polyamide Weigh: 54.0g long-chain polyamide and 300.0mL N,N-dimethylformamide are added to the reactor and stirred. The temperature of the reactor is raised to 80°C. After stirring for 15 minutes, 3.0g of trifluoromethanesulfonic acid is added to the reactor, and 8.0g of the modified tourmaline prepared in Example 2 is added three times, each time with an interval of 15 minutes. After the addition is completed, the reaction is kept warm for 60 minutes. After the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction solution is transferred to a rotary evaporator with a salt bath temperature of 100°C, and distilled under reduced pressure until no liquid is extracted to obtain a long-chain polyamide.

[0042] Step ③, preparation of modified polyamide Weigh: 24.0g of extended chain polyamide, 2.5g of triethoxysilylbutyraldehyde, 1.5g of 4,4,4-trifluoro-2-butanone, 2.0g of γ-alumina and 100.0mL of dimethyl sulfoxide are added to the reactor and stirred. The temperature of the reactor is raised to 80°C and kept warm for 3 hours. After the reaction is completed, the temperature of the reactor is lowered to room temperature, and the reaction liquid is transferred to a rotary evaporator with a salt bath temperature of 100°C, and distilled under reduced pressure until no liquid is extracted to obtain modified polyamide.

[0043] Step ④: Preparation of composite polyamide Weigh: 2.0 g of ethyl bromide and 12.0 mL of dimethyl sulfoxide to obtain an ethyl bromide solution; Under the protection of nitrogen, 8.0 g of modified polyamide and 32.0 mL of dimethyl sulfoxide were weighed and added to a reactor with stirring. The temperature of the reactor was raised to 60° C. and stirred for 25 minutes. Then, 0.3 g of triethylamine was added to the reactor. After stirring for 8 minutes, 12.0 mL of bromoethane solution was added dropwise to the reactor. The addition was continued for 2 hours and stirred for 4 hours. After the reaction was completed, the temperature of the reactor was lowered to room temperature, and the reactor was transferred to a rotary evaporator with a salt bath temperature of 100° C. and distilled under reduced pressure until no liquid was extracted to obtain a composite polyamide.

[0044] Example 9 This embodiment provides a method for preparing a composite polyamide for preparing a pet mat that releases negative ions, comprising the following steps: Step 1: Preparation of long-chain polyamide Weigh: 16.0 g of terephthaloyl chloride and 210.0 mL of o-xylene and mix to obtain a terephthaloyl chloride solution; Weigh: 36.0 g of the modified diamine prepared in Example 6 and 250.0 mL of deionized water were added to the reactor and stirred. After adjusting the pH of the reaction system to 9 with a saturated sodium hydroxide aqueous solution, 240.0 mL of phthaloyl chloride solution was added to the reactor and reacted at room temperature for 2 h. After the reaction was completed, the temperature of the reactor was lowered to room temperature, and the reaction liquid was transferred to a rotary evaporator with a salt bath temperature of 90 ° C. and distilled under reduced pressure until no liquid was extracted to obtain a long-chain polyamide.

[0045] Step ②, preparation of chain-extended polyamide Weigh: 45.0g long-chain polyamide and 250.0mL N,N-dimethylformamide are added to the reactor and stirred. The temperature of the reactor is raised to 75°C. After stirring for 12 minutes, 2.5g of trifluoromethanesulfonic acid is added to the reactor, and 7.2g of the modified tourmaline prepared in Example 3 is added three times, each time with an interval of 12 minutes. After the addition is completed, the reaction is kept warm for 50 minutes. After the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction solution is transferred to a rotary evaporator with a salt bath temperature of 90°C, and distilled under reduced pressure until no liquid is extracted to obtain a long-chain polyamide.

[0046] Step ③, preparation of modified polyamide Weigh: 21.0g of extended chain polyamide, 2.4g of triethoxysilylbutyraldehyde, 1.2g of 4,4,4-trifluoro-2-butanone, 1.6g of γ-alumina and 90.0mL of dimethyl sulfoxide, add them into the reactor and stir, raise the temperature of the reactor to 70°C, and keep the reaction for 3h. After the reaction is completed, the temperature of the reactor is lowered to room temperature, and the reaction liquid is transferred to a rotary evaporator with a salt bath temperature of 90°C, and distilled under reduced pressure until no liquid is extracted to obtain modified polyamide.

[0047] Step ④: Preparation of composite polyamide Weigh: 1.5 g of ethyl bromide and 10.0 mL of dimethyl sulfoxide to obtain an ethyl bromide solution; Under the protection of nitrogen, 7.2 g of modified polyamide and 32.0 mL of dimethyl sulfoxide were weighed and added to the reactor with stirring. The temperature of the reactor was raised to 54°C. After stirring for 24 minutes, 0.3 g of triethylamine was added to the reactor. After stirring for 6 minutes, 10.0 mL of bromoethane solution was added dropwise to the reactor. The addition was continued for 2 hours. The reactor was stirred for 4 hours. After the reaction was completed, the temperature of the reactor was lowered to room temperature. The reactor was transferred to a rotary evaporator with a salt bath temperature of 90°C and distilled under reduced pressure until no liquid was extracted to obtain a composite polyamide.

[0048] Example 10 This embodiment provides a method for preparing a pet mat that releases negative ions, comprising the following steps: Step 1: Preparation of antibacterial fiber Weigh 80.0 parts of the composite polyamide prepared in Example 7, 5.0 parts of triphenyl phosphate, 2.0 parts of zinc stearate, 5.0 parts of triphenyl phosphite, and 10.0 parts of white carbon black, add them to a stirring kettle and stir. Raise the temperature of the stirring kettle to 240° C. and keep stirring until the system is completely mixed to obtain a molten polyamide. The molten polyamide was passed through a spinneret with a circular channel, 36 holes, and a pore diameter of 0.1 mm, maintaining a spinning pressure of 80 bar. After extrusion, it was transferred to a side-blowing chamber. The atmosphere in the side-blowing chamber was air, the relative humidity was 30%, the temperature was 20°C, and the flow rate was maintained at 5 m / s. After air cooling and curing, the antibacterial fiber was obtained.

[0049] Step 2: Prepare pet mat The antibacterial fiber was spun into yarn by ring spinning, with a yarn count of 20 and a twist of 600 twists / m. The spinning environment temperature was 20°C, the relative humidity was 55%, the drafting ratio was 25 times, and the spindle speed was 8000 rpm. The weaving adopted a plain weave method with a warp density of 30 yarns / cm, a weft density of 20 yarns / cm, a weaving speed of 400 rpm, and a warp tension of 0.2 N / strand. Finally, a rapier loom was used to make a single-layer structure with a thickness of 1 mm to obtain a pet pad.

[0050] Example 11 This embodiment provides a method for preparing a pet mat that releases negative ions, comprising the following steps: Step 1: Preparation of antibacterial fiber Weigh 100.0 parts of the composite polyamide prepared in Example 8, 8.0 parts of triphenyl phosphate, 4.0 parts of zinc stearate, 8.0 parts of triphenyl phosphite, and 12.0 parts of white carbon black, add them to a stirring kettle and stir. Raise the temperature of the stirring kettle to 260.0° C. and keep stirring until the system is completely mixed to obtain a molten polyamide. The molten polyamide is passed through a spinneret with a circular channel, 40 holes, and a pore diameter of 0.2 mm, maintaining a spinning pressure of 100 bar. After extrusion, it is transferred to a side-blowing chamber. The atmosphere in the side-blowing chamber is air, the relative humidity is 36%, the temperature is 25°C, and the flow rate is maintained at 8 m / s. After air cooling and curing, the antibacterial fiber is obtained.

[0051] Step 2: Prepare pet mat The antibacterial fiber was spun into yarn by ring spinning, with a yarn count of 40 and a twist of 800 twists / m. The spinning environment temperature was 25°C, the relative humidity was 65%, the draft was 35 times, and the spindle speed was 12000pm. The weaving adopted a plain weave method with a warp density of 40 yarns / cm, a weft density of 30 yarns / cm, a weaving speed of 600rpm, and a warp tension of 0.3N / strand. Finally, a rapier loom was used to make a single-layer structure with a thickness of 2 mm to obtain a pet pad.

[0052] Example 12 This embodiment provides a method for preparing a pet mat that releases negative ions, comprising the following steps: Step 1: Preparation of antibacterial fiber Weigh 96.0 parts of the composite polyamide prepared in Example 9, 7.2 parts of triphenyl phosphate, 3.6 parts of zinc stearate, 6.4 parts of triphenyl phosphite, and 10.0 parts of white carbon black, add them to a stirring kettle and stir. Raise the temperature of the stirring kettle to 260° C. and keep stirring until the system is completely mixed to obtain a molten polyamide. The molten polyamide was passed through a spinneret with a circular channel, 36 holes, and a pore diameter of 0.2 mm, maintaining a spinning pressure of 90 bar. After extrusion, it was transferred to a side-blowing chamber. The atmosphere in the side-blowing chamber was air, the relative humidity was 32%, the temperature was 24°C, and the flow rate was maintained at 6 m / s. After air cooling and curing, the antibacterial fiber was obtained.

[0053] Step 2: Prepare pet mat The antibacterial fiber was spun into yarn by ring spinning, with a yarn count of 36 and a twist of 700 twists / m. The spinning environment temperature was 24°C, the relative humidity was 60%, the drafting ratio was 30 times, and the spindle speed was 10,000 rpm. The weaving adopted a plain weave method with a warp density of 36 yarns / cm, a weft density of 24 yarns / cm, a weaving speed of 500 rpm, and a warp tension of 0.3 N / strand. Finally, a rapier loom was used to make a single-layer structure with a thickness of 1.6 mm to obtain a pet pad.

[0054] Comparative Example 1 The difference between this comparative example and Example 12 is that in the preparation process ① of the composite polyurethane used, the use of modified diamine is eliminated and an equal amount of ethylenediamine is used instead.

[0055] Comparative Example 2 The difference between this comparative example and Example 12 is that in the preparation process ② of the composite polyurethane used, step I is omitted during the preparation of the modified tourmaline used.

[0056] Comparative Example 3 The difference between this comparative example and Example 12 is that in the preparation process ② of the composite polyurethane used, step II is omitted during the preparation of the modified tourmaline used.

[0057] Performance testing: The negative ion concentrations of the pet mats prepared in Examples 10-12 and Comparative Examples 1-3 were tested with reference to the standard GB / T 30128-2013 "Testing and Evaluation of Negative Ion Generation in Textiles"; With reference to the standard GB / T 20944.3-2008 "Evaluation of Antibacterial Properties of Textiles Part 3: Oscillation Method", the antibacterial rates of the pet mats prepared in Examples 10-12 and Comparative Examples 1-3 were tested, wherein the selected bacterial species were Staphylococcus aureus and Escherichia coli, respectively; The mite removal performance of the pet mats prepared in Examples 10-12 and Comparative Examples 1-3 was evaluated with reference to the standard GB / T 24253-2009 "Evaluation of Anti-mite Performance of Textiles"; The volume wear of the pet mats prepared in Examples 10-12 and Comparative Examples 1-3 was tested in accordance with the standard GB / T 9867-2008 "Determination of wear resistance of vulcanized or thermoplastic rubber (rotating roller abrader method)". Specific data are shown in Table 1.

[0058] Table 1 - Performance test data of each sample

[0059] Data Analysis: Comparing and analyzing the data in Table 1, it can be found that the negative ion concentration of the pet mat prepared by the present invention is 8396 / cm -3 The disinfecting rate of Staphylococcus is 99.1%, the disinfecting rate of Escherichia coli is 99.5%, and the mite removal performance is extremely strong while the volume wear is 9.9mm 3 , all data are better than those of the comparative example; The long-chain polyamide reacts with the thiol groups of the titanium dioxide particles loaded on the surface of the modified tourmaline through the terminal carboxyl groups to form thioester bonds, achieving chain extension, significantly improving the mechanical strength and chemical stability of the fiber and ensuring the long-term binding of the antibacterial component. Secondly, the titanium dioxide particles trigger a photocatalytic reaction under light, generating reactive oxygen free radicals. These free radicals destroy the cell membranes, proteins and DNA of bacteria and mites through oxidation, effectively killing microorganisms. Furthermore, the crystal structure of the modified tourmaline interferes with the metabolic process of microorganisms through a weak electric field effect, reducing their survival rate. The fluorine groups introduced on the fiber surface react with aldehydes and ketones through secondary amino groups, significantly reducing surface energy, reducing the attachment of bacteria and mites, and preventing the accumulation of dirt and the breeding of microorganisms. The silane coupling agent optimizes the interfacial compatibility between the fiber and the antibacterial component, promotes the uniform dispersion of titanium dioxide and tourmaline particles, and constructs an efficient antibacterial network. The synergistic effect of these multifunctional components, combined with hydrophobicity and structural stability, makes the pet mat exhibit excellent antibacterial and mite removal properties, providing a healthy and hygienic use environment for pets. The modified tourmaline prepared by the present invention is loaded with titanium dioxide particles on its surface. Its crystal structure has natural electrical polarization characteristics and can stimulate the ionization of air molecules through pyroelectric and piezoelectric effects to continuously release negative ions. Secondly, the long-chain polyamide is formed by the siloxane structure generated by the hydrolysis of dimethyldichlorosilane and the end-modified diamine of ethanolamine, thereby enhancing the chemical stability and flexibility of the fiber. The terminal carboxyl groups of the polyamide react with the thiol groups on the surface of the tourmaline to extend the chain, uniformly anchoring the tourmaline particles to the fiber matrix and ensuring the stability of negative ion release. The fluorine groups and silane coupling agent structure introduced by the reaction of the secondary amino groups on the surface with aldehydes and ketones improve the hydrophobicity of the fiber and the interfacial compatibility with the tourmaline, reduce moisture interference, and optimize the electrical polarization efficiency of the tourmaline. Furthermore, the melt spinning process makes the fiber structure dense and the tourmaline particles evenly distributed, increasing the negative ion release points. The negative ions on the fiber surface improve the surrounding air quality through diffusion, creating an environment beneficial to the health of pets, thereby achieving excellent negative ion release performance. The results show that long-chain polyamide forms highly regular molecular chains through the reaction of modified diamine and terephthaloyl chloride, which gives the fiber excellent molecular orientation and crystallinity, thereby improving its intrinsic toughness and tensile strength. The terminal carboxyl group reacts with the thiol group of titanium dioxide particles loaded on the surface of modified tourmaline to extend the chain, forming a stable chemical cross-linking network, further enhancing the intermolecular bonding force of the fiber, reducing the tendency of chain segment slippage, and effectively resisting the wear caused by mechanical friction; the tourmaline particles are evenly dispersed in the fiber matrix as hard fillers, increasing the surface hardness and scratch resistance, and slowing down the wear; the fluorine-based The fiber surface friction coefficient is significantly reduced, forming a lubricating effect, reducing frictional resistance when in contact with the outside world, thereby extending the service life of the fiber; the silane coupling agent optimizes the interface bonding between the fiber and tourmaline and titanium dioxide, preventing the particles from falling off during friction and ensuring the durability of the wear resistance. The fiber structure prepared by the melt spinning process is dense and the molecular chains are arranged in an orderly manner. The surface functional groups and hard particles work together to form a tough wear-resistant layer, allowing the pet pad to maintain its structural integrity under frequent use and mechanical stress, showing excellent wear resistance and providing a long-lasting and comfortable environment for pets. Finally, the present invention explains that after hydrolyzing dimethyldichlorosilane to produce a long-chain siloxane structure, ethanolamine is used for end-capping to obtain a modified diamine, and the modified diamine is used as an embedded segment to react with terephthaloyl chloride to obtain a long-chain polyamide. The carboxyl group at the end of the long-chain polyamide reacts with the thiol group on the modified tourmaline with titanium dioxide particles loaded on the surface to extend the chain to obtain an extended chain polyamide. Finally, the secondary amino group on the surface reacts with aldehydes and ketones to introduce fluorine groups and silane coupling agent structures on the surface to obtain a composite polyamide. The composite polyamide is further mixed with auxiliary materials and melt-spun to obtain an antibacterial fiber. After the antibacterial fiber is spun, a high-performance pet pad is finally prepared.

[0060] The above content is merely an example and explanation of the structure of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described, or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they shall fall within the scope of protection of the present invention.

[0061] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0062] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a pet mat that releases negative ions, characterized in that: The following steps are involved: S1, extruding the molten polyamide through a spinneret and transferring it to a side-blowing chamber, and then solidifying it through air cooling to obtain an antibacterial fiber; S2. Using antibacterial fiber to weave and prepare a pet mat; The molten polyamide comprises the following raw materials in parts by weight: 80-100 parts of composite polyamide, 5-8 parts of heat stabilizer, 2-4 parts of lubricant, 5-8 parts of antioxidant and 10-12 parts of filler; The preparation method of the composite polyamide comprises the following steps: after mixing and stirring a chain-extended polyamide, triethoxysilylbutyraldehyde, 4,4,4-trifluoro-2-butanone, γ-alumina and dimethyl sulfoxide, raising the temperature of the reactant system to 60-80°C, keeping the temperature for reaction for 2-3 hours, and performing post-treatment to obtain the modified polyamide; and under the protection of nitrogen, after mixing and stirring the modified polyamide and dimethyl sulfoxide, raising the temperature of the reactant system to 50-60°C, keeping the temperature for reaction for 20-25 minutes, adding triethylamine to the reactant system, continuing the keeping temperature for reaction for 5-8 minutes, dripping an ethyl bromide solution into the reactant system, continuously dripping for 1-2 hours, keeping the temperature for reaction for 3-4 hours, and performing post-treatment to obtain the composite polyamide.

2. The method for preparing a pet mat that releases negative ions according to claim 1, characterized in that: In step S1, the spinneret has a circular channel, 36-40 holes, a pore diameter of 0.1-0.2 mm, and a spinning pressure of 80-100 bar. The atmosphere in the side-blowing chamber is air, with a relative humidity of 30-36%, a temperature of 20-25° C., and a flow rate of 5-8 m / s.

3. The method for preparing a pet mat that releases negative ions according to claim 1, characterized in that: In the preparation process of the modified polyamide, the amount ratio of the chain extended polyamide, triethoxysilyl butyraldehyde, 4,4,4-trifluoro-2-butanone, γ-alumina and dimethyl sulfoxide is 20-24g:2.1-2.5g:1.0-1.5g:1-2g:80-100mL; in the preparation process of the composite polyamide, the amount ratio of the modified polyamide, dimethyl sulfoxide, triethylamine and bromoethane solution is 5-8g:30-32mL:0.1-0.3g:10-12mL, wherein the bromoethane solution is obtained by mixing bromoethane and dimethyl sulfoxide at a ratio of 1-2g:10-12mL.

4. The method for preparing a pet mat that releases negative ions according to claim 1, wherein: The preparation method of the chain-extended polyamide comprises the following steps: A1. Modified diamine and deionized water were mixed and stirred, and the pH of the reaction system was adjusted to 8-10 using a saturated sodium hydroxide aqueous solution. Then, a terephthaloyl chloride solution was added to the reaction system, and the mixture was reacted at room temperature for 1-2 hours. After post-treatment, a long-chain polyamide was obtained. A2. Long-chain polyamide and N,N-dimethylformamide were mixed and stirred. The temperature of the reactant system was raised to 70-80° C. and stirred for 10-15 minutes. Trifluoromethanesulfonic acid was added to the reactant system, and modified tourmaline was added three times, each with an interval of 10-15 minutes. After the addition was completed, the mixture was kept warm for 40-60 minutes, and the chain-extended polyamide was obtained by post-treatment.

5. The method for preparing a pet mat that releases negative ions according to claim 4, characterized in that: In step A1, the amount ratio of the modified diamine, deionized water and terephthaloyl solution is 3-4g:20-30mL:20-25mL, wherein the terephthaloyl chloride solution is obtained by mixing terephthaloyl chloride and o-xylene in an amount ratio of 1-2g:20-25mL; in step A2, the amount ratio of the long-chain polyamide, N,N-dimethylformamide, trifluoromethanesulfonic acid and modified tourmaline is 4-6g:20-30mL:0.2-0.3g:0.5-0.8g.

6. The method for preparing a pet mat that releases negative ions according to claim 4, characterized in that: The preparation method of the modified diamine comprises the following steps: under the protection of nitrogen, dimethyldichlorosilane, anhydrous ethanol and deionized water are mixed and stirred, a saturated sodium hydroxide aqueous solution is used to adjust the pH value of the reaction system to 8-10, the temperature of the reaction system is increased to 40-50° C., the reaction is carried out by heat preservation for 40-60 minutes, an ethanolamine solution is added to the reaction system, the reaction is carried out by heat preservation for 10-15 minutes, and post-treatment is performed to obtain the modified diamine.

7. The method for preparing a pet mat that releases negative ions according to claim 6, characterized in that: The dosage ratio of dimethyldichlorosilane, anhydrous ethanol, deionized water and ethanolamine is 6-8g:20-25mL:10-12mL:10-12mL, wherein the ethanolamine solution is obtained by mixing ethanolamine and anhydrous ethanol in a dosage ratio of 1-2mL:10-12mL.

8. The method for preparing a pet mat that releases negative ions according to claim 4, characterized in that: The preparation method of the modified tourmaline comprises the following steps: B1. After mixing titanium tetrachloride and deionized water, tourmaline is added to the reactant system, and the reactant system is transferred to a reflux device, which is heated to reflux and kept at reflux for 2-3 hours, and then post-processed to obtain loaded tourmaline; B2. The loaded tourmaline, deionized water and anhydrous ethanol are mixed and stirred, and the pH value of the reaction system is adjusted to 8-10 with a saturated sodium hydroxide aqueous solution. Then, mercaptopropyltrimethoxysilane is added to the reaction system. The temperature of the reaction system is raised to 30-40° C. and the reaction is kept warm for 1-2 hours. The modified tourmaline is obtained by post-processing.

9. The method for preparing a pet mat that releases negative ions according to claim 7, characterized in that: In step B1, the ratio of titanium tetrachloride, deionized water and tourmaline is 2-3g:80mL:10-12g; in step B2, the ratio of loaded tourmaline, deionized water, anhydrous ethanol and mercaptopropyltrimethoxysilane is 6-8g:20-24mL:10-12mL:1-2g.

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